Innovative Technologies for Printing, Packaging and Digital Media (Lecture Notes in Electrical Engineering, 1144) 9819999545, 9789819999545

Citation preview

Lecture Notes in Electrical Engineering 1144

Huihui Song · Min Xu · Li Yang · Linghao Zhang · Shu Yan   Editors

Innovative Technologies for Printing, Packaging and Digital Media

Lecture Notes in Electrical Engineering

1144

Series Editors Leopoldo Angrisani, Department of Electrical and Information Technologies Engineering, University of Napoli Federico II, Napoli, Italy Marco Arteaga, Departament de Control y Robótica, Universidad Nacional Autónoma de México, Coyoacán, Mexico Samarjit Chakraborty, Fakultät für Elektrotechnik und Informationstechnik, TU München, München, Germany Jiming Chen, Zhejiang University, Hangzhou, Zhejiang, China Shanben Chen, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai, China Tan Kay Chen, Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore Rüdiger Dillmann, University of Karlsruhe (TH) IAIM, Karlsruhe, Baden-Württemberg, Germany Haibin Duan, Beijing University of Aeronautics and Astronautics, Beijing, China Gianluigi Ferrari, Dipartimento di Ingegneria dell’Informazione, Sede Scientifica Università degli Studi di Parma, Parma, Italy Manuel Ferre, Centre for Automation and Robotics CAR (UPM-CSIC), Universidad Politécnica de Madrid, Madrid, Spain Faryar Jabbari, Department of Mechanical and Aerospace Engineering, University of California, Irvine, CA, USA Limin Jia, State Key Laboratory of Rail Traffic Control and Safety, Beijing Jiaotong University, Beijing, China Janusz Kacprzyk, Intelligent Systems Laboratory, Systems Research Institute, Polish Academy of Sciences, Warsaw, Poland Alaa Khamis, Department of Mechatronics Engineering, German University in Egypt El Tagamoa El Khames, New Cairo City, Egypt Torsten Kroeger, Intrinsic Innovation, Mountain View, CA, USA Yong Li, College of Electrical and Information Engineering, Hunan University, Changsha, Hunan, China Qilian Liang, Department of Electrical Engineering, University of Texas at Arlington, Arlington, TX, USA Ferran Martín, Departament d’Enginyeria Electrònica, Universitat Autònoma de Barcelona, Bellaterra, Barcelona, Spain Tan Cher Ming, College of Engineering, Nanyang Technological University, Singapore, Singapore Wolfgang Minker, Institute of Information Technology, University of Ulm, Ulm, Germany Pradeep Misra, Department of Electrical Engineering, Wright State University, Dayton, OH, USA Subhas Mukhopadhyay, School of Engineering, Macquarie University, Sydney, NSW, Australia Cun-Zheng Ning, Department of Electrical Engineering, Arizona State University, Tempe, AZ, USA Toyoaki Nishida, Department of Intelligence Science and Technology, Kyoto University, Kyoto, Japan Luca Oneto, Department of Informatics, Bioengineering, Robotics and Systems Engineering, University of Genova, Genova, Genova, Italy Bijaya Ketan Panigrahi, Department of Electrical Engineering, Indian Institute of Technology Delhi, New Delhi, Delhi, India Federica Pascucci, Department di Ingegneria, Università degli Studi Roma Tre, Roma, Italy Yong Qin, State Key Laboratory of Rail Traffic Control and Safety, Beijing Jiaotong University, Beijing, China Gan Woon Seng, School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore, Singapore Joachim Speidel, Institute of Telecommunications, University of Stuttgart, Stuttgart, Germany Germano Veiga, FEUP Campus, INESC Porto, Porto, Portugal Haitao Wu, Academy of Opto-electronics, Chinese Academy of Sciences, Haidian District Beijing, China Walter Zamboni, Department of Computer Engineering, Electrical Engineering and Applied Mathematics, DIEM—Università degli studi di Salerno, Fisciano, Salerno, Italy Junjie James Zhang, Charlotte, NC, USA Kay Chen Tan, Department of Computing, Hong Kong Polytechnic University, Kowloon Tong, Hong Kong

The book series Lecture Notes in Electrical Engineering (LNEE) publishes the latest developments in Electrical Engineering—quickly, informally and in high quality. While original research reported in proceedings and monographs has traditionally formed the core of LNEE, we also encourage authors to submit books devoted to supporting student education and professional training in the various fields and applications areas of electrical engineering. The series cover classical and emerging topics concerning: • • • • • • • • • • • •

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Huihui Song · Min Xu · Li Yang · Linghao Zhang · Shu Yan Editors

Innovative Technologies for Printing, Packaging and Digital Media

Editors Huihui Song Printing Technology Journals Press Beijing, China

Min Xu Printing Technology Journals Press Beijing, China

Li Yang Printing Technology Journals Press Beijing, China

Linghao Zhang Printing Technology Journals Press Beijing, China

Shu Yan Printing Technology Journals Press Beijing, China

ISSN 1876-1100 ISSN 1876-1119 (electronic) Lecture Notes in Electrical Engineering ISBN 978-981-99-9954-5 ISBN 978-981-99-9955-2 (eBook) https://doi.org/10.1007/978-981-99-9955-2 © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 This work is subject to copyright. All rights are solely and exclusively licensed by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors, and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, expressed or implied, with respect to the material contained herein or for any errors or omissions that may have been made. The publisher remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. This Springer imprint is published by the registered company Springer Nature Singapore Pte Ltd. The registered company address is: 152 Beach Road, #21-01/04 Gateway East, Singapore 189721, Singapore Paper in this product is recyclable.

Preface

“2023 14th China Academic Conference on Printing and Packaging & Forum of Collaborative Innovation of Industry-University-Research”, one of the series “China Academic Conference on Printing and Packaging” which is mainly hosted by China Academy of Printing Technology, was held on November 24–26, 2023, in Beijing, China. Under the guiding of the Printing Technology Association of China, the conference was co-hosted by China Academy of Printing Technology, Beijing Institute of Graphic Communication, and Keyin Media Printing Technology Journals Press and was organized by Key Laboratory of Environmental Protection and Intelligence Technology for Printing Industry School of Printing and Packaging Engineering, Beijing Institute of Graphic Communication, Beijing Key Laboratory of New Technology of Packaging and Printing, and Editorial Department of Printing and Digital Media Technology Study. By far, “China Academic Conference on Printing and Packaging (CACPP)” and its series of events have been held for fourteen sessions and have already become the most influential academic exchange activities in printing and packaging fields in China. In recent years, China’s printing industry adheres to the green, digital, intelligent, and integrated development directions. The industrial structure of the printing industry has been continuously optimized, the industrial efficiency has been significantly improved, the transformation from old driver to new driver has been accelerated, the regional layout has been reasonably evolved, and the printing industry has continued to open wider to the outside world. Constantly strengthening the cooperation and linkage of the printing industry at home and abroad and promoting the global printing industry connectivity, the industry development has embarked on a new journey from big to strong. By 2022, the total output value of China’s printing industry reached 1.43 trillion yuan, and the overall scale ranked first in the world. With the development of new material technology, information technology, and other related technologies, printing is also extending to printing manufacturing and media convergence. A lot of new scientific research results were achieved which were fully communicated at the 14th China Academic Conference on Printing and Packaging and Forum of Collaborative Innovation of Industry-University-Research in 2023. For this academic conference, we specially invited Professor Fei Tao of Beihang University, Professor Guangxue Chen of South China University of Technology, Professor Yanlin Song of Chinese Academy of Sciences, and Professor Long Ye of Communication University of China to make keynote speeches on topics of digital twins and digital engineering, research of printing function prolongation, advanced manufacturing technology of nano-green printing, and digital media technology. At the same time, four parallel symposiums on Innovative Printing and Packaging Technology, Intelligent Technology, Digital Media Technology, and Functional Material Technology were held, in which professors, young scholars, and authors of papers from related universities will participate and conduct reports.

vi

Preface

At the same time, in order to promote the industry-university-research collaborative innovation, the conference invited well-known enterprises to share their innovation experience and also organized the relevant scientific researchers to publish their scientific findings that can be industrially applied, which will strongly promote the combination of scientific research and industry. The conference received 168 papers this year, among which about 73 papers were selected to be published on Lecture Notes in Electrical Engineering (LNEE) (ISSN: 1876-1100) by Springer. Here we greatly acknowledge all the co-sponsors that offered great support for the conference, and they are: College of Light Industry Science and Engineering of Tianjin University of Science and Technology, College of Humanities and Digital Media of Hangzhou Dianzi University, Faculty of Printing, Packaging Engineering and Digital Media Technology of Xi’an University of Technology, Research Center of Graphic Communication, Printing and Packaging of Wuhan University, State Key Laboratory of Modern Optical Instrumentation of Zhejiang University, Faculty of Light Industry of Qilu University of Technology, State Key Laboratory of Biobased Material and Green Papermaking of Qilu University of Technology, School of Light Industry and Engineering of South China University of Technology, State Key Laboratory of Pulp and Paper Engineering of South China University of Technology, State Key Laboratory of Luminescent Materials and Devices of South China University of Technology, College of Materials Science and Engineering of Beijing University of Chemical Technology, College of Bioresources Chemical & Materials Engineering of Shaanxi University of Science and Technology, Light Industry College of Harbin University of Commerce, School of Packaging and Material Engineering of Hunan University of Technology, School of Materials Science and Engineering of Zhengzhou University, School of Light Industry and Chemical Engineering of Dalian Polytechnic University, School of Light Industry of Beijing Technology and Business University, College of Food Science of South China Agricultural University, College of Communication and Art Design of University of Shanghai for Science and Technology, School of Mechanical Engineering of Tianjin University of Commerce, College of Light Industry and Food Engineering of Nanjing Forestry University, School of Mechanical Engineering of Jiangnan University, School of Mechanical Engineering of North University of China, School of Material Science and Engineering of Wuhan Institute of Technology, School of Art and Design of Henan University of Engineering, Jingchu University of Technology, School of Mechanical Engineering of Hebei University of Science & Technology, School of Materials Science and Engineering of Suzhou University of Science and Technology, Quzhou University, Tianjin Vocational Institute, School of Communication of Shenzhen Polytechnic University, and Shanghai Publishing and Printing College. We would like to express our gratitude to the 66 experts from the fields of color, image, computer, material, machinery, and information engineering for their strict reviewing and recommending papers for the conference with strict standards. We also thank Springer for offering us an international platform for publishing.

Preface

vii

We look forward to our reunion at 2024 15th China Academic Conference on Printing and Packaging. November 2023

Edited by China Academy of Printing Technology Keyin Media Printing Technology Journals Press

Committees

Supervisors The Printing Technology Association of China

Sponsors China Academy of Printing Technology Beijing Institute of Graphic Communication Keyin Media Printing Technology Journals Press

Organizers Editorial Department of Printing and Digital Media Technology Study School of Printing and Packaging Engineering, Beijing Institute of Graphic Communication Beijing Key Laboratory of New Technology of Packaging and Printing Key Laboratory of Environmental Protection and Intelligence Technology for Printing Industry

Co-sponsors College of Light Industry Science and Engineering, Tianjin University of Science and Technology College of Humanities and Digital Media, Hangzhou Dianzi University Faculty of Printing, Packaging Engineering and Digital Media Technology, Xi’an University of Technology Research Center of Graphic Communication, Printing and Packaging, Wuhan University State Key Laboratory of Modern Optical Instrumentation, Zhejiang University Faculty of Light Industry, Qilu University of Technology, Shandong Academy of Science State Key Laboratory of Biobased Material and Green Papermaking School of Light Industry and Engineering, South China University of Technology State Key Laboratory of Pulp and Paper Engineering, South China University of Technology State Key Laboratory of Luminescent Materials and Devices, South China University of Technology College of Materials Science and Engineering, Beijing University of Chemical Technology College of Bioresources Chemical and Materials Engineering, Shaanxi University of Science and Technology

x

Committees

Light Industry College, Harbin University of Commerce School of Packaging and Material Engineering, Hunan University of Technology School of Materials Science and Engineering, Zhengzhou University School of Light Industry and Chemical Engineering, Dalian Polytechnic University School of Light Industry, Beijing Technology and Business University College of Food Science, South China Agricultural University College of Communication and Art Design, University of Shanghai for Science and Technology School of Mechanical Engineering, Tianjin University of Commerce College of Light Industry and Food Engineering, Nanjing Forestry University School of Mechanical Engineering, Jiangnan University School of Mechanical Engineering, North University of China School of Material Science and Engineering, Wuhan Institute of Technology School of Art and Design, Henan University of Engineering Jingchu University of Technology School of Mechanical Engineering, Hebei University of Science & Technology School of Materials Science and Engineering, Suzhou University of Science and Technology Quzhou University Tianjin Vocational Institute School of Communication, Shenzhen Polytechnic University Shanghai Publishing and Printing College

Conference Executive Committee Chairmen Zhongli Tian Xiaoxia Chang

Pengfei Zhao

President of Beijing Institute of Graphic Communication Vice Chairman of the Printing Technology Association of China, Vice-General Manager of China Culture Industry Development Corporation President of China Academy of Printing Technology

Vice Chairmen Jiemin Liu Yiping Liu

Vice President of Beijing Institute of Graphic Communication President and Manager of Beijing Keyin Media Culture Co., Ltd.

Committees

xi

Honorary Chairmen Desen Qu Tingliang Chu

Wencai Xu Jialing Pu

Former President of Beijing Institute of Graphic Communication Executive Vice Chairman of the Printing Technology Association of China, Former President of China Academy of Printing Technology Former Vice President of Beijing Institute of Graphic Communication Former Vice President of Beijing Institute of Graphic Communication

Secretary-Generals Yuansheng Qi

Min Xu

Dean of School of Printing and Packaging Engineering, Beijing Institute of Graphic Communication Chief Editor of Printing and Digital Media Technology Study

Conference Academic Committee Chairman Deren Li

Academician of Chinese Academy of Sciences, Academician of China Engineering Academy, Academician of International Eurasian Academy of Sciences, Academician of New York Academy of Sciences, Academician of International Academy of Astronautics, Professor of Wuhan University, Director of State Key Laboratory of Information Engineering in Surveying, Mapping and Remote

xii

Committees

Vice Chairmen Kefu Chen

Jinping Qu

Guangnan Ni

Songlin Zhuang

Academician of Chinese Academy of Engineering, Professor of South China University of Technology, Director of Academic Committee of State Key Laboratory of Pulp and Paper Engineering Academician of Chinese Academy of Engineering, Professor of South China University of Technology, Director of National Engineering Research Center of Novel Equipment for Polymer Processing, Director of the Key Laboratory for Polymer Processing Engineering of Ministry of Education Academician of Chinese Academy of Engineering, Researcher of Institute of Computing Technology Chinese Academy of Sciences, Board Chairperson of Chinese Information Processing Society of China Academician of Chinese Academy of Engineering, Director and Professor of School of Optical-Electrical and Computer Engineering of University of Shanghai for Science and Technology, Optical Expert

Commissioners Alexander Tsyganenko Alexander W. Roos Anita Teleman Aran Hansuebsai Bangyong Sun Benjamin Lee Changqing Fang Changqing Ye Congjun Cao

Professor of Media Industry Academy Professor of Stuttgart Media University Doctor, Research Manager of Printing Solutions at the Research Institute Innventia, Sweden Doctor, Associate Professor of Chulalongkorn University Doctor, Professor of Xi’an University of Technology Doctor, Professor, Director of Department of Technology, California State University Doctor, Professor of Xi’an University of Technology Doctor, Professor of Suzhou University of Science and Technology Doctor, Professor of Xi’an University of Technology

Committees

Dongming Lu Eduard Neufeld Fuqiang Chu Gaimei Zhang Guangxue Chen Guodong Liu Guorong Cao Haiqiao Wang Haoxue Liu Heping Hou Honglong Ning Houbin Li Jialing Pu Jimei Wu Jinda Cai Jinzhou Chen Jon Yngve Hardeberg Jose Maria Lagaron

Junfei Tian Kaida Xiao Kamal Chopra Kun Hu

xiii

Doctor, Professor of Zhejiang University Doctor, Managing Director of Fogra Research Institute for Media Technologies Doctor, Professor of Qilu University of Technology, Shandong Academy of Science Doctor, Professor of Beijing Institute of Graphic Communication Doctor, Professor of South China University of Technology Doctor, Professor of Shaanxi University of Science and Technology Doctor, Professor of Beijing Institute of Graphic Communication Doctor, Professor of Beijing University of Chemical Technology Doctor, Professor of Beijing Institute of Graphic Communication Doctor, Associate Professor of Xi’an University of Technology Doctor, Researcher of South China University of Technology Doctor, Professor of Wuhan University Doctor, Professor of Beijing Institute of Graphic Communication Doctor, Professor of Xi’an University of Technology Doctor, Professor of University of Shanghai for Science and Technology Professor of Zhengzhou University Doctor, Professor of Norwegian University of Science and Technology Doctor, Professor, Leader, and Founder of the Group Novel Materials and Nanotechnology for Food Related Applications at the Institute of Agrochemistry and Food Technology of the Spanish Council for Scientific Research Doctor, Professor of South China University of Technology Doctor, University Academic Fellow of University of Leeds Professor, President of All India Federation of Master Printers Doctor, Senior Engineer of Beijing Institute of Graphic Communication

xiv

Committees

Lei Zhu Lijie Wang Linlin Liu Lixin Lu Luciano Piergiovanni

Luhai Li M. Ronnier Luo Maohai Lin Martin Dreher

Martti Toivakka

Mathias Hinkelmann Mengmeng Wang Min Huang Minchen Wei Ngamtip Poovarodom

Patrick Gane

Pengfei Zhao Phil Green Philipp Urban

Pierre Pienaar

Senior Engineer of Beijing Institute of Graphic Communication Professor of Shenzhen Polytechnic University Doctor, Associate Professor of Xi’an University of Technology Doctor, Professor of Jiangnan University Professor of the Department of Food, Environmental and Nutritional Sciences, Faculty of Agricultural and Food Sciences, University of Milan Doctor, Professor of Beijing Institute of Graphic Communication Doctor, Professor of University of Leeds, Director of Color and Image Science Center Doctor, Professor of Qilu University of Technology, Shandong Academy of Science Doctor, Director, and General Manager of DFTA Technology Center, Professor of the Hochschule der Medien (HdM) Doctor, Professor, and Head of the Laboratory of Paper Coating and Converting at Åbo Akademi University Doctor, Professor of Stuttgart Media University Doctor, Associate Professor of Jiangnan University Doctor, Professor of Beijing Institute of Graphic Communication Doctor, Associate Professor of the Hong Kong Polytechnic University Doctor, Associate Professor of Department of Packaging and Materials Technology of Faculty of AgroIndustry, Kasetsart University Doctor, Professor of Printing Technology at the School of Chemical Technology, Aalto University Senior Engineer of China Academy of Printing Technology Professor of Colour Imaging, London College of Communication Head of Emmy Noether Research Group, Institute of Printing Science and Technology, Technische Universität Darmstadt Professor, President of the World Packaging Organization

Committees

Qiang Liu Qiang Wang Roger D. Hersch

Ruien Yu Ruping Liu Shaozhong Cao Shisheng Zhou Songhua He Stephen W. Bigger Takashi Kitamura

Thomas Hoffmann-Walbeck Tianliang Hu Tingliang Chu Wanbin Pan Wei Wu Weibing Gu

Wencai Xu Xianfu Wei Xiaochun Li Xiaohui Wang Xiaoxia Wan Xiulan Xin Xuesong Mei

xv

Doctor, Associate Professor of Wuhan University Doctor, Professor of Hangzhou Dianzi University Doctor, Professor of Computer Science and Head of the Peripheral Systems Laboratory at the Ecole Polytechnique Fédérale de Lausanne (EPFL) Doctor, Associate Professor of North University of China Doctor, Professor of Beijing Institute of Graphic Communication Doctor, Professor of Beijing Institute of Graphic Communication Doctor, Professor of Xi’an University of Technology Doctor, Professor of Shenzhen Polytechnic University Doctor, Professor, Vice President of Faculty of Engineering and Science of Victoria University Doctor, Professor of Graduate School of Advanced Integration Science, Chiba University Professor of the Faculty of Print and Media Technology, Stuttgart University of Media Doctor, Professor of Shandong University Professorial Senior Engineer of China Academy of Printing Technology Doctor, Associate Professor of Hangzhou Dianzi University Doctor, Professor of Wuhan University Doctor, Senior Engineer of Suzhou Institute of NanoTech and Nano-Bionics, Chinese Academy of Science Professor of Beijing Institute of Graphic Communication Doctor, Professor of Beijing Institute of Graphic Communication Doctor, Professor of Henan University of Engineering Doctor, Professor of South China University of Technology Doctor, Professor of Wuhan University Doctor, Professor of Beijing Technology and Business University Doctor, Professor of Xi’an Jiaotong University

xvi

Committees

Xuying Liu Yadong Yin Ruien Yu Yan Wei Yanlin Song Yao Li Yigang Wang Yingquan Zou Yuansheng Qi Yuemin Teng Yufeng Wang Yunfei Zhong Yungcheng Hsieh Yunhai Wang Yunzhi Chen Yuri Andreev Zhanjun Si Zhengjian Zhang Zhengning Tang Zhi Tang Zhicheng Sun Zhihui Sun Zhijian Li Zhijiang Li Zhuang Liu

Doctor, Professor of Zhengzhou University Doctor, Professor of University of California, Riverside Doctor, Associate Professor of North University of China Doctor, Professor of Tsinghua University, Beijing Institute of Graphic Communication Doctor, Professor of Institute of Chemistry, Chinese Academy of Sciences Doctor, Professor of Harbin Institute of Technology Doctor, Professor of Hangzhou Dianzi University Doctor, Professor of Beijing Normal University Doctor, Professor of Beijing Institute of Graphic Communication Professor of Shanghai Publishing and Printing College Doctor, Senior Engineer of Tianjin University of Science and Technology Professor of Hunan University of Technology Doctor, Professor of National Taiwan University of Arts Doctor, Professor of Shandong University Doctor, Professor of Tianjin University of Science and Technology Head of Moscow State University of Printing Arts Professor of Tianjin University of Science and Technology Doctor, Associate Professor of Tianjin University of Science and Technology Doctor, Professor of Jiangnan University Doctor, Researcher of Wangxuan Institute of Computer Technology, Peking University Doctor, Professor of Beijing Institute of Graphic Communication Professor of Harbin University of Commerce Doctor, Professor of Shaanxi University of Science and Technology Doctor, Professor of Wuhan University Doctor, Professor of Harbin University of Commerce

Committees

xvii

Reviewers Bangyong Sun Beiqing Huang Bin Du Changqing Ye Chen Chen Chuanxia Jian Congjun Cao Fazhong Zhang Fuqiang Chu Gaimei Zhang Guangxue Chen Guangyuan Wu Guodong Liu Hanbin Liu Heping Hou Hongwei Xu Jiangping Yuan Jinda Zhu Jing Liang Junfei Tian Junfeng Li

Doctor, Professor of Xi’an University of Technology Associate Professor of Beijing Institute of Graphic Communication Doctor, Teacher of Xi’an University of Technology Doctor, Professor of Suzhou University of Science and Technology Doctor, Associate Professor of Shenzhen Polytechnic University Doctor, Teacher of Guangdong University of Technology Doctor, Professor of Xi’an University of Technology Doctor, Engineer of China Academy of Printing Technology Doctor, Professor of Qilu University of Technology (Shandong Academy of Science) Doctor, Professor of Beijing Institute of Graphic Communication Doctor, Professor of South China University of Technology Doctor, Associate Professor of Qilu University of Technology (Shandong Academy of Science) Doctor, Professor of Shaanxi University of Science & Technology Doctor, Associate Professor of Shaanxi University of Science & Technology Doctor, Associate Professor of Xi’an University of Technology Associate Professor of Xi’an University of Technology Doctor, Teacher of Shaanxi University of Science and Technology Doctor, Associate Professor of Hebei University of Science & Technology Post-doctor, Lecturer of Dalian Polytechnic University Doctor, Professor of South China University of Technology Doctor, Teacher of Henan University of Animal Husbandry and Economy

xviii

Committees

Junjie Xiao Le Yang Lei Zhu Li An Liangzhe Chen Lijiang Huo Linghua Guo Maohai Lin Mengmeng Wang Ming Mu Ming Zhu Na Wei Peng Cao Qiang Liu Qiang Wang Shanhui Liu Shanshan Gao Shaozhong Cao Shi Li Shibao Wen Shuqin Wu Xianfu Wei Xiaozhou Li Xinghai Liu

Doctor, Associate Professor of Beijing Institute of Graphic Communication Doctor, Teacher of Northeastern University at Qinhuangdao Senior Engineer of Beijing Institute of Graphic Communication Doctor, Associate Professor of Beijing Institute of Graphic Communication Doctor, Associate Professor of Jingchu University of Technology Doctor, Professor of Dalian Polytechnic University Doctor, Professor of Shaanxi University of Science & Technology Doctor, Professor of Qilu University of Technology (Shandong Academy of Science) Post-doctor, Associate Professor of Jiangnan University Engineer of China Academy of Printing Technology Doctor, Professor of Henan Institute of Engineering Professor of Tianjin Vocational Institute Professor of Beijing Institute of Graphic Communication Doctor, Associate Professor of Wuhan University Doctor, Professor of Hangzhou Dianzi University Doctor, Associate Professor of Xi’an University of Technology Doctor, Associate Professor of Qingdao University of Science & Technology Professor of Beijing Institute of Graphic Communication Doctor, Associate Professor of Hangzhou Dianzi University Doctor, Associate Professor of Qingdao University of Science & Technology Associate Professor of Beijing Institute of Graphic Communication Post-doctor, Professor of Beijing Institute of Graphic Communication Doctor, Associate Professor of Qilu University of Technology (Shandong Academy of Science) Doctor, Associate Professor of Wuhan University

Committees

Xue Gong Yalin Miu Yan Li Yanan Liu Yaohua Yi Yi Fang Yigang Wang Yong Lv Yuanlin Zheng Yufeng Wang Yulong Lin Yunzhi Chen Zhanjun Si Zhen Huang Zhengjian Zhang Zhicheng Sun Zhijiang Li Zhiqing Xin Zhuofei Xu

xix

Doctor, Associate Professor of Harbin University of Commerce Doctor, Associate Professor of Xi’an University of Technology Professor of Beijing Institute of Graphic Communication Doctor, Engineer of Quanta Eye (Beijing) Technology Co., Ltd. Doctor, Professor of Wuhan University Doctor, Teacher of Beijing Institute of Graphic Communication Doctor, Professor of Hangzhou Dianzi University Doctor, Professor of Yiwu Industrial & Commercial College Doctor, Associate Professor of Xi’an University of Technology Doctor, Senior Engineer of Tianjin University of Science and Technology Doctor, Teacher of Beijing Institute of Graphic Communication Doctor, Professor of Tianjin University of Science and Technology Professor of Tianjin University of Science and Technology Doctor, Professor of Tianjin University of Commerce Doctor, Associate Professor of Tianjin University of Science and Technology Doctor, Professor of Beijing Institute of Graphic Communication Doctor, Professor of Wuhan University Doctor, Associate Professor of Beijing Institute of Graphic Communication Doctor, Teacher of Xi’an University of Technology

Contents

Color Science and Technology An Exclusion-Reference Image Quality Dataset with Color and Spatial Aspects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Nanlin Xu, Ming Ronnier Luo, and Xinchao Qu

3

Evaluation of Bidirectional Reflectance Distribution Function in the Process of Total Appearance Capture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Kaiwei Zhai, Maohai Lin, Yaoshun Yue, and Wenpeng Sang

11

Reconstruction Algorithm from an Interim Connection Space to Spectra Based on BP Neural Network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Qian Cao

18

Optimal Color Samples for Camera Spectral Sensitivity Estimation . . . . . . . . . . . Hui Fan, Ming Ronnier Luo, and Xinchao Qu

24

Color Correction for Tongue Digital Imaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Zimo Yan, Xiao Yang, Xiaofang Wang, and Yanfang Xu

30

Brief Analysis of the Different Tones of Spot Colors in Digital Printing . . . . . . . Wenjun Guan and Buyan Li

36

Evaluation of Color Measurement Geometries for Optically Variable Inks . . . . . Ziwen Wei, Yu Liu, Yuetong Shen, Xuping Gong, Xiu Li, and Min Huang

45

Image Processing Techniques Unsupervised Low-Light Image Enhancement Algorithm Based on Prior Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Cong Liu and Yigang Wang

55

High-Quality Three-Dimensional Reproduction of the Weak Textures on the Surface of Objects Based on Photometric Stereo -Structural Light . . . . . . Yaoshun Yue, Maohai Lin, Kaiwei Zhai, and Wenpeng Sang

62

Research on High Precision Detection Method of Register Error Based on Machine Vision . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Han Zhang, Shanhui Liu, Xianju Wang, Keliang Wei, and Liang Chen

69

xxii

Contents

Research on Digital Reproduction Mode of Stone Rubbings . . . . . . . . . . . . . . . . . Qi Zeng, Jinglin Ma, and Qian Shi

74

Printing Engineering Technology Study of the Effect of Piezoelectric Inkjet Drive Waveform Parameters on Droplet Injection Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Qiumin Wu, Sa Li, Yili Ma, and Chaoyue Lin

81

Numerical Investigation of the Spreading Behavior of Inkjet Droplets on Rough Substrate Surface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Qiumin Wu, Yili Ma, Sa Li, and Xinyu Cui

88

Research on Digital Inkjet Printability Based on Garment Fabrics . . . . . . . . . . . . Sitong Liu, Jinglin Ma, and Yiyu Zhang

95

Research on 3D Reconstruction Method of Damaged Object Based on Neural Network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102 Wenpeng Sang, Maohai Lin, Yaoshun Yue, and Kaiwei Zhai Research Progress of 3D Printing Silicone Rubber Materials . . . . . . . . . . . . . . . . . 107 Yan Li, Kun Hu, Yongxiang Xu, Yanglan Pei, Zongwen Yang, Lu Han, Luhai Li, and Yen Wei Research Progress of Artificial Vertebral Body and Interbody Fusion Cage . . . . . 120 Zongwen Yang, Kun Hu, Peng Li, and Xiangqian Xu Preparation and Performance Test of 3D Printed Titanium Alloy Intervertebral Fusion Cage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128 Zongwen Yang, Kun Hu, Peng Li, and Xiangqian Xu Research Progress of 3D Bioprinting PEEK Scaffold Material for Bone Regeneration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136 Wenyu Xie, Zongwen Yang, Yixin Zhou, Xiangqian Xu, and Kun Hu Research Progress of 3D Printed Microneedle Blood Glucose Sensor . . . . . . . . . 145 Yixin Zhou, Kun Hu, Ya Zhu, and Xiangqian Xu Surface and Interface Modified Cellulose Nanofibers for Direct Writing and Printing Triboelectric Nanogenerator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153 Xiaofei Fu, Xiaofei Wu, and Zhengjian Zhang Development Trends of Paper and Fabric Based Printed Electronics Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162 Fangdong Wang, Luhai Li, Lixin Mo, Meijuan Cao, Yinjie Chen, Zhiqing Xin, Yi Fang, Xiaoyin Meng, and Hongqi Chen

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Research on “Dragon Scales” Binding Art and Design . . . . . . . . . . . . . . . . . . . . . . 172 Tao Zhang, Fei Liu, Jinglin Ma, and Peng Zhao Packaging Engineering Technology Recent Advancements in Smart Light-Emitting Packaging: Mechanisms, Technologies, and Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181 Jiqing Lian and Yang Zhang Development of an Anti-counterfeiting and Traceability System for Goods Based on RFID Tags . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198 Yongzhao Yang, Peng Liu, Zhongrun Lv, Yujuan Yao, and Minying Zhou Intelligent Management System for Logistics and Storage of Chinese Medical Herbs Based on RFID . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205 Peiyuan Zhu, Gaimei Zhang, Hui Liu, Xiaoli Song, Jiandong Lu, Jiazi Shi, Yonggang Yang, Baiqing Sun, and Jingjing Hu Research on Anthocyanin-Based Indicator Labels and the Freshness Preservation Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212 Yiyang Chen, Hui Liu, Dan Yang, Yabo Fu, and Jiazi Shi Experimental Study on Food Delivery Boxes Utilizing Phase Change Materials for Thermal Energy Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 219 Shubao Zhou Design and Application of Moiré Stripe Packaging Under Interactive Mechanism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225 Chenchen Long, Li Zhou, Yan Wang, Junyan Sun, Baoying Lin, and Liangzhe Chen Simulation Study of Foam Starch Based Material Buffer Model Based on Abaqus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235 Qin Lei, Yin Zhu, Xuanhui Ouyang, Hang Qiu, Wu Liu, and Yunfei Zhong Drop-Impact Analysis of Liquid-Containing Beer Bottles by Finite Element Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244 Xiaoli Song, Chunxiu Zhang, Jiacan Xu, Yuqi Yao, and Wenxiu Guo Design of Structural Parameters for Paper-Based Spherical Porous Materials and Its Influence on Static Cushioning Performance . . . . . . . . . . . . . . . . 253 Xiaoli Song, Gaimei Zhang, Jiandong Lu, Jiacan Xu, Yuqi Yao, and Xinyu Zhang

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Study on Innovative Packaging Design and Protection Performance of Fine Strawberries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 259 Xinyu Cui and Lijiang Huo Experimental Study on the Role of Thermoelectric Cooling System in Short-Distance Food Transportation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 264 Chuan Zhang Mechanical Engineering Technology A Combined Decoupling Controller for Register System of Roll-To-Roll Gravure Printing Machines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273 Chaoyue Wang, Shanhui Liu, Jianrong Li, Guoli Ju, and Wenhui Zhao Fatigue Life Prediction of Web Folding Mechanism’s Machete Arm . . . . . . . . . . 279 Yulong Lin, Tianhao Zhang, and Xinong En Analysis of Key Points in Designing the Contour Curve of the Pressing Cam of Offset Press . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 286 Hongwei Xu, Dailu Guo, Wanjiang Shi, Jiachen Zhang, and Yanwei Xie Systematic Design of Efficient Circulating Oven to Ensure Functional Coating Quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293 Hongqi Chen, Fangdong Wang, Luhai Li, and Yushui Chen Intelligent Optimization Technology in Design of Printing and Packaging Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303 Minwang Liu User Experience Focused Design of Online Printing Quotation System . . . . . . . . 309 Guojun Kang, Huaming Wang, Jiong Liang, Yuansheng Qi, and Jia Wang Numerical Simulation of Two-Component VOCs Gas Treatment in a Three-Bed Regenerative Oxidation Furnace . . . . . . . . . . . . . . . . . . . . . . . . . . . 317 Hao Wan, Jinlong Du, Peng Liu, Xuefan Zhang, Mingying Zhou, and Yujuan Yao Mechanical Properties Analysis for Telescopic Arm of a Trolley for Replace Plates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 323 Haiyang Ji, Li’e Ma, Shilin Feng, Donghao Ma, and Huning Sun

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Printing and Packaging Materials Study to Optimize the Process and Properties of Celery- Based Wrapping Paper Based on Response Surface Methodology . . . . . . . . . . . . . . . . . . . . . . . . . . . 331 Xue Gong, Jiang Chang, Danting Li, Yinglei Zhang, and Lida Hou Study on the Adhesion of UV Ink in Tinplate Printing . . . . . . . . . . . . . . . . . . . . . . 342 Zhenxing Wu and Zhen Wei Printed Preparation of Cellulose-Based Hydrogel Sensors for Human Motion Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 352 Haikuo Zhang and Fuqiang Chu Properties of Charge Transfer Complex Based on Triphenylene Molecule . . . . . . 359 Fuzhou Wang, Chunxiu Zhang, Ao Zhang, Xiaoli Song, Yonggang Yang, Yuguang Feng, Yi Fang, Yaohong Liu, and Ruijuan Liao Preparation and Performance Test of Electrophoretic Particles Modified by Nano TiO2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 365 Jingjing Guo, Chunxiu Zhang, Ruijuan Liao, Yi Fang, Yuguang Feng, Xiaoli Song, Ao Zhang, and Yonggang Yang Preparation and Characterization of Liquid Crystal/Carbon Nanotube/Polyaniline Composites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 370 Xu Zhou and Fuqiang Chu Study on Synthesis of a Novel Luminescent Liquid Crystal and Its Luminescent Properties and Liquid Crystal Performance . . . . . . . . . . . . . . . . . . . . 375 Shiyi Qiao, Chunxiu Zhang, Ruijuan Liao, Yuguang Feng, Xiaoli Song, Yonggang Yang, Ao Zhang, Li An, and Yi Fang Synthesis and Mesomorphism of a Novel Asymmetrical Triphenylene Derivatives Dimer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 380 Jinwei Wang, Chunxiu Zhang, Yuguang Feng, Ao Zhang, Xiaoli Song, Yi Fang, Yaohong Liu, and Ruijuan Liao Research on Electroluminescent Structure and Interactive Application . . . . . . . . 385 Yingmei Zhou and Junwei Qiao Synthesis and Properties of Pentyloxy Triphenylene Bridged Tetraphene . . . . . . 391 Maoxin Zhang, Yi Fang, Chunxiu Zhang, Ruijuan Liao, Yuguang Feng, Ao Zhang, Xiaoli Song, and Yinjie Chen Research Progress and Applications of Electrochromic Materials and Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 397 Jinyu Zeng, Yue Mo, Xin Li, and Guangxue Chen

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Preparation and Adsorption Performance of Heavy Metal Ions of a Complex Hydrogel of Oxidized Nanofibrillated Cellulose/Cationic Guar Gum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 408 Ci Song, Yunfei Bao, Yong Lv, and Deng Ye Preparation and Application of Hydrogel Materials for Interfacial Solar Vapor Generation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 413 Xinghua Du, Lu Han, Zhuoya Liu, Ruping Liu, and Lanlan Hou Fabrication of Flexible Devices by Inkjet Printing . . . . . . . . . . . . . . . . . . . . . . . . . . 418 Lu Han, Xinghua Du, Qinghua Duan, Lanlan Hou, and Ruping Liu Research Progress of MXenes Based Gas Sensors . . . . . . . . . . . . . . . . . . . . . . . . . . 424 Chen Liu, Yabo Fu, Kexin Xue, Jiazi Shi, Meichen Lin, Yingjie Jin, Gaimei Zhang, Dongli Li, Ruijuan Liao, Xinlin Zhang, Dongdong Wang, and Hui Liu Rapid Hydroxylation Modification of Lignin Under H3 BO3 /H2 O2 System . . . . . 431 Chao Li, Qiuhong Zhang, Haiqiang Shi, and Caiyin Wang Preparation of Polymerizable Infrared Absorbing Dye and Lithographic Printing Plate Precursor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 436 Li An, Xinlin Zhang, Ruping Liu, and Zhongxiao Li Study on the Curing Factors of Superhydrophobic Epoxy Resin Anti-fouling Coatings Based on Polydimethylsiloxane Molecular Brush . . . . . . . 443 Chenyang Liu, Zhicheng Sun, Ting Wang, Yibin Liu, Zhenzhen Li, Gongming Li, and Zhitong Yang Application of Manganese Based Catalysts for VOCs Degradation: A Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 448 Kexin Xue, Jiaqi Wei, Yabo Fu, Chen Liu, Jiazi Shi, Gaimei Zhang, Dongli Li, Ruijuan Liao, Xinlin Zhang, Dongdong Wang, and Hui Liu Information Engineering and Artificial Intelligent Technology Long-Text Relation Extraction Model Based on Evidence Sentence Selection and Multi-attention Networks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 457 Yizhang Liu, Guorui Chen, Jiahui Jin, and Zhijiang Li Research on Food Dynamic Pricing Algorithm Based on Deep Reinforcement Learning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 468 Hui Huang and Caiyin Wang

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Active Warning Method for Time-Series Data Based on Integrated Network Model with Multi-head Residuals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 475 Xuebin Zuo, Fan Yang, and Wenjie Yang Analysis of the Adaptability of Key Point Detection Methods on 3D Point Cloud . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 480 Mingwei Cheng, Shanshan Wang, Jiong Liang, Xi Wang, Xiang Chen, and Min Huang Research on the Construction of an Intelligent Drug Package Quality Inspection System Based on Polychromatic Sets Theory . . . . . . . . . . . . . . . . . . . . 491 Jiaxi Ouyang, Linlin Liu, Huanhuan Liu, and Ji Lu Research on Face Gender Recognition System Based on PaddleHub . . . . . . . . . . 499 Xuefan Zhang, Peng Liu, Minying Zhou, Yujuan Yao, and Zhongrun Lv Machine Learning Test for Modulation Range of Ammonium Metatungstate Based Liquid Electrochromic Devices . . . . . . . . . . . . . . . . . . . . . . . 505 Haoyang Yan, Muyun Li, Honglong Ning, Chenxiao Guo, Xinglin Li, Zihan Zhang, Bocheng Jiang, Wei Xu, Rihui Yao, and Junbiao Peng Research on the Quality Evaluation of Remote Maintenance Service for Packaging and Printing Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 514 Yuchen Li, Juhong Chen, Yanfeng Li, Darun Xi, Feiqiang Jiao, and Shanhui Liu Simulation of Machine Vision AGV Autonomous Navigation Based on Monocular SLAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 521 Sicheng Zhou, Peng Liu, MinYing Zhou, Xuefan Zhang, YuJuan Yao, and ZhongRun Lv Design of Print Shop Task Management System Based on Queuing Algorithm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 528 ShuChen Shi and YuanSheng Qi Rapid Correction Method of Human Face Posture in Pitch Perspective . . . . . . . . 536 Wenxin Li and Yigang Wang Sentiment Analysis of Public Opinion on Public Health Events Based on Deep Learning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 543 Moquan Sha and Zhijiang Li Author Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 553

Color Science and Technology

An Exclusion-Reference Image Quality Dataset with Color and Spatial Aspects Nanlin Xu1 , Ming Ronnier Luo1(B) , and Xinchao Qu2 1 State Key Laboratory of Modern Optical Instrumentation, Zhejiang University,

Hangzhou, China [email protected] 2 Dajiang Innovation Technology Co., Ltd, Shenzhen, China

Abstract. High image quality is desired for all imaging devices. Large efforts have been made to accumulate data by human observers and to develop models to fit the visual results. However, most of the earlier works applied the images include color and spatial domains but the visual results were only reported as total image quality, which was found insufficient to build a model. With this in mind, the present experiment studied 816 images collected from two parts, 585 images rendered by color and spatial domain functions from two earlier published datasets (CIDIQ and KADID) and 231 images rendered by color domain functions from the authors’ earlier dataset. The present experiment was conducted using the exclusion-reference (ER) method. Thirty participants took part to evaluate 4 terms: total image quality (tIQ), color image quality (cIQ) and spatial image quality (sIQ) by means of a six categorical judgment method, as well as the weight between color impact and spatial impact (sum to 1). The results showed good repeatability performance between present and earlier visual score were 0.90 and 0.82 correlation coefficient values for CIDIQ and KADID respectively. In addition, weighted IQ obtained through linear weighting with cIQ, sIQ and weight had a greatly high correlation coefficient with tIQ of 0.96, which implies the feasibility of separately considering the color and spatial aspects of image quality. Furthermore, a no-reference images quality model was proposed to predict tIQ, whose accuracy of prediction obtained a correlation coefficient value of 0.80 with 80–20 train-test method. Keywords: Exclusion-reference images quality dataset · Image quality evaluation model

1 Introduction With the popularization of photo capture, task of image quality assessment arises much interest around diverse industries. Compared to traditional subjective scoring methods, image quality assessment models (IQM) offer advantages of convenience and high accuracy. Thus, it is essential to build a concise image quality model and corresponding stable image datasets. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 3–10, 2024. https://doi.org/10.1007/978-981-99-9955-2_1

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IQM can be divided into 3 types; namely, full reference (FR) [1], reduced reference (RR) [2, 3] and no-reference (NR) methods [4]. Among these methods, NR methods is the most widely used and urgently needed by the industry on account of the difficulty of obtaining reference image in the practical application scene. Bianco trained a neural network model called DeepBIQ using a migration learning approach [4]. Model was pre-trained on the public dataset Image-Net and then migrated to individual database for parameter tuning, a test image can be evaluated by being put in a network. Moreover, Z.M. Parvez Sazzad proposed a NR IQM of JPEG2000 images to evaluate the artifact based on pixel distortions and edge information [5]. Meanwhile, several image datasets have been developed and applied extensively in image quality modeling, such as the LIVE database of the University of Texas [6], the TID2008 and TID2013 datasets of the Finnish University of Tampere, the CSIQ dataset of the Oklahoma State University [7, 8], the CIDIQ dataset of the Norwegian University of Science and Technology [9] and the KADID dataset [10] of the University of Konstanz in Germany. Recently, a dataset was developed at the Color and Engineering Lab of Zhejiang University consisting of 47 original images and whole 1600 images rendered by over 6 color domain modifications [11]. Nevertheless, most of the image quality datasets mentioned above focus on color and spatial rendering datasets. The results of these dataset are often linked to overall image quality rather than considered with color and spatial aspects. In this paper, an image dataset was established, that considered the subdivision of image quality and obtained weights for color and spatial aspects from each image. In addition, an image quality model was proposed consisting of 8 attributes that extracted essential information to characterize an image.

2 Preparation of Experimental Images The image collection process involved two distinct approaches. Initially, a subset of 9 and 12 original images was extracted from the CIDIQ and KADID datasets, respectively, as referenced in [8, 9]. Images from CIDIQ were rendered by 5 methods including 2 color rendering and 3 spatial rendering. Similarly, images from KADID were rendered by 5 color rendering and 3 spatial rendering. Consequently, heavily distorted images were omitted from the dataset, resulting in the different levels of rendering details being listed in Table 1. A total of 208 and 377 images were sourced from the CIDIQ and KADID datasets, respectively. Table 1 lists details of image preparation including sources, rendering methods, rendering levels and number of images.

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Table 1. Details of image preparation including sources, rendering methods, rendering levels and number of images Datasets

CIDIQ

KADID

NEW

Selected image

9

12

11

Color rendering

SGCK GM (5 levels) Min DE GM (5 levels)

Color saturation (2-3slevels) Brighten (3–4 levels) Darken (3–5 levels) Mean shift (5 levels) Contrast (5 levels)

Vividness (5 levels) Depth (5 levels) Clarity (5 levels) Chroma (5 levels)

Spatial rendering

Gaussian Blur (4 levels) JPEG (4 levels) JPEG2000 (4 levels)

Gaussian blur (4 levels) JPEG2000 (3 levels) JPEG (3 levels) Sharpness (2 levels)

Final images

208

377

Total images

816

231

Additionally, 11 high-quality images were selected and subsequently rendered utilizing 4 color attribute rendering methods, offering 5 levels of intensity for vividness, depth, clarity, and chroma within the CIELAB color space, as specified in Eq. (1–4). This particular approach yielded a total of 231 images.  (1) vividness = L2 + a2 + b2  depth =

(L − 100)2 + a2 + b2

(2)

 clarity =

(L − 50)2 + a2 + b2

(3)

 a2 + b2

(4)

chroma =

where L, a and b are the CIELAB attributes. Finally, 816 images were collected for using in subsequent experiments. Figure 1 shows all original images prepared.

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Fig. 1. Original images used in subsequent experiments

3 Experimental Design The ER experiment comprised 2 sessions. In the 1st session, participants were asked to evaluate total image quality (tIQ), as well as the weights of its color impact and spatial impact (summing to 1). In the 2ed session, participants were asked to evaluate color image quality (cIQ) and spatial image quality (sIQ). A six categorical judgment method was employed for the evaluation of IQs. Participants were required to rate IQ ratings based on the perceived quality of the displayed images using a keyboard whose values ranged from − 3, very poor; − 2, poor; − 1, little poor; 1, little good; 2, good; to 3, excellent. Here, − 3 corresponds to the lowest perceptual IQ (very poor), whereas + 3 corresponds to the highest (excellent) quality. Prior to the experiment, participants adapted to the experimental conditions for 60 s and then provided the evaluation of the image using the experiment software. In the experiment, 10% of all images were randomly picked out as a repeated group for the purpose of observers’ performance evaluation. The whole ER experiment took about 180 min to complete for each observer. 30 normal observers who performed the Ishihara color vision test between 19 and 29 years of age (mean = 22.2, std = 2.3) participated in the ER experiment including 14 males and 16 females. At the end of the ER experiment, a cumulative total of 133,800 evaluations were obtained.

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4 Experimental Data Analysis To estimate the stability of experimental data, Pearson correlation coefficient (R) was chosen as the evaluation criterion, which was widely applied in psychophysical experiments [11]. For a perfect agreement, R should be 1. Intra- and inter-R were calculated to represent the data consistency of observers using raw data as cov(x, y) (5) std(x) · std(y) where x and y are the refence and batch data respectively and n is the number of images. The mean values of intra-R and inter-R are 0.59 and 0.60 in ER experiment. Additionally, as some images used in experiments are from existing datasets (CIDIQ and KADID), Pearson coefficient between present visual score and old data can be calculated to validate the stability of the experiment results. In the ER experiment, R values are 0.90 and 0.82 for CIDIQ and KADID respectively. Given the number of datasets, the weighted average R value was 0.848 for ER, which indicated the strong stability of whole experimental results. R(x, y) =

wIQ = cIQ ∗ ratiocolor + sIQ ∗ ratiospatial

(6)

Images can be divided into three parts in terms of ratio. 1) ratio-color ≥ 0.6: colordominated image; 2) ratio-color ≤ 0.4: spatial-dominated image; 3) 0.4 < ratio-color < 0.6: normal image. Moreover, weighted IQ can be obtained through linear weighting with ratio, cIQ and sIQ as Eq. (6). Table 2. Correlation coefficients between the IQs R

tIQ

cIQ

sIQ

wIQ

tIQ

1.0

0.720

0.703

0.960

cIQ

0.720

1.0

0.092

0.717

sIQ

0.703

0.092

1.0

0.723

wIQ

0.960

0.717

0.723

1.0

Table 2 lists R between tIQ and other 3 IQs and the correlation coefficients between cIQ and sIQ is close to 0 at 0.092, which indicated that it is feasible to consider image quality in terms of color and spatial quality. Moreover, the high correlation between the wIQ calculated by combining the ratio and tIQ further confirms the accuracy of the experimental design.

5 Image Quality Models To improve the prediction accuracy of the model, the proposed IQM consists solely of 8 attributes listed in Eq. (7) which extracts the key information including chroma (C) of CIELAB color space, chroma contrast 5 × 5 (CC5), sharpness contrast 9 × 9 (CS9), chroma ratio (Cr), clarity ratio (Clr), global contrast (GC), local contrast (LC) and sharpness (S) attributes [11].

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Chroma contrast (CC5) was employed to model the contrast changes in the images. The CC5 value was calculated by taking the average of standard deviations of local image regions of sizes 5 × 5, around all pixels of chroma (C) channels. For sharpness (CS9), edge detection was first applied on the lightness (L) channel using the Sobel operator. Then the standard deviations of local image regions were calculated around the detected edge pixels and averaged to obtain a single value for an entire image. The chroma ratio and clarity ratio values were relative attributes based on the display gamut. IQ = f (C, CC5, CS9, Cr, Clr, GC, LC, S) 1  Cl t N Cl g  1 Ct Cr = N Cg

Clr =

(7) (8) (9)

For certain attributes, the computational procedure is to increase this attribute of the target pixel until it reaches the gamut boundary. Then the end point on the gamut could be regarded as a reference point showed in Fig. 2. The ratio of the target pixel and the reference point attribute is considered the relative attribute value. The ratio value of an image for certain attributes was obtained by averaging the ratio values of all pixels as given by Eq. (8–9).

Fig. 2. Calculation procedure of clarity ratio (Clr). The blue curve is the gamut boundary in the hue page of the target pixel.

In addition to the above-mentioned five attributes, three more image attributes were chosen to build the IQ model, including global contrast (GC), local contrast (LC), and sharpness (S) [11]. To evaluate model’s performance, attributes values were used to train a support vector machine (SVM) regression.

6 Results and Discussion To estimate the accuracy of model’s prediction results, R was also chosen as the evaluation index widely applied in IQMs [1–4]. And for a perfect prediction, R value will be 1. Therefor in this session, for each IQ data, all images were divided into a train set

An Exclusion-Reference Image Quality Dataset

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and a test set by an 80:20 ratio with a random order. In order to ensure the stability of evaluation, this process was repeated 1,000 times. The median value of the correlation coefficient was chosen as the key result of this IQM. Table 3 lists these results of method 1. It can be found that total IQM achieved an R value of 0.796 similar to 0.773 value of weighted IQM which indicates that the proposed IQM has a good performance in predicting IQ of daily life in a commonly accepted sense. What’s more, cIQM achieved the highest R value of 0.84 which implies the proposed IQM is capable of representing the color information of images well. Table 3. Evaluation performance of IQMs with 80–20 training test method R

tIQM

cIQM

sIQM

wIQM

Min

0.681

0.737

0.502

0.651

Median

0.796

0.841

0.685

0.773

Max

0.882

0.903

0.825

0.864

7 Conclusions The primary objective of this study was to accumulate a comprehensive dataset that effectively addresses the different aspects of image quality, specifically focusing on color and spatial features. Additionally, a novel image quality model was proposed. The experimental dataset consisted of a total of 816 images, with some selected from existing datasets while the remaining were generated using color domain renderings. In conclusion, the weighted average correlation coefficient (R values) between the current visual data and the older data was calculated to be 0.848. The high R value indicated a strong consistency of obtained data. Moreover, a high correlation coefficient of 0.96 was found between the total image quality (tIQ) and the weighted image quality (wIQ) obtained through linear weighting with a ratio. This result demonstrated the accuracy of the experimental design methodology and presents an alternative approach for predicting image quality. In addition, a proposed total IQM with an 80–20 train-test method achieved a good R value of 0.80. These results suggested that the model could benefit from further improvement to achieve more precise results. Acknowledgement. This research is supported by National Natural Science Foundation of China (61775190) and Dajiang Innovation Technology Co., Ltd.

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2. Rehman, A., Zhou, R.: Reduced-reference image quality assessment by structural similarity estimation. IEEE Trans. Image Process. 21(8), 3378–3389 (2012). https://doi.org/10.1109/ TIP.2012.2197011. Epub 1 May 2012. PMID: 22562759 3. Yeganeh, H., Wang, Z.: Objective assessment of tone mapping algorithms. In: 17th IEEE International Conference on Image Processing (ICIP 2010), pp. 2477–2480 (2010) 4. Bianco, S., Celona, L., Napoletano, P., et al.: On the use of deep learning for blind image quality assessment. SIViP 12, 355–362 (2018) 5. Sazzad, Z.M.P., Kawayoke, Y., Horita, Y.: No reference image quality assessment for JPEG2000 based on spatial features. Sig. Process. Image Commun. 23(4), 257–268 (2008) 6. Sheikh, H.: Live image quality assessment database release 2 (2005). [2022–04–04] 7. Ponomarenko, N., Lukin, V., Zelensky, A., et.al.: TID2008 – a database for evaluation of fullreference visual quality assessment metrics, 14 (2008) 8. Ponomarenko, N., Jin, L., Ieremeiev, O., et al.: Image database TID2013: peculiarities, results and perspectives. Sig. Process. Image Commun. 30, 57–77 (2015) 9. Liu, X., Pedersen, M., Hardeberg, J.Y.: CID:IQ – A new image quality database 17(6), 503– 510 (2010) 10. Lin, H., Hosu, V., Saupe, D.: KADID-10k: a large-scale artificially distorted IQA database. In: 2019 Eleventh International Conference on Quality of Multimedia Experience (QoMEX), pp. 1–3. IEEE, Berlin, Germany (2019). [2021–08–29] 11. Khan, M.U., Luo, M.R., Tian, D.: No-reference image quality metrics for color domain modified images. J. Opt. Soc. Am. A Opt. Image Sci. Vis. 39(6), B65–B77 (2022). https:// doi.org/10.1364/JOSAA.450595. PMID: 36215544

Evaluation of Bidirectional Reflectance Distribution Function in the Process of Total Appearance Capture Kaiwei Zhai, Maohai Lin(B) , Yaoshun Yue, and Wenpeng Sang State Key Laboratory of Biobased Material and Green Papermaking, Faculty of Light Industry, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China [email protected]

Abstract. Bidirectional reflection distribution function (BRDF) is a function that describes the optical properties of the object surface, which reflects the reflection characteristics of the object surface under different angles, light source direction and observation direction. The research of BRDF has important theoretical and practical value in the fields of computer graphics, computer vision, optics, and could be used to describe surface materials in the real world. Currently, much work has been done on measurement methods, measurement equipment and new measurement models, but limited work has been done on evaluating BRDF. We used an advanced material acquisition equipment-Total Appearance Capture (TAC), The two BRDF models used in this device, Ward model and GGX model, were comprehensively evaluated with comparison function, fitting time and data volume to compare the fitting ability of two different BRDF models for different materials. And the amount of data volume of the two models and the speed of fitting time. Keywords: Bidirectional Reflectance Distribution Function · Evaluation techniques · BRDF model · Comparison functions

1 Introduction Building a comprehensive reflection model to describe the interaction between light and materials is a fundamental problem in computer graphics. In order to synthesize a real scene image, the reflectance of each surface in the scene needs to be fully described. Bidirectional reflectance distribution function (BRDF) has been widely used to describe surface reflectance. BRDF is a model used to describe the reflection properties of the surface of an object. Its purpose is to find the intersection point of the incident light and the surface and the light that is reflected at this point. In this process, the BRDF model calculates the direction and intensity of the reflected light based on the direction of the incident and reflected light, as well as surface properties (such as roughness, material, etc.). BRDF is a common method to describe surface reflectance. Various models have been proposed to approximate BRDFs [1].

© The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 11–17, 2024. https://doi.org/10.1007/978-981-99-9955-2_2

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The device used in this paper, called Total Appearance Capture, is a system for digitizing and rendering the appearance of complex materials. Developed jointly by computer and mechanical scientists in the United States, TAC is a seamless ecosystem comprising of sophisticated instrumentation and intuitive application software that facilitates the acquisition of surface details used to generate highly realistic images for various applications such as digital entertainment, game development, virtual reality, industrial design, and more. There are mainly two kinds of BRDF models used by TAC, Ward model [2] and GGX model [3]. This paper compares the ability of BRDF function to restore real materials through comparison function. In addition, fitting efficiency is another important criterion considered by comparison function when analyzing the differences between different BRDF models. Finally, the two models need to be compared by the amount of data.

2 Techniques First, we compared the ability of different BRDF models to restore real materials through a comparison function, which compares the performance of different BRDF models with this reference value by the difference between the reference reflectance value and the approximate reflectance value. The method adopted in this paper was different from the traditional method. Advanced material acquisition device was used to measure real materials with different BRDF models and then the real material was compared with the BRDF model with different comparison functions, such as mean absolute error, root mean square error or peak signal-to-noise ratio. The comparison function was used to analyze the fitting effect of different BRDF models on real materials. This paper rewrote the formula to make it more intuitive, and the original meaning of the formula remains unchanged. 2.1 Mean Absolute Error (MAE) MAE is the sum of the absolute difference between the reference value yR and the approximate value yA , is shown in Eq. 1, and indicates the mean error margin of the approximate value, regardless of the direction of the error. MAE =

N 1  |yR − yA | N

(1)

i=1

yR is the reference value, yA is the approximate value, and N is the number of samples. The lower the MAE value, the closer the BRDF model results are to the real results, where zero is the best value. Note that MAE should not be used when differences in outliers must be emphasized [4]. Willmott et al. [5] conclude that MAE is the most natural and unambiguous measure of the mean margin of error.

Evaluation of Bidirectional Reflectance Distribution Function

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2.2 Mean Square Error (MSE) MSE can evaluate the degree of change in the data. It measures the average square error between the approximate value of the model and the reference value, is shown in Eq. 2. MSE =

N 1  (yR − yA )2 N

(2)

i=1

The smaller the value of MSE, the smaller the difference between the approximate value and the true value of the model, and the better the performance of the model. 2.3 Root Mean Square Error (RMSE) RMSE is the arithmetic square root of the MSE. RMSE is introduced because the dimension of the mean square error is different from the data dimension and cannot directly reflect the degree of dispersion, so the square root is opened on the mean square error to obtain the root mean square error, is shown in Eq. 3.   N 1  (3) RMSE =  (yR − yA )2 N i=1

The lower RMSE value means less difference between the predicted and reference value and better performance of the model. Tongbuasirilai et al. [6] used RMSE to analyze their proposed model. 2.4 Peak Signal-to-Noise Ratio (PSNR) PSNR is designed to assess the quality of the reconstructed image when compared to the original image [4]. The ratio used to represent the maximum possible power of a signal and the power of destructive noise that affects the fidelity of its representation, is shown in Eq. 4.  2 2b − 1 (4) PSNR = 10log10 MSE where b represents the number of bits used by each pixel, also known as the bit depth of the image. In contrast to MSE, a larger PSNR indicates better model performance, and Ozturk et al. [7] used PSNR to compare their proposed model with a reference reflectance model.

3 Experiment The BRDF evaluations in this paper differs from others. We used real materials for our evaluation and compared them with those fitted with different BRDF models. One of the most important is the comparison processing using the PANTORA application of X-rite

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[8]. Different comparison functions were selected to analyze and compare the two kinds of BRDF models, so as to analyze the reproduction effect of different BRDF models on different materials. In addition, it was necessary to record the measurement time and compare the amount of data, and comprehensively compare the fitting results of the two functions through three ways. The database was constructed by ourselves, and the materials used were easy to obtain. However, due to the large amount of data and long collection time, the number of materials was small. However, we still chose more representative materials for measurement as far as possible. For example, isotropic materials also had anisotropic materials, high-gloss materials, and low-gloss materials, and in the future, we continued to expand our material library (Fig. 1).

Fig. 1. Material database based on TAC

In this paper, twelve different materials were measured, all of which were based on our own measurement database. Each material was measured using two different models and analyzed with different comparison functions. Previous works generally used the MERL BRDF database, which was measured by Matusik et al. at Mitsubishi Electronics Research Laboratory (MERL) [9]. For the convenience of subsequent analysis, we used numbers to represent the twelve materials, details are shown in Table 1. 3.1 Evaluation In this paper, TAC was used to analyze and test the fitting effect of the two BRDF models on different materials. 12 kinds of materials were taken as examples to analyze two BRDF models. Figure 2 showed how well the two comparison functions fitted. If only the comparison function was used to evaluate the two models, then it could be found that only four materials with a better fitting effect of the Ward model were better than the GGX model. The four materials with a better fitting effect of the Ward model were material 1 green leather and material 2 black leather, material 5 Gy carpet, and material 10 textured fabric. These materials were highly roughness materials, because the Ward model used a double-beveled plane to simulate the reflection of multiple layers of light, so it could capture the complexity of the surface microstructure of the object [2]. For the other eight materials, the fitting effect of the GGX model was better than that of the Ward model, there were not only metal materials such as high-gloss materials but also wood materials and paper materials with lower roughness. The characteristics of the GGX model were

Evaluation of Bidirectional Reflectance Distribution Function

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Table 1. Number of the twelve materials Material number

Material name

1

Green leather

2

Black leather

3

Black sheet metal

4

Colorless sheet metal

5

Grey carpet

6

Cotton sheet

7

Corrugated paper

8

Wood

9

Leather grain paper

10

Textured fabric

11

Woven paper

12

Plastic

that the surface reflection highlight had a smoother edge, and the higher roughness value had a more obvious impact on the reflected highlight area [3]. For material 3, the GGX model performs better than the Ward model in terms of fitting effect and fitting time. For material 4, although the Ward model has a slightly faster fitting speed than GGX, the GGX model still outperforms Ward due to its better fitting effect. For material 12, two comparison functions showed that GGX was better than Ward, and the results of the two comparison functions were opposite. Therefore, for material 12 plastic sheet, we need to compare the fitting time again. Through comparison, we found that GGX is faster than Ward, so we finally concluded that GGX is better than Ward for materials with high light. From Fig. 2, we could find that the Ward model had a higher fitting effect than the GGX model only for materials with high roughness, but for other materials, especially high-light materials, the Ward model fitting effect was relatively poor. However, we should not only consider the fitting effect, the measurement time and data volume were also important factors. Figure 3b showed the comparison of the data volume of 12 materials. Through comparison, we found that the data volume of 12 materials using TAC was very close, for the four kinds of high roughness materials, the data volume of Ward model and GGX model was almost the same. However, Fig. 3a showed that the fitting time of the Ward model was much faster than that of the GGX model. Therefore, for some high roughness materials, Ward model was a better choice. Figure 3a showed that for other materials, except material 3 black sheet metal and material 12 plastic, which were two materials with high gloss, the fitting time of other materials in the Ward model was much faster than that of the GGX model. However, due to the poor fitting effect of the Ward model on high-light materials, GGX model was still better than Ward model for high-light materials.

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a.MAE

c.RMSE

b,MSE

d.PSNR

Fig. 2. Four comparison functions are used to compare the two BRDF models

a.fitting time

b.data volume

Fig. 3. Fitting time and data volume of the two models

4 Conclusions In this paper, two BRDF models were comprehensively compared by comparison functions, fitting time and data volume in the process of total appearance capture. By comparison, the fitting effect of the two models on different materials was analyzed. And the advantages and disadvantages of the two models were analyzed. Through comparison, we found that under the condition of almost the same amount of data, the fitting effect of the GGX model for most materials (except high roughness materials) was better than

Evaluation of Bidirectional Reflectance Distribution Function

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that of the Ward model, and the fitting time of the Ward model for most materials (except a few high gloss materials) was faster than that of the GGX model. In the future work, we will continue to measure different materials to improve our database, and we can build our own material acquisition system according to the existing data.

References 1. Haindl, M., Filip, J.: Accurate material appearance measurement, representation and modeling. Adv. Comput. Vis. Pattern Recogn. (2013). https://doi.org/10.1007/978-1-4471-4902-6 2. Ward, G.J.: Measuring and modeling anisotropic reflection. In: Proceedings of the 19th Annual Conference on Computer Graphics and Interactive Techniques (1992) 3. Walter, B., Marschner, S.R., Li, H., Torrance, K.E.: Microfacet models for refraction through rough surfaces. In: Proceedings of the 18th Eurographics Conference on Rendering Techniques (2007) 4. da Silva Nunes, M., Melo Nascimento, F., Florêncio Miranda Jr., G., Trinchão Andrade, B.: Techniques for BRDF evaluation. Vis. Comput. 573–589 (2022) 5. Willmott, C.J., Matsuura, K.: Advantages of the mean absolute error (MAE) over the root mean square error (RMSE) in assessing average model performance. Climate Res. 79–82 (2005) 6. Tongbuasirilai, T., Unger, J., Kronander, J., Kurt, M., Compact and intuitive data-driven BRDF models. Vis. Comput. 855–872 (2020) 7. Ozturk, A., Kurt, M., Bilgili, A., Gungor, C.: Linear approximation of bidirectional reflectance distribution functions. Comput. Graph. 149–158 (2008) 8. Mueller, G., Lamy, F.: Proposal for an Appearance Exchange Format, Material Appearance Modeling (2015) 9. Matusik, W.: A data-driven reflectance model. Massachusetts Institute of Technology (2003)

Reconstruction Algorithm from an Interim Connection Space to Spectra Based on BP Neural Network Qian Cao(B) Department of Printing and Packaging Engineering, Shanghai Publishing and Printing College, Shanghai, China [email protected]

Abstract. An interim connection space (ICS) composed of two sets of tristimulus values under two different illuminants (D50 , D65 ) is proposed and a reconstruction algorithm based on BP neural network to convert the ICS into spectra. In order to test and compare the performance of the proposed ICS with the other four ICS, the NCS spectral dataset is used as training samples, and NCS and Munsell spectral datasets are used as testing samples. The root mean square error (RMSE) between the original and reconstructed spectra is used to evaluate the spectral accuracy. The average values of mean color difference between the original and reconstructed spectra under various lighting conditions is used to evaluate the colorimetric accuracy. The experimental results show that the proposed ICS has the best performance in spectral accuracy and colorimetric accuracy compared to the other ICS, and has obvious advantages compared to the other four ICS. Keywords: Spectral color reproduction · Interim connecting space · BP neural network · Spectral reconstruction

1 Introduction In recent years, in order to avoid and eliminate the problem of “metamerism” in traditional color reproduction, the theory and technology of spectral color reproduction has become a hot topic in color science [1–3]. However, the spectral data used is usually more than ten times the traditional color reproduction system. These huge spectral data cause a huge burden in storage, processing and transmission. In the spectral color reproduction, it is necessary to define an interim connection space (abbreviated as ICS) as a bridge for the conversion between spectra and device driver values [4–7]. This transform from spectra to device driver values is divided into two steps: transformation from spectra to an ICS and then transformation from an ICS to device driver values. In 2006, Derhak and Rose [4] constructed an interim connection space named LABPQR. The first three dimensions of LABPQR are LAB values under D50 lighting conditions, while the last three dimensions are obtained by principal component analysis. In 2008, Nakaya [6] constructed the interim connecting space named LABRGB. The first 3 dimensions of LABRGB are also composed of LAB values under the specified illuminant, and the last © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 18–23, 2024. https://doi.org/10.1007/978-981-99-9955-2_3

Reconstruction Algorithm from an Interim Connection Space

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3 dimensions are composed of RGB values. In 2004 Fairman et al. [5] proposed that an interim connection space is composed of three stimulus values under two illuminants (labeled as XYZXYZ-Fairman for comparison), and proposed mutual conversion algorithms between spectra and XYZXYZ-Fairman. The dimensions of XYZXYZ-Fairman all have colorimetric significance and can be well compatible with traditional color management system. In 2012 Zhang et al. [7] proposed XYZLMS. The first three dimensions of XYZLMS are XYZ values, which has chromaticity significance, while the last three dimensions are positive, which has a certain physical significance. When two sets of chromaticity values form an ICS, the reconstruction algorithm from the ICS to the high-dimensional spectra is the focus of research, and different reconstruction algorithms will lead to different colorimetric and spectral reconstruction accuracy. In this paper Back Propagation (BP) neural network is used to convert an ICS to spectra.

2 Method This paper proposes two sets of tristimulus values under different lighting sources to form an interim connection space. The following derivation of the mutual conversion between the interim connection space and high-dimensional spectra proposed. 2.1 Conversion of High-Dimensional Spectra to the Proposed Interim Connection Space (High-Dimensional Spectra Compression) According to the formula for calculating tristimulus values, X 1 , Y 1 , and Z 1 are tristimulus values of spectral dataset R under illuminant I1 (λ) and X 2 , Y 2 and Z 2 are tristimulus values of spectral dataset R under illuminant I2 (λ). I1 (λ) and I2 (λ) refer to the spectral power distribution of light source 1 and light source 2, respectively. ⎡ ⎤ ⎡ ⎤ k1 x(λ)diag(I1 (λ))λ X1 ⎢ Y ⎥ ⎢ k y(λ)diag(I (λ))λ ⎥ 1 ⎢ 1⎥ ⎢ 1 ⎥ ⎢ ⎥ ⎢ ⎥ ⎢ Z1 ⎥ ⎢ k1 z(λ)diag(I1 (λ))λ ⎥ (1) ⎢ ⎥=⎢ ⎥·R ⎢ X 2 ⎥ ⎢ k2 x(λ)diag(I2 (λ))λ ⎥ ⎢ ⎥ ⎢ ⎥ ⎣ Y2 ⎦ ⎣ k2 y(λ)diag(I2 (λ))λ ⎦ Z2 k2 z(λ)diag(I2 (λ))λ where, k1 = 100/(y(λ)I1T (λ)λ)

(2)

k2 = 100/(y(λ)I2T (λ)λ)

(3)

and

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Fig. 1. Schematic diagram of BP neural network

2.2 Conversion from the Proposed ICS to High-Dimensional Spectra (Reconstruction of High-Dimensional Spectra) By using the proposed XYZXYZ as the input variable of the BP neural network and spectra as the output variable of the BP neural network, a conversion model from an ICS to spectra is established, as shown in Fig. 1.

3 Experiment and Process 3.1 Experimental Data In this paper, two spectral datasets of NCS and Munsell [8] are used as experimental data, which are composed of 1,950 and 1,600 colors of spectral data respectively. 3.2 Experimental Process Determine the parameters of the conversion model from the proposed XYXXYZ to spectra. After a large number of experiments and tests, in the reconstruction process from the proposed XYZXYZ to the high-dimensional spectra, the optimal BP neural network is used as follows: 3-layer neural network, the hidden layer and output layer respectively select logsig and purelin as the activation function, the network training algorithm is trainlm, and the number of hidden layers is 20. When NCS spectra are used as training samples, the spectral datasets of NCS and Munsell are used respectively as test samples to test and evaluate the performance of the proposed ICS and the other four ICS. 3.3 Evaluation Indicators There is an error between the original and reconstructed spectra, which is mainly evaluated by the colorimetric and spectral accuracy. The spectral accuracy is evaluated through root mean squared error (RMSE). Small root mean square error represents high spectral

Reconstruction Algorithm from an Interim Connection Space

21

accuracy. The CIE 1976 color difference is used to evaluate the colorimetric accuracy, and small color difference means high colorimetric accuracy. The CIE illuminants A, D50, D55, D65, D75, F2, F7 and F11 are chosen to be representative of various light sources for estimating color differences.

4 Results and Discussion The colorimetric and spectral accuracy of the proposed XYZXYZ and the other four ICS are compared. 4.1 Comparison of Colorimetric Accuracy Between the Proposed XYZXYZ and the Other ICS Table 1 lists the mean color difference under the condition of lighting sources when NCS is used as training samples and NCS as test samples. And the average value of the mean color difference under various lighting conditions. As shown in Table 1, the performance of the ICS is sorted as follows according to the average value of the original and reconstructed spectra of the test samples under different lighting conditions: the proposed XYZXYZ, XYZXYZ-Fairman, LABPQR, XYZLMS, LABRGB. Table 1. Colorimetric Accuracy of NCS Reconstructed by Using NCS as training sample LABPQR

XYZXYZ-Fairman

XYZLMS

LABRGB

Proposed XYZXYZ

A

0.0839

0.0240

0.3456

0.6022

0.1002

D50

0.0019

0.0326

0.0908

0.1724

0.0856

D55

0.0213

0.0256

0.0526

0.1059

0.0846

D65

0.0525

0.0149

0.0143

0.0289

0.0834

D75

0.0744

0.0131

0.0451

0.0809

0.0825

F2

0.5336

0.4294

0.6495

1.2065

0.1705

F7

0.2694

0.2302

0.2405

0.4586

0.1150

F11

1.0037

1.0675

1.0434

1.6771

0.5456

Average

0.2551

0.2297

0.3102

0.5416

0.1584

When NCS is the training sample and Munsell is the test sample, the statistical results of colorimetric accuracy are shown in Table 2. As shown in Table 2, when the test sample is Munsell, the performance ranking of the five kinds of ICS in colorimetric accuracy is the proposed XYZXYZ, XYZXYZ-Fairman, LABPQR, XYZLMS, LABRGB. Therefore, the proposed XYZXYZ is the best colorimetric performance of the ICS.

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Table 2. Colorimetric Accuracy of Munsell Reconstructed by Using NCS as training sample LABPQR

XYZXYZ-Fairman

XYZLMS

LABRGB

Proposed XYZXYZ

A

0.1096

0.0294

0.4450

0.6609

0.1228

D50

0.0000

0.0410

0.1192

0.1835

0.1072

D55

0.0226

0.0325

0.0708

0.1120

0.1062

D65

0.0593

0.0196

0.0171

0.0322

0.1051

D75

0.0857

0.0160

0.0578

0.0901

0.1044

F2

0.6065

0.4827

0.7429

1.2987

0.2463

F7

0.3415

0.2773

0.2767

0.4614

0.1790

F11

1.6398

1.5778

1.4490

1.8417

0.9910

Average

0.3581

0.3095

0.3973

0.5851

0.2452

4.2 Comparison of Spectral Accuracy Between the Proposed XYZXYZ and the Other Four Kinds of ICS Table 3 statistics the mean value of root mean square error of the original and reconstructed spectra when NCS spectra are used as the training samples and the test samples are NCS and Munsell spectra respectively. As can be seen from Table 3, when the test samples are NCS spectra, the performance ranking of spectral accuracy is as follows: proposed XYZXYZ, LABPQR, XYZLMS, LABRGB, XYZXYZ-Fairman. When the test samples are Munsell spectra, the performance ranking of spectral accuracy is as follows: proposed XYZXYZ, LABPQR, XYZLMS, LABRGB, XYZXYZ-Fairman. In conclusion, the proposed XYZXYZ has the best spectral accuracy and XYZXYZ-Fairman has the worst spectral accuracy. The other three ICS are arranged in the middle position and changed with different test samples. Table 3. Comparison of spectral accuracy (RMSE) between the proposed XYZXYZ and the other four methods LABPQR

XYZXYZ-Fairman

XYZLMS

LABRGB

Proposed XYZXYZ

NCS

0.0091

0.0168

0.0110

0.0153

0.0069

Munsell

0.0115

0.0196

0.0123

0.0160

0.0112

5 Conclusion An ICS composed of two sets of tristimulus values is proposed, and a reconstruction algorithm based on BP neural network to convert the ICS into spectra. The experimental results show that the proposed XYZXYZ has the best performance in spectral

Reconstruction Algorithm from an Interim Connection Space

23

accuracy and colorimetric accuracy compared to the other ICS, and has obvious advantages compared to the other four ICS. The proposed ICS can be used as a bridge between high-dimensional spectra and device driver values in spectral color reproduction system. Acknowledgments. This study is funded by Key Lab of Intelligent and Green Flexographic Printing (KLIGFP-03).

References 1. Wang, L., Wan, X., Xiao, G., et al.: Sequential adaptive estimation for spectral reflectance based on camera responses. Opt. Express 28(18), 25830–25842 (2020) 2. Safdar, M., Emmel, P.: Perceptually uniform cross-gamut mapping between surface colors. JOSA A 38(1), 140–147 (2021) 3. Liu, Q., Huang, Z., Pointer, M.R., et al.: Optimizing the spectral characterisation of a CMYK printer with embedded CMY printer modeling. Appl. Sci. 9(24), 5308 (2019) 4. Derhak, M., Rosen, M.: Spectral colorimetry using LabPQR: an interim connection space. J. Imaging Sci. Technol. 50(1), 53–63 (2006) 5. Fairman, H.S., Brill, M.H.: The principal components of reflectances. Color. Res. Appl. 29(2), 104–110 (2004) 6. Nakaya, F., Ohta, N.: Spectral encoding/decoding using LabRGB. J. Imaging Sci. Technol. 52(4), 40902-1–40902-8 (2008) 7. Zhang, X., Wang, Q., Wang, Y., et al.: XYZLMS interim connection space for spectral image compression and reproduction. Opt. Lett. 37(24), 5097–5099 (2012) 8. University of Eastern Finland, Computational Spectral Imaging, Spectral Database. https:// sites.uef.fi/spectral/databases-software/spectral-database. Accessed 09 May 2023

Optimal Color Samples for Camera Spectral Sensitivity Estimation Hui Fan1 , Ming Ronnier Luo1(B) , and Xinchao Qu2 1 State Key Laboratory of Modern Optical Instrumentation, Zhejiang University,

Zhejiang, China [email protected] 2 Dajiang Innovations Technology Co., Ltd, Shenzhen, Guangdong, China

Abstract. This study investigated the optimal color samples for camera spectral sensitivity estimation. Principal component analysis (PCA) was performed on a public camera spectral sensitivity database. The eigenvectors were extracted and served as the basis functions, and the coefficients were calculated by a classical least square method. The color samples for spectral sensitivity estimation included a multichannel LED device and a reflective color chart. Three sample selection methods were implemented, which were based on minimizing the condition number, maximizing the minimum distance in the chromaticity plane, and using a simulated imaging system, respectively. It was found all the three methods were able to find the optimal color samples. The spectral sensitivity estimation error decreased and then became stable with the increase of the number of color samples. Keywords: Camera · Spectral sensitivity · Optimal color samples

1 Introduction Spectral sensitivity represents the responses of a camera to the lights at different wavelength. This information can be applied in the fields including multispectral imaging, color constancy, filter design, etc. The direct calibration method is to use a monochromator [1]. However, this method requires multiple shots and costly device. Prior studies have been carried out to estimate camera spectral sensitivities by capturing a series of color samples with known spectra information [2–9]. Various algorithms and different color samples have been applied. The algorithms included truncated singular value decomposition [2], basis functions [3], principal component analysis (PCA) [4, 5, 7, 9], regularization [8], etc. In general, the number of color samples affected the camera capture times, and thus determined the measurement efficiency. Therefore, it was necessary to select a few optimal color samples from the total set. Hardeberg et al. [10] presented an algorithm based on the minimization of condition number of reflectance matrix, for the choice of optimal samples with a reduced number in camera spectral sensitivity estimation. While some algorithms were proposed for the selection of representative training samples in spectral reflectance reconstruction [11–13]. However, it © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 24–29, 2024. https://doi.org/10.1007/978-981-99-9955-2_4

Optimal Color Samples for Camera Spectral Sensitivity Estimation

25

was not clear whether these algorithms could be applied to the field of sample selection in spectral sensitivity estimation. Moreover, it should be noted most of the previous studies on spectral sensitivity estimation used reflective surface color samples. Only a few studies focused on the multichannel LED, but seldom investigated its sample selection problem, or compared different sample selection methods. In this study, the spectral sensitivities were estimated using a PCA method together with a public spectral sensitivity database. Two types of color samples were utilized, including a multichannel LED device and a reflective color chart. Three sample selection methods were implemented to select different numbers of optimal color samples. The spectral sensitivity estimation accuracy was evaluated by both spectral and colorimetric metrics. It was found the accuracy firstly increased and then became nearly stable with the increase of the number of color samples.

2 Method The camera spectral sensitivity estimation was usually carried out using the linear camera responses. The camera responses (X ) were the integration of the product of the spectral sensitivities of the camera (S) and the spectral radiance of the objects (L) over wavelength. For surface color, the spectral radiance was the product of the spectral reflectance of object and the SPD (spectral power distribution) of light. After sampling the wavelength (400nm to 700nm with a 10nm interval in this study), it can be formulated by Eq. (1). X = LS

(1)

In general, spectral sensitivity estimation required the known spectral signals L and the corresponding camera responses X . A previous study [7] collected a spectral sensitivity database by combining four public databases [3–5, 14], including 111 cameras in total. After performing PCA on the spectral sensitivities in the database, the eigenvectors can be considered as basis functions to represent the spectral sensitivities as Eq. (2), where B is the eigenvector matrix and a is the coefficients. S = Ba

(2)

Substituting Eq. (2) into Eq. (1), the least square solution of S can be calculated by Eq. (3). The superscripts T and −1 denote the matrix transpose and inverse. mina ||LBa − X ||2 S = B[(LB)T (LB)]

−1

(LB)T X

(3)

Different sample selection methods have been proposed. This study implemented and compared three methods, i.e., minimized condition number (minCondNum) [10], MAXMINC [11], and simulated system (simuSys) [13]. The minCondNum method [10] selected the first sample with the maximum rootmean-square value of spectral reflectance (for surface colors) or spectral radiance (for

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self-luminance colors). The following samples were selected in turn with the aim of minimizing the condition number (the ratio of the largest to the smallest singular value) of the spectral reflectance or spectral radiance matrix. A set of most significant color samples would be selected following this method. MAXMINC method [11] selected the first color sample using the same way as the above method. The following samples were selected in turn in order to maximize the minimum distance with the other selected samples in the chromaticity plane. This method confirmed the selected color samples to uniformly span the whole chromaticity plane. The simuSys method [13] was based on a representative simulation system following Eq. (1). In this study, the spectral sensitivities of the simulated imaging system were randomly selected from the camera database [7]. The optimal color samples were selected to minimize a defined objective function in simulation experiments. In this study, it was the error of spectral sensitivity estimation, i.e., the linear combination of spectral error (SE) [15] and colorimetric error CIEDE2000 (E ∗00 ) [16] as Eq. (4). In this study, it was decided to set a = 1 and b = 0.1. The selected color samples by the simulated system were tested in practical experiments. obj = a ∗ SE + b ∗ E ∗00

(4)

3 Experiment The test camera was a professional DSLR camera Canon 650D. The ground-truth spectral sensitivities were calibrated by a Labsphere QES1000 monochromator. The LED device was a Thouslite 18-channel LED system, and the reflective color sample was an Xrite Macbeth ColorChecker chart (MCCC). The camera was used to capture the images of the multiple LED channel at the light-emitting plane in a dark room, and to capture the color chart under simulated D50, D65, and A illuminants. For the color chart, the spectral sensitivity estimation was carried out under D65, while the estimation accuracy was tested under D50 and A. Figure 1 shows the experimental condition. It was exactly the same as our previous study[7].

a.LED samples b.reflective color chart. Fig.1. Experimental conditions a) LED samples b) reflective color chart.

Optimal Color Samples for Camera Spectral Sensitivity Estimation

27

The three sample selection methods were applied to the two types of samples, respectively. The spectral sensitivity estimation was conducted using different numbers of color samples. The estimated accuracy was evaluated by four different metrics, spectral error (SE), color difference E ∗00 , RGB error, and Vora value [7]. Among them, SE and Vora value were spectral metrics indicating the similarity with the ground truth spectral sensitivities measured by the monochromator, and E ∗00 and RGB error were colorimetric metrics tested by MCCC under D50 and A. The RGB error was calculated between the measured camera responses and those predicted by the estimated spectral sensitivities.

4 Results and Discussion Figure 2 plots the spectral sensitivity estimation error with different numbers of color samples in terms of the four metrics. It can be seen that with the increase of the number of color samples, the estimated error decreased and then became nearly stable. Due to the presence of camera noise, the results had some small oscillations. The colorimetric metrics had higher speed of convergence compared to the spectral metrics. (a)SE

0.14

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0.035

minCondNum(LED) MAXMINC(LED) simuSys(LED) minCondNum(MCCC) MAXMINC(MCCC) simuSys(MCCC)

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Fig.2. Spectral sensitivity estimation accuracy with different number of color samples. The solid and dashed lines were the results of the LED and MCCC samples, respectively. The error metrics ∗ , and (d) Vora value. were (a) SE, (b) RGB error, (c) E00

Comparing the two types of color sample, the LED samples achieved higher estimated accuracy in terms of SE and Vora value. The MCCC samples had higher accuracy ∗ in most cases. While the relationship of RGB error depended on the in terms of E00 number of samples. When using MCCC as color samples, the minimized objective of the least square solution was the error of camera responses to the color chart under D65, which could contribute to higher accuracy tested by the same color chart under D50 and

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A. Nevertheless, considering the lower colorimetric error but higher spectral error, when using the MCCC samples, the estimated results might be the metamers of the ground truth spectral sensitivities. And it can be observed that the MCCC samples required more numbers of samples (more than 10) than LED samples (about 6) to achieve relatively stable SE values. Considering the overall tendency of estimated error, it was decided to present the systems with six optimal color samples. Figure 3 plots the spectra and chromaticity of the optimal LED and MCCC color samples selected from different methods. Spectral radiance and spectral reflectance were plotted for the two types of samples, respectively. The chromaticity was both plotted in the CIE 1976 u’v’ plane. It can be seen that the samples selected by MAXMINC method were more uniformly distributed in the chromaticity plane. The chromaticity of the LED samples was much more saturated and was close to the spectral locus due to the narrowband feature, so that it was not surprising to result in higher spectral accuracy and serve as more suitable color samples for spectral sensitivity estimation. LED minCondNum

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Fig.3. Spectral radiance/reflectance and chromaticity in u’v’ plane of the six optimal LED and MCCC color samples selected by the three sample selection methods.

5 Conclusion In this study, three sample selection methods were implemented for camera spectral sensitivity estimation. The three methods were based on minimizing the condition number, maximizing the minimum distance in the chromaticity plane, and using a simulated imaging system, respectively. Different numbers of optimal color samples were selected. Two types of color samples were used, including a multichannel LED device and a reflective color chart MCCC. It was found with the increase of the number of color samples, the spectral sensitivity estimation error decreased and then became basically stable. Using LED samples resulted in higher spectral accuracy, while MCCC samples led to slightly higher colorimetric accuracy. All the three sample selection methods succeeded to find the optimal color samples. Finally, the systems with six optimal color samples were obtained.

Optimal Color Samples for Camera Spectral Sensitivity Estimation

29

Acknowledgement. This research is supported by National Natural Science Foundation of China (61775190), and Dajiang Innovations Technology Co., Ltd.

References 1. Darrodi, M.M., Finlayson, G., Goodman, T., Mackiewicz, M.: Reference data set for camera spectral sensitivity estimation. J. Optical Soc. Am. a-Optics Image Sci. Vis. 32(3), 381–391 (2015) 2. DiCarlo, J.M., Montgomery, G.E., Trovinger, S.W.: Emissive chart for imager calibration. Color Imaging Conf. 12(1), 295–301 (2004). https://doi.org/10.2352/CIC.2004.12.1.art00052 3. Zhao, H., Rei, K., Tan, R., Ikeuchi, K.: Estimating basis functions for spectral sensitivity of digital cameras. In: Presented at the Meeting on Image Recognition and Understanding (2009) 4. Tominaga, S., Nishi, S., Ohtera, R.: Measurement and estimation of spectral sensitivity functions for mobile phone cameras (in English). Sensors 21(15) (2021) 5. Jiang, J., Liu, D., Gu, J., Susstrunk, S.: What is the space of spectral sensitivity functions for digital color cameras? IEEE Workshop Appl. Comput. Vis., 168–179 (2013) 6. Ji, Y., Kwak, Y., Park, S.M., Kim, Y.L.: Compressive recovery of smartphone RGB spectral sensitivity functions. Opt. Express 29(8), 11947–11961 (2021) 7. Fan, H., Xu, L., Luo, M.R.: Optimized principal component analysis for camera spectral sensitivity estimation. J. Optical Soc. Am. A. 40(8), 1515–1526 (2023) 8. Fan, H., Luo, M.R.: Comparison of LED-based and reflective colour targets for camera spectral sensitivities estimation. Color Imaging Conf. 30(1), 103–108 (2022). https://doi.org/10.2352/ CIC.2022.30.1.20 9. Fan, H., Luo, M.R.: Camera spectral sensitivity estimation based on a display. In: Min, X., Yang, L., Zhang, L., Yan, S. (eds.) Innovative Technologies for Printing and Packaging, pp. 24–30. Springer Nature Singapore, Singapore (2023). https://doi.org/10.1007/978-98119-9024-3_4 10. Hardeberg, J.Y., Brettel, H., Schmitt, F.J.M.: Spectral characterization of electronic cameras. In: Electronic Imaging: Processing, Printing, and Publishing in Color, BELLINGHAM, vol. 3409, pp. 100–109. SPIE (1998) 11. Cheung, V., Westland, S.: Methods for optimal color selection. J. Imaging Sci. Technol. 50(5), 481–488 (2006). https://doi.org/10.2352/J.ImagingSci.Technol.(2006)50:5(481) 12. Shen, H.-L., Zhang, H.-G., Xin, J.H., Shao, S.-J.: Optimal selection of representative colors for spectral reflectance reconstruction in a multispectral imaging system. Appl. Optics 47(13), 2494–2502 (2008) 13. Liang, J., Zhu, Q., Liu, Q., Xiao, K.: “Optimal selection of representative samples for efficient digital camera-based spectra recovery. Color. Res. Appl. 47(1), 107–120 (2022) 14. https://www.image-engineering.de/library/data-and-tools 15. Finlayson, G., Darrodi, M.M., Mackiewicz, M.: Rank-based camera spectral sensitivity estimation. J. Optic. Soc. Am. a-Optics Image Sci. Vis. 33(4), 589–599 (2016) 16. Colorimetry Part 6: CIEDE2000 Color-Difference Formula. ISO/CIE 11664–6:2014(E)

Color Correction for Tongue Digital Imaging Zimo Yan1(B) , Xiao Yang2 , Xiaofang Wang2 , and Yanfang Xu1 1 School of Printing and Packaging Engineer, Beijing Institute of Graphic Communication,

Beijing, China [email protected] 2 Beijing Academy of Printing and Packaging Industrial Technology, Beijing, China

Abstract. In order to improve the color accuracy of tongue digital image, the color correction method was established based on a special color target for color correction of tongue image, and the color response of digital imaging device has been corrected accordingly. Firstly, a one-dimensional lookup table for each monochromatic channel was established which transfers the color of gray blocks in color correction target from imaged RGB to the corresponding sRGB; Then convert the color after one-dimensional transformation to sRGB by color correction matrix. The two-step color correction method achieved accuracy evaluated by CIE DE2000 with the average /maximum value of 1.14/3.23 and 3.01/5.19 for 30 test colors of imaged by two devices. The color correction accuracy of tongue image in traditional Chinese medical has been satisfied. Keywords: Color correction · Digital tongue imaging · Color difference · Traditional Chinese medical

1 Introduction Digital imaging device is crucial for remote inspection diagnosis in TCM (traditional Chinese medicine). Further, the color reproduction of images is a critical quality factor [1]. In medical field, there have been requirements and standards for color resolution and color reproduction of imaging device [2, 3]. Remote tongue image inspection mainly relies on the color of tongue. In order to ensure the accuracy and effectiveness of diagnosis, it is necessary to correct the imaging color to a certain standard. In a digital imaging and display system, the color performance of the display device and imaging device should conform to the same standard. The sRGB color gamut covers the colors required for tongue imaging, and medical displays are often calibrated to sRGB color space [4, 5]. Consequently, tongue imaging should also be corrected to sRGB, that accurately reproduce the tongue color to the screen in TCM inspection. ColorChecker 24 patch classic target has been used for color correction of TCM inspection in research [6], but the specificity to tongue color is not prominent. Another research has selected colors similar to tongue in ColorChecker Digital SG for color correction of tongue [7], which taking into account the colors that tongue imaging © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 30–35, 2024. https://doi.org/10.1007/978-981-99-9955-2_5

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31

focuses on. But if specialized color correction target that focuses on tongue imaging would be designed additionally, it could achieve higher accuracy in color correction results. This study is based on the application requirements of remote tongue inspection in TCM. A specialized color correction target for tongue image is used for establishing corresponding color correction methods. Analysis and correction are carried out on representative digital imaging devices to achieve the color performance of sRGB standard.

2 Correction Method and Experiment The color correction of digital imaging device, which establishing the transformation relationship between image RGB and standard RGB by the color correction target image. Related methods include polynomial regression[8, 9], root- polynomial regression[10], support vector machines[11], neural networks[12, 13], and lookup tables [14]. This study established a color analysis and correction method suitable for TCM tongue imaging based on the dedicated color correction target for tongue, which corrected the initial image to sRGB. The schematic diagram of standard target and tongue target is shown in Fig. 1. The tongue target is designed by ColorSpace Co.ltd.

a. ColorChecker 24 patch classic target

b.Tongue image specialized target

Fig.1. Schematic diagram of target a. ColorChecker 24 patch classic target b. Tongue image specialized target

This The process of color correction will be carried out in CIE color space. The transformation between RGB of device and CIE chrominance depends on sRGB standard. Finally, the transformation model for the RGB before and after correction is recorded. Consequently, compared with traditional color management, this method will not cause the wastage of color, and it can be applied to RGB imaging directly, which is more immediate and more applicable. 2.1 Experimented Devices For comparison, two devices with the same imaging attributes, a scanner and a mobile camera, were selected for the experiment. The scanner is an Epson 12000XL professional scanner with smooth monochromatic tone response, high dynamic response range and

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quality gray balance, which can represent professional medical digital imaging equipment. The Samsung Galaxy S21 mobile phone camera is selected because of the popularity of mobile phones. It is convenient to achieve remote inspection diagnosis by mobile phone which would be the widely used imaging devices currently. 2.2 Color Correction Algorithm Firstly, 1D (one-dimensional) transformation on the RGB of each square in the color target is performed. One-dimensional corresponding relationships between R, G, B values of the six gray colors and corresponding sR, sG, sB values of sRGB are established. Based on this relationship, the RGB values of all colors are transformed and recorded as RGB1 . Secondly, RGB1 is regarded as sRGB, which converted into CIE XYZ chrominance according to the standard relationship of sRGB. Then, establish a 3D (three-dimensional) relationship to CIE XYZ chrominance actually measured by the correction target. Finally, according to the sRGB standard relationship, the corrected CIE XYZ value is converted into sRGB value. The 3D relationship was established using polynomial regression method, and two different polynomial models were used as Model 1 and Model 2 for experiments: Model 1: 1-order 3-term polynomial. Convert the RGB1 of each color in correction target image to the CIE XYZ chrominance (denoted as XYZ1 ) by sRGB standard. Then transfer XYZ1 to the actual CIE XYZ chrominance measured by the color correction target. The conversion process is completed by Eq. (1). q = Mρ

(1)

In Eq. (1), ρ = [X1 Y1 Z1 ]T , q = [XYZ]TsRGB . T represents transposition; M is a 3 × 3 coefficient matrix determined by least square method based on the sampled color data and calculated using Eq. (2). M = QRT (RRT )

−1

(2)

In Eq. (2), R is the Matrix ρ according to XYZ1 of 24 colors in the target image, Q is the matrix q corresponding to the actual CIE XYZ chrominance of the target. Model 2: 2-order 6-term polynomial. Similar to Model 1, XYZ1 is converted into the actual CIE XYZ chrominance of the target, but the difference is that the ρ in Eq. (1) is changed to: ρ = [X1 Y1 Z1 X1 Y1 X1 Z1 Y1 Z1 ]T . M is 3 × 6 coefficient matrix, determined by sampling color values according to Eq. (2). For comparison, ColorChecker 24 patch classic target and tongue specific color correction target were experimented together to establish the color correction relationship. 30 tongue diagnosis focus and frequent colors were selected to form an inspection target in order to test and evaluate the effectiveness of color correction applications, as shown in Fig. 2. The accuracy of color correction inspection is characterized by CIE DE2000 color difference [14].

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33

Fig.2. Inspection target

3 Result and Analysis The professional scanner in this experiment scanned under its own illumination, while the mobile phone camera captured under the illumination with temperature of 5000K in the observation box. The inspection target for tongue imaging is used to evaluate the color correction effect for tongue imaging equipment. The accuracy of each color correction model for the two devices, represented by the average and maximum value of CIE DE2000, is verified by application. The results are shown in Table 1. The initial color difference in the table represents the degree of deviation between the color before correction and actual chrominance of the target, indicating the color performance of the initial imaging. Initial RGB will be used to predict the chrominance before correction depends on sRGB standard. Table 1. Average /maximum ∗ ∗ /E00_max ) (E00_mean Model

color

difference

Scanner

of

inspection

color

imaging

Mobile phone camera

ColorChecker

Tongue target

ColorChecker

Tongue target

1.72/3.33

1.25/2.62

3.98/5.94

3.14/4.79

Model 2

1.19/3.59

1.14/3.23

3.34/5.39

3.01/5.19

Initial color difference

8.58/11.15

Model 1

5.99/8.00

From Table 1, it is obvious that the color difference between sRGB standard of both digital imaging devices after color correction has significantly decreased compared to the initial color difference, indicating that the color correction method has achieved significant improvement for both devices with initial color deviation. Among them, Model 2 has the best effect, reducing the color difference to a level that is difficult for the human eye to detect. Whether scanner or mobile phone camera, and for both color correction models, the color correction accuracy of tongue specific color correction target is higher than that of ColorChecker 24 patch classic target, indicating that in tongue feature colors correction, tongue specific correction target have more advantages than standard target and can better restore the main tongue colors.

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In addition, the color correction accuracy achieved in this paper is compared with representative literature. Among them, reference [9], as a representative of high-precision color correction, has an average and maximum CIE DE2000 of 1.34 and 4.75. The technology used is a self-made color target containing 1331 colors and a subspace adaptive compensation 11-term polynomial method that directly converts to the CIE Lab values from the imaging RGB. References [8] and [10] also achieved similar accuracy, but they also had more than 264 colors target and more than 11 regression relationship terms. By contrast, the color correction method used in this paper has fewer sampling colors, fewer regression terms, and faster calculation speed. Among them, Model 1 is the least 1-order 3-term linear transformation, but it can achieve comparable color correction accuracy. In summary, the color correction method established with the specialized tongue color correction target not only achieves high color correction accuracy in TCM tongue imaging, but also has definite advantages in practical speed.

4 Conclusions Based on the dedicated color target for the characteristic colors of TCM tongue images, a two-step color correction method for application cooperates with its color target has been determined. The imaging color is corrected to sRGB, achieving high-accuracy color correction for TCM tongue imaging, which can restore the actual color of patient tongue and satisfy various needs such as remote video inspection diagnosis in TCM.

References 1. Liu, Y., Gao, L., Song, C.Y.: Analysis of factors affecting the quality of the image obtained by endoscopic observation combined with video-record. Clin. Educ. Gen. Pract. 8(005), 495–497 (2010) 2. National Medical Products Administration. Medical Endoscopes-Rigid Endoscope-Part 1: Optical properties and test methods, YY 0068.1–2008. China Quality and Standards Publishing & Media Co., Ltd. 3. National Medical Products Administration. Medical endoscopes—Video endoscopes, YY/T 1587–2018. China Quality and Standards Publishing & Media Co., Ltd. 4. Meng, Z.Y., Liu, P., Ma, Y.: Discussion on the difference between handheld medical display and traditional medical display. China Med. Device Inf. 27(07), 21–21+25 (2021) 5. www.srgb.com [EB/OL] 6. Wang, H.W.: Research and design of image acquisition and correction for traditional Chinese medicine service system. Guangdong University of Technology (2021) 7. Lu, Y.X.: Deep learning based TCM tongue image color correction, segmentation and sever system. Beijing University of Technology (2019) 8. Hong, G., Luo, M.R., Rhodes, P.A.: A study of digital camera colorimetric characterization based on polynomial modeling. Color. Res. Appl. 26(1), 76–84 (2001) 9. Kong, L.J., Ji, L.L., Jiang, Z.H.M.: Camera colorimetric characterization for printed color quality detection system. Chinese J. Sci. Instrum. 35(12), 2874–2880 (2014) 10. Finlayson, G.D., Mackiewicz, M., Hurlbert, A.: Color correction using root- polynomial regression. IEEE Trans. Image Process. 24(5), 1460–1470 (2015)

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11. Song, J.L.: Research on technology of tongue image calibration and its result evaluation. Harbin Institute of Technology (2008) 12. Xinwu, L.: A new color correction model for based on BP neural network. Int. J. Adv. Inf. Sci. Serv. Sci. 3(5), 72–78 (2011) 13. Jiang, F.F., Xu, L.P., Zheng, L.Y.: Color characterization for digital camera based on BP neural network. Packag. Eng. 33(05), 107–110+118 (2012) 14. Ma, M.J.: Color correction of digital image based on three-dimensional look-up table. Beijing University of Technology (2009)

Brief Analysis of the Different Tones of Spot Colors in Digital Printing Wenjun Guan and Buyan Li(B) Printing Training Center, Shanghai Publishing and Printing College, Shanghai, China [email protected]

Abstract. Purposes: In digital printing, four colors are used to simulate spot colors for printing, when the spot color level changes, the color matching ratio of four colors will change, not just the change of the dot, which will directly affect the hue value, that is, there will be color deviation. This paper will use the method of spot color matching to output the gradual change of spot color and analyze the change of their hue value. Method: Under the condition of ideal color state of the equipment, the output of four-color and spot color matching is carried out, the data is measured by LCH color space, the theoretical value is obtained from the software, and the actual value is measured by Xrite eXact spectrometer and analyzed. Result: The smaller the color difference value after spot color matching, the hue value H is closer to the theoretical value, and the hue of different order is stable. When the matching effect of spot color is not good, the color Angle of different order fluctuates greatly, and the color is gradually discolored and unstable. Conclusion: When the spot color is applied in a gradual gradient, it is necessary to avoid the tone range of 10%-30% as far as possible, and the probability of jumping in the hue value is high, which is easy to produce color bias. Keywords: Digital Printing · Spot Color Matching · Hue

1 Introduction In traditional printing, spot colors can often achieve color effects that cannot be presented by four-color inks, and can also solve practical problems in printing, such as improving the uniformity of large areas of color blocks, or getting more detailed graphics and so on. The application of spot colors can also help enterprises save costs while achieving better color effects. In recent decades, with the rapid development of digital printing, the application of spot color in the field of digital printing has become more and more, especially after digital printing has entered the field of packaging and printing, where spot color is used most, the printing and proofing of packaging boxes cannot be separated from the application of spot color in digital printing. In order to enrich the color of printed matter and increase the picture level of products, more and more products begin to apply spot colors to different levels and levels.

© The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 36–44, 2024. https://doi.org/10.1007/978-981-99-9955-2_6

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2 Research Purpose and Current Research Situation 2.1 Research Purpose With the rich printing products, the application of spot color is more and more diversified. For traditional printing, spot color printing can be printed as a single color, no matter how the tone of the color changes, its hue will not be deviated. However, for digital printing, because four colors are used to simulate spot colors, when the spot color level tone changes, the color matching ratio of four colors will change, which will directly affect the hue value and color deviation. This paper will use the method of spot color matching to analyze the hue change of the output of different order tones of spot color and explore its changing rule. 2.2 Current Research Situation Color is undoubtedly one of the most important indicators to judge the color quality of a printed matter, usually through the detection of spectral data to control the printing hue [1], also through software correction or process control are currently more common color processing methods [2], but this method is not suitable for spot color printing due to the lack of standardization. The printing application of spot colors is very common in the field of printing and packaging. In offset printing, after the technician mixes the original color ink into the spot color ink in a certain proportion, the printing can be carried out in the way of the original color ink. Generally, the LCH color space is used to assist the ink mixing, because the hue value H can better help the technician find the color Angle and improve the color accuracy of the spot ink [3]. However, the products using digital printing often have field spot color effect and customers are not satisfied or spot color deviation occurs when the spot color level tone changes [4]. At present, Lab and LCH are commonly used for spot color, and the Lab value can be converted to LCH value to more intuitively represent the color properties [5]. Spot color applications in the digital printing process can be roughly divided into the following three types: (1) Directly use the special color ink configured by the equipment, commonly known as the "fifth color". Major digital printing equipment manufacturers are currently beginning to develop special inks suitable for their own models, and special inks are usually colors that cannot be achieved by the existing four-color printing inks of the equipment, such as white, transparent color, fluorescent color, etc. (2) Through the RIP in the printing process, the spot color information in the file will be simulated by the default color conversion method in the process and then output. This way is simple and fast, and it is a good choice for junior operators of digital printers, but the disadvantage is that the color difference is not easy to control. (3) Use the spot color matching method in the process [6]. This approach is most common for digital printing with limited types and quantities of spot inks, which is free from the constraints of color management and ICC property files, and simulates the spot color to be printed by using the four-color toner of the digital printing device itself.

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3 Hue Test and Analysis of Different Tones 3.1 Instructions In LCH color space, the H value can reflect the color hue, and the degree of color deviation of the color can be seen more intuitively from the numerical value [7]. This experiment will test and analyze the hue of different tones after matching the printing color and spot color of the equipment. The spot color target selected for the test is the internationally common PANTONE color, and the international class of paper coated paper is used as the test medium. The test is based on LCH color space, L is for Lightness; C stands for Chroma; H stands for Hue, as can be seen from the Fig. 1, hue is the hue Angle, each color has a unique hue value, it is a value unrelated to brightness and saturation. But in digital printing, because of the four-color simulation, the three will affect each other.

Fig.1. LCH color space

3.2 Test Preparation The test preparation included: (a) (b) (c) (d) (e)

Ambient temperature and humidity: Temperature: 25°C, humidity 55%. Equipment: a digital electrostatic printing machine. Paper: 157g/m2 coated paper. PANTONE color card: Solid Coated. Instruments: EFI ES3000 color calibration instrument, Xrite eXact spectrometer density instrument.

3.3 Test Steps 3.3.1 Equipment Preparation and Warm up After the ambient temperature and humidity are stabilized, the digital press should be warmed up to ensure that the equipment is in a stable state, and the EFI ES3000 color calibrator is used to calibrate the equipment to achieve its best color state.

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3.3.2 Output Test Graph Make and output test graph of different tones (10%-100%) of cyan, magenta, yellow and spot colors. Select four different bands of color, red, yellow, blue and green, and select a spot color in each color. Use spot color matching in the process to output the test graph (Fig. 2 show this).

Fig.2. Test graph

3.3.3 Data Measurement Before the test, the four colors were converted into the Lab color space independent of the device in Photoshop, and the Lab value was obtained from the software. Then the theoretical hue Angle and saturation were obtained √ through the conversion formulas of Lab and LCH color space: H = arctg ab and C = (A2 + B2 ). Spot color matching is based on four-color mixing to simulate, because black does not belong to the hue, only reflected in the lightness, so the experiment only for the cyan, magenta, yellow monochromatic order of the measurement and analysis. The measurement results are as Table 1 and Table 2. Table 1. Cyan LCH (theoretical) Tone

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

L

96

91

87

83

78

74

70

65

60

56

C

7.2

13.6

19.4

26.1

33

39.7

46

53.8

61.6

69.2

H

236.3

234

235.5

237.5

234.9

236.3

235.6

234.8

234.2

232.6

It can be seen from Table 1 and Table 2 that the change of lightness and chroma is linear with the change of the tone. The lightness value in Table 3 is generally high and the fluctuation is small, which is related to the spectral properties of the yellow toner

40

W. Guan and B. Li Table 2. Magenta LCH (theoretical)

Tone

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

L

95

90

85

80

75

69

64

59

54

48

C

7.3

14.3

20.4

27.5

36.5

44.4

53.5

62.3

72.2

84.1

H

344.1

347.9

348.7

349.5

350.5

352.2

352.5

354.5

356

357.3

itself. From the H values in the above three tables, we can get that when each color changes in order, the maximum and minimum values of the H value does not exceed 5% Table 3. Yellow LCH (theoretical) Tone

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

L

99

99

98

97

97

96

96

96

95

95

C

9.2

17.3

26.3

45.3

46.4

56.3

67.3

79.3

92.3

106.3

H

102.5

100

98.7

96.3

97.4

96.1

95.1

95.1

94.4

94.3

LCH of Different Order Tones of Cyan, Magenta and Yellow As can be seen from Table 4 and Table 5, cyan and magenta have great changes in hue angle, ranging from 0 to 360, and the hue angle offset of cyan reaches 7.9% and magenta reaches 13.4%. As can be seen from Tab.6, there is an obvious numerical jump in the position of the 10% order tone, which is related to the property of the yellow ink itself. Generally, the brightness is too high and the float is small, which will cause the error of the measurement data. One of the reasons of the error is the accuracy that the device can currently achieve. In addition to the 10% order tone, the hue angle offset of the remaining order tone is very small and almost unchanged. Table 4. Cyan LCH Tone 10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

L

89.13

85.94

82.41

78.36 73.86

71.11

65.57

60.01

56.59

51.20

C

9.25

14.32

19.29

24.73 30.47

33.85

40.39

48.57

53.02

60.46

H

264.3

253.7

248.1

245.7

243

242.8

239.8

240.4

237.2

235.8

LCH of Different Tones Based on Spot Color Matching On the Solid Coated color card of PANTONE, four representative colors near 0 (360) degrees, 90 degrees, 180 degrees, and 270 degrees in the hue ring are selected: PANTONE

Brief Analysis of the Different Tones of Spot Colors

41

Table 5. Magenta LCH Tone 10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

L

88.11

84.40

79.37

74.32

70.03

64.22

59.30

54.60

48.59

46.05

C

9.8

15.2

19.11

26.52

31.98

40.09

48.66

57.27

68.96

72.56

H

309.5

323.8

337.3

340.5

345.6

349.5

351.6

353.3

355.2

357.6

Table 6. Yellow LCH Tone

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

L

91.07

90.36

89.35

87.92

87.96

87.15

86.34

85.86

85.71

85.60

5.88

13.84

25.56

26.60

36.27

46.94

57.07

71.55

85.94

95.6

95.8

95.7

96.0

95.7

95.6

95.4

95.3

C H

0.39 14.2

94.5

201 C; PANTONE 110 C; PANTONE 287 C; PANTONE 356 C. The spot color matching method in the process is used for color processing. The Lab values before and after three times of matching processing are shown in Fig. 3 and Fig. 4 (Fig. 3 and Fig. 4 are the Chinese interface of the software, and the research only refers to the data in the red box). The Lab of spot color deserves to be optimized, which can help the four colors to better simulate and match.

Fig.3. Lab before color matching

Fig.4. Lab after color matching

The final E values: (a) PANTONE 201 C: 1.05, (b) PANTONE 110 C: 1.60, (c) PANTONE 287 C: 3.44, (d) PANTONE 356 C: 1.05. Except PANTONE 287 C, the color difference value is less than 3, and the color matching effect is satisfactory. The LCH values obtained after color tracing are shown in Table 7, Table 8, Table 9 and Table 10. In Table 7, Table 8, and Table 9, the hue angle value jumps at the positions of the 10% tone, because there are more yellow toner in PANTONE 201C, PANTONE 110C, and PANTONE 356 C, which corresponds to the results of the monochrome toner test. Spot color matching involves the participation of two or more toners, and according to the principle of color subtraction, the lightness is generally low and Chroma will also be low.

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W. Guan and B. Li Table 7. PANTONE 201 C LCH

Tone L C H

10% 79.8 7.55 356.0

20%

30%

40%

50%

60%

70%

80%

90%

100%

73.58

67.91

63.32

57.63

53.22

48.32

42.83

38.64

35.52

12.77

18.32

23.5

29.44

35.27

40.88

47.10

52.17

54.27

13.38

21.72

22.53

20.61

20.99

21.42

21.86

22.65

26.06

Table 8. PANTONE 110 C LCH Tone

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

L

88.38

86.51

82.64

80.76

78.45

76.62

74.45

72.76

71.04

69.03

C

2.85

9.82

15.51

19.95

25.23

32.98

39.9

49.18

59.81

71.43

H

49.33

81.06

84.78

83.99

83.53

84.1

83.89

84.68

84.64

84.43

80%

90%

100%

Table 9. PANTONE 287 C LCH Tone 10%

20%

30%

40%

50%

60%

70%

L

85.11

78.45

71.01

63.95

56.99

51.98

46.67

40.19

34.51

26.15

C

11.71

15.45

19.78

23.40

26.91

29.25

32.40

35.31

39.48

43.57

H

293.2

290.3

286.5

287.7

289.9

290.1

289.2

286.5

281.9

276.7

80%

90%

100%

Table 10. PANTONE 356 C LCH Tone 10%

20%

30%

40%

50%

60%

70%

L

85.43

79.98

74.52

70.87

66.45

62.90

58.77

53.60

47.98

41.59

C

2.94

6.84

10.66

14.37

18.45

23.15

27.93

33.00

39.45

50.20

H

194.7

156.9

161.3

159.2

158.4

150.1

146.3

148.0

148.9

152.2

4 Analysis It can be seen from Fig. 5 that the actual hue values of magenta and yellow have a high coincidence degree with the theoretical values in the dark tone area, which means that more accurate hue values can be obtained. The hue angle of cyan is greater than the theoretical value, indicating that the cyan toner of the digital printer is slightly off-color. The brightening area of the three colors has a large hue angle offset, especially the yellow has an obvious jump, which is closely related to the lightness value, which is easy to cause the deviation in hue detection.

Brief Analysis of the Different Tones of Spot Colors

(a) Cyan

(b) Magenta

43

(c) Yellow

Fig.5. Comparison of the actual H value (blue line) with the measured H value (red line) (a) Cyan (b) Magenta (c) Yellow

As can be seen from Fig. 6, the three colors with better E value are: PANTONE 201 C, PANTONE 110 C, and PANTONE 356 C all have a high coincidence degree at 30% to 100% of the hue angle, but there is still a numerical jump at the 10% position, because these three colors contain a large amount of yellow, which is affected by the actual color of yellow. The E value of PANTONE 287 C is 3.44 in spot color matching, which does not reach a satisfactory color difference value. The actual hue angle directly fluctuates significantly with the theoretical value, but at 90% order tones, the hue conforms to the theoretical value.

(a) PANTONE 201 C

(b) PANTONE 110 C

(c) PANTONE 287 C

(d) PANTONE 356 C

Fig.6. Comparison of the actual H value (blue line) and measured H value (red line)

5 Conclusion After the digital printing machine is warmed up and the color calibration is finished, the spot color matching is performed on the spot color that needs to be printed in the process, and this process can ensure that the spot color simulated by four colors (the

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spot color does not exceed the printing color gamut of the digital printing machine) is satisfactory. Through the test, we can know: (a) The smaller E value, the H value is also closer to the theoretical value, and the hue of different tones is stable. (b) Spot color is prone to jump in the hue angle value in the bright-tone area, and color bias is prone to appear in the bright-tone area. (c) If the spot color exceeds the color gamut of the printer or the color matching effect is poor, the field hue angle deviates from the theoretical hue angle, and the hue angle of different tones fluctuates greatly, and the gradual color deviation is prone to color instability. (d) Since printing is the color superposition of toner or ink, according to the color subtraction method, the reduction in brightness will lead to visual color bias. To sum up, for spot color gradient, in order to obtain a better and stable spot color level tone, it is necessary to carry out color matching under the condition of good color state of the equipment to obtain a hue angle close to the theoretical value. In the gradual application of spot color, try to avoid 10%-30% order tone, easy to appear color value jump, that is, color bias.

References 1. Deng, T., Wenting, F.: Digital proofing custom spot color matching method. Pack. J. 2019(04), 90–94 (2019) 2. Hao, Q., Chen, X.: Discussion on the method of color correction of partial manuscript. Guangdong Printing 1995(04), 19–21 (1995) 3. Zhu, X.: Discussion on the difference between color space CIELAB and CIELCH in the preparation of spot color ink. Guangdong Printing 2022(04), 46–49 (2022) 4. Yang, Y.: Digital printing spot color problem and solution. Digital Printing 2017(06), 32–34 (2017) 5. Liu, D.: LAB and LCH color space and application. Print Today 2002(10), 53–56 (2002) 6. Duan, Z., Zhang, J.: Study on control measures of printing color of cigarette pack with same color spectrum. Printing Technol. 2020(03), 26–28 (2020) 7. Guo, S.: Research on geometric color matching method based on 24-hue ring. J. Jingdezhen Univ. 2022(06), 36–39 (2022)

Evaluation of Color Measurement Geometries for Optically Variable Inks Ziwen Wei, Yu Liu(B) , Yuetong Shen, Xuping Gong, Xiu Li, and Min Huang Printing and Packaging Engineering, Beijing Institute of Graphic Communication, Beijing, China [email protected]

Abstract. Optically Variable Inks (OVI) holds significant value and finds extensive application in the domain of anti-counterfeit printing. To evaluate the effectiveness of the measurement geometries prescribed by existing standards for evaluating the color-shifting feature of OVI, the experiment employed an X-Rite MAT12 multi-angle spectrophotometer to measure and analyze the chromatic and spectral characteristics of 10 different OVI samples in 12 geometries. The findings indicate that a decrease in the aspecular angle results in higher saturation of OVI. Additionally, when the aspecular angle is ±15°, an increase in the illumination angle leads to notable changes in the hue angle of OVI. The measurement geometries of r45as-15 and r15as15 find the highest saturation and the most extensive range of hue variations for the OVI samples, exhibiting color changes that align with the manufacturer’s labels. However, when the samples were tested using the geometries specified in GB/T17001.7-2023, the optimal color-shifting effect of the ink was not evident. Keywords: Optically Variable Inks · Measurement geometries · Color shifting · Chromaticity Characteristics · Spectral Characteristics

1 Introduction Optically Variable Inks (OVI) are printing inks constituted by multi-layer interference filters as their pigment components. When illuminated by natural light, objects printed with this ink present a distinctive color shift with the change of viewing angles [1]. Leveraging this unique feature, it serves as a protective measure against forgery in high-value documents, widely used in the printing of banknotes, confidential files, and ID cards. In production workflows, compared to visual inspection, employing color measurements to quantify the color-shifting effect of OVI is essential for its print quality control. Existing standards propose a range of geometric conditions for color measurements of gonioapparent objects. For instance, ASTM E2539-14 recommends the use of four specific geometric conditions (r45as-15, r45as15, r15as-15, r15as15) for measuring interference pigments [2]. GB/T17001.7-2023 standard prescribes repeated measurements

© The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 45–51, 2024. https://doi.org/10.1007/978-981-99-9955-2_7

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at an illumination angle of 45° and observation angles of 30° and 90° to assess the color-shifting characteristics of optically variable inks [3]. Numbers of studies have been conducted using these prescribed measurement geometries and methodologies. E. Chorro et al. employed the Datacolor FX10 device to analyze the visual and optical anisotropy of metallic and pearlescent samples, conducting measurements under 10 geometric conditions in compliance with international standards [4]. Eric Kirchner et al. utilized three multi-angle spectrophotometers and follows the ASTM E2539-08 norm for in-plane measurement geometries to explain colorimetric characteristics of effect coatings [5]. Esther Perales et al. evaluated the consistency of five multi-angle spectrophotometers, utilizing the five measurement geometries according to ASTM E2214-08 [6]. Omar Gómez et al. used a BYK-mac multi-angle spectrophotometer to evaluate automotive samples under six measurement geometries, assessing the correlation between psychophysical experimental outcomes and device readings [7]. Werner validated discrepancies often exist between visual assessment and instrumental assessment, and proposed a visual evaluation method [8].Chen, Wang et al. designed a color measurement device for OVI based on geometries of r22.5as22.5 and r45as-22.5. They believe that the CIE L* a* b* chromaticity values at these two angles can characterize the color change characteristics [9]. The existing OVI color measurement methods have many geometries and don’t correspond to observation results. To determine a simple and effective OVI color measurement method, this study utilizes the X-Rite MA-T12 multi-angle spectrophotometer to measure 10 OVI samples supplied by different manufactures.

2 Experimental 2.1 Instrument and Geometries The X-Rite MA-T12 multi-angle spectrophotometer, with 12 spectral measurement angles, was employed in this study to perform colorimetric measurements on the samples. This instrument satisfies the measurement geometries specified in ASTM E2539-14 and GB/T17001.7-2023. It enables rapid and accurate assessment and validation of color, gloss, roughness, and texture characteristics of complex surfaces, exhibiting high levels of repeatability and reproducibility. This study will use the notation prescribed in ASTM E2539-14. The 10 measurement geometries used in the study are shown in Table 1. 2.2 Test Samples Ten test samples were printed using OVI provided by different manufacturers, labeled No.1–No.10. The manufacturers have already named the color-shifting effects of these samples, including green-purple, blue-purple, yellow green-blue etc.

15°

−15°

r45as-15

Aspecular Angle

Designation

r45as15

45°

45°

Illumination Angle

r45as25

25°

45°

r45as45

45°

45°

r45as75

75°

45°

r45as110

110°

45°

r15as-45

−45°

15°

r15as-30

−30°

15°

Table 1. Measurement geometries used in the experiment

r15as-15

−15°

15°

r15as15

15°

15°

r15as45

45°

15°

r15as80

80°

15°

Evaluation of Color Measurement Geometries 47

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3 Results and Discussion 3.1 Spectral Power Distributions Figure 1 depicts the relative spectral power distributions (SPDs) of the 10 samples, obtained by D65 light source using the X-Rite MA-T12 spectrophotometer in 12 geometries. Substantial variation is noted in the spectral energy for different geometries. Specifically, Sample No.8 achieved a relative spectral energy of 400% for the geometry r45as15. The highest energy levels across all samples were consistently recorded in the geometries of r45as-15, r45as15, r15as15, and r15as-15. Notably, the spectral energy levels of r45as-15 geometries were higher than other geometries. Spectral energy typically fell below 100% with larger aspecular angles. In addition, the SPDs of Samples No.1, No.6, and No.10 showed considerable peak wavelength differences for r45as-15 geometry compared to the rest. The differences in SPDs of 12 geometries are the cause of color shifts in these OVI samples from different observation angles.

Fig. 1. Relative spectral power distributions of ten samples obtained using D65 light source with X-Rite MA-T12 in 12 geometries

3.2 Colorimetric Values To analyze the colorimetric variation of OVI for different measurement geometries and to establish the optimal measurement geometry, the chromaticites of samples No.1–No.10

Evaluation of Color Measurement Geometries

49

measured at different geometries were calculated based on the D65 /10° and plotted in CIE 1976 a* b* diagrams, as illustrated in Fig. 2. A clear observation of colorimetric values shifts with changing measurement geometries can be seen across 10 test samples, which aligns with the colorimetric properties of OVI as a gonioapparent material. In Fig. 2a, when the illumination angle is set to 45°, the samples measured at aspecular angles of ±15° show higher saturation compared to the rest. As the aspecular angle increases, the overall sample saturation reduces. Thus, we can confirm that the aspecular angle is a crucial factor influencing the saturation change in OVI, corroborating the decreasing trend of the spectral power distribution level depicted in Fig. 1. In Fig. 2 (b), with the aspecular angle set to ±15°, a considerable hue shift occurs as the illumination angle changes from 45° to 15°. The largest hue angle difference is observed between the r45as-15 and r15as15 geometries. Moreover, it is worth noting that the r45as45 and r45as-15 geometries, utilized in GB/T17001.7-2003 to represent the color-shifting effect of OVI, did not capture the optimal hue shift range for the samples tested in this experiment.

Fig. 2. Colorimetric values of ten samples measured at different geometries using D65 /10° standards, plotted in CIE 1976 a* b* diagrams

To verify the correlation between the colorimetric values of r45as-15, r15as15, r45as45, r15as-45 geometries and the corresponding color-shifting effects under these illuminating and observation angles, a Canon EOS 760D camera was employed (exposure setting of 800, and a resolution of 6000 × 4000). The camera was placed at a distance of 40 cm from the samples. Illumination was provided by the integrated light source of an iPhone 8 Plus, adjusted to its dimmest setting, angled at 45° and 15° with respect to the normal line. Each sample was photographed in the normal and 60° with respect to the normal line directions, showing the color-shifting effects of OVI in the r45as15, r15as15, r45as45, r15as-45 geometries and shown in Table 2. The color-shifting of r45as45 and r45as-15 geometries recommended by GB/T 17001.7–2003 are relatively small. And saturation of r45as45 geometry is low. The color-shifting effects captured

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in r45as-15, r15as15 geometries align well with the color-changing labels ascribed by the manufacturers for OVI samples, and they also demonstrate considerable consistency with the hue change results depicted in Fig. 2. Table 2. Photographs of OVI samples in r45as-15, r15as15, r45as45, r15as-45 geometries No.

Samples

r15as15 r45as45 r15as-45 r45as-15 No.

(green1

purple)

orange)

r15as15 r45as45 r15as-45 r45as-15

(silver6 green)

(green2

Samples

(brownish 7 red-green )

(green(rose red3

turquoise

8 gold)

blue) (blue4

purple)

(yellow 9 green-blue)

(red-gold) 5

(grass 10

greenpurple)

4 Conclusions Based on the analysis of the SPDs and colorimetric data obtained from 10 OVI samples using the X-Rite MA-T12 multi-angle spectrophotometer, following two conclusions can be made: 1) The saturation of OVI ink increases with the decrease of the aspecular angle in the measurement geometries. Geometriesat aspecular angles of ±15° caused high saturation. 2) Higher saturation and larger hue changes were observed in OVI samples measured for r45as-15 and r15as15 geometries, and these changes corresponded with the manufacturer’s labeling. In contrast, the optimal color-shifting effect was not observed in the samples for the measurement geometries customized for OVI in GB/T17001.7-2023 used in this experiment.

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References 1. Degott, P.: Optically Variable Inks (OVI): versatility in formulation and usage. In: Optical Security and Counterfeit Deterrence Techniques III, vol. 3973. SPIE (2000) 2. ASTM Standards. Standard test method for multiangle color measurement of interference pigments: E2539–14 (2021) 3. National Technical Committee on Anti-counterfeiting of Standardization Administration of China. Anti-counterfeiting printing ink Part seven: optical variable anti-counterfeiting ink: GB/T17001.7-2023. Standards Press of China, Beijing (2023) 4. Chorro, E., et al.: Colorimetric and spectral evaluation of the optical anisotropy of metallic and pearlescent samples. J. Mod. Opt. 56(13), 1457–1465 (2009) 5. Kirchner, E., Cramer, W.: Making sense of measurement geometries for multi-angle spectrophotometers. Color. Res. Appl. 37(3), 186–198 (2012) 6. Perales, E., et al.: Reproducibility comparison among multiangle spectrophotometers. Color. Res. Appl. 38(3), 160–167 (2013) 7. Gómez, O., et al.: Visual and instrumental assessments of color differences in automotive coatings. Color. Res. Appl. 41(4), 384–391 (2016) 8. Cramer, W.R.: Visual and instrumental assessment of interference pigments. Color. Res. Appl. 47(1), 5–12 (2022) 9. Chen, B., Wang, H.B., et al.: Method of measuring color characteristics of optical variable ink: ZL2000115502 (2003)

Image Processing Techniques

Unsupervised Low-Light Image Enhancement Algorithm Based on Prior Information Cong Liu and Yigang Wang(B) College of Media and Design, Hangzhou Dianzi University, Zhejiang, China [email protected]

Abstract. Images captured in dimly illuminated surroundings often suffer from low contrast and severe loss of details, which directly affect the accuracy of subsequent image classification, recognition, and detection tasks. This paper addresses the challenges of low-light image enhancement, which relies on real data training and the insufficient availability of effective information in low-light images. An unsupervised low-light image enhancement algorithm, based on prior information, is proposed by us. By performing histogram equalization on the preprocessed images before network training, hidden information in the images is obtained. The optimization of initialization information is achieved by extracting the reflectance and illumination maps of the low-light images, which preserves the relative structural integrity of the images and improves the brightness restoration effect. The experimental outcomes validate the efficacy of the proposed algorithm in restoring brightness and reproducing natural colors in images. In comparison to other algorithms, it demonstrates superior performance on the LOL dataset in terms of peak signal-to-noise ratio (PSNR), structural similarity index (SSIM), and natural image quality evaluation metrics (NIQE). Specifically, it achieves improvements of 1.433 dB, 0.040, and 1.285, respectively. Keyword: Image Enhancement · Prior Information · Low Illumination

1 Introduction Low-light scenes often result in low image contrast, desaturated colors, limited dynamic range, and loss of important visual information in natural environments. These issues subsequently degrade the performance of image recognition, classification, and detection, necessitating the development of low-light image enhancement techniques to meet the demands of visual interpretation. Currently, deep learning methods are primarily employed for low-light image enhancement, primarily leveraging the GAN (Generative Adversarial Network) mechanism [1, 2] and adaptive fitting of implicit priors in optimization modules [3]. These approaches extract the necessary information from large-scale unpaired image data and learn from reference-free loss functions. However, they suffer from limitations such as dependence on paired images and high requirements for effective information initialization in unsupervised learning. In this study, building upon the brightness enhancement network [4], An unsupervised low-light image enhancement © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 55–61, 2024. https://doi.org/10.1007/978-981-99-9955-2_8

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algorithm, based on prior information, is proposed by us. We design a novel brightness enhancement model that fully utilizes the input image data and extracted feature maps through a designed prior network. This approach enables us to obtain richer information regarding image dynamic range, reflectance, and texture, thereby enhancing the effectiveness of image enhancement and brightness detail restoration.

2 Unsupervised Low-Light Image Enhancement Algorithm Based on Prior Information The algorithm model for unsupervised low-light image enhancement based on prior information is illustrated in Fig. 1.

Fig. 1. Algorithm model of unsupervised low-light image enhancement based on prior information.

2.1 Prior Network Module The prior network module, proposed in this paper, is depicted in Fig. 2.

Fig. 2. Prior network architecture

To address the issue of insufficient effective information in low-light images, this study employs an improved histogram equalization method enhanced by VGG feature maps [5, 6] for feature extraction. Additionally, a fully convolutional network is utilized to enrich the learning of initialization information [7]. This network has the capability to adaptively learn the illumination and reflectance. This paper addresses the issue of lacking real image samples to obtain the two feature components close to the original low-light image. To tackle this, the paper proposes an

Unsupervised Low-Light Image Enhancement Algorithm Based on Prior Information

57

approach using illumination initialization based on normal illumination images. The loss function is defined as follows:   (c)2 Linit = λˆ wˆ − max ρˆF + e−η∇ xˆ · ∇ wˆ + F(ρ) − F(X )22 (1) c∈{R,G,B}

where  · F and  · 1 represent the F -norm and l1 -norm, respectively. λˆ and η are hyperparameters. c ∈ {R, G, B} represents the RGB channels, ∇(·) denotes gradient computation, and F(·) indicates the feature maps extracted from the pre-trained VGG19 model on ImageNet. The loss function computes the difference between the feature maps of the output reflectance image and the input image. 2.2 Brightness Detail Restoration Module The brightness detail restoration module decomposes the low-light image into a reflectance map and an illumination map and enhances the image’s brightness based on the Retinex [8]. Its natural modeling is represented by Eq. (2): X =ρW

(2)

where X represents the input low-light image, ρ represents the reflectance map, W represents the illumination map, and  denotes element-wise multiplication. To restore brightness details, an improved brightness enhancement network is employed to recover the illumination of low-light images. Based on the Retinex theory, the network decomposes the image into two components: illumination and reflectance. This paper employs the LeakyReLU activation function, which can reduce the phenomenon of neuron death, to improve the brightness enhancement network. f (x) = max(0.01x, x)

(3)

where x represents the output from the upper layers of the network. The LeakyReLU activation function is utilized in the network, where a small initialization value is assigned to the LeakyReLU neurons. Consequently, it enables the adequate restoration of the illumination in low-light images, thereby achieving the goal of brightness detail recovery (Fig. 3).

Fig. 3. Network layer structure

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It is necessary to reconstruct the loss function to fuse the output reflectance map and illumination map after decomposing the image into the reflectance map and the illumination map, ensuring the quality of the generated image. The loss function is defined as follows: Lrecon = min Xˆ − ρˆ · wˆ 1 ρ, ˆ wˆ

(4)

In the equation, Xˆ represents the normal light image, ρˆ represents the reflectance ˆ represents the illumination map. The loss function is used to guide the map of Xˆ , and W network optimization and ensure that the generated image has a minimal difference in illumination compared to the normal light image.

3 Experimental Results and Analysis This study utilized the LOL-datasets with 500 paired images as the training dataset. Our algorithm only uses the low light part for training. 3.1 Objective Evaluation Index of Model Performance The performance evaluation of the algorithm in this study was based on objective assessment metrics, including PSNR, SSIM, and NIQE. These metrics were calculated using the following formulas (Eqs. 5, 6, and 7) respectively.  2  2N − 1 PSNR = 10 · log10 (5) MSE In the mentioned formulas, N represents the number of bits used to store each pixel, and MSE refers to the mean squared error of the image.    2μx μy + C1 2σxy + C2  (6) SSIM (x, y) =  μ2x + μ2y + C1 σx2 + σy2 + C2 In the given formulas, x and y represent the two images being compared, μx and , μy are the mean values of x and y, σx and σy are the standard deviations of x and y, and σxy represents the covariance between x and y. C1 and C2 are positive constants.

o1 + o2 −1 ) (e1 − e2 )) NIQEe1 , e2 , o1 , o2 = ((e1 − e2 )T ( (7) 2 Within the provided formula, the mean vectors and covariance matrices of the natural MVG (Multivariate Gaussian) model and the distorted image MVG model are denoted by e1 , e2 , o1 , and o2 , respectively.

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3.2 Analysis of Model Experiment Results The experimental evaluation of the compared models, Lime (Low-light Image Enhancement) [9], NPE (Naturalness Preserved Enhancement), RUAS (Retinex Unrolling Architecture Search), EnlightenGAN (EGAN), and ZeroDCE (Zero-Reference Deep Curve Estimation), was conducted from both objective and subjective perspectives. The evaluation results are as follows: Objective Evaluation. Table 1 presents the experimental results comparing the proposed algorithm with Lime, NPE, RUAS, EnlightenGAN, and ZeroDCE. It can be observed that the proposed algorithm outperforms the other methods. Compared to the second-best RUAS algorithm, the proposed algorithm achieves improvements of 1.433 dB in PSNR, 0.040 in SSIM, and 1.285 in NIQE. Table 1. Performance comparison on datasets Measure

LIME

NPE

RUAS

EGAN

ZeroDCE

Our

PSNR↑

16.74

16.97

18.23

17.48

14.86

19.66

SSIM↑

0.444

0.482

0.717

0.654

0.562

0.757

NIQE↓

9.779

9.788

6.340

5.238

8.811

5.055

Subjective Evaluation. Figure 4 depicts the experimental results of the proposed algorithm compared to Lime, NPE, RUAS, EnlightenGAN, and ZeroDCE. After enhancing the images using the proposed model, there is a noticeable improvement in image quality. The brightness is appropriately adjusted, there are fewer artifacts, and the details are preserved more accurately. Particularly, in terms of fine details, such as the smoothness of cabinet surfaces and the increased reflection details on metal bowls, the proposed algorithm exhibits a more natural and visually appealing effect.

3.3 Analysis of the Efficiency of the Method To examine the effectiveness of the algorithm on out-of-dataset samples, this study employed five images from the EGAN dataset and enhanced them using the proposed algorithm. The NIQE values before and after enhancement are presented in Table 2. The comparative results indicate that the algorithm exhibits a certain level of perceptual understanding and effectiveness when applied to images from outside the dataset. Figure 5 presents a visual comparison of the images before and after enhancement. Based on subjective evaluations, it is evident that the proposed algorithm demonstrates good effectiveness in enhancing out-of-dataset images. It restores the brightness of the images while preserving their structural integrity.

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Source

EGAN

LIME

NPE

RUAS

ZeroDCE

Ours

Ground Truth

Fig. 4. Comparison of sample enhancement results for LOL dataset

Table 2. NIQE comparison before and after enhancement Type

Image_1

Image_2

Image_3

Image_4

Image_5

Source

9.4396

5.7256

6.9990

8.0333

9.8014

Enhanced

6.2482

4.8568

4.3670

6.8001

6.8812

Fig. 5. Image enhancement before and after contrast

4 Conclusion We have introduced a low-light image enhancement algorithm based on prior information. By introducing a prior network module, it fully extracts and utilizes the hidden information in low-light images, addressing the limitations of relying on real data training and insufficient effective information in low-light images for enhancement. By leveraging prior information, the proposed algorithm effectively achieves illumination enhancement and preserves intricate details, thereby mitigating the reliance on empirical

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data for training purposes. It provides valuable insights for research on low-light image enhancement and improves the feasibility of practical applications in low-light image enhancement engineering. Acknowledgements. This work was supported by Zhejiang Provincial Science and Technology Program in China (2021C03137).

References 1. Yifan, J., Xinyu, G., Ding, L., et al.: EnlightenGAN: deep light enhancement without paired supervision. Comput. Res. Repository 30(1), 2340–2349 (2021) 2. Guo, C., Li, C., Guo, J., et al.: Zero-reference deep curve estimation for low-light image enhancement. In: Computer Vision and Pattern Recognition, pp. 1777–1786 (2020) 3. Qiming, H., Xiaojie, G.: Low-light Image enhancement via breaking down the darkness. arXiv preprint arXiv:2111.15557 (2021) 4. Zhang, Y., Di, X., Zhang, B., Wang, C.: Self-supervised image enhancement network: training with low light images only. arXiv preprint arXiv:2002.11300 (2020) 5. Justin, J., Alexandre, A., Fei-Fei, L.: Perceptual losses for real-time style transfer and superresolution. In: European Conference on Computer Vision, vol. 9906, pp. 694–711 (2016) 6. Feng, Z., Yuanjie, S., Yishi, S., et al.: Unsupervised low-light image enhancement via histogram equalization prior. arXiv preprint arXiv:2112.01766 (2021) 7. Wenhui, W., Jian, W., Pingping, Z., et al.: URetinex-Net: retinex-based deep unfolding network for low-light image enhancement. In: Computer Vision and Pattern Recognition, vol. 2022, no. 1, pp. 5891–5900 (2022) 8. Jobson, D.J., Rahman, Z., Woodell, G.A.: Properties and performance of a center/surround retinex. IEEE Trans. Image Process. 6(3), 451–462 (1997) 9. Xiaojie, G., Yu, L., Haibin, L.: LIME: low-light image enhancement via illumination map estimation. IEEE Trans. Image Process. 26(2), 982–993 (2016)

High-Quality Three-Dimensional Reproduction of the Weak Textures on the Surface of Objects Based on Photometric Stereo -Structural Light Yaoshun Yue, Maohai Lin(B) , Kaiwei Zhai, and Wenpeng Sang State Key Laboratory of Biobased Material and Green Papermaking, Faculty of Light Industry, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China [email protected]

Abstract. 3D scanning work and 3D reconstruction systems are key research areas in image vision and 3D printing. However, in its application process, it is difficult to reproduce the texture information and real data of the object surface with high quality and completeness due to the limitations of different scanning methods. To solve the problem of high-quality texture information capture and 3D reproduction of components, the paper proposes a composite measurement method using photometric stereo vision and mechanism light based on multi dynamic data processing. The paper uses structured light technology to measure the overall point cloud data of the workpiece surface, and collaborates with the surface texture information obtained from photometric stereo vision to achieve the fusion of point cloud data and normal phase information. By using the method proposed in this paper, high-precision 3D reconstruction of objects and weak texture optimization have been achieved. Relevant experiments are designed to verify the feasibility and the advantage of the method proposed by the paper. Keywords: 3D reconstruction · Photometric stereo · Structural light · Surface of objects · Collaborative measurement

1 Introduction With the development of machine vision technology, surface three-dimensional measurement technology, also known as 3D reality replication system, has successfully broken the barrier of two-dimensional replication [1], and has been widely used in threedimensional reality modeling, reverse engineering, 3D printing and other high-precision fields [2]. Therefore, it is important to obtain high-quality, high-texture information for 3D scanned model information. In order to improve the reconstruction accuracy and reproduce the three-dimensional information of the real object surface with high-quality, some studies will be based on the fusion of measurement technology with other algorithms or other measurement technology, Müller et al. designed a camera display system based on data iteration to achieve texture information capture of the surface of the object [3]. Ikeda et al. combined photometric stereoscopic, binocular stereo vision and physical data segmentation, using © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 62–68, 2024. https://doi.org/10.1007/978-981-99-9955-2_9

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physical segmentation technology to segment and scan the real object multiple times, and obtain three-dimensional overall information through feature point matching and recombination [4]. Xu et al. combine photometric stereo vision with linear structured light, and use the depth information of structured light to correct the shape deviation of photometric stereo vision [5]. Liang et al. combine photometric stereo vision with deep learning to reduce the training value of the input light source, interpolate training, and calculate the normal vector through the anomaly exclusion of homosexual constraints and global illumination effects [6]. Based on a multi-dynamic data processing method, this paper proposed a composite measurement method using structured light and photometric stereoscopic vision. Through the fusion of point cloud data and phase information, three-dimensional information of object surface can be reproduced with high-quality.

2 Collaborative Measurement Method Based on the three-dimensional surface information measurement of structured light, the 3D information of the object surface can be well expressed, but the expression of the detailed texture cannot reflect the real object texture more realistically [7]. That is, from the two-dimensional wavelet, it can be understood that the low-frequency information of three-dimensional surface information based on structured light has high accuracy, but the high-frequency information cannot express the texture details of the object well. In comparison, the high-frequency information of the photometric stereoscopic measurement results satisfies the real effect. This paper proposes that the data feature point matching of the linear structured light measurement results can be carried out according to the pixel coordinates of the photometric stereo measurement results, and after the pixel point matching is completed, the two-dimensional wavelets are used to filter the two sets of measurement results respectively, filter out the high-frequency information in the line structured light measurement results and the low-frequency information in the photometric stereo measurement results, and select the low-frequency results of linear structured light and the photometric stereo-high frequency results of the appropriate scale, and add the two to obtain fusion results. 2.1 Measurement Method Structure The general flow of the basic scanning scheme and algorithm which was proposed is shown in the flowing Fig. 1. 2.2 Photometric Stereoscopic Acquisition of Normal Vector It is worth noting that for the collection of normal vector information, this article builds a photometric stereo scanning system based on the principle of photometric stereo vision [8]. The structural principle and system a-plane are shown in Fig. 2. The photometric stereo system uses a light matrix and a camera to capture images of different lighting angles, and calculates the normal phase and gradient information

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Fig. 1. Structured light - photometric stereo coordination

of the object surface. If it is assumed that the brightness of a pixel of the object is I0 the unit normal vector of its surface is N0 , the direction of the light source is L0 , ρ is the reflectance of the material surface, according to the Lambert body reflection model: I0 = ρN0 · L0

(1)

Normal vector N is written as a three-dimensional space vector as follows: N = (NX , NY , NZ )T , According to the unknown quantity relationship, in a given m images, the brightness I = (I1 , I2 , I3, · · · Im ), the light source direction L = (L1 , L2 , L3, · · · Lm ), and m ≥ 3 yields an m-dimensional system of linear equations with respect to the unknowns N : ⎧ I1 = ρ(NX · L1X + NY · L1Y + NZ · L1Z ) ⎪ ⎪ ⎪ ⎪ ⎪ I2 = ρ(NX · L2X + NY · L2Y + NZ · L2Z ) ⎪ ⎪ ⎪ ⎪ I ⎨ 3 = ρ(NX · L3X + NY · L3Y + NZ · L3Z ) (2) · ⎪ ⎪ ⎪ · ⎪ ⎪ ⎪ ⎪ · ⎪ ⎪ ⎩ Im = ρ(NX · LmX + NY · LmY + NZ · LmZ ) 

Considering that ρ cannot be guaranteed to be a quantitative quantity, let N = ρN (i, j): 

N = ρN = L−1 I = (LT L)−1 LT I

(3)

Then the surface reflectance: 

ρ = N 

(4)

The single-point pixel normal vector obtained by the least squares method: 

N = N /ρ

(5)

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3 Experimental and Discussion 3.1 Experimental Example The collaborative measurement method does not change the original scanning equipment. In this paper, Reeyee Pro X2 3D structural light scanner [9] and self-built BTF photometric stereo scanning equipment are used. In order to ensure the accuracy of the experiment, the self-error detection and calibration of the instrument have been completed in the preliminary work. According to the scanning method described in Chapter 2, the green throw pillow with fabric texture is taken as the.

Fig. 2. Process of high-quality 3D reproduction of weak texture on the surface of objects

Based on structured light, a group of raster images are projected to the measured object through a 3D laser scanner. At the same time, the CCD camera is used to synchronously shoot the raster images deformed due to the surface fluctuation of the object, carry out phase calculation, and obtain the surface point cloud information. From the scanning effect, it can comprehensively recover the three-dimensional data of the object surface, and the diameter error is small, but the effect on obtaining the texture feature information of the object surface is not very good. Based on photometric stereo technology, a self-built BTF scanning system was used to capture images of real objects under different lighting conditions, achieving texture scanning of real objects and obtaining grayscale gradient maps and normal maps. It can be seen that photometric stereo can effectively represent the surface texture information of objects, but due to the limitations of format, it cannot represent the entire threedimensional data. Based on the respective advantages of structured light and photometric stereo, without changing the original scanning instrument, the three-dimensional point cloud information and texture normal phase information of the pillow are obtained through structured light and photometric stereo, the high-frequency information in the linear structured light measurement results and the low-frequency information in the photometric stereo measurement results are filtered out, and the low-frequency results of the linear structured light and the high-frequency results of the photometric stereo are selected to select

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the appropriate scale, Interpolate to obtain the true surface texture information of the pillow. 3.2 Filter Reconstruction Interpolation In order to express the proposed method more visually, after the complete feature points are matched and the X and Y axes are fixed, the photometric stereo vision and structured light Z axis interval 5 are sampled in the same area, and the two-dimensional plan is displayed, as shown in the Fig. 3 below.

a.

b.

Fig. 3. Comparison of z values of structured light - photometric stereo before processing and after filtering difference fusion

It can be seen from the above figure that the method proposed in this paper combines the advantages of photometric stereo structured light, and high-quality reappears the three-dimensional information of real objects. After data filtering and interpolation fusion of photometric stereo and structured light, the effect obtained not only retains the original large gradient terrain features, but also better displays the weak surface texture information of the image. 3.3 Effect and Evaluation In order to ensure the sufficiency of the experiment, the paper selected 51 real objects with different texture materials. After obtaining the 3D point cloud information of the real object through structured light scanning and the texture normal phase information of the real object through photometric stereo scanning, the measured data is filtered at high and low frequencies through data collaboration, and then the 3D point cloud information is interpolated with the data of normal phase information. The scanning effect obtained is shown in the following Table 1. Observe the experimental effect, based on the collaborative measurement method of photometric stereo and structured light, without changing the original measurement equipment, through the fusion processing of the measurement data, the method proposed in this paper can display the three-dimensional information and texture information of different real objects with high-quality. At the same time, through the measurement of the scanning effect, the scanning error can be stably controlled within 1 mm.

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Table 1. 3D texture scanning effect of real objects

4 Conclusion This paper focuses on the high-quality reproduction of weak textures on real objects. Based on the advantages of photometric stereoscopic scanning and structured light stereoscopic scanning, a collaborative composite measurement method is proposed in this paper. The structural light technology is used to measure the whole electric fish data of the surface of the real object, and at the same time, filter analysis, feature point matching, data interpolation and other work is carried out with the real texture information obtained from the photometric stereo, so as to realize the high-quality three-dimensional reproduction of the weak texture of the real object surface. Through the experimental analysis of real objects, it is proved that this method is feasible and significantly improves the quality of 3D reproduction of real objects. Although this article has preliminarily achieved the integration of weak texture 3D digital scanning and reproduction of real objects, our experimental team also found that this scanning method has shortcomings in the 3D reproduction of complex multi texture real objects under a large amount of scanning data. The author and experimental team are also continuing their efforts to promote high-quality 3D reproduction of real objects.

References 1. Wang, R., Wang, X., He, D., Wang, L., Xu, K.: FCN-based 3D reconstruction with multi-source photometric stereo. Appl. Sci. 10(8), 2914 (2020) 2. Zhang, T., Wu, J., Liu, J.: Learning to estimate surface normal via deep photometric stereo networks. Optik 207, 163802 (2020) 3. Müller, G., Bendels, G.H., Klein, R.: In rapid synchronous acquisition of geometry and appearance of cultural heritage artefacts. VAST 2005, 13–20 (2005)

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4. Ikeda, O.: In Shape reconstruction from two color images using photometric stereo combined with segmentation and stereopsis. In: IEEE Conference on Advanced Video and Signal Based Surveillance, pp 434–438 (2005) 5. Li, X., Fan, H., Qi, L., Chen, Y., Dong, J., Dong, X.: In Combining encoded structured light and photometric stereo for underwater 3D reconstruction. In: 2017 IEEE SmartWorld, Ubiquitous Intelligence & Computing, Advanced & Trusted Computed, Scalable Computing & Communications, Cloud & Big Data Computing, Internet of People and Smart City Innovation (SmartWorld/SCALCOM/UIC/ATC/CBDCom/IOP/SCI), pp 1–6. IEEE (2017) 6. Lu, L., Qi, L., Luo, Y., Jiao, H., Dong, J.: Three-dimensional reconstruction from single image base on combination of CNN and multi-spectral photometric stereo. Sensors 18(3), 764 (2018) 7. Ju, Y., Peng, Y., Jian, M., Gao, F., Dong, J.: Learning conditional photometric stereo with high-resolution features. Comput. Vis. Media 8, 105–118 (2022) 8. Liu, H., Wu, X., Yan, N., Yuan, S., Zhang, X.: A novel image registration-based dynamic photometric stereo method for online defect detection in aluminum alloy castings. Digital Sig. Process. 141, 104165 (2023) 9. Yue, Y., Lin, M.: Analysis and optimization of the point cloud accuracy of the 3D laser scanner based on the surface characteristics of the object. In: Zhao, P., Ye, Z., Xu, M., Yang, L., Zhang, L., Yan, S. (eds.) Interdisciplinary Research for Printing and Packaging. LNEE, vol. 896, pp. 86–92. Springer, Singapore (2022). https://doi.org/10.1007/978-981-19-1673-1_15

Research on High Precision Detection Method of Register Error Based on Machine Vision Han Zhang1 , Shanhui Liu1(B) , Xianju Wang1 , Keliang Wei2 , and Liang Chen3 1 Faculty of Printing, Packaging Engineering and Digital Media Technology, Xi’an University

of Technology, Shaanxi, China [email protected] 2 Shaanxi Beiren Printing Machinery Co., Ltd., Weinan, China 3 Weinan Kesai Machinery and Electronic Equipment Co., Ltd., Weinan, China

Abstract. Register accuracy is an important index to measure the quality of printed electronic products. But the register error detection accuracy of photoelectric sensors cannot meet the requirements of printed electronic register control. For this reason, this paper proposes a sub-pixel-level register error detection method based on machine vision for circular matrix color marks. First, the image preprocessing operation was completed according to the application scene and color mark features. Then, sub-pixel edge extraction was accomplished using the improved Canny operator and Zernike moment method, and high-precision registration error detection was accomplished using least squares fitting. The results show that, compared with the traditional detection methods, this method has better rapidity, accuracy and stability in register error detection. It solves the difficulties of image preprocessing and sub-pixel-level detection under the condition of multi-color groups, and meets the demand for high-precision control of complex printing electronic devices. Keywords: Printed electronics · Register accuracy · Subpixel · Zernike Method

1 Introduction In the manufacturing process of gravure printed electronic devices, register accuracy is an important index to measure the quality of printed electronic products. Due to the electrical performance requirements, printed electronic products require very high register accuracy. Machine vision technology is used to improve the register error detection accuracy of gravure printing equipment to meet the needs of large-scale production of printed electronic products. Many scholars have conducted research based on machine vision. Li [1] and Liu [2] used neural network and interpolation method to detect the traditional printing register error; Li [3], Tsai DM [4] and Hua [5] based on PCB to detect the register error, respectively; Liu [6] proposed a two-edge subpixel model based on spatial moments; Ghosal and Mehrotra [7] proposed for the first time the use of Zernike orthogonal moments to detect subpixel edges; Zhao [8] optimized the radial polynomials of Zernike moments; © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 69–73, 2024. https://doi.org/10.1007/978-981-99-9955-2_10

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Deng and Gwo [9] proposed a method to compute the higher-order generalized Zernike moments; Yang [10] used a Gaussian weighted adaptive thresholding method for Zernike moment. In summary, this paper is structured as follows: Section II introduces the gravure printing structure and color mark principles, and preprocesses the images. Section III extracts pixel-level edges using an improved Canny edge detection operator and subpixel edges using an improved Zernike moments method, and then uses the least squares method to fit the center of the circle of each color mark for registration error detection. Section IV concludes the full paper.

2 Color Marks Image Prepressing As shown in Fig. 1, the material belt in turn through the color group, the color group of color marks will be printed in the established position. The industrial camera installed in the last color group captures images of the complete color mark group. Based on the register detection algorithm calculates the register error, according to the register error control adjustment device for corresponding compensation. Finally achieve the purpose of reducing the register error.

Fig. 1. Gravure printing machine structure principle

A median filter with 3 apertures is selected for denoising the image based on subjective evaluation and objective evaluation method based on MSE and PSNR. Then it is required to localize the colored marker groups in the image. Traversing the center of the circle identified by the Hough gradient method, and locating to the first color marks based on θ and lAB between any two color marks.

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3 High Precision Detection 3.1 Extraction of Pixel-Level Edges In this paper, Canny edge detection algorithm combined with Otsu method is used to achieve pixel-level edge detection without manual threshold adjustment. Sorting method is applied to match to the actual corresponding color group according to the location of circle center. 3.2 Extraction of Sub-Level Edges The ideal step edge model is shown in Fig. 2. The sampling region is a circular region with a certain pixel point O as the center and unit pixel as the radius. The straight line L represents the ideal edge, the two sides of the gray value are h1 and h2 , the step height is k, l is the perpendicular distance from the center of the circle to L, l1 and l 2 are the distances between the center of the circle O and the edges of the image under the condition of the Zernike moments of different orders. Figure 2(b) is rotated clockwise by angle Ø around the origin to obtain Fig. 2(c).

Fig. 2. Zernike moment edge detection model

Let the image f (x, y) = 1 and note that the matrix template of Z nm is M nm , then: ¨ ∗ Mnm = Vnm (ρ, θ )dxdy (1) x2 +y2 ≤1

The 7 × 7 template coefficients for Z 00 , Z 11 , Z 20 , Z 31 , and Z 40 can be calculated from Eq. (1), respectively. Combining the rotational invariance of the Zernike moments and the known conditions derived above, the edge parameters can be derived as follows. ⎧   Im(Z11 ) ⎪ ⎪ φ = arctan ⎪ ⎪ ⎪ Re(Z11 ) ⎪ ⎪ ⎪ ⎪ Z ⎪ 20 ⎪ ⎪ ⎨l = Z  11 (2) 2Z11  ⎪ ⎪ k = ⎪ 3 ⎪ ⎪ 2(1 − l 2 ) 2 ⎪ ⎪ ⎪ √ ⎪ kπ −1 ⎪ 2 ⎪ ⎪ h = Z00 − 2 + k sin (l) + kl 1 − l ⎩ 1 π

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Again, l 1 and l2 are obtained from our derived 3rd and 4th order Zernike moment.  ⎧ ⎪ 5Z40  + 3Z20  ⎪ ⎪ ⎪ ⎨ l1 = 8Z20  (3)  ⎪ ⎪ 5Z  + Z  ⎪ 31 11 ⎪ ⎩ l2 = 6Z11  The sub-pixel edge detection formula can be derived.



xs x0 N cos φ = + l 2 sin φ ys y0

(4)

where (x 0 , y0 ) is the center of the circle and (x s , ys ) are all possible sub-pixel coordinate points, the true sub-pixel level edge points need to be further determined by threshold conditions.

Fig. 3. Single color scale gray image and algorithm implementation effect

As shown in Fig. 3(a) for a single color mark region grayscale histogram, the grayscale step threshold k t is derived when the difference between the mean grayscale values of the foreground color mark and the background is maximum. The difference between the distances l1 and l 2 from the edge of the image to the center of the circle for different orders of Zernike moments conditions is taken as a range of values for l. According to the proposed method, the localization of sub-pixel-level edge coordinates is finally achieved. The local zoomed-in view of a single color mark with different shades of gray is shown in Fig. 3(b). The green dots are the pixel-level edge points extracted using the Canny operator combined with Otsu. The yellow asterisks are the sub-pixel-level edge points extracted using the improved method in this paper. It can be seen that, compared to the pixel-level edge points, sub-pixel-level edge points are smoother, and closer to the real edges at different gray-level steps.

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4 Conclusion Aiming at the problem that the current register detection method cannot meet the requirements of printing electronic register accuracy. This paper proposes a high-precision register error detection method. Firstly, the image preprocessing is completed according to the color marking features. Then, the sub-pixel level edges of the color marks are extracted using a combination of the improved Canny operator and the improved Zernike operator. Finally, the high-precision registration error is calculated. The proposed method greatly improves the accuracy and stability of detection and provides a useful reference for high-precision register error detection. Acknowledgement. This project is supported by the key research and development program of Shaanxi Province (Grant No. 2023-YBGY-329), the scientific research program funded by Shaanxi Provincial education department (Grant No.22JY048) and the key research and development program of Weinan City (Grant No. ZDYFJH-45).

References 1. Li, J., Wu, S., Chang, K., Wang, J.: Research on registration accuracy detection method based on machine vision. J. Phys. Conf. Ser. 2437, 012113 (2023) 2. Liu, K., Fei, M., Zhou, W., Wang, H.: The detection method of printed registration deviations based on machine vision. In: Sun, Z., Deng, Z. (eds.) Proceedings of 2013 Chinese Intelligent Automation Conference. LNEE, vol. 256, pp. 283–290. Springer, Berlin (2013). https://doi. org/10.1007/978-3-642-38466-0_32 3. Li, C., Xu, H., Chen, S.: Design of a precision multi-layer roll-to-roll printing system. Precis. Eng. 66, 564–576 (2020) 4. Tsai, D.M., Hsieh, Y.C.: Machine vision-based positioning and inspection using expectationmaximization technique. IEEE Trans. Instrum. Meas.Instrum. Meas. 66(11), 2858–2868 (2017) 5. Hua, G., Huang, W., Liu, H.: Accurate image registration method for PCB defects detection. J. Eng. 2018(16), 1662–1667 (2018) 6. Liu, W., Zhang, Y., Yu, X.: A novel subpixel industrial chip detection method based on the dual-edge model for surface mount equipment. IEEE Trans. Ind. Inf. 19(1), 232–242 (2023) 7. Ghosal, S., Mehrotra, R.: Orthogonal moment operators for subpixel edge detection. Pattern Recogn.Recogn. 26(2), 295–306 (1993) 8. Zhao, Z., Kuang, X., Zhu, Y., Liang, Y., Xuan, Y.: Combined kernel for fast GPU computation of Zernike moments. Real-Time Image Process. 18(3), 431–444 (2021) 9. Deng, A., Gwo, C.: Efficient computations for generalized Zernike moments and image recovery. Appl. Math. Comput.Comput. 339, 308–322 (2018) 10. Yang, R., Guo, H., Chen, Z., Sun, J.: Adaptive subpixel edge detection for locating the center of nut screw hole. Int. J. Precis. Eng. Manuf. 22, 1357–1364 (2021)

Research on Digital Reproduction Mode of Stone Rubbings Qi Zeng1 , Jinglin Ma2,2(B) , and Qian Shi2 1 Information Engineering Department, Shandong Communication & Media College,

Jinan, China 2 Art Design Department, Shandong Communication & Media College, Jinan, China

[email protected]

Abstract. Stone carving rubbings are an important medium for disseminating history and culture, especially after the national legislation prohibits the production and sale of rubbing, high-quality reproduction of rubbings has become an important form of disseminating stone carving art. In this paper, the digital reproduction mode based on stone engraving rubbings is determined by studying the three aspects of preprocessing before rubbing, digital scanning and image processing, and inkjet printing output with xuan paper as the material. Pre processing before scanning of rubbings mainly study how to remove creases and folds on the basis of protecting the artistic characteristics of rubbing, so as to meet the requirements of scanning and copying. Digital scanning and image processing mainly study the scanning methods and parameter settings for rubbings, and reproduce the unique artistic features of rubbings relative to other paper planar artwork. Inkjet printing output mainly studies the method of printing and copying on two different materials, ordinary xuan paper and coated xuan paper, and makes a comparative analysis with the original rubbings. The research methods of this article are comparative analysis and experimental research, adjust the experimental data according to the results during the experiment, and obtain experimental results that are close to or meet the requirements through trial and error. The conclusion of this paper is that protective reproduction of rubbings can be achieved by formulating appropriate implementation paths. Keywords: Rubbing · Preprocessing · Image processing · Inkjet printing

1 Introduction Stone rubbings are an important medium for spreading history and culture, as well as an important component of traditional Chinese culture. In addition to having cultural heritage significance, rubbings also have various values such as archaeology, historical relic research, and cultural education. Effectively strengthening the protection and utilization of stone rubbings has profound historical and practical significance for inheriting and promoting traditional Chinese culture, and promoting the great development and prosperity of socialist culture [1]. Due to its extreme fragility, stone rubbings need to be protected, especially after national legislation prohibits the production and sale © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 74–78, 2024. https://doi.org/10.1007/978-981-99-9955-2_11

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of rubbings. High quality reproduction of rubbings has become an important form of disseminating stone carving art. The use of computer technology to store stone rubbings in a digital information format, transforming them from non renewable resources to renewable cultural relics, makes the digitization of rubbings particularly important [2]. Transforming the original stone rubbings into electronic files that can be processed by computers through high-precision scanning, using rice paper as the replication material, and using high-precision digital inkjet printing can realistically reproduce all details on the original, including microscopic features such as water marks and mold marks [3]. There has been research on rubbings replication in the academic community, and the digital information collection section of this paper explores the method of using a small scanner to segment scanning and then perform digital stitching. This article determines the digital replication mode based on stone rubbings by studying three aspects: preprocessing before rubbings scanning, digital scanning and image processing, and inkjet printing output using xuan paper as the material.

2 Preprocessing Before Rubbing Scanning During the production process of stone carving rubbings, it is necessary to wet the xuan paper and stick it to the surface of the stone carving. After the paper expands with water, it is pressed to make the xuan paper dent in the lines and text, lower than the height of the stone carving surface. Then, pigment is evenly applied to the surface of the paper, which can replicate the complete content of the stone carving surface, resulting in uneven surface of the rubbings. In addition, during the preservation process of rubbings, folding and squeezing can also form creases and folds on the surface, affecting the scanning and copying effects. Creases are difficult to remove in the image processing process after scanning, which requires preprocessing before scanning to eliminate creases and wrinkles on the surface of the rubbing. In this paper, water mist is used to wet the back of the rubbing to soften and deform the paper fibers, and then the moistened rubbing is heated and pressurized to eliminate wrinkles. 2.1 Materials Yongchun brand 3DZBJ mounting machine; Sprinkler; Purified water; Stone Rubbings. 2.2 Experimentation Use a spray can to evenly spray pure water in the form of water mist on the back of the rubbings, soften and deform the rice paper, and then put it into the mounting machine. Set the heating temperature to 80°C, the pressure to 400N, and the pressure time to 30s to obtain the stone rubbings that remove wrinkles. The experimental parameters of this paper draw on the parameters used in the traditional calligraphy and painting mounting industry. Experiments have shown that after wetting the rubbing with water mist, most of the wrinkles can be removed by heating and pressing, leaving only slight creases, achieving good experimental results as shown in Fig. 1. Residual creases can be repaired during later image processing.

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a. Rubbings original b. Rubbings with wrinkles removed Fig. 1. Comparison of rubbings preprocessing

3 Digital Scanning of Rubbings Digital scanning is the process of fragmented surface information on rubbings, converting continuous manuscripts into discrete digital pixels. The density of pixel acquisition determines the clarity of digital images. This paper sets the digital scanning accuracy to 400ppi based on the set print output resolution requirements. The scanning equipment used is the Zhongjing 9900XL scanner, with a maximum scanning width of 30.5 × 43 cm, the original format of the rubbing is 68 × 68 cm. Use a scanner to scan the original rubbings into multiple fragments, and use Photoshop’s plugin Photomerge to merge multiple fragments into a complete image as shown in Fig. 2.

Fig. 2. Scanned rubbing fragments and the entire image after merging

The quality of images automatically assembled using computers and software is better than that of manually assembled images, and there is no phenomenon of pixel loss or repetition.

4 Image Processing and Inkjet Printing of Rubbings The image processing process of rubbings requires repairing minor creases remaining, and repairing any defects on the original as needed. Sometimes, according to the requirement of preserving the original appearance, some obvious defects cannot be repaired

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and must be preserved on the replica. On the other hand, it is necessary to adjust the color curve of the image to ensure that the overall color of the inkjet printed copy is as consistent as possible with the original. Coated xuan paper can fix ink on the surface of xuan paper, to some extent avoiding ink infiltration into the interior of the paper, and improving the color reproduction of xuan paper. This paper uses coated xuan paper and pigment ink for image processing and inkjet printing experiments of rubbings. The equipment and materials used in the experiment are shown in Table1. Table 1. Equipment and Materials Experimental equipment Model printer

Epson 9880

ink

K3 pigment ink

paper

65g/M2 coated xuan paper

Because the overall color scheme of the rubbings is different levels of gray, setting the black generation method for converting the rubbings image from RGB mode to CMYK mode to ’Heavy’ can obtain a black channel with more information as shown in Fig. 3, making it easy to adjust the overall color scheme of the rubbings.

Fig. 3. Set the black channel generation method to ’Heavy’

After converting to CMYK mode, the ink jet printing effect of the rubbing image is continuously adjusted by adjusting the ’Curves’ of the image. In this paper, color adjustment is achieved by overlaying the ’Adjustment Layer’ as shown in Fig. 4. After stacking three ’Adjustment Layers’, use 720 × 720dpi output resolution, resulting in a replica that matches the color of the original rubbing element as shown in Fig. 5. The selection of parameters in this experiment is based on the trial and error process, and the parameter values are adjusted continuously to obtain satisfactory results.

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Fig. 4. Overlaying the ’Adjustment Layer’

Fig. 5. Comparison of rubbings reproduction effects

5 Conclusion This article removes creases and wrinkles on the surface of rubbings through preprocessing before scanning, so that the rubbings meet the scanning conditions. Using a segmented scanning method, the overall image of the rubbings is pieced together. Image processing is used to repair minor creases in the rubbings, convert them into a CMYK mode image with more black information, set multiple ’Adjustment Layers’ to adjust the color of the image, use an inkjet printer to obtain a replica that matches the original color of the rubbings, and finally determine the digital replication mode based on stone rubbings. In the absence of a large scanner, this paper has reference value for using a small scanner for rubbing replication.

References 1. Ma, C.: On the protection and utilization of stone rubbings. Confucius Temple Guozijian Treatise Series 00, 92–99 (2020) 2. Ji, J., Fang, S., Gong, Y.: Research on digital protection of stone rubbings. Huaxia Archaeol. 03, 116–122 (2020) 3. Wang, H.: The wonderful application of digital spray painting technology in the reproduction of temple stele rubbings. Screen Print 01, 32–37 (2014)

Printing Engineering Technology

Study of the Effect of Piezoelectric Inkjet Drive Waveform Parameters on Droplet Injection Characteristics Qiumin Wu(B) , Sa Li, Yili Ma, and Chaoyue Lin Faculty of Printing, Packing Engineering and Digital Media Technology, Xi’an University of Technology, Shaanxi, China [email protected]

Abstract. Piezoelectric inkjet printing technology is widely used in the fields of microinjection, printed electronics and biotechnology due to its high precision, stability and adaptability. The drive waveform of piezoelectric inkjet has a significant impact on the velocity and volume of the droplets injected and whether satellite droplets are formed.In this paper, the finite element numerical simulation software Comsol is used to establish the simulation model of piezoelectric actuator and printhead.The most widely used positive trapezoidal waveform in piezoelectric inkjet is selected as an object to investigate the effect of drive waveform parameters on the droplet injection characteristics. The main parameters are the voltage rise time t rise , the voltage dwell time t dwell and the voltage fall time t fall .The results show that the voltage rise time t rise mainly affects the first negative pressure generated inside the chamber, the voltage dwell time t dwell and voltage fall time t fall have a great influence on the droplet injection velocity, and the droplet velocity increases first and then decreases with the increase of voltage dwell time t dwell and voltage fall time t fall . Keywords: Piezoelectric inkjet · Droplet jet characteristics · Drive waveform

1

Introduction

The working principle of piezoelectric inkjet technology is shown in Fig. 1. Piezoelectric inkjet technology relies on drive waveform to drive the piezoelectric element to deform it, causing a change in the volume of the ink chamber to generate and eject droplet. The drive waveform of piezoelectric inkjet has an important influence on the droplet injection characteristics [1]. In this paper, unipolar trapezoidal wave, which is widely used in piezoelectric inkjet, is taken as an example to explore the influence of driving waveform parameters on the droplet injection characteristics.

© The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 81–87, 2024. https://doi.org/10.1007/978-981-99-9955-2_12

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Channel Wall

Murky accent

Spray hole

Fig 1. Working principle of piezoelectric inkjet printing technology

2

Establishment of Finite Element Model

A model of the piezoelectric inkjet printhead was created by the software COMSOL as shown in Fig. 2. It consists of a piezoelectric actuator, an ink supply chamber, a flow limiting section, a pressure chamber and a nozzle. The piezoelectric actuator mainly consists of Lead Zirconium Titanate (PZT) piezoelectric film and SiO2 vibrating plate, etc. The voltage drive signal is added directly to the upper surface of the PZT piezoelectric film and the lower surface is grounded. The geometric parameters of the piezoelectric inkjet printhead simulation model are shown in Table 1. width

Piezoelectric actuator

gth

len

PZT Film SiO2Vibrating plates Height

Restrictor

Ink supply channel

Nozzle Pressure chamber

Fig. 2. Piezoelectric inkjet printhead structure simulation diagram

Table 1. Geometric parameters of the piezoelectric inkjet printhead Name

Size(µm)

The length, width and thickness of SiO2 vibrating plate

800, 120, 0.9

The length, width and thickness of PZT piezoelectric film The length, width and thickness of ink supply chamber The length, width and thickness of flow limiting section Diameter of large circle, diameter of small circle, height of nozzle

800, 100, 1 800, 120, 100 800, 40, 100 50, 30, 45

In the selection of materials, Lead Zirconate Titanate-5H, a piezoelectric material with a Young’s modulus of 56 GPa, Poisson’s ratio of 0.36 and a density of 7450 kg/m3 ,

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was chosen as the piezoelectric film. The Young’s modulus of SiO2 vibrating plate is 72 GPa, Poisson’s ratio is 0.17, and the density is 2200 kg/m3 . The nozzle outlet and the ink supply chamber inlet are in direct communication with the outside world, so they are set as open boundaries. The interface between the piezoelectric actuator and the pressure chamber is the fluid-solid coupling surface, so it is possible to transfer data between the two physical fields and use “a moving mesh method” method to deal with the variation of the solid-liquid coupling surface.

3 Effect of Drive Waveform Parameters on Droplet Injection Taking positive polarity single trapezoidal waveform as an example, the influence of driving waveform parameters on droplet injection was studied. As shown in Fig. 3, the parameters include voltage rise time t rise , voltage dwell time t dwell and voltage fall time t fall , where voltage dwell time t dwell is the key parameter affecting droplet injection [2]. Voltage (V)

Time ( s)

Fig. 3. Positive polarity single trapezoidal drive waveform

3.1 Effect of Voltage Rise Time t rise on Droplet Injection During the voltage rise phase, the piezoelectric actuator bends upward making the volume of the chamber larger, and a negative pressure is generated inside the chamber and propagates to both ends. The ink at both ends is sucked back into the chamber and forms a depressed liquid surface at the nozzle [3], the process is shown in Fig. 4. In this period, it needs to provide sufficient ink for droplet injection, and to avoid over-absorption of ink at the nozzle, the pressure at the nozzle should not be too high [4]. To study the effect of rise time t rise on droplet injection individually, the piezoelectric inkjet printhead is loaded with the drive waveform shown in Fig. 5, which consists of two parts: voltage rise time t rise and voltage dwell time t dwell . As shown in Fig. 6, fluid velocity at the orifice decreases with increasing t rise at the nozzle.As shown in Fig. 7, when t rise increases, the change of pressure wave at the nozzle is basically similar, the main difference is the pressure value of the first negative pressure. As t rise gradually increases, the first negative pressure gradually decreases. The reason for this phenomenon is that as the t rise value increases, the rate of voltage rise

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Bent liquid level

Fig. 4. Droplet injection diagram

Fig. 5. Drive waveform used to optimize t rise

decreases and the deformation of the piezoelectric actuator becomes slower, resulting in the pressure of the fluid at the nozzle decreasingly. In the inkjet printing process, the first negative pressure directly affects the volume of liquid absorbed and also determines the initial droplet volume.

Fig. 6. Peak velocity curve at the nozzle

Fig. 7. Pressure-time curve at the nozzle hole

3.2 Effect of Voltage Fall Time t fall on Droplet Injection During the voltage fall phase, the piezoelectric actuator returns to its initial position and the chamber contracts, generating a positive pressure. This pressure wave is superimposed with the pressure wave reflected from the voltage rise phase, with the result that the positive pressure wave strengthens and the negative pressure wave disappears. The superimposed positive pressure wave propagates to the nozzle and the ink is extruded from the nozzle under pressure [5]. The droplet are ejected in the state shown in Fig. 8. The piezoelectric inkjet printhead is loaded with the drive waveform shown in Fig. 9.

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Push

Ink jet

Fig. 8. Droplet injection diagram

Fig. 9. Drive waveform used to optimize tfall

Velocity (m/s)

Therefore, when the voltage fall time is optimized, the goal is greater pressure at the nozzle and faster fluid velocity. The higher pressure at the nozzle not only makes ink easier to be ejected from the nozzle, but also helps to enhance the stability of the droplet tail column and reduces the chance of satellite droplets occurring. It can be seen from Fig. 10, with the increase of voltage fall time t fall , the fluid velocity at the nozzle increases firstly and then decreases. As is shown in Fig. 11, the trend of the pressure wave at the nozzle with the voltage fall time t fall is similar, mainly because of the difference in the pressure value of the first positive pressure.

Voltage drop time ( s)

Fig. 10. Peak velocity curve at the nozzle

Fig. 11. Pressure variation curve at the nozzle

3.3 Effect of Voltage Dwell Time t dwell on Droplet Injection During the voltage dwell phase, the negative pressure wave generated during the voltage rise propagates and reflects within the chamber. Later the negative pressure is superimposed or under-canceled with the positive pressure wave generated during the voltage fall. The value of the voltage dwell time determines the mutual superposition or canceling effect of the pressure waves on each other. The ideal result is that the positive pressure wave generated during the voltage fall phase and the positive pressure wave reflected during the voltage rise phase are superimposed on each other and doubled, and the negative pressure wave reflected by them cancel each other to zero. Therefore, when the positive pressure wave, which is doubled by superposition, reaches the nozzle, the fluid in the nozzle can be ejected at a faster rate. Apply the drive waveform to the piezoelectric inkjet printhead as shown in Fig. 12, set the voltage rise time to 3µs and the voltage fall time to 3µs, and only change the

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Velocity (m/s)

voltage dwell time to analyze the effect of voltage dwell time on droplet formation. As is shown in Fig. 13, with the increase of voltage dwell time, the droplet velocity first increases and then decreases. This is because when the voltage dwell time t dwell is too large or too small, the pressure waves generated by the rising and falling voltage phases cancel each other, making the final pressure at the nozzle reduced, which in turn causes a slowdown in fluid movement at the nozzle.

Voltage dwell time ( s)

Fig. 12. Drive waveform

Fig. 13. Peak velocity curve at the nozzle

4 Conclusion The drive waveform applied on the piezoelectric inkjet printhead has a significant impact on the droplet injection. In this paper, a positive polarity single trapezoidal waveform is chosen, and the effect of the drive waveform parameters on the droplet injection characteristics is investigated using a numerical simulation model. In general, the voltage rise time t rise value mainly affects the first negative pressure value, a reasonable setting of the t rise value avoid ink over-absorption at the nozzle. The proper voltage dwell time t dwell value amplify or eliminate the maximum positive pressure value. When the t dwell value is optimal, the droplet velocity is maximum. The voltage fall time t fall mainly affects the first positive voltage, and a reasonably set value of the voltage fall time t fall allows the droplet to obtain a higher injection speed. Acknowledgments. This research is supported by the Shaanxi Provincial Natural Science Basic Research Program Key Project (No. 2022JZ-30) and the Shaanxi Provincial Department of Education Key Scientific Research Program (No. 20JY054).

References 1. Liu, N., Sheng, X., Zhang, M., et al. Squeeze-Type piezoelectric inkjet printhead actuating waveform design method Based Numer. Simul. Exp. Micromachines 13(10), 1695(2022) 2. Szczech, J.B., Megaridis, C.M., Gamota, D.R., et al.: Fine-line conductor manufacturing using drop-on demand PZT printing technology. IEEE Trans. Electron. Packag. Manuf. Packag. Manuf. 25(1), 26–33 (2002) 3. Kwon, K.S., Kim, W.: A waveform design method for high-speed inkjet printing based on self-sensing measurement. Sens. Actuators, A 140(1), 75–83 (2007)

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4. Liu, Y.F., Pai, Y.F., Tsai, M.H., et al.: Investigation of driving waveform and resonance pressure in piezoelectric inkjet printing. Appl. Phys. A 109(2), 323–329 (2012) 5. Xiao, X., Xing, W., Da, C., et al.: A waveform design method for piezoelectric inkjet printhead with Doppler vibration test and numerical simulation. Microelectron. Eng. Eng. 196, 13–19 (2018)

Numerical Investigation of the Spreading Behavior of Inkjet Droplets on Rough Substrate Surface Qiumin Wu(B) , Yili Ma, Sa Li, and Xinyu Cui Faculty of Printing, Packing Engineering and Digital Media Technology, Xi’an University of Technology, Shaanxi, China [email protected]

Abstract. Inkjet printing is a non-contact printing technology, which has the advantages of wide substrates, environmental protection, and can meet the requirements of personalized printing. After the ink droplets are ejected from the nozzle, they fly to the surface of the printing material. The spreading results will directly affect the printing quality of inkjet printing. This present work uses ANSYS software and introduces a standard k − ε turbulence model to create a numerical calculation model of droplet spreading on rough substrate surface. The effects and relationships between droplet diameter, flight speed, fluid viscosity and droplet spreading coefficient, maximum spreading diameter and stable spreading time on the surface of rough substrates were investigated and obtained. The results provide theoretical basis for improving the quality of inkjet printing. Keywords: Inkjet printing · Numerical simulation · Droplet spreading

1 Introduction Inkjet printing is the most widely used technology in digital printing, and it is a noncontact printing technology. The principle of inkjet printing is to convert the image and text information into pulse electrical signals and transmit them to the inkjet equipment through the control of the computer. The inkjet control system calculates the amount of ink used in the corresponding channel and controls the ink jet to the surface of the substrate and deposited in the designated area, thus reproducing the graphic information on the surface of the substrate. Islamova A G and other scholars [1] have studied the impact of water droplets with different physical properties on surfaces with different wettability. Guan C [2] simulated the wetting of aluminum droplets impacting a rough surface composed of various materials. MAbolghasamibizaki [3] conducted experiments on different volumes of liquid droplets and the size of textured surfaces, and studied the impact dynamics of liquid droplets on textured surfaces at different impact velocities. Ilia V. Roisman [4] established a splash threshold model, analyzed the impact of droplet spread on rough and porous substrates. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 88–94, 2024. https://doi.org/10.1007/978-981-99-9955-2_13

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In order to have a clearer understanding of the motion of inkjet droplets on rough wall surfaces, we numerically investigated the spreading characteristics of droplets on substrate surfaces of different roughness in terms of the state of the droplets after injection (droplet diameter and flight velocity) and the properties of the ink itself (droplet viscosity). The effects and relationships between droplet diameter, flight speed, and fluid viscosity on droplet spreading coefficient, maximum spreading diameter, and stable diffusion time on rough substrate surfaces are obtained.

2 Mathematical Model 2.1 Model Analysis ANSYS GEOMETRY is used for geometric modeling, and the computational physical model is simplified to a two-dimensional plane. Using square grids for grid partitioning in ICEM. Its interior is air medium, its side and upper boundary are pressure inlets, and its bottom side is the rough wall. The physical model of the spreading behavior of inkjet droplets on the rough substrate surface is shown in Fig. 1.

Fig. 1. Physical model of droplet impacting the wall

2.2 Rough Surface Selection and Turbulence Model In inkjet printing, different types of substrates have different roughness. With reference to the paper roughness measured in the experiment, select the average value: the newspaper roughness is Ra = 4.06 µ m, the inkjet printing paper is Ra = 1.7625 µ m, and the roughness of art-coated paper is Ra = 0.95 µ m. Energy changes such as heat transfer are not considered in this paper. The coefficients of the standard K − ε turbulence model are obtained from simple turbulent flow experiments and the model gives the best convergence results for this study. Therefore, the standard K − ε turbulence model is introduced for the simulation of droplets impacting the rough substrate surfaces.

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2.3 Two-Phase Flow Interface Processing Method and PISO Algorithm The volume tracking method VOF (Volume of fluid) based on Euler system is used to track the two-phase interface. In the VOF model, the specified function C is introduced. Through the value C in the control unit and its connecting unit, the droplet interface can be obtained by the piecewise linear interface calculation method, thus determine the shape and size of the droplet. In this paper, energy changes such as heat transfer are not considered. For transient problems, PISO algorithm has obvious advantages over SIMPLE algorithm, and its computational efficiency and convergence speed have many advantages. Therefore, aiming at the transient problem of liquid droplet impacting on rough surface, the PISO algorithm was adopted in pressure velocity coupling.

3 Result and Discussion 3.1 Effect of Droplet Diameter on Spreading Characteristics In inkjet printing, the range of droplet volume values is 5pl-400pl (micro liters, 1pl = 10−12 l) [5]. Figure 2 shows the spreading patterns of droplets of 0.08mm and 0.09mm diameter impacting smooth substrates, newsprint with a roughness of Ra = 4.06µm, inkjet printing paper with a roughness of Ra = 1.7625µm and art-coated paper with a roughness of Ra = 0.95µm respectively.

Fig. 2. Spreading pattern of liquid droplets on smooth substrate, art-coated paper, inkjet printing paper, and newsprint (a) D0 = 0.08mm (b) D0 = 0.09mm

The specific simulation parameters are shown in Table 1 and Table 2. When droplets of the same diameter impact the surface of substrates with different roughness, the spreading diameter decreases as the roughness increases, the retraction increases, the spreading coefficient decreases and the spreading time required to reach stability is reduced. When droplets of different diameters impact the surface of a substrate with the same roughness, the spreading diameter increases as the droplet diameter increases, the spreading coefficient decreases and the spreading time is reduced. When liquid droplets are spread on the surface of paper with high roughness, they exhibit characteristics of being difficult to spread and retract.

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Table 1. Simulation result data(D0 = 0.08mm) No

substrate

Roughness/µm

Spread diameter/mm

Spread coefficient

Spread time/µs

1

Smooth solid

\

0.2

2.5

1336

2

art-coated paper 0.95

0.149

1.8625

421

3

inkjet printing paper

1.7625

0.146

1.825

418

4

newspaper

4.06

0.142

1.775

404

Table 2. Simulation result data(D0 = 0.09mm) No

substrate

Roughness/µm

Spread diameter/mm

Spread coefficient

Spread time/µs

1

Smooth solid

\

0.171

1.9

746

2

art-coated paper 0.95

0.151

1.678

306

3

inkjet printing paper

1.7625

0.148

1.644

318

4

newspaper

4.06

0.146

1.622

324

3.2 Effect of Flight Speed on Spreading Characteristics Take two sets of data with droplet flying speeds of 4 m/s and 6 m/s, and there are significant differences in the results. As shown in Fig. 3, when the droplet diameter is 0.08 mm and the flight speed is 4 m/s, the droplet impacting the rough substrate surface presents a retraction spread. The spreading time decreases with the increase of roughness, and the maximum spreading diameter decreases with the increase of roughness. When the droplet flying speed is 6 m/s, the droplet impacts the rough substrate surface and produces a retraction and spreading phenomenon. The spreading time at the stable moment decreases as the roughness of the substrate increases, and the maximum spreading diameter of the liquid droplet is equal to the spreading diameter at the stable moment. As shown in Fig. 4, with the increase in substrate roughness, the spread diameter and spread coefficient of liquid droplets impacting the substrate decrease. The research results show that the spreading diameter of the droplet on the rough substrate surface increases with the increase of the droplet flying speed. The spreading diameter obtained when the droplet flying speed is 6 m/s is approximately equal to twice the spreading diameter obtained when the droplet flying speed is 4 m/s. It can be seen that the droplet flying speed has an important impact on the spreading characteristics such as the spreading shape and diameter of the droplet impacting the rough substrate surface.

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Fig. 3. Spreading pattern of liquid droplets on smooth substrate, art-coated paper, inkjet printing paper, and newsprint (a) V = 4 m/s D0 = 0.08mm (b) V = 6 m/s D0 = 0.08mm

Fig. 4. Different flight speeds: (a) Curve of roughness and spreading diameter (b) Curve of roughness and spreading coefficien

3.3 Effect of Fluid Viscosity on Spreading Characteristics The viscosity range of inkjet ink selected by the simulation is 3.5Pa·s and 5Pa·s, which can achieve good spraying effect in inkjet printing. The impact of the viscosity range on the spreading characteristics of droplets impacting paper with different roughness is analyzed. As shown in Fig. 5 and Fig. 6, when the droplet diameter is 0.08 mm and the fluid viscosity is 3.5 Pa·s, the spreading pattern of impacting the surface of paper with different roughness exhibits stable diffusion spreading. The spreading time decreases with the increase of roughness, and the maximum spreading diameter is equal to the spreading diameter at stable time. When the droplet diameter is 0.09mm and the viscosity is µ = 3.5 Pa·s, significant retraction and spreading phenomena occur on the surface of the rough substrate when the droplet strikes.

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Fig. 5. Spreading pattern of liquid droplets on smooth substrate, art-coated paper, inkjet printing paper, and newsprint (a) D0 = 0.08mm, µ = 3.5 Pa·s (b) D0 = 0.08mm, µ = 5 Pa·s

Fig. 6. Different fluid viscosity: (a) Curve of roughness and spreading diameter (b) Curve of roughness and spreading coefficient different fluid viscosity

4 Conclusions This article investigates the motion of inkjet droplets on a rough substrate surface. The dynamic changes in the unfolding shape and unfolding time of droplets with different roughness impacting paper were analyzed. The relationship between droplet diameter, flight speed, fluid viscosity, and droplet diffusion coefficient, maximum diffusion diameter, and stable diffusion time on a rough substrate surface was studied. The research results indicate that as the droplet diameter increases, the spreading diameter increases, the spreading coefficient decreases, and the spreading time shortens. As the flying speed of droplets increases, the spreading diameter of droplets on the rough substrate surface increases. The higher the viscosity, the smaller the spreading coefficient and spreading diameter. Acknowledgments. This research is supported by the Shaanxi Provincial Natural Science Basic Research Program Key Project (No. 2022JZ-30) and the Shaanxi Provincial Department of Education Key Scientific Research Program (No. 20JY054).

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References 1. Islamova, A.G., Kerimbekova, S.A., Shlegel, N.E.E., et al.: Droplet-droplet, droplet-particle, and droplet-substrate collision behavior[J]. Powder Technol. 403, 117371 (2022) 2. Guan, C., Lv, X., Han, Z., Chen, C.: The wetting characteristics of aluminum droplets on rough surfaces with molecular dynamics simulations. Phys Chem. Chem. Phys, Jan 28;22(4):2361– 2371(2020) 3. Abolghasemibizaki, M., Mohammadi, R.: Droplet impact on superhydrophobic surfaces fully decorated with cylindrical macrotextures[J]. J. Colloid Interface Sci. 509, 422–431 (2018) 4. Roisman, I.V., Lembach, A., Tropea, C.: Drop splashing induced by target roughness and porosity: The size plays no role[J]. Adv. Coll. Interface. Sci. 222, 615–621 (2015) 5. Li, H., Liu, J., Li, K., et al. Piezoelectric Micro-Jet devices: a review [J]. Sens. Actuators A: Physical, 297(2019)

Research on Digital Inkjet Printability Based on Garment Fabrics Sitong Liu, Jinglin Ma(B) , and Yiyu Zhang Art Design Department, Shandong Communication & Media College, Jinan, China [email protected]

Abstract. Digital inkjet printing is an important form of personalized design for clothing fabric printing. Compared to screen printing, it has the characteristics of fast speed, high efficiency, wide color gamut, and can achieve large format pattern output. Ordinary textile fabrics are prone to ink droplet diffusion and low color restoration during inkjet printing. This article uses experimental research methods to study methods for improving the suitability of textile fabrics for inkjet printing through prepress pretreatment. This article uses fiber blended fabrics as inkjet printing substrates, uses modifiers and water repellent treatment agents to pre-treat the fabrics, and uses pigment ink for printing. The differences in ink droplet spread shape, K/S value, color recovery, and other aspects between ordinary fabrics and fabrics pretreated with different concentrations of treatment agents are compared, and the impact of prepress pretreatment on improving the inkjet printing suitability of clothing fabrics is analyzed. The conclusion of this article is that pre-treatment of fiber textile fabrics with modifiers and water repellent agents can effectively improve their inkjet printing suitability. Keywords: Digital inkjet printing · prepress preprocessing · K/S value

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Introduction

Against the backdrop of low-carbon environmental protection, personalized design, and customization, compared to traditional screen printing, digital printing technology is in a rising and rapid development stage due to its many advantages such as simple process, short production cycle, low sewage discharge, and unrestricted pattern design [1]. In some application fields, it is gradually replacing traditional printing and dyeing [2]. Ink jet printing is the main implementation form of digital printing technology, and ink is the most important consumable for ink jet printing. It is divided into dye ink and pigment ink according to the type of color agent. Compared to dye ink, pigment ink has more advantages. Pigment ink can be applied to various types of fiber fabrics, especially in the printing and dyeing process of fabrics mixed with various fibers, which has obvious advantages. In addition, pigment ink has better color rendering and firmness than dye ink. In the process of inkjet printing based on fiber fabrics, if pre press pretreatment process is not used, the infiltration phenomenon caused by capillary wicking of ink droplets on the fabric is very serious, which will greatly reduce the accuracy of pattern © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 95–101, 2024. https://doi.org/10.1007/978-981-99-9955-2_14

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printing and reduce printing quality. Therefore, under the requirements of color rendering performance, it is particularly important to suppress ink droplet infiltration [3]. This paper conducts experimental research on a multi fiber blended fabric as the substrate. The fabric is pretreated with different concentrations of ammonium chloride cationic modifiers and fluorine containing water repellents, and printed with pigment ink. The differences in ink droplet spread shape, K/S value, color reduction degree, and other aspects between the untreated fabric and the fabric pretreated with different concentrations of treatment agents are compared, Analyze the impact of prepress on improving the inkjet printing suitability of clothing fabrics. The function of cationic modifiers is to change the surface chemical properties of the fabric to positive, slowing down the penetration of ink droplets caused by electrostatic repulsion between the fabric and pigment particles, improving the adhesion of the fiber surface to ink, and reducing the surface tension of the fabric, making it difficult for ink droplets to diffuse on the fiber surface. The area of ink droplets formed is smaller than the area of untreated fabric, which hinders the diffusion and infiltration of pigment ink droplets to a certain extent, Improving the clarity of the pattern outline after printing is beneficial for improving the final color rendering effect [4]. Water repellents can make fabrics waterproof and stain resistant, reduce the wetting performance of the fabric, and have a certain aggregation effect on the behavior and morphology of pigment droplets, thereby reducing the excessive diffusion and infiltration of ink along the warp and weft directions in porous fabrics, and improving the clarity of the printed pattern. Cationic modifiers not only improve the clarity and color rendering of inkjet printing on fabrics, but also affect their hand feel and wearing comfort. The use of water repellents can improve the fabric’s waterproof and stain repellent function, inhibit ink droplet diffusion, and improve its softness and comfort. This paper uses cationic modifiers with concentrations of 0.5%, 1%, 1.5%, 2%, and 2.5%, as well as fluorinated water repellents with concentrations of 0.05%, 0.1%, 0.15%, and 0.2%, to pretreat a fabric and compare and analyze the performance characteristics of pigment inks on different pretreated fabrics.The component of the cationic modifier is ammonium chloride,and the component of the water repellent is fluorocarbon acrylic resin.

2 Effect of Fabric Surface Modification on the Spreading Form of Ink Drops 2.1 Spreading Morphology of Ink Droplets on Fabrics Treated with Different Concentrations of Cationic Modifiers Using 5µl Pigment Ink The experiment shows that when the concentration of cationic modifier is 1%, the ink droplet spreading form has the minimum spreading area, edge infiltration is suppressed to the maximum extent, and has a high color gain as shown in Fig. 1.This experiment used a quantitative pipette for micro testing and an electronic magnifying glass for observation.

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Fig.1. Spreading morphology of pigment ink droplets on fabrics treated with different concentrations of cationic modifiers

2.2 Spreading Morphology of Ink Droplets on Fabrics Treated with Different Concentrations of Water Repellents Using 5µl Pigment Ink Experiments have shown that at a water repellent concentration of 0.05%, ink droplets are most concentrated and have the smallest spreading area, resulting in the darkest inner ring in the middle of the color block as shown in Fig. 2.

Fig.2. Spreading morphology of pigment ink droplets on fabrics treated with different concentrations of water repellents

2.3 Spreading Morphology of Ink Droplets on Fabrics Treated with Mixed Pre-treatment Agents Using 5µl Pigment Ink Experiments have shown that after pre-treatment with a mixture of modifier and water repellent concentrations of 1% and 0.05%, the morphology of pigment ink on the surface of the fabric is more aggregated, the ink droplet area is smaller, and the edges are clearer. This indicates that both treatment agents have produced a synergistic effect and further improved the experimental results of ink droplets as shown in Fig. 3.

Fig.3. Spreading morphology of ink droplets on fabrics treated with a mixture of 1% modifier and 0.05% water repellent for pigment ink

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Effect of Fabric Surface Modification on the Color Depth

The K/S value of the fabric surface is an important data to measure the depth of color gain of the fabric. This experiment uses a spectrophotometer to measure and calculate the K/S value in the middle of the ink drops on the pretreated fabric surface. The larger the K/S value, the deeper the color of the Test point on the fabric surface, and the better the dyeing performance. 3.1 K/S Value of Ink Droplets on Fabrics Treated with Different Concentrations of Cationic Modifiers K/S = (1-R)2 /2R, K is the absorption coefficient, S is the scattering coefficient, R is the reflectivity at the maximum absorption wavelength when light is not transmitted, the calculation process is no longer stated in this paper. The experiment shows that after the ink droplets are fully spread out, the K/S value on the front side shows an upward trend. When the concentration is 1%, the K/S value is the highest and the color rendering is the best. When the concentration continues to increase, the K/S value slightly decreases as shown in Table 1 and Fig. 4. Table 1. K/S value of ink droplets on fabrics treated with different concentrations of cationic modifiers Modifier concentration

0%

0.5%

1%

1.5%

2%

2.5%

Ink drop K/S value

1.7964

2.6973

3.1362

3.1065

3.1007

3.0352

Fig.4. K/S value of ink droplets on fabrics treated with different concentrations of cationic modifiers

3.2 K/S Value of Ink Droplets on Fabrics Treated with Different Concentrations of Water Repellents The experiment shows that after the ink droplets are fully spread, the positive K/S value shows a trend of first increasing and then decreasing, with the K/S value reaching its maximum at a concentration of 0.05% as shown in Table 2 and Fig. 5.

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Table 2. K/S value of ink droplets on fabrics treated with different concentrations of water repellents Water repellent concentration

0%

0.05%

0.1%

0.15%

0.2%

Ink drop K/S value

1.9386

2.1396

2.0483

1.8573

1.7962

Fig.5. K/S value of ink droplets on fabrics treated with different concentrations of water repellents

3.3 Comparison of K/S values of Ink Droplets on Fabrics Treated with Three Treatment Agents The experiment shows that after the ink droplets are fully spread out, the fabric treated with a mixed treatment agent has the best color rendering performance as shown in Table 3 and Fig. 6. Table 3. K/S value of ink droplets on fabrics treated with different treatment agents Treatment agent

1% cationic modifier

0.05% water repellent

Mixed treatment agent

Ink drop K/S value

3.1362

2.1396

3.8759

Fig.6. K/S value of ink droplets on fabrics treated with three different treatment agents

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4 Effect of Fabric Surface Modification on Inkjet Printing Using Epson 9880 inkjet printer, K3 pigment ink, 720ppi printing resolution, color patterns were printed on untreated fabrics, fabrics treated with 1% cationic modifier, and fabrics treated with mixed treatment agent, and different effect test samples were obtained as shown in Fig. 7.

a. Original manuscript; b. No pre-treatment; c. 1% cationic modifier treatment; d. Mixed treatment agent treatment Fig.7. Effect of fabric surface modification on inkjet printing

The experimental results show that the color depth and saturation of the patterns printed on the untreated sample fabric are very low, the overall color rendering is dim, the edges are blurry, and the printing effect is poor. The fabric treated with 1% cationic modifier has a significant improvement in color rendering depth, while the contour is clearer and the phenomenon of fine line edge infiltration is greatly suppressed. Compared with the original manuscript, it has better color performance and pattern printing accuracy. For fabrics treated with mixed treatment agents, the clarity of the pattern edges is further improved, and the color rendering effect is more vivid in depth. The overall pattern also presents better three-dimensional and color transition effects, and the overall printing effect is significantly improved.

5 Conclusion This paper uses cellulose based blended fabrics as the substrate, selects cationic modifiers and fluorine-containing water repellent treatment agents, and explores the impact of different fabric pretreatment modification schemes on the ink drop test results. Experiments are conducted on the use of the two separately or in combination. It is concluded that fabrics treated with 1% cationic modifier and 0.05% fluorinated water repellent separately can achieve the best results in the final form and color development of ink droplets. When two reagents are mixed at the optimal concentration, a synergistic effect that promotes each other can occur, which is superior to the effect of using each agent

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separately. It can suppress infiltration to a greater extent, have the best contour clarity and higher color depth, and achieve the best inkjet printing suitability.

References 1. Zhang, M.: Solution for digital printing enterprises to cope with environmental protection pressure. Print Today. 11, 46–48 (2020) 2. Editorial, D.: The current development trends and prospects of digital printing. Screen Printing Ind. 6, 17–18 (2020) 3. Li, M., Zhang, L.: Relationship between silk fabric pretreatment, droplet spreading, and ink-jet printing accuracy of reactive dye inks. J. Appl. Polym. Sci.Polym. Sci. 135, 45–46 (2018) 4. Zhao, T., Research on improving the printability of digital printing by fabric pretreatment. Tianjin Univ. Sci. Technol. (2021

Research on 3D Reconstruction Method of Damaged Object Based on Neural Network Wenpeng Sang, Maohai Lin(B) , Yaoshun Yue, and Kaiwei Zhai State Key Laboratory of Biobased Material and Green Papermaking, Faculty of Light Industry, Qilu University of Technology(Shandong Academy of Sciences), Jinan, China [email protected]

Abstract. In everyday life, there are many objects that hold special meaning to us. Sometimes, these objects may become damaged due to various reasons. To repair and restore these damaged objects, a proposed method involves using a three-dimensional laser scanner to capture point cloud data of the damaged object. This point cloud data is then inputted into a neural network for repair and reconstruction, resulting in a three-dimensional reconstructed point cloud data. The final step involves using model encapsulation and 3D printing to create a highly accurate replica of the object. To validate this method, it was tested on reconstructing objects such as a cube, teapot, and gypsum statue. The research results demonstrate that the three-dimensional reconstructed models have clear texture, complete shape, and are highly consistent with the original objects, thus fulfilling the purpose of object restoration. Keywords: Three-dimensional scanning · 3D printing · Neural network · Object repair · Three-dimensional reconstruction

1 Introduction Damaged objects are very common in daily life. Most of the time, replaceable objects can be easily replaced after being damaged. However, there are still many valuable objects that are difficult to repair or replace after being damaged. The problem we need to solve is how to accurately repair and restore damaged objects. The combination of 3D laser scanning, 3D reconstruction, and 3D printing can achieve high-quality restoration of damaged objects. Traditional 3D reconstruction can be divided into two categories: image-based 3D reconstruction and point cloud-based 3D reconstruction. Traditional 3D reconstruction methods have been studied for a long time and are relatively mature. They are widely used in the field of cultural heritage restoration. In 2004, Martin Campbell achieved 3D reconstruction of cultural artifacts by extracting geometric details of fragments and matching the pieces together [1]. In 2014, Sun Xiu’en and others studied the application of 3D digital reconstruction in the restoration of bronze artifacts, and reconstructed complete bronze artifact samples using fragments of bronze artifacts [2]. In 2017, Shu Huan and others used 3D reconstruction and 3D printing technology to perform stitching and © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 102–106, 2024. https://doi.org/10.1007/978-981-99-9955-2_15

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reconstruction on the Terracotta Warriors and Horses, improving the speed of restoration [3]. Although traditional 3D reconstruction methods have been widely used, but they require a significant amount of human resources for supervision due to the constraints of traditional machine learning methods in terms of learning methods and learning devices. Additionally, when faced with multiple shape modification and generation tasks, they are unable to accurately identify the geometric and topological differences in object shapes [4]. To address these issues, this paper proposes to invoke a novel neural network that combines neural networks with 3D scanning and 3D printing to realize highprecision repair and restoration of damaged objects. The point cloud data obtained from 3D scanning is convolved by the neural network, and the convolved point cloud data undergoes input and feature transformations. Point features are aggregated through max pooling, and the reconstructed point cloud data is output. Finally, the three-dimensional reconstruction model is obtained through encapsulation and printing [5].

2 Process and Method Research 2.1 3D Model Repair Process 3D model repair process is shown in Fig. 1. Firstly, the damaged object is scanned with a wiiboox Reeyee Pro 2X 3D laser scanner to obtain the point cloud data of the object. The acquired point cloud is processed by removing noise points and input into the neural network, and the point cloud of the damaged object undergoes coordinate transformation, feature calculation and segmentation in the neural network to output the reconstructed point cloud data. Finally, the reconstructed point cloud is encapsulated and 3D printed to obtain the 3D reconstructed model [6]. 2.2 Three-Dimensional Reconstruction The three-dimensional reconstruction method proposed in the article combines neural networks with 3D scanning and 3D printing to achieve high-precision repair and restoration of damaged objects. Initially, the point cloud obtained from the 3D scan is inputted to the neural network as data of size n × 3. Using the input data and T-Net, a 3 × 3 matrix is trained and applied to transform the coordinates of the input point cloud. This rotation aligns the input point cloud to a relatively stable space. The training process of the 3 × 3 matrix is illustrated in Fig. 2. The n × 64 features are obtained by training the multilayer perceptron (64,64) and each point is transformed from 3 features to 64 features. T-Net is again utilized to compute the 64 × 64 transformation matrix to get the features for each point. Then the multilayer perceptron (64,128,1024) is utilized to train to get n × 1024 features, and the point cloud is fused by Max Pooing to get the 1024-dimensional global features, and the multilayer perceptron processing is shown in Fig. 3.

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Fig. 1. 3D model repair flow chart

Fig. 2. Training a 3 × 3 matrix

Fig. 3. Multi-layer perceptual processing process

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The global features obtained from fusion are passed through multilayer perceptron (512, 256, k) to get k scores to complete the point cloud classification[7]. Finally, the local information of the point cloud n × 64 and the comprehensive information of the point cloud 1024 dimensions are simultaneously input into the segmentation network, and the new features obtained are passed through the two perceptron machines for point cloud segmentation, and the final output of the reconstructed point cloud is performed after learning prediction.

3 Experiment and Analysis In order to verify the feasibility of the experiment, this paper selects three objects as experimental models, the square, the teapot, and the plaster statue, and the missing parts of the three models are different, the square model lacks a plane, the teapot’s grip is missing, and the body part of the plaster statue is missing. The free surface of the three models gradually increases, and the difficulty of repairing increases in turn, which can play an obvious contrast effect. The three experimental models are scanned in three dimensions sequentially, and the point cloud data obtained from the scanning is input to the neural network, and the 3D reconstructed point cloud is obtained after the point cloud processing of the neural network, and the 3D reconstructed model of the object is obtained after the point cloud is encapsulated and 3D printed. The experimental results show that the 3D reconstructed point cloud can highly restore the shape of the object, and the texture of the encapsulated and printed model is clear and highly consistent with the shape of the original object, as shown in Table 1. Table 1. Various models in the experiment process

Experimental model

3D reconstruction of the point cloud

Encapsulation model

Three-dimensional reconstruction model

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By comparing the data in Table 2, it is evident that the reconstructed 3D model closely matches the original object, with minimal errors in terms of length, width, and height. The errors are generally controlled within 1%. These experimental results demonstrate that the damaged object can be accurately restored to high quality using the 3D reconstruction model. Table 2. Experimental comparison data Contrast object

Long Damaged object

Three-dimensional reconstruction model

Error

block

213.12 mm

211.34mm

Teapot

186.9 6mm

Gypsum statue

117.12 mm

Wide

Error

Damaged object

Three-dimensional reconstruction model

0.84%

171.23 mm

169.57mm

185.22mm

0.91%

130.86 mm

118.38mm

1.1%

109.07 mm

High

Error

Damaged object

Three-dimensional reconstruction model

0.97%

224.92 mm

223.34mm

0.7%

129.39 mm

1.1%

120.79 mm

120.08 mm

0.59%

109.92 mm

0.77%

200.97 mm

198.71 mm

1.1%

4 Conclusion In this paper, 3D scanning and 3D printing are combined with neural networks to create a 3D reconstruction of the damaged object’s point cloud. The 3D reconstruction model is then created by 3D printing. When compared to the original object, the model data obtained by 3D reconstruction is remarkably consistent, which makes it better suited for the restoration of damaged objects. The 3D reconstruction method suggested in this study is worth exploring and using in the high-precision repair and restoration of damaged things since many everyday goods with particular value are difficult to repair or replace after damage.

References 1. Sablatnig MKaR. 3D Puzzling of archaeological fragments. In: Proceedings of the 9th Computer Vision Winter Workshop, Computer Vision, pp. 31–40(2004) 2. Sun, X., Zhang, D., Sun, X.: Research on the application of 3D digital reconstruction in the restoration of bronzes. J. Graphics 35(06), 912–917 (2014) 3. Shu, H.: Application of 3D reconstruction and 3D printing in the restoration of Terracotta warriors. Electron. Sci. Technol. 4(04), 160–163 (2017) 4. Hou, M., Zhao, S., Yang, S., Hu, Y.: Research progress, challenge and development trend of virtual restoration of cultural relics with 3D model. Heritage Conserv. Stud. 3(10), 1–10 (2018) 5. Qi, CR., Su, H., Mo, K., Guibas, LJ. PointNet: Deep learning on point sets for 3D Classification and Segmentation. CoRR, abs/1612.00593(2016) 6. Liu, J., Sun, L., Li, Y.: The application of 3D printing technology in cultural relics protection. Sci. Technol. Style 06, 86–87 (2019) 7. Xie, L., et al.: Self-feature-based point cloud registration method with a novel convolutional Siamese point net for optical measurement of blade profile. Mech. Syst. Signal Process. 178, 109243 (2022). https://doi.org/10.1016/j.ymssp.2022.109243

Research Progress of 3D Printing Silicone Rubber Materials Yan Li1 , Kun Hu1(B) , Yongxiang Xu2(B) , Yanglan Pei1 , Zongwen Yang1 , Lu Han1 , Luhai Li1 , and Yen Wei3 1 Beijing Engineering Research Center of Printed Electronics, Institute of Printing and

Packaging Engineering, Beijing Institute of Graphic Communication, Beijing, China [email protected] 2 Department of Dental Materials, Peking University School and Hospital of Stomatology, Beijing, China [email protected] 3 Department of Chemistry, Tsinghua University, Beijing, China

Abstract. The rapid development of 3D printing technology and a series of polymer materials has made people’s daily life more convenient. 3D printing technology uses computer control to achieve fine, customized on-demand printing, which is not only resource-saving but also flexible and efficient. Silicone rubber is a polymeric silicone elastomer with a Si-O-Si bond in the main chain and an organic group in the side chain, which has high elasticity, high and low temperature resistance, aging resistance and excellent biocompatibility, and has been widely used in various fields such as biomedical, aerospace, mechanical engineering, and optoelectronic materials. Combining 3D printing technology with silicone rubber materials can not only broaden the scope of 3D printing technology, but also make better use of silicone rubber materials to provide convenience in daily life. This study mainly discusses the current development status of 3D printing silicone rubber materials and the future development direction. Keywords: 3D printing technology · Silicone rubber material · Multidimensional printing technology

1 Introduction Materials development is closely related to human life, involving all aspects of food, clothing, housing and transportation. It is due to the continuous innovation in materials, a large number of new materials have been developed and applied in daily life, which has greatly contributed to the development of modern society and the progress of human civilization. 3D printing technology has a significant feature of customization, which can meet the needs of different industries and fields. Since the industrial production of organochlorosilanes in the 1940s, after decades of development, a variety of silicone oil and Organosilicon related products up to more than five thousand varieties, application areas continue to broaden [1]. With China’s transformation into a manufacturing powerhouse and the steady implementation of national plans such as “One Belt, One © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 107–119, 2024. https://doi.org/10.1007/978-981-99-9955-2_16

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Road”, the market demand for silicones continues to grow and gradually replaces the stock market for other materials[2]. Based on the summary of the current development of 3D printing technology and silicone rubber materials, this study analyzes the feasibility of 3D printing silicone rubber technology and looks forward to the broad application prospects of this technology.

2 Types of 3D Printing Technology 3D printing can output geometric models into physical objects by means of continuous additive, which originates from the layer-by-layer manufacturing technology of 3D structures drawn directly by computer-aided design, and is a real technological innovation. 3D printing was first commercialized in 1980, and in recent years 3D printing technology has developed to a multifunctional stage, gradually playing an important role in the manufacturing industry. 3D printing technology has many advantages compared to traditional Manufacturing industry easy to operate, flexible and versatile, in reducing costs while also achieving better quality control, so 3D printing has been widely used in the world, agriculture, industry, medical industry are visible 3D printing products. But at the same time the application of this technology also has some disadvantages, which may reduce some manufacturing labor jobs and affect the economy of some countries that rely on low skills [3–5]. Depending on the printing principle, 3D printing technologies can be broadly classified into seven types: powder bed fusion, reduced photopolymerization, material inkjet, material extrusion, material jetting, sheet lamination, and energy deposition [6] (Fig. 1).

Fig. 1. Benefits of additive manufacturing

2.1 Powder Bed Fusion Powder bed fusion includes electron beam melting (EBM), selective laser sintering (SLS) and selective thermal sintering (SHS) printing techniques, which fuse material powders together with a laser or electron beam, and the powder material can be metals, ceramics, polymers, and composites. The printing process involves automatically targeting the laser at points created by the 3D model, binding the material and creating a solid structure.

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One of the main applications of powder-based 3D printing is selective laser sintering (SLS), which was developed by Carl Deckard in 1978. Powder bed fusion consists of three steps, powder deposition, laser sintering, and flat layer descent, in a process shown in Fig. 2. Unlike other 3D printing techniques, the powder in the non-sintered region of SLS can be recycled as a support material, resulting in nearly 100% material utilization [7–9].

Fig. 2. Schematic of the powder bed process

2.2 Vat Photopolymerization Reduction photopolymerization is generally the curing of photoreactive polymers using a specific laser or UV light. Common 3D printing technologies that use photopolymerization are stereolithography (SLA) and digital light processing (DLP) [10]. Reduced photopolymerization printers are similar to SLS printers, except that the light source and printing material are different. During the printing process, the light source makes the liquid photopolymer cured, and different thin layer patterns are formed by the movement of the light source. After printing one layer, the support plate moves one layer thickness to make the new liquid photopolymer flow into the printing area until the printing is completed. CAL is a new type of photoreductive 3D printing, which can achieve concurrent printing of all points within a 3D object by dynamically illuminating a rotating photosensitive material, as shown in Fig. 3 shows, this method prints much faster than layer-by-layer printing [11–13].The most important parameters of photopolymerization are exposure time, wavelength and power, which are suitable for fine production of high quality products. 2.3 Material Jet Printing Material jet printing is a three-dimensional manufacturing process that selectively deposits droplets to print physical objects. A common inkjet printing device is shown in Fig. 4, which usually contains an X-Y-Z three-axis motion platform, an inkjet head and a curing device. As the platform moves, the print head ejects the photosensitive material and cures the build section layer by layer under UV light. Inkjet printing can be divided into continuous inkjet printing (CIJ) and droplet-on-demand (DOD) printing [14, 15].

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Fig. 3. CAL volumetric fabrication.

Fig. 4. Schematic illustrations of different 3D printing technologies.

2.4 Material Extrusion Material extrusion is a manufacturing process in which material is extruded into a continuous wire through a nozzle and then selectively deposited into a target product. Extruded 3D printers contain devices similar to inkjet printers, which deposit extruded material on a flat surface to form a layer through the movement of XY axis, and print the next layer by moving the nozzle up or the platform down, and keep repeating to finalize the printing. Fused deposition molding (FDM) was the first extrusion printing method to emerge. Direct writing printing (DIW) is an important alternative to FDM when printing viscoelastic materials, as shown in Fig. 5 [16]. Viscoelastic inks are critical to the success of DIW, which requires the necessary rheological properties and good recovery to ensure continuous printing. Material extrusion technology can be used to print plastics, food and live cells and has been widely used.

Fig. 5. Schematic illustration of direct ink writing techniques

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2.5 Directional Energy Deposition Directional energy deposition is a relatively complex printing process that is often used to add additional material to an existing product or to repair a damaged product, with a high degree of control over grain structure and therefore good print quality. Directional deposition is similar in principle to material extrusion, but the nozzle can be moved in multiple directions. Examples of this manufacturing technology are laser deposition and laser engineered net forming (LENS). Laser deposition techniques can produce or repair parts on the millimeter to meter scale and are becoming increasingly popular in the transportation, aerospace, and oil and gas fields, with materials such as ceramics, polymers, metals, and metal-based hybrids available for practice [4, 17]. 2.6 Binder Jetting Binder jetting is an additive 3D printing process that uses a liquid binder to selectively fuse powdered materials, primarily for printing metallic materials. Binder jetting technology involves spraying a chemical binder onto a sprayed powder to form layers [18]. The application of sprayed binder is mainly to produce castings, raw sintered products or similar high volume products. In addition, the binder spraying process is simple, fast and inexpensive because the powder particles are stuck together and binder spraying also can print very large products. 2.7 Sheet Lamination Sheet lamination is the process of bonding thin sheets of material together to form a single unit and is primarily applied to paper or metallic materials. As defined by ASTM, sheet lamination is a 3D printing process in which thin sheets of material are bonded together to produce a part of an object [19]. Examples of 3D printing technologies that use this process are laminated object manufacturing (LOM) and ultrasonic additive manufacturing (UAM). The advantages of this process are that the laminate can be printed in full color, it is relatively inexpensive, and it is easy to recycle for material handling. Laminated Object Manufacturing (LOM) can print complex geometric parts with low cost of consumption and short operation time[20] . Ultrasonic Additive Manufacturing (UAM) uses sound to merge metal layers extracted from featureless foil stock. Adhesive injection technology uses liquid binders to selectively fuse powder materials and is mainly used to print metal and ceramic materials; sheet lamination technology is mainly applied to paper or metal materials; and energy deposition technology uses thermal energy to melt metal materials during the deposition process. Therefore, 3D printing of silicone rubber mainly uses several other printing technologies.

3 Silicone Rubber Material and Their Advantages The birth of silicones can be traced back to 1863, when scientists successfully synthesized tetraethylsilane containing silicon and carbon bonds, which laid the foundation for the research of silicones. In the 1940s, Dr. Rojo of General Electric proposed the “direct

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synthesis” of methylchlorosilane, and the successful application of this method promoted the industrial production of silicone materials. Silicone rubber is widely used in defense, industry, electronic components, biomaterials and medical devices, and has become an indispensable material. The molecular chains of silicone rubber are more flexible because the bond lengths and bond angles of silicon-oxygen bonds are greater than those of carbon-carbon single bonds, while the organic groups in the side chains further reduce the intermolecular forces. This flexibility allows silicone rubber to remain flexible at low temperatures, making it suitable for a wide range of applications such as sealing and packaging materials and insulation and fireproofing materials [21–23]. 3.1 High Temperature Resistance The high bonding energy of siloxane requires a large energy absorption to break the siloxane bond, so its performance remains stable at high temperatures. Under the effect of high temperature thermal oxidation, its main chain is rarely destroyed, and most of them are side chain organic groups broken. If from a microscopic point of view, heatresistant groups with large space-site resistance such as phenyl can be added to the main chain part of silicone rubber, which can prevent the main chain from breaking and rearranging and improve its high-temperature resistance[24]. 3.2 Low Temperature Resistance Silicone rubber has excellent high temperature resistance and also has good low temperature resistance, which is determined by a combination of factors. The molecular chain of silicone rubber has a high degree of free orientation, while the oxygen atom on the main chain is not connected to the substituent, resulting in a high degree of flexibility of the silicone rubber molecular chain, low glass transition temperature, in low temperatures can still maintain excellent elasticity and strength, that is, good low temperature resistance [25, 26]. 3.3 Physiological Inertia Silicone rubber side groups are usually non-polar methyl groups, which play a shielding and weakening role on the polarity of the main chain silicone oxygen bond, reducing the surface energy of silicone rubber, making silicone rubber has a good physiological inertia, is widely used in medical aesthetics, plastic surgery, artificial organs, artificial skin, artificial blood vessels and other human repair or medical fields [27]. The large number of silicone rubber materials used in the human body has also raised some safety issues, such as silicone rubber prosthesis will lead to the surrounding connective tissue lesions, whether the lesions are caused by the individual body rejection reaction or by the composition of different silicone rubber materials, there is no clear statement, but the long-term application of silicone rubber materials in vivo there is a certain risk of lesions. In order to reduce this risk of use, researchers have done a lot of research. AzizT used plasma to modify the surface of silicone rubber, and the modified silicone rubber has low water absorption, which can be used to prepare good wettability of

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facial prosthetic materials [28]; hydroxyapatite (HAP) has good biocompatibility and is widely used in artificial bone preparation, Mou Shansong et al. used 60% mass fraction of hydroxyapatite to improve high temperature The hemocompatibility of vulcanized silicone rubber was improved by hemolysis and coagulation experiments, which proved that the modified silicone rubber has good hemocompatibility [29]. 3.4 Hydrophobicity Silicone rubber is insoluble in water, and when it is immersed in water for a long time, it can only absorb about 1% of water, and its water contact angle is close to 90°, and water droplets cannot wet silicone rubber, so silicone rubber is a hydrophobic material. When silicone rubber is coated on other materials as a layer, the oxygen atoms on the main chain of silicone rubber are easily attracted to certain atoms on the surface of the coated material to form coordination bonds, making the coating more solid. The non-polar groups of the side chains of silicone rubber are arranged towards the outside, forming a surface layer of hydrophobic groups, which prevents water molecules from coming into contact with the inner polar bonds and can further improve the hydrophobicity of the coated substance [30].

4 3D Printing Silicone Rubber Material Silicone rubber materials have been widely used in medical, aerospace, automotive and other fields because of their good weather resistance, physiological inertness and other characteristics, but the processing and manufacturing process of silicone rubber materials is still mainly based on the casting method, which has the problems of single product form, long molding time and insufficient refinement of products, limiting the further application of silicone rubber materials in the fields of rapid prototyping, personalization and high precision processing. Combining 3D printing technology with silicone rubber, the advantages of flexible output, high precision and personalization of 3D printing are expected to solve the problems of silicone rubber in the above-mentioned market applications are limited, and the main printing technologies are currently focused on direct writing printing and light-curing printing. 4.1 3D Printed Silicone Rubber Industrial Applications Polydimethylsiloxane (PDMS) is flexible, translucent, chemically inert, and electrically insulating, allowing for easy soft lithographic replication and chip production. In addition PDMS is permeable to gases, which facilitates high transfer rates, thus making PDMS a suitable material for various membrane applications. For device fabrication by soft lithography, PDMS formulations are cast onto a mold and subsequently thermally cross-linked. After curing, the replica is simply peeled off the mold to restore the desired structure within the PDMS slab [31, 32]. The mold represents the desired shape of the substrate. Therefore, the geometry and fidelity of the replica depends on the quality of the mold and the removal technique, and is therefore usually limited to 2D designs with low complexity. Since the structure of the PDMS has to be recovered after replication,

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digital photoprocessing additive manufacturing can be applied to the 3D fabrication of PDMS photoresist materials [33]. T. Femmer et al. prepared a PDMS photoresist material that can print silicone structures of almost any geometry. By combining oligomethacryloxypropyl methicone with PDMS, the ink has 7–9 mol% methacrylate groups and a viscosity of 2–3 Pa·s, successfully achieving 3D printed PDMS with a resolution of 100 µm. The direct fabrication of 3D printed PDMS films using a common digital rapid prototyping machine is shown in Fig. 6, which has efficient gas transport properties. This molding method can directly produce 3D PDMS in a few hours, providing new geometries for a variety of devices with applied membranes [34].

Fig. 6. 3D-printed PDMS membrane contactor and artistic rendering of the respective TPMS structure (inset right). Gas flows horizontally from left to right while the bromothymol blue pH indicator is pµmped vertically from the bottom to the top through the contactor. The color change of the pH indicator from blue to yellow indicates the CO2

Professor Rigoberto C. Advincula’s research group has proposed a unique and versatile 3D printing solution that employs specially formulated polydimethylsiloxane (PDMS) inks and utilizes a salt immersion method to obtain higher porosity to print 3D models of silicone foam. The technology developed in this experiment has an adjustable structure and excellent performance to easily print designed frames that facilitate the development of a wide range of new functions and applications, including sensors, soft robotics, and biomedical materials. The 3D molding process is shown in Fig. 7 below, and the finished print is shown in Fig. 9 below [35–37] (Fig. 8).

Fig. 7. Schematic illustration of 3D printing trimodal porous silicone elastomer with complex architectures

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Fig. 8. (A) Illustration of hierarchical porosity in the 3D printed objects; (B) Optical images of 3D printed PDMS foam structures; (C.D) 3D printed PDMS foam of cubic cellular lattices and dogbone shaped cellular lattices

3D printing complex structures of silicone rubber is challenging because of its low modulus of elasticity and the need for support during printing, and the low viscosity of liquid oligomers makes it difficult to use in more advanced manufacturing methods. Embedded 3D printing is another DIW technique where the ink is extruded through a nozzle into a soft support matrix. J. Thoma et al. demonstrated 3D printing of hydrophobic PDMS prepolymer resin within a hydrophilic Carbopol gel carrier via free-form reversible embedding (FRE), Fig. 9.During the FRE printing process, the Carbopol support acts as a Bingham plastic when the 3D printer’s syringe tip moves through it, it is created and fluidized, and for the PDMS extruded in it, it acts as a solid. After printing and curing, the Carbopol support gel is released from the embedded PDMS print by using a phosphate-buffered aqueous solution to reduce Carbopol yield stress. Using Sylgard 184 PDMS to 3D print linear and helical filaments by continuous extrusion and 3D printing cylindrical and helical tubes by layer-by-layer fabrication, the resulting 3D printed catheters are multi-branched and potable. This demonstrates that hydrophobic polymers with low viscosity and long cure times can be 3D printed using hydrophilic carriers, thus expanding the range of biomaterials that can be used for additive manufacturing. Furthermore, by implementing the technology using low-cost open-source hardware and software tools, FRE printing technology can be quickly implemented for research applications [38].

Fig. 9. FRE printing is performed by extruding PDMS prepolymer in a support bath consisting of Carbopol gel.

4.2 3D Printed Silicone Rubber Medical Applications Fripp Design has developed a silicone 3D printer called Picsima, which integrates powder bed 3D printing with light-curing 3D printing. The catalyst is mainly used to sinter or

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cure a “material pool” filled with a special silicone oil, and the 3D printer’s needle extruder head sprays a quantitative amount of catalyst into the silicone oil surface layer by layer. Picsima silicone 3D printers can print silicone objects up to 100 * 100 * 30 mm in size, with layer thicknesses as fine as 0.4 mm and Shore hardnesses as low as 10 A, and have been approved by the FDA for use in the medical and food fields, and are widely used in the printing of prosthetic ears, noses and dentures. It is widely used in the printing of prosthetic ear, nose and denture, as shown in Fig. 10 below.

Fig. 10. Picsima 3D printed ears, silicone nose, silicone earbuds

The University of Florida (UF) has developed a new liquid silicone 3D printing technology. The technology allows for the production of softer, stronger and more affordable catheters, implants and other medical devices. The most important feature of the technology is that it can be printed in a liquid, which is an oily organic compound formed by mixing a light mineral oil with a gel that can support the printed product, and the 3D molding process is shown in Fig. 11 below [39].

Fig. 11. Liquid silicone 3D printing technology

Researchers investigated the feasibility of 3D printing of human heart models for simulated surgery or training using an extrusion apparatus and a low-cost FDM printer combined with thermoplastic polydimethylsiloxane (PDMS) with high transparency, flexibility, and resistance to a wide range of reagents.To improve the print and simulate the sticky-slip effect of living organs, sodium carboxymethylcellulose (Na-CMC) protofibers, pure PDMS and composite Na-CMC/PDMS filaments used in FDM are shown in Fig. 12 below. However, this caused intermittent blockage of the nozzle, making FDM3D printing difficult [40]. Despite not achieving the desired goal, this article presents a possible solution for printing fully characterized Na-CMC/PDMS composites [41].

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Fig. 12. (A) the neat PDMS and composite Na-CMC/PDMS filaments used in FDM; SEM images, at different magnification, of (B) the composite filament printed in layers.

5 Outlook 3D printing material diversification is the current development trend of 3D printing, from the original ink to the current polymer materials, ceramic materials, and even biological cells can be used as the ink for printing, which can print products with three-dimensional structure and stimulation response. 3D printing has been used in many fields after years of development, such as construction, manufacturing, etc. but the limitations of printing materials and printing precision 3D printing still has some problems that need to be solved urgently. In the future, we should start with the development of new printing materials and new printing machines, combined with water, sound, light, electricity, biochemical stimulation, the development of 4D-ND multi-dimensional printing high-tech. Taking multidimensional printing silicone rubber as an example, intelligent multidimensional printing silicone rubber materials can be designed for the field of intelligent packaging, and the silicone rubber will make corresponding changes when the external environment changes in order to protect the precious foreign objects it wraps, etc. Smart packaging is just one of the future applications of silicone rubber up-dimensional printing products, which can also be applied to biomedicine, aerospace, intelligent manufacturing and other industries and fields. In the end, the continued flourishing of multifunctional printing products will help solve the difficulties and challenges faced by many fields. Acknowledgements. This research was supported by the Beijing Institute of Graphic Communication R&D Project-Research on Pressure Sensing Antibacterial Polyester Urethral Stent (Ee202207), Innovation projects in incubating technology enterprises-Study on the cell compatibility of new cerebrovascular drug-eluting stent (2021-F-057), Education Reform Project of Beijing Higher Education Association: An Exploration of Teaching Reform centered on the cultivation of Students’ Creative ability under the concept of Universal Printing (MS2022178).

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Research Progress of Artificial Vertebral Body and Interbody Fusion Cage Zongwen Yang1 , Kun Hu1(B) , Peng Li2(B) , and Xiangqian Xu3 1 School of Printing and Packaging Engineering, Beijing Institute of Graphic Communication,

Beijing 102600, China [email protected] 2 State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, CAS, Beijing, China [email protected] 3 Huarui (Fujian) Biotechnology CO. Ltd, Fujian, China

Abstract. The objective is to review the latest research on artificial vertebral body and interbody fusion cage and their application in spinal surgery. For the treatment of vertebral diseases such as spinal tumors and myelopathic cervical spondylosis, procedures like en bloc tumor resection and intervertebral disc excision with bone fusion are primarily employed. Following tumor resection surgery, it becomes necessary to reconstruct the deficient vertebral segments or intervertebral discs. In clinical practice, materials such as titanium alloys, PEEK, and ceramics are commonly used to manufacture artificial vertebral bodies and interbody fusion cage for vertebral reconstruction. Currently, the use of 3D printing for fabricating implantable metal medical devices, including 3D-printed titanium alloy or PEEK vertebral implants and interbody fusion cage, is gradually gaining prominence. This article reviews the latest research on artificial vertebral bodies and intervertebral fusion devices in recent years. Keywords: Artificial vertebral body · Interbody fusion cage · 3D printed titanium alloy · Vertebral reconstruction

1 Introduction In recent years, the incidence of spinal tumors has been gradually increasing. Spinal tumors can lead to defects in the anterior column of the vertebral body, resulting in spinal instability, compression of nerves and spinal cord, and other symptoms, which can have a significant impact on the physical and mental well-being of patients. Vertebral tumors include various types such as plasmacytoma, osteosarcoma, vascular tumors, and metastatic tumors, with the incidence of metastatic tumors currently much higher than that of primary bone tumors [1]. The treatment of spinal tumors mainly includes vertebral augmentation, partial resection of the tumor with decompression, and en bloc resection of spinal tumors [2]. In 1969, Hamid [3] first reported the use of artificial vertebral bodies to fill the defects © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 120–127, 2024. https://doi.org/10.1007/978-981-99-9955-2_17

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after resection of diseased vertebrae, which showed good clinical outcomes and led to rapid development of artificial vertebral bodies. The shapes of the cervical, thoracic, and lumbar vertebrae vary, and the required sites and shapes of vertebral reconstruction vary depending on the different locations of lesions and tumor sizes in different patients. Zhu et al. [4] suggested that intervertebral disc prostheses should be designed separately for different segments to accommodate morphological and biomechanical changes. Robinson and Smith [5] proposed the use of horseshoe-shaped cortical bone as implants for ACDF surgery, achieving a clinical success rate of 71% at that time. As research progressed, autogenous bone, allograft bone, artificial ceramic bone, and other materials were gradually used [6]. Currently, titanium mesh cages (TMC) made of PEEK or titanium alloy are commonly used as artificial vertebral bodies, and interbody fusion cage are manufactured using PEEK or titanium alloy materials. However, the elastic modulus of solid titanium alloy materials is much higher than that of natural bone, which can induce stress shielding effects and affect bone fusion [7]. With the rapid development of 3D printing technology, the production of artificial vertebral bodies and interbody fusion cage using metal powders or polymer materials through 3D printing has become increasingly mature. For example, collagen, hydroxyapatite, PEEK, and other bone materials can be printed into bone scaffolds or blocks using fused deposition modeling (FDM) technology. Electron beam melting (EBM), selective laser sintering (SLS), laser metal deposition (LMD), and other powder printing technologies can be used to print titanium alloys, tantalum, nylon, ceramics, and other metal or polymer powders into bone implants. The technology for designing and manufacturing artificial implants through 3D printing has also become increasingly mature, and 3D printed artificial implants have gradually been applied in clinical practice [8–10]. Currently, there is a wide variety of materials used for manufacturing artificial vertebral bodies and interbody fusion cage, including biocompatible alloys such as titanium alloy and cobalt-chromium alloy, hydroxyapatite, mineralized collagen, biologically inert PMMA, PEEK, carbon fiber, porous materials, composite materials, and bioabsorbable materials [11, 12].

2 Research Status of Artificial Vertebral Bodies and Interbody Fusion Devices 2.1 Titanium Mesh Cages Currently, autogenous bone titanium mesh cages (TMC) remain the main implants used in ACCF and are also commonly used in TES surgeries. In transforaminal lumbar interbody fusion (TLIF) procedures, PEEK fusion cages are widely used, but titanium mesh cages have been reported to have higher fusion rates and subsidence rates [13]. TMC is typically a titanium alloy hollow mesh structure that can be trimmed according to the required length, providing good support. However, the point contact between TMC and the upper and lower endplates can lead to stress concentration, resulting in the subsidence of the titanium mesh, and in severe cases, collapse or spinal deformity [14, 15]. Currently, many studies are exploring ways to reduce the subsidence rate of TMC.

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Ji et al. [7] conducted a study on ACCF surgery and found that the contact between TMC (titanium mesh cage) and the endplate is point contact, which increases local pressure and easily leads to TMC subsidence, resulting in foraminal stenosis, compression of the spinal cord, and compression of nerve roots. They investigated the main risk factors for TMC subsidence and found that RAE (ratio of anterior endplate) > 1.18, TMC arrangement, and low bone density are risk factors for subsidence. Toshiya et al. [16] used titanium mesh cages with autogenous bone grafts for the treatment of pyogenic vertebral osteomyelitis (PVO) in thoracic or lumbar vertebral interbody fusion through the transforaminal approach. They achieved good bone fusion and therapeutic effects after surgery. Tenny et al. [17] reported a case of spinal cord tumor treated with cervical C2C3 vertebral body en bloc resection and reconstruction using a titanium mesh cage. Due to the complexity of cervical reconstruction surgery and the need for complete removal of C2, C3, and intervertebral discs between the two adjacent vertebral bodies, a large reconstruction range and long implant length were required, making the implantation challenging. Through careful preoperative planning, the tumor was successfully removed, and reconstruction was performed. Hangyu Ji et al. [18] investigated the clinical use and radiographic results of three types of TMC in cervical cervical spondylotic myelopathy. The three types of TMC were without endplate cover, with a traditional endplate cover, and with a new endplate cover, and the relationship between postoperative subsidence and TMC endplate covers was explored. The results showed that the new endplate cover significantly reduced postoperative subsidence, and the size of the endplate cover had a significant impact on the degree of subsidence. 2.2 Expandable Prosthesis Titanium mesh implants can be cut to the desired height, but other types of implants often lack this feature and require customization for different heights and widths. Expandable implants address this pain point by allowing height or angle adjustments to accommodate different needs [19]. Juan J. Ramı´rez et al. [20] designed an expandable vertebral body implant with a dual-cage plate structure (JR implant). The design of the JR implant makes it easy to place and provides significant durability, offering mechanical support to reconstruct spinal stability after vertebral resection surgery. Expandable implants are favored because of their better defect adaptability, as a single implant can be adjusted to fit various implant sizes. Compared to titanium mesh cages, expandable implants have better shape adaptability, but they also carry the risk of subsidence. The therapeutic outcomes may vary among different designs of expandable implants [21]. Paola et al. [22] found that the use of expandable interbody fusion cages in minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) significantly reduced the rate of subsidence compared to non-expandable fusion cages. Josha et al. [23] evaluated and compared the treatment outcomes of expandable and static interbody fusion cages for degenerative spinal diseases. The results showed that expandable lumbar interbody fusion cages implanted through minimally invasive surgery were a safe and effective

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treatment method, contributing to the restoration of anterior and posterior disc heights and reduction of vertebral slip. However, Armocida et al. [24] found in their comparison of expandable and non-expandable interbody fusion cages used in MIS-TLIF surgery that expandable implants posed a higher risk of subsidence without demonstrating better clinical outcomes. In disc reconstruction, multiple interbody fusion cages can be simultaneously implanted, and a similar approach can be applied to vertebral body reconstruction. Kwok et al. [25] described a new reconstruction method involving the implantation of two smaller expandable implants. This method provides sufficient stability while minimizing spinal cord compression and the risk of injury during the implantation process. 2.3 3D Printed Titanium Alloy Implants Although solid titanium alloy has a high modulus of elasticity, 3D printing can create titanium alloy materials with a multi-void structure that mimics the trabecular structure of natural bone. This allows for achieving a modulus of elasticity similar to natural bone while maintaining structural stability, minimizing stress shielding effects, and promoting bone ingrowth through a rough surface and appropriate porosity [26]. Wang et al. [27] conducted a comparative study by grouping 3D printed titanium alloy artificial vertebral bodies and interbody fusion devices with traditional TMC. The study showed that the use of 3D printed artificial vertebral bodies and interbody fusion devices in the treatment of multi-segment myelopathic cervical spondylosis using ACCF combined with ACDF achieved similar clinical outcomes to TMC and cages. Additionally, the surgery time was shorter, the interface between the material and bone was better, and there was less implant subsidence. Zhang Ya [28] conducted a surgical and postoperative observation study on patients who underwent vertebral body reconstruction using 3D printed titanium alloy artificial vertebral bodies after TES surgery. The study found that 3D printed titanium alloy artificial vertebral bodies provided better stability and less subsidence compared to titanium cages after en bloc resection of lumbar and thoracic spinal tumors. The porous structure and rough surface of the titanium alloy artificial vertebral bodies facilitated bone ingrowth. The porous structure of artificial vertebral bodies promotes fluid flow, facilitates migration and proliferation of bone cells, and a porosity rate of 70–80% is most conducive to bone ingrowth. Additionally, the rough surface structure promotes the differentiation of osteogenic cells [29]. Zhuan et al. [30] used electron beam melting technology to print titanium alloy artificial vertebral bodies as implants, and used patient CT data for personalized design and modification, and customized vertebral prostheses of appropriate shape and size for patients for the treatment of primary and metastatic spinal tumors, and achieved satisfactory results. 3D printed vertebral bodies can be designed with a porous structure similar to natural bone tissue, which facilitates bone cell ingrowth and fusion between the vertebral body and the implant. Amini et al. [31] compared the fusion effects of a novel 3D printed titanium interbody fusion device and a PEEK interbody fusion device in lateral lumbar interbody fusion (LLIF) surgery. The study found that the postoperative subsidence rate of the titanium metal interbody fusion device was significantly lower than that of the PEEK material interbody fusion device.

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2.4 Other Material Types Prostheses In addition to titanium mesh cages and 3D printed titanium alloy implants, there are currently various materials and structures used for vertebral body implants and interbody fusion devices. These include hydroxyapatite-based materials, PEEK materials, collagen, and others. Currently, PEEK implants dominate the market. PEEK has a similar stiffness to natural bone, but due to its hydrophobic nature, it does not promote fusion. Therefore, PEEK implants are generally hollow structures filled with autogenous bone grafts to achieve interbody bridging between vertebral endplates [32]. In natural bone, organic components provide toughness, while inorganic components provide strength [33]. The organic fraction accounts for approximately 30% and consists mainly of collagen fibers, primarily type I collagen [34]. The inorganic fraction accounts for over 60% and is primarily composed of hydroxyapatite, along with tricalcium phosphate and octacalcium phosphate, which are calcium phosphate-based minerals [35]. Hydroxyapatite, one of the main components of human bone, has been used in the field of biomedical applications for several decades [36]. Collagen protein, due to its excellent biodegradability and favorable biological properties, is also used as a matrix for bone materials [37]. Soichiro et al. [38] studied the preparation of bone implants using hydroxyapatite/collagen composite materials and experimentally demonstrated that hydroxyapatite/collagen implants with absorbed rhBMP-2 (recombinant human bone morphogenetic protein-2) can reduce implant subsidence and promote the formation of bone bridging compared to hydroxyapatite/collagen implants. Chen et al. [39] designed a novel highly adjustable artificial vertebral body (AHVB) by modifying nano-hydroxyapatite/polyamide 66 (n-HAP/PA66). PA66 has good stiffness and strength, while hydroxyapatite is a major inorganic component of human and animal bones, exhibiting good biocompatibility and being an ideal material for bone tissue engineering [40]. Jeongik Le et al. [41] designed a polyether ether ketone intervertebral fusion device with four openings at the front end, and the fusion device was inserted into the autogenous bone through the four openings, that is, the fusion device was placed into the fusion device from the upper and lower sides and the left and right sides respectively. Autogenous bone. The resulting overall fusion rate was 86.2%, within the range of 74%–94% reported in previous studies.

3 Conclusion The market for artificial vertebral body implants and interbody fusion devices is highly significant. Currently, the mainstream options in the market are expandable implants made of PEEK and titanium alloy interbody fusion devices. Summarizing the cuttingedge research, it is found that 3D printed titanium alloy implants and interbody fusion devices are moving from research and development towards clinical applications, with tremendous future market potential. They exhibit excellent mechanical properties, promote bone fusion, and the 3D printing manufacturing method allows for easy customization. On the other hand, research related to titanium mesh cages indicates that even with

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changes in their contact structure with the vertebral endplates, there has not been a significant improvement in subsidence rates. Acknowledgement. This study was supported by the Beijing Institute of Graphic Communication R&D Project-Research on Pressure Sensing Antibacterial Polyester Urethral Stent (Ee202207), Innovation projects in incubating technology enterprises-Study on the cell compatibility of new cerebrovascular drug-eluting stent (2021-F-057), Education Reform Project of Beijing Higher Education Association: An Exploration of Teaching Reform centered on the cultivation of Students’ Creative ability under the concept of Universal Printing (MS2022178).

References 1. Joubert, C., et al.: Corpectomy and vertebral body reconstruction with expandable cage placement and osteosynthesis via the single stage posterior approach: a retrospective series of 34 patients with thoracic and lumbar spine vertebral body Tumors. World Neurosurg. 84(5), 1412–1422 (2015) 2. Cianfoni, A., Massari, F., Ewing, S., Persenaire, M., Rumboldt, Z., Bonaldi, G.: Combining Percutaneous pedicular and extrapedicular access for Tumor ablation in a thoracic vertebral body. Interv. Neuroradiol. 20(5), 603–608 (2014) 3. Hamdi, F.A.: Prosthesis for an excised lumbar vertebra: a preliminary report. Can. Med. Assoc. J. 100(12), 576–580 (1969). PMID: 5775083; PMCID: PMC1945789 4. Zhu, Y.H., Cheng, K.L., Zhong, Z., Li, Y.Q., Zhu, Q.S.: Morphologic evaluation of Chinese cervical endplate and uncinate process by three-dimensional computed tomography reconstructions for helping design cervical disc prosthesis. J. Chin. Med. Assoc. 79(9), 500–506 (2016) 5. Smith, G.W., Robinson, R.A.: The treatment of certain cervical-spine disorders by anterior removal of the intervertebral disc and interbody fusion. JBJS 40(3), 607–624 (1958) 6. Huang, H., et al.: A critical review on the biomechanical study of cervical interbody fusion cage. Med. Novel Technol. Devices 11 (2021) 7. Ji, C., Yu, S., Yan, N., et al.: Risk factors for subsidence of titanium mesh cage following single-level anterior cervical corpectomy and fusion. BMC Musculoskelet. Disord. 21(1), 32 (2020). https://doi.org/10.1186/s12891-019-3036-8 8. Zuniga, J.M.: 3D printed antibacterial prostheses. Appl. Sci. 8(9), 1651 (2018). https://doi. org/10.3390/app809165112 9. Vannucci, J., Scarnecchia, E., Potenza, R., Ceccarelli, S., Monopoli, D., Puma, F.: Dynamic titanium prosthesis based on 3D-printed replica for chest wall resection and reconstruction. Transl. Lung Can. Res. 9(5), 2027–2032 (2020) 10. Denour, E., Eyen, S.L.: Emerging applications of 3D printed microporous prosthesis in nonunion repair: mechanisms and therapeutic potential. Ann. Transl. Med. 10(24) (2022) 11. Young, J.S., McAllister, M., Marshall, B.M.: Three-dimensional technologies in chest wall resection and reconstruction. J. Surg. Oncol. 127, 336–342 (2023) 12. Groot, A.L.W., Remmers, J.S., Hartong, D.T.: Three-dimensional computer-aided design of a full-color ocular prosthesis with textured iris and sclera manufactured in one single print job. 3D Print. Addit. Manuf. 8(6), 343–348 (2021) 13. Coban, D., et al.: Peek versus titanium cages in transforaminal lumbar interbody fusion: a 2-year follow-up study with clinical and radiological outcomes. Brain Spine 1 (2021) 14. Chen, Y., et al.: Subsidence of titanium mesh cage a study based on 300 cases. J. Spinal Disord. Tech. 21(7), 489–492 (2008)

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15. Chou, Y.C., et al.: Efficacy of anterior cervical fusion: comparison of titanium cages, polyetheretherketone (PEEK) cages and autogenous bone grafts. J. Clin. Neurosci. 15(11), 1240–1245 (2008) 16. Tachibana, T., et al.: Interbody fusion with cages for pyogenic vertebral osteomyelitis. J. Clin. Neurosci. 77, 191–194 (2020) 17. Tenny, S.O., et al.: Marginal en bloc resection of C2-C3 chordoma with bilateral vertebral artery preservation and mesh cage reconstruction with review of previously published cases. World Neurosurg. 108, 993e1–993e7 (2017) 18. Ji, H., et al.: Comparative analysis of three types of titanium mesh cages for anterior cervical single-level corpectomy and fusion in term of postoperative subsidence. Am. J. Transl. Res. 12(10), 6569–6577 (2020) 19. Skaggs, D.L., et al.: A classification of growth friendly spine implants. J. Pediatric Orthopaedics 34(3), 260–274 (2014) 20. Ramirez, J.J., et al.: An expandable prosthesis with dual cage-and-plate function in a single device for vertebral body replacement: clinical experience on 14 cases with vertebral Tumors. Arch. Med. Res. 41(6), 478–482 (2010) 21. Kwok, J.K.S., et al.: Multi-dimensional printing in thoracic surgery: current and future applications. J. Thorac. Dis. 10, S756–S763 (2018) 22. Calvachi-Prieto, P., et al.: Expandable versus static cages in minimally invasive lumbar interbody fusion: a systematic review and meta-analysis. World Neurosurg. 151, e607–e614 (2021) 23. Woodward, J., et al.: Expandable vs. static transforaminal lumbar interbody fusion cages: 1-year radiographic parameters and patient reported outcomes. World Neurosurg. (2021) 24. Armocida, D., et al.: Minimally invasive transforaminal lumbar interbody fusion using expandable cages: increased risk of late postoperative subsidence without a real improvement of perioperative outcomes: a clinical monocentric study. World Neurosurg. 156, e57–e63 (2021) 25. Kwok, M., et al.: Dual expandable interbody cage utilization for enhanced stability in vertebral column reconstruction following thoracolumbar corpectomy: a report of two cases. North Am. Spine Soc. J. (NASSJ) 8 (2021) 26. El-Hajje, A., et al.: Physical and mechanical characterisation of 3D-printed porous titanium for biomedical applications. J. Mater. Sci.-Mater. Med. 25(11), 2471–2480 (2014) 27. Wang, Z., et al.: Effectiveness of three-dimensional printing artificial vertebral body and interbody fusion Cage in anterior cervical surgery. Chin. J. Reparative Reconstr. Surg. 35(9), 1147–1154 (2021) 28. Zhang, Y., et al.: Application of 3D-printed individual artificial vertebral body in reconstruction of thoracolumbar Tumor after total en-bloc spondylectomy. Orthopaedic Biomech. Mater. Clin. Study 18(1), 17–21, 26 (2021) 29. Sidambe, A.T.: Biocompatibility of advanced manufactured titanium implants - a review. Materials 7(12), 8168–8188 (2014) 30. Zhuang, H., et al.: Assessment of spinal tumor treatment using implanted 3D-printed vertebral bodies with robotic stereotactic radiotherapy. Innovation (N Y) 1(2), 100040 (2020) 31. Amini, D.A., et al.: Evaluation of cage subsidence in standalone lateral lumbar interbody fusion: novel 3D-printed titanium versus polyetheretherketone (peek) cage. Brain Spine 1 (2021) 32. Loenen, A.C.Y., et al.: Early bone ingrowth and segmental stability of a trussed titanium cage versus a polyether ether ketone cage in an ovine lumbar interbody fusion model. Spine J. (2021) 33. Fantner, G.E., et al.: Sacrificial bonds and hidden length dissipate energy as mineralized fibrils separate during bone fracture. Nat. Mater. 4, 612–616 (2005)

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34. Niu, X.F., et al.: Calcium concentration dependent collagen mineralization. Mater. Sci. Eng. C 73, 137–143 (2017) 35. Niu, X., Feng, Q., Wang, M., Guo, X., Zheng, Q.: Porous nano-HA/collagen/PLLA scaffold containing chitosan microspheres for controlled delivery of synthetic peptide derived from BMP-2. J. Contr. Release 134, 111–117 (2009) 36. Xing, F., et al.: Chitin-hydroxyapatite-collagen composite scaffolds for bone regeneration. Int. J. Biol. Macromol. 184, 170–180 (2021) 37. Oosterlaken, B.M., Vena, M.P., de With, G.: In vitro mineralization of collagen. Adv. Mater. 33(16), e2004418 (2021) 38. Itoh, S., et al.: Development of an artificial vertebral body using a novel biomaterial, hydroxyapatite/collagen composite. Biomaterials 23(19), 3919–3926 (2002) 39. Chen, G., et al.: A novel height-adjustable nano-hydroxyapatite/polyamide-66 vertebral body for reconstruction of thoracolumbar structural stability after spinal Tumor resection. World Neurosurg. 122, e206–e214 (2019) 40. Wang, H., et al.: Research progress of hydroxyapatite bone tissue engineering materials. Shandong Chem. Ind. 50(9), 59–60 (2021) 41. Lee, J., et al.: Anterior bridging bone in a newly designed cage for lumbar interbody fusion: radiographic and finite element analysis. World Neurosurg. 154, e389–e397 (2021)

Preparation and Performance Test of 3D Printed Titanium Alloy Intervertebral Fusion Cage Zongwen Yang1 , Kun Hu1(B) , Peng Li2(B) , and Xiangqian Xu3 1 School of Printing and Packaging Engineering, Beijing Institute of Graphic Communication,

Beijing, China [email protected] 2 State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, CAS, Beijing, China [email protected] 3 Huarui (Fujian) Biotechnology CO., Ltd., Fujian, China

Abstract. The development of 3D printing technology has brought more methods for vertebral body weight construction. Titanium alloy has high specific strength and good biocompatibility, and 3D printed titanium alloy interbody fusion device currently has obvious advantages in vertebral body weight construction. The mechanical properties of titanium alloy interbody fusion with mesh structure prepared by Electron beam melting (EBM) were studied. Computer software was used to assist the design and modeling, the model was sliced and then imported into the EBM printer. After printing, the model was post-processed, the surface was characterized by scanning electron microscopy, and the mechanical properties such as dynamic torsion, dynamic compression shear and dynamic axial compression of the sample were tested by different types of fatigue testing machines. Keywords: Electron beam melting technology · Vertebral body reconstruction · Intervertebral fusion cage · Fatigue test

1 Introduction For the treatment of spinal diseases such as spinal tumors and myelopathic cervical spondylosis, surgical procedures are often required to remove the diseased area and reconstruct the spine, such as vertebral augmentation, partial removal of tumor through laminectomy, and en bloc resection of spinal tumors. This also includes surgeries like anterior cervical discectomy and fusion (ACDF) and anterior cervical corpectomy and fusion (ACCF) for myelopathic cervical spondylosis [1]. Interbody fusion devices and vertebral implants are used in the postoperative spinal reconstruction. The role of interbody fusion devices is to provide additional stability, allowing proper healing of the vertebral bone after surgery. They also help maintain the height of the intervertebral space and alleviate symptoms of nerve root compression and spinal cord compression [2]. Titanium alloy is lightweight, has high strength, corrosion resistance, and excellent biocompatibility, making it an ideal material for implantable devices and an important © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 128–135, 2024. https://doi.org/10.1007/978-981-99-9955-2_18

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focus of implant materials in recent years. However, solid titanium alloy (Ti6Al4V) has an elastic modulus as high as 100 GPa, which is much higher than the 10–30 GPa range of bone tissue in the vertebral region. The excessively high elastic modulus of solid titanium alloy can cause a “stress-shielding effect” at the bone-implant interface, leading to bone resorption near the implant and potentially causing loosening, instability, or even fracture of the titanium alloy implant [3, 4]. Electron Beam Melting (EBM) 3D printing technology, developed in the mid-1990s, is a type of 3D printing technology characterized by high energy utilization, nonreflectivity, high power density, fast scanning speed, pollution-free vacuum environment, and low residual stress [5, 6]. EBM has strong melting capability, low residual stress, and does not require post-processing. However, EBM has lower accuracy in forming, resulting in a relatively rough surface of the formed object. This “disadvantage” becomes an important advantage in the medical field as the rough surface increases the relative surface area, promoting cell and tissue adhesion and improving the biocompatibility of implants [7]. This article aims to explore the fatigue performance of EBM 3D-printed titanium alloy interbody fusion devices with special porous structures through mechanical testing.

2 Materials and Methods 2.1 Sample Processing Designing an intervertebral fusion implant model using software and modifying it to incorporate a dodecahedral rhombic lattice structure, achieving a sample porosity of 72%. Print the model using an EBM printing system (Arcam, Sweden) and Ti-6Al-4V powder with an average particle size of approximately 70 μm. After printing, perform sandblasting to remove excess powder from both the surface and the interior. 2.2 Structural Characterization After applying a gold coating to the sample using an ion sputter coater, observe the surface morphology using a scanning electron microscope (Hitachi SU-8000, 10 kV) and perform energy-dispersive X-ray spectroscopy (EDS) to scan the surface for elemental distribution. 2.3 Fatigue Test The experiment involves the use of different testing machines for various performance tests on the samples. The Dynamo-T40 fatigue testing machine is used for dynamic torsional performance testing and static torsional performance testing. The Fatig-AECO101 fatigue testing machine is used for dynamic shear performance testing and dynamic compression performance testing. The AGS-X-300 kN electronic universal testing machine is used for dynamic shear performance testing, static compression performance testing. Six samples of vertebral fusion devices are tested in the static testing group, while five samples are tested in the dynamic testing group. The corresponding intervertebral disc

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height for the vertebral fusion device is approximately 4mm. The testing environment is maintained at a temperature of 25 ± 5 °C and humidity of 40 ± 10%. The experimental test method was carried out according to YY/T 0959-2014 standard.

3 Results and Discussion 3.1 Structural Characterization The microscopic surface formed by EBM 3D printing can be seen after SEM imaging of the interbody fusion device, as shown in Fig. 1a. Unlike other implants, the micro-rough surface of interbody fusion device has a certain improvement in interbody fusion device performance, and the surface of the sample printed by EBM titanium alloy also has excellent stability. Figure 1(b) displays the energy spectrum of the sample surface, while Table 1 provides quantitative data for the elements in the energy spectrum, with all element data normalized. Due to prior processes such as polishing and platinum spraying, the sample surface contains trace amounts of carbon (C) and platinum (Pt) elements.

a.SEM image of the sample

b.Energy spectrum of the sample

Fig. 1. SEM image and energy spectrum

Table 1. EDS energy spectrum element content test data Element

Weight (%)

Atomic (%)

CK

4.23

14.84

Al K

5.39

8.42

Ti K

82.35

72.47

VK

4.14

3.42

Pt M

3.89

0.84

Total

100.00

100.00

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3.2 Fatigue Test Dynamic Torsion Performance Testing. Dynamic torsion performance testing was conducted using PEEK as the testing pad material to simulate the contact between the bone and the vertebral fusion device, eliminating the influence of bone properties and morphological variations. A total of six test samples were used, with three different loads applied. The testing was performed using a sinusoidal waveform (frequency of 5 Hz) with an angular displacement offset of 2.3°. The test results, as shown in Table 2, indicate that two samples achieved five million cycles of dynamic torsion testing under ± 2.1 N·m test conditions, while the remaining four experienced varying degrees of mechanical failure. Table 2. Dynamic torsional performance test data of the sample Number

Torsional load (N·m)

Cycles

DN-1

±2.1

5000001

DN-2

±2.1

5000001

DN-3

±2.7

2567762

DN-4

±2.7

1596063

DN-5

±2.9

1630629

DM-6

±2.9

2258927

Dynamic Shear Performance Testing. Dynamic shear performance testing was conducted using a sinusoidal waveform with a frequency of 5 Hz, and polyoxymethylene blocks were used as testing pads. The use of polyacetal blocks matching the geometry of the sample to simulate the vertebra was done to avoid wear caused by changes during the test and to eliminate the effects of bone characteristics and morphological diversity. The test results, as shown in Table 3, revealed that within the 206–2059 N range, all samples maintained their shape after five million shear cycles. However, the samples in the 360–3604 N range had the fewest cycles, and their cycle count fell far short of reaching five million cycles. Dynamic Axial Compression Performance Test. As shown in Table 4, all six samples in the dynamic axial performance test achieved five million cycles under the compressive load range conditions of 343–3428 N, demonstrating sufficient fatigue life. With the increase in the upper and lower limits of the load range, their fatigue life decreased accordingly. Static Torsion Performance Testing. The static torsion testing was conducted using 630 stainless steel as the test pad material, with displacement control loading at a rate of 30 deg/min and an angular displacement offset of 2.3°.

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Number

Maximum loading force (N)

Minimum loading force (N)

Cycles

DJ-2

206

3604

5000000

DJ-3

206

2059

5000000

DJ-1

257

2574

2951608

DJ-4

257

2574

5000000

DJ-5

360

3604

495796

DJ-6

360

3604

207224

Table 4. Dynamic axial compression performance test data of the sample Number

Maximum loading force (N)

Minimum loading force (N)

Cycles

DZ-1

343

3428

5000000

DZ-2

343

3428

5000000

DZ-3

686

6857

3207148

DZ-4

686

6857

1242825

DZ-5

857

8571

1182896

DZ-6

857

8571

1277689

In the test results in Table 5, the average yield torque for the five samples is 41.1 N·m (with a standard deviation of 5.8), and the average yield angle is 26.7 degrees (with a standard deviation of 3.6). Table 5. Static torsion performance test data of the sample Number

Torsional stiffness (N ·m/deg)

Yield torque (N·m)

Yield angle (deg)

Ultimate torque (N·m)

Limiting angle (deg)

JN-1

2.6

48.2

25.3

50.2

29.6

JN-2

3.7

45.9

28.4

47.3

32.2

JN-3

3.0

38.8

28.7

40.4

33.7

JN-4

2.7

38.4

30.2

41.0

34.1

JN-5

3.0

34.3

21.1

37.7

26.9

AVG

3.0

41.1

26.7

43.3

31.1

SD

0.4

5.8

3.6

5.2

3.0

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Static Shear Performance Testing. The static shear performance testing involved evaluating the shear properties of five samples. The testing was conducted by applying a displacement control of 5 mm/min using a 630 stainless steel test block as the loading material. Additionally, a 2% offset was introduced with a horizontal displacement of 0.08 mm. The test results are presented in Table 6, the average displacement corresponding to 2% residual displacement was 1.9 (standard deviation 0.3), and the average shear yield load was 10,112 N (standard deviation 604). These measurements provide insights into the shear behavior and mechanical performance of the samples under static loading conditions. Table 6. Static shear performance test data of samples Number

The displacement corresponding to 2% residual displacement (N ·m/deg)

JJ-1

1.8

JJ-2 JJ-3

Shear yield load (N)

Shear limit displacement (mm)

Shear limit load (N)

9671

2.2

11703

1.6

10017

1.9

11115

1.6

9907

2.3

11910

JJ-4

2.3

9796

2.6

10994

JJ-5

2.1

11167

2.4

12778

AVG

1.9

10112

2.3

11700

SD

0.3

604

0.3

715

Static Axial Compression Performance Testing. In the static axial compression performance testing, the samples were placed on the testing machine with the geometric center of the sample’s spherical interface joint aligned with the loading axis. A 630 stainless steel material was used as the test block. The test data for the five samples are presented in Table 7. The average compression yield load was 34,284 N, and the average compression ultimate load was 37,709 N (standard deviation 1,669).

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Number

Compressive yield load (N)

The displacement corresponding to 2% residual displacement (mm)

Compressive limit load (N)

Compression stiffness (N/mm)

JZ-1

32474

2.8

35013

19065.6

JZ-2

35467

2.9

38070

17301.7

JZ-3

34203

2.5

38016

20361.3

JZ-4

36173

3.2

39614

15974.9

JZ-5

33105

2.5

37831

19940.7

AVG

34284

2.8

37709

18528.8

1552

0.3

1669

1848.5

SD

4 Conclusion An intervertebral fusion implant with a dodecahedral lattice structure was fabricated using Electron Beam Melting (EBM) technology. This porous structure exhibits mechanical properties similar to human bones, reducing the occurrence of stress shielding effects. After undergoing seven types of fatigue tests, it has been demonstrated that this porous intervertebral fusion implant possesses excellent mechanical performance and exhibits effective fatigue life, making it a reliable implant for vertebral reconstruction. Acknowledgement. This study was supported by the Beijing Institute of Graphic Communication R&D Project-Research on Pressure Sensing Antibacterial Polyester Urethral Stent (Ee202207), Innovation projects in incubating technology enterprises-Study on the cell compatibility of new cerebrovascular drug-eluting stent (2021-F-057), Education Reform Project of Beijing Higher Education Association: An Exploration of Teaching Reform centered on the cultivation of Students’ Creative ability under the concept of Universal Printing (MS2022178).

References 1. Cianfoni, A., Massari, F., Ewing, S., Persenaire, M., Rumboldt, Z., Bonaldi, G.: Combining percutaneous pedicular and extrapedicular access for tumor ablation in a thoracic vertebral body. Interv. Neuroradiol. 20(5), 603–608 (2014) 2. Joubert, C., et al.: Corpectomy and vertebral body reconstruction with expandable cage placement and osteosynthesis via the single stage posterior approach: a retrospective series of 34 patients with thoracic and lumbar spine vertebral body tumors. World Neurosurg. 84(5), 1412–1422 (2015) 3. Okazaki, Y., Rao, S., Ito, Y., Tateishi, T.: Corrosion resistance, mechanical properties, corrosion fatigue strength and cytocompatibility of new Ti alloys without Al and V. Biomaterials 19(13), 1197–1215 (1998). https://doi.org/10.1016/s0142-9612(97)00235-4. PMID: 9720903 4. Eisenbarth, E., et al.: Biocompatibility of β-stabilizing elements of titanium alloys. Biomaterials 25(26), 5705–5713 (2004)

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5. Sames, W.J., et al.: The metallurgy and processing science of metal additive manufacturing. Int. Mater. Rev. 61(5), 315–360 (2016) 6. Okazaki, Y., Nishimura, E., Nakada, E., Kobayashi, K.: Surface analysis of Ti–15Zr–4Nb–4Ta alloy after implantation in rat tibia. Biomaterials 22, 599–607 (2001) 7. Heinl, P., Rottmair, A., Körner, C., Singer, R.: Cellular titanium by selective electron beam melting. Adv. Eng. Mater. 9, 360–364 (2007). https://doi.org/10.1002/adem.200700025

Research Progress of 3D Bioprinting PEEK Scaffold Material for Bone Regeneration Wenyu Xie1 , Zongwen Yang1 , Yixin Zhou1 , Xiangqian Xu2 , and Kun Hu1(B) 1 School of Printing and Packaging Engineering, Beijing Institute of Graphic Communication,

Beijing 102600, China [email protected] 2 Huarui (Fujian) Biotechnology CO. Ltd, Fujian 350002, China

Abstract. Polyether ether ketone (PEEK) is a semi-crystalline high-performance polymer, widely recognized on the international stage as one of the most promising next-generation biomaterials poised to replace titanium alloys in the production of bone implants. In contrast to metallic materials, PEEK boasts an elastic modulus similar to that of human bones. It exhibits outstanding biocompatibility, mitigates stress shielding effects, offers X-ray transparency for improved intraoperative and postoperative monitoring, and finds extensive applications across various domains, including spinal, joint, trauma, craniofacial, neurosurgery, and plastic surgery. 3D-printed PEEK composite bone implants exhibit exceptional biocompatibility and possess bone-inductive properties. They can be meticulously designed with porous surface structures conducive to enhanced bone fusion, rendering them highly advantageous for medical applications. This article provides a comprehensive overview of the current research status, manufacturing methodologies, and future prospects of 3D-printed PEEK and its composites in the field of biomedicine. Future research endeavors should aim to further optimize the manufacturing processes and enhance the performance of PEEK implants, ultimately fostering their widespread adoption within the medical community. Keywords: 3D bioprinting technology · PEEK · Bone implant · Tissue engineering

1 Introduction Bone defects refer to situations where the structural integrity of bone is compromised, either due to congenital or acquired factors. Treatment and repair methods for bone defects encompass bone transplantation, gene therapy, and bone tissue engineering. Among these approaches, bone transplantation currently stands as the primary method for addressing bone defects. It includes autologous bone transplantation and allogeneic bone transplantation. Autologous bone is widely regarded as the gold standard for bone fusion, thanks to its exceptional bone-inducing and bone-generating properties [1]. However, autologous bone sources are limited, and the procedure can result in postoperative donor site pain and potential complications. Hence, there is a pressing need to develop an artificial synthetic bone repair material that combines outstanding biocompatibility with robust bone conduction and bone-promoting capabilities. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 136–144, 2024. https://doi.org/10.1007/978-981-99-9955-2_19

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3D-printed PEEK composite bone implants offer excellent biocompatibility and bone-inducing capabilities, along with the capacity to create surface porous structures conducive to bone fusion and growth. Compared to metals, PEEK boasts superior biocompatibility, fatigue resistance, chemical durability, and X-ray transparency, ensuring artifact-free X-ray, CT, and MR scans for enhanced intraoperative and postoperative monitoring. Furthermore, PEEK exhibits exceptional thermal stability and biomechanical properties akin to cortical bone. It excels, especially in irregular bone defects, such as those around the orbit, zygomatic arch, and certain parts of the upper jaw, delivering outstanding aesthetic results as an implant material. Personalized PEEK bone implants can be crafted using 3D printing techniques like fused filament fabrication (FFF) and fused deposition modeling (FDM) to design innovative porous scaffold structures that facilitate bone conduction. However, pure PEEK material is inert and exhibits weak osteogenic activity, limiting its ability to establish a robust and reliable connection with bone tissue. This restriction hampers the long-term stability and clinical utility of PEEK bone substitutes. Consequently, PEEK-based composite materials are widely employed to enhance PEEK’s biological activity, osteogenic potential, and bone integration capability. This is accomplished by blending PEEK with bio-ceramics like bioactive glass (BGA), tricalcium phosphate (TCP), hydroxyapatite (HA), as well as incorporating various bioactive factors, materials, nanoparticles, and advanced 3D printing techniques. This article provides an overview of the diverse applications of 3D-printed PEEK in bone repair and associated modifications (Fig. 1).

Fig. 1. Current status of the development of PEEK bone implants

2 3D Bioprinting Properties of PEKK When PEEK material is employed in the realm of 3D printing, it offers a remarkable advantage: the ability to fabricate complex geometric shapes that prove challenging for many other materials. PEEK’s low moisture absorption makes it well-suited for 3D printing techniques such as fused deposition modeling (FDM) or fused filament

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fabrication (FFF). The optimal printing conditions typically involve nozzle temperatures between 360–400 °C and a heated bed temperature of 120 °C. PEEK is inherently a robust 3D printing polymer, holding significant promise, particularly in the medical field, owing to its exceptional biocompatibility. In the realm of biomedicine, PEEK’s outstanding biocompatibility, coupled with an elastic modulus closely mirroring that of human bone, positions it as an ideal material for orthopedic implants when compared to metallic counterparts. Recent research demonstrates that PEEK implants not only offer sufficient load-bearing strength but also exhibit relatively lightweight properties. They can be engineered as porous implants to facilitate enhanced cell regeneration. The application of high-temperature, implantable polymer PEEK opens the door to a more advanced generation of biomaterials. Implementing FDM/FFF 3D printing in the medical context reduces material wastage, expedites implant production, enhances costeffectiveness, and enables tailored treatments for individual patients. PEEK’s impressive role in the medical field aligns with the increasing prevalence of 3D printing technology, particularly in sectors such as aerospace and healthcare. Precision medicine, in particular, relies on the integration of 3D printing capabilities.

3 Modification of 3D Bioprinted PEEK 3.1 Bioactive PEEK Composite Implants As a novel polymer material, pure PEEK often struggles to meet the diverse demands of applications within complex bone environments. However, PEEK can serve as a substrate, and its properties can be optimized through the addition of various fillers. There are several methods for preparing PEEK composites [2], broadly categorized into two main types: physical blending and chemical synthesis. Physical blending involves mixing two distinct materials together, often using methods like ball milling. However, these techniques can significantly reduce the tensile strength of the material, and issues with delamination between PEEK and inorganic materials can be quite pronounced. Chemical synthesis, particularly in-situ polymerization [2], is an emerging technique for creating PEEK composites. Researchers typically leverage nucleophilic reactions of PEEK as the foundational process. In this method, inorganic fillers are introduced while PEEK is in its prepolymer state, ensuring even dispersion of the inorganic fillers within the PEEK prepolymer. The mixture is then polymerized to yield PEEK-based composite materials. This approach results in well-dispersed composite materials with a strong bond between the matrix material and inorganic fillers. It holds significant promise for addressing interface bonding issues between PEEK and inorganic fillers. Zheng et al. [3] utilized the fused filament fabrication (FFF) technique to create PEEK/HA scaffolds with varying levels of hydroxyapatite (HA) content, including samples with 0%wt, 20%wt, and 40%wt HA. Through cell experiments, micro-CT imaging (as shown in Fig. 2), and staining observations, their research revealed that the introduction of HA significantly enhances the biocompatibility and surface roughness of PEEK/HA scaffolds. This, in turn, promotes inward bone growth, improving the scaffold’s ability to bond with and integrate into natural bone. Moreover, mesenchymal stem

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cells exhibited notably enhanced adhesion, proliferation, osteogenic differentiation, and mineralization capabilities when cultured on PEEK/HA scaffolds.

Fig. 2. Geometry observation from Micro-CT of the PEEK/HA scaffold samples

3.2 PEEK Surface Modification Surface modification methods can effectively enhance the biocompatibility of PEEK materials while improving their antimicrobial and bone integration properties [3]. These methods are generally categorized into three main classes: physical modification, chemical modification, and coating modification, as outlined in Table 1. Active metal ions can regulate cell functions and track biological behaviors by mediating signal transduction pathways. Moreover, the release of active metal ions from different biomaterials is crucial for promoting specific functions. Experiments have shown that the release of biologically active ions (such as magnesium, strontium, manganese, zinc, silver, and copper) can enhance bone integration, vascularization, tissue regeneration, and antimicrobial properties, thus improving human health and quality of life. Manganese, as an essential trace element in the human body, serves various biological functions. For example, manganese is involved in the bone formation process and antioxidant defense mechanisms. It is also a necessary cofactor for metal enzymes, DNA polymerases, and kinases. Research has shown that manganese affects human osteoblast integrin activity, mediates interactions with the extracellular matrix (ECM), and promotes cell adhesion, spreading, and proliferation. Additionally, Mn2+ ions play a crucial role in the synthesis of structural proteins like collagen in bone and connective tissue formation. On the other hand, silver ions can inhibit bacterial infections and have inhibitory effects on both gram-positive and gram-negative bacteria. Silver-doped coatings exhibit excellent biocompatibility and are only toxic to mammalian cells at high concentrations. Yang et al. [4] have proposed a simple immersion method to prepare dual-functional polyether with antimicrobial and enhanced bone integration properties, as shown in Fig. 3. They modified the PEEK surface by incubating it in a dopamine solution to create a polydopamine (PDA) coating. Then, PEEK-PDA was further modified with manganese (Mn) and silver (Ag) ions through immersion to produce PEEK-PDA-Mn/Ag.

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Physical modification

Plasma treatment Physical vapor deposition

Chemical modification

Sulfonated modification Surface grafting Loaded growth factor

Coating modification

Graphene Oxide (GO) coating Hydroxyapatite (HA) coating Polydopamine (PDA) bionic coating Surface deposition technique

The physical and chemical properties of PEEK-PDA-Mn/Ag, including ion release, wettability, morphology, and elemental distribution, were investigated. PEEK-PDA-Mn/Ag significantly enhanced the adhesion and spreading of mouse embryonic osteoblasts (MC3T3-E1 cells) and exhibited good in vitro biocompatibility. Furthermore, PEEKPDA-Mn/Ag demonstrated osteogenic characteristics by upregulating osteogenic gene expression, alkaline phosphatase (ALP) activity, and mineralization, thereby promoting bone integration. Additionally, PEEK-PDA-Mn/Ag exhibited antimicrobial properties both in vitro and in vivo. In conclusion, the simple immersion method can modify the surface of polyether ether ketone, imparting it with bioactivity, biocompatibility, and antimicrobial capabilities, making it suitable for clinical applications in orthopedic implants.

Fig. 3. Illustration of surface modification of PEEK and the evaluation of its properties in vitro and in vivo

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4 Clinical Application of PEEK Scaffold for Bone Repair In recent years, PEEK has gained widespread acceptance and application across a spectrum of clinical settings, including spinal surgery, joint replacements, trauma treatment, maxillofacial surgery, neurosurgery, and plastic surgery, as shown in Fig. 4. Its versatility extends to various procedures such as fracture fixation, craniofacial defect repairs, spinal implants, total joint arthroplasty (TJA), and even as suture anchors for soft tissue repairs. Within the field of dentistry, PEEK’s utility is expansive, encompassing dental implants, abutment rods, dentures, abutments, and fixtures. In the following sections, I will provide specific details about various 3D-printed PEEK orthopedic implants employed in the treatment of orthopedic conditions.

Fig. 4. Related applications of PEEK implants

4.1 Fracture Repair The use of metal sheets for internal fracture fixation dates back to 1895, but corrosion and stress shielding issues posed challenges. Stainless steel addressed corrosion but brought concerns about stress shielding, potentially leading to re-fractures when plates were removed. PEEK, with superior fatigue strength and good histocompatibility, overcomes these limitations. It ensures a precise fit to bone tissue, reducing the risk of re-fracture. Chen et al. [5] demonstrated 3D-printed PEEK implants for clavicle reconstruction after chronic osteomyelitis removal, as shown in Fig. 5. A 23-year-old patient experienced successful two-year follow-up with no implant issues. This highlights 3D-printed PEEK’s effectiveness in such reconstructions. 4.2 Heart Pumps and Valves An aging population has led to an increased prevalence of cardiovascular diseases, making them the leading cause of death among the elderly. In their study, Yusuke et al.

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a. X-ray films at first admission b.X-ray films after spacer implanted admission d.CT films after spacer implanted.

c. CT films at first

Fig. 5. No failure or loosening of implant:

[6] explored the effectiveness of a bileaflet valve crafted from poly(ether ether ketone) (PEEK) with a surface grafted with poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) (PEEK-g-PMPC), as shown in Fig. 6. The goal was to enhance thrombotic resistance in mechanical heart valves, thus reducing the risk of thromboembolism and thrombosis, and allowing for a reduction in anticoagulant doses, such as warfarin. In stark contrast to untreated PEEK valves, a gross anatomical examination revealed no thrombus formation on the PEEK-g-PMPC valve. Moreover, there were no mobile thrombi observed in kidney and lung tissues. These findings suggest that PEEK-g-PMPC is a thromboresistant material with outstanding mechanical properties.

a. Photographs of a PEEK-g-PMPC valve ring and leaflets b.Photograph of a PEEK-g-PMPC valve with an ePTFE sewing cuff Fig. 6. A custom-made filament (diameter, 0.2 mm) and 12-mm bileaf-let valve made of PEEK

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5 Conclusion Biological 3D printing of PEEK material has promising applications in addressing clinical challenges related to large bone defects and bone fusion surgeries. PEEK, known for its favorable mechanical properties in the biomedical field, has increasingly replaced titanium and ceramic implants for various bone defect repairs. To further improve PEEK’s bone-inducing and antibacterial capabilities, surface functionalization and structural modifications are essential. The synthesis of PEEK composites enhances its biological and mechanical properties. With the advancement of 3D printing technology and growing patient demands for personalized bone repair treatments, customized PEEK implants tailored to individual patients offer excellent mechanical properties, biocompatibility, and bioactivity. These implants have shown remarkable efficacy in repairing defects in the oral cavity, artificial bone joints, jawbones, and skulls, resulting in high patient satisfaction. Personalized stents simplify procedures, reduce operation times, and hold great promise for the future. Current bio-3D printing of PEEK scaffolds faces several key challenges: (1) The success of personalized PEEK implants relies heavily on the capabilities of 3D printing systems. Developing dedicated 3D printers for PEEK and reducing material and machine costs are essential to drive the adoption of PEEK-based medical applications. (2) Research is needed to investigate the impact of modification techniques like composites, coatings, and growth factor incorporation on 3D printed PEEK scaffold performance. Enhancing implant performance is a crucial area of exploration. (3) Addressing issues related to directional cell differentiation, new bone growth within the scaffold, and achieving an appropriate three-dimensional micro-nano porous structure for improved biocompatibility remains a challenge. Currently, clinical applications of PEEK encounter post-processing challenges and precision limitations in 3D printing, leading to potential complications and adverse reactions in patients after surgery. However, ongoing research in biological 3D printing of medical-grade PEEK and its composites is progressively identifying and overcoming these issues. This technology holds the promise of becoming a personalized and precise medical solution, with extensive applications in orthopedic clinical medicine to effectively address bone repair treatments. Acknowledgement. This study was supported by the Beijing Institute of Graphic Communication R&D Project-Research on Pressure Sensing Antibacterial Polyester Urethral Stent (Ee202207), Innovation projects in incubating technology enterprises-Study on the cell compatibility of new cerebrovascular drug-eluting stent (2021-F-057), Education Reform Project of Beijing Higher Education Association: An Exploration of Teaching Reform centered on the cultivation of Students’ Creative ability under the concept of Universal Printing (MS2022178).

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References 1. Wang, Z., Wang, Y., Yan, J., et al.: Pharmaceutical electrospinning and 3D printing scaffold design for bone regeneration. Adv. Drug Deliv. Rev. 174, 504–534 (2021) 2. Ma, J., Tang, B.: Application of polyetheretherketone in the orthopedic implants. Progr. Chem. 30(11), 1692–1700 (2018) 3. Zheng, J., Zhao, H., Ouyang, Z., et al.: Additively-manufactured PEEK/HA porous scaffolds with excellent osteogenesis for bone tissue repairing. Compos. B Eng. 232, 109508 (2022) 4. Yang, X., Wang, Q., Zhang, Y., et al.: A dual-functional PEEK implant coating for anti-bacterial and accelerated osseointegration. Colloids Surf. B 224, 113196 (2023) 5. Chen, C., Yin, Y., Xu, H., et al.: Personalized three-dimensional printed polyether-ether-ketone prosthesis for reconstruction after subtotal removal of chronic clavicle osteomyelitis: a case report. Medicine 100(17) (2021) 6. Kambe, Y., Mahara, A., Tanaka, H., et al.: Short-term evaluation of thromboresistance of a poly (ether ether ketone)(PEEK) mechanical heart valve with poly (2-methacryloyloxyethyl phosphorylcholine)(PMPC)-grafted surface in a porcine aortic valve replacement model. J. Biomed. Mater. Res., Part A 107(5), 1052–1063 (2019)

Research Progress of 3D Printed Microneedle Blood Glucose Sensor Yixin Zhou1 , Kun Hu1(B) , Ya Zhu2(B) , and Xiangqian Xu3 1 School of Printing and Packaging Engineering, Beijing Institute of Graphic Communication,

Beijing 12600, China [email protected] 2 Beijing SinotechWellcare Technology Development Co. Ltd., Beijing 100195, China [email protected] 3 Huarui (Fujian) Biotechnology Co. Ltd., Fujian 350002, China

Abstract. Diabetes mellitus is a common chronic metabolic disease caused by insulin secretion deficiency or insulin dysfunction, with multiple clinical manifestations and serious complications, and is one of the main causes of death. Continuous blood glucose monitoring can obtain human blood glucose information in real time and more directly understand human blood glucose fluctuations, so as to detect and treat latent symptoms of high/low blood glucose as early as possible. With the development of 3D printing technology in the field of medical devices, biosensors have enormous potential in continuous diabetes monitoring. This article primarily investigates the recent advancements in glucose micro-needle sensors fabricated using 3D printing technology for blood glucose monitoring. It evaluates the performance differences resulting from various fabrication methods, thus elucidating the current status and future research directions in continuous diabetes monitoring. This facilitates also help bridge the gap between laboratory research and clinical care point in the future. Keywords: 3D printing technology · Microneedle · Sensor

1 Introduction Diabetes is a systemic disease with potentially life-threatening consequences [1] that affect hundreds of millions of people worldwide. It is projected that by 2030, the total number of individuals affected will rise to 643 million, and by 2045, it will increase to 783 million [2].The measurement of blood glucose levels (BGL) is regarded as the clinical gold standard for the diagnosis and management of diabetes. Traditionally, blood glucose monitoring has involved patients performing fingerstick tests multiple times a day. While highly accurate in detecting blood glucose levels, fingerstick testing is painful and inconvenient. Thus, irregular measurements have limited the applicability of fingerstick tests and disrupted the management of diabetes [3]. Continuous glucose monitoring (CGM) is a concept developed in the 1960s to measure glucose levels in interstitial fluid (ISF). It has been demonstrated to significantly improve the quality of diabetes treatment, providing continuous real-time measurements and a comprehensive © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 145–152, 2024. https://doi.org/10.1007/978-981-99-9955-2_20

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temporal overview [4]. Wearable gadgets with real-time continuous glucose monitoring capabilities are currently available on the market [5]. These devices extract glucose from ISF through the skin using low current, minimizing pain and invasiveness, making them highly popular among diabetes patients. Transdermal Drug Delivery (TDD) aims to overcome the limitations of traditional drug administration routes. However, the widespread application of TDD has been hindered due to the inherent characteristics of the skin barrier, especially the limitations imposed by the stratum corneum. Figure 1 depicts the internal structure of human skin and its different layers [6]. Skin tissue consists of three layers: the epidermis, dermis, and subcutaneous tissue (Fig. 1B). The epidermis consists of multiple layers of epithelial cell sheets with a thickness of 100–200 µm. The dermis is a dense connective tissue containing blood vessels, nerves, hair follicles, sebaceous glands, and sweat glands [7]. The subcutaneous layer is located beneath the dermis and is composed of loose fat [8] and connective tissue. Microneedle arrays (MNAs) are small devices capable of penetrating the outermost layer of human skin, successfully delivering active substances such as drugs, ribonucleic acid (RNA), deoxyribonucleic acid (DNA), and vaccines directly into the skin microcirculation. Due to their small size, they keep the skin nerves intact upon insertion, and the drugs do not pass through any metabolic systems, thus enhancing bioavailability.

a. Skin tissue consists of three layers: epidermis, dermis and subcutaneous tissue b. Outermost layer, the epidermis, is a keratinized lamellar squamous epithelium with closely packed epithelial cells. Fig. 1. Internal structure of the human body and skin tissue structure [6]

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2 Microneedle System A microneedle system is a type of small needle-like structure used for drug delivery, biosensing, tissue sampling, and other biomedical applications. These microneedles are typically composed of tiny needle tips or needle-like structures that can penetrate the skin or other biological tissues. They are usually very small, with diameters ranging from a few hundred micrometers to a few millimeters, and lengths typically less than a few millimeters. This makes microneedle delivery relatively painless and suitable for various drug delivery and biosensing tasks. 2.1 Manufacturing Method of Microneedles Traditional needles are typically made of stainless steel, whereas MNAs can be fabricated from various alternative materials, such as polymers and inorganic materials, and come in various geometrical shapes, different heights, diameters, and needle designs. However, in these investigations, microneedles are entirely manufactured using a template-based fabrication approach, which involves the design and creation of master templates, casting of microneedles using the master template, and post-curing and stripping [9]. Due to the complexity of the template-based fabrication approach, an alternative method for manufacturing microneedle systems has been proposed. 3D printing is an additive manufacturing process [10] that transforms 3D computeraided design (CAD) models into physical objects layer by layer, creating structures, prototypes, and architectures. Currently, stereo lithography appearance (SLA), digital light processing (DLP), two-photon or multi-photon polymerization (2PP or MPP), fused deposition modeling (FDM), selective laser sintering (SLS), and selective laser melting (SLM) are employed as 3D printing techniques in the manufacture of microneedles. These methods are generally easily accessible, enable rapid prototyping, and allow for the integration of cell encapsulation structures with bioinks for the manufacture of advanced healthcare devices. As shown in Fig. 2 below [11], this enables personalized treatment choices and point-of-care (POC) diagnostics, meaning testing can be performed at or near the clinical point of patient care. Experimental reports have identified factors influencing 3D-printed microneedles in fluid sampling or extraction processes [12], such as ISF, blood, and glucose detection, as shown in Fig. 3.Two key parameters are printing resolution and material properties. Factors affecting printing resolution include printing angle, layer height, printing speed, printing temperature, print plane, orientation angle, and fill pattern, among others [13]. The height of MNAs typically ranges from 400 to 800 µm [14]. Razzaghi et al. studied the influence of printing angle on the penetration force of MNAs and found that penetration force decreased with increasing printing angle but increased with increasing needle tip angle [15]. It was also observed that the best quality of printed microneedles was obtained at a 45° angle compared to horizontal printing platforms [16]. Chua et al. investigated the impact of microneedle shapes on skin penetration and found two possible ways in which microneedle shapes affect the performance of CGM systems: (i) penetration and (ii) occlusion of the lumen by displaced skin material. In this regard, conical silicon microneedle arrays were found to be more advantageous

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than linear silicon microneedle arrays [17]. Regarding printing materials, it is necessary for the materials to possess attributes such as biocompatibility, good mechanical strength, sterilizability, and biodegradability. Therefore, careful consideration of material selection is crucial, especially in strict regulatory environments, to provide patients with innovative, safe, and effective microneedle devices.

Fig. 2. Integration of microneedle arrays (MNAs) with Point of Care (POC) biosensor technology for monitoring different particles (biomarkers and ions) and disease diagnosis (cancer and allergy) [11]

Fig. 3. Factors affecting the development of microneedles [12]

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2.2 3D Printed Microneedles Applied to Blood Sugar Management In a study conducted by Cristiane et al., SLA was used as the printing technology to prepare insulin-loaded MNAs with trehalose, mannitol, and xylitol as drug carrier coatings [18]. In vitro insulin studies on pigskin revealed an increase in insulin release over time, with 90%–95% of insulin detected within 30 min after insertion into the skin. This demonstrated that 3D printing is an effective technology for manufacturing biocompatible and scalable microneedle patches. Glucose oxidase is an enzyme that, with the help of oxygen, converts glucose into gluconic acid [19]. In cases of hypoxia or elevated glucose levels, lipophilic 2-nitroimidazole is converted to hydrophilic 2-aminimidazole, leading to the dissolution of hyaluronic acid vesicles and insulin release. Therefore, glucose oxidase is used in combination with insulin in microneedle formulations, serving as a biosensor and enabling insulin release under hypoxic conditions [20]. Wu et al. utilized various bioinks composed of alginate and hydroxyapatite and employed extrusion-based 3D printing followed by post-stretching to create sharpened needle tips, also manufacturing MNAs coated with insulin. When applied transdermally only once on mouse skin, the microneedle patch regulated blood glucose levels in diabetic mice within the normal range for up to 40 h and alleviated diabetes symptoms in the mice [21]. Economidou et al. used SLA printing technology to manufacture MN arrays by polymerizing consecutive Dental SG layers and then coated the surface of these MN arrays with insulin and carriers such as xylitol, mannitol, and trehalose using piezoelectric inkjet printing technology [22]. The study found that these insulin-coated pyramid-shaped MNAs applied minimal force (2-5N) to penetrate the skin. Furthermore, in in vivo testing on a diabetic mouse model, insulin controlled blood glucose levels within 60 min and maintained stable blood glucose levels within 4 h. Gittard et al. developed solid MNAs containing insulin using two-photon polymerization and PDMS micro-molding technology. The results showed that a 5 × 5 microneedle array could withstand axial loads of up to 10 N without fracturing, equivalent to an axial load of 0.4 N per needle, demonstrating the mechanical properties required for transdermal insulin delivery [23]. Ross et al. coated insulin on metal MNAs with SOL and trehalose films using piezoelectric inkjet printing technology. Permeation studies on pigskin indicated rapid insulin release within the first 20 min, with the complete release of its active units after 40 min, suggesting solid-state delivery of insulin through insulin-coated solid MNAs [24]. Iakovos et al. successfully applied hollow hydrogel microneedles printed from Dental SG using the liquid crystal display (LCD) cylinder-aggregation method for insulin delivery [25]. Fang et al. manufactured 3D printed microneedles with open groove channels. These groove microneedles demonstrated high efficiency in fluid extraction, requiring only 3 s to extract fluid from a solution [26]. Each 3 × 4 microneedle array could extract 20– 30 µl of fluid within 15 s without additional absorbent materials. Glucose test strips were integrated into the device for analyzing glucose concentrations in a gelatin hydrogel skin model. It was found that fluid extraction took only 30 s, and the device’s measurements were consistent with test strip results, showing promising applications. However, these devices were based on fixed drug-loaded and coated microneedle arrays and could not offer personalized therapeutic delivery.

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Subsequently, Economidou et al. combined stereolithography and SLA technology to print hollow microneedle arrays, which were then integrated into a microelectromechanical system (MEMS). Experimental results showed that MNAs had an insertion force of approximately 1.62N with minimal pain [27]. A small amount of insulin (0.5IU) led to a rapid decrease in blood glucose levels within 1 h. This device overcame the limitation of fixed drug-loaded microneedles but faced issues with clogging during skin insertion [28]. Liu et al. printed [29] conical microneedle arrays on a substrate using DLP and then deposited Au/Prussian Blue mediator/GOX sequentially onto the working electrode using magnetron sputtering. Testing in goat plasma with glucose concentrations ranging from 3 to 40 mM revealed that the sensor accurately detected glucose within a linear concentration range of 3–24 mM, with a linear slope of 0.1216 ± 0.0044 µA/mM and a detection limit of 48.1 µM. The detection limit for glucose sensors in simulated ISF was 8.65 µM. These results suggest that integrated microneedle biosensing devices can be used for precise and continuous monitoring of subcutaneous glucose. However, there are currently no commercial products available in this field.

3 Conclusion This review article extensively discusses the benefits of continuous blood glucose monitoring and the advantages, influencing factors, and applications of microneedle systems in blood glucose management. The unique capabilities of 3D printing technology have made simple and rapid customization a powerful asset, reducing production timelines and simplifying business models. However, further research is still needed to develop and clinically evaluate an accurate, safe, user-friendly, and cost-effective minimally invasive microneedle continuous blood glucose monitoring system. Additionally, the integration of microneedle array technology for therapeutic and diagnostic purposes opens up new possibilities for closed-loop insulin delivery and blood glucose monitoring for diabetes patients. It is anticipated that in the near future, the drug-loading capacity of microneedles and the repeatability of drug sustained release will significantly improve. These advancements are expected to enhance diabetes management and provide better treatment and monitoring options, potentially positively impacting the quality of life for diabetes patients. Acknowledgement. This study was supported by the Beijing Institute of Graphic Communication R&D Project-Research on Pressure Sensing Antibacterial Polyester Urethral Stent (Ee202207), Innovation projects in incubating technology enterprises-Study on the cell compatibility of new cerebrovascular drug-eluting stent (2021-F-057), Education Reform Project of Beijing Higher Education Association: An Exploration of Teaching Reform centered on the cultivation of Students’ Creative ability under the concept of Universal Printing (MS2022178).

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References 1. Gao, J., Huang, W., Chen, Z.: Simultaneous detection of glucose, uric acid and cholesterol using flexible microneedle electrode array-based biosensor and multi-channel portable electrochemical analyzer. Sens. Actuators B Chem. 287, 102–110 (2019) 2. Zhu, X., Ju, Y., Chen, J.: Nonenzymatic wearable sensor for electrochemical analysis of perspiration glucose. ACS Sens. Am. Chem. Soc. 3(6), 1135–1141 (2018) 3. Cheng, Y., Gong, X., Yang, J.: A touch-actuated glucose sensor fully integrated with microneedle array and reverse iontophoresis for diabetes monitoring. Biosens. Bioelectron. 203, 114026 (2022) 4. Lau, J.L., Dunn, M.K.: Therapeutic peptides: historical perspectives, current development trends, and future directions. Bioorg. Med. Chem. 26(10), 2700–2707 (2018) 5. American Diabetes Association: 2. classification and diagnosis of diabetes: standards of medical care in diabetes-2021. Diabetes Care 44(Suppl 1), S15–S33 (2021) 6. Dabbagh, S.R., Sarabi, M.R., Rahbarghazi, R.: 3D-printed microneedles in biomedical applications. iScience 24(1), 102012 (2021) 7. Russell, L.M., Wiedersberg, S., Delgado-Charro, M.B.: The determination of stratum corneum thickness: an alternative approach. Eur. J. Pharmaceut. Biopharmaceut. Off. J. Arbeitsgemeinschaft Fur Pharmazeutische Verfahrenstechnik e.V 69(3), 861–870 (2008) 8. Wang, J., et al.: Synergistic effect of well-defined dual sites boosting the oxygen reduction reaction. Energy Environ. Sci. 11(12) (2018) 9. Jicheng, Y., Yuqi, Z., Yanqi, Y.: Microneedle-array patches loaded with hypoxia-sensitive vesicles for rapid glucose-responsive insulin delivery. Front. Bioeng. Biotechnol. 4 (2016) 10. Bose, S., Ke, D., Sahasrabudhe, H.: Additive manufacturing of biomaterials. Prog. Mater. Sci. 93, 45–111 (2018) 11. Rezapour Sarabi, M., Nakhjavani, S.A., Tasoglu, S.: 3D-printed microneedles for point-ofcare biosensing applications. Micromachines 13(7), 1099 (2022) 12. Avcil, M., Çelik, A.: Microneedles in drug delivery: progress and challenges. Micromachines 12(11), 1321 (2021) 13. Economidou, S.N., Douroumis, D.: 3D printing as a transformative tool for microneedle systems: recent advances, manufacturing considerations and market potential. Adv. Drug Deliv. Rev. 173, 60–69 (2021) 14. Eunju, K., et al.: Solvent-responsive polymernanocapsules with controlled permeability: encapsulation and release of a fluorescent dye by swelling and deswelling. Chem. Commun. 28(12), 1472–1474 (2009) 15. Razzaghi, M., Akbari, M.: The effect of 3D printing tilt angle on the penetration of 3D-printed microneedle arrays. Micromachines 14(6), 1157 (2023) 16. Economidou, S., Pissinato Pere, C., Okereke, M.: Optimisation of design and manufacturing parameters of 3D printed solid microneedles for improved strength, sharpness, and drug delivery. Micromachines 12(2), 117 (2021) 17. Chua, B., Desai, S.P., Tierney, M.J.: Effect of microneedles shape on skin penetration and minimally invasive continuous glucose monitoring in vivo. Sens. Actuators A 203, 373–381 (2013) 18. Pere, C.P.P., et al.: 3D printed microneedles for insulin skin delivery. Int. J. Pharmaceut. 544(2) (2018) 19. Chang, H., Zheng, M., Yu, X.: A swellable microneedle patch to rapidly extract skin interstitial fluid for timely metabolic analysis. Adv. Mater. 29(37), 1702243 (2017) 20. Danne, T., Heinemann, L., Bolinder, J.: New insulins, biosimilars, and insulin therapy. Diabetes Technol. Ther. 23(S2), 46–68 (2021)

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21. Wu, M., Zhang, Y., Huang, H.: Assisted 3D printing of microneedle patches for minimally invasive glucose control in diabetes. Mater. Sci. Eng. C 117, 111299 (2020) 22. Economidou, S.N., Pere, C.P.P., Reid, A.: 3D printed microneedle patches using stereolithography (SLA) for intradermal insulin delivery. Mater. Sci. Eng. C 102, 743–755 (2019) 23. Gittard, S.D., Ovsianikov, A., Monteiro-Riviere, N.A.: Fabrication of polymer microneedles using a two-photon polymerization and micromolding process. J. Diabetes Sci. Technol. 3(2), 304–311 (2009) 24. Ross, S., Scoutaris, N., Lamprou, D., Mallinson, D., Douroumis, D.: Inkjet printing of insulin microneedles for transdermal delivery. Drug Deliv. Transl. Res. 5, 451–461 (2015) 25. Xenikakis, I., Tsongas, K., Tzimtzimis, E.: Additive manufacturing of hollow microneedles for insulin delivery. Int. J. Mod. Manuf. Technol. 13, 185–190 (2021) 26. Leng, F., Zheng, M., Xu, C.: 3D-printed microneedles with open groove channels for liquid extraction. Exploration 1(3), 20210109 (2021) 27. Economidou, S.N., Uddin, M., Marques, M.J.: A novel 3D printed hollow microneedle microelectromechanical system for controlled, personalized transdermal drug delivery. Addit. Manuf. 38, 101815 (2021) 28. Cárcamo-Martínez, Á., Mallon, B., Domínguez-Robles, J.: Hollow microneedles: a perspective in biomedical applications. Int. J. Pharm. 599, 120455 (2021) 29. Liu, Y., Yu, Q., Luo, X.: Continuous monitoring of diabetes with an integrated microneedle biosensing device through 3D printing. Microsyst. Nanoeng. 7(1), 75 (2021)

Surface and Interface Modified Cellulose Nanofibers for Direct Writing and Printing Triboelectric Nanogenerator Xiaofei Fu1 , Xiaofei Wu1 , and Zhengjian Zhang1,2(B) 1 College of Light Industry Science and Engineering, Tianjin University of Science

and Technology, Tianjin 300457, China [email protected] 2 State Key Laboratory of Biobased Fiber Manufacturing Technology, Tianjin University of Science and Technology, Tianjin 300457, China

Abstract. In recent years, cellulose has garnered significant attention in the preparation of triboelectric nanogenerators due to its excellent biodegradability and reproducibility. However, the weak surface polarity and insufficient surface functional groups have considerably constrained its progress towards achieving highperformance TENG. Here, nanocellulose (CNFs) was employed as the friction layer material for the triboelectric nanogenerator. The surface interface was modified through chemical treatment, introducing two functional groups, -NH2 and -F. Besides analyzing the electron gain and loss capabilities and polarity of two distinct functional celluloses, functionalized CNFs were also employed in a directwriting approach to fabricate three-dimensional structures for TENG applications. Furthermore, CNFs with enhanced surface and interface can also enhance the electrical output performance of triboelectric nanogenerators. The results indicated that when the mass ratio of epoxy propyl trialkylamine chloride (EPTMAC) to cellulose was 2.0, the cationic degree was at its highest. The introduction of -F, achieved by using nano SiO2 and PFOTS, not only rendered the water contact angle of FCNF-SiO2 aerogel superhydrophobic at 150° but also yielded the maximum output voltage when the mass ratio of dried fiber to nano SiO2 was 3.0. These results further demonstrate the irreplaceable advantages and practical application potential of CNFs in the environmentally friendly mechanical energy collection system, specifically in triboelectric nanogenerators. Keywords: Triboelectric nanogenerator · Nanocellulose · Surface modification · Direct ink writing

1 Introduction TENG offers numerous advantages, including low cost, structural diversity [1–3], stable power output [4, 5], high energy conversion efficiency [6], shape flexibility [7], and environmental friendliness [4, 8, 9]. However, traditional methods for preparing composite triboelectric nanogenerators (TENG) do not fully align with the principles of green © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 153–161, 2024. https://doi.org/10.1007/978-981-99-9955-2_21

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environmental protection. Therefore, the selection of high-quality TENG friction layer materials from nature, such as nanocellulose, starch, diatom shell [4], and lignin [5], presents a new development opportunity for future environmentally friendly, bio-based TENG technology. Cellulose Nanofiber (CNF) consists of linear 1,4-linked D-glucose units and features abundant hydroxyl (-OH) active groups, which can form intermolecular and intramolecular bonds between polymer chains, thus creating a robust hydrogen bonding network [10, 11]. Incorporating cellulose into the field of TENG not only enables efficient environmental energy harvesting but also ensures the environmentally friendly and sustainable application of TENG materials [12]. In this study, we utilized 2,3-epoxypropyltrimethylammonium chloride (EPTMAC) to cationize cellulose fibers and performed cellulose fluorosilication to modify the surface and interface of cellulose. We employed direct ink writing (DIW) to fabricate TENG friction layer devices with three-dimensional structures. The results indicated that when the mass ratio of EPTMAC to cellulose was 2.0, the cationic degree reached its peak. The introduction of -F, achieved by employing nano SiO2 and 1H, 1H, 2H, 2H-perfluorodecyl trichlorosilane (PFOTS), not only rendered the water contact angle of FCNF-SiO2 aerogel superhydrophobic at 150° but also yielded the maximum output voltage when the mass ratio of dried fiber to nano SiO2 was 3.0. These findings further underscore the irreplaceable advantages and practical application potential of CNFs in the new environmentally friendly mechanical energy collection system, specifically TENG.

2 Experiments 2.1 Main Materials and Equipment The experimental equipment and materials for this article are shown in Table 1 and Table 2. Table 1. Main materials Name

Specifications

Manufacturer

Eucalyptus bleached kraft pulp board

chemical pulp

Jiangsu Fenou Huichuan Paper Industry Co., Ltd

Sodium bromide

analytical pure

Beijing Huaxia Ocean Technology Co., Ltd

Sodium hypochlorite

analytical pure

Tianjin Yuanli Chemical Co., Ltd

Sodium hydroxide

analytical pure

Tianjin Jiangtian Chemical Technology Co., Ltd

2,2,6,6-tetramethylpiperidine oxide (TEMPO)

analytical pure

Beijing Huaxia Fish Ocean Technology Co., Ltd

Hydrochloric acid

analytical pure

Tianjin Jiangtian Chemical Technology Co., Ltd (continued)

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Table 1. (continued) Name

Specifications

Manufacturer

Anhydrous ethanol

analytical pure

Tianjin Jiangtian Chemical Technology Co., Ltd

Carboxymethyl cellulose sodium

analytical pure

Shandong Xiya Chemical Industry Co., Ltd

Ethyl orthosilicate

chemically pure

Tianjin Zhiyuan Chemical Reagent Co., Ltd

Methyl cellulose

chemically pure

Shandong Xiya Chemical Industry Co., Ltd

Polyvinyl alcohol (PVA)

analytical pure

Source leaf organism

Silica

analytical pure

Tianjin Tianying Fine Chemical Co., Ltd

Liquid nitrogen

/

Tianjin Changfu Gas Co., Ltd

Table 2. Main equipment Name

Specifications

Manufacturer

Mixer

S312900

Shanghai Shensheng Biotechnology Co., Ltd

Circulating water vacuum pump

SHB-III

Changsha Mingjie Instrument Co., Ltd

pH meter

STARTER 3C

Aarhus Instruments Co., Ltd

High Pressure Homogenizer

H1650

Hunan Xiangyi Experimental Instrument Co., Ltd

Direct writing printer

E2V

Nordson EFD

Freeze dryer

Alpha1-2Ldplus

CHRIST Lyophilizer GmbH, Germany

Deflaker

T-100

ADIRONDACK MACHINR CORPORATION

Rheometer

MCR 302

Anton Paar

Dynamic contact angle tester

JY-82A

Chengde Dingsheng Testing Machine Testing Equipment Co., Ltd

Field emission scanning electron microscope

TESCAN MIRA

Japanese Electronics Company (continued)

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Name

Specifications

Manufacturer

Energy dispersion spectrometer (EDS)

JED-2300

Japanese Electronics Company

XPS

Thermo Scientific K-Alpha

Thermo Fisher Scientific, USA

FTIR

Nicolet iS5

Thermo Fisher Scientific, USA

Motor control platform

DM422s

Wuhan Hongxingyang Technology Co., Ltd

2.2 Preparation of Cationic CNF Ink and Fluoroalkylsilane CNF Ink First, bleach the eucalyptus pulp with sulfuric acid for alkalization treatment, then transfer it to a sealed bag, and add a specific amount of EPTMAC and 100 mL of isopropanol [13]. After the reaction, the resulting cationic fiber suspension with a 1% concentration is processed using a high-pressure homogenizer. To adjust the ink’s viscosity for printing, MC is added. In this experiment, single-particle-size dispersed nano SiO2 was prepared using the Stober method. The CNF preparation process is illustrated in Fig. 1a. CNF solution (1 wt%) was mixed with nano SiO2 and magnetically stirred for 2 h. The absolute weight of SiO2 was 10 wt%, 20 wt%, 30 wt%, 40 wt%, and 50 wt% of the absolute dry mass of CNF, respectively. Subsequently, the sample was injected into a high-pressure homogenizer, and the CNF-SiO2 hydrogel was obtained by recycling under a certain pressure. Finally, a specific amount of MC was added to produce a printable ink. The two prepared inks are displayed in Fig. 1b. 2.3 Preparation of TENG Friction Layer The TENG friction layer is primarily prepared by blending CNF hydrogel and MC to create an ink, and the three-dimensional framework structure can be directly written and is depicted in Fig. 1c. After printing, it is subjected to 10 h of drying in a freeze-drying machine. To achieve a porous lamellar aerogel structure, the resulting positive friction layer is placed in an 80 °C oven for thermal annealing treatment lasting 30 min. When preparing the fluorosilicated CNF friction layer, the CNF-SiO2 aerogel should undergo PFOTS chemical vapor deposition modification following annealing. The fluorosilication process is illustrated in Fig. 1d. 2.4 Assembly of TENG Devices Two different TENGs were constructed using cationic-modified CNF friction layers with PDMS and PET plates with FCNF-SiO2 friction layers. Attach an appropriately sized conductive adhesive to the substrate of a 50 mm2 PET plate, secure the previously prepared negative friction layers onto the conductive adhesive, and connect them to the wires. The TENG devices were assembled in a vertical contact separation mode, in which they came into face-to-face contact with the PET board.

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3 Results and Discussion Cationic modification of CNF involves a nucleophilic reaction between the activated hydroxyl group of CNF and the epoxy group of EPTMAC. However, the primary etherification reaction is also accompanied by alkaline hydrolysis [14]. During the cationic process, EPTMAC is consumed in the competition between the two reactions: EPTMAC hydrolysis reaction and CNF cationic hydrolysis reaction (Fig. 1a) [15]. The higher the water content in the reaction system, the more pronounced the hydrolysis effect of EPTMAC. Consequently, a lesser amount of EPTMAC is available for cationic reactions. To confirm the success of CNF cationic modification, we analyzed the ink using the Fourier transform infrared spectroscopy (FTIR) measurement method. Figure 1b displays the FT-IR spectra of cationically modified CNF. The comparison reveals that the stretching vibration peak (3413 cm−1 ) of hydroxyl groups is significantly attenuated. This reduction occurs due to the cationic modification of the fibers, where the hydroxyl groups are replaced, resulting in a weakening of the hydrogen bonding effect. The observed trend in peak strength change aligns with the change in charge density. To achieve a three-dimensional layered friction layer structure through DIW, it is necessary to use an ink with appropriate viscoelasticity and good dispersion. Figure 1c illustrates the relationship between shear rate and apparent viscosity. The viscosity of the cationic ink decreases with an increase in shear rate, approaching linear deformation, and exhibiting typical shear-thinning behavior, which allows the ink to smoothly flow through the nozzle during the printing process. To explore the viscoelastic properties of the ink, we present the oscillatory shear rheology characteristics in Fig. 1d. A distinctive feature of both G and G curves is their division into two parts: initially, they remain relatively stable, followed by a downward trend. When G is greater than G , the cationic ink primarily exhibits elastic deformation. This is due to the presence of forces between the molecules and molecular chains within the ink. When subjected to shear forces, the ink’s elasticity remains stable, maintaining its shape when the applied force is insufficient to overcome the internal forces of the ink. However, when the applied force exceeds a certain threshold, both G and G start to decrease. At a certain point, G surpasses G , indicating that the cationic ink primarily undergoes viscous deformation. At this stage, the internal structure of the ink has been disrupted, and the adhesive properties of the ink become dominant over its elastic properties. This meets the rheological behavior standards required for DIW technology. To confirm the successful modification of CNF with fluorosilane, we conducted infrared analysis on CNF, FCNF, CNF-SiO2 aerogel, and FCNF-SiO2 friction layer aerogel (both CNF-SiO2 aerogel and FCNF-SiO2 friction layer aerogel were selected as representatives for analysis at a 10:5 ratio). It was observed that FCNF and FCNF-SiO2 aerogel samples, as well as CNF aerogel samples, exhibited significant differences before and after the chemical vapor deposition (CVD) process. The peaks at 3344 cm−1 and 1730 cm−1 can be attributed to the stretching vibrations of -OH and -COOH groups of cellulose, respectively. The C-O stretching vibration peak of CNF appears at 1056 cm−1 . The typical Si-O-Si bond absorption peak of FCNF aerogel and FCNF-SiO2 friction layer aerogel samples overlaps with the C-O bond of CNF in the range of 1130–1000 cm−1

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a.Competitive reactions during the cationic modification of cellulose fibrils using EPTMAC/H2O/NaOH system b.FT-IR spectrum of cationically modified CNF c.Linear relationship between shear rate and apparent viscosity of cationic modified CNF ink d. Cationic modified CNF ink modulus as a function of shear strain. Fig. 1. Preparation and Characterization of cationic modified CNF Ink.

[25], as shown in Fig. 2a. Additionally, the CNF-SiO2 ink can exhibit viscous deformation and has the ability to extrude smoothly and uniformly, as depicted in Fig. 2b and c. Aerogels with identical surface morphologies were chosen to investigate the influence of the matrix on hydrophobicity. As illustrated in Fig. 2d, all aerogels exhibited excellent hydrophobicity, and the hydrophobicity, as well as the average contact angle (CA) of CNF-SiO2 aerogel and FCNF-SiO2 friction layer aerogel, increased with the higher mass ratio of dried fiber to SiO2 . To achieve surfaces with high hydrophobicity, the addition of SiO2 serves two purposes: it provides chemical reaction sites, facilitating the chemical vapor deposition process, and it increases the micro-roughness of the surface. This increase in micro-roughness reduces the contact area between the liquid and the surface, consequently enhancing hydrophobicity. The hydrophobic property of FCNF-SiO2 friction layer aerogel primarily results from the gradual increase in SiO2 content on the surface and within the internal pores of CNF aerogel. This increase in SiO2 content leads to a higher concentration of F elements, as well as the augmentation of -OH reaction alkyl chains on the surface of PFOTS and SiO2 particles due to CVD deposition. The fluorinated contact angle (CA) increases from 142.8° with a mass ratio of 10:1 to 150.6° with a mass ratio of 10:5, achieving a superhydrophobic state.

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a.FT-IR spectrum of fluorosilication modified CNF b.Linear relationship between shear rate and apparent viscosity of fluorosilication modified CNF ink c.Fluorosilication modified CNF ink modulus as a function of shear strain d.The contact angle of

CNF-SiO2 aerogel and FCNF-SiO2 friction layer aerogel Fig. 2. Preparation and Characterization of fluorosilication modified CNF Ink.

It is expected that CNF with an improved surface interface can enhance the electrical output performance of TENG. The prepared friction layer is connected to the electrodes and the load to create a contact-separated TENG, as shown in Fig. 3a. Consequently, two different TENGs are constructed using cationically modified CNF friction layers with PDMS and PET plates with FCNF-SiO2 friction layers. The TENG output performance (T = 23.7 °C, RH = 45%) of various positive friction layers, prepared with EPTMAC and absolute dry fiber mass ratios of 1.0, 1.5, 2.0, 2.5, and 3.0, combined with PDMS negative friction layers, is depicted in Fig. 3b. When the ratio of EPTMAC to dry fiber mass is below 2.0, the output voltage gradually increases with the amino content, and the overall open-circuit voltage (V oc ) ranges from 100V to 300V. When the ratio is 2.0, the output voltage reaches a maximum of 273 V, but the voltage slightly decreases as the ratio gradually increases. The short-circuit current (I sc ) is around 200 nA, and the change is not significant, yet it is sufficient to charge four capacitors with different capacities (1 F, 2.2 F, 3.3 F, 10 F), as depicted in Figs. 3c–d. The TENG output performance (T = 23.7 °C, RH = 45%) of various positive friction layers, prepared with mass ratios of dry fibers and SiO2 at 10:1, 10:2, 10:3, 10:4, and 10:5, respectively, combined with PDMS negative friction layers, is presented in Fig. 3e. The output voltage gradually increases with the increasing mass ratio of dried fiber to SiO2 . Especially when the ratio is 3.0, the fluorosilane on the surface of the FCNF-SiO2 friction layer aerogel reaches its maximum value. At this point, the electron absorption ability is the strongest, resulting in an output voltage of 400 V. The I sc ranges from 20–60 nA, with insignificant changes. Nevertheless,

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it is sufficient to charge four capacitors with different capacities (1 mF, 2.2 mF, 3.3 mF, 4.7 mF), as depicted in Figs. 3f–g. The results demonstrate that the three-dimensional structure aerogel composed of cationically modified and fluorosilane-modified CNF exhibits excellent electrical output performance.

a. Structural schematic and schematic diagram of TENG b. Open circuit voltage Voc of TENG composed of cationic modified CNF and PDMS c. Short circuit current Isc of TENG composed of cationic modified d. Capacitor charger application of TENG composed of cationic modified CNF and PDMS e. Open circuit voltage Voc of TENG composed of FCNF-SiO2 and PET f. Short circuit current Isc of TENG composed of FCNF-SiO2 and PET. g) Capacitor charger application of TENG composed of FCNF-SiO2 and PET Fig. 3. Application of Modified CNF in TENG

4 Conclusions In conclusion, the introduction of surface groups -NH2 and -F through chemical treatment enhances CNFs’ ability to gain or lose electrons or alters their polarity, thereby improving the material’s frictional electrical properties. The application of functionalized CNFs to TENG can lead to higher energy efficiency, while chemical bonding significantly enhances the durability of friction layer materials. The results demonstrated that when the mass ratio of EPTMAC to cellulose was 2.0, the degree of cationicity was the highest. The introduction of -F, achieved using nano SiO2 and PFOTS, not only renders the water contact angle of FCNF-SiO2 aerogel superhydrophobic at 150° but also reaches the maximum output voltage when the mass ratio of the dried fiber to nano SiO2 is 3.0. This further underscores the irreplaceable advantages and practical application value of CNFs in the new environmentally friendly mechanical energy collection system, TENG.

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Acknowledgements. This work was supported by National Natural Science Foundation of China (No. 52203049).

References 1. Wu, C., Park, J.H., Koo, B., et al.: Capsule triboelectric nanogenerators: toward optional 3D integration for high output and efficient energy harvesting from broadband-amplitude vibrations. ACS Nano 12(10), 9947–9957 (2018) 2. Xiao, T.X., Liang, X., Jiang, T., et al.: Spherical triboelectric nanogenerators based on springassisted multilayered structure for efficient water wave energy harvesting. Adv. Funct. Mater. 28(35), 1802634 (2018) 3. Yin, X., Liu, D., Zhou, L., et al.: Structure and dimension effects on the performance of layered triboelectric nanogenerators in contact-separation mode. ACS Nano 13(1), 698–705 (2019) 4. Rajabi-Abhari, A., Kim, J.N., Lee, J., et al.: Diatom bio-silica and cellulose nanofibril for biotriboelectric nanogenerators and self-powered breath monitoring masks. ACS Appl. Mater. Interfaces 13(1), 219–232 (2021) 5. Bao, Y., Wang, R., Lu, Y., et al.: Lignin biopolymer based triboelectric nanogenerators. APL Mater. 5(7) (2017) 6. Zhao, L., Zheng, Q., Ouyang, H., et al.: A size-unlimited surface microstructure modification method for achieving high performance triboelectric nanogenerator. Nano Energy 28, 172–178 (2016) 7. Xia, K., Tang, H., Fu, J., et al.: A high strength triboelectric nanogenerator based on rigidflexible coupling design for energy storage system. Nano Energy 67, 104259 (2020) 8. Parandeh, S., Kharaziha, M., Karimzadeh, F.: An eco-friendly triboelectric hybrid nanogenerators based on graphene oxide incorporated polycaprolactone fibers and cellulose paper. Nano Energy 59, 412–421 (2019) 9. Lu, Y., Li, X., Ping, J., et al.: A flexible, recyclable, and high-performance pullulan-based triboelectric nanogenerator (TENG). Adv. Mater. Technol. 5(2), 1900905 (2019) 10. Zhao, D., Zhu, Y., Cheng, W., et al.: Cellulose-based flexible functional materials for emerging intelligent electronics. Adv. Mater. 33(28), 2000619 (2020) 11. Klemm, D., Kramer, F., Moritz, S., et al.: Nanocelluloses: a new family of nature-based materials. Angew. Chem. Int. Ed. Engl. 50(24), 5438–5466 (2011) 12. Bang, J., Moon, I.K., Jeon, Y.P., et al.: Fully wood-based green triboelectric nanogenerators. Appl. Surface Sci. 567, 150806 (2021) 13. Christian, A., Erik, J., Lars, W., et al.: Self-organized films from cellulose I nanofibrils using the layer-by-layer technique. Biomacromolecules 11(4), 872–882 (2010) 14. Peng, F., Ren, J.L., Xu, F., et al.: Comparative study of hemicelluloses obtained by graded ethanol precipitation from sugarcane bagasse. J. Agric. Food Chem. 57(14), 6305–6317 (2009) 15. Li, S., Zhang, S., Wang, X.: Fabrication of superhydrophobic cellulose-based materials through a solution-immersion process. Langmuir. 24(10), 5585–5590 (2008)

Development Trends of Paper and Fabric Based Printed Electronics Technology Fangdong Wang1 , Luhai Li1(B) , Lixin Mo1 , Meijuan Cao1 , Yinjie Chen1 , Zhiqing Xin1 , Yi Fang1 , Xiaoyin Meng1 , and Hongqi Chen2 1 Beijing Institute of Graphic Communication, Beijing Engineering Research Center

of Printed Electronics, Beijing, China [email protected] 2 Guangdong Olger Precise Machinery Technology Company Limited, Guangdong, China

Abstract. Paper and fabric substrates are important foundational materials for the fabrication of flexible and printed electronic devices. This paper combines the research work undertaken for the project and, based on a review of the literature, comprehensively summarizes the roles, classifications, and processing techniques of paper-based and fabric materials in flexible and printed electronics. It compares the preparation techniques of such devices and introduces the achievements of chemical sintering and in-situ polymerization on paper-based electronics. Literature retrieval and analysis indicate that the development of paper-based/fabric electronic devices is essentially synchronized both domestically and internationally. It is believed that paper-based/fabric-based flexible electronic devices, including but not limited to circuits, electrodes, RFID tags, sensors, energy storage, and conversion devices, have their respective applications: paper-based devices are suitable for disposable, low-cost applications, while fabric-based devices are more suitable for wearable electronic products. Overall, in line with global carbon emissions control efforts, conductive and semiconductor materials suitable for fabric/paper-based flexible electronic products, including nano metals, conductive polymers, carbon materials, MXene, and other materials, will be prioritized for development. The related fabric/paper-based coating and printing industries will also rise in tandem with this trend. Keywords: flexibility and printing electronics · paper-based electrons · fabric electronics · flexible devices preparation · wearable electronics

1 Introduction The demand for various flexible printed electronic devices is rapidly increasing. The printed electronics market is expected to grow at a compound annual growth rate of 18.3%, from $9.9 billion in 2021 to $23 billion in 2026 [1]. Concurrently, roll-to-roll manufacturing is gaining popularity in the electronics industry, driving research into novel flexible substrate materials suitable for printing processes. Flexible paper-based substrates and flexible fiber textile substrates are widely studied and gaining attention due to their advantages such as flexibility, stretchability, breathability, and biodegradability [2, 3]. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 162–171, 2024. https://doi.org/10.1007/978-981-99-9955-2_22

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Paper-based substrates are particularly prominent in the field of flexible electronics due to their low cost, flexibility, and biodegradability [4]. The ability for largearea printing processes makes electronic paper promising for applications in wearable devices, energy conversion, electronic skins, and smart sensors, among other areas [5, 6]. Electronic textiles made from textile substrates offer soft texture, comfortable wear, high energy conversion, ease of integration, and serve as a versatile platform for advanced wearable electronic devices [7, 8]. Electronic textile-based devices are primarily used in wearable electronics for monitoring physical parameters and biometric signals, energy storage and harvesting devices, as well as signal transmission and communication systems [9, 10]. This paper begins by reviewing the types of paper-based and textile-based substrates and various functional materials used in the fabrication of electronic paper and electronic textiles. It then explores the methods for producing flexible printed electronic devices on electronic paper and electronic textiles. The emerging applications of paper electronics and electronic textiles in areas such as circuits, energy storage, sensors, and more are introduced and discussed. Subsequently, recent trends in literature related to paper-based and textile-based substrates are analyzed. Finally, the paper concludes with a summary and provides prospects for future research work.

2 Paper-Based and Fabric-Based Printed Electronic Materials 2.1 Paper-Based Electronic Materials Paper-based electronic devices are primarily developed through process modifications or the incorporation of functional materials to enhance the properties of paper, rendering it as transparent paper or electronic paper. Common paper substrates include cellulose paper, graphene paper, carbon fiber paper, and composite papers. Table 1 provides a summary of commonly used paper substrate types, fabrication methods, characteristics, and applications for flexible and printed electronics. Various paper-based materials are applied in the field of flexible electronics. For example, Li et al. [11] have developed paper made from cellulose nanofibers (CNF) and silver nanowires (AgNW), which is highly transparent, flexible, and exhibits low sheet resistance. Lv et al. [12] have prepared graphene paper (GP) as a flexible electrode material, and when combined with polyaniline, the composite material achieves a specific capacitance of up to 759 F/g at a current density of 1 A/g. Carbon fiber paper has been used as a conductive electrode and substrate for lithium-ion batteries, fuel cells, and supercapacitors. Composite papers can be manufactured to meet the specific substrate requirements of different devices. 2.2 Textile Substrate Fabric, a 3D fiber component, is porous and highly deformable, offering benefits like softness, comfort, breathability, warmth retention, durability, and washability. Textile materials are categorized into natural, synthetic, and blended fibers. Refer to Table 2 for details on the types and attributes of flexible and printed electronic textile substrates.

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Type

Preparation method

Cellulose paper Micron cellulose Including pulp paper and paper

Characteristic

Application

Abundant sources, low price, biodegradable and biocompatible, R2R production

RFID, sensors, flexible displays, solar cells and various energy storage devices

Nanocellulose paper

Chemical, physical, biological, or a combination of these

Good flexibility, good thermal stability and high transparency

OTFT, OFET, OLED, solar cells, displays

Graphene paper

Oxidized graphene paper, reduced graphene oxide paper, and functional graphene paper

Vacuum filtration method, freeze-drying and compression method

Unique electrical transmission properties, high thermal stability, and excellent mechanical strength

Electrically active artificial muscles worn by the body, wearable energy supply, biomedical applications

Carbon material paper

Carbon fiber paper, carbon nanotube paper

Wet papermaking process and dry process

Good conductivity, water resistance, low cost, and mass production

Conductive electrodes and substrate for lithium-ion batteries, fuel cells, and supercapacitors

Composite material paper based

Biological Coating composite paper base

Used as a food packaging barrier for moisture, oil, and oxygen, antibacterial properties, etc.

Used as a food packaging material for water blocking, oxygen blocking, and antibacterial purposes

Composite paper Physical or Simple based materials chemical methods production such as process, good cellulose, conductivity, high graphene, and mechanical carbon strength, and microfibers good flexibility

Wearable electronic products, energy devices, etc.

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Table 2. Common Textile Substrates for Flexible and Printed Electronics Type

Characteristic

Natural textile fibers

Cotton, silk, wool, etc. Natural fibers are composed of macromolecules with high molecular weight and high fiber arrangement

Synthetic textile fibers

Polyester, nylon, spandex, etc.

For the production of synthetic fibers, the molecular weight of the polymer determines the processability and mechanical properties of the resulting fibers

Composite textile fiber

Cotton/spandex, cotton/polyurethane, cotton/wool, nylon/polyurethane, and nylon/spandex, among others

Blending is typically used to optimize the performance of textiles for specific applications, with the aim of compensating for its shortcomings by mixing one fiber type with another

Application Electronic skin, energy systems, sensors, displays, healthcare and other applications, mainly used for wearable electronic devices

The textile substrates for flexible printed electronic devices come in various forms, including fibers, yarns, fabrics, and clothing. They are classified based on their sources into natural textile substrates, synthetic textile substrates, and composite textile substrates. Gurarslan et al. [13] produced knit wool fabric with a silver nanowire coating for monitoring joint movements and abdominal respiration. Textile substrates based on polyester are often produced using coating, screen printing, and inkjet printing techniques and find widespread applications in monitoring pulse, respiration, heart function, body temperature, as well as military applications (tents, military clothing). Blended textiles are typically used to enhance the performance of textiles for specific applications. The goal is to compensate for the deficiencies of one fiber type by blending it with another. Cheng et al. [14] prepared composite superhydrophobic silk fabric exhibiting excellent mechanical durability and cyclic abrasion resistance. However, there are some key challenges in promoting the commercialization of textile substrates, such as application stability, the integration of functional textiles with traditional textiles, safety, and scalable manufacturing. Therefore, to achieve multifunctionality in the next generation of smart textiles, manufacturing processes and application characteristics of different textile substrates should be made more practical, intelligent, and autonomous.

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2.3 Functional Materials The functional materials for paper and textile flexible devices are conductive materials, and common conductive materials include metal materials, carbon materials, conductive polymer materials, and emerging two-dimensional layered materials like MXene. With the rapid development of nanomaterials, metal nanoparticles and metal nanowires have garnered widespread attention in the field of printed electronics. The author’s research group has conducted extensive studies on AgNPs conductive inks and low-temperature sintering on paper-based substrates [15], as well as providing an overview of room-temperature sintering of AgNPs inks [16]. Furthermore, the research group has employed a pre-embedded chemical sintering agent approach for chemically sintering AgNPs on absorbent substrates, with results indicating that embedding a certain amount of potassium chloride can achieve rapid room-temperature sintering of AgNPs inks. Carbon-based conductive materials mainly include conductive carbon black, graphite, graphene, carbon nanotubes, and their derivatives. Conductive polymers primarily include polyaniline, polypyrrole, and polythiophene. Among them, polypyrrole (PPy) is favored for its high conductivity, good environmental adaptability, excellent redox properties, and simple preparation. In our research group, we successfully deposited polypyrrole (PPy) and cellulose nanocrystals (CNCs) on various fiber substrates via inkjet printing, creating PPy/CNCs composite materials. We also fabricated three devices based on PPy/CNCs conductive paper [17]. MXene, with its unique layered structure, outstanding physical and chemical properties, and customizable surface functional groups, has attracted attention in the field of flexible and printed electronics and finds extensive applications in energy storage, sensing, electromagnetic shielding, and various other domains. In our research group, we have previously provided a comprehensive analysis of the research progress of MXene in the field of flexible and printed electronics [18].

3 Preparation of Paper Based and Fabric Printed Electronic Devices 3.1 Preparation of Paper-Based Electronic Devices Currently, there are numerous methods for fabricating paper-based flexible electronic devices. Paper electronics products typically prioritize low cost over resolution, which is why coating and roll-to-roll printing processing methods are widely applied. Coating technology is commonly used to create a uniform functional film across the entire substrate. Various coating techniques such as dip-coating, spray-coating, vacuum filtration, and drop-casting are extensively employed in the processing of paper-based flexible electronic devices. Professor Lu Hai Li from Beijing Institute of Graphic Communication provides a detailed overview of various coating techniques and their applications in the field of printed electronics in his book “Coating and Lamination Technology” [19].

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3.2 Preparation of Textile Fiber Electronic Devices Currently, three major categories of methods are primarily used to obtain flexible composite conductive fibers: physical coating, chemical processes, and spinning techniques. Physical coating methods involve directly applying functionalized materials onto fiber/yarn/textile substrates. Chemical methods involve the in-situ chemical growth of various active materials on fiber/yarn/textile substrates. Spinning technology allows for the mass production of inherently conductive fibers/yarns/textiles and can be used to prepare fiber-based flexible electronic devices using PEDOT fibers, GO fibers, MXene/GO fibers, CNT fibers, and other composite fibers.

4 Application of Paper/Textile Based Flexible Electronic Devices Paper based, textile based, or related composite substrates can be used to prepare different functional electronic devices to meet various application needs. Paper based electronic devices are suitable for disposable low-cost electronic devices, and fabrics are more suitable for wearable electronic products. According to different functions, paper based and textile based flexible electronic devices can be divided into basic electronic components (i.e. circuits, electrodes, RFID tags), sensors, energy storage and conversion devices, and other applications. Here, we mainly cite some representative examples to demonstrate the unique properties of paper and textile substrates that bring special functions to electronic devices. 4.1 Circuits, Electrodes, and RFID Tags Conductive circuits and electrodes are fundamental components of various electronic devices. Pre-designed circuit patterns can be easily created on paper and fabric by printing conductive inks/pastes. These printed circuits can be folded, bent, and stretched, demonstrating excellent flexibility. For example, Li et al. [20] introduced a stretchable woven fabric circuit board (FCB) that can be connected to sensors or other wearable electronic components and stretched up to 30% strain. Yuan et al. [21] used a liquidphase chemical reduction method to prepare nano silver and, in combination with inkjet printing technology, fabricated circuits on textile substrates. Textile capacitive sensors prepared based on this circuit demonstrate stability after 1500 repeated load cycles and effectively monitor human heart rate and ECG signals by connecting textile electrocardiogram (ECG) electrodes to a support structure. Electrodes based on flexible paper and textile substrates have gained significant attention in the manufacturing of high-performance sensors and energy storage devices due to their large surface area, excellent deformability, and sufficient material exchange channels. Different functional electrodes have been produced on paper and fabric for wearable electronic devices, such as supercapacitors and strain sensors [22, 23]. To produce low-cost flexible RFID tags, dipole antennas are typically printed on paper and fabric using conductive inks made from silver or carbon-based materials [24].

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4.2 Sensors Physical sensors based on paper and textile substrates can detect parameters such as pressure, strain, humidity, and temperature, making them widely applicable in flexible wearable electronic devices. For instance, Zhao et al. [23] recently reported an alltextile, all-organic, washable, and breathable sensor with distinguishable pressure and temperature sensing capabilities. Developed using highly conductive thermosensitive PPY/cotton fabric, this all-textile, all-organic multifunctional sensor exhibits excellent performance in pressure, proximity, and temperature sensing. Chemical sensors are often used as gas sensors (for detecting toxic and flammable gases in the environment) and for sensing physiological signals in liquid samples (such as serum, urine, and sweat). 4.3 Energy Storage Equipment To meet the energy requirements of flexible electronic devices, various energy storage and conversion devices have been invented. Typical energy storage devices include supercapacitors and batteries, and paper and textiles have been widely used as electrodes, electrolytes, and substrates for supercapacitors. Electrochemically active cellulose-based electrodes can be produced by integrating cellulose fibers with metals, carbon-based materials, polymers, MXene, or their composites. To date, various types of paper-based or paper-like batteries and energy storage devices have been developed, including selfpowered fluorescence detection microfluidic devices based on paper-based flow batteries, urine-activated paper batteries for bio-system-driven applications, light-triggered electrochemical microfluidic paper chips with integrated paper-based supercapacitors, paper-based microbial fuel cells for disposable diagnostic devices, and paper-based lithium-ion batteries with high energy density output, among others. Our research group has published several patents related to zinc-air paper batteries and their applications [25, 26]. Cellulose paper/textile substrates can be used to develop biodegradable green energy storage devices. Chen et al. [27], for instance, designed a novel superhydrophobic conductive fiber (SEBC fiber) based on bacterial cellulose (BC) and constructed a self-cleaning and anti-fouling biodegradable superhydrophobic textile-based nanotriboelectric generator (SF-TENG). This device is capable of monitoring motion under various pollution and complex environmental conditions, demonstrating the potential application of the constructed SF-TENG in the field of wearable devices.

5 Paper Based/Fabric Electronic Literature Analysis Retrieve international and domestic EI databases and create Fig. 1a. As shown, the number of domestic papers on paper-based electronic devices has been steadily increasing since 2009, with a significant uptick in 2016 and a rapid surge in 2021. Figure 1b illustrates the recent trends in international and domestic paper-based electronics, and all of the data indicate the rapid development of paper-based electronics. The reasons behind this growth can be attributed to the development of nanomaterials and printed electronics industries. Additionally, the imposition of a non-biodegradable plastic packaging tax by the European Union in 2021 has further fueled the demand for paper-based electronic products.

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a.Trend of Paper Based Electronic Literature Publication in China (EI Search); b.Annual Trend of Paper Based Electronic Literature Publication at Home and Abroad Fig. 1. Trend of Paper Based Electronic Literature Publication

The electronic products associated with fabric base in the world are mainly intelligent electronic fabrics, flexible electronics and wearable electronics (Fig. 2a), which are almost synchronized with those in China in terms of publication time (Fig. 2b).

a.Annual Distribution of Textile Electronic Articles at Home and Abroad b.Distribution of international textile electronic literature in publication years Fig. 2. Distribution of Textile Electronic Articles

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6 Conclusion and Prospect With the development of IoT (Internet of Things) technology, the consumer market for flexible electronic sensors is rapidly expanding. Technologies related to paper-based and textile-based electronic materials and manufacturing processes are developing in tandem. (1) Textile and paper-based materials suitable for electronic products will become a significant demand in the flexible electronic product market. Industries related to textile and paper-based coating and printing will also see synchronous growth. (2) Materials suitable for textile and paper-based flexible electronic products, such as conductors and semiconductors, including nanometals, conductive polymers, carbon materials, MXene, and others, will experience prioritized development. (3) Technologies for textile and paper-based flexible electronic products will primarily focus on flexible circuit fabrication, followed by flexible sensor fabrication and applications. Dominant products will include wearables, health monitoring devices, and medical rehabilitation tools. Overall, the technology and market for textile and paper-based flexible electronic products are in a stage of synchronous growth both domestically and internationally. While previous research was primarily conducted by research institutions and higher education institutions, recent developments have seen the emergence of scaled products like flexible paper watches in Germany. The market for textile and paper-based flexible electronics, which involves multidisciplinary and technologically integrated consumer electronic products, has the potential to become substantial once it fully takes shape, making it worthy of attention. Acknowledgements. This research was supported by Beijing Nature Foundation (KZ202110015019), Beijing Institute of Printing and Technology Research Platform Construction (20190223003) and Beijing Municipal Education Commission (KM202110015007).

References 1. Markets and Markets. Printed-electronics-market (2020). https://www.marketsandmarkets. com/Market-Reports/printed-electronics-market-197.html 2. Medeiros, M., Chanci, D., Martinez, R.: Moisture-insensitive, self-powered paper-based flexible electronics. Nano Energy 78, 9–13 (2020) 3. Uzun, S., Schelling, M., Hantanasirisakul, K., et al.: Additive-free aqueous MXene inks for thermal inkjet printing on textiles. Small 17, 2006376 (2020) 4. Razaq, A., Bibi, F., Zheng, X., et al.: Review on graphene-, graphene oxide-, reduced graphene oxide-based flexible composites: from fabrication to applications. Materials 15, 1012 (2022) 5. Hassan, M., Abbas, G., Li, N., et al.: Significance of flexible substrates for wearable and implantable devices: recent advances and perspectives. Adv. Mater. Technol. 7, 2100773 (2021) 6. Xu, Y., Fei, Q., Page, M., et al.: Paper-based wearable electronics. iScience 24, 102736 (2021)

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7. Jin, C., Bai, Z.: MXene-based textile sensors for wearable applications. ACS Sens. 7, 929–950 (2022) 8. Yin, J., Li, J., Reddy, Y., et al.: Flexible textile-based sweat sensors for wearable applications. Biosensors 13, 127 (2023) 9. Zhu, Y., Yang, M., Huang, Q., et al.: V2O5 textile cathodes with high capacity and stability for flexible lithium-ion batteries. Adv. Mater. 32, 1906205 (2020) 10. Zhang, M., Zhao, M., Jian, M., et al.: Printable smart pattern for multifunctional energymanagement E-textile. Matter 1, 168–179 (2019) 11. Li, R., Zhang, K., Chen, G.: Highly transparent, flexible and conductive CNF/AgNW paper for paper electronics. Materials 12, 322 (2019) 12. Lv, F., Xiong, S., Wang, X., et al.: Electrochemical fabrication of polyaniline/graphene paper (PANI/GP) supercapacitor electrode materials on free-standing flexible graphene paper. High Perform. 33, 1124–1131 (2021) 13. Gurarslan, A., Özdemir, B., Bayat, ˙I, et al.: Silver nanowire coated knitted wool fabrics for wearable electronic applications. J. Eng. Fibers Fabrics 14, 1558–9250 (2019) 14. Cheng, Y., Zhu, T., Li, S., et al.: A novel strategy for fabricating robust superhydrophobic fabrics by environmentally-friendly enzyme etching. Chem. Eng. 355, 290–298 (2019) 15. Mo, L., Guo, Z., Wang, Z., et al.: Nano-silver ink of high conductivity and low sintering temperature for paper electronics. Nanoscale Res. Lett. 14, 197 (2019) 16. Li, L., Lui, Y., Han, L., et al.: Research progress on low-temperature sintering of nanosilver printed circuits. Digit. Print. 2, 10–21 (2023) 17. Li, X., Cao, M., Li, S., et al.: In-situ oxidative polymerization of pyrrole composited with cellulose nanocrystal by reactive ink-jet printing on fiber substrates. Polymers 14, 4231 (2022) 18. Meng, X., Zhao, J., Pan, Y., et al.: Research progress of MXene in the field of flexible and printed. Electronics 3, 41–54 (2021) 19. Li, L.: Coating and Lamination Technology. Printing Industry Press, Beijing (2017) 20. Li, Q., Ran, Z., Ding, X., et al.: Fabric circuit board connecting to flexible sensors or rigid components for wearable applications. Sensors 19, 3745 (2019) 21. Xiao, Y., Li, Q., Zhang, C., et al.: Fabrication of silver electrical circuits on textile substrates by reactive inkjet printing. IEEE Sens. J. 22, 11056–11064 (2022) 22. Say, M., Brett, C., Edberg, J., et al.: Scalable paper supercapacitors for printed wearable electronics. ACS Appl. Mater. Interfaces 14, 55850–55863 (2022) 23. Zhao, P., Song, Y., Xie, P., et al.: All-organic smart textile sensor for deep-learning-assisted multimodal sensing. Adv. Func. Mater. 33, 2301816 (2023) 24. Kim, S.: Inkjet-printed electronics on paper for RF identification (RFID) and sensing. Electronics 9, 1636 (2020) 25. Mo, L., Pan, Y., Li, L., et al.: A flexible smart oxygen packaging device: CN202121623387.8[P]. 29-11-2022 26. Mo, L., Pan, Y., Li, L., et al.: A flexible self-powered oxygen sensor and oxygen content testing device: CN202121623337X[P]. 08-03-202 27. Chen, K., Li, Y., Yang, G., et al.: Fabric-based TENG woven with bio-fabricated superhydrophobic bacterial cellulose fiber for energy harvesting and motion detection. Adv. Funct. Mater. 2023, 2304809 (2023)

Research on “Dragon Scales” Binding Art and Design Tao Zhang1 , Fei Liu1 , Jinglin Ma1(B) , and Peng Zhao2 1 Shandong Communication and Media College, Jinan, China

[email protected] 2 Shandong Jinxing Digital Industry Development Group Co., Ltd., Jinan, China

Abstract. “Dragon scales” binding is an ancient form of binding in China, and this binding technique has not been passed down. Currently, only one physical object exists. In recent years, there have been some successful research and replication of “Dragon scales” binding works, but they have not received unified recognition from the academic community. This paper designs the basic structure and replication method of “Dragon scales” binding based on the two works of “Portraits of Confucius’ disciples” and “Painting of Confucius’ Sacred deeds” through literature research and reference to some replicas of “Dragon scales” binding. Image processing software is used to segment the images, digital printing technology is used to present the images on coated xuan paper, and the printed pages are collaged and mounted to obtain a complete “Dragon scales” binding work, elaborated on the technical issues that need to be paid attention to when designing and producing “Dragon scales” binding works through experiments,develop a path to replicate the ancient binding technique of “Dragon Scale” Binding. Keywords: “Dragon scales” · binding Image processing Inkjet printing

1 Introduction Book binding is an important manifestation of the external appearance of books, and books from different historical periods have different binding forms. China is a country with a long cultural history, and books play a very important role in conveying human civilization. During the Tang Dynasty in China, there was a form of binding called “Dragon scales” binding, which had the characteristics of both scrolls and books. With the gradual popularization of books, the form of “Dragon scales” binding disappeared. Due to war and destruction, most of the physical items bound with “Dragon scales” bindings have also been lost, and currently only one item bound with “Dragon scales” binding is preserved in Beijing, China. “Dragon scales” binding is a unique form of book binding in China, representing the unique cultural and artistic characteristics of China [1]. Studying and replicating “Dragon scales” binding technology has significant positive significance for inheriting and promoting the characteristics of Chinese culture and art. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 172–177, 2024. https://doi.org/10.1007/978-981-99-9955-2_23

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“Dragon scales” binding is the process of sequentially pasting the pages of a book on a long paper, with adjacent pages covered by upper and lower parts. The part where the lower page protrudes from the upper page is called the “Scale edge”. After pasting all the pages, the entire book can be rolled into a scroll, which is very beneficial for book preservation. After the book bound with “Dragon scales binding” is unfolded, all the pages will slightly curl, like dragon scales [2]. Each page is arranged sequentially from right to left, and the graphic and textual content on the pages is coherent, just like a book. Alternatively, the patterns at the palce called “Scale edge” of all pages can be pieced together to form a complete picture, with independent graphic and textual content within each page Inside the “Scale edge” as shown in Fig. 1.

Fig. 1. Form of “Dragon scales” binding

This paper studies the design and production of the “Dragon scales” binding art, with the “Portraits of Confucius’ disciples” created by Li Gonglin, a Chinese painter in the Song Dynasty, and the “Painting of Confucius’ Sacred deeds” created by Kong Xianlan, a chinese wood-block engraver in the Qing Dynasty as the materials, so as to achieve the goal of copying and presenting the ancient technology of “Dragon scales” binding.

2 Design and Image Processing 2.1 Structure and Specifications of the Work The complete design of the work is divided into three parts, namely topic, postscript, and decorative strip, with a total specification of 29 × 695 cm as shown in Fig. 2.The main screen “Portraits of Confucius’ disciples” is decomposed into 53 segments, distributed throughout the first page and at the “Scales edge” on pages 2 to 53. The specification for each page is 29 × 32 cm. The “Painting of Confucius’ Sacred deeds” consists of 105 scenes, distributed on the reverse side of page 1 and in the middle of pages 2 to 53. 2.2 Design of Work Content Paste the complete topic of “Portraits of Confucius’ disciples” on the right end of the long paper, which is equivalent to the title page of a book. At intervals of decorative strips, the first page of the main screen is pasted on the left side of the topic, and the second page is pasted below the first page. At the same time, it is offset to the left by 7 cm. There is a 1 cm wide area on the right side of each page pasted on the long paper as shown in Fig. 3. The main screen is printed on one side of the paper, with each page using a specification of 29 × 64 cm paper, folded in half to create paper with patterns on both sides, achieving overall design intent as shown in Fig. 4.

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Fig. 2. Work structure

Fig. 3. The pages arrangement order.

Fig. 4. The pages folding method.

2.3 Layout Design The width of the “Scale edge” is 7 cm, and the image of the “Scale edge” extends towards the inside of the page with a bleeding of 0.2 cm. The bleeding extends 0.2 cm above and below the layout, and the overall layout size is 66 × 29.4 cm as shown in Fig. 5. The patterns on both sides of the “Scale edge” on the same page are continuous as shown in Fig. 6, so that the front faces of the 53 “Scales edge” can be assembled into a complete image, and the back faces of the 53 “Scales edge” can also be assembled into a complete image.

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Fig. 5. Layout of the 1st page

Fig. 6. Layout of pages 2–53

3 Digital Printing This paper uses digital inkjet printing technology to present content on coated xuan paper. The soft and resilient nature of xuan paper is the best carrier for expressing traditional Chinese calligraphy and painting art. Coated xuan paper can meet the adaptability requirements of digital inkjet printing. Xuan paper has the characteristics of neatness, flexibility, firmness, delicacy, and good coloring power [3], and the use of xuan paper to replicate traditional Chinese calligraphy and painting works of art has profound significance in promoting and disseminating traditional Chinese culture [4].The equipment and materials used in the printing experiment of this paper are shown in Table 1, the printing output effect is shown in Fig. 7. Compared to ordinary xuan paper, coated xuan paper is coated with a coating to prevent ink diffusion, which can lock the ink onto the surface of xuan paper and has strong color reproduction ability. It can make the printed image bright and reproduce the color saturation of the original image well.

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Experimental equipment

Model

printer

Epson 9880

ink

K3 pigment ink

paper

65 g/m2 coated xuan paper

a. Printout b. Cut and folded pages Fig. 7. Digital inkjet printing output effect

4 Binding After folding the printed page in half, cut off the bleeding, start from page 53 and paste it in reverse order on the long paper until it is assembled into a complete “Portraits of Confucius’ disciples”. Use a 1cm wide hot-melt adhesive film and heat it to make the pages stick tightly on the long paper as shown in Fig. 8, completed “Dragon scales” binding is shown in Fig. 9.

a. Trimmed pages b. Paste pages in order Fig. 8. Binding

The reasons for using hot-melt adhesive film instead of glue and double-sided adhesive film in the binding experiment of this article are reflected in two aspects. One reason is that using glue can cause uneven surface of the paper after drying, and the other reason is that using double-sided adhesive can cause obscission due to the aging of the adhesive film.

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Fig. 9. Completed “Dragon scales” binding

Due to errors in the manual operation process, there may be gaps between the finished binding work and the design size. The error data of the experimental work in this paper is shown in Table 2. The reason for the error is the accumulation of errors in the pages collage process and the binding error. The team of this paper will improve the production accuracy in future research. Table 2. Size comparison Project

Main screen width

Total width

Height

design size

396 cm

695 cm

29 cm

Work size

397.4 cm

699.7 cm

29.1 cm

5 Conclusion This article determines the structure of the “Dragon scales” binding through literature review, uses image processing software to decompose the original image of the “Portraits of Confucius’ disciples”, and processes the image of the “Painting of Confucius’ Sacred deeds”, designing 53 image fragments. Using an inkjet printer to output image fragments on coated xuan paper, after folding, trimming, and collage, a long scroll with “Dragon scales” binding was obtained, including the”Portraits of Confucius’ disciples” and “Painting of Confucius’ Sacred deeds”, and the replication mode of “Dragon scales” binding was determined.

References 1. Wei, X.: Exploring the causes of the development of ancient Chinese book binding forms. Art and Design (Theory).07, 48–50,(2008) 2. Zhang, X., Li, H.: The eternal ‘Dragon scales’ binding is now shining again. Printing Technol. 11, 26–28 (2010) 3. Chen, Y., Liu, F., Liu, J., Wu, G.: Design and reproduction of ‘dragon scales’ binding process: take the peony-themed dragon scale outfit as an example. Hunan Packag. 36(06), 85–88 (2021) 4. Ma, G.: Key points for making digital Xuan paper art replicas. Digital Printing. 4, 39–40 (2016)

Packaging Engineering Technology

Recent Advancements in Smart Light-Emitting Packaging: Mechanisms, Technologies, and Applications Jiqing Lian1(B) and Yang Zhang2 1 Shanghai Publishing and Printing College, Shanghai, China

[email protected] 2 University of Shanghai Science and Technology, Shanghai, China

Abstract. Smart luminous packaging is a new type of packaging with intelligent and interactive features. It not only protects products, but also fulfills higher consumer expectations, such as environmental change detection, pattern display, music special effects lighting, and other functions. Especially in the food and pharmaceutical fields, the advantages of this packaging are significant. This article provides a comprehensive introduction to the research status and development trends of smart luminous packaging from four aspects: concept and classification, device principle, key technology, and application and future prospects. It also proposes that the future development direction of smart luminous technology will be more lightweight and reliable, and will create more unique experiences by combining with artificial intelligence and virtual reality technologies. These trends indicate that smart luminous packaging will dominate many industries. Keywords: Smart luminous packaging · Device mechanisms · Innovative application

1 Introduction Smart luminescent packaging has gained much attention in recent years due to the evolving needs and expectations of modern consumers for product packaging. While traditional packaging only served basic protection and aesthetic functions, consumers now demand more interactive and user-friendly packaging with advanced features. The utilization of new technologies and innovative materials to create novel packaging models has given rise to the development of the field of smart luminescent packaging. With the rapid development of cutting-edge technologies such as the Internet of Things and 5G, smart luminescent packaging has a broad range of applications. It can perform multiple functions including detecting environmental changes, creating music special effects lighting, displaying intricate patterns, and more. This technology holds significant advantages in industries such as food and medicine. This article delves into the research and application context of smart luminescent packaging in detail from four perspectives: concept and classification, device principles, key technologies, and application and future prospects [1–3]. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 181–197, 2024. https://doi.org/10.1007/978-981-99-9955-2_24

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1.1 Smart Luminescent Packaging Smart packaging is an advanced packaging form that employs intelligent technology, materials, and design concepts to meet consumer needs for protection, convenience, environmental preservation, and aesthetics. Compared to traditional packaging, smart packaging provides more comprehensive protection and value-added services for products, which can interact with consumers, track product information in real-time, and deliver personalized services. Smart luminescent packaging, as an emerging industry, utilizes electronic components, sensing devices, and program control as its core technologies to achieve high-quality, visual identification effects that significantly increase commercial value [4–9]. With green and sustainable characteristics, smart luminescent packaging can be designed using renewable and biodegradable environmental materials to promote environmental protection. To create greater value in the packaging industry, continuous technological innovation and market promotion are needed alongside the development of richer functional modules [10]. 1.2 Classification of Smart Luminescent Packaging Smart luminescent packaging is a novel packaging material that encompasses intelligent and interactive features, exhibiting various types for further classification analysis. According to the Type of Light. Smart luminescent packaging can be categorized into two main types: white light luminescent packaging and color luminescent packaging. White light luminescent packaging employs various colors of light, such as cold and warm light sources, as well as neutral light sources, to display product information. This approach produces a natural and soft visual effect. On the other hand, color luminescent packaging incorporates vibrant lights combined with imaging techniques, enhancing the color layering of the product. By manipulating color changes, it can create different scenes and visually enrich the presentation of the product (as illustrated in Fig. 1).

Fig. 1. Light-Emitting-Packaging.

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According to the Product Form. Smart luminescent packaging can be classified into three distinct categories: vertical smart luminescent packaging boxes, horizontal smart luminescent packaging boxes, and other types of smart luminescent packaging. Vertical smart luminescent packaging boxes refer to the packaging method that showcases products in a three-dimensional manner, making it particularly suitable for high-end product packaging. Horizontal smart luminescent packaging boxes, on the other hand, involve designs in the form of horizontally-oriented or non-stick bottom card paper cover boxes. When the box is opened, the packaged object experiences slight vibrations, triggering the LED light source to emit light and create a romantic and colorful display effect. Lastly, other types of smart luminescent packaging require the integration of components for manufacturing and completion of corresponding shape designs (Fig. 2).

Fig. 2. (a) Light-printed electronics; (b) Light-smart LEDs.

According to the Display Form. Smart luminescent packaging can be categorized into three distinct types: action information prompt, fancy rainbow/flashing star product, and emotional representation. The action information prompt category serves a practical purpose in areas such as business consultation, traffic memoranda, medical reminders, and emergency rescue situations. Fancy rainbow/flashing star products are typically designed for seasonal festivals, such as smart luminescent packaging with Christmas or Halloween themes, which feature captivating visual effects. The emotional representation category delves into more profound aspects of human nature and values. For example, it involves creating 3D crafts for fathers that embody the concept of “building a strong family foundation” as an everlasting token of cherished family memories in the future (Fig. 3).

Fig. 3. Illuminated OLED bottle label.

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The aforementioned description of the different types of smart luminescent packaging highlights its diversified and highly innovative nature as a new material. These various types of smart luminescent packaging are specifically tailored to cater to different needs in users’ everyday lives, work environments, and entertainment pursuits. As a result, they effectively fulfill users’ demands for novelty, amusement, and practicality in packaging materials. 1.3 Domestic and Foreign Researches Smart luminescent packaging, as a novel packaging technology, has gained significant attention and holds immense potential in various sectors such as commodities, goods, and gifts. Extensive research has been conducted by scholars and enterprises both domestically and internationally to explore the applications and advancements of smart luminescent packaging. Material Research. Scholars have made notable advancements in addressing materialrelated challenges in the development of smart luminescent packaging. For instance, the utilization of advanced materials like polymer materials and graphene has been explored to enhance the durability and hardness of the packaging system, as depicted in Fig. 4 [11–14]. Furthermore, the application of biomedical technology in smart luminescent packaging has shown promising results. Nanomaterials have been employed to improve the sealing properties, sterilization effectiveness, and adsorption capabilities of oxidants in the packaging system. This integration of nanomaterials enhances the overall performance and functionality of smart luminescent packaging [11, 12].

Fig. 4. Schematic illustration of a Maillard reaction [11].

Technology Integration Research. In recent years, researchers and industry representatives have conducted extensive research on technology integration to enhance the overall competitiveness of smart luminescent packaging products. For instance, the integration of sensor technology and circuit board technology allows smart luminescent packaging to achieve more precise operations and prompt feedback responses. This integration also enables the provision of personalized and customized services based on customer preferences, as depicted in Fig. 5 [13]. Intelligent Control Technology. Lately, the integration of intelligent control technology has become prevalent in the design and production of smart luminescent packaging. Notably, wireless communication technology and cloud computing technology, as

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Fig. 5. Model of smart home system based on Raspberry PI and Android device [13].

depicted in Fig. 6, have been utilized to enable remote management and monitoring of packaging materials. This integration facilitates the provision of prompt and efficient support and services tailored to customer requirements [14–16].

Fig. 6. Deep learning-based CSI feedback [16].

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Product Application Research. Smart luminescent packaging has gained widespread adoption owing to its universal application value across diverse product categories, commodities, and gift items. This technology integrates research findings in LED materials and zinc oxide nanowire technology to produce visually-appealing and informative smart luminescent packaging products [17–19]. The comprehensive study of smart luminescent packaging involves areas like materials engineering, technology integration, intelligent control, and product applications with promising prospects for future development. Hence, scientists and industry representatives must continue to explore this domain thoroughly while striving for innovation and improvement.

2 Device Principle of Smart Light-Emitting Packaging Smart light-emitting packaging is a type of functional packaging that capitalizes on new materials, novel processes, and advanced electronic technologies. This technology leverages high-brightness LEDs (light-emitting diodes) as its fundamental component, utilizing circuit board design and controller to achieve luminance effects in visible light. Consequently, the packaging exhibits strong visual impact and ornamentation during dark or night-time environments. In this context, we analyze the technology through three critical aspects: luminescence principle, circuit design, and controller. 2.1 Principle of Luminescence The light source serves as the central component within smart luminescent packaging, enabling the attainment of diverse luminous effects through the adjustment of color, brightness, and flickering speed. Prominent examples of commonly employed light sources comprise LEDs, lasers, OLEDs, and other similar technologies [19–22]. LED. LEDs are the most used light source in smart luminescent packaging due to their high efficiency, long life, rich colors, low power consumption, and color stability. They are composed of primary colors such as red, green, and blue, and changing the voltage can create various luminous effects [22, 23] (Fig. 7). Laser. Laser represents a significantly directional light source that functions through the spontaneous radiation of basic units to emit light. The excitation method induces the jumping of ground state atoms or ions to a high energy level utilizing medium laser. Due to their compact size, high brightness, and diverse color range, lasers find ideal application in environments that demand high-speed and precision control [24]. OLED. OLED, made of organic materials, emits light of different wavelengths and colors through carrier recombination under an electric field or current. It offers high luminous power, fast reaction speed, uniform brightness, and a natural appearance that closely resembles natural light sources. OLEDs in smart light-emitting packaging can achieve various functions like pattern display, environmentally friendly operation, and special lighting effects. They hold great potential for future applications [20, 25] (Fig. 8).

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Fig. 7. Display system configurations. (a) RGB-chip mLED/µLED/OLED emissive displays. (b) CC mLED/µLED/OLED emissive displays. (c) mini-LED backlit LCDs [21].

Fig. 8. Next-Generation luminescent materials through artificial intelligence [19].

2.2 Circuit Design The circuit design of LEDs typically comprises components such as power supply, current limiting resistors, and overvoltage protection. The selection of an appropriate power supply is crucial. In low-power LED applications, a commonly used power source is a battery, often composed of small CR2032 cells. On the other hand, high-power LEDs

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require a suitable converter with an output voltage matching the LED voltage drop to ensure a constant current flow. Additionally, it is essential to incorporate a currentlimiting resistor into the circuit with an appropriate value to prevent excessive current that may damage the LED [26, 27]. 2.3 Controller Smart light-emitting packaging relies on a central controller to create captivating special effects. The controller, typically a single-chip microcomputer or digital integrated circuit, drives and regulates the light source, playing a crucial role in achieving intelligent functionality. Comprising three modules (input terminal, dynamic scanning, and signal processing), the controller receives information, illuminates the LEDs progressively to form desired patterns, and ensures smooth data and video processing. To enhance visual effects, specialized chips like PWM dimming, TM1638 digital tube driver, and WS2812 multi-color lamp series can be utilized for precise control over color, brightness, and flickering frequency. The controller serves as a core component, enabling dynamic changes and evoking emotions in smart light-emitting packaging. Currently, two common types of controllers are available: hardware and software controllers [27]. 2.4 Sensor Sensors play a vital role in smart light-emitting packaging by detecting and converting environmental changes into electrical signals for controlling the lighting [27, 28]. Currently, common sensor types available in the market include: Light Sensor. The light sensor is responsible for measuring the brightness and intensity of the ambient light, enabling the adjustment and adaptive control of the internal light source. When the surroundings are brighter, the light sensor reduces the brightness of the smart light-emitting package. Conversely, when the surroundings are dim, the light sensor increases the brightness of the emitted light. This ensures that the illumination remains appropriate and in harmony with the external lighting conditions [29, 30] (Fig. 9). Infrared Sensor. An infrared sensor is a passive detector that operates based on infrared rays. It effectively detects objects or measures distances from a certain range, subsequently converting these measurements into signal outputs. By means of secondary development of infrared sensors, smart light-emitting packaging can be utilized in various applications related to human-computer interaction. Sound Sensor. A sound sensor is a device that converts sound in the surrounding environment into an electrical signal. It finds extensive applications in audio capture and analysis. In the context of smart light-emitting packaging, sound sensors can be integrated to enable voice response and interaction. By combining sound and light, it enhances the interactivity and engagement of the packaging system.

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Fig. 9. Schematic representation of the Ripe Sense indicator [30].

3 Key Technology of Smart Light-Emitting Packaging Smart light-emitting packaging refers to the integration of LED technology, circuitry, controllers, and other technological advancements into packaging materials. This integration allows for dynamic presentation of packaging effects by manipulating the current brightness and frequency of individual components. In-depth analysis of key technologies employed in smart light-emitting packaging is presented below. 3.1 Preparation Process Selection of Raw Materials. The conventional paper substrate is augmented with polyimide (PI) film to fabricate three distinct light-emitting units: green, iridescent, and purple. Furthermore, conductive coatings, controllers, and miniature batteries are incorporated as additional materials in the smart light-emitting packaging technology [31–33]. Make LED Chips. In practical manufacturing, the production process for smart lightemitting packaging involves the creation of LED chips, followed by their integration onto the paper substrate. The manufacturing of LED chips encompasses the production of spindles, subsequent wafer fabrication, and final cutting into smaller pieces utilizing a cutting machine. Figure 10 illustrates the resulting LED chip, which boasts advantages such as compact size, stable luminescence, and low energy consumption [34]. Make Conductive Lines. Smart light-emitting packaging requires the inclusion of a controller to regulate color and brightness when interacting with switches or buttons. In schemes utilizing white light or tricolor-based light sources, separate control of these sources is necessary, accomplished through conductive lines and controllers located at different positions. Consequently, appropriate conductive lines need to be fabricated on the paper substrate to facilitate signal transmission and control [35, 36].

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Fig. 10. The preparation process of CSP (chip scale package) LEDs

Assembly Production. Smart light-emitting packaging features a distinctive structural design, serving the dual purpose of providing consumers with visually appealing effects while ensuring product reliability and preventing malfunctions. The assembly process typically involves affixing LED chips and conductive wires onto the paper substrate, followed by the installation and assembly of the controller and miniature battery. Test Process. During the testing process, it is crucial to verify the durability of smart light-emitting packaging in order to withstand repair and transfer procedures. Prior to production, comprehensive testing of the product is necessary to ensure high quality and enduring stability in various operational scenarios. Only fully validated and high-quality products can be made available to consumers. Processing Sealing. Smart light-emitting packaging can achieve effective sealing through the utilization of pressing and soft joining technologies. In the pressing approach, high temperature or high pressure is applied to securely fasten each component of the intricate structure in a three-dimensional manner. Additionally, the application of specialized adhesive agents can also contribute to the physical sealing effect. On the other hand, soft joining involves the utilization of flexible materials to provide cushioning, fixation, and protection for the substrate, thereby facilitating the packaging process. In summary, the production of smart light-emitting packaging involves a multifaceted composite process that entails the handling of diverse interfaces and the harmonious integration of different materials to ensure optimal performance and sustainability. By employing scientific organization and coordination, we can successfully manufacture smart light-emitting packaging products that fulfill market demands [37]. 3.2 Technical Key Points Smart light-emitting packaging represents a novel material in the realm of high and new technology. As this technology gains traction in commercial applications, certain

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challenges and pain points have emerged in its research and development. These include the following: Modular Design. Complex smart light-emitting packaging requires the integration of multiple micro-components, such as LEDs, sensors, and wireless communication modules, to achieve intelligent functionality. However, the modular design process faces challenges related to component compatibility, packaging, mounting strategies, and interoperability due to the intricate interconnections among these components. Overcoming these challenges is crucial for ensuring seamless integration and optimal functioning of the modules within the packaging structure. Addressing issues related to component selection, packaging design, mounting techniques, and interoperability is essential to enable the successful integration of micro-components and realize the intelligent capabilities of the packaging material. Power Consumption Control. Power consumption is a significant issue in smart lightemitting packaging, as devices like sensors and LEDs require substantial energy input which can reduce efficiency and service life. To address this, research should aim to balance power consumption and reduce energy usage by optimizing power management strategies through efficient delivery mechanisms, energy-saving designs, and intelligent power control. Using low-power components, energy harvesting, and smart power management solutions are innovative approaches that can help reduce energy consumption. By prioritizing research on power consumption and energy reduction, we can make smart light-emitting packaging more sustainable, efficient, and with longer service life. Composite Process. The production and processing of smart light-emitting packaging is a complex process that requires careful consideration of material balance, joint connections, and circuit design. Efficient production methods must be developed to ensure reliable and high-quality products. To achieve this, extensive research must focus on techniques such as thin film deposition and patterning, optimizing material properties, and coordinating processes. The goal is to create a cohesive system that balances all components, including sensors, LEDs, and power supply, and results in products with enhanced market suitability [38]. Multimodal Interaction. The multi-modal interaction of smart light-emitting packaging is a significant challenge that requires interdisciplinary expertise and investment in integration techniques. Integrating various signals into one integrated system requires collaboration and interdisciplinary research in material science, information technology, and human-computer interaction. The focus should be on designing an efficient and userfriendly interface that integrates different modes of communication, taking into account end-user needs and preferences [39]. Ecological Environment Friendly. The increasing consumer demand for eco-friendly and health-conscious products necessitates the consideration of ecological and sustainability factors in the development of smart luminescent packaging. This entails using safer and environmentally friendly materials, optimizing packaging design to minimize waste and energy consumption, and integrating smart materials into environmentally conscious lifestyles. Interdisciplinary collaboration among researchers, material scientists, designers, and sustainability experts is crucial to achieving these goals and creating

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innovative, visually appealing, and eco-friendly smart luminescent packaging options [40]. In summary, the research challenges concerning future smart light-emitting packaging primarily lie in the domains of modular design, power control, composite material processing, multi-modal interaction, intellectual property protection, and ecological friendliness. These bottlenecks necessitate continuous technological innovation and practical exploration to foster their gradual resolution and facilitate the accelerated and enhanced development of intelligent light-emitting systems [41].

4 Application and Future Prospect of Smart Luminescent Packaging Smart luminescent packaging is a cutting-edge packaging material that integrates advanced technologies such as visual, auditory, and light-based systems. By incorporating suitable materials and electrical components, it enables the realization of various functional capabilities, including automatic sensing and interactive display. Smart luminescent packaging has found extensive applications in diverse sectors such as medicine, food, cosmetics, electronics, household goods, and children’s toys. 4.1 Application Fields of Smart Luminescent Packaging Medical Packaging Field. In the context of medical treatment, smart light-emitting packaging offers not only anti-counterfeiting functionalities for medications but also provides ample illumination for patients while aiding in medication reminders. For instance, the packaging of oral liquids can include pertinent details such as timing, dosage, administration method, and the need to shake the bottle before each dose, thus enhancing convenience for patients. Furthermore, intelligent luminescent materials can be integrated into pharmaceutical packaging to mitigate piracy and counterfeiting. Through technologies like scanning codes or color-changing mechanisms, the authenticity of the medication can be quickly identified and verified [42, 43]. Food Packaging Field. In the field of food packaging, smart luminescent packaging serves primarily to preserve the freshness and prolong the shelf life of food, while also enhancing its visual appeal and informative role. For instance, in an illuminated setting, smart light-emitting packaging exhibits splendid light and shadow effects, captivating the attention of consumers (as depicted in Fig. 11). Additionally, smart light-emitting materials can be utilized in food storage systems to provide real-time alarms based on changing conditions. Furthermore, intelligent sensing technology can monitor the temperature and humidity of food during transportation, effectively preventing contamination or damage. Intelligent luminescence finds application in information transmission within food supermarkets as well, through means such as digital display screens installed on shelves that offer real-time presentation of product quantity, pricing, production dates, and other relevant details, thereby facilitating greater convenience for consumers [27, 43–45].

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Fig. 11. Luminous wine bottles designed by our research group.

Cosmetics Packaging Field. In the realm of cosmetics packaging, intelligent luminescence plays a pivotal role in enhancing product quality and visual aesthetics by showcasing the vibrant hues of makeup items. For instance, integrating intelligent sensing modules into plastic containers or tubes of cosmetic products such as lipsticks, eyeshadows, and nail polishes, and combining them with jewelry elements, results in captivating rhythms, dazzling sparkles, and mesmerizing sprays. This integration has garnered significant market acclaim. Simultaneously, smart light-emitting materials find utility in safety verification within cosmetic packaging as well. By incorporating identification codes or transmission strips, consumers can scan the product packaging’s unique article numbers to ascertain authenticity and gain valuable insights into product usage, as illustrated in the accompanying Fig. 12.

Fig. 12. The cosmetic luminescent packaging box designed by our research group.

Electronic Products Packaging. In the domain of electronic products packaging, smart light-emitting packaging finds extensive usage in the outer casing of mobile phones, tablet computers, and other electronic gadgets. These devices employ dazzling and

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vibrant patterns to catch the attention of consumers, and smart glow enables these patterns to appear more vibrant in dark environments. Moreover, the intelligent sensor boasts of a real-time alarm function as well. For instance, signage posts can be installed within buildings and public spaces that automatically activate when lights are turned off, providing cursor cues for various areas and facilitating convenient navigation services [46]. Household Goods Packaging Field. In the realm of household products packaging, intelligent luminescence is predominantly employed in luminous anti-collision thresholds, air outlets, night lights, and similar products to enhance illumination. Smart lightemitting materials can also facilitate functions such as playing music, generating alarms, and adjusting lighting and brightness within home automation systems. These advancements significantly contribute to the enhancement of quality of life and offer enhanced enjoyment [39].

4.2 Future Development Trend of Smart Light-Emitting Packaging Smart light-emitting packaging, as an emerging packaging form, is poised to witness continuous expansion in its application domains, with an increasingly prominent technological trajectory in the future. The forthcoming advancements in intelligent luminescence technology are expected to render it lighter and more dependable, while also incorporating artificial intelligence (AI) capabilities. Furthermore, when coupled with virtual reality (VR), light-emitting packaging holds the potential to deliver remarkable immersive experiences, thereby pushing the boundaries of sensory engagement. Innovative Material Technology. The future of smart light-emitting packaging is largely dependent on material advancements to develop cost-effective and efficient, yet environmentally friendly materials. Consequently, the industry will increasingly focus its efforts on biodegradable materials development to facilitate building a green, sustainable packaging ecosystem. Improve Product Reliability. To satisfy consumer demand for safety and quality, smart light-emitting packaging must enhance its reliability and stability by incorporating more sophisticated design and manufacturing processes. This includes the deployment of innovative sensor technology and monitoring systems to enable the traceability and early warning function of packaging materials, ensuring their safety and authenticity throughout the entirety of the packaging processes. Strengthen Digital Applications. The future of smart light-emitting packaging entails a deeper integration with digital technology, resulting in the development of a novel packaging system that aligns with the demands of contemporary consumers. For instance, leveraging internet technology will facilitate online purchases and transactions, optimize the customer experience, and streamline the overall procurement and utilization processes, thereby enhancing convenience. Diversification of Promotion Fields. Smart light-emitting packaging is poised to become an all-encompassing product, finding applications across multiple sectors. In addition to the high-end market, this technology can be adopted in industries such as

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healthcare and household products. This necessitates increased marketing investment by businesses, which should promote supply chain integration and collaborative innovation. In conclusion, the future of smart light-emitting packaging relies on continuous technological and managerial improvements, prioritizing resource integration and collaborative innovation to diversify its applications across various industries. By doing so, it can evolve into an eco-friendly, consumer-focused packaging system that aligns with modern consumers’ needs while delivering significant social benefits.

5 Conclusions Smart luminescent packaging is an emerging form of intelligent packaging that combines interactivity, adaptability, and information processing. It offers personalized and customized services, protecting goods while enhancing the consumer experience. This article provides a comprehensive overview of its concept, components, key technologies, application fields, and future prospects. By integrating innovative technologies and materials, smart luminescent packaging enriches product packaging and holds potential for logistics management and environmental sustainability. However, further exploration is needed to develop environmentally friendly and reliable business models for sustainable development. Acknowledgements. This work was sponsored by the “Chenguang Program” supported by Shanghai Education Development Foundation and Shanghai Municipal Education Commission (No. 20CGB07) and Shanghai Municipal Youth Teacher Training Support Program (ZZSPPC21002).

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10. Ganeson, K., Mouriya, G.K., Bhubalan, K.: Smart packaging − a pragmatic solution to approach sustainable food waste management. Food Packag. Shelf Life 36(1), 101044 (2023) 11. Siddiqui, J., Taheri, M., Alam, A.U.: Nanomaterials in smart packaging applications: a review. Small 18(1), e2101171 (2022) 12. Baig, N., Kammakakam, I., Falath, W.: Nanomaterials: a review of synthesis methods, properties, recent progress, and challenges. Mater. Adv. 2(6), 1821–1871 (2021) 13. Davidovic, B., Labus, A.: A smart home system based on sensor technology. Fact. Univ. – Ser.: Electron. Energet. 29(3), 451–460 (2016) 14. Xu, J., Gu, B., Tian, G.: Review of agricultural IoT technology. Artif. Intell. Agricult. 6(1), 10–22 (2022) 15. Kaur, S., Singh, P., Tripathi, V.: Recent trends in wireless and optical fiber communication. Glob. Transit. Proc. 3(1), 343–348 (2022) 16. Wu, H., Li, X., Deng, Y.: Deep learning-driven wireless communication for edge-cloud computing: opportunities and challenges. J. Cloud Comput. 9(1), 1–14 (2020) 17. Seo, J., Jeon, G., Jang, E.S.: Preparation and properties of poly(propylene carbonate) and nanosized ZnO composite films for packaging applications. J. Appl. Polym. Sci. 122(2), 1101–1108 (2011) 18. Sharma, D.K., Shukla, S., Sharma, K.K.: A review on ZnO: fundamental properties and applications. Mater. Today: Proc. 49(1), 3028–3035 (2022) 19. Zhuo, Y., Brgoch, J.: Opportunities for next-generation luminescent materials through artificial intelligence. J. Phys. Chem. Lett. 12(2), 764–772 (2021) 20. Ravaro, L.P., Zanoni, K.P.S., de Camargo, A.S.S.: Luminescent Copper(I) complexes as promising materials for the next generation of energy-saving OLED devices. Energy Rep. 6(1), 37–45 (2020) 21. Huang, Y., Hsiang, E.L., Deng, M.Y.: Mini-LED, Micro-LED and OLED displays: present status and future perspectives. Light Sci. Appl. 9(1), 105 (2020) 22. Cho, J., Park, J.H., Kim, J.K.: White light-emitting diodes: history, progress, and future. Laser Photon. Rev. 11(2), 1600147 (2017) 23. Zhang, J., Ye, H., Jin, Y.: Recent progress in near-infrared organic electroluminescent materials. Top. Curr. Chem. 380(1), 6 (2021) 24. Wang, Z., Xie, D., Zhang, F.: Controlling information duration on rewritable luminescent paper based on hybrid antimony (III) chloride/small-molecule absorbates. Sci. Adv. 6(48), eabc2181 (2020) 25. Xiang, H., Wang, R., Chen, J.: Research progress of full electroluminescent white lightemitting diodes based on a single emissive layer. Light Sci. Appl. 10(1), 206 (2021) 26. Yang, B., Ma, D., Zheng, E.: A self-rechargeable electrochromic battery based on electrodeposited polypyrrole film. Sol. Energy Mater. Sol. Cells 192(1), 1–7 (2019) 27. Yousefi, H., Su, H.M., Imani, S.M.: Intelligent food packaging: a review of smart sensing technologies for monitoring food quality. ACS Sens. 4(4), 808–821 (2019) 28. Martinez-Olmos, A., Fernandez-Salmeron, J., Lopez-Ruiz, N.: Screen printed flexible radiofrequency identification tag for oxygen monitoring. Anal. Chem. 85(22), 11098–11105 (2013) 29. Ghaani, M., Cozzolino, C.A., Castelli, G.: An overview of the intelligent packaging technologies in the food sector. Trends Food Sci. Technol. 51(1), 1–11 (2016) 30. Fuertes, G., Soto, I., Carrasco, R.: Intelligent packaging systems: sensors and nanosensors to monitor food quality and safety. J. Sens. 2016(1), 1–8 (2016) 31. Guo, Q., Zhang, X.: A review of mechanochromic polymers and composites: from material design strategy to advanced electronics application. Compos. B Eng. 227(1), 109434 (2021) 32. Liu, Y., He, K., Chen, G.: Nature-inspired structural materials for flexible electronic devices. Chem. Rev. 117(20), 12893–12941 (2017)

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Development of an Anti-counterfeiting and Traceability System for Goods Based on RFID Tags Yongzhao Yang, Peng Liu(B) , Zhongrun Lv, Yujuan Yao, and Minying Zhou School of Printing Packaging and Digital Media, Xi’an University of Technology, Xi’an, Shaanxi, China [email protected]

Abstract. To enhance the anti-counterfeiting and traceability of goods, this paper has designed an anti-counterfeiting and traceability system based on RFID tags. This system uses RFID tags as the unique identifier for products and achieves full lifecycle traceability and monitoring of product information through cloud platform technology. The online system is developed using a front-end and backend separation approach, with hardware components implemented using STM32 and R2000, among other technologies. Through the integration of these technologies, the system provides functionalities such as user registration and login, input and storage of product information, RFID tag reading and writing, as well as the display and query of traceability results. This system effectively elevates the level of product anti-counterfeiting and traceability, safeguards consumer rights, efficiently accomplishes product traceability and anti-counterfeiting, and holds significant practical value and prospects for promotion. It plays an important role in advancing the industry’s technological and managerial standards. Keywords: RFID technology · Internet of things · Product traceability · Management and monitoring

1 Introduction RFID technology has a foundation in product traceability, but significant breakthroughs and widespread adoption are still pending [1]. Researchers abroad, like Liu et al., have developed RFID-based supply chain management tools for retrieving and storing IoT device and tagged product information [2]. Kumar et al. designed an RFID and Bluetooth monitoring system for remote tracking of materials and products [3]. In China, Deng and his team created a product logistics traceability system using Wireless Sensor Networks (WSN) [4]. Challenges persist in product traceability, including limited parameters collected by RFID systems, mainly used in product storage and transportation, making it challenging to reflect crop growth environments. Data collection by government, companies, and logistics firms via various platforms creates integration difficulties, hindering comprehensive traceability across the industry chain. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 198–204, 2024. https://doi.org/10.1007/978-981-99-9955-2_25

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To address these issues, a smart product traceability system is proposed, integrating cloud platforms and RFID tags. By attaching RFID tags to goods, the system collects and stores unique product identifiers, facilitating real-time data exchange with cloud platforms. This offers technical support for comprehensive product traceability, empowering consumers to understand production, logistics, and raw material sources, enhancing transparency and credibility [5]. This paper will delve into traceability technologies, system architecture, and functional implementation to showcase the advantages and application potential of an RFID-based anti-counterfeiting and traceability system.

2 Analysis of Key Technologies The counterfeit prevention and traceability system is a technology developed to combat counterfeit goods and protect consumer rights. Traditional technologies like barcodes and QR codes, used in many product traceability systems for decades, have limitations [6]. RFID tags offer advantages. They don’t need direct contact for reading, allowing remote, efficient data retrieval. They have greater storage capacity, accommodating more information. Multiple RFID tags can be read at once, speeding up large-scale traceability. Moreover, RFID tags are more durable and resistant to forgery compared to barcodes and QR codes. These benefits make RFID technology an advanced and practical choice, driving the development of counterfeit prevention and traceability systems. This paper’s system also relies on RFID technology.

3 System Architecture Design 3.1 Overall Structure Design The overall architecture of the anti-counterfeiting and traceability system for goods is highly complex, involving various aspects of product production, processing, warehousing, transportation, and distribution [7]. The anti-counterfeiting traceability system based on RFID tags designed in this paper adopts a five-layer structure. The various layers collaborate with each other to ultimately achieve system functionality, and Fig. 1 is the schematic diagram of the overall system structure design. The Perception Layer is the foundational layer of the system structure, consisting of three parts: fixed RFID readers/writers, handheld RFID readers/writers, and BeiDou locators. Its function is to read and write RFID tags and obtain current logistics coordinates through hardware devices. The Data Layer primarily provides data support to the system, storing the full-process information of product traceability. In addition, the Application Layer is responsible for all the system’s application functions, while the Encryption Layer and Access Layer handle data encryption and system access functions.

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Fig. 1. Overall structure diagram of the counterfeit prevention and traceability system

3.2 Overall Software Design Overall software design includes frontend design and backend design. The frontend is responsible for the presentation and interaction of the user interface, while the backend is responsible for handling business logic and data management. Figure 2 shows the overall software design process for the system.

Fig. 2. Overall software design framework of the system

The front-end is developed using the Vue framework and the Element UI component library to achieve a user-friendly interface and provide a good user experience. The front-end design includes user registration and login interfaces, personnel management interfaces, warehouse and goods management interfaces, traceability result display interfaces, and operation record management interfaces. The back-end is developed using the Spring Boot framework and the MyBatis-Plus persistence framework to implement the system’s business logic and data management.

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The back-end design includes functionalities such as storing product information, storing personnel information, storing operation records, and storing warehousing and logistics information. 3.3 Overall Hardware Design The hardware design focuses on addressing the communication between RFID readers/writers, MCU processors, and the traceability system. The main hardware components of the system include the STM32 processor, R2000 RF chip, antennas, power supply. Figure 3 presents the overall hardware design framework of the system.

Fig. 3. Overall hardware design framework of the system

The RFID reader/writer, consisting of the R2000 RF chip and antenna, reads tags within its range. It sends the tag data to the MCU processor via a serial port. The MCU processor parses and processes the data, then uploads it to the traceability system via WiFi, USB, or 485 communication methods. The system stores the data in MySQL database tables. This hardware setup enables precise RFID tag reading, interaction with the backend system, and facilitates product traceability and anti-counterfeiting. 3.4 Database Design A well-designed database can improve system performance and data integrity [8]. For this system, MySQL, a relational database, is chosen as the backend database. MySQL has excellent performance and reliability, performs well in handling large amounts of data and complex queries, and has a wide range of applications and community support [9]. Based on the system requirements and functionalities, the main database tables used are: User table, Goods table, Trace table, Record table, Produce table, Process table, Storage table, Distribute table, Category table, and Location table. Figure 4 provides a detailed description of the attributes of the database tables and the relationships between them.

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Fig. 4. Physical entity-relationship diagram of database tables

4 System Function Implementation 4.1 User Registration and Login Module The user registration and login module provide the functionality for user registration and login to ensure system security and identity verification. Users register an account by filling in their personal information, including username and password. The system will encrypt the user’s password using a hash algorithm. During login, users need to provide their registered credentials, and the system will verify their identity and grant access permissions. This module is designed to protect user privacy and ensure system security. 4.2 RFID Tag Read/Write Module The RFID tag reader/writer module is the information acquisition unit of the traceability module, consisting of an RFID directional antenna, RF transceiver module, and core control unit. During the production process, RFID tags are attached to goods and crucial information is written into the tags. The system reads the information on the RFID tags using a reader, ensuring the unique identification of goods and the accuracy of traceability data. 4.3 Information Input and Storage Module The information input and storage module allow users to input product information through a frontend interface and store it in the database. Users enter comprehensive process information for each stage of production, processing, warehouse transportation,

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and distribution. They submit this information to the backend service. The backend service validates and encrypts the received data and stores the product information in the database. Through the three modules mentioned above, both the hardware and software components of the anti-counterfeiting traceability system for products have been successfully established, with the implementation results depicted in Fig. 5.

Fig. 5. Traceability system implementation results figure

5 Conclusions This paper presents a counterfeit traceability system for goods based on RFID tags, which achieves full lifecycle traceability and monitoring of product information. The development of this system has made a certain contribution to the technological research in the field of counterfeit traceability of goods, and it better protects the legitimate rights and interests of consumers. Further research can be conducted to explore the system’s functional improvement, performance optimization, and scalability to meet the needs of different industries and products.

References 1. Ning, P.: Design of a smart agriculture information traceability system based on LoRa and RFID. Yangtze River Inf. Commun. (2022) 2. Liu, Y., Wang, H., Wang, J., et al.: Enterprise-Oriented IoT name service for agricultural product supply chain management. Int. J. Distrib. Sens. Netw. (2015) 3. Kumar, S G., Prince, S., Shankar, B M.: Smart tracking and monitoring in supply chain systems using RFID and BLE. In: 2021 3rd International Conference on Signal Processing and Communication (ICPSC) (2021)

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4. Deng, M., Ge, Z., Xiong, Q., Wang, X.: Design of agricultural product logistics intelligent traceability system based on embedded linux. Chinese J. Agric. Mechanization (2016) 5. Mumtaz, N M B., Muneer, A.: Secure Identification, Traceability and Real-Time tracking of agricultural food supply during transportation using internet of things. IEEE ACCESS (2021) 6. Zhang, X., Zhang, L.: Design of Blockchain Traceability Scheme Based on Hierarchical Secure QR Code. Comput. Eng. Appl. (2022) 7. Zhu, X., Chang, W., Zhang, Y., et al: Research on traceability and warehouse management system based on RFID. China Storage Transp. (2023) 8. Wang, S.: Design and implementation of agricultural product traceability system based on the internet of things. (Master’s thesis). Nanjing Univ. Posts Telecommun. (2021) 9. Bartłomiej, W., Piotr, J., Mariusz, W.: Test platform for developing processes of autonomous identification in RFID systems with proximity-range read/write devices. Electronics (2023)

Intelligent Management System for Logistics and Storage of Chinese Medical Herbs Based on RFID Peiyuan Zhu, Gaimei Zhang(B) , Hui Liu, Xiaoli Song, Jiandong Lu, Jiazi Shi, Yonggang Yang, Baiqing Sun, and Jingjing Hu Beijing Institute of Graphic Communication, Beijing, China [email protected]

Abstract. Objective In view of the unfavorable supervision of Chinese medical herbs in the logistics process due to product pollution and deterioration, it is necessary to develop the intellectualized and digitalized management system in the logistics transportation and storage process. Methods Based on internet of things technology and radio frequency identification technology(RFID), a logistics information of Chinese herbal medicine packaging tracing system was designed and developed, which realized the warehousing management, real-time positioning, temperature and humidity, and real-time update of data, and the system was applied to real-time environmental monitoring. Results The information traceability system of product packaging can facilitate the user to obtain information to improve the management level. The accuracy of the system measurement was verified by comparing with the values of temperature and humidity meters. Conclusions It provides a new idea for establishing a reliable and practical environment tracking and information traceable logistics system of Chinese herbal medicine, which is conducive to the protection of Chinese herbal medicine during storage and logistics. Keywords: Chinese medical herbs · Packaging · RFID Information traceability · Logistic

1 Introduction The sustained economic growth has enriched people’s demand for goods, services and information circulation, and also brought about the double growth of logistics demand [1]. The storage of Chinese medical herbs has strict requirements on environmental temperature and humidity, whether the temperature and humidity are too high or too low can affect the effectiveness of the drug, and even worsen. It is particularly important to monitor the environment of Chinese medical herbs, but there is a lack of warehousing and logistics management system. By studying the weak points of Chinese medical herbs in logistics distribution and storage, a tracking system for the logistics and storage process of Chinese medical herbs © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 205–211, 2024. https://doi.org/10.1007/978-981-99-9955-2_26

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was designed. Based on the global positioning system (GPS) [2], radio frequency identification (RFID) technology [3–5], temperature and humidity and wireless communication technology comprehensively, a logistics and warehousing information traceability system was built for traditional Chinese herbs packaging to achieve the collection and traceability of information for Chinese medical herbs products during logistics and warehousing processes.

2 Design of Intelligent Management System for Logistics and Storage of Chinese Medical Herbs 2.1 Demand Analysis of Intelligent Management System for Logistics and Storage of Chinese Medical Herbs At present, two-dimensional code labels are used by most of the logistics warehousing, which requires the staff to scan in turn, which is time-consuming and laborious. RFID electronic labels affixed to product packaging can carry out an intelligent inventory management system, thus reducing labor costs, and enabling the basic information of consumers to be mastered through information collection and big data analysis. Intelligent management system for logistics and storage based on RFID technology can effectively improve the traceability and query of Chinese medical herbs logistics. Various information of Chinese medical herbs is input into the management system, the complicated process of manual information verification of Chinese medical herbs logistics can be simplified. This can improve the efficiency of Chinese herbal medicine logistics. The functions of Chinese medical herbs source traceability, process monitoring and risk traceability can be realized 6. Chinese medical herbs are easily affected by temperature and humidity, especially humidity. If temperature and humidity are too high or too low, the quality of Chinese medical herbs will be influenced. Herein, the environment inquiry of products in the logistics process can be be effectively provided by the packaging information tracing system of Chinese medical herbs based on information acquisition technology. 2.2 Overall Design of Information Tracing System Based on the domestic Chinese medical herbs logistics market and environmental conditions, various functions required for product packaging information traceability were analyzed. As shown in Fig. 1, global positioning technology, Internet of Things RFID technology, temperature and humidity detection technology, acceleration detection technology and wireless communication technology are comprehensively adopted to build an intelligent system with real-time update of product status and real-time monitoring during transportation from product storage, loading, transportation and arrival, etc. The whole system architecture mainly includes the infrastructure layer, the application service layer, the interface access layer and the terminal display layer. Firstly, the hardware resources are mainly provided by the infrastructure layer to ensure the normal operation of the system. Secondly, service communication and management functions are provided by the application service layer, facilitating system deployment and management. Next, the interface access layer contains the entry logic for each service, which

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Fig. 1. Overall architecture of intelligent management of logistics and warehousing

can be accessed via HTTP, Socket, Web service, and so on. Finally, different display interfaces for different terminal devices are provided by the terminal display layer, which is beneficial for users to operate and manage the system. 2.3 Choice of Hardware Device In order to provide fast, efficient, stable, continuous and smooth operating environment, ultra-high frequency RFID tags are used as product labels, dth11 module (temperature measurement range is from -20°C to + 60°C, accuracy is ± 2°C; Humidity range is from 5%RH to 95%RH, accuracy is ± 5%RH) is used as humidity sensor in this system. Additionally, L76X GPS Module GNSS is used as GPS(GPS L1(1575.42MHz)).

3 Software Design of Product Packaging Information Tracing System for Chinese Medical Herbs During the transportation and circulation of Chinese medical herbs, the environmental parameters such as temperature and humidity will be changed. Based on Chinese medical herbs logistics, different usage modules are developed for users to realize effective management and information traceability. 3.1 Key Circulation Information of System Software The circulation links of Chinese medical herbs mainly include transportation links, storage links, loading and unloading links, packaging and processing links, etc., the information of each link is shown in Fig. 2. With the sharing of information on Chinese herbal medicines, consumers can access the logistics process of Chinese herbal medicines through the public service network improving the consumer experience and contributing to the expansion of sales volume [7, 8].

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Fig. 2. Information display diagram of each link

3.2 Function of Each Module of the System As shown in Fig. 3, according to the basic functions of the system, the software module is divided into RFID module, information acquisition module, system server module. Each function contains several sub-function modules, respectively.

Fig. 3. System function structure diagram

The information management module is mainly used for the basic information of Chinese medical herbs, including warehouse status, return and exchange situation and inventory management. The information traceability service can provide information query and traceability of the whole process of Chinese medicinal materials from warehousing management to transportation and sales to the destination of the goods. System device data synchronization mainly comes from RFID device information and information collection module, and it is necessary to ensure the coupling between RFID device, background database and information collection module. System management is only open to the administrator, mainly to add operation information to the system.

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4 Realization of Chinese Medicinal Materials Information Tracing System 4.1 RFID Handheld Function The main steps of RFID in logistics warehouse include: RFID tags are affixed to provide electronic marks for inventory goods, the smart packaging products with the logo are entered through the RFID sensor and the goods are placed in the designated warehouse according to the need, goods outbound management is done according to the needs of the product, the information traceability of warehousing goods has been achieved. The login and system of the RFID handheld is shown in Fig. 4.

(a) the login page (b) the main page of the system (c) the inventory management interface Fig. 4. Diagram of landing and system

4.2 Client Logs into the System with the Main Interface As shown in Fig. 5, the device was connected and run. After successfully logging in and entering the system, the function button in the left column can be used to add or delete different module information, as well as information traceability. The status of the order can also be queried.

Fig. 5. Order Inquiry Page

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The temperature and humidity information received by the system is shown in Fig. 6. In the system, temperature and humidity information of different dates can be viewed by adjusting the time to realize the traceability of temperature and humidity information.

Fig. 6. Temperature and humidity detection page

5 Conclusions RFID radio frequency identification technology has great technical advantages compared with bar code, two-dimensional code and other identification technologies. It is superior to over other identification technologies in terms of data transmission efficiency, data acquisition speed and data identification range. Moreover, logistics efficiency and traceability can be improved when applied to the logistics of high value-added goods in Chinese medical herbs. Acknowledgement. This work was supported by the Key Research Project of Beijing Institute of Graphic and Communication (Ed202104, Eb202201) and Key Lab of Intelligent and Green Flexographic Printing (ZBKT201810).

References 1. Hua, Y.: Innovation mode of cost management in modern logistics enterprises. China Market 12, 170–171 (2019) 2. Di, J.: Anti-collision algorithm in rfid packaging system. Packaging Engineering 39(01), 1–5 (2018) 3. Landaluce, H., Arjona, L., Perallos, A., et al.: A review of IoT sensing applications and challenges using RFID and wireless sensor networks. Sensors 20(9), 2495 (2020) 4. Casella, G., Bigliardi, B., Bottani, E.: The evolution of RFID technology in the logistics field: a review. Procedia Computer Science 200, 1582–1592 (2022)

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5. Chambers, T., Pearson, A.L., Kawachi, I., et al.: Kids in space: Measuring children’s residential neighborhoods and other destinations using activity space GPS and wearable camera data. Soc Sci Med Sci Med 193, 41–50 (2017). https://doi.org/10.1016/j.socscimed.2017.09.046 6. Kour, R., Karim, R., Parida, A., et al.: Applications of radio frequency identification (RFID) technology with eMaintenance cloud for railway system. Int. J. Syst. Assur. Eng. Manag.Manag. 5(1), 99–106 (2014) 7. Bo, Z., Dan, Z., Li-Jun, M., Lei, C.: Application of radio frequency identification (RFID) ownership transfer protocol on tracing of Chinese herbal-trace. Trans CSAE, 32(2): 309–314 (2016) 8. Lei, W., Gui-feng, W., Zi-duan, D.: Research on logistics management of chinese medical herbs based on sharing. Logistics Eng. Ring Manag. 43(06), 129–131 (2021)

Research on Anthocyanin-Based Indicator Labels and the Freshness Preservation Applications Yiyang Chen, Hui Liu(B) , Dan Yang, Yabo Fu, and Jiazi Shi School of Printing and Packaging Engineer, Beijing Institute of Graphic Communication, Beijing, China [email protected]

Abstract. To summarize the research and progress in the preparation of anthocyanin indicator labels and their application in food freshness monitoring. Relevant domestic and international literature is reviewed and organized, and different research results are summarized and compared. The factors influencing the performance of anthocyanins and the principle of pH-responsive color change are reviewed. The preparation methods and performance influencing mechanisms of composite films, and their research progress in food preservation applications are outlined. Anthocyanins have antioxidant, antibacterial, and pH-responsive properties for food freshness monitoring applications. The intermolecular forces between the components of the indicator label, such as hydrogen bonding and other effects on the properties of the label such as mechanical strength have a significant impact. The anthocyanin indication label has good application effect in the field of food freshness indication, and the research on antioxidant, antimicrobial activity and intelligence of color indication needs further depth, and the future development should not be underestimated. Keywords: Food Packaging · Anthocyanins · Natural Polymers · Indicator Label

1 Research Background Food spoilage is a major concern for consumers when purchasing goods, and smart packaging that can monitor the spoilage of the food inside in real time has become a hot research topic. Anthocyanin (CA)-based pH indication labels are gradually becoming a research component for many researchers to achieve visual color change for intuitive monitoring [1]. In addition, the safety of food packaging is also a focus of consumer concern [2], materials of natural origin have become more widely used in food packaging [3].

© The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 212–218, 2024. https://doi.org/10.1007/978-981-99-9955-2_27

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CA are non-toxic flavonoids with antibacterial and antioxidant activities [4]. In order to apply anthocyanins’ ability to change color in different pH environments to food packaging, natural polymers were selected as CA-bearing substances [5], some studies have used purple sweet potato anthocyanin as an indicator material to make antimicrobial films [6]. And such safety indication labels were mostly used for the spoilage of cow’s milk drinks and meat. In summary, the article will study the factors influencing the performance of CA, the compound preparation method, and the natural polymer pH colorimetric label based on CA, respectively.

2 Properties of Different Types of Anthocyanins CA is poor stable and can be affected by co-colorants, pH environment, and temperature [7], and color changes occur through chemical reactions, and hydroxyl or methoxy groups contained in the CA structure reduce the stability of CA in solution [8]. Studies have shown that CA stability can be improved by the addition of co-colorants, such as metal ions. The color development of CA in dragon fruit peel is enhanced when K+ and Mg2+ are added in appropriate amounts, while Fe2+ and Pb2+ reduce their antioxidant properties and stability [9]. Most CA are more stable under acidic conditions. Violeta et al. [10] found that CA appear red at pH 1–4 due to the presence of flavonoids cations; at pH 4–6, methanolic pseudo bases deprotonate and hydrate and become lighter in color; when pH increases to 7–11, the flavonoids cations deprotonate, generating quinone bases and the solution is blue-purple; at pH ≥ 12 the solution appears yellow. CA indicator labels can change color in response to changes in pH when meat spoilage releases TVB-N which increases alkalinity. CA are affected by temperature, the higher the temperature the less stable, Fu et al. [11] found that anthocyanins (CTAE) extracted from butterfly pea flowers are highly tolerant in acidic and alkaline environments, with a decrease in CTAE stability with increasing temperature and higher thermal stability at pH 7.

3 Compositing of Anthocyanins with Natural Polymers By adding CA to natural polymer film-forming substrates, the molecules are linked through intermolecular interactions to form a molecular network structure, and the compounding principle is shown in Fig. 1 [12]. Natural polymers and CA are compounded to form a film in the most dominant way of casting a film, the steps are shown in Fig. 2 [13].Besides, cellulose-based labels could also be made by methods such as screen printing [14]; acrylonitrile-based labels could also be prepared by electrostatic spinning [15].

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Fig. 1. Film lamination preparation principle

Fig. 2. Diagram of composite film casting into film

4 Application Study of Different Natural Polymer-Based Anthocyanin Indicator Labels CA complex with natural polymer macromolecules mainly through intermolecular interactions such as electrostatic, hydrogen bonding and van der Waals forces [12]. The nature of the natural polymer itself can significantly affect the response properties of CA [16], and CA can improve the mechanical properties by increasing the cohesion of the polymer matrix when combined with natural polymers [17]. The following section will explore the issues of color change indication, property changes and application feasibility of natural polymer-based CA films. 4.1 Anthocyanin Composited with Chitosan (CS) CS has good film-forming properties, is non-toxic and antibacterial [18], and is easily soluble at low pH values. The addition of polyvinyl alcohol (PVA) improves the water resistance of the film; the addition of essential oils and other substances improves the antibacterial and antioxidant properties of the film. Relevant studies are shown in Table 1. 4.2 Anthocyanin Composited with Cellulose Cellulose is a huge resource and insoluble in water, dilute acids and bases at room temperature [23]. The addition of certain natural substances can improve the antimicrobial properties of the films, in addition, nanocellulose has higher barrier properties and good hydrophobic properties. Relevant studies are shown in Table 2.

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Table 1. Chitosan-based anthocyanin indicator labels Material

Film color change

Application

Impacted performance

References

Light green; Light yellow

Fish; Milk

Thermal stability (TS); Elongation at break (EB)

[19]

Pink

Blue

Shrimp

Light stability

[20]

Eggplant CA; Red Laponite®; CS

Purple

Yellow

Beef

TS; EB; Water vapor permeability (WVP)

[21]

Oregano essential oil (OEO); Black rice CA; CS

Purple

Blue; Yellow

Pork

Antioxidation; Antibacterial; WVP

[22]

Acid

Neutral

Basic

Pink; Purple

Green

CS; PVA; CA Red

Purple tomato CA; CS

Pink

Table 2. Cellulose-based anthocyanin indicator labels Material

Film color change Acid

Application

Impacted performance

References

Neutral

Basic

Ethylcellulos; Red Castor oil; CA

Light pink

Green

Pork

Thickness; EB; Hydrophobicity

[24]

Cellulose; Purple sweet potato CA; OEO

Red; Pink; Brown

Light brown

Purple; Green; Yellow

/

Crystallinity; Light Transmittance (LT); TS; EB

[25]

Cellulose; Rose hips CA

Red

Magenta

Purple; Green

Chicken

TS; Hydrophobicity

[23]

4.3 Anthocyanins Composited with Starch Starch is a sustainable, low-cost polymer that is degradable and regenerative. The shelf life can be extended by adding antioxidant and antibacterial substances [26]; the addition of PVA improves the mechanical strength of the film. Relevant studies are shown in Table 3.

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Material

Film color change

Application

Impacted performance

References

Green

Fish

Moisture content(MC); Water solubility (WS); WVP

[27]

Purple

Blue-Green; Yellow

Fish

LT; MC; EB; Antioxidation

[28]

Light pink

Yellow

Fish

TS; MC; WVP

[29]

Acid

Neutral

Basic

Pink

Pink-Purple

Lycium CA; Pink Starch; PVA CA; Starch

Curcumin; CA; Starch; PVA

Pink

4.4 Anthocyanins Composited with Other Natural Polymers CA can also be compounded with other natural polymers to form films to prepare CA indicator labels, and related studies are shown in Table 4. Food packaging also gradually tends to be intelligent and associated with smart devices. Fang et al. [14] dissolved red kale CA, CMCS/OSA in silica sol and integrated them into APP using BP neural network. Table 4. Other natural polymer-based anthocyanin indicator labels Material

Film color change

Application

Impacted performance

References

Green

/

Antioxidation; WVP; EB; TS

[30]

Deep red-purple

Olive; Yellow

Seafood

Antioxidation; TS; EB; WVP; LT

[31]

Blue-Grey

Cyan

Shrimp

WS

[32]

Acid

Neutral

Basic

Butterfly pea CA; Gelatin

Purple

Blue

CA; CS; Arginine-modified CS; Gelatin

Red-Purple

Starch; CS; LCA

Pink; Light purple

5 Summary and Outlook CA are compounded with natural polymers such as chitosan through molecular interactions to form films for monitoring the freshness of food. The stability of CA needs to be considered in the subsequent research to ensure the problem of color appearance of the indicator label under different temperatures and acidity, including the color rendering and color gamut changes, to ensure the convenience and accuracy of the indication in the practical application of food packaging. Such pH colorimetric indicator labels will

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develop in the direction of active degradable and intelligent films [33], and will be more and more widely used in the field of food packaging such as meat. Acknowledgements. This project is supported by the doctoral initiation fund from Beijing Institute of Graphic Communication (27170123017) and the school level project from Beijing Institute of Graphic Communication (Ea202307).

References 1. Yin, W., Qiu, C., Ji, H., et al.: Recent advances in biomolecule-based films and coatings for active and smart food packaging applications. Food Biosci. 52, 102378 (2023) 2. Yan, M.R., Hsieh, S., Ricacho, N.: Innovative food packaging, food quality and safety, and consumer perspectives. Processes 10(4), 747 (2022) 3. Behling, R., Valange, S., Chatel, G.: Heterogeneous catalytic oxidation for lignin valorization into valuable chemicals: what results? What limitations? What trends? Green Chem. 18(7), 1839–1854 (2016) 4. Alam, A., Islam, P., Subhan, N., et al.: Potential health benefits of anthocyanins in oxidative stress related disorders. Phytochem. Rev. 20(4), 705–749 (2021) 5. Khademi, F., Taheri, R.A., Yousefi, A.A., et al.: Are chitosan natural polymers suitable as adjuvant/delivery system for anti-tuberculosis vaccines? Microb. Pathog. 121, 218–223 (2018) 6. Pang, G., Zhou, C., Zhu, X., Chen, L., Guo, X., Kang, T.: Colorimetric indicator films developed by incorporating anthocyanins into chitosan-based matrices. J. Food Safety (2023) 7. Azman, E.M., Yusof, N., Chatzifragkou, A., et al.: Stability enhancement of anthocyanins from blackcurrant (ribes nigrum l.) pomace through intermolecular copigmentation. Molecules 27(17), 5489 (2022) 8. Raki´c, V., Rinnan, Å., Polak, T., et al.: PH-induced structural forms of cyanidin and cyanidin 3-O-β-glucopyranoside. Dyes Pigm. 165, 71–80 (2019) 9. Chen, C.C., Lin, C., Chen, M.H., et al.: Stability and quality of anthocyanin in purple sweet potato extracts. Foods 8(9), 393 (2019) 10. Raki´c, V., Poklar, U.N.: Influence of pH on color variation and stability of cyanidin and cyanidin 3- O-β-glucopyranoside in aqueous solution. CyTA - Journal of Food 19(1), 174–182 (2021) 11. Fu, X., Wu, Q., Wang, J., et al.: Spectral characteristic, storage stability and antioxidant properties of anthocyanin extracts from flowers of butterfly pea (Clitoria ternatea L.). Molecules 26(22), 7000 (2021) 12. Qiao, S.H., Wang, Q., et al.: Application progress of anthocyanins in food quality indication. Packag. Eng. 43(17), 49–58 (2022) 13. Lu, Y., Li, C., Wu, Y.: Preparation of dimer acid-based polyamide film by solution casting method and its properties optimization. J. Polym. Res. 28(3), 68 (2021) 14. Fang, S., Guan, Z., Su, C., et al.: Accurate fish-freshness prediction label based on red cabbage anthocyanins. Food Control 138, 109018 (2022) 15. He, H., Song, Y., Li, M., et al.: A novel anthocyanin electrospun film by caffeic acid copigmentation for real-time fish freshness monitoring. Anal. Methods 15(2), 228–239 (2023) 16. Kossyvaki, D., Contardi, M., Athanassiou, A., et al.: Colorimetric Indicators based on anthocyanin polymer composites: a review. Polymers 14(19), 4129 (2022) 17. Azman, N.H., Khairul, W.M., Sarbon, N.M.: A comprehensive review on biocompatible film sensor containing natural extract: active/intelligent food packaging. Food Control 141, 109189 (2022)

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18. Zhao, Y., An, J., Su, H., et al.: Antimicrobial food packaging integrating polysaccharide-based substrates with green antimicrobial agents: a sustainable path. Food Res. Int. 155, 111096 (2022) 19. Li, Y., Wu, K., Wang, B., et al.: Colorimetric indicator based on purple tomato anthocyanins and chitosan for application in intelligent packaging. Int. J. Biol. Macromol. 174, 370–376 (2021) 20. Merz, B., Capello, C., Leandro, G.C., et al.: A novel colorimetric indicator film based on chitosan, polyvinyl alcohol and anthocyanins from jambolan (syzygium cumini) fruit for monitoring shrimp freshness. Int. J. Biol. Macromol. 153, 625–632 (2022) 21. Capello, C., Leandro, G.C., Gagliardi, T.R., et al.: Intelligent Films from chitosan and biohybrids based on anthocyanins and laponite®: physicochemical properties and food packaging applications. J. Polym. Environ. 29(12), 3988–3999 (2021) 22. Hao, Y., Kang, J., Guo, X., et al.: PH-responsive chitosan-based film containing oregano essential oil and black rice bran anthocyanin for preserving pork and monitoring freshness. Food Chem. 403, 134393 (2023) 23. Boonsiriwit, A., Itkor, P., Sirieawphikul, C., et al.: Characterization of natural anthocyanin indicator based on cellulose bio-composite film for monitoring the freshness of chicken tenderloin. Molecules 27(9), 2752 (2022) 24. Wang, X., Zhai, X., Zou, X., et al.: Novel hydrophobic colorimetric films based on ethylcellulose/castor oil/anthocyanins for pork freshness monitoring. LWT 164, 113631 (2022) 25. Chen, S., Wu, M., Lu, P., et al.: Development of pH indicator and antimicrobial cellulose nanofibre packaging film based on purple sweet potato anthocyanin and oregano essential oil. Int. J. Biol. Macromol. 149, 271–280 (2020) 26. Liu, D., Zhao, P., Chen, J., et al.: Recent advances and applications in starch for intelligent active food packaging: a review. Foods 11(18), 2879 (2022) 27. Chen, H., Zhang, M., Bhandari, B., et al.: Novel pH-sensitive films containing curcumin and anthocyanins to monitor fish freshness. Food Hydrocolloids 100, 105438 (2020) 28. Qin, Y., Yun, D., Xu, F., et al.: Smart packaging films based on starch/polyvinyl alcohol and Lycium ruthenicum anthocyanins-loaded nano-complexes: functionality, stability and application. Food Hydrocolloids 119, 106850 (2021) 29. Naghdi, S., Rezaei, M., Abdollahi, M.: A starch-based pH-sensing and ammonia detector film containing betacyanin of paperflower for application in intelligent packaging of fish. Int. J. Biol. Macromol. 191, 161–170 (2021) 30. Rawdkuen, S., Faseha, A., Benjakul, S., et al.: Application of anthocyanin as a color indicator in gelatin films. Food Biosci. 36, 100603 (2020) 31. Bakouri, H., Ziane, A., Guemra, K.: Development of multifunctional packaging films based on arginine-modified chitosan/gelatin matrix and betacyanins from weed amaranth (A. hybridus). Int. J. Biol. Macromolecul. 230, 123181(2023) 32. Li, B., Bao, Y., Li, J., et al.: A sub-freshness monitoring chitosan/starch-based colorimetric film for improving color recognition accuracy via controlling the pH value of the film-forming solution. Food Chem. 388, 132975 (2022) 33. Moshood, T.D., Nawanir, G., Mahmud, F., et al.: Sustainability of biodegradable plastics: new problem or solution to solve the global plastic pollution? Curr. Res. Green Sustain. Chem. 5, 100273 (2022)

Experimental Study on Food Delivery Boxes Utilizing Phase Change Materials for Thermal Energy Storage Shubao Zhou(B) Department of Printing and Packaging Engineering, Shanghai Publishing and Printing College, Shanghai, China [email protected]

Abstract. The temperature of food and the consumer experience in short-distance food delivery are closely linked. Insufficient temperatures upon arrival diminish consumer satisfaction. Research focuses on enhancing thermal insulation of delivery containers to slow temperature decrease during transportation. Phase change energy storage materials, capable of releasing or absorbing heat during phase transition, find wide application in energy storage, recovery, and battery thermal management. In the food industry, phase change materials are commonly used for cold chain transportation and storage. Selecting suitable materials maintains ambient temperature within delivery boxes, slowing temperature reduction. This study utilized paraffin with a phase transition range of 51–54 °C to fabricate a heat storage bag. Temperature monitoring and comparison with scenarios without the bag were conducted. Results demonstrate the bag’s effectiveness in reducing temperature decline during transportation. Keywords: Phase Change Material · Food Delivery · Hot beverage

1 Introduction The temperature of food and the consumer experience are closely intertwined in the process of short-distance food delivery. If hot beverages or food arrive at their destination with temperatures below the desired range, it will diminish the consumer experience and satisfaction. To address this issue, existing research primarily focuses on enhancing the thermal insulation performance of delivery bags or containers [1], aiming to slow down the temperature decrease of hot food or beverages during transportation. Phase change energy storage materials, capable of releasing or absorbing a significant amount of heat during phase transition [2, 3], are commonly employed in various fields such as energy storage engineering [4], energy recovery [5, 6], and battery thermal management [7, 8]. In the field of food delivery, phase change materials are frequently utilized for cold chain transportation and storage [9–11]. Selecting phase change materials suitable for the temperature of hot beverages or food can help maintain the ambient temperature within the delivery box at an appropriate range, thereby slowing down the temperature reduction of hot beverages or food. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 219–224, 2024. https://doi.org/10.1007/978-981-99-9955-2_28

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In this study, paraffin with a phase transition temperature ranging from 51 °C to 56 °C was employed to fabricate a heat storage bag. When in its liquid state, the paraffin was placed inside the delivery box together with the hot beverages, simulating the temperature conditions experienced by hot beverages during food delivery. Temperature monitoring was conducted to track the variations in temperature. Finally, the results were compared with those obtained from scenarios without the heat storage bag.

2 Experimental Method As shown in Fig. 1, the left diagram represents the frontal view, while the right diagram represents the lateral view. Hot water is placed inside the food delivery thermal box to simulate the actual transportation scenario of hot beverages. Figure 1 Five thermocouples are positioned in the box, with one measuring the internal temperature of the hot beverage, and the remaining four used to measure the ambient temperature of the box. The specific locations of the five thermocouples are indicated in Fig. 1 and Fig. 2. The internal dimensions of the thermal box are 44cm × 32cm × 30cm, and this type of thermal box is commonly used for the delivery of hot beverages such as coffee. The hot water container used is a paper coffee cup, filled with 400ml of hot water at a temperature of 63°C. The experiment was conducted in two trials, with the first trial conducted without the placement of the paraffin heat storage bag, and the second trial conducted with the placement of the paraffin heat storage bag. The paraffin heat storage bags contain 200 ml of liquid paraffin with an initial temperature of 60 °C, and the phase change temperature range of the paraffin is between 51 °C and 56 °C. After the start of the experiment, the computer records the temperature measurements from the thermocouples every two seconds. Each trial of the experiment lasts for 40 min, and the initial ambient temperature is set at 27 °C.

Fig. 1. Experimental setup (front view)

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Fig. 2. Experimental setup (end view)

3 Results and Discussions 3.1 Results Without PCM The variations in water and ambient temperature inside the food delivery box are shown in Fig. 2, when there is no paraffin heat storage bag. From Fig. 2, it can be observed that the ambient temperature inside the box gradually increases at the beginning of the experiment. At around 700 s, the ambient Fig. 3 temperature reaches its peak and then starts to decrease. On the other hand, the water temperature shows a gradual decrease trend from the start of the experiment, reaching a final temperature of 49.7 °C.

Fig. 3. Results without PCM

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3.2 Results with PCM The variations in water and ambient temperature inside the food delivery box with the presence of a paraffin heat storage bag are shown in Fig. 3. It can be observed that, similar to the case without the paraffin heat storage bag, the ambient temperature Fig. 4 inside the box gradually increases at the beginning of the experiment. Again, at around 700 s, the ambient temperature reaches its peak and then starts to decrease.

Fig. 4. Results with PCM

Regarding the water temperature, it also shows a gradual decrease trend from the start of the experiment, with a final temperature of 51.5°C. However, the temperature of the paraffin heat storage bag starts to decrease from its initial temperature of 60 °C. At around 500 s, the temperature stabilizes at around 55°, indicating the phase change of the paraffin. Due to the presence of latent heat during the phase transition, the temperature decrease of the paraffin is slow. At the end of the experiment, the temperature of the paraffin reaches 55.4 °C. 3.3 Comparison Figure 4 Illustrates the comparison of water temperature and paraffin heat storage bag temperature between the two experimental trials. In both trials, the trend of water temperature change is similar. However, when the paraffin Fig. 5 heat storage bag is present, the final temperature of the hot water is 1.8 °C higher compared to the trial without the paraffin heat storage bag. This clearly demonstrates the effective role of the paraffin heat storage bag in delaying the decrease in water temperature during the experiment.

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Fig. 5. Comparison of results

4 Conclusions The utilization of the paraffin heat storage bag effectively slows down the decrease in hot water temperature within the food delivery box, resulting in a temperature difference of 1.8 °C after 40 min. During short-distance transportation of hot beverages or food items, delivery personnel can carry the heat storage bag to the sales location for heating. Once the bag reaches a liquid state, it can be placed together with the food or hot beverages inside the food delivery box for transportation, and it can be reused repeatedly.

References 1. Song, H.Y., Cheng, X.X., Chu, L.: Effect of density and ambient temperature on coefficient of thermal conductivity of heat-insulated EPS and PU materials for food packaging. Appl. Mech. Mater. 469, 152–155 (2013). https://doi.org/10.4028/www.scientific.net/AMM.469.152 2. Diaconu, B.M., Cruceru, M., Anghelescu, L.: A critical review on heat transfer enhancement techniques in latent heat storage systems based on phase change materials. Passive and active techniques, system designs and optimization. J. Energy Storage 61, 106830 (2023). https:// doi.org/10.1016/j.est.2023.106830 3. Liu, Y., Zheng, R., Li, J.: High latent heat phase change materials (PCMs) with low melting temperature for thermal management and storage of electronic devices and power batteries: Critical review. Renew. Sustain. Energ. Rev. 168, 112783 (2022) 4. Chen, Y., et al.: Waste sugarcane skin-based composite phase change material for thermal energy storage and solar energy utilization. Mater. Lett. 342, 134320 (2023). https://doi.org/ 10.1016/j.matlet.2023.134320 5. Öztop, H.F., Co¸sanay, H., Biswas, N., et al.: Thermal energy storage via waste heat from finned heater by using different phase change materials in a closed space. J. Energy Storage. 70, 108002 (2023) 6. Nardin, G., Meneghetti, A., Dal Magro, F., et al.: PCM-based energy recovery from electric arc furnaces. Appl. Energy 136, 947–955 (2014) 7. Ni, R., Zhang, D., Wang, R., et al.: Prevention and suppression effects of phase change material on thermal runaway in batteries. Case Stud. Therm. Eng. 48, 103160 (2023)

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8. Luo, J., et al.: Battery thermal management systems (BTMs) based on phase change material (PCM): a comprehensive review. Chem. Eng. J. 430, 132741 (2022). https://doi.org/10.1016/ j.cej.2021.132741 9. Gin, B., Farid, M.M.: The use of PCM panels to improve storage condition of frozen food. J. Food Eng. 100(2), 372–376 (2010) 10. Meng, B., Zhang, X., Hua, W., et al.: Development and application of phase change material in fresh e-commerce cold chain logistics: a review. J. Energy Storage. 55, 105373 (2022) 11. Oró, E., Graciade, A., Cabeza, L.F.: Active phase change material package for thermal protection of ice cream containers. Int. J. Refrig.Refrig 36(1), 102–109 (2013)

Design and Application of Moiré Stripe Packaging Under Interactive Mechanism Chenchen Long(B) , Li Zhou, Yan Wang, Junyan Sun, Baoying Lin, and Liangzhe Chen(B) School of Electronic Information Engineering, Jingchu University of Technology, Jingmen 448000, China [email protected], [email protected]

Abstract. In order to broaden the boundary of commodity packaging, give packaging more functions, establish the emotional connection between consumers and packaging, and enhance product attraction. Through questionnaire survey and data survey, this paper analyzes the necessity of interactive performance of product packaging for consumers. This paper uses literature research and image analysis to explore the interactive generation mechanism of moiré fringe packaging from the theoretical level and the practical level. The results show that consumers prefer moiré stripe product packaging with interactive performance, mainly due to the dynamic effects of moiré stripes, which are manifested in psychological gestalt psychology, physiological afterglow effect, and the displacement of the subject person. At the application level, integrating moiré stripes into packaging can break away from electronic media, achieve mutual transformation between “static” and “dynamic”, control the state and behavior of “things” by people, achieve interaction among people, things and events, enhance product competitiveness, and is expected to be widely used in packaging design. Keywords: Interactive mechanism · Moiré fringe · Packaging design · Packaging bag · Packaging box

1 Introduction In recent years, with the continuous improvement of social living standards, people’s living ideas and consumption patterns have changed, and they begin to pay more attention to their spiritual and emotional needs. In this context, consumer groups also have higher requirements for product appearance and multiple functions when choosing products. In commodity sales, good packaging can effectively enhance consumers’ purchase desire, stimulate consumers to realize a second purchase, and can also fully interpret and summarize the brand culture of products and enhance the influence of enterprises. At present, under the environment of homogenized product competition, there are still some problems urgently to be solved in the packaging and design of the commodity in our country: (1) excessive packaging, low practicality and low use efficiency. (2) Lack of environmental protection. (3) Packaging information is not communicated clearly, © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 225–234, 2024. https://doi.org/10.1007/978-981-99-9955-2_29

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which cannot improve consumer satisfaction and affect their user experience. (4) Lack of humanistic consciousness and neglect of consumer emotional experience [1]. According to data research, consumers’ willingness to participate in contact and interaction with commodity packaging has gradually increased, and the multiple functions of packaging have been increasingly valued. Packaging is not only the acceptor and protector of products, but also the communicator and interlocutor of emotional and behavioural interaction with consumers. As a special dynamic form, moiré fringe can express its different dynamic sense through different material media and realize the human-producthuman mutual conversion mechanism. Therefore, moiré fringe as the leading interactive packaging is more and more favoured by designers.

2 Research Status Through the survey of 100 consumers from Hubei, Guangxi, Guizhou, Shenzhen, Hainan and other different cities, the age range of 10–50 years old, the survey data are shown in the table below. Consumers of different ages and regions prefer interactive product packaging when choosing similar products (Table 1). Table 1. Product packaging preferences research Problem

Option

You wish to purchase the packaging of Highlight the name of the main text the product Highlight the product graphics mainly With playability, interactive performance Other In the process of choosing products, Whether the packaging design of the what purchasing factors will you take product is in line with their favourite into account when similar products are After-sales service of products of the same quality? Advertising/branding of a product Product display effect What do you think a good package should have?

Percentage 2.22% 31.11% 62.22% 4.44% 77.78% 73.33% 44.44% 31.11%

Embody the humanized, interactive and 82.22% interesting functional design of the brand The uniqueness of the modelling structure

51.11%

Simple, fashionable and generous

64.44% (continued)

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Table 1. (continued) Problem

Option

What type of packaging do you prefer? Strong and secure

Percentage 64.44%

User experience first

64.44%

Easy to store and carry

82.22%

Environmental sustainability

46.67%

If the product packaging is well designed, will it increase your willingness to buy?

Correct

93.33%

Can interactive packaging attract your attention and enhance your desire to consume?

Correct

88.89%

Deny

11.11%

Deny

6.67%

3 Interactive Generation Mechanism of Moiré Stripe Packaging 3.1 Interactive Effects Based on Gestalt Psychology The application of moiré stripe elements in packaging can generate dynamic interactive effects, including the psychological and physiological factors of the viewer. The special composition of objects creates a unique personality in the originally static image. The viewer’s optic nerve is stimulated, which is then transmitted to various parts of the body through brain nerve reactions, ultimately forming a dynamic impression [2].

Fig. 1. Dynamic interaction experiment of moiré fringe

To more intuitively illustrate this viewpoint, the author conducted relevant experimental research, as shown in Fig. 1. Decompose the dynamics of a flying bird into 6 frames, with the number of frames equal to the number of gratings, and there is a fixed formula for the width and gap of a single grating to correspond to the number of frames produced, i.e. (grating width + gap width)/gap width = number of frames produced, gap width × (n-1) gratings. During this process, a strip-shaped arrangement area and a black large square area will be formed. The black square area is the area where the gratings do not completely overlap, and it is also the area where the gratings overlap with the

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background image. Repeat the above operation to finally complete the grating assembly. When processing the base image, it is necessary to match the order of the raster and frame, and then cut to obtain the keyframe shape. Finally, open all keyframe graphics to obtain the underlying keyframe graphics. Stack the raster planes on the bottom keyframe layer, pan to the right, and the interweaving area will appear as a fluttering bird. The more frames we need to explain here, the smoother and more diverse the dynamics. When the raster is moved, the keyframe image at the bottom automatically fills the blank area of each frame, and the position below each raster belongs to the blank area of the keyframe, which is complementary to each other, Therefore, each raster movement will quickly hide the keyframe image and give way to the next image. The lack of graphics is automatically supplemented through human gestalt psychology, making it a continuous and complete whole [3]. The movement of the “gestalt” line segments creates a sense of movement, and ultimately allows us to see dynamic moiré changes on the packaging carrier of static patterns. 3.2 Interaction Effect Based on Afterglow Effect To explore the viewer’s perception of Moiré stripe packaging, it is necessary to consider its perception mode of dynamic interaction from the physiological level, which is the physiological basis of visual perception of works with “dynamic interaction”. The afterglow effect is the most common kind of movement sensation based on the characteristics of human eyeballs. There are two explanations for this. First, the direction and target of movement are misjudged by the stimulation of the environment. The second is the phenomenon of continuous motion that can be perceived from a single element that is at rest [4]. When the processed keyframes are assembled into a static picture and the raster on the upper layer of the picture is moved, due to the afterglow effect of human eyes, although the first image imaged on the retina disappears under the action of light, the continuous appearance of multiple similar images can produce continuous dynamic visual phenomena and form interactive animation. 3.3 Interaction Effect Based on Viewer Displacement The interactive effect caused by viewer displacement is a way of “driving” the dynamic effect of the screen by relying on changes in the orientation of the viewer’s head, the way and speed of leg movement, and changes in body movements. Such images do not feel dynamic when the viewer is stationary. Only when the person’s vision or position changes, can the changes in the image be observed. When the human line of sight is in a parallel state, the ciliary muscle in the eye is completely relaxed, and the field of vision is 6 m away [5], the collection and rough outline of most objects are usually seen at this time. In this case, the perception of shape is partial or incomplete [6]. In the process of walking, the visual field of the viewer’s left eye and right eye superimposed is 124°, the best visual field of one eye is within the range of 60°, and the best rotation area of both eyes is [30°, 60°]. With the left-right movement of the visual Angle, the visual field seen is constantly expanded, and the horizontal visual Angle of both eyes can reach 188° [7], as shown in Fig. 2.

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Fig. 2. Binocular field of view

4 Overall Scheme Design of Moiré Stripe Packaging 4.1 Case Study As pictured Fig. 3 shown, the envelope of Nankai University’s admission letter for 2020 is in the form of Moiré hollow stripes, showing the visual effect of alternating sun and moon in the building, as shown in Fig. 3 (left). There is also the mooncake packaging in the picture on the right, which grasps the “interactive dynamic” pulse in chronological order. By using color and moiré principle to fully display the ups and downs of the moon through the action of pulling out, the characteristics and laws of each stage, as well as the coordination of the relationships between them, perfectly interprets the concept mentioned in The Book of Changes: “From the sun to the moon, from the moon to the sun, from the moon to the sun, from the sun to the moon, and from the sun to the moon, and from the moon, from the sun to the moon, there is a bright life” [8].

Fig. 3. Nankai University Admission and moon cake packaging design

For the above two packages, the author draws corresponding images according to the viewing angle state of the viewer watching the moiré stripe packaging, as shown in Fig. 4. When consumers enter shopping malls, supermarkets and other shopping places, the field of view will change during the process of walking, and it is in a dynamic state, which covers the restricted and unrestricted eye movement range, as well as the

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unrestricted eye movement caused by head rotation [9]. When walking, people’s eye activity is in a fast and active state, and they will not stay at a certain fixation point. In addition, the packaging adopts the form of moiré gratinga, and the stripe spacing of the double-sided fence is interleaved with the image, which echoes the field of view of the human eye during the movement of the viewer, forming the overlap of the left and right field of view, and generating a dynamic fixation point area. The place where the fence overlaps in the image is actually the area where the viewing field of the left and right eyes overlaps when the viewer walks around. Since the extraocular muscle of the eyeball can regulate the movement of the eye, the viewing field of both eyes and the viewing field of one eye maintains a certain Angle relationship with the object, so the viewer will have the visual centre, the edge range of the viewing Angle and the best viewing field when watching [10].

Fig. 4. Human eye view-when viewing the moiré stripe packaging

4.2 Practical Exploration In this practice, the author used the traditional Chinese painting “Suzhou’s Golden Age” as the prototype and selected two scenes for animation production (Fig. 5):

Fig. 5. Flow chart

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The painting “The Prosperity of Suzhou” originally depicts people’s livelihood. In the selection of scenes, the author takes the temporary rest of the busy citizens as the blueprint and uses the flying posture of birds, the swaying trees in the wind, and the rising sun as dynamic objects. The continuous actions are decomposed and depicted in the form of each frame. First, a “normal” complete scene is drawn and then connected. After processing with moiré grating, the above dynamic objects are cut into a picture, this also completes the keyframes of the animation, as long as the upper layer of the image is covered with a raster, dynamic changes can be generated. The specific image transformation process can refer to Table 2: Table 2. Schematic diagram of the grating conversion process

Prototype redesign once

Secondary barrier-type conversion

Prototype redesign once

Secondary barrier-type conversion

Character transformation

The moiré grating is placed on the upper layer of the keyframe bottom image, and the characters will continuously stretch and recycle the fishing net, as shown in Fig. 6. In this practical creation, the scenes in traditional famous paintings are flattened and interesting. Through the geometric structure of characters’ faces, the combination of lowpurity colors, and the embellishment of scenes, traditional art is unfolded in a modern way, achieving a transformation from “static” to “dynamic”. The traditional scene of the redesign is applied in packaging design, transforming two-dimensional flat patterns into multi-dimensional three-dimensional patterns. When the packaging box is opened, the hollow moiré grating of the outer packaging begins to move, and the internal images also change motion, improving consumers’ subjective sense of participation, establishing emotional links between consumers and brands, and achieving a human product human interaction mechanism (Table 3).

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Color network model

Number

01

03

07

Color lump

CMYK C:77 M:63 Y:20 K:00 C:65 M:31 Y:40 K:00 C:31 Y:31 M:62 K:00

Number

08

09

10

Color lump

CMYK C:70 M:08 Y:67 K:00 C:65 M:04 Y:84 K:00 C:91 Y:43 M:91 K:08

Fig. 6. Effect of the themed packaging box

Fig. 7. (Left) Leather inner bag (Center) Leather outer bag, (Right) Theme abstract bag effect reflected by the combination of inner and outer bags

In addition to exploring the concrete patterns of moiré stripes, the author also designed bags based on their abstract patterns, mainly using the “MOIRE” font. Figure 7 (left) shows the pattern design of the leather inner bag. The author has undergone three different transformations of the “MOIRE” pattern, which has been rasterized to form the pattern of the inner bag. When the inner and outer bags are combined, the pattern on the bag will change according to the wearer’s posture, and single or multiple patterns will appear at different time points. Sometimes, fuzzy pattern backgrounds will also appear, highlighting the broken or complete “MOIRE” font. In Fig. 8, the leather bag designed

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by the author is for autumn and winter. When the inner and outer bags are combined, a scrolling subtitle state will appear. These dynamic effects interpret the theme and also reflect the wearable dynamic feeling.

Fig. 8. (Lower left): leather inner cover (Lower right): leather outer cover (Top): The themed abstract bag effect reflected by the combination of inner and outer bags

5 Conclusions In recent years, there have been significant breakthroughs in the development of Application themes and communication media based on the principle of moiré animation, especially in the fields of display windows, packaging, and space, achieving diversification of themes and material innovation. However, rational thinking is still needed for the color and composition of moiré stripes, as well as the diversity of graphic operations, whether in the field of packaging, architecture, space, or other fields. In the field of product, we cannot blindly pursue cool and dynamic effects, only focusing on the visual form of the surface and ignoring the connotation and meaning behind the design. We should use visual modelling language to awaken people’s emotional cognition and social consciousness. The combination of moiré stripes and product packaging, on the one hand, can transform the communication mode from one-way to two-way or even multi-directional; on the other hand, people are the main body, and the shape and movement state of the visual object is actively controlled and manipulated by the viewer, narrowing the psychological distance between people and art, and also easier to obtain a sense of Cultural identity and belonging. This packaging design method meets the desire of viewers to change the way information is exchanged, allowing them to communicate and influence the changes in information with the packaging content promptly. It truly considers “people” as the main body of the design, thereby driving the overall healthy development of the packaging industry. Acknowledgements. This work was funded by the Outstanding Young and Middle-Aged Scientific and Technological Innovation Team of Colleges and Universities in Hubei Province (No. S202311336001).

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References 1. Xu, H.: Based on intelligent packaging interaction Psychological research on emotional experience of design. Beauty Times, 51–53 (2021) 2. Invernizzi, A., Halbertsma, H.N.: rTMS treatment of visual hallucinations using a connectivity-based targeting method - a case study. Brain Stimulation 1622–1624 (2019) 3. Woo, H.K., Lee, S., Jeong, Y.H.: Research on a new vision test chart measuring visual and spatial sense of moiré fringes. J. Korean Ophthalmic Opt. Soc. (2010) 4. Gombrich, E.H.: The Image and The Eye: A Reexamination of the Psychology of Picture Representation. Guangxi Fine Arts Publishing House, Guangxi (2016) 5. Eeball structure theory. https://www.youlai.cn/ask/B38855msF8S.html.2020/2/10 6. Arnheim, R.: Visual Thinking - Aesthetic Intuition Psychology, pp. 45–46. Sichuan People’s Publishing House, Chengdu (2016) 7. Xu, Y., Guan, H.: Virtual reality display model based on human vision principle. Comput. Appl. 35(10), 2939–2340 (2015) 8. Ruan, Y.: Notes on the Thirteen Classics, pp. 87–88. Zhonghua Book Company, Beijing (1980) 9. Ichi, Y.J.: Theoretical study of the properties of X-ray diffraction moiré fringes. II. Illustration of angularly integrated moiré images. Acta Crystallographica. Sect. A, Found. Adv., 610–623 (2019) 10. Zhang,Y., Zhao, Y., Fan, Q.: .Research on multimodal interactive packaging design for visually impaired users. Hunan Packag., 160–161 (2023)

Simulation Study of Foam Starch Based Material Buffer Model Based on Abaqus Qin Lei1 , Yin Zhu1 , Xuanhui Ouyang1 , Hang Qiu1 , Wu Liu2 , and Yunfei Zhong1(B) 1 School of Packaging and Materials Engineering, Hunan University of Technology,

Hunan, China [email protected] 2 United Creation Packaging Solutions, Nanjing, Jiangsu, China [email protected]

Abstract. Foam starch-based cushioning materials have great application prospects in transport packaging design. In this paper, we hope to understand the mechanical properties of foam starch based through experiments, and to make simulation hypothesis analysis to determine whether the mechanical properties of the foam are in line with Hyperfoam mechanical model. In this paper, the mechanical properties of this starch-based foam material under compression are analyzed and verified with the Hyperfoam module of ABAQUS. The experimental results show that the displacement pressure curve obtained by the electronic universal testing machine is different from the stress-strain curve obtained by the simulation software. Therefore, the starch-based foam material does not conform to the mechanical properties of Hyperfoam. Keywords: Computer simulation technology · Foam starch based material · Buffer performance

1 Introduction Plastics are widely used in daily life and production, but because of its advantages of easy access and light weight, it not only brings convenience to people’s life, but also causes many permanent hazards to our environment [1]. With the mass production and use of plastic products in China, the production of waste plastics has also increased sharply. “White pollution” has become a prominent problem in our country’s environmental protection at this stage [2]. Therefore, the use of degradable plastics instead of nondegradable plastics has become our research goal at this stage, in line with the “double carbon policy” and in line with the national development strategy. While recycling old plastics [3], we should also study new biodegradable and renewable plastics to alleviate the increasingly severe environmental and energy crisis [4]. Biodegradation is one of the important methods to solve white pollution at present. It is very difficult to avoid the outflow of plastic products to the environment. Therefore, in order to reduce the environmental load, the outflow of plastic products should be biodegradable plastics as much as possible [5]. At present, many biodegradable foamed © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 235–243, 2024. https://doi.org/10.1007/978-981-99-9955-2_30

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plastic products with good performance have been developed at home and abroad, such as biodegradable polyester and protein, and biotechnology has been used in plastic synthesis [6]. However, these products are expensive and difficult to be widely used in various fields. After years of research, many experts have turned their attention to starch. Starch is the second largest biomass on the earth. It is not only rich in resources and easy to obtain raw materials, but also cheap (0.25 to 0.60 dollars per kilogram, lower than ordinary petrochemical products). It not only has perfect biodegradability, but also has many potential unused functional groups on its biological macromolecule chain. If it is applied to the foam industry, not only can the product have good environmental coordination, but also can obtain new application performance [7]. Starch based foam is a very important biodegradable material [8]. Compared with EPE [9], foam starch base has many advantages, such as good environmental protection and degradability, while taking into account the buffer performance. Many experts and scholars have made great research achievements in their respective fields [10, 11], but there are few simulation studies on foam starch based foaming materials in the market. In ABAQUS simulation software, the super foam model can better simulate the compression of models similar to EPE, and its contained Crusable foam foam model is suitable for the establishment of plastic material models. Solid materials will produce corresponding deformation in the corresponding stress direction after being stressed. From the beginning of deformation to the final failure of solid materials, it generally needs to go through two stages: elastic deformation and plastic deformation. Among the cushioning foam materials, some materials have low elasticity, for example, the elasticity of EPS is significantly smaller than that of other materials; The common pearl cotton cushioning material has good elasticity. Refering to the EPE simulation analysis [12], this paper are based on the hyperfoam model in Abaqus software to conduct simulation analysis under the dynamic impact of foam starch base, explore the mechanical properties of such foam starch base in the compression process, and compare and analyze whether the hyperfoam model in ABAQUS is suitable for the simulation of foam starch base.

2 Experimental Materials and Equipment The electronic universal testing machine uses an electronic device to accurately control, measure, display and record the load and the deformation of the test piece. The laboratory usually implements the compression test of the buffer material through the electronic universal testing machine to test the buffer performance of the buffer material. Figure 1 is a floor-door electronic universal testing machine manufactured by Shenzhen Xin Sansi Company, which was purchased by Hunan University of Technology Laboratory. The model number is CMT 4104. Its maximum compression force is 10 KN and its accuracy level is 0.5. The foamed starch-based test material purchased this time is a small cylinder. Because of its small volume, the results obtained by using a single material for the test will lead to a large experimental error. Also because of the softness of the paper, it has little effect on the compression test results. Therefore, this experiment is carried out by placing a certain number of materials into a paper cylinder with a diameter of 90 mm

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Fig. 1. Electronic universal material testing machine

and a height of 80 mm. As shown in Fig. 2, four groups of samples are divided into four groups for compression buffer test. The average density of foam starch-based materials can be measured without compression. Referring to the method of Static Compression Test Method for Buffer Materials for Packaging [13–15], the test buffer materials are compressed. The four groups of subjects are compressed quasi-static at a compression speed of 10 mm/min. The force-displacement image results are shown in Fig. 3.

Fig. 2. Experimental sample of foam starch based material

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Fig. 3. Compression test results of foam starch based materials

From the four control experiments, it can be seen that the force received by the subjects in the four groups is almost the same in the range of 0 mm to 6mm displacement, and then with the increase of vertical displacement, the reaction force of the subjects increases. However, due to the gap between the granules of starch-based materials and the compression of the internal space of the granules due to foaming, the starch-based materials show a certain buffer protection performance. We will process the data from four sets of experiments, because the strain calculated from the displacement of the universal testing machine is that the engineering stress is not real stress, and the true stress is calculated from the relationship between the engineering stress and the real stress in Eq. (1).   (1) εtrue = −ln 1 − εeng εtrue is true stress and εeng is engineering stress. The stress-strain diagram of the experimental phase is obtained as shown in Fig. 4.

Fig. 4. Experimental compression stress-strain results

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3 Selection and Fitting of the Constitutive Model of Starch Foam-Based Materials Ogden model is selected in this experiment, the main reason is that Ogden model has very obvious advantages. Firstly, this model is very applicable and widely used. I.J. SnchezArce points out that Ogden hyperelastic model can easily represent Neo-Hookean and Mooney-Rivlin models, making them universal [16]. Therefore, it can be used to study various types of hyperelastic constitutive relationships, and it is suitable for dealing with large deformation problems. The higher the order of Ogden model, the higher the accuracy. It is also well suited for describing the behavior of slightly compressed materials and can fit the data well even when the strain is large. In this experiment, the second-order Ogden model is used for compression: the Formula is:   N   2μi αi 1  −αi βi αi αi λ J + λ +λ − 3 + − 1 U (λ1 , λ2 , λ3 ) = 1 1 βi αi2 1 i=1

The stress-strain data obtained from compression experiments are fitted by least squares method, and the second-order formula parameters are obtained by fitting in MATLAB software: μ1 = 202670, μ2 = 29.999, α1 = 39011, α2 = 2.81547.

4 Establishment and Assembly of Finite Element Model 4.1 Establishment of 3D Modeling Ogden hyper-elastic foam model (Hyper foam model) has been widely used to characterize the superelastic deformation of elastomeric foam [17]. In order to study the accuracy of “super-elastic foam model” in the elastic phase of foam starch matrix materials under impact, the hyper-foam model commonly used in ABAQUS was also used to simulate the static pressure of foam starch matrix materials, and the simulation results were compared with the experimental results. A three-dimensional solid was established in ABAQUS, where the ground was set as a discrete rigid body stretched, and the foam starch-based material was set as a threedimensional deformable stretched solid with a base radius of 90 mm and a height of 80 mm. Because of the softness of the paper and it does not play a major supporting role in the compression process, we ignore the influence of the paper when setting the density. We use the volume and mass of the foam starch in the paper tube to calculate the material density of the simulation analysis. The density property of starch-based materials is 17.02 kg/m3 , Its essence is even. Set the fixing plate position below and the upper impact plate to apply pressure on. The specific relative position is shown in Fig. 5. 4.2 Establishment of Material Properties Based on the data obtained from the above experiments and the parameters related to the second-order Ogden model of the material calculated by fitting, the ABAQUS simulation experimental conditions are input, and the friction type between the upper plate and the material, the lower fixed plate and the material is established, and the friction coefficient is set to 0.3.

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Fig. 5. 3D Model drawing

4.3 Establishment of Boundary Conditions In the process of static compression, the direction in which the impact plate is subjected to force is limited, the load on the impact plate is limited to the downward direction, and the displacement in other directions is effectively controlled, so as to ensure the feasibility of the experiment and limit the displacement in all directions of the lower fixed plate. A common contact between the starch-based material and the upper and lower pressure plates is established to prevent the penetration and breakdown of the model units during the impact process, which prevents the experiment from proceeding. The contact type between the upper impact plate and the foam starch base and the lower fixing plate and the foam starch base is surface contact, and the contact type between the starch based material and the pressing plate is node contact. The compression condition is set to quasi-static compression, and the compression speed is designed to be 0.6m/s. Based on the experimental compression results, the same compression distance is controlled, so the simulation compression time is set to 0.1s, and the boundary condition is set here. 4.4 Grid Division To make the experimental results as accurate as possible, we set the approximate global size to 0.002m in size control and hexahedron structure for the starch-based material, where the cell type is set to Explicit dominance. After meshing, 82200 grid cells were successfully divided. Similarly, when meshing the upper impact plate and the lower fixed plate, based on the same considerations, we set the cell type to dominant, the global size control to

Fig. 6. Result of grid division

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0.008m, and the cell shape to the structure quadrilateral in this design. Finally, 784 grid cells were successfully divided. The meshing results are shown in Fig. 6.

5 Simulation Results and Analysis

Fig. 7. Force distribution cloud diagram

Fig. 8. Results of ABAQUS simulation experiment

After simulation analysis, the force cloud diagram is shown in the Fig. 7. From the force cloud diagram, we can see that the simulation analysis can simulate the compression performance of the material. In abaqus, we select a reference point on the model, and use the force of the point and the relevant parameters of the model to obtain the stressstrain curve during the compression process. The results are shown in the Fig. 8. As shown in Fig. 8, in the stage of relatively small strain, the change of stress is not obvious because there are gaps between the starch-based materials and the existence of internal bubbles formed by the foaming of starch-based materials. However, with the increase of strain, the stress of the starch-based foam also increases rapidly. The experimental law conforms to the stress characteristics of the buffer foam during compression. It is also verified that the material is suitable for use as cushioning packaging liner. By comparing the results of the experiment with those of the simulation in Fig. 9, The maximum stress in the simulation experiment is 121479 Pa and the maximum

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Fig. 9. Stress-strain contrast diagram of compression and simulation test

stress in the compression experiment is 79526 Pa. we can see that the stress-strain curve obtained by the experiment deviates significantly from the simulation data obtained by the corresponding parameters of hyperfoam high elastic foam model in ABAQUS. Xu Ya, Fu Zhiqiang et al. point out that after the engineering stress is corrected to true stress, the maximum error between displacement within 5 mm of the stress-strain simulation result and the experiment is only 2%, while the error increases gradually to 61% after the displacement is 5 mm [18]. In this experiment, a large error is formed when the strain is small, which proves that the sample is not suitable for simulation using hyperfoam model under this condition.

6 Conclusions Based on the mechanical properties of the high elastic foam model built in ABAQUS and the compression results of the starch foam based material on the electronic universal testing machine, the results of impact simulation analysis of the starch foam base have higher accuracy. The Hyper foam model was used to simulate the static compression process of foam starch base. The results of simulation and the experimental results have great errors. Although the selection of the experimental model may cause some errors, the comparison between the experimental results and the simulation shows that there is a big difference between the two models in the force characteristics, which indicates that the Hyper foam model is not suitable for simulating the static compression buffer process of such elastic foam materials as foam starch base. Acknowledgements. This research is supported by Natural Science Foundation of Hunan Province (No.2021JJ30218) and supported by Hunan Provincial College Student Innovation and Entrepreneurship Training Program (No. [2022]174-3609).

References 1. Liu, Y., et al.: Progress in the production of new materials from recycled waste plastics. New Chem. Mater. 37(5), 3–5 (2009)

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2. Ding, M., et al.: Current status and prospects of recycling and utilization of waste plastics in China. Compr. Utilizat. Resour. China (6), 36–39 (2004) 3. Yamin, S.: Status and development of recycling and utilization of waste plastics. Yunnan Chem. Ind. 2, 36–40 (2008) 4. Min, H., Wen, J.: Environmental crisis and clean energy. Environ. Sustain. Dev. 6, 49–50 (2007) 5. Huiguhao: Biodecomposition. Polym. Proc. 47(4), 2 (1998) 6. Huan, D., Shugui, C., Jialian, S.: Enzymatic synthesis and modification of biodegradable macromolecules. Chem. Bull. 3, 11–17 (1997) 7. Liu, F., Yu, J.: Application of starch in foam plastic products. Chem. Ind. Eng. (1), 43–48 (2000) 8. Wang, H.: Study on starch-based foam plastics. Tianjin University of Science and Technology (2004) 9. Guo, X., et al.: Research progress of polyethylene foaming materials. Petrochemical 44(2), 261–266 (2015) 10. Qiuli, W., Jianqing, W.: Chengpeifang: buffering properties of starch-based biodegradable foamed plastics. Packag. Eng. 2, 14–15 (2007) 11. Hongwu, W.: Research progress on extrusion foaming of starch-based biodegradable materials. Plast. Technol. 38(4), 96–99 (2010) 12. Lei, F., et al.: EPE shock simulation based on Abaqus low density foam model. Plast. Technol. 47(9), 89–94 (2019) 13. Guo, Y., Xu, W.: Packaging Test Technology. Chemical Industry Press, Beijing (2006) 14. GB/T 8168–2008, Static Compression Test Method for Buffer Materials for Packaging (2008) 15. Grand, A.: Packaging Engineering Experimental Tutorial. Printing Industry Press, Beijing (2012) 16. Snchez-Arce, I.J., Ramalho, L.D.C., Gonalves, D.C.: Hyperelasticity and the radial point interpolation method via the Ogden model. Eng. Anal. Boundary Elem. 145, 25–33 (2022) 17. Yan, S., et al.: Novel strategies for parameter fitting procedure of the Ogden hyperfoam model under shear condition. Eur. J. Mech. A. Solids 86, 36–47 (2020) 18. Xu, Y., et al.: Correction of true stress and strain data of thin film based on finite element method. Plast. Ind. 49(07), 144–147+116 (2021)

Drop-Impact Analysis of Liquid-Containing Beer Bottles by Finite Element Method Xiaoli Song, Chunxiu Zhang(B) , Jiacan Xu, Yuqi Yao, and Wenxiu Guo School of Printing & Packaging Engineering, Beijing Institute of Graphic Communication, Beijing, China [email protected]

Abstract. In order to improve the impact resistance of glass containers, this study utilized the finite element method to investigate the mechanical properties of liquid-containing glass beer with different drop mode. The results show that stress within the beer bottle is primarily concentrated at the bottle-ground contact point throughout the drop, creating a fracture once the stress surpasses the critical threshold. As the fracture forms, the stress continues to increase until it reaches its maximum, after which it progressively disperses throughout the entire bottle body. From research data, it was found that when θ is 30°, its maximum stress is 283.703 MPa, while θ are 0° and 90°, the stresses are 184.987 MPa and 116.583 MPa, respectively. Therefore, inclined drops generate greater stress impact onto the bottle, making it more vulnerable to damage compared to fully vertical / horizontal drops. Regardless of the drop mode, the point of maximum stress is always situated at the bottle-ground contact point, whereas the magnitude of maximum stress at the moment of fracture is not directly proportional to the different drop modes. Keywords: Finite element method · Drop · Mechanical Properties · Beer Bottle

1 Introduction Fall damage has always been a major concern during product distribution and consumption. Therefore, investigating the characteristics of products’ drop-impact dynamics holds great significance from an engineering standpoint. The extent of drop-impact damage is normally determined not only by the fragility, but also drop height and drop mode, while conventional research approaches predominantly rely on theoretical analysis or experimental testing [1–3]. However, theoretical analyses tends to lack rigor and depth, which makes them unreliable for analyzing real-world products, while drop-test experiments are costly, time-consuming, high in control threshold, and limited in terms of quantifiable measurements, which makes outcomes expressible as a spatiotemporal continuum relatively challenging to acquire, as well as the mechanisms governing the structural responses and deformations amid drop impact very difficult to comprehensively showcase. In contrast, simulating the dynamics of drops using computer-aided tools not only sheds more light into the dynamic response of packaging components © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 244–252, 2024. https://doi.org/10.1007/978-981-99-9955-2_31

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under the influences of impacts and vibrations, but also yields invaluable data unobtainable via physical testing. These facilitate the analyses of the packaging’s impact strength, impact toughness, and other mechanical properties of critical components, which further open the path for determining the primary influencing factors that ensures packaging safety [4–6]. All of these translate to the set of rationales guiding the design of elastic elements and considerations for the buffering mode, minimizing the required number of experiments, significantly accelerating product development, and exhibiting substantial advantages, particularly so in its applicability in transport packaging. Against this backdrop, this study utilized the finite element method to investigate the mechanical properties of liquid-containing glass beer bottles as they dropped.

2 Finite Element Modeling for the Glass Beer Bottles and the Liquid 2.1 Finite Element Modeling for the Glass Beer Bottles The beer bottle simulation was run using ABAQUS over a multiple-step sequence, which includes component creation, material creation, section property definition and specification, assembly definition, analysis design, as well as boundary conditions and loading definition. The dimensions of the model were determined based on the outer shape of a 500ml beer bottle of China Resources’ Snow brand, as presented in Table 1. Table 1. Exterior Dimensions of the Beer Bottle (mm) Body Height

Cylinder Height

Neck Height

Cylinder Diameter

Neck Diameter

Body Thickness

Bottom Thickness

Body Curvature

30.223

176.856

143.633

64.000

13.340

2.000

5.885

45.000

For the finite element analysis (FEA), the bottle is transformed into a variable shellshaped three-dimensional model, as depicted in Fig. 1.

Fig. 1. Three-dimensional representation of the beer bottle

The material properties for the glass are defined as displayed in Table 2.

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Density (kg/m3 )

Elastic Modulus (MPa)

Poisson’s Ratio

2.53*103

80,000

0.253

In this study, the beer bottle is simulated to make an angle θ with the ground and undergo a dynamic response during a drop from height H. The ground is assumed to be a rigid body, as illustrated in Fig. 2.

Fig. 2. Assembly diagram of the beer bottle model

Due to the massive time increments required for simulating the motion of the beer bottle under the influence of gravity, the computational cost of this method is prohibitively high, not to mention that it is also prone to errors. Therefore, this study adopted an alternative simulation approach whereby the beer bottle underwent a free-fall at an assigned initial velocity, say, V (m/s) from a very close initial position off the ground, say, H (m), which meant that its downward impact velocity was also V (m/s), as indicated by Eq. 1.  (1) V = 2gH where g is 9.810 (m/s2 ). To ensure the accuracy of the analysis, a partitioning technique of mapped meshing using quadrilateral elements and S4R shell element was employed, as demonstrated in Fig. 3. The contact problem between the glass beer bottle and the ground amid the drop is classified as a non-linear problem. To address this, the computing was run with a dynamic/explicit integration algorithm created under the assumption that both the outer surfaces of the glass beer bottle and the ground are smooth and create no friction. 2.2 Finite Element Modeling for the Liquid In the FEA, the liquid substance is considered using the Eulerian rotation technique. The liquid model is constructed by rotating it in accordance with the shape of the bottle, as depicted in Fig. 4. Water, specifically defined with the material properties outlined in Table 3, was selected as the liquid.

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Fig. 3. Beer bottle model after meshing

Fig. 4. 3D Diagram of the Liquid Model

Table 3. Material properties of liquid Density (kg/m3 )

Speed of Sound (m/s)

Viscosity (Pa·s)

1.0*103

1,483

1

To ensure the accuracy of the computation, the model was meshed using hexahedral elements and S4R shell elements, as presented in Fig. 5.

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Fig. 5. Water model after meshing

3 Results and Analysis 3.1 Stress Distribution During Beer Bottle Drop Process When θ = 30° and H = 0.8 m, the stress distribution at different time intervals during the drop is as depicted in Fig. 6. To enhance the clarity of the beer bottle’s stress, the liquid component is concealed.

a

t=0.0001s

b

t=0.0004s

c

t

d

t=0.0020s

Fig. 6. Drop-impact Stress Distribution of the Beer Bottle when θ = 30°and H = 0.8m

Figure 6 shows that the ground impact concentrated the stress at the specific point of contact between the beer bottle body and the ground. As the drop progressed, the movement of the liquid inside the bottle led to an increase in and a dispersion of stress at this location. However, the primary stress-bearing areas remained to be the bottleground point of contact. Once the stress reached 326.829 MPa, the bottle ruptured,

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creating fractures at the bottle-ground point of contact. Furthermore, once the stress reached 570.942 MPa, it began to disseminate uniformly throughout the bottle body, with fragments predominantly concentrated at the contact point between the ground and the beer bottle. 3.2 Influence of Drop Mode on Stress To answer this, the height was kept constant at H = 0.5 m , before simulating the effects of altering the beer bottle’s drop mode to θ = 0°, θ = 30°, θ = 60°, and θ = 90°. Stress Distribution at the Moment of Impact. Figure 7 Depicts the Stress Distribution on the Beer Bottle, with the Liquid Hidden for Clarity.

a

θ=0

b

θ=30

c

θ=60

d

θ=90

Fig. 7. Stress Distribution at the Moment of Impact across Different Drop Modes

Figure 7 provides insights into how liquid content influences the stress. At θ = 0° and θ = 90°, the stress on the beer bottle was uniformly distributed at the wetted surface area within the bottle at the moment of impact. On the other hand, at θ = 30° and θ = 60°, stress predominantly concentrated at the vertical position relative to the bottle bottom-ground contact point. Stress Distribution Immediately Prior to Fracture Under Different Drop Modes. Again, the liquid is hidden herein for maximum clarity of the stress distribution on the beer bottle, as demonstrated in Fig. 8.

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a

θ=0°

b

θ=30°

c

θ=60°

d

θ=90°

Fig. 8. Stress distribution immediately prior to fracture under different drop modes

Using ABAQUS’ search-by-value option, the set of σmax right before the formation of fracture under different drop modes was acquired, and is presented in Table 4. Table 4. σmax immediately prior to fracture for different drop modes. θ/°

0°

30°

60°

90°

σ max /MPa

184.987

283.703

142.231

116.583

From Fig. 8 and Table 4, it can be observed that the liquid’s downward motion at θ = 0°, 30°, and 60° raised the lower-end stress at the bottle-ground contact point, leading to fracture after the specific stress thresholds were surpassed. At θ = 90°, the influence of liquid on the bottle’s bottom resulted in a transfer and gradual increase of stress distribution in that region, creating fracture after exceeding the stress threshold. Instantaneous Stress Distribution at σmax . Figure 9 Illustrates the Stress Subject to the Beer Bottle (Liquid not Shown) at the Point of Maximum Stress.

Drop-Impact Analysis of Liquid-Containing Beer Bottles

a

=0°

b

θ=30°

c

θ=60°

d

θ=90°

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Fig. 9. Instantaneous Drop-impact Stress Distribution within the Beer Bottle at σmax

Using ABAQUS’ search-by-value option, the σmax generated during the beer bottle’s drop at different heights was examined. The results are as presented in Table 5. Table 5. σmax during beer bottle drop at different heights. θ/°

0°

30°

60°

90°

σ max /MPa

314.703

626.667

542.336

398.607

It can be inferred from Fig. 9 and Table 5 that fracture propagated from the initial fracture point towards the direction of the bottle’s mouth. As the drop progressed the fracture area gradually expanded into the bottle’s body after certain maximum stresses were reached. Moreover, Fig. 7, 8, 9, Table 4, and Table 5 also suggest that inclined drops generate higher stress impacts relative to their fully horizontal and vertical alternatives, simultaneously making the bottle more damage-prone. The point of maximum stress Fig. 9 during the drop consistently emerged at the bottle-ground point of contact. Furthermore, the magnitudes of σ max did not exhibit a proportional relationship with θ across different drop modes.

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4 Conclusions The following conclusions were drawn through data processing and research analysis: Stress within the beer bottle is primarily concentrated at the bottle-ground contact point throughout the drop, creating a fracture once the stress surpasses the critical threshold. As the fracture forms, the stress continues to increase until it reaches its maximum, after which it progressively disperses throughout the entire bottle body. Inclined drops generate greater stress impact onto the bottle, making it more vulnerable to damage compared to fully vertical/horizontal drops. Regardless of the drop mode, the point of maximum stress is always situated at the bottle-ground contact point, whereas the magnitude of maximum stress at the moment of fracture is not directly proportional to the different drop modes. Acknowledgement. This work was supported by the Key Research Project of Beijing Institute of Graphic and Communication (No. Eb202201, Ed202221, Ec202206and Ed202104), the Beijing Natural Science Foundation (No. 2222055), Discipline construction of material science and engineering(No. 21090123007), The Ministry of Education Key Laboratory of Luminescence and Optical Information, Open project (No.KLLI0BJTUKF2204).

References 1. Kavermann, S.W., Bhattacharyya, D.: Experimental investigation of the static behaviour of a corrugated plywood sandwich core. Compos. Struct. 207, 836–844 (2019). https://doi.org/10. 1016/j.compstruct.2018.09.094 2. Zhong, C., Yang, Y., Zhou, L.: Research status and prospect of e-commerce logistics packaging. J. Packag. 12(05), 27–34 (2020) 3. Chao, M., Guang, L.: Drop Simulation analysis and optimization design of red wine package. Packag. Eng. 39(3), 38–42 (2018) 4. Shao-yun, Z., Huo, C., Fu-de, L.: Finite element analusis for dynamic response of cushioning system made out of honeycomb paperboard and foam. Journal of Vibration and Shock, 33(2), 52–54 (2014) 5. Pei-pei, C., et al.: Application of drop simulation based on solidworks. Packag. Eng. 35(13), 51–55 (2014) 6. Xue, L.: Finite element analysis of dynamic properties of expanded polyethylene cushion packaging system. Packag. Eng. 32(13), 11–13 (2011)

Design of Structural Parameters for Paper-Based Spherical Porous Materials and Its Influence on Static Cushioning Performance Xiaoli Song(B) , Gaimei Zhang, Jiandong Lu, Jiacan Xu, Yuqi Yao, and Xinyu Zhang School of Printing and Packaging Engineering, Beijing Institute of Graphic Communication, Beijing, China [email protected]

Abstract. In order to improve the cushioning performance of cushioning materials and reduce the use of materials, the structural parameter is designed and the static cushioning performance of Paper-based Spherical Porous Materials is analyzed in this paper. The cushioning coefficient and the stress-strain curve are investigated under the different structural parameters. The results show that the different structural parameters of the materials affect the static cushioning performance of such materials. The compression process can be divided into three stages: linear elasticity, yielding, and densification. As the pore size decreases, the yield value increases progressively, indicating an enhancement in the rigidity of the paper-based spherical porous materials and a reduction in cushioning effectiveness. Smaller pore sizes result in improved cushioning performance for paper-based spherical porous materials. Increasing the thickness enhances the cushioning performance of paper-based spherical porous materials. Keywords: Porous materials · Parameter design · Static Cushioning Performance

1 Introduction During transportation and handling, packaged products are susceptible to mechanical impacts, vibrations, and other forces. Inadequate packaging can easily result in product damage, leading to significant economic losses for customers [1–4]. Cushioning packaging materials can absorb the energy generated by impacts under mechanical stress, thus effectively protecting goods and preventing damage. Consequently, cushioning packaging materials have been extensively used in modern packaging practices for minimizing product damage during transportation and handling. Presently, materials such as expanded polyethylene (EPE), expanded polystyrene (EPS), and honeycomb cardboard are extensively employed for cushioning packaging [5, 6]. With the heavy consumption of paper-based cushioning materials for the purpose of environmental protection and effective protection, there is growing interest in studying their mechanical properties © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 253–258, 2024. https://doi.org/10.1007/978-981-99-9955-2_32

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and cushioning mechanisms [7, 8]. Enhancing the performance of paper-based cushioning packaging to its fullest potential and reducing packaging costs are pressing issues that need to be addressed. For paper-based porous materials, maximizing their performance necessitates attention to their pore structure design. This research focuses on the design of structural parameters for paper-based spherical porous materials and their influence on the mechanical properties of the materials.

2 Processing of Paper-Based Spherical Porous Materials 2.1 Design of Pore Shape for Paper-Based Spherical Porous Materials Figure 1 illustrates the schematic diagram of the pore shape for paper-based spherical porous materials, where R represents the radius of the spherical pore.

Fig. 1. Schematic diagram of the pass

2.2 Processing Techniques for Paper-Based Spherical Porous Materials Experimental Equipment: DHG constant-temperature drying oven by Shaoxing Supo Instrument Co., Ltd.; DEM-F600 humidifier by Deerma; 8002 paper cutter by Deli; plastic film; SHIMADZU AUW320 electronic analytical balance; glass rod; beaker; spherical pore-shaped mold. Experimental Materials: Core paper; LETU potato starch powder. Experimental Procedures: a) Cut the paper into the desired size. b) Place the moistened paper into the mold and press it to form the corrugations. After drying, apply adhesive to complete the bonding process. c) Place the core paper along with the mold into an electric heated constant temperature drying oven and dry it for 10 min. Then, bond the core papers together and continue drying to complete the fabrication of the test samples, as illustrated in Fig. 2.

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Fig. 2. Picture of a sample

3 Results and Analysis 3.1 Influence of Pore Size on the Mechanical Properties of Paper-Based Spherical Porous Materials A constant thickness of 50 mm for the experimental samples was maintained, and the pore size (R) was varied to 6 mm, 5 mm, 4 mm, 3 mm, and 2 mm, respectively. Static compression tests were conducted, and the stress-strain curves are depicted in Fig. 3.

Fig. 3. Stress–strain curves of paper-based spherical porous materials with different pore size

It can be observed from Fig. 3 that the compression process could be divided into three stages: linear elasticity, yielding, and densification. Although the shapes of the curves for different pore sizes of porous materials are generally similar, the yield values differ. Specifically, the yield values for paper-based spherical porous materials with pore sizes of 6 mm, 5 mm, 4 mm, 3 mm, and 2 mm are 4.693 MPa, 7.657 MPa, 11.023 MPa, 18.549 MPa, and 31.459 MPa, respectively. As the pore size decreases, the yield value gradually increases, indicating an increase in the rigidity of the paper-based spherical porous materials and a reduction in cushioning effectiveness. Based on the data from Fig. 3, the cushioning coefficient (C) was calculated, and a plot of the cushioning coefficient against strain was generated, as depicted in Fig. 4. As shown in Fig. 4, when the deformation of the paper-based spherical porous materials reaches approximately 50%, the material with a pore size of 2 mm exhibits the

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Fig. 4. Cushioning coefficient–strain curves of paper-based spherical porous materials with different pore size

smallest cushioning coefficient, which is 3.698. This indicates that this material is capable of absorbing the most energy and possesses the optimum cushioning performance. Moreover, as the pore size decreases, the cushioning performance of the paper-based spherical porous material improves. 3.2 Influence of Thickness on the Mechanical Properties of Paper-Based Spherical Porous Materials A constant pore size (R) of 5 mm was maintained for the experimental samples, and the thickness was varied to 50 mm, 40 mm, and 30 mm, respectively. Static compression tests were conducted, and the stress-strain curves are shown in Fig. 5. It can be observed from Fig. 6 that the curves for porous materials with different pore sizes have similar shapes, but the positions where yielding occurs vary. The yield values for paper-based spherical porous materials with thicknesses of 50 mm, 40 mm, and 30 mm are 7.999 MPa, 6.612 MPa, and 6.170 MPa, respectively. As the thickness of the experimental samples increases, the yield value gradually increases, indicating an increase in the rigidity of the paper-based spherical porous materials and a reduction in cushioning effectiveness.

Fig. 5. Stress–strain curves of Paper-based Spherical Porous Materials with different thickness

Based on the data from Fig. 5, the cushioning coefficient (C) was calculated, and a plot of the cushioning coefficient against strain was generated, as depicted in Fig. 6.

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Fig. 6. Cushioning coefficient–strain curves of Paper-based Spherical Porous Materials with different thickness

As shown in Fig. 6, when the deformation of the paper-based spherical porous materials reaches approximately 50%, the material with a thickness of 50mm exhibits the smallest cushioning coefficient, which is 4.81825. This indicates that this material is capable of absorbing the most energy and possesses the optimum cushioning performance. Moreover, as the thickness increases, the cushioning performance of the paper-based spherical porous material improves.

4 Conclusions The following conclusions were drawn through data processing and research analysis: • The compression process can be divided into three stages: linear elasticity, yielding, and densification. As the pore size decreases, the yield value increases progressively, indicating an enhancement in the rigidity of the paper-based spherical porous materials and a reduction in cushioning effectiveness. • Smaller pore sizes result in improved cushioning performance for paper-based spherical porous materials. • Increasing the thickness enhances the cushioning performance of paper-based spherical porous materials. Acknowledgement. This work was supported by the Key Research Project of Beijing Institute of Graphic and Communication (No. Eb202201, Ed202221, Ec202206and Ed202104), the Beijing Natural Science Foundation (No.2222055), Discipline construction of material science and engineering(No.21090123007), The Ministry of Education Key Laboratory of Luminescence and Optical Information, Open project (No.KLLI0BJTUKF2204).

References 1. Kavermann, S.W., Bhattacharyya, D.: Experimental investigation of the static behaviour of a corrugated plywood sandwich core. Compos. Struct. 9, 836–844 (2018)

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2. Wu, T.-T., Wu, J.-Z., Wang, H., Cai, J.-L.: Research progress on technology economy and environmental impact assessment of buffer packaging materials. Eng. Packing 42(9), 17–24 (2021) 3. Zhong, C., Yang, Y., Zhou, L.: Research status and prospect of e-commerce logistics packaging. J. Packaging 12(05), 27–34 (2020) 4. Measures for the management of mail express packaging. Gazette of the State Council of the People’s Republic of China, vol. 12, pp. 22–25 (2021) 5. Shen, Z., Chen, D., Luo, J.-J.: Simulation and analysis of dropping impact acceleration of polyethylene foam buffer system. Eng. Packing 37(19), 128–131 (2016) 6. Castigioni, A., Castellani, L.C.G., et al.: Relevant materials parameters in cushioning for eps foams. Colloids Surf., A 534(1), 71–77 (2017) 7. Kong, Z.: Research on the application of buffer packaging materials in the storage and transportation of agricultural products. Xinjiang Agric. Sci. Technol. 1, 15–16 (2018) 8. Singh, S., Gaikwad, K., Lee, M., et al.: Thermally buffered corrugated packaging for preserving the freshness of mushrooms. Food Eng. 216(1), 11–19 (2018)

Study on Innovative Packaging Design and Protection Performance of Fine Strawberries Xinyu Cui and Lijiang Huo(B) School of Light Industry and Chemical Engineering, Dalian Polytechnic University, Dalian, China [email protected]

Abstract. The sales of high-quality strawberries are mainly completed through e-commerce and physical stores. Packaging is an important technical link for its effective protection and promotion. This study takes high-quality strawberries as contents. Based on the needs of commercial logistics, innovative design of strawberry packaging was carried out for two different scenarios: e-commerce packaging and on-site packaging. They are all made of corrugated cardboard and adopt a heart shaped paper forming structure. Apply antibacterial coating inside the e-commerce packaging. Sealing the packaging before the start of ecommerce transportation can ensure the safety of the contents. Vertical impact drop and compressive strength testing experiments were conducted on the e-commerce packaging. Its average compressive strength is 945N, and after a drop of 800 mm, its appearance is intact, meeting the requirements of e-commerce logistics. On site packaging can compress the box blank into a flat shape, facilitating transportation to physical stores for opening and disposal by consumers. Keywords: E-commerce packaging · On-site packaging · Packaging design · Strawberry · Protective performance

1 Introduction Nowadays, the ecological fruit market requires both local on-site sales and long-distance delivery. At present, plastic materials are mainly used for transportation and retail packaging in the strawberry market. This traditional packaging has a single material, structure, and function, and is not environmentally friendly, which can no longer meet the new packaging and consumption needs of high-quality fresh fruit packaging under the national “dual carbon” background [1]. In response to the current situation of high-quality strawberry packaging, this article conducts research and development on e-commerce and on-site packaging design. E-commerce packaging design needs to meet the strength requirements of e-commerce packaging, have novel shapes and structures, not be maliciously opened, and be environmentally friendly; The main goals of on-site packaging innovation design and research are to make the packaging box easy to use, convenient for post-use disposal, novel in shape and structure, protect the contents, and be environmentally friendly. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 259–263, 2024. https://doi.org/10.1007/978-981-99-9955-2_33

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2 Innovative Packaging Design Strawberries resemble hearts, and there are also some festivals related to love during the fruiting period [2]. Therefore, the design theme of the high-quality strawberry packaging is set as the love theme - “berry” troubles. From the psychological perspective of the applicable customer group, the acceptance range of heart type is the widest; Considering the user experience of the customer group, a more convenient structure is adopted for opening and retrieving; From the perspective of environmental benefits, a paper formed packaging box can reduce resource loss and environmental impact. This article uses a maximum size of 35 mm × 35 mm × 45 mm high-quality strawberries are included as the contents. Design two types of gift box packaging and buffering structures for different applicable environments in e-commerce and on-site environments. 2.1 E-commerce Packaging Design The e-commerce packaging material is B-corrugated cardboard (250/220-125/1B). The inside of its packaging is coated layer by layer with 1% sodium alginate + 0.3% lemon essential oil + 2% pectin [3]. The lining material inside the box is selected as E-corrugated cardboard (200/180-100/1E). The structural design and size calculation results are shown in Fig. 1 (a) and Fig. 1(b), the effect is shown in Fig. 2. The outer box of e-commerce packaging is designed as a heart shaped tube shaped folding paper box with 24 strawberries inside, with a total weight of 0.5 kg.

Fig. 1. E-commerce packaging plane structure design

The packaging is a 10 sided shape, with all 9 edges except for the connecting edge being pasted and formed, as shown in Fig. 2(d). After forming, only the easy to tear strips of the cover plate and bottom plate can open the packaging as shown in Fig. 2(e). Being able to avoid being maliciously unsealed. The packaging design is heart shaped, which can clearly express the feelings of the lover. After tearing off the easy to tear strip, the packaging is divided into two parts, and the inner liner is pushed out by opening the outer packaging as shown in Fig. 2 (f). Meet the requirements of innovative design and structure.

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Fig. 2. Physical display of e-commerce packaging boxes

2.2 On-Site Packaging Design The on-site packaging materials are all selected as E-corrugated cardboard (200/180100/1E). The on-site packaging uses an one-piece cardboard box with 24 strawberries inside, with a total mass of 0.5 kg. The box shape is also a heart shaped structure. Considering the application environment of on-site packaging, it can be pressed into a flat plate after pasting and molding, and can be pressed into a flat plate after pasting and molding in the packaging factory and transported to the merchant. The structural design and size calculation results are shown in the Fig. 3, the physical effect is shown in Fig. 4.

Fig. 3. Design of on-site packaging plane structure

The packaging is pasted and formed by the manufacturer, and then compressed into a flat shape and transported to the sales site for use. After receiving the packaging, stand

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Fig. 4. Physical display of on-site packaging boxes

the side up and fold the folded plates unfolded on both sides inward to complete the molding. The packaging is shaped like a heart, suitable for couples to give each other as a gesture of love. There is a cover plate on the packaging. After forming, the structure is stable and not easily deformed.

3 Packaging Protection Performance Testing and Analysis 3.1 Vertical Impact Drop Test According to the provisions of GB/T 4857.5-1992 [4]. Conduct vertical impact drop tests on e-commerce packaging using the Su Shi DLJ-100 equipment. The test drop height is 800 mm, and the test results are shown in Table 1. Table 1. Vertical impact drop test results Falling posture

Face drop

Edge drop

Angular drop

Number of drops (times)

1

2

3

1

2

3

1

2

3

Drop height (mm)

800

800

800

800

800

800

800

800

800

Is there any damage

No

No

No

No

No

No

No

No

No

From Table 1, it can be seen that after the 800 mm drop test, the appearance of e-commerce packaging shows no obvious damage, meeting the logistics protection requirements for high-quality strawberries.

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3.2 Pressure Test According to GB/T 4857.4-2008 [5], test the compressive performance of e-commerce packaging. The compressive strength of this packaging was tested using the DCKY50KS computer controlled compressive testing machine, and the experimental results are shown in Table 2. By calculating the compressive strength, it should reach 700N. From Table 2, it can be seen that the average compressive strength of e-commerce packaging reaches 945N, indicating that its structural design can meet the strength requirements of high-quality strawberries in the conventional logistics process. Table 2. Compressive strength test results Test frequency/time

1

2

3

Maximum pressure intensity

852N

1048N

935N

4 Conclusions The use of paper instead of plastic in this packaging meets the requirements of the dual carbon policy and can promote sustainable development. This study enhances the safety and novelty of high-quality strawberry packaging structure through e-commerce packaging and on-site packaging design, making it suitable for various commercial scenarios. The protective performance test results of e-commerce packaging show that it can meet the requirements of effectively protecting the contents in the e-commerce logistics process. The innovative packaging design technology for high-quality strawberries proposed in this article is feasible, cost-effective, and environmentally friendly, providing a new packaging approach for multi-channel sales and delivery of high-quality strawberry ecological fruits.

References 1. Yi, M.: New Standards in the packaging industry boost green and sustainable development. Green Packag. 8, 10 (2022) 2. Li,H.: Origin, evolution, and spread of cultivated strawberries. China Seed Ind. 000(005), 65–65 (2005).https://doi.org/10.3969/j.issn.1671-895X.2005.05.045 3. Yanqing, P., et al.: The effect of pre-treatment combined with modified atmosphere packaging on the quality of mixed fresh cut fruits and vegetables. Food Ferment. Ind. 46(6), 7 (2020) 4. GB/T 4857.5–1992, Test Method for Drop of Packaging and Transportation Packages (1992) 5. GB/T 4857.4–2008, Packaging, Transportation, Packaging - Basic Tests - Part 4: Compression and Stacking Test Methods Using a Pressure Testing Machine (2008)

Experimental Study on the Role of Thermoelectric Cooling System in Short-Distance Food Transportation Chuan Zhang(B) Department of Printing and Packaging Engineering, Shanghai Publishing and Printing College, Shanghai, China [email protected]

Abstract. The utilization of online meal ordering platforms has increased among Chinese citizens in modern society. However, delivering low-temperature food poses challenges. Common practices, such as improving insulation performance or using ice packs, have limitations in effectiveness and convenience. This study incorporates a thermoelectric cooling (TEC) system into food delivery containers to explore its role in short-distance transportation of low-temperature food. Experimental results show that the TEC system significantly reduces the temperature inside the box. When cold water is present, the temperature decline is faster. The TEC system effectively maintains the temperature of cold beverages during delivery and reduces the rate of temperature increase. The compact size of the TEC system allows for easy integration into food delivery boxes, enabling quick implementation of cooling effects. These findings demonstrate the potential of TEC systems in the transportation of refrigerated food and beverages. Keywords: Thermoelectric cooler · Cold beverage · Refrigeration

1 Introduction In modern society, the utilization of online meal ordering platforms has been increasingly embraced and adopted by Chinese citizens. However, the issue of delivering lowtemperature food has become increasingly prominent. During the delivery process, the lack of effective measures can result in an increase in temperature or even the loss of value for low-temperature food upon reaching the consumers’ hands. Common practices include improving the insulation performance of food delivery containers [1] or using ice packs [2, 3] to maintain low temperatures during short-distance transportation. However, these methods have limitations in terms of effectiveness and convenience. The thermoelectric phenomenon was discovered in the 18th century, which involves the generation of a relatively small voltage between two different metals and is primarily used in thermocouples. With the invention of efficient semiconductors, thermoelectric technology has undergone rapid development in the past 60 years due to its unique characteristics distinct from traditional generators and coolers. Nowadays, thermoelectric © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 264–269, 2024. https://doi.org/10.1007/978-981-99-9955-2_34

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technology is widely used in power generation [4, 5], cooling [6], and heating applications [7]. Benefiting from its advantages in refrigeration, thermoelectric refrigeration systems are commonly employed in aerospace, medical devices, electronic components, and other fields [8–11]. This paper attempts to incorporate a TEC system into food delivery containers and explore its role in the short-term transportation of low-temperature food through experimental investigation.

2 Experimental Method As shown in Fig. 1, the device consists of an insulated food delivery box measuring 44 cm × 32 cm × 30 cm and a TEC system, positioned at the side wall of the food delivery box. The TEC system is composed of two Thermoelectric cooler plates with the TEC1– 12706 model, aluminum alloy heat fins, and four fans. It is powered by a stable 12V DC power supply. In the food delivery box, there are four temperature monitoring points, which utilize thermocouples to measure and record changes in the ambient temperature inside the box. The positions of the thermocouples are indicated in Fig. 1.

Fig. 1. Experimental setup

A total of three experiments: 1) cold water is added, and the thermoelectric cooler is not operational; 2) no cold water is added, and the thermoelectric cooling plates are active; 3) cold water was added, and the thermoelectric cooling plates are active. The cold water is contained in a paper cup with a total volume of 400 ml and a temperature of 8 °C. A thermocouple is placed in the water to monitor and record the temperature variations. The ambient temperature outside the box is maintained at 25 °C. The experiment is conducted for a duration of 30 min, which aligns with the typical delivery time for cold beverages.

3 Results and Discussions 3.1 Results Without Cold Water As depicted in Fig. 2, prior to 400 s, the average temperature inside the box decreased at a faster rate compared to after 400 s. Within the first 400 s, the temperature dropped by 7 °C, approximately 1°C per minute. However, after 400 s, the rate of average temperature

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decline inside the box gradually slowed down. Within 1400 s, only a 5 °C decrease was observed. At the conclusion of the experiment, the average temperature inside the box reached approximately 13°C. The temperature difference between the inside and outside of the box was approximately 12 °C. Even without the presence of cold water, the TEC system was able to significantly reduce the temperature inside the box.

Fig. 2. Result without cold water

3.2 Results Without TEC After the start of the experiment, the temperature inside the box gradually decreased, while the temperature of the cold water continued to rise, as shown in Fig. 3. The temperature inside the box decreased from 25 °C to 22.5 °C, resulting in a decrease of only 2.5 °C, with a decrease of 1.8 °C within the first 400 s. From the 400th second until the end, the temperature inside the box remained around 23 °C. On the other hand, the temperature of the cold water increased from 8 °C to 11.7 °C, a total increase of 3.7 °C, the temperature increase of the cold water is linearly correlated with time. At the end of the experiment, there was a significant difference between the temperature inside the box and the temperature of the cold water. 3.3 Results with TEC and Cold Water From the graph, it can be observed that after the start of the experiment, the temperature inside the box began to decrease, while the temperature of the cold water continued to rise. From the beginning to the end, the temperature inside the box decreased from 25 °C to 12.8 °C, with a noticeable decrease of approximately 8.5 °C within the first 400 s. However, from 400 s until the end, the temperature inside the box only decreased by 4.3 °C. Meanwhile, the temperature of the cold water increased from 8 degrees Celsius to 9.2 °C, with a mere increase of 1.2 °C. At the end of the experiment, there was only a 3.6 °C difference between the temperature of the cold water and the temperature inside the box (Fig. 4).

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Fig. 3. Results without TEC

Fig. 4. Results with TEC and cold water

3.4 Comparison of Temperatures Inside the Box From the graph, it is evident that when a TEC system is present, the temperature inside the box decreases significantly faster compared to the scenario without a TEC system. This clearly demonstrates the substantial impact of the TEC system in regulating the ambient temperature inside the box. In both cases with the TEC system, the presence of cold water results in a faster temperature decline inside the box compared to when cold water is not present, and the final temperature inside the box is also lower. We can observe from the graph that when cold water is present, the air temperature inside the box reaches a relatively stable state earlier. This is due to the higher specific heat capacity of water. However, when both cold water and a TEC system are present, the temperature decline curve inside the box can be approximated as a combination of the other two scenarios, with slight variations in temperature values. This is mainly attributed to the difference in temperature gradient between the water and the air, which affects the heat convection in the air and subsequently influences the air temperature (Fig. 5).

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Fig. 5. Comparison of temperatures inside the box

3.5 Comparison of Cold Water As shown in the graph, in both scenarios with and without a TEC system, the temperature of the cold water continues to rise. However, in the presence of a TEC system, the rate of temperature increase in the cold water is significantly lower than in the scenario without a TEC system. In the absence of a TEC system, the temperature of the cold water increases by a total of 3.7 °C within the 30-min period, while in the presence of a TEC system, it only increases by 1.2 °C. The main reason for this difference is the temperature variation inside the box in the two scenarios. This comparison result indicates that a TEC system can effectively maintain the temperature of cold beverages during delivery and reduce the rate of temperature increase (Fig. 6).

Fig.6. Comparison of cold water

4 Conclusions From this study, it can be concluded that TEC system can be effective in the shortdistance transportation of cold beverages and refrigerated food. In the experimental results concerning cold beverages, the use of TEC system significantly helps to maintain the temperature of cold beverages, enabling them to remain at lower temperature

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increase rates during short transportation periods. Additionally, due to the compact size of TEC system, they can be easily integrated into various sizes of food delivery boxes and connected to 12 V power sources in different vehicles, allowing for quick and straightforward implementation of cooling effects. Acknowledgements. This research is supported by Key Lab of Intelligent and Green Flexographic Printing (No. KLIGFP-02).

References 1. Hasan A, Dincer I.: Investigation of new insulation materials for environmentally-benign food delivery bags. In: 7th Global Conference on Global Warming, GCGW 2018. Springer Science and Business Media Deutschland GmbH (2019) 2. Laguerre, O., Chaomuang, N., Derens, E., et al.: How to predict product temperature changes during transport in an insulated box equipped with an ice pack: Experimental versus 1-D and 3-D modelling approaches. Int. J. Refrig 100, 196–207 (2019) 3. Oró, E., de Gracia, A., Cabeza, L.F.: Active phase change material package for thermal protection of ice cream containers. Int. J. Refrig 36(1), 102–109 (2013) 4. Bao, X., Hou, S., Wu, Z., et al.: Mechanical properties of thermoelectric generators. J. Mater. Sci. Technol. 148, 64–74 (2023) 5. Luo, D., Yan, Y., Li, Y., et al.: Exhaust channel optimization of the automobile thermoelectric generator to produce the highest net power. Energy 281, 128319 (2023) 6. Chen, X., Huang, Y., Chen, Z.: Potential evaluation of an annular thermoelectric cooler driven by a dye-sensitized solar cell. Sol. Energy 258, 351–360 (2023) 7. Ximinis, J., Massaguer, A., Pujol, T., Massaguer, E.: Nox emissions reduction analysis in a diesel Euro VI Heavy Duty vehicle using a thermoelectric generator and an exhaust heater. Fuel 301, 121029 (2021) 8. Qin, Y., Zhang, H., Zhang, X.: Integrating high-temperature proton exchange membrane fuel cell with duplex thermoelectric cooler for electricity and cooling cogeneration. Int. J. Hydrogen Energy 47(91), 38703–38720 (2022) 9. Pourkiaei, S.M., Ahmadi, M.H., Sadeghzadeh, M., et al.: Thermoelectric cooler and thermoelectric generator devices: A review of present and potential applications, modeling and materials. Energy 186, 115849 (2019) 10. Hu, B., Shi, X.-L., Zou, J., et al.: Thermoelectrics for medical applications: Progress, challenges, and perspectives. Chem. Eng. J. 437, 135268 (2022) 11. He, W., Zhang, G., Zhang, X., et al.: Recent development and application of thermoelectric generator and cooler. Appl. Energy 143, 1–25 (2015)

Mechanical Engineering Technology

A Combined Decoupling Controller for Register System of Roll-To-Roll Gravure Printing Machines Chaoyue Wang1 , Shanhui Liu1(B) , Jianrong Li2 , Guoli Ju1 , and Wenhui Zhao1 1 Faculty of Printing, Packaging Engineering and Digital Media Technology, Xi’an University

of Technology, Shaanxi, China [email protected] 2 Shaanxi Beiren Printing Machinery Co., Ltd., Shaanxi, China

Abstract. For the nonlinear and strongly disturbing register system of the unit gravure printing machines, a self-tuning method of PID parameters based on RBF neural network is proposed to solve the problem of insufficient dynamic margin of the PID controller in the printing process. Firstly, a nonlinear mathematical model of the global register system is established based on the structure of the gravure printing equipment system and register principle. Then, a PID parameter self-tuning controller integrating RBF neural network is designed for register mathematical model. Finally, the simulations are carried out to verify the control performance of the proposed method in terms of robustness, decoupling performance, and interference resistance. The results show that, compared with the traditional PID controller, the designed controller can better suppress the influence of disturbances and has a higher register accuracy, while solving the problem of controller performance degradation under different working conditions. Keywords: Roll-to-Roll gravure · Register system · RBF · Parameters self-tuning

1 Introduction In the field of gravure printing, the register error is the deviation value of the geometric position of the graphic contour line of each color on the print, which is the difference between the position of the color mark of this level and the position of the previous color mark. At present, the industrial register error is generally controlled at ± 0.02 mm, which will seriously affect the production efficiency of the enterprise if the control accuracy is not satisfactory during printing. However, the roll-to-roll printing system has the characteristics of non-linearity, strong disturbance and multiple working conditions, which makes the register difficult to control. So, it is urgent to propose a high-precision control method for register error that responds to the time-varying controller control performance with working conditions.

© The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 273–278, 2024. https://doi.org/10.1007/978-981-99-9955-2_35

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Many national and international researchers have long modeled and analyzed register systems. Chen established a mechanical model for the acceleration stage of the rollto-roll printing system and designed a model-based feedforward proportional-integralderivative (PID) controller to reduce register errors caused by tension fluctuations [1]. Lee analyzed the influence of thermal deformation and elastic deformation of PET material under drying temperature on registration error and established a registration error model using system identification techniques [2]. Jung proposed an alignment control method using a one-degree-of-freedom mechanical device called AMBR to compensate for web elongation [3]. Chen proposed a fully decoupled proportional-derivative (PD) control algorithm that completely eliminates the coupling between the upper registration controller and the lower web tension controller [4]. Zhang established a mechanical model to represent the direct relationship between registration controllers, using a direct decoupling closed-loop control method with first-order compensation terms to fully compensate for the coupling between errors [5] Ding established the nonlinear mathematical model of the global registration system and realized the self-tuning of ADRC controller parameters based on RBF [6]. Lee identified the main factors of tension disturbance, analyzed the causes of disturbances, determined the registration model, and estimated the registration error by determining the factors [7]. In conclusion, for the problem of multiple working conditions and strong disturbance in unit gravure printing machine, a method of PID parameter self-tuning based on RBF neural network is designed. The structure is as follows: Sect. 2 establishes a 4-color register system model according to the register system structure of gravure machines. Section 3 designs the PID controller incorporating the RBF neural network for the register coupling model, where the RBF performs the real-time rectification of the PID parameters. Section 4 simulates and analyzes the proposed method in terms of robustness, decoupling performance, and anti-interference capability. Section 5 concludes and provides a research outlook.

2 Modeling of Global Register System The gravure printing equipment consists of five units: unwinding, in-feeding, 4-color printing, out-feeding and rewinding. Among them, the register control system is shown in Fig. 1. According to reference [8], the 4-color register error model and the tensionassisted equation between adjacent printing units, with the previous color as the reference, can be described as follows:

Fig. 1. Four color registration system

A Combined Decoupling Controller for Register System

⎧ d e12 (t) = Rω2 (t) − φT1 (t)ω1 (t) − Rω1 (t − tT ) + φT0 (t − tT )ω1 (t − tT ) ⎪ dt ⎪ ⎪ d T1 (t) ⎪ ⎪ = AEϕ(ω2 (t) − ω1 (t)) + ϕT0 (t)ω1 (t) − ϕT1 (t)ω2 (t) ⎪ ⎪ ⎪ d edt (t) ⎪ = Rω3 (t) − φT2 (t)ω2 (t) − Rω2 (t − tT ) + φT1 (t − tT )ω2 (t − tT ) ⎨ 23 dt d T2 (t) = AEϕ(ω3 (t) − ω2 (t)) + ϕT1 (t)ω2 (t) − ϕT2 (t)ω3 (t) dt ⎪ ⎪ d e34 (t) ⎪ = Rω4 (t) − φT3 (t)ω3 (t) − Rω3 (t − tT ) + φT2 (t − tT )ω3 (t − tT ) ⎪ dt ⎪ ⎪ d T3 (t) ⎪ ⎪ = AEϕ(ω4 (t) − ω3 (t)) + ϕT2 (t)ω3 (t) − ϕT3 (t)ω4 (t) ⎪ dt ⎩ R , ϕ = RL L1 = L2 = L3 = L, φ = AE

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(1)

where ω1 -ω4 are the angular velocity of the printing roller; T 0 -T 3 are the coupling interference of the web tension; e12 (t)-e34 (t) are the output signals of the register system; A is cross-sectional area of the web; E is Young’s modulus; R is the radius of the gravure cylinder; L is the length of each span.

3 Design of Decoupled Controller for Register System For the latter angular velocity ω as the control volume, the register error e as the output of the system model, industry often use PID controller for the calculation and processing of the error, its incremental PID algorithm specifically as: 

u(k) = u(k) − u(k − 1) u(k) = kp (k)[e(k) − e(k − 1)] + ki (k)e(k) + kd (k)[e(k) − 2e(k − 1) + e(k − 2)]

(2)

where u(k) is the PID controller control output, u(k) is the control increment, e(k) is the system error at the kth adjustment and k p , k i, and k d are the three parameters of the PID controller. Obviously, for the flexible printing and variable process, the traditional PID controller needs to adjust the parameters frequently by empirical method, which cannot meet the printing requirements under variable working conditions. RBF neural network has faster training speed and better generalization performance, which is suitable for dealing with nonlinear problems. It includes three layers: input layer, hidden layer and output layer, as shown in Fig. 2, the network structure is chosen as 3– 4-1, the input of network is X = [x 1 , x 2 , x 3 ], the radial basis function of the hidden layer is H = [h1 , h2 , h3 , h4 ], the output of the network is ym, = w1 h1 + w2 h2+ w3 h3+ w4 h4 , and the radial basis function is the Gaussian function, which is specified as:    x − C j 2 hj = exp − , j = 1, 2, 3 (3) 2b2j

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where C j = [cj1 ,cj2 ,……,cjn ] is the center vector of the jth node in the network. bj is the base width parameter of node j. The network training rules are: ⎧ E1 = 21 (y(t) − ym (t))2 ⎪ ⎪ ⎪ 1 ⎪ wj (t) = −η ∂E ⎪ ∂wj = η(y(t) − ym (t))hj ⎪ ⎪ ⎪ ⎪ ⎪ ⎪ wj (t) = wj (t − 1) + wj (t)+α[wj (t − 1) − 2wj (t − 2)] ⎨ x−Cj  1 bj = −η ∂E ∂bj = η(y(t) − ym (t))wj hj bj 3 ⎪ ⎪ ⎪ ⎪ b (t)=b (t − 1) + b + α[b (t − 1) − b j j j j j (t − 2)] ⎪ ⎪ xj −cji ⎪ ∂E1 ⎪ cij = −η ∂cij = η(y(t) − ym (t))wj hj 2 ⎪ ⎪ bj ⎪ ⎩ cji (t)=cji (t − 1) + cji + α[cji (t − 1) − cji (t − 2)]

(4)

where y(t) is the register output at moment t, η is the learning rate, α is momentum factor and E 1 is the network recognition performance index, when the network output does not meet the performance index with the system output, each parameter of the network has been adjusted in real time until the network output can achieve a static difference-free tracking of the system output. As shown in Fig. 3, the RBF discrimination network is used for online parameter tuning in combination with discrete PID, with the following specific rules ⎧ ∂y ∂E2 ⎪ ⎨ kp (k) = −η ∂kp = ηp e(k) ∂u (e(k) − e(k − 1)) ∂y 2 (5) ki (k) = −η ∂E ∂ki = ηi e(k) ∂u e(k) ⎪ ⎩ ∂y ∂E2 kd (k) = −η ∂kd = ηd e(k) ∂u (e(k) − 2e(k − 1) − e(k − 2)) where E 2 denotes the system error indicator, E 2 = 0.5e(k)2 ; ηp , ηi , and ηd are the rectified learning rates of k p , k i , and k d , respectively.

Fig. 2. RBF neural network structure

Fig. 3. Self-tuning of PID parameters based on RBF

4 Simulation and Analysis In order to verify the performance of the designed controller, the Simulink module of MATLAB is used for simulation. The substrate is BOPP, the synchronization speed is 150m/min, and each controller parameter is shown in Table 1. The simulation conditions are as follows:

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Table 1. Parameters of each controller Controller

Paraments

Controller

Paraments

PID1

K P1 = 80; K I1 = 50; K D1 = 0

RBF-PID1

ηp1 = 80; ηi1 = 50; ηd1 = 0

PID2

K P2 = 80; K I2 = 50; K D2 = 0

RBF-PID2

ηp2 = 80; ηi2 = 50; ηd2 = 0

PID3

K P3 = 80; K I3 = 50; K D3 = 0

RBF-PID3

ηp3 = 80; ηi3 = 50; ηd3 = 0

(1) Controller performance under tension disturbance. After 10s of system operation, a step of size 10N is superimposed on T 0 , and the simulation curve of register error is shown in Fig. 4. (2) Controller performance under velocity disturbance. After 10s of system operation, a sinusoidal disturbance with an amplitude of 0.1 r/min and a frequency of 0.5 rad/s is superimposed on ω1 , and the simulation curve of the register error is shown in Fig. 5. (3) Controller performance for strip change. After doubling the strip performance (E = 3.6 × 109 ), the simulation curve of register error is shown in Fig. 6 after superimposing a step of size 10N on T 0 after 10s of system operation.

Fig. 4. Tension interference

Fig. 5. Velocity disturbance

Fig. 6. Strip change

For the analysis of the simulation results, (1) under the simulation condition 1, the peak error of the designed controller is 5.61 µm, 4.14 µm and 4.08 µm, and the peak error of the fixed-parameter PID control is 19.95 µm, 19.85 µm and 19.77 µm respectively. (2) Under the simulation condition 2, the peak error of the parameter self-tuning controller control is 2.53 µm, 2.42 µm and 2.33 µm, and the peak error of the PID control is 6.42 µm, 6.36 µm and 6.21 µm respectively. (3) e decreases with the increase of E, and the peak error of the designed controller and the fixed-parameter PID control are 12.52 µm, 12.46 µm, 12.35 µm and 3.92 µm, 3.35 µm, 2.76 µm respectively. Obviously, under the same simulation conditions, the designed controller error peaks are much smaller than those under the fixed-parameter PID control, and the duration is shorter.

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5 Conclusions This paper proposes a PID parameter self-tuning method based on RBF neural network for the nonlinear strong interference register system. By comparing with the traditional PID controller, the designed controller can better suppress the influence of disturbance and has higher register accuracy, meanwhile, it solves the problem of insufficient dynamic margin of the PID controller in the printing process and meets the different printing working conditions. In the future, further algorithm experiments will be carried out on the designed controller and it will be applied to the actual gravure printing machine. Acknowledgements. This project is supported by the Key Research and Development Program of Shaanxi Province (No. 2023-YBGY-329), the Scientific Research Program Funded by Shaanxi Provincial Education Department (No. 22JY048) and the Key Research and Development Program of Weinan City (No. ZDYFJH-45).

References 1. Chen, Y.: Modeling and register control of the speed-up phase in roll-to-roll printing systems. IEEE Trans. Autom. Sci. Eng. 16(3), 1438–1449 (2019) 2. Lee, J.: Analysis of dynamic thermal characteristic of register of roll-to-roll multi-layer printing systems. Robot. Comput.-Integ. Manufact. 35, 77–83 (2015) 3. Jung, H., Nguyen, H.A.D., Choi, J., et al.: High-precision register error control using activemotion-based roller in roll-to-roll gravure printing. Japanese J. Appli. Phys. 57(5S), 05GB04 (2018). https://doi.org/10.7567/JJAP.57.05GB04 4. Chen, Z.: Fully decoupled control of the machine directional register in roll-to-roll printing system. IEEE Trans. Industr. Electron. 68(10), 10007–10018 (2021) 5. Zhang, T.: A direct-decoupling closed-loop control method for roll-to-roll web printing systems. IEEE Trans. Autom. Sci. Eng. 18 (2021) 6. Ding, H.: An ADRC parameters self-tuning controller based on RBF Neural Network for multi-color register system. Machines 11(3), 320 (2023) 7. Lee, J.: Register control algorithm for high resolution multilayer printing in the roll-to-roll process. Mech. Syst. Signal Process. 60–61, 706–714 (2015) 8. Liu, S.: Machine directional register system modeling for shaft-less drive gravure printing machines. Math. Probl. Eng., 1–10 (2013)

Fatigue Life Prediction of Web Folding Mechanism’s Machete Arm Yulong Lin, Tianhao Zhang, and Xinong En(B) College of Mechanical and Electrical Engineering, Beijing Institute of Graphic Communication, Beijing, China [email protected]

Abstract. In engineering practice, 80% of the damage of mechanical parts is caused by fatigue failure. For the web folding mechanism, the machete arm of its single-arm thin-walled structure is its weaker link. During the operation of the folding mechanism, the machete arm is subjected to complex alternating loads caused by multiple excitation, such as self-weight, load and moment of inertia, so it should have strong fatigue resistance in addition to sufficient strength and stiffness. Fatigue damage has the characteristic of sudden “death”, so in order to ensure the reliability and safety of the web folding mechanism during operation, it is necessary to understand the fatigue life level of the machete arm, and it is necessary to conduct fatigue life prediction analysis of the machete arm. Keywords: Folding mechanism · Fatigue life · nCode software

1 Folding Mechanism Rigid Body Modeling The structure of the web folding mechanism is shown in Fig. 1, which is mainly composed of flywheel, connecting rod, machete arm, rollers, wall plate and other components. The machete arm is driven by the crank and connecting rod to do reciprocal swing, the machete is mounted on the machete arm, the paper conveyor belt conveys the paper to the bottom of the machete, the machete pushes the paper into the two rollers, and then the rollers squeeze the paper to complete a horizontal folding action [1, 2]. The 3D rigid model of each part of the folding mechanism was established in the 3D modeling software Creo, and then the parts were assembled to obtain the 3D multi-rigid body model, as shown in Fig. 2. Save it into parasolid format and import it into the fatigue analysis software Ncode for life calculation.

© The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 279–285, 2024. https://doi.org/10.1007/978-981-99-9955-2_36

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1. Gearbox 2.Connecting rod 3.Machete 4.Roller 5.Flywheel 6.Machete arm 7.Base

Fig. 1. Knife folding mechanism of web printing machine

Fig. 2. 3D rigid body model of folding mechanism

2 Standard S-N Curves for Chopper Arm Materials The nCode Design Life software has a rich library of materials, most of which can be known to be called directly from the library [3]. However, the material used for the machete arm of the web folding mechanism in this paper is ZAL alloy steel, for which the nCode material library does not have a corresponding material. Based on this type of situation, nCode DesignLife can define a standard S-N curve for the material based on the tensile strength and the corresponding type parameters. nCode software generates the standard S-N curve for ZAL alloy steel empirically and conservatively, as shown in Fig. 3.

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Fig. 3. Standard S-N curve for ZAL alloy steel

3 Fatigue Life Prediction of Machete Arm Based on nCode 3.1 nCode Design Life Fatigue Analysis Process After integrating nCode Design Life into ANSYS, the fatigue analysis flow can be built automatically in ANSYS Workbench after selecting the appropriate solution engine based on the FEA results. Based on the above results, the fatigue life of the machete arm in the web folding mechanism is predicted using the nCode SN Time Series (i.e., stress-life time series module) module, and the predefined fatigue analysis flow module is built as shown in Fig. 4.

Fig. 4. Predefined fatigue analysis flow construction

After the predefined modules are built, double-click solution to enter the ANSYS nCode Design Life interface, as shown in Fig. 5. In the fatigue analysis flow built in Fig. 5, the system has automatically imported the FEM results of transient dynamics of the machete arm. Based on the flow of the fatigue five block diagram, the next step is to set up the S-N curve, define the load time history, set up the solution engine, and finally estimate the fatigue life of the machete arm in the web folding mechanism based on the above analysis. Among them, the Stress

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Fig. 5. nCode interface

Life Analysis block diagram is the key part of fatigue analysis, which contains “load mapping”, “material mapping” and “solution engine”. The S-N curve is generated in the Stress Life Analysis sub-process “Edit Material Mapping”; the load time history is generated in the Stress Life Analysis sub-process “Edit Load Mapping”, and the solution engine is generated in the Stress Life Analysis sub-process “Advanced Edit”, and can also be performed in Advanced Edit. The “Edit Material Mapping” and “Edit Load Mapping” settings are also available in Advanced Edit. (1) Finite element results The leftmost Simulation Input in the above flow chart represents the finite element simulation result, and the bottommost 1File(s) represents the finite element result has been imported [4]. The simulation result of the transient dynamics simulation analysis of the machete arm at the moment of 2 s is shown in Fig. 6.

Fig. 6. Finite element results

(2) Material mapping The material used for the machete arm in the web folding mechanism is ZAL alloy steel. The standard S-N curve for ZAL alloy steel is generated empirically and conservatively using nCode software, and the defined S-N curve is mapped to the machete arm, as shown in Fig. 7.

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Fig. 7. Material Mapping

(3) Load time course nCode Design Life provides a variety of load mappings, which are set up in the Stress Life Analysis sub-process “Edit Load Mapping”, including: constant amplitude load mapping, time series load mapping, time step load mapping, mixed load It links the FEM solution results with each fatigue solution engine and converts them into the alternating stresses required for fatigue calculations [5]. The load mapping method used in this paper is time step, but it needs to calculate at least one cycle of transient dynamics analysis, using one cycle of load step instead of load spectrum, by calculating the damage of one cycle under the set load step, and then transforming it into fatigue life, and converting the fatigue life into the actual time required for the load step performed in one cycle for analysis, so as to complete the fatigue life calculation. When the machete arm transient dynamics analysis is performed in Chapter 4 section, the solver has been set up for multiple load steps and sub-steps, and only some or all of the loads are selected to participate in the fatigue calculation when fatigue analysis is performed. Since the total duration of the machete arm transient dynamics simulation is set to 2 s, 0–1 s is the acceleration phase of the machete arm, and the machete arm reaches the maximum rated speed by 1 s, 1–2 s is the uniform rotation phase of the machete arm, and the machete arm works with uniform rotation, so the 1–2 s time step is selected as the load time course for the fatigue analysis, as shown in Fig. 8.

Fig. 8. Load time course mapping

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(4) nCode Design Life solution engine settings The standard S-N solver must be used with the standard S-N curve, the previous article generated a standard S-N curve for the machete arm material ZAL alloy steel, in nCode Design Life the standard S-N solver must be used with the standard S-N curve, otherwise the nCode program will report an error, so the SN Method in the solution engine selects Standard. From the analysis above, the Signed Vonmises is selected for the Conbination Method, Goodman is selected for the average stress correction, and the rest of the settings are defaulted, as shown in Fig. 9.

Fig. 9. Solving engine settings

3.2 Analysis of Fatigue Life Prediction Results of Machete Arm After the above settings are completed, click on the “VCR” button directly to solve. nCode Design Life results display the damage value cloud by default, and the fatigue damage cloud of the machete arm after the solution is completed is shown in Fig. 10, and the fatigue life cloud of the machete arm is shown in Fig. 11.

Fig. 10. Machete arm damage cloud

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Fig. 11. Machete arm life cloud

From the machete arm life cloud diagram, the weakest place of its life appears at the root bend of the machete arm, the size is 3.184E + 12. From the actual working condition of the web folding mechanism, the rotation speed of the machete arm is 36000 r/h From the actual working condition of the web folding mechanism, the rotation speed of the machete arm is 36000, and the rotation speed is 10 revolutions per second, i.e., it takes 0.1 s for each rotation, combined with the fatigue life cloud, the total life of the machete arm is 3.184 × 1012 × 0.1 = 3.184E + 12 s.

4 Conclusions The fatigue life of web folding mechanism machete arm is predicted using nCode software in this paper. From the actual working condition of the web folding mechanism, as the rotation speed of the machete arm is 36000 rph combing with the fatigue life cloud, the total life of the machete arm is 3.184 × 1012 × 0.1 = 3.184E + 12 s. Acknowledgements. The research was supported by Science and technology projects of Beijing Municipal Commission of Education (No. KM202110015005).

References 1. Yuan, Y.C., Liu, Y.L., Li, Y.: Optimization design of the web press’s fold mechanism based on robustness. Adv. Mater. Res. 174, 277–281 (2011) 2. Yuan, Y.C., Liu, Y.L., Li, Y.: The robust design of four-bar linkage with clearance based on sensitivity analysis. Appl. Mech. Mater. 34–35, 1656–1660 (2010) 3. Peng, K., Fan, D., Zheng-Peng, B.U., et al.: Failure analysis and parameter optimization for fuel distributor for aeroengine. Tuijin Jishu/J. Propulsion Technol. 32(2), 276–281 (2011) 4. Shen, X.L., Dong, S.J.: Structure optimization and welding residual stress analysis of twin-web turbine disc. Adv. Mater. Res. 622–623, 309–314 (2013) 5. Xue, H.H., Ping, L.S., Bing, L.I., et al.: The failure cause analysis and structure optimization of the duck truck lifting mechanism. Mech. Res. Appli. 39(2), 19 (2013)

Analysis of Key Points in Designing the Contour Curve of the Pressing Cam of Offset Press Hongwei Xu(B) , Dailu Guo, Wanjiang Shi, Jiachen Zhang, and Yanwei Xie School of Printing, Packaging and Digital Media, Xi’an University of Technology, Shannxi 710048, China [email protected]

Abstract. The pressing cam mechanism is an important component of an offset press, and the cam profile is crucial for achieving the follower’s function. In this paper, we analyze the performance of the pressing cam mechanism and introduce the offset method and the envelope method. Using the mechanism module of Pro/E software, we establish models and compute and compare the follower’s accelerated speed of two different pressing cam mechanisms. The results show that the dynamic performance of the cam mechanism with a cam profile designed using the envelope method is better than that of the cam mechanism with a cam profile designed using the offset method. These research results will help the corresponding factory improve the performance of the offset press they manufacture. Keywords: Offset Press · Pressing Cam · Profile · Envelope Method · Dynamic Performance

1 Introduction Offset printing is a vital printing technology used worldwide for producing books, newspapers, magazines, and brochures [1]. In offset presses, various cam mechanisms are employed. Cam mechanisms, which need to operate at a constant speed to specify different output motions, are widely used in mechanical machines due to their precise motion, design simplicity, and relatively low life-cycle cost [2]. Numerous types of cam mechanisms are utilized in various machines, including food, medicine, beverage packaging machines, and more [3]. Many researchers have conducted work on the geometry design of cam mechanisms. Lan [4] identified that design defects in cam transmission mechanisms are often caused by geometric characteristics’ defects, such as curvature interference on contact surfaces and unreasonable pressure angles, significantly affecting dynamic behaviors. They proposed a comprehensive algorithm based on self-contained defect identification algorithms, demonstrating that curvature interference is generally avoided with appropriate processing methods. The design of component sizes directly determines whether pressure angle defects occur. Gao [5] attempted to address problems arising from the coupling clearance of upperlimb cam mechanisms, based on cam entity structure data and motion trajectory characteristics. They established a mathematical model of a cam mechanism using the radial © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 286–292, 2024. https://doi.org/10.1007/978-981-99-9955-2_37

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basis function method to accurately recreate the physical model of the upper-limb exoskeleton’s motion trajectory model. In the case of a pressing cam mechanism for an offset press, it is known that cam mechanisms consist of two elements: the cam and the follower, coupled in a way that theoretically ensures they are always in contact [6]. Typically, the cam is designed with a specific shape to impart the desired motion to the follower. Therefore, designing the contour curve is crucial for designing the cam mechanism. This paper studies the key points in designing the contour curve of the pressing cam for an offset press to ensure the effectiveness of the pressing cam mechanism.

2 Function of the Pressing Cam Mechanism of Offset Press For an offset press, there is an on-off pressure mechanism consisting of two cam mechanisms: the pressing cam mechanism and the off-pressing cam mechanism. These mechanisms operate sequentially. When applying pressure, the rubber cylinder initially contacts the plate cylinder, followed by contact with the impression cylinder. To enable the press to quickly enter a stable state and start printing, an advance angle is typically set, usually around 10°. This method effectively prevents the situation where the first piece of paper is half printed and half empty. Figure 1 depicts the follower’s motion trajectory of the pressing cam mechanism of an offset press.

Fig. 1. Follower motion trajectory of pressing cam mechanism of offset press

From Fig. 1, it can be observed that the first lift is performed on segment a-b by the follower, the stop is executed on segment b-c, the second lift is carried out on segment c-d, the far rest is entered during segment d-e, the return motion is executed on segment e-f by the follower, and the near rest is entered after point f.

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3 Designing the Contour Curve of the Pressing Cam of Offset Press 3.1 Design of Cam Profile Transition Curve Although the transition motion part does not affect the key positions of the follower’s motion trajectory, it does influence the dynamic characteristics of the cam mechanism’s follower. Typically, to ensure the dynamic characteristics of the follower’s motion, the transition curve of the cam profile is designed as a fifth to seventh-degree polynomial. The general expression of the equation of motion for a fifth-degree polynomial transition curve is given in Eq. (1). s = C0 + C1 δ + C2 δ 2 + C3 δ 3 + C4 δ 4 + C5 δ 5

(1)

where, s is the motion angle of the follower, δ is the rotation angle of the cam, and C0 , C1 , C2 , C3 , C4 , C5 is the undetermined coefficient of the fifth-degree polynomial. Taking the derivative of Eq. (1) yields the velocity equation as shown in Eq. (2). ds = C1 ω + 2C2 ωδ + 3C3 ωδ 2 + 4C4 ωδ 3 + 5C5 ωδ 4 dt

(2)

where, ω is the rotation velocity of the cam. Here, assuming the cam’s motion is uniform, ω is a constant value, Taking the derivative of Eq. (2) yields the acceleration equation as shown in Eq. (3). a=

dv = 2C2 ω2 + 6C3 ω2 δ + 12C4 ω2 δ 2 + 20C5 ω2 δ 3 dt

(3)

The boundary conditions: d 2s d 2s ds ds = 0, 2 = 0; δ = δb , s = sb , = 0, 2 = 0 dt dt dt dt 2 d s d 2s ds ds = 0, 2 = 0 δ = δd , s = sd , = 0, 2 = 0 δ = δc , s = sb , dt dt dt dt d 2s d 2s ds ds = 0, 2 = 0; δ = δf , s = 0, = 0, 2 = 0 δ = δe , s = sd , dt dt dt dt

δ = 0, s = 0,

According to the boundary conditions and Eqs. (1)–(3), the curve equations for a-b, c-d, and e-f can be determined. 3.2 Design of Cam Profile Using Offset Method In the on-off pressure cam mechanism of an offset press, a roller is fixed at the top of the follower to reduce friction. Typically, when the follower’s trajectory is specified, the inverse cam generation method is used to determine the cam’s theoretical profile [7]. In this case, the follower’s trajectory represents the trajectory of the roller’s center point, not the contact point between the roller and the cam. There is a distance equal to the roller’s radius between the center point of the roller and the contact point, which forms the practical profile of the cam. To obtain the practical contour curve of the cam, two

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Fig. 2. Draw the cam practical profile using offset method

methods are commonly used: the offset method and the envelope method. For the offset method, the practical contour curve can be obtained by offsetting the theoretical contour curve of the cam inward by a distance equal to one roller radius, as shown in Fig. 2. In Fig. 2, the external curve represents the theoretical contour curve, while the internal curve depicts the actual contour curve. The actual contour curve is generated using the offset method based on the theoretical contour curve. Relative to each point on the theoretical contour curve, the corresponding point on the actual contour curve is determined by measuring the distance from this point to the center of the base circle, which is equal to the radius of the wheel. 3.3 Design of Cam Profile Using Envelope Method The steps of the envelope method involve drawing a series of circles with each point on the theoretical contour curve of the cam as the center and the roller radius as the radius. Subsequently, draw the envelope lines of these circles, which are formed by connecting the outermost points of all circles. This envelope curve represents the actual contour curve of the cam, as illustrated in Fig. 3. From Fig. 3, it is evident that the practical profile of the cam is formed by the envelope of the rollers, aligning with the actual working conditions of the cam mechanism. The contour curve of the cam obtained through this method ensures that all points on the cam maintain contact with the rollers throughout the entire motion, thereby guaranteeing the correctness of the follower’s motion trajectory.

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Fig. 3. Draw of cam profile using envelope method

4 Motion Analysis of the Cam Mechanism Designed by the Two Difference Methods Because the cam profile can be designed using either the offset method or the envelope method, there are differences in the cam profile curves created using these two methods. In this section, kinematic analysis will be performed on the cam mechanism to determine which method of designing the cam mechanism exhibits better dynamic performance. Simulation software is commonly employed for mechanism performance analysis [8]. In this case, Pro/E software is used to model the two cam mechanisms separately. Referring to the press cam mechanism of the offset press, appropriate simplifications were applied, and corresponding mechanism models were established using Pro/E software. In the models, one cam mechanism is the one designed using the offset method for its cam profile, and another cam mechanism is the one designed using the envelope method for its cam profile. The mechanism module of Pro/E software is employed to calculate the follower’s acceleration separately for these two different mechanisms. The cam speeds for both mechanisms are set at 110r/min, and the follower’s acceleration curves are obtained as shown in Fig. 4 and Fig. 5. From Fig. 4, it can be observed that the maximum accelerated speed is 20590 rad/second2 . Correspondingly, the maximum accelerated speed is 13411 rad/second in Fig. 5. Clearly, the maximum accelerated speed of the follower in the cam mechanism designed with the envelope method for the cam profile is lower than that of the cam mechanism designed with the offset method. In terms of follower accelerated speed, a smaller value is preferred.

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Fig. 4. Follower accelerated speed curves of the cam mechanism designed by the offset method

Fig. 5. Follower accelerated speed curves of the cam mechanism designed by the envelope method

5 Conclusions For a cam mechanism, the cam profile is crucial in achieving the follower’s function. Through the study on the design of the cam profile for the pressing cam mechanism of an offset press, it can be concluded that the first step in designing the pressing cam profile is to specify the follower’s trajectory. The inverse cam generation method can be used to determine the cam’s theoretical profile based on the follower’s motion trajectory. To achieve better dynamic performance of the follower in the pressing cam mechanism, the best approach is to create the practical cam profile using the envelope method. Although the envelope method is more complex than the offset method, it ensures the reliable motion trajectory and dynamic performance of the follower in the pressing cam mechanism.

References 1. Lundström, J., Verikas, A., Tullander, E., et al.: Assessing, exploring, and monitoring quality of offset color prints. Measurement 46 1427–1441 (2013) 2. Ouyang, T., Wang, P., Huang, H., et al.: Mathematical modeling and optimization of cam mechanism in delivery system of an offset press. Mech. Mach. Theory 110, 100–114 (2017) 3. Chang, Z., Changmi, X., Pan, T., et al.: A general framework for geometry design of indexing cam mechanism. Mech. Mach. Theory 44, 2079–2084 (2009)

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4. Lan, W., Fan, S., Fan, S.: Analysis of structural design defects in parallel overloading mechanisms with cam transmission mechanism. Appli. Math. Model. 107, 717–739 (2022) 5. Gao, L., Ma, C.-J., Zhou, N., et al.: Optimization design method of upper limb exoskeleton cam mechanism’s motion trajectory model. Comput. Ind. Eng. 171, 108427 (2022) 6. Borboni, A., Aggogeri, F., Elamvazuthi, I., et al.: Effects of profile interpolation in cam mechanisms. Mech. Mach. Theory 144, 103652 (2020) 7. Pozo-Palacios, J., Fulbright, N.J., Voth, J.A.F., et al.: Comparison of forward and inverse cam generation methods for the design of cam-linkage mechanisms. Mech. Mach. Theory 190, 105465 (2023) 8. Kang, G.-J., Song, W.-J., Kim, J., et al.: Numerical approach to forging process of a gear with inner cam profile using FEM. J. Mater. Process. Technol. 164–165, 1212–1217 (2005)

Systematic Design of Efficient Circulating Oven to Ensure Functional Coating Quality Hongqi Chen2 , Fangdong Wang1 , Luhai Li1(B) , and Yushui Chen2 1 Guangdong Olger Precise Machinery Technology Company Limited, Guangdong, China

[email protected] 2 Beijing Engineering Research Center of Printed Electronics, Beijing Institute of Graphic

Communication, Beijing, China

Abstract. The consistency of the drying process has a significant impact on the quality of coated products. Through comprehensive and continuous research on the causes of coating drying defects, starting from the drying quality requirements of various products, combined with the basic principles of air jet fluid mechanics, based on the principle of heat exchange consistency, by controlling the wind temperature and pressure to ensure consistent drying effects, we have designed and manufactured an efficient circulation drying oven with systematic control; Through online monitoring, the drying process is accurately quantified and controlled. The dynamic mixing and diversion of cold and hot air through different functional areas of the air duct maintain a temperature error of < ± 1 °C at the outlet of the air nozzle. This oven can be precisely adjusted according to the drying conditions of different functional coating products, ensuring consistent drying heat exchange rate of the coating and consistent evaporation rate of solvent on the coating surface without blind spots. It has achieved controllable solvent residue in the coating product, isotropic coating, consistent density, bending resistance, no lateral color difference, no longitudinal rib pattern, no internal stress deformation and warping, and no aging, brittleness/moire in the coating, and can maximally overcome the defects of uneven drying on the surface and inside of high viscosity thick coatings. Keywords: Precision coating · Drying system · Drying heat exchange rate · Volatilization rate · Electrical control

1 Introduction High quality functional coating products, such as PCB photosensitive film, photoresist corrosion-resistant dry film, medical thermal printing film, solar backing film, lithium battery separator, hydrogen battery proton exchange membrane, membrane electrode, reverse osmosis membrane, liquid crystal/electronic optical film, etc., have extremely high requirements for coating quality. In actual production, the appearance of the coating layer, residual drying solvents, uniformity and consistency of drying, and substrate tension may all lead to coating quality issues. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 293–302, 2024. https://doi.org/10.1007/978-981-99-9955-2_38

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The uniformity and consistency of wet coating drying directly affect the quality of the coated product. In ordinary coating units, except for the drying system, the accuracy of other unit modules is relatively intuitive and controllable; In the coating operation, with changes in parameters such as viscosity, solid content, and wet coating amount of the coating liquid, it is necessary to adjust the outlet temperature of the drying oven’s air nozzle and the air volume of the inlet/outlet fans accordingly. However, the heat exchange drying and volatile exhaust gas discharge on the coating surface are invisible and intangible. Due to significant changes in the process parameters of the oven and the inability to accurately control the temperature/air volume at the outlet of the air nozzle, it is impossible to ensure a uniform and stable distribution of drying heat exchange in the coating layer, which directly leads to surface defects and even physical and chemical performance defects in the coated product, thereby affecting the product’s application performance [1]. Cheng et al. [2, 3] used Solid Works software to model the air fluid domain between the jet nozzle and the electrode in order to optimize the jet pressure distribution of the lithium battery coating oven nozzle. Based on k- ε The turbulence equation completes the numerical simulation calculation of the hot air flow field. Based on the fluid simulation results, the structure of the jet nozzle is optimized and designed. The consistency between experimental data and numerical simulation results is verified, and it is believed that the optimized jet nozzle improves the jet pressure distribution. Li [4], in order to obtain the current sharing and resistance characteristics of the wind blade used in the lithium battery electrode drying box and verify the correctness of the numerical simulation results, based on geometric similarity, used organic glass material to make a wind blade performance test box with the same structural size as the numerical simulation model. Using inlet flow rate and outlet pressure as boundary conditions consistent with numerical simulation to achieve motion similarity. By measuring the pressure difference between the inlet and outlet at different flow rates, the resistance characteristics of the wind blade are obtained; Use a hot wire anemometer to measure the wind speed point by point along the outlet of the wind blade, and obtain the current sharing characteristics of the wind blade on the air. The experiment shows that under the same overall size and operating conditions, the resistance of the air knife with a bottom sieve plate and inner liner is relatively small, and the pressure difference between the inlet and outlet is between 33 and 524 Pa. The flow uniformity is the best, and the airflow uniformity at the outlet is above 95%; The wind blade with a top air outlet circular hole and no inner liner has the lowest resistance, with a pressure difference of 24–354 Pa between the inlet and outlet. Its flow uniformity is the worst, and the outlet airflow uniformity is 80.4%, which cannot meet the usage requirements; The blade with no bottom sieve plate and inner liner and a narrow air outlet has the highest resistance, and the pressure difference between the inlet and outlet is between 203 and 3234 Pa, which cannot meet the drag reduction requirements. Its flow uniformity is good, and the outlet airflow uniformity is 91.1%. Select the best performance cavity structure scheme from 5 different coating air suspension oven cavities. Song Jianhui [5] used the Fluent module of Ansys software to simulate the working conditions of 5 types of air suspension oven cavities by modeling them in 3D. By comparing the simulation results, it was determined that the working effect of the air distribution baffle type oven cavity was better than that of other oven

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structures. Zhang et al. [6] conducted structural parameter optimization of the coating machine suspension oven. They used SolidWorks to establish a model and divide the fluid domain, used Gambit software for grid division and inspection, used Fluent for fluid simulation calculations, and evaluated the drying performance of the oven by calculating velocity and pressure statistics; The influence of distance and angle of the oven box on drying performance was obtained, and the optimal tilt angle and front distance selection range of the suspension oven box were studied. This provides a theoretical basis and parameter selection scheme for the design of the suspension drying system of coating equipment. Bai et al. [7] adopted the standard k to address the impact jet flow field distribution and influencing factors of the V-shaped slot nozzle in the printing and coating equipment oven- ε. The turbulence model numerically simulates the impact of nozzle jet on the moving wall, and it is considered that the ideal nozzle height is 15mm and the nozzle width is 2.5mm. Based on continuous research on the causes of drying defects, Guangdong Olger has developed and manufactured an efficient circulation drying oven based on the principle of air jet fluid dynamics, achieving quantitative drying control. It can accurately control the drying heat exchange rate of coatings to maintain consistency and control the solvent evaporation rate on the surface of the coating layer without blind spots according to the drying conditions of different functional coating products.

2 Overall Design The drying system is one of the key components in the coating production process. The drying process directly affects the performance, form, quality, and energy consumption of the product, which can both improve and reduce the performance of the coated product. It can be seen that the drying system is equally important as the coating process, and the impact of the drying process on the production of certain precision coating products may be higher than that of the coating process. The commonly used methods for coating drying include convection drying, contact drying, radiation drying, etc. The hot air impact jet drying technology is the most common coating drying method. The drying process involves complex heat and substance transfer. During the physical evaporation drying process, solvent molecules move from the inside of the coating to the surface and diffuse to the environment at a certain evaporation rate from the surface. The changes in each drying stage involve complex heat transfer mechanisms, are related to the latent heat of solvent evaporation and the intermolecular forces between coating components, and are closely related to the material processing mode. Finally, it achieves different drying effects through various mechanical structures and application processes of drying equipment [5, 6]. Figure 1 shows the principle of convective drying [7]. A hot air body with a temperature of t and a humidity partial pressure of p flows through the surface of the coating. Driven by the temperature difference, heat is transferred from the gas phase to the coating surface, achieving the heat transfer process. After the moisture absorbs heat, the surface vapor pressure increases, forming a saturated gas film on the coating surface. The temperature of the gas film is approximately equal to the wet bulb temperature tw of the hot air, and the vapor pressure at temperature t is higher than the wet partial pressure

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p of the gas phase main body. The moisture diffuses from the material surface to the gas phase main body, achieving mass transfer at the liquid vapor interface. At this point, there is a concentration difference between the surface moisture and the internal moisture of the coating, and the internal moisture will move towards the surface for internal mass transfer. As the drying progresses, the gas film will move from the surface to the interior, and the vapor pressure on the coating surface undergoes a process of saturation to unsaturation as the drying progresses.

Fig. 1. Coating convection drying principle

The necessary condition for achieving coating drying is that the partial pressure of water vapor on the coating surface must be greater than the partial pressure of water vapor in the drying medium, and the difference in partial pressure between the two determines the drying rate. The driving force for mass transfer comes from the timely removal of the generated solvent vapor by the drying medium. The drying rate depends on the heat and mass transfer rates, and it can be seen that the uniformity and consistency of coating drying largely depend on the consistency and uniformity of mass and heat transfer processes controlled by the drying equipment and drying process. Ding [8] aimed at the spray airflow velocity of different structure nozzles in suspension drying. From the simulation results, the velocity contour maps of the hot air flow passing through the auxiliary planes of each type of nozzle were intercepted, and the uniformity of the spray airflow velocity was compared. The distribution of the spray airflow velocity value was compared using the Chart function of Ansys software. Huang Tianlun from Huazhong University of Science and Technology [9] established a mathematical model for analyzing the structure of a lithium-ion battery electrode drying oven and optimizing the nozzle flow field characteristics in the suspension drying of lithium-ion battery electrode sheets. It was found that the structural form of the intake box had little effect on the uniform air effect, and the near wall flow fields in the areas controlled by the suspension nozzles in the drying box were basically not affected by each other. Based on the above findings, a mathematical model for optimizing the divergent holes of a single suspension nozzle was established, and the influence of the number of divergent holes on heat transfer uniformity, average heat transfer performance, pressure uniformity, average pressure performance, and comprehensive performance was analyzed. The design of the Olger high-efficiency circulation drying oven focuses on two types of factors:

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1) The drying effect of the oven is consistent. Mainly reflected in three aspects: firstly, the consistency of hot air temperature, that is, the temperature error of a single box (area) is not greater than ± 1 °C. The second is the consistency of heat exchange rate, that is, the deviation of the longitudinal accumulated value of wind speed and temperature from any point at the outlet of the air nozzle is controlled within ± 1%; The third is the consistency of air duct pressure, that is, the air pressure difference between the two air nozzles in the oven is not greater than ± 5 Pa; Only by achieving quantitative and precise control in these three aspects and maximizing the consistent solvent evaporation rate of the coating can the consistent drying effect of the coating be ensured. 2) There should be a high tolerance for the adaptation of the range of substrate materials and their coatings. One is to adapt to the variation range of substrate thickness, width, and tension; The second is to adapt to changes in the wet coating amount of the coating.

3 Structural Design Taking the structure of the high-efficiency circulation drying oven designed by Guangdong Olger as an example, this paper explains the composition of this high-efficiency circulation drying oven, analyzes the quantitative key indicators during its use, and compares its performance with ordinary drying ovens. The high-efficiency circulation drying oven is composed of an oven body, an inlet and outlet air circulation system, a heat exchanger, a hot air filter, a heat source device, a control system, etc. Drying process: Cold air passes through a heat exchanger and becomes hot air, which is directly blown to the coating boundary to form a turbulent state. Hot air in the flow heats up the coating and substrate, while taking away the solvent in the coating. The solvent can easily be transferred from the coating to the drying airflow, and turbulence makes the evaporation of the solvent faster. The mixed hot air can be recycled or discharged. Due to the increase in heat transfer coefficient, the drying time of the coating in the constant speed range is shortened, which increases the drying rate. The design scheme ensures that the air nozzles are reasonably distributed and close to the substrate, and the drying process maintains a turbulent state of the boundary layer at a high airflow speed. An effective reflux state can cause air to impact the coating and prevent the retention of evaporated solvents (as shown in Fig. 2). 3.1 Temperature Consistency Design The temperature consistency here refers to the temperature error of a single box (area) temperature control being less than ± 1 °C. Compared with the structure of the internal air duct of the static pressure box in a regular oven (as shown in Fig. 3), the internal air duct of the high-efficiency circulating drying oven is divided into several parts: air inlet, mixing zone, splitter plate, pressure equalizing zone, air nozzle, and substrate. The dynamic mixing and diversion of cold and hot air through different functional areas of the air duct results in a temperature error of < ± 1 °C at the outlet of the air nozzle. Usually, the temperature error of the hot air in a regular oven is less than ± 5 °C.

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Fig. 2. Structure of an efficient circulating drying oven

Fig. 3. Schematic diagram of ordinary oven air duct mechanism

The significance of keeping the temperature error range at the outlet of the air nozzle narrow is to ensure the stability of the airflow temperature, achieve consistency in the transfer of drying heat at that point, and thus ensure the uniformity of the drying effect. 3.2 Consistency of Heat Exchange Capacity In order to ensure the consistency of heat exchange rate during the drying process, two indicators need to be clearly defined: 1) the deviation of the longitudinal accumulated wind speed at any point of the air nozzle outlet in the entire box should be controlled within ± 1%; 2) The deviation of the longitudinal accumulated temperature value at any point of the air nozzle outlet in the entire box should be controlled within ± 1%. The deviation of the longitudinal accumulated temperature value is less than ± 1%, which refers to the coating substrate film passing through several sections of the oven from the inlet to the outlet. Each oven has several nozzles, and the deviation of the longitudinal accumulated temperature value at any point of the nozzle outlet is less than 1%. If the temperature of the four stage oven (12 nozzles per box) is set to 60 °C, 80 °C, 100 °C, and 90 °C, the total temperature value of the longitudinal temperature

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accumulation value is (60 °C + 80 °C + 100 °C + 90 °C) × If 12 = 3960 °C, the deviation of the longitudinal measured cumulative value is less than 39.6 °C (less than 1%). The deviation of the longitudinal accumulated wind speed value is less than ± 1%, which refers to the coating base film passing through several sections of the oven from the inlet to the outlet. Each oven has several nozzles, and the deviation of the longitudinal accumulated wind speed value at any point of the nozzle outlet is less than 1%. If the process wind speed of a four stage oven (with 12 nozzles per box) is 3 m/s, 8 m/s, 10 m/s, and 15 m/s, the reference value for the longitudinal accumulation value of wind speed is (3 m/s + 8 m/s + 10 m/s + 15 m/s) × 12 = 432 m/s, then the deviation of the longitudinal measured cumulative value of wind speed is less than ± 4.32 m/s (less than 1%). 3.3 Consistency of Air Duct Pressure Inside the Box While meeting the balance and high precision of inlet air speed and temperature, it is also necessary to exhaust evenly. Only when the inlet and outlet air reach a balance of a micro pressure field (± 5Pa), as shown in Fig. 4, and at the same time ensure that the micro pressure between each two nozzles in the oven is consistent, can the point-topoint discharge of the entire oven solvent be achieved, so that the airflow field on the substrate surface passing through each nozzle is consistent, Ensure the consistency of solvent saturation at any horizontal point on the surface of the substrate coating, ensure the consistency of mass transfer effect, and thus ensure the consistent drying effect at each horizontal point of the coated substrate.

Fig. 4. Schematic diagram of ordinary oven air duct mechanism

From the data in the table, it can be seen that by strictly controlling the outlet temperature and wind speed of the air nozzle, as well as controlling the pressure of the oven duct, the stability of heat exchange at each point of the oven is maintained, and thus the stable and consistent drying performance of the coating passing through each drying point is ensured.The results of the oven wind speed test are shown in Table 1 and 2.

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Oven section

Nozzle number

OS (Operating side) (m/s)

M(middle) (m/s)

DS (Power side) (m/s)

No.1

1

10.2

9.7

9.5

2

11.5

11.1

10.8

3

11

13

12.7

4

12.4

13

13.1

5

10.4

10.6

10.6

6

9.5

9.5

9.7

7

10.9

9.5

10.1

8

11.2

10.2

10.6

9

10.5

11.1

9.8

10

10.7

10.2

10

11

11.9

10.7

11.7

12

11.2

11.8

11.9

Vertical cumulative values:131.4 Longitudinal cumulative value deviation:(131.4–130.77)/130.77 = 0.0048

Vertical cumulative values:130.4 Longitudinal cumulative value deviation: (130.4–130.77)/130.77 = 0.0028

Vertical cumulative values: 130.5 Longitudinal cumulative value deviation: (130.5–130.77)/130.77 = 0.002

Vertical cumulative values mean: (131.4 + 130.4 + 130.5) /3 = 130.77

4 Electrical Control The high-efficiency circulating drying oven mainly has three controllable quantities: oven temperature, oven inlet and outlet air volume (return air ratio), and inlet and outlet air pressure difference. The control quantities corresponding to different coating processes, such as substrate material, width, and operating speed, have a certain corresponding relationship with electrical control parameters. Based on long-term research on the drying system of the coating machine, the main idea to achieve the optimal control scheme is to combine long-term accumulated application experience and use computer-aided design software to simulate the drying system of the coating equipment under different operating parameters, analyze and calculate the optimal control results under different operating parameters. The system controls the intake and exhaust air circulation system by installing temperature sensors, pressure differential sensors, pressure switches, etc. inside the oven. As the main controller of the system, the PLC processes various sensor or command signal inputs on site, performs logical control on on-site equipment, processes bus data driven by frequency converters or servo drives, monitors and controls the temperature control unit through the bus, and can collect and exchange data with the upper computer SCADA or MES system for on-site data collection and control instuctions. According

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Table 2. Actual test results of oven wind speed (Inlet fan 30HZz) Oven section

Air nozzle number

OS (Operating side) M (middle) (m/s) (m/s)

DS (Power side) (m/s)

No.1

1

6.1

6.8

6.7

2

6.2

6.3

6.5

3

6.2

6.8

6.6

4

6.2

6.0

6.1

5

6.3

6.5

6.8

6

6.4

6.0

6.0

7

6.4

6.1

6.0

8

6.3

6.1

5.8

9

6.4

6.1

6.2

10

6.4

6.4

6.3

11

6.2

6.2

6.2

12

6.2

6.2

6.4

Vertical accumulation value: 75.3 Deviation of longitudinal cumulative value: (75.3–75.45)/75.45 = -0.0026

Vertical accumulation value: 75.5 Deviation of longitudinal cumulative value: (75.5–75.45)/75.45 = -0.0060

Vertical accumulation value: 75.6 Deviation of longitudinal cumulative value: (75.6–75.45)/75.45 = 0.019

Mean value of longitudinal accumulation: (75.3 + 75.5 + 75.6) /3 = 75.45

to the requirements of wet coating with different thicknesses, the system automatically matches the temperature/air volume requirements under different working conditions (the inlet fan can be adjusted at 25–50 Hz) for operation. PLC automatically controls the air volume of the entire system [10]. The pressure difference sensor detects the pressure status inside the oven and forms a closed-loop control circuit with the exhaust frequency converter to ensure that the pressure inside the oven is in a micro negative pressure state. Each group of ovens is equipped with 1–2 sets of heat source devices, and the heating methods can be electric heating, thermal oil heating, hot steam heating, etc. Taking electric heating devices as an example. In the heat source device, the temperature control unit controls each group of electric heaters through a three-phase power regulator. The temperature control unit can use a conventional intelligent temperature control meter (or multi-channel intelligent temperature control module), and the PLC system communicates with the intelligent temperature control meter (or multi-channel intelligent temperature control module) through Modbus RTU protocol to monitor and control the temperature of each group of ovens in real-time.

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The system writes the relevant process parameters of the specific model into the PLC through the HMI touch screen. The PLC queries the relevant process data and selects the optimal control parameters to control each subsystem (temperature control system, intake and exhaust air circulation system), achieving control of the oven temperature, air volume, and return air ratio. Relevant achievements have formed local standards for coating machines [11].

5 Conclusions The Guangdong Olger Precision Coating/Composite Unit applies duplex winding and unwinding, no speed reduction docking film, precise constant tension drive for the entire line, ultra-low tension control for the base film operation in the oven air duct, efficient circulation drying, multi-mode precision coating, and industrial bus control system to form a precision coating production line suitable for various multi-functional coating products. The above production line is based on quantitative drying control technology. In practical applications, the solvent residue in the coating product is controllable, the coating density is consistent, resistant to bending, no lateral color difference, no longitudinal rib pattern, no internal stress deformation and warping, and the coating is free from aging, brittleness, and moire. It can also overcome the defects of uneven drying on the surface of high viscosity thick coatings to the maximum extent. Acknowledgements. Key Project of the Science and Technology Plan of the Beijing Municipal Education Commission (No. KZ202110015019).

References 1. Li, L.: Coating and Lamination Technology. Printing Industry Press, Beijing (2017) 2. Cheng, Q., He, S., Hu, H., et al.: Optimization of jet pressure distribution in lithium battery coating oven. Packag. Eng.. Eng. 40, 180–186 (2019) 3. Cheng, Q., He, S., Hu, H.: Analysis of uniform flow characteristics and structural optimization of lithium battery ovens. Light Ind. Mach. 37, 89–93 (2019) 4. Li, X., Gao, D., Wang, H.: Experimental and numerical simulation comparative study on the internal flow characteristics of the air knife in a lithium battery electrode drying box. J. Mech. Eng. 51, 105–111 (2015) 5. Jianhui, S., Ding Junjian, T., Zhigang,: Computer simulation and simulation analysis of the chamber of a coating drying air suspension oven. Pack. Eng. 40(19), 223–229 (2019) 6. Zhang, H., Liu, J., Xue, Z., et al.: Optimization of structural parameters for the suspension oven of a coating machine. Mech. Design. Res. 31, 142–146 (2015) 7. Bai, W., Bao, N., Xu, Peng., et al.: Numerical simulation of jet flow field impacted by V-shaped slot nozzles in printing and coating ovens. Pack. Eng. 32, 28–32 (2011) 8. Compiled by the Japanese Chemical Society: Fundamentals and Progress of Coating Drying Technology. Sanhui Co., Ltd, first edition in, Nagoya (2020) 9. Jin, R.: Design coating oven. Hangzhou Chem. Indus. 3, 37–39 (2007) 10. Zhang, H., Pan, D., Cheng, X., et al.: Drying model and calculation of an image recording material. Inform. Recording. Mater. 22, 1–5 (2021) 11. Ding, J.: Study on the relationship between the structure of air suspension drying nozzles and air flow stability. Paper and Paper 35, 8–10 (2016)

Intelligent Optimization Technology in Design of Printing and Packaging Equipment Minwang Liu(B) Shaanxi Beiren Printing Machinery Co., Ltd., Shaanxi, China [email protected]

Abstract. This paper examines the application of intelligent optimization technology in the design of printing and packaging equipment, with a focus on its use in intelligent design. The paper also explores the use of genetic algorithm, artificial neural network, and simulated annealing algorithm in intelligent optimization technology. The paper reviews the development and classification of intelligent optimization technology and discusses its applications in the manufacturing industry, specifically in the context of intelligent design for printing and packaging equipment. Through case studies and analysis, the paper identifies the challenges and requirements faced by the promotion and application of intelligent optimization technology in printing and packaging equipment intelligent design. Finally, it proposes strategies and measures to promote research and application of intelligent optimization technology in this field, such as conducting more research on the advantages and limitations of different algorithms, improving collaboration between academic institutions and industry, and promoting the adoption of intelligent optimization technology through training and education programs. Keywords: Intelligent optimization technology · Printing and packaging equipment · Intelligent design · Genetic algorithms · Artificial neural networks · Simulated annealing algorithms

1 Introduction With the rapid advancement of infotech and industrialization, intelligent manufacturing has become a significant trend in manufacturing. The digitization, intelligence, and efficiency of printing and packaging equipment can be achieved through intelligent design technology, which improves equipment quality, reduces costs, and shortens cycles, thereby enhancing efficiency and level. Intelligent optimization technology, a core component of intelligent design, plays an important role in the intelligent design of printing and packaging equipment. Therefore, research on the intelligent optimization of printing and packaging equipment design technology is crucial for promoting intelligent manufacturing, enhancing efficiency, and improving the overall manufacturing level. In recent years, intelligent optimization technology has been widely used in the manufacturing industry with the development of intelligent manufacturing technology. Researchers have conducted studies on its application in the intelligent design of printing and packaging equipment. The results show that it has achieved certain optimization © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 303–308, 2024. https://doi.org/10.1007/978-981-99-9955-2_39

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effects but there are still challenges to be addressed. The most commonly used intelligent optimization technologies in printing and packaging equipment design include genetic algorithm, artificial neural network, and simulated annealing algorithm. Combining multiple technologies can lead to better optimization outcomes. Future development trends involve combining intelligent optimization technology with other intelligent technologies such as the Internet of Things, big data, and cloud computing to further improve efficiency, reduce costs, and promote sustainable development in the printing and packaging industry.

2 Overview of Intelligent Optimization Technology Intelligent optimization technology is a comprehensive technology that combines artificial intelligence and mathematical optimization theory. It has several characteristics, including adaptability, parallelism, global search capability, and robustness [1]. This technology can be classified into various types based on implementation method and application field, such as genetic algorithms, simulated annealing algorithms, ant colony algorithms, particle swarm optimization algorithms, and artificial neural networks [2]. Each type has its unique characteristics and scope of application, and hybrid intelligent optimization technology can be formed by combining them to adapt to complex and diverse practical scenarios. The development of intelligent optimization technology can be traced back to the optimization theory of the 1950s, which gradually developed into an independent research field with the continuous improvement of computing power. Since the 1990s, the research on intelligent optimization technology has entered a rapid development period, with the emergence of various new algorithms and methods and expanding application fields. Currently, it is widely used in manufacturing, power systems, communication networks, finance, and other fields, achieving good results and economic benefits. With the development of Industry 4.0, intelligent optimization technology has become an essential technical support for promoting intelligent manufacturing and industrial transformation and upgrading. It can be employed for optimization of manufacturing process, product design, and production planning. In manufacturing process optimization, its primary goals are to improve efficiency, reduce costs, and enhance product quality [3].

3 Intelligent Optimization Technology for Smart Design of Printing and Packaging Equipment Genetic Algorithm-based Intelligent Optimization has been widely used in various fields, including the design of printing and packaging equipment. Genetic Algorithm is an algorithm inspired by biology that simulates the process of evolution. It mimics natural selection and genetic inheritance to optimize solutions through operations such as crossover, mutation, and selection. In the context of smart design of printing and packaging equipment, Genetic Algorithm can be utilized to optimize the structure, control parameters, and process flow of packaging machinery, thereby enhancing its performance and efficiency [4]. This method has the advantage of searching for optimal solutions among a broad

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range of possibilities and handling complex multi-objective optimization problems. In the intelligent design of printing and packaging equipment, Genetic Algorithm can be applied to areas such as structural optimization, loading problem optimization, logistics path optimization, etc. As shown in Fig. 1, the implementation steps include: Determining optimization goals - Identifying the optimization targets for intelligent design of printing and packaging equipment, such as minimizing costs or maximizing production efficiency. Building a mathematical model - Constructing a mathematical model based on the specific problem and representing it as a fitness function. Initialization of the Genetic Algorithm - Defining the basic parameters of the Genetic Algorithm like population size, crossover probability, mutation probability, etc. Selection operation Selecting excellent individuals based on the value of the fitness function to increase their survival chances, and choosing individuals with higher fitness scores for reproduction. Crossover operation - Applying crossover operation on selected parent genes to generate new offspring genes. Mutation operation - Performing mutation operation on newly generated offspring genes to introduce diversity. Repeat the above steps - Continuously repeating the above operations until the preset number of iterations is reached or the optimal solution that meets the optimization goal is found. Researchers have extensively applied and studied the optimization of intelligent design for printing and packaging equipment using Genetic Algorithms. For instance, in certain instances where structural optimization was required for packaging machinery, optimization methods based on Genetic Algorithms significantly enhanced packaging machinery performance and reduced production costs. Similarly, researchers used Genetic Algorithms to optimize process parameters of packaging machinery, significantly reducing failure rates during production and improving overall production efficiency.

Fig. 1. Flowchart of the Genetic Algorithm

Artificial Neural Networks (ANN) optimization in printing and packaging equipment design mainly focuses on model building, parameter optimization, and predictive analysis [5]. As shown in Fig. 2, it learns from historical data to build a mathematical

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model, adjust parameters for improved performance, and predict future equipment performance, providing manufacturers with more accurate plans and decisions. However, it requires significant data and computational resources, as well as continuous adjustments to network structure and parameters. Challenges persist in its practical application.

Fig. 2. Fully connected Neural Network

Simulated Annealing Algorithm (SA) optimization in printing and packaging equipment design focuses on designing and optimizing equipment. SA is a stochastic global search algorithm that finds optimal or close-to-optimal solutions. Unlike Gradient-based algorithms, SA introduces randomness and probability to achieve search [6]. In printing and packaging equipment, SA can optimize design parameters like stress, material cost, and machine weight. By defining an objective function and constraints, SA searches for the optimal solution. It has better global convergence and search capability than other optimization algorithms, making it suitable for complex problems. SA can be combined with other algorithms like Genetic Algorithm (GA) and Particle Swarm Optimization (PSO) to improve results. Further improvements in efficiency and accuracy can be made by increasing search times and refining search strategies. Intelligent optimization technology has become a widely adopted solution in the printing industry, with the aim of optimizing various aspects of the printing process. One such aspect is the optimization of printing color accuracy. By employing intelligent optimization algorithms, color parameters in the printing process can be fine-tuned, leading to improved color accuracy and reduced waste as well as production costs [2]. Moreover, intelligent optimization technology can also be employed to enhance packaging size and structure design. This is particularly important for industries that need to cater to different products and transportation methods. By establishing mathematical models based on optimization algorithms such as simulated annealing, considering factors like stability, load capacity, and space occupation of packaging materials, packaging size and structure design optimization can be achieved [1].

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4 Intelligent Design Technology for Printing and Packaging Equipment: Strategies and Challenges for Intelligent Optimization Promotion and Application The promotion of intelligent design technology for printing and packaging equipment faces multiple challenges that need to be addressed. These challenges include the diverse demands of different products, technical complexity, high equipment costs, and difficulty in implementing practical applications. To overcome these challenges, it is important to strike a balance between ensuring equipment quality and performance while controlling costs. This can be achieved through continuous adjustments and improvements in practice and the comprehensive use of various intelligent optimization technologies.Establishing close partnerships with manufacturers, suppliers, customers, and research institutions is one strategy that can be taken to jointly promote the application and promotion of intelligent optimization technology. This will facilitate knowledge sharing and collaboration in the field, which can lead to better solutions and increased efficiency.Another important measure is to improve the awareness and knowledge level of practitioners through various channels such as training, seminars, and forums. This will enable them to better understand the benefits and potential of intelligent optimization technology, which can help them make more informed decisions when designing and optimizing printing and packaging equipment.Finally, successful cases and experiences should be shared and highlighted to increase awareness and interest among other enterprises. Governments can also play a role by formulating relevant policies such as financial incentives, tax exemptions, innovation funds, etc. to support the application and promotion of intelligent optimization technology in the field of printing and packaging equipment. By implementing these strategies and measures, it is possible to overcome the challenges faced in promoting intelligent design technology for printing and packaging equipment and achieve better results in terms of equipment quality, performance, and cost-effectiveness.

5 Conclusion and Prospects Research has shown that intelligent optimization technology-based intelligent design methods can effectively find optimal solutions in the design process, enhancing product quality and efficiency while decreasing production costs. This demonstrates significant application value and promotes potential for further development. However, practical applications of intelligent optimization technology face challenges such as algorithm complexity and difficulties in data acquisition and processing. In the future, with the continuous advancements in artificial intelligence and big data technology, the utilization of intelligent optimization technology in printing and packaging equipment design will become even more widespread and diverse. Nevertheless, issues such as algorithm efficiency and stability, data quality and reliability must be addressed to optimize the application of intelligent optimization technology. Therefore, future research will focus on enhancing algorithms, improving data quality and reliability, and combining various intelligent optimization technologies to further advance the application of intelligent optimization technology in intelligent design of printing and packaging equipment.

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Acknowledgement. This research was supported by Key Technologies Research and Application of Intelligent Packaging and Printing Factory (No. 2020QFY0-08).

References 1. Kou, Y., Ma, C.: Dual-objective intelligent vehicle lane changing trajectory planning based on polynomial optimization. Physica A Stat. Mech. Appl. 617 (2023) 2. Xie, H., Wei, L., Kumar, A., et al.: Optimization mechanism of virtualized database log system under the background of intelligent technology. In: Proceedings of the 2nd International Conference on Cognitive Based Information Processing and Applications (CIPA 2022), pp. 455–461 (2023) 3. Geng, Z.: Intelligent BIM building technology (BT) based on optimization algorithm. In: Proceedings of the 2nd International Conference on Cognitive Based Information Processing and Applications (CIPA 2022), pp. 693–702 (2023) 4. Wang, Z., Chinthavali, M., Campbell, S.L., et al.: A 50-kW air-cooled sic inverter with 3-D printing enabled power module packaging structure and genetic algorithm optimized heatsinks. IEEE Trans. Ind. Appl. 55(6), 6256–6265 (2019) 5. Alhaddad, W., He, M., Halabi, Y., et al.: Optimizing the material and printing parameters of the additively manufactured fiber-reinforced polymer composites using an artificial neural network model and artificial bee colony algorithm. Structures 46, 1781–1795 (2022) 6. Fontes Dalila, B.M.M., Homayouni, S.M., Gonçalves, J.F., et al.: A hybrid particle swarm optimization and simulated annealing algorithm for the job shop scheduling problem with transport resources. Eur. J. Oper. Res. 306(3), 1140–1157 (2023)

User Experience Focused Design of Online Printing Quotation System Guojun Kang1 , Huaming Wang1 , Jiong Liang1(B) , Yuansheng Qi1 , and Jia Wang2 1 Beijing Institute of Graphic Communication, Beijing, China

[email protected] 2 Yunnan Opening University, Kunming, Yunnan, China

Abstract. The printing and packaging industry are confronting great challenges in the digital era. One of the most problems is the professional talents’ shortage, which becomes more severe nowadays. The paper studies on the development of a quotation app on printing product with easy-to-use features and without much demand for professional knowledge. The app can help build the fluent communication between the print buyer and print shop when a business begins. Focusing on the user experience rules, we purpose an innovative method to connect the material consumption to the product components and then to their real production processes in a digital mode, substituting the traditional description style based on the BOM (bill of material) of product which depends largely on the businessman’s professional calculation in manual mode. The new method supports the quotation process on the digitized professional knowledge and experiences in printing and also on the smart functions’s automatic calculation following the practical operation, which ensures the production involved data in accordance along all the production processes. While the app is intuitive and easy to use, it can also keep the quotation precise and reasonable. This exploratory research is on one of the key problems in the aspects of smart printing production. The developed online pricing app can help to realize the fluent data exchange between print customer and printing shop. Its data collection mode guarantees the realization of globally digital and smart communication during the whole production procedures. Keywords: Product BOM · User experience · Printing quotation · Printing process · Intelligent calculation

1 Introduction As a traditional industry, the printing industry is facing the challenges of informationization, digitalization, lean production, and intelligent transformation. The quotation system is a key link in communicating with customers and is particularly important for expanding the market. The manufacturing processes serve for various complicated and diversified printing products, which covers wide range of knowledge. That results in insufficient flexibility or inability of many quotation systems, especially if the operator is without a very strong professional background. Solving the problems on the customized services, the user experience, the user satisfaction and loyalty have become particularly urgent. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 309–316, 2024. https://doi.org/10.1007/978-981-99-9955-2_40

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The Internet expands the communication channel between customers and enterprises by the online quotation system. A customer-experience focused system should be friendly to users, which most importantly means to reduce the dependence on the professional background, better serving some non-professional users, which will bring more competitive advantages to printing companies and closely meet market demand.

2 User Experience (UX) User Experience refers to the real feeling and overall experience formed by users when using a product or service [1, 2]. User experience consideration on a product’s development is crucial to help maximize users’ value and enhance their advantage in competition [3]. To meet the personalized needs of printing users seeking quotes online and provide an excellent user experience, UX design first requires attention to interface aesthetics, usability, and consistency to provide an intuitive, easy-to-use, and enjoyable operating experience. Additionally, UX design needs to consider identifying the target users of the product or system based on their characteristics, interests, cultural beliefs, gender, social groups, and lifestyles [4]. For example, the target users of the printing industry may have a certain level of technical knowledge and industry experience. Moreover, the essence of UX is to focus on the pain points and needs of users. By understanding the expectations and goals of the users using the online quotation system, UX design should provide corresponding solutions.

3 Related Work In order to satisfy customer with high-quality printing service in short time, the printing companies have gradually formed a set of standardized industry solutions for sales orders following their rich industry experience. This system has named as BOM-based quotation mode, where the production number, material, processes, pricing and the other aspects will be considered along the production procedure. 3.1 Traditional BOM-Based Quotation Model The printing enterprises always make quotation on the BOM-based method. BOM refers to the bill of materials and the corresponding processes. It describes the production procedure of a printed product, including the quantities and units of measurement, the bills of material, and the list of controlled engineering components [5]. A salesman is responsible for the content formation of material based on his professional understanding on the component structure and working processes of the current product, and input them into a quotation system to get the price sum [6, 7]. BOM analysis is the core of manufacturing design for the integrated product data management [8, 9], and it will run through all manufacturing cycle of a product production. The BOM-based quotation model aligns with the traditional management habits of printing enterprises, and provides a clear list of materials and processes of the production. The BOM-based quotation mode faces the following problems in modern manufacturing [10, 11]:

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1) Manual calculation and estimation error: Traditional BOM-based quotation is highly dependent on the operator’s professional knowledge and industry production experience. Many details need to be designed and estimated manually (as shown in Fig. 1). 2) Lack of flexibility and customization: The traditional BOM quotation mode is adaptable for the standardized products, whereas lacking flexibility and customization. 3) Inaccurate material consumption: The traditional BOM quotation model often only considers the quantity and price of materials required for single product, while unable for the actual consumption of materials for multi-product mixed production process. 4) Unable to adapt to the requirements of lean production: Products in the printing industry have extremely flexible production processes and material applications, and there are many customized details that need to be considered in different style of products.

Fig. 1. Flowchart of BOM-based quoting process

3.2 Internet-Based Quotation Method The development of Internet technology has promoted the intelligent and wisdom transformation of printing enterprises. The online quotation app has been widely used in the industry. The BOM-based is the core logic of these quotation apps. Analyzing the online quotation apps in printing with many user accounts, we found that there are two problems: 1) The quotation usually aims at relatively simple product types. The parameters, selected materials and processes are universally used for different products. Facing more complicated processes or processing parts, it still depends on the way of manual budget creation and manual input. 2) The digitization of production processes is not enough. A clear description logic on the product-component-process has not been completely formed. The intelligence is also on low level, and in adaptable to the production mode of the digital factory. The above two problems lead to the insufficient data standardization, hindering the quoting app to integrate with systems such as enterprise resource planning system (ERP), manufacturing execution system (MES) and advanced planning and scheduling system (APS). The online quotation function in a digital and intelligent production system is not only an Internet-based upgrade of the quotation function, but also with the concept to establishing a complete product-oriented production system.

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4 Proposed Method The UX focused quotation model will break the traditional BOM-based quotation model from the perspectives of the production management logic based on professional knowledge, and use intelligent derivation mechanism to achieve accurate price calculation through data input, and finally send satisfactory personalized quotation schemes to customers (as shown in Fig. 2).

Fig. 2. Flowchart of UX focused quotation process

Here, an app on the product of hardcover book is created to give the detailed explanation on the propose method. 4.1 UI (User Interface) Design In terms of UI design to improve the user operation efficiency and satisfaction in operation, the following improvements have been made:

Fig. 3. Hardcover book product information input interface

1) Concise and clear layout: Organize and assign the product data items into the reasonably sequent web pages to make them clearly visible (as shown in Fig. 3). 2) Intuitive and easy-to-understand guidance: Clear labels, indicators, and buttons settings on the interfaces help user understand exactly what each action means and does. 3) Input requirement simplification: Users are only required to input the basic and necessary data. Some default values and automatically filled textboxes are set to minimize the amount of user input and simplify the operation process. In Fig. 4, the cover size is a calculated value based on the parameters set on the preceding pages, such as the finished product size, case binding style, flap, block binding method etc.

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Fig. 4. Data input interface of book cover

4) Chosen controls and interactive elements are easy-to-use: Choose controls and interactive elements that are easy to use and operate, such as drop-down menus, radio buttons, check boxes, etc. In Fig. 5, there are four regions. The values of inside pages are inherited from the preceding input; the printing colors are assigned separately on front and back with three selected items, CMYK, single black and CMYK + Spot colors. The item settings are helpful for user to determine clearly when they are operating.

Fig. 5. Hardcover book input interface of inside pages

4.2 Information Architecture Design The app guides the user to decompose the product components, and fill in the necessary product attributes following the production process sequence. The correct product components and production logic are the clues to organize the data structure, which takes the following advantages: 1) To understand the component structure clearly: By breaking down a hardcover book into the components, the management system can know a product well and clearly. 2) To organize the material BOM based on the order of the production process and display the process BOM simultaneously: Through the timeline guidance, the user can fill in data on the component parts autonomously according to the product process

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sequence. This step-by-step method can help users not miss any necessary information throughout the quoting process, ensuring the accuracy and completeness. 3) To establish a production-oriented database on product components and technique processes: Considering on the problem of the traditional ERP system in the underlying data structure, the app organizes data on the processing sequence of product components, keeping connection between the processing logic and the components’ parts. 4.3 Intelligent Parameter Determination Method The product requirement combines with the actual production procedure, and the intelligent calculation is performed by executing preset rules or algorithms. 1) Prospect of optimal solution and reasonable cost: By automatically calculating key factors such as paper size, process or material consumption, the app can output the optimal solution following the user’s demand. 2) Reduce the operator’s requirements for professional data calculation: This intelligent calculation method reduces the burden on the operator and no longer requires them to have in-depth professional data calculation capabilities. Instead, they can rely on the system’s intelligent computing capabilities, which reduce errors and increase productivity. Figure 6 is a procedure logic for jacket size calculation based on the system input parameters such as the book block size, the block thickness and flap size etc. 3) Improvement of user experience: Using the app, the users can save time and effort and receive consistent and reliable quotes satisfying their demands, which enhances the user’s experience.

Fig. 6. Calculation procedure for rounded-back hardcover jacket size

4.4 Customized Setting Scheme In actual operation, we are often limited by factors such as resource shortage, equipment capacity, and cost consideration etc. In addition, changes in the market condition will also lead to price fluctuation, which are actual that must be considered. On this consideration,

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the app also allows the recalculation from the recommendation value based on the user’s manual input in addition to the intelligent method. In Fig. 7 on paper constraints, the recommended values can be ignored and the user is permitted to uncheck it and add other value choices. And then the app will help the user to judge which choice will be the best one.

Fig. 7. Hardcover book material constraint input interface

4.5 To Satisfy Multiple Types of Users Generally, the printing companies ensure satisfying their major customers and provide high-quality service, even with a dedicated service team for them. However, for some scattered demands, the companies may have certain deficiency in resource investment, service support and response. The UX focused quotation mode can meet various smallbatch business and improve business response speed through automatic calculation and quotation, which brings and keeps the better development opportunities for the printing companies.

5 Conclusions This paper analyzes the problems of the traditional Bom-based quotation model existing in traditional printing enterprises, and proposes a quotation model based on user experience design. Exploratory research was conducted on key issues in intelligent printing production. This method establishes the digitization of industry practical experience, and on this basis, converts customer product requirements into digital logic through interactive operations, and enables the quotation process to become fast and accurate through intelligent analysis and calculation algorithms. However, the rationality of system application needs to be combined with the data collection and analysis logic of ERP systems, and even depends on the ultimate realization of APS functions. Therefore, we will promote the practical application of this method in subsequent research in combination with relevant aspects. Acknowledgements. We would gratefully acknowledge the fund support of the BIGC Scientific Research Project (No. BIGCEc202302) to this research.

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References 1. InteractionDesign, User Experience (UX) Design (2023). https://www.interaction-design.org/ literature/topics/ux-design 2. Hartson, R., Pyla, P.: Chapter 1 - What are UX and UX Design? The UX Book, 2nd edn, pp. 3–25 (2019) 3. Choma, J., Guerra, E.M., Alvaro, A., et al.: Influences of UX factors in the Agile UX context of software startups. Inf. Softw. Technol. 152, 107041 (2022) 4. Wong, M.L., Khong, C.W., Thwaites, H.: Applied UX and UCD design process in interface design. Procedia Soc. Behav. Sci. 51, 703–708 (2012) 5. Watts, F.B.: Chapter Five - Bill of Material (BOM) Process, pp. 97–118. William Andrew Publishing (2010) 6. Zheng, H., Yang, F., Zhou, X., et al.: Research on BOM management for the entire lifecycle of aerospace products: a case study of aerospace launch support systems. Spacecraft Recov. Remote Sens. 43(2), 142–150 (2022) 7. Kang, Y., Yan, H., Wang, Y., et al.: Research and practice of multi-BOM management based on product lifecycle. China Manag. Inform. 22(17), 95–98 (2019) 8. Zhang, H., Shi, S., Shi, Q.: BOM data management and practice for PLM. Manuf. Autom. 40(8), 30–34 (2018) 9. Yang, Y.: On the relationship modeling between pdm system and bom system. Automot. Sci. Technol. 4, 133–220 (2017) 10. Daniela, Q., Cristian, R., Virginica, R.: A methodology to develop usability/user. Experience heuristics. Comput. Stand. Interfaces 59, 109–129 (2018) 11. An, B.: From expertise to the ultimate: interpretation of the colorful quotation system. Digit. Print. 3, 43–45 (2016)

Numerical Simulation of Two-Component VOCs Gas Treatment in a Three-Bed Regenerative Oxidation Furnace Hao Wan1 , Jinlong Du2 , Peng Liu1(B) , Xuefan Zhang1 , Mingying Zhou1 , and Yujuan Yao1 1 School of Printing Packaging and Digital Media, Xi’an University of Technology, Xi’an,

Shaanxi, China [email protected] 2 Beiren Brofind (Xi’an) Environmental Technology Co., Ltd, Xi’an, China

Abstract. At present, most research on the three-bed regenerative oxidation furnace only stays at the level of numerical simulation of combustion after a singlecomponent gas enters the device. However, in actual printing and packaging companies, the gas components are diverse and complex. Therefore, in order to be as close as possible to the actual production situation, this paper selects two gases that account for a larger proportion in VOCs exhaust gas for research: toluene gas with higher calorific value and ignition point, and ethyl acetate gas with lower calorific value and ignition point. The three-dimensional model and fluid domain model of the three-bed regenerative oxidation furnace were established using Solidworks software, and numerical simulation was carried out using the computational fluid dynamics (CFD) software Fluent. The thermal efficiency changes of the operating device under different proportion conditions were studied. The numerical calculation results can guide the precise adjustment and control of the actual production of the three-bed regenerative oxidation furnace. Keywords: Three-bed regenerative oxidation furnace · Two-component gas · CFD · Numerical simulation

1 Introduction The Regenerative Thermal Oxidizer (RTO) has the characteristics of high thermal efficiency and high exhaust gas purification rate [1, 2], so it has been widely used in the treatment of VOCs exhaust gas in the printing industry [3]. Among them, the three-bed RTO has added a purge chamber optimization structure [4] compared to previous products, achieving more excellent heat recovery performance and exhaust gas treatment effects, and has received widespread attention in the industry. At present, the research on the combustion situation of single-component exhaust gas entering the three-bed RTO is quite mature, but under actual working conditions, the composition of the gas entering the equipment is complex, so the situation of single-component combustion is not enough to truly reflect the real performance of the three-bed RTO. This article © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 317–322, 2024. https://doi.org/10.1007/978-981-99-9955-2_41

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selects two gases that account for a higher proportion in the printing industry’s exhaust gas for research [5], namely toluene gas with higher ignition point and calorific value, and ethyl acetate gas with lower ignition point and calorific value. Using computational fluid dynamics methods, the thermal efficiency changes of the operating device under different proportion conditions were studied. The thermal efficiency of dual-component gas combustion obtained by numerical simulation using Fluent software is of guiding significance for the precise control of enterprise three-chamber RTO.

2 Theoretical Analysis and Calculation Model Establishment 2.1 Physical Model The RTO three-bed regenerative combustion device used in this paper has a design thermal efficiency of 95%. The honeycomb ceramic heat storage material used is commonly used mullite [6]. The specifications of a single heat storage body are 150 mm * 150 mm * 300 mm, the number of channels is 43 * 43, the wall thickness is 1.0 mm and the porosity is 64%. The height of the three heat storage chambers of the three-bed regenerative combustion device is 1500 mm, and the lateral cross-sectional size is 1350 mm * 1200 mm. It is filled with 5 layers of honeycomb ceramic heat storage bodies with the dimensions of 150 mm * 150 mm * 300mm. The overall height of the device is 2900 mm, the total length is 5800 mm, and the distance between two adjacent heat storage rooms is 880 mm. Since the model is regular, the divided grid has good quality, and the final number of grid divisions is 263772. The divided three-bed regenerative combustion device is shown in Fig. 1.

Fig. 1. Mesh division diagram of three-bed heat storage and combustion unit

2.2 Simulation Model Turbulence Model. This study uses the RNG k-epsilon (k-ε) turbulence model, which is derived using the statistical method of renormalization group theory [7]. Compared with the standard k-ε model, the RNG model has the advantages of high accuracy in high-speed flow, high precision in vortex flow, and provides an analytical formula for turbulence Prandtl number.

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Combustion Model. The Finite-Rate/Eddy-Dissipation model is used for simulation in this study [8]. This model simply combines the Arrhenius formula and the eddy dissipation equation. Its advantage is that it takes into account both kinetic factors and turbulence factors and is suitable for single-step reactions. This model can simulate most gas phase combustion problems. 2.3 Evaluation Index of Three-Bed RTO Performance The ratio of the actual used heat and the theoretical used heat in the regenerative body is the thermal efficiency, whose Formula (1) is as follows: ηr =

T − Tout 100% T − Tin

(1)

T , Tin and Tout represent the combustion chamber temperature, exhaust gas inlet temperature, and purified gas outlet temperature, respectively. 2.4 Chemical Combustion Mechanism of VOCs Waste Gas The components of waste gas produced in real industry are very complex, and toluene and ethyl acetate are the main components in these waste gas components. The chemical equations for the combustion of toluene and ethyl acetate are shown in Formula (2) and Formula (3). Toluene combustion formula: C7 H8 + 9O2 → 7CO2 + 4H2 O

(2)

Ethyl acetate combustion formula: C4 H8 O2 + 5O2 → 4CO2 + 4H2 O

(3)

3 Effect of Change of the Ratio of Two-Component Gas on Temperature When the inlet gas velocity is 1.28 m/s, the purge air volume is 0.128 m/s, and the switching time is 60 s, the thermal efficiency change of the regenerative combustion device is studied under seven conditions: the total concentration of the two gases is 4000 mg/m3 , and the specific gravity of toluene is 1/8, 1/4, 3/8, 1/2, 5/8, 2/3, and 7/8. 3.1 Effect on Combustion Chamber Temperature It can be seen from Fig. 2 that the combustion chamber temperature will continue to drop as the specific gravity of toluene decreases. This is because the calorific value generated by the combustion of ethyl acetate of the same concentration is less than that generated by the combustion of toluene, so when the specific gravity of ethyl acetate increases, the heat generated by the gas per unit time in the combustion chamber will decrease, resulting in a decrease in the combustion chamber temperature.

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Fig. 2. Effect of changing toluene concentration on combustion chamber temperature

3.2 Effect on Outlet Temperature As can be seen from Fig. 3, with the specific gravity of toluene decreases, the outlet temperature changes little. This is because in a regenerative combustion device, the outlet temperature is mainly restricted by the heat conduction of the regenerative skeleton, while the high-temperature flue gas in the combustion chamber is absorbed by the upper layer of the regenerative body when it flows through the regenerative body for heat release. The influence of changing the concentration ratio of the exhaust gas on the internal temperature of the regenerative body is shown in Fig. 4 and Fig. 5: changing the proportion of toluene from 7/8 to 1/8.The temperature gradient of the accumulator skeleton does not change obviously, so the outlet temperature does not change much.

Fig. 3. Effect of change of toluene concentration on outlet temperature

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Fig. 4. Temperature cloud map of toluene ratio 7/8

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Fig. 5. Temperature cloud map of toluene ratio 1/8

3.3 Effect on Thermal Efficiency The concentration and specific gravity of toluene decrease, the temperature of the combustion chamber decreases, and the outlet temperature changes little. According to the calculation formula of thermal efficiency, it can be concluded that the thermal efficiency will decrease with the concentration and specific gravity of toluene. Therefore, when the concentration of VOCs gas is constant, increasing the concentration and specific gravity of gases with high calorific value will help improve the thermal efficiency of the regenerative combustion device. The change of thermal efficiency with the increase of toluene concentration and specific gravity is shown in Fig. 6.

Fig. 6. Effect of change of toluene concentration on thermal efficiency

4 Conclusions This paper studies toluene and ethyl acetate gases with different concentration ratios under the condition that the total concentration of VOCs gas is unchanged, and finally draws the following conclusions.

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When the total concentration of VOCs gas is the same, the specific gravity of toluene decreases, which will cause the combustion chamber temperature to continue to drop. However, as the specific gravity of toluene decreases, the outlet temperature does not change significantly. The final thermal efficiency will decrease with the decrease of the concentration and specific gravity of toluene. Therefore, when the concentration of VOCs gas is constant, increasing the ignition point and the concentration and specific gravity of the gas with high calorific value will help to improve the thermal efficiency of the regenerative combustion device. Acknowledgements. This research is supported by the Technological Innovation Guidance Plan of Shaanxi Province, (No. 2020QFY03-02).

References 1. Yang, Z., Liu, X.-W., Li, L., et al.: Research progress of thermal oxidation technology of volatile organic waste gas. Chem. Ind. Progr. 36(10), 3866–3875 (2017) 2. Luan, Z., Hao, Z., Wang, X.: Analysis and evaluation of VOCs treatment technology for industrial fixed sources. Environ. Sci. 32(12), 3476–3486 (2011) 3. Shuai, Q., Dong, X., Lu, J., et al.: Research progress of regenerative combustion treatment of industrial VOCs waste gas. Environ. Sci. Technol. 44(1), 134–140 (2021) 4. Dai. Q.: Analysis and design optimization of VOCs treatment in two-bed regenerative oxidation furnace. Shanghai Workers (4): 25–28 (2020). https://doi.org/10.16759/j.carolcarrollnki. ISSN 1004-017-x.2020.04.010 5. Wei, J., Liu, X., Sui, B., et al.: Analysis of exhaust gas characteristics and influencing factors of cigarette pack printing production. China Environ. Protect. Ind. 269(11), 60–62 (2020) 6. Yuan, F.: Research on temperature simulation and optimization of regenerative baking and turnover process of ladle. University of Science and Technology Beijing (2018) 7. Li, L., Li, Y.: Numerical simulation of turbulent flow around blunt body using turbulence model based on RNG method. Progr. Water Sci. 4, 357–361 (2000). https://doi.org/10.14042/j.carolc arrollnki32(1309),pp.04,2000.002 8. Wu, C.: Application of turbulent combustion model in combustion chamber numerical calculation. Shenyang Institute of Aeronautical Technology (2009)

Mechanical Properties Analysis for Telescopic Arm of a Trolley for Replace Plates Haiyang Ji1 , Li’e Ma1(B) , Shilin Feng1 , Donghao Ma1 , and Huning Sun2 1 School of Printing, Packing Engineering and Digital Media Technology, Xi’an University of

Technology, Xi’an, Shaanxi, China [email protected] 2 Shannxi Beiren Printing Machinery Co., Ltd., Weinan, China

Abstract. A new type of plate loading trolley composed of a telescopic arm and a swinging mechanism can improve the replacement efficiency of the plate roller and simplify the operation process. The telescopic arm will bend downwards under the weight of the plate roller, making the wing area more prone to deformation. The mechanical characteristics of the telescopic arm of the modified trolley are analyzed in this article, and the calculation methods for the deflection and stress of the wing plate area of the telescopic arm are provided. The finite element analysis of the structure of the telescopic arm was carried out, and the validity of the stress and deflection model in the wing area of the telescopic arm was verified by comparing the results of theoretical analysis. The research in this article provided a theoretical basis for the design of a new type of plate loading trolley. Keywords: Telescopic arm · Deflection · Stress

1 Introduction The trolley for replace plates belongs to the light transport vehicle in the field of material handling machinery. In gravure printing enterprises, the installation of the plate roller requires the cooperation of the plate loading trolley and manpower to achieve the installation and disassembly of the plate roller [1]. The telescopic arm was widely used in military, environmental sanitation, rescue and other fields due to its flexibility and high space utilization. The stress analysis of the local area of the telescopic arm mainly analyzes the stress in the contact area between the slider and the arm body. Milk Savkovic [2] analyzed the factors that affect the stress in the contact area, created a mathematical model with geometric parameters, and compared the numerical calculation results of the model with the finite element method and experimental testing, verifying the correctness of the mathematical model. This article provides the deflection and stress formulas of the telescopic arm under stress conditions, and verifies its effectiveness through finite element analysis.

© The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 323–328, 2024. https://doi.org/10.1007/978-981-99-9955-2_42

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2 Structure of the Telescopic Arm A modified trolley has a swinging mechanism and telescopic arm on the basis of the traditional trolley structure. The telescopic arm studied in this article adopts a rectangular cross-section type, with a structure consisting of two upper and lower wing plates and two left and right web plates. The overall structure is composed of the basic arm, the second arm, and the third arm, as shown in Fig. 1.

Fig. 1. Structure of modified trolley

3 Analysis of Mechanical Characteristics of the Telescopic Arm The state conditions of the telescopic arm under working condition is shown in the figure, from left to right are the basic arm, the second arm, and the third arm. The symbol G represents the self-weight of each arm, l represents the extension length of the arm, x 1 and x 2 represent the overlapping length, A and B are the contact points between the arms, N is the support reaction force, and P is the gravity applied by the plate roller to the telescopic arm (Fig. 2). l1 N A0

N B0

x0

A0

x2

x1

A1 B0 G0

l2

x3

A2 B2

B1 G1

Fig. 2. Free-body diagram of telescopic arm

G2

P

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A coordinate system was established which the center of the telescopic arm section as the origin. Among them, σx represents the stress in the x-axis direction, σy represents the stress in the y-axis direction, and τxy represents the shear stress (Fig. 3).

Fig. 3. Local force of telescopic

Firstly, based on the Kirchhoff hypothesis [3] and the local force of telescopic the description formulas of stress are Established.  2  ⎧ Ez ∂ w ∂2w ⎪ σ = − + μ ⎪ 1−μ2  ∂x2 ∂y2  ⎨ x Ez ∂2w ∂2w (1) σy = − 1−μ2 ∂y2 + μ ∂x2 ⎪ ⎪ 2 ⎩ Ez ∂ w τxy = − 1+μ ∂x∂y In Formula (1), w is the deflection, E is the elastic modulus, and μ is the Poisson’s ratio. Using double trigonometric series [4] to express the bending deflection of the local area of the flange [5]: w=

∞  ∞  m=1 n=1

amn sin

nπ y mπ x sin a b

(2)

In Formula (2), n and m is a positive integer, anm is an undetermined coefficient, and anm can be determined using the principle of virtual work [6], a is the length of the telescopic arm section, and b is the width of the telescopic arm section. The deformation of flange plate can be calculated by Rayleigh Ritz [7] method, and the Strain energy generated by bending is: ˚ 1 (3) Vε = (σx εx + σy εy + τxy γxy )dxdydz 2 In Formula (3), εx is the linear strain of the x-axis direction, εy is the linear strain of the y-axis direction, and γxy is the shear strain in the xy-plane. Finally, the derivation

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process is omitted in this paper and according to the virtual displacement principle [8, 9], the formula for local deflection of the wing plate is as follows: ∞ ∞   1 8 w= 4 m2 π abD m=1 n=1 ( a2 +

n2 2 ) b2

2abq0 mπ x0 nπ y0 sin (sin + mnπ 2 a b

mπ x0 mπ u nπ v 2nq0 a3 nπ y0 nπ y1 sin ) sin sin − (sin + 2 3 b 2a 2b bπ m a b

αm mπ u nπ v tanh αm − cosh2 αm nπ y mπ x nπ y1 ) sin sin sin sin sin αm b 2a 2b tanh αm + cosh2 α a b sin

(4)

m

In Formula (4), D is the bending strength of the plate, q is the load on the surface of plate, u is the length of loading area, v is the width of loading area, and am = π mb/2a. By combining Formulas (1) and (4) the stress component in the local area of the wing plate can be obtained. Using the above formula to calculate the deflection and stress using different series, the following results can be obtained [10] (Table 1). Table 1. Calculation results of different series terms Series

Center Deflection

σ x_max

σ y_max

2

0.2367 mm

30.6440 MPa

26.5467 MPa

5

0.2381 mm

32.0136 MPa

26.8581 MPa

10

0.2381 mm

31.9693 MPa

26.8465 MPa

20

0.2381 mm

31.9733 MPa

26.8476 MPa

30

0.2381 mm

31.9735 MPa

26.8477 MPa

40

0.2381 mm

31.9735 MPa

26.8477 MPa

Using different series terms to calculate deflection and stress. Under working stress, calculate the deflection of the single arm wing plate using formula (4) to be 0.76mm and the stress value to be 15.6MPa.

4 Finite Element Analysis of Telescopic Arm Structure According to the deformation cloud Fig. 4, the maximum deformation displacement of the telescopic arm occurs at the head of the second arm, with a value of w = 1.4mm. According to the equivalent stress Fig. 5, it can be known that the maximum equivalent stress of the telescopic arm is 118.8MPa. The maximum stress of the basic arm is 14.3MPa, the maximum stress of the basic arm is 57.8MPa, and the maximum stress of the second arm is 46.6 MPa.

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Fig. 4. Total deformation

Fig. 5. Equivalent stress

5 Conclusions This article provides the deflection equation and stress equation of the local area of the wing plate during the operation of the telescopic arm. And a finite element analysis was conducted on the telescopic arm. Taking the basic arm wing plate as an example, the calculated deflection value differs by 0.16mm from the finite element analysis results; The difference between the calculated stress values and the finite element analysis results

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is 10.3%, indicating that the stress equation and deflection equation given in this article have certain effectiveness. Acknowledgements. This research is supported by The Technology Innovation Leading Program of Shaanxi Province (No.2020QFY03-04 and No.2020QFY03-08).

References 1. Xiao, L.B., He, L., et al.: Optimum design of loading arm support for packing goods handling machine. J. Shandong Univ. Technol. (Natural Science Edition) 35(06), 81–86 (2021) 2. Mile, S., Milomir, G., Goran, P., et al.: Stress analysis in contact zone between the segments of telescopic booms of hydraulic truck cranes. Thin-Walled Struct. 85, 332–340 (2014) 3. He, X.T., Chen, Q., Sun, J.Y., et al.: Application of the kirchhoff hypothesis to bending thin plates with different moduli in tension and compression. J. Mech. Mater. Struct. 5(5), 755–769 (2010) 4. Li, M., Li, Y.L., Chen, W.M.: Discussion on limitation of virtual displacement in unit-load method. Mech. Eng. 44(02), 368–372 (2022) 5. Kaur, I., Lata, P., Singh, K.: Forced flexural vibrations in a thin nonlocal rectangular plate with Kirchhoff’s thin plate theory. Int. J. Struct. Stab. Dyn. 20(09), 17–24 (2020) 6. Chen, M., Zhang, Q., Ge, Y., et al.: Dynamic analysis of an over-constrained parallel mechanism with the principle of virtual work. Math. Comput. Model. Dyn. Syst. 27(01), 347–372 (2021) 7. Koo, B., Chang, S.M., Kang, S.H.: Natural mode analysis of a telescopic boom system with multiple sections using the Rayleigh-Ritz method. J. Mech. Sci. Technol. 32(4), 1677–1684 (2018) 8. Song, J.W.: Application of Generalized displacement principle to solve the bending problem of rectangular plates with large deflection. YanShan University 24–31 (2017) 9. Xu, G.N., Liu, J., Zhang, G.: Reliability design of crane lattice Jib based on response surface method. Appl. Mech. Mater. 3634(687), 243–248 (2014) 10. Xie, Y., Zhang, L., Tang, Y.M, et al.: Dynamic characteristics of the telescopic boom considering the section deformation. J. Mech. Electr. Eng. 38(01), 49–54+68 (2021)

Printing and Packaging Materials

Study to Optimize the Process and Properties of Celery- Based Wrapping Paper Based on Response Surface Methodology Xue Gong, Jiang Chang(B) , Danting Li, Yinglei Zhang, and Lida Hou College of Light Industry, Harbin University of Commerce, Harbin 150028, Heilongjiang, China [email protected]

Abstract. In order to reduce the environmental pressure brought by traditional packaging materials, countries around the world based on environmental protection, actively improve the product packaging mode, looking for green packaging materials, to create a road of sustainable development. Vegetable based degradable paper packaging materials choose celery as the base material, through pretreatment, cutting hot drift, cooling pulp, adding additives, mixing paper, molding drying and other methods to prepare celery packaging paper. The appropriate plasticizer sorbitol (4% ~ 6%) glycerol (2% ~ 4%) and binder konjac gum (1% ~ 1.5%) were selected, Through compound optimization experiments using the Design-Expert 12.0 system, Analyzing the significant effect of the interaction of additives on the properties of celery paper, When with sorbitol 6.0%, Glycerol, 4.0%, When konjac gum 1.25% was used as a mixed additive, The shock strength of the prepared celery-based wrapping paper was 0.700J, The prepared paper was also compared with the newspaper, A4 paper, the results show that, Celery-based wrapping paper is better than newspaper and close to A4 paper, Therefore, it has certain research significance and feasibility. Through the experimental study of celery-based packaging paper, the research necessity of new packaging materials is determined, and the best preparation process of vegetable packaging paper is found, which provides a certain reference direction for the development of green packaging materials. Keywords: Celery · Vegetable paper · Degradable · Packaging materia · Mechanical properties

1 Introduction With the acceleration of urbanization and the rapid gathering of population, China’s packaging industry has developed rapidly, and China has become the top world packaging power [1–3]. However, due to the low recycling rate of packaging products, packaging waste has increased sharply, and “white pollution” is increasingly serious [4, 5]. In the future, biodegradable packaging materials will become the inevitable trend of green packaging materials. According to statistics, China’s annual vegetable output accounts for more than 25% of the global total output. In 2020, China’s vegetable planting area © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 331–341, 2024. https://doi.org/10.1007/978-981-99-9955-2_43

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has exceeded 30 million hectares, and the annual output is nearly 800 million tons, up 1.7% year on year, ranking first in the world [6–8]. China is a big country in vegetable production and marketing, but in China, most vegetables are sold as fresh food, and its deep processing products are very few. Every year, nearly 30% of fresh vegetables due to no timely sales and processing [9]. In recent years, paper packaging materials based on vegetables are quietly rising, and gradually entered people’s vision. Tang Huimin et al. [10]Using sweet corn and broccoli as experimental raw materials, carrageenan, sodium alginate and starch developed compound vegetable paper for binder, and found the best production process parameters of broccoli-sweet corn compound vegetable paper; Qin Yuhua et al. [11]With carrot, spinach as raw materials, sodium alginate, gelatin, starch as thickening agent, prepare compound vegetable paper. In order to improve the quality and performance of vegetable paper, researchers conducted experimental research on one or certain characteristics, such as Hu Yufeng [12]With celery as the substrate, carboxymethyl cellulose (CMC), gelatin and sodium alginate as binder, glycerol and sorbitol as plasticizer, make edible vegetable paper and determine the folding resistance of vegetable paper, find out the additive mixing ratio of vegetable paper when the extreme value; Sui Ming et al.[13]People took lotus white and konjac as the base material of edible vegetable paper, and sweet potato starch, vegetable paper made of carboxymethyl cellulose sodium (CMC-Na) and xanthan gum were added, and the relevant performance indicators were determined. To sum up, the development of biodegradable vegetable packaging paper has profound significance for environmental protection and social civilization, and can effectively reduce the environmental pollution brought by packaging waste, so as to relieve environmental pressure, improve the utilization rate of vegetables in China, and meet the requirements of human sustainable development [14, 15].

2 Experimental Preparation and Methods 2.1 Experimental Preparation In the experiment, the experimental substrate is celery with a wide range of sources, and the use of single factor experiment to study the influence of different amounts of plasticizer and binder on the properties of celery paper. However, due to the limited experimental time and laboratory conditions, the main indexes measured in this experiment mainly include folding tolerance, fracture elongation, tensile strength and impact resistance strength. Experimental Raw Materials and Reagents. Celery with long fiber, high fiber content and high water content of Harbin University of Commerce was selected as the experimental object; other experimental reagents are shown in Table 1. Experimental Instruments and Equipment. The equipment related to celery paper preparation and performance test are shown in Table 2.

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Table 1. Experimental reagents reagent

attribute

manufacturer

3% Hydrogen peroxide

AR

Guangzhou Zhencui Quality Inspection and Technical Service Co., LTD

Glycerol (Propanicolol)

AR

Kenino Trading, Ltd

sorbic alcohol

AR

Kenino Trading, Ltd

Konjac glue

AR

Kenino Trading, Ltd

algin

CP

Kenino Trading, Ltd

Table 2. Experimental equipment Equipment

Manufacturer

Little Bear utility juicer

Little Bear Hunan Electrical Appliance Factory

ZQ-990 microcomputer control electronic universal testing machine

Dongguan Intelligent Precision Instrument Co., LTD

High-precision digital electronic scale

Kaifeng Group Co., Ltd

BYS-3 temperature and humidity automatic controller

Dongguan Kerui Instrument Co., LTD

Hot air, constant temperature, drum and air drying box

Zhongshan Sanyi Catering Equipment Co., LTD

Digital constant temperature water bath

Shanghai Lichen Instrument Technology Co., LTD

JH-NZY-02 Schoell’s folding tolerance tester

Taicang Jinghua Equipment Co., LTD

CBM-3 thin-film impact testing machine

Beijing Guanzhong Test Precision Electric Equipment Co., LTD

2.2 Experimental Method The test of the performance index of celery paper mainly includes thickness, quantification, folding resistance, tensile strength, fracture elongation and impact strength. Failure Tolerance. Failure resistance refers to the number of folding times of the paper when folding back and forth under certain conditions, expressed as the number of times. The measurement method is to use the folding resistance tester for measurement [16]. Tensile Strength. The degradable vegetable wrapping paper per unit area in Mpa before being pulled by the stretching machine, according to GB 13022–91 test method, its expression is: Ts =

F A

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In the formula: F— material maximum tension at fracture, N; A−−Sample area, m2 Fracture Elongation. Break elongation is the relative index of the elastic properties and soft properties of celery wrapping paper, characterized by percentage. A larger value of the fracture elongation rate indicates a better performance [17]. E=

L1 − L0 L0

In formula: L 1 — Length of the sample at fracture, mm; Impact Strength. Impact strength is an index to judge the toughness and impact resistance of the degradable vegetable packaging paper. Under the action of impact load, the energy absorbed per unit area when the degradable vegetable packaging paper is broken [18]. According to the measurement standard of GB 1943–2007.

3 Experimental Results and Analysis 3.1 Effect of Mass Fraction of Konjac Gum on the Properties of Celery Wrapping Paper According to the single-factor experimental design scheme, the influence of konjac gum on the performance of celery wrapping paper was determined by the performance index as shown in Table 3. Table 3. Effect of konjac gum content on the performance of degradable vegetable wrapping paper metric

Additive amount (%) 0.5

Folding 10.000 ± 0.100 resistance (times) Tensile Strength (MPa)

1.0 8.000 ± 0.080

1.5 5.000 ± 0.090

2.0 5.000 ± 0.120

2.5 3.000 ± 0.130

52.290 ± 0.400 59.470 ± 0.600 73.430 ± 0.500 55.620 ± 0.800 37.710 ± 0.700

Elongation at break (%)

2.630 ± 0.060

3.990 ± 0.080

4.410 ± 0.070

5.970 ± 0.050

3.820 ± 0.060

Impact strength (J)

0.675 ± 0.001

0.725 ± 0.001

0.700 ± 0.002

0.700 ± 0.001

0.675 ± 0.002

It can be seen from Table 3, paper tensile strength, fracture elongation, and impact strength with the increase of konjac add increase after decrease, folding resistance is gradually reduced, mainly due to the konjac gel characteristics, makes the molecular interaction force, with the increase of the amount of konjac add, lead to paper hard

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brittleness increases, so the tensile strength of paper is reduced. When the amount of konjac gum added is 0.5% ~ 1.5%, the impact strength increases with the increase of the additive content, This is because konjac gum can improve the toughness of vegetable paper. With the continuous increase of the amount added, in the process of 1.5% ~ 2.5%, the binding strength of paper molecules is reduced, and the brittleness of paper increases, resulting in the weakening of impact resistance. In conclusion, the maximum resistance of konjac gum is 10 times at 0.5%, the maximum tensile strength of konjac gum at 1.5%, the maximum elongation at 4.41% and 0.725J at 1.0%. Analysis, the maximum amount of konjac gum is 1.0% at 1.0% to 1.5%. 3.2 Sodium Alginate, Quality Fraction Effect on the Performance of Celery Paper According to the one-factor experimental design scheme, the effect of sodium alginate on the performance of celery wrapping paper was obtained by measuring the performance index is shown in Table 4. Table 4. Effect of sodium alginate content on the performance of degradable vegetable packaging paper metric

Additive amount (%) 0.5

Folding resistance (times) Tensile Strength (MPa)

1.0

8.000 ± 0.080 10.000 ± 0.100

1.5 6.000 ± 0.090

2.0 4.000 ± 0.120

2.5 4.000 ± 0.110

43.010 ± 0.800 63.070 ± 0.600 50.290 ± 0.700 47.830 ± 0.800 30.430 ± 0.600

Elongation at break (%)

1.790 ± 0.030

2.820 ± 0.060

4.050 ± 0.040

3.710 ± 0.030

2.690 ± 0.050

Impact strength (J)

0.650 ± 0.002

0.675 ± 0.001

0.700 ± 0.002

0.675 ± 0.001

0.625 ± 0.001

As seen from Table 4, the folding resistance, fracture elongation, tensile strength and impact strength of celery packaging paper decreases with the increase of sodium alginate. When the amount of sodium alginate is 0.5% ~ 1%, due to the gel characteristics and molecular structure, the bond and group of sodium alginate and the vegetable fiber molecules increase. As the concentration of sodium alginate increases, the binding strength of the paper molecules decreases, resulting to the weakening of impact resistance.

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In conclusion, the maximum bending resistance of sodium alginate was 10 times at 1.0%, 1.0%, the maximum tensile strength was 63.07 Mpa at 1.0%, 4.05% break elongation at 1.5%, and the maximum impact strength was 0.700J. After analysis, the maximum adding amount of sodium alginate was 0.5% ~ 1.5% The experimental results show that konjac gum has a better effect on paper, so the binder is used in the composite experiment, and the best effect range is 1% ~ 1.5%.

4 Celery-Based Wrapping Paper Preparation Process, Parameter Optimization 4.1 Experimental Design Appropriate amount of plasticizer can keep the paper soft and elastic, and the role of the binder is to make the fiber structure inside the celery paper more uniform and tight. Celery wrapping paper need all aspects of mechanical properties are conform to the conditions, which requires the preparation process need to add plasticizer and binder at the same time, the two kinds of additive mixed use can improve the packaging properties of celery paper, so through the complementary effect between the two, the additive compound to the optimal proportion to meet the requirements of celery paper. Factor-level Table. The experiment has three factors and three levels, namely sorbitol 4% ~ 6%, glycerol 2% ~ 4%, and konjac gum 1% ~ 1.5%, as shown in Table 5.

Table 5. A factor level table Horizontal

Factor X1 Sorbitol (%)

X2 Glycerol (%)

X3 Konjac Gum(%)

1

4

2

1

2

5

3

1.25

3

6

4

1.5

Experiment Arrangement and Results. After the above one-factor experiments and the comparative analysis results, the amount of glycerol and sorbitol were taken as the independent variables, and the impact strength as the dependent variable. Experiments were designed with the Design-Expert12.0.0 system with specific experiment arrangements shown in Table 6.

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Table 6. Experiment arrangement and results Order number

Sorbitol addition (%)

Glycerol addition (%)

Additive amount of konjac gum (%)

Impact strength (J)

X1

X2

X3

Y

1

4

2

1.25

0.600 ± 0.01

2

6

2

1.25

0.675 ± 0.03

3

4

4

1.25

0.625 ± 0.01

4

6

4

1.25

0.700 ± 0.02

5

4

3

1.00

0.625 ± 0.01

6

6

3

1.00

0.725 ± 0.03

7

4

3

1.50

0.675 ± 0.02

8

6

3

1.50

0.725 ± 0.01

9

5

2

1.00

0.625 ± 0.04

10

5

4

1.00

0.675 ± 0.02

11

5

2

1.50

0.675 ± 0.03

12

5

4

1.50

0.750 ± 0.02

13

5

3

1.25

0.675 ± 0.01

14

5

3

1.25

0.675 ± 0.03

15

5

3

1.25

0.675 ± 0.02

16

5

3

1.25

0.700 ± 0.03

17

5

3

1.25

0.675 ± 0.01

4.2 Response Surface Analysis of the Influence of Composite Additives on the Impact Strength of Degradable Vegetable Wrapping Paper Response surface analysis with the software Design-E xpert 12.0 yielded the impact strength (Y) and sorbitol, and the added amount (X1 ). The amount of glycerol added (X2 ), Konjac gum (X3 ) of the quadratic polynomial response regression equation. Y = 0.68 + 0.0375X1 + 0.0156X2 + 0.0156X3 − 0.0125X1 X3 − 0.0063X2 X3 − 0.0056X12 − 0.0244X22 + 0.0131X32 The significance analysis of the variable factors of the additive in the regression equation is shown in Table 7. Analysis from the above table data, the quadratic response model for impact intensity is significant, where X3 、X2 2 0.01 < P < 0.05, significant; X1 、X2 P < 0.01, which is extremely significant; the observation table shows that the mismatch P > 0.05, therefore not significant, indicates that the model is stable and predicts the actual change well. Of this model, the correlation coefficient is given in R2 = 0.9238 approaches 1, indicating

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X. Gong et al. Table 7. Analysis of variance of experimental results of impact strength

Source of variance

Sum

Free degree

Mean square

F price

P price

Conspicuousness

model

0.0257

9

0.0029

9.42

0.0037

notable

X 1 -sorbic alcohol

0.0112

1

0.0112

41.31

0.0004

notable

X 2 -glycerol

0.0038

1

0.0038

14.06

0.0072

notable

X 3 -Konjac glue

0.0038

1

0.0038

14.06

0.0072

notable

X 1X 2

0.0025

1

0.0025

5.05

0.0595

quiet

X 1X 3

0.0006

1

0.0006

2.3

0.1736

quiet

X 2X 3

0.0002

1

0.0002

0.5738

0.4735

quiet

X 12

0.0006

1

0.0006

2.18

0.1833

quiet

X 22 X 32

0.0014

1

0.0014

5.08

0.0589

quiet

0.0016

1

0.0016

5.8

0.0468

notable

residual

0.0019

7

0.0003

-

-

-

Unplanned item

0.0014

3

0.0005

3.75

0.1171

quiet

pure error

0.0005

4

0.0001

-

-

-

sum

0.0276

16

-

-

-

-

high confidence in the model equation and high fit of the measured and predicted impact strengths.noise-signal ratio Ade q = 8.24 > 4, indicating that the model can be used to predict, and the response surface and contour lines under the model are shown in Fig. 1. As can be seen from Fig. 1, the surfaces are steep, so it can be judged that the compound additive has a significant impact on the impact strength of celery paper. The two-dimensional contour diagram shows the influence of sorbitol, glycerol and konjac gum. It can be observed that in the interaction between glycerol and konjac gum, the contour is nearly oval, which indicates that the influence on the impact strength is obvious; when sorbitol and glycerol interact, the shape of the contour is similar to the circle, so the influence on the impact strength is small. As can be seen from the response surface analysis chart, the maximum value of impact intensity was 0.750J, when sorbitol added 5%, glycerol added 4%, and konjac gum added 1.5%. Determination of the Optimal Process Parameters. According to data analysis by Design-Expert 12 system, the optimal ratio of additive was 6.0% sorbitol, 4.0% glycerol and konjac gum 1.25%. At this time, the comprehensive performance of the paper was better, hygroscopic 260 g / (m2 · 24 h), folding resistance of 100 times, tensile strength of 64.39 MPa, fracture elongation of 8.01%, and impact strength of 0.70J.

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(A) Sorbitol and glycerol

(B) Sorbitol and konjac gum

Fig. 1. Effect of the interaction of the compound additive on the impact strength of celery-based wrapping paper.

4.3 Performance Comparison of Different Papers The performance parameters of A4 paper and newspaper were tested, and the feasibility of celery paper was analyzed. The specific data are shown in Table 8. It can be seen from Table.11 that the performance parameters of biodegradable vegetable wrapping paper are significantly higher than those of newspapers. Compared with A4 paper, biodegradable celery wrapping paper has high hygroabsorption, folding resistance and fracture elongation, and its tensile strength and impact strength are low, but relatively close, so it has certain research significance and feasibility.

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(C) Glycerol and konjac gum

Fig. 1. (continued)

Table 8. Performance data for different papers Paper type

Moisture absorption [g/(m2 ·24h)]

Folding resistance (times)

Tensile Strength (MPa)

Elongation at break (%)

Impact strength (J)

Celery wrapping paper

260

100

64.39

8.01

0.70

A4paper

206

90

92.21

3.35

0.80

newspaper

130

74

26.14

1.91

0.65

5

Conclusion

With celery as the main base material, adhesive, plasticizer as the main additive to prepare celery packaging paper, through the analysis of the influence of various additives on the mechanical properties of celery paper and its degradability. Through the analysis of pulp, slurry water content and drying temperature on the influence of paper performance and the required performance of the test method, determine the appropriate concentration range of all kinds of additives, select konjac gum, glycerin, sorbitol for additive optimization experiment, through the analysis of the influence of additive concentration on celery paper interaction, finally get the optimal additive proportion range, to get better packaging performance of celery paper, for our country vegetable processing and new industrial paper development and application provides an effective way.

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References 1. Chen, T., Jiang, G., Zhang, D.: Current situation research and Prospect of other Biodegradable Packaging Materials. Plastics Indus. 48(1) 2020 2. Zhou, H.: Research and application status of green packaging materials. Inf. Record. Mater. 19(4), 12–13 (2018) 3. Cao, L., Yu, Z.: Research Progress of edible Packaging Film. Packag. Food Mach. 33(4), 50–54 (2015) 4. Wang, Z., Ding, S., Yang, L.: Research and development of degradable PLA acid membrane. Shandong Textile Technol. 3, 20–22 (2016) 5. Vahid, G., Iman, S.G.: Photo-producible and photo-degradable starch/TiO2 bionanocomposite as a food packaging material: development and characterization. Int. J. Biol. Macromol. 106, 661–669 (2017) 6. Dilkes-Hoffman, L.S., Lane, J.L., Grant, T., et al.: Environmental impact of biodegradable food packaging when considering food waste. Cleaner Prod. 180, 325–334 (2018) 7. Mc Hugh, T.H., Olsen, C.W., Olson, D.A.: New technologies in fruit and vegetable processing in proceedings of the United States-Japan cooperative program in natural resources. Food Agricult. Panel 3, 430–436 (2004) 8. Pan, Z., Olson, D.A., Ameratanga, K.: Feasibility of using infrared heating for blanching and dehydration of fruits and vegetables. Am. Soc. Agricult. Eng. Meetings Papers. ASAE Paper 2005, 1–13 (2005) 9. Ying, Z., Hana, H., Suyu, L., et al.: Progress in vegetable paper. Agricult. Products Process. 3, 68–70 (2010) 10. Tang, H., Shang, H.: Development of broccoli sweet corn compound vegetable paper. Food Res. Develop. 36(23), 56–59 (2015) 11. Qin, Y., Hang, Y., Feng, R.Y.: Other carrot-spinach compound vegetable paper development. Agricult. Products Process. 17, 10–12 (2018) 12. Hu, Y., Gong, X., Liu, X., et al.: Effect of additives on the folding tolerance of edible vegetable paper. Packaging Eng. 39(11), 54–59 (2018) 13. Sui, M., Wei, M.: Research on the production process of konjac substrate edible vegetable packaging paper. Food Res. Develop. 38(08), 89–91 (2017) 14. Liao, H., Li, J., He, Z.: Progress in the production process of vegetable paper. Food Mach. 06 2003 15. Du, C.: Heilongjiang Paper-making 45(03), 20–22 (2017) 16. Xu, X.: Research on the life cycle and environmental impact assessment of coated white paper products. Modern Agricult. Sci. Technol. 21, 2011 17. Li, N., Chen, S., Wu, J.: The enzymatic preparation of modified maltodextrin and its application in baking products. Food Ferment. Industry. https://doi.org/10.13995/j.cnki.11-1802/ ts.027726

Study on the Adhesion of UV Ink in Tinplate Printing Zhenxing Wu(B) and Zhen Wei School of Media Design, Tianjin Modern Vocational Technology College, Tianjin, China [email protected]

Abstract. With the development of the national economy, residents’ purchasing power continues to increase, and people’s demand for various colorful metal packaging is increasing year by year. UV ink has been favored by people for its instant drying, high efficiency, low cost, environment-friendly and many other advantages. However, in actual production, some printing plants are subjected to many restrictions and using a varnishing machine that is not in the same workshop as the printing press for offline varnishing. This causes friction in the process of stacking and handling, and ink loss occurs. Through theoretical analysis and practical production experience, this paper designs the experimental UV ink formula, selects polyester acrylate, aliphatic polyurethane diacrylate and hyperbranched urethane acrylate as prepolymers in the formula, and changes the amount of polyester acrylate and aliphatic polyurethane diacrylate in yellow, magenta, cyan and black inks according to the proportion of 5% of the overall formula, and according to the respective characteristics of the four-color ink. A certain amount of hyperbranched urethane acrylate is added separately to speed up the reaction rate of the UV curing system. Through the adhesion test of the printing sample, the optimal color sample of the four-color ink is selected, so as to optimize the UV ink formula and explore and solve the problems in the production of the printing plant. Keywords: UV ink · Tinplate · Adhesion

1 Introduction Ultraviolet curable ink (referred to as UV ink) has received extensive attention from scientific research institutions and manufacturers in various industries for its advantages such as curing at room temperature, short start-up cycle, instant drying, high productivity, stable film-forming performance, low production cost, low energy consumption, space saving, zero VOCs emissions and environmental friendliness. Compared with the traditional thermosetting iron printing process, the UV iron printing process is more in line with the national food safety and environmental protection strategy due to its advantages of low energy consumption, zero VOCs emissions and inherent environmental friendliness [1]. The application of UV ink on metal sheets with non-permeable bodies immediately attracted attention. Yin Wenke designed a UV offset printing iron ink and applied for a patent. Zhang Nengzhi developed a UV printing iron ink, which not © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 342–351, 2024. https://doi.org/10.1007/978-981-99-9955-2_44

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only has the printability of lithographic offset printing ink, but also has heat resistance, solvent resistance, machinability resistance, good ultraviolet curing performance and storage stability. Huo Cui prepared UV ink for hybrid LED aluminum substrate, and studied the comprehensive performance of the ink film after curing. However, most of the metal packaging and printing enterprises in China are small scale enterprises, due to the limitations of site, equipment, printing process technology and personnel, frictions and ink loss occur during stacking and transporting the printed tinplate, which cannot meet the development requirements of “prepress digital networking, printing multi-color continuous and efficient, post-press diversified automation” in the field of international printing iron, resulting in printing enterprises requiring UV ink to have higher adhesion [2]. This paper focuses on the adhesion of UV ink on coated tinplate by optimizing the UV ink formulation.

2 Preparation of UV Inks 2.1 Experimental Raw Materials and Experimental Instruments Experimental Materials 1) Prepolymer (light-curing resin). The prepolymers selected for this experiment are DOUBLEMER®236-1, DOUBLEMER®5900 and DOUBLEMER®2015 purchased from Double Bond Chemical (Shanghai) Co., Ltd. ➀DOUBLEMER®236-1 DOUBLEMER®236-1 is a polyester acrylate oligomer mixed with 20% TMPTA and 10% TMP3EOTA monomer. Its Gardner chromaticity is 5 max, the viscosity at 25 °C is 200–300 Pa.s, the acid value is 25 mg KOH/g, and the density is 1.28 g/cm3 . ➁DOUBLEMER®5900 DOUBLEMER 5900 is an IBOA mono that is made of aliphatic polyurethane diacrylate dissolved in oligomers 25%.Body acquisition. It contains 2 functional groups and is a Gardner clear liquid with a color of 2 max and a viscosity of approximately 100 Pa.s at 25 °C. ➂DOUBLEMER®2015 DOUBLEMER®2015 is an acrylate oligomer containing 19 functional groups with a molecular weight of 3026, acid value < 1mg KOH/g, light yellow liquid, viscosity at 25 °C is 0.6–0.7 Pa.s. 2) Photoinitiators The photoinitiators selected for this experiment are Irgacure®907, Irgacure®819 and Irgacure®184 from BASF AG in Germany. ➀Irgacure®907 Irgacure®907, molecular formula is C15 H21 NO2 S, appearance is white to yellowish powder, molecular weight is 279.40, density is 1.2 g/cm3 , The main absorption wavelengths are 230 nm and 304 nm.

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➁Irgacure®819 Irgacure®819, molecular formula is C26 H27 O3 P, the appearance is yellow powder, the molecular weight is 418.5, the density is 1.2 g/cm3 , and the main absorption wavelengths are 295 nm and 370 nm. ➂Irgacure®184 Irgacure®184, Chinese name is 1-hydroxycyclohexylphenyl ketone, molecular formula is C13 H16 O2 , appearance is white to off-white crystalline powder, molecular weight is 204.3, density is 1.18 g/cm3 , main absorption wavelengths are 246 nm, 280 nm and 333 nm. 3) Pigments The pigments selected for this experiment were benzidine yellow, pigment red, phthalocyanine blue BGS and carbon black. 4) Dispersant The dispersant used in this experiment is BYK-168 wetting and dispersing from BYK AG in Germany, with an amine value of 10.5 KOH/g and a density of 1.10 g/cm3 at 20 °C. 5) Antioxidants The antioxidant used in this experiment is CHINOX®1010 from Double Bond Chemical (Shanghai) Co., Ltd. The molecular formula is C73H108O12, the molecular weight is 1178, and at 20 °C, the density is 1.116 g/cm3, and the appearance is white crystalline powder. 2.2 Experimental Methods The preparation process of UV ink is achieved by grinding and crushing large particles into tiny particles through the shear stress between the three rollers of the three-roller mill, and uniformly dispersing the pigment particles in other mixed components. This is a physical process, a dispersion of pigment particles, and a homogeneous mixing of components in the ink.

3 Preparation of Printed Samples 3.1 Experimental Raw Materials and Experimental Instruments Experimental Raw Materials. UV inks; Coated tinplate: Polyester-coated tinplate is pre-coated and cut to 40 mm × 270 mm size. Experimental Equipment. IGT Printability Tester: IGT Printability Tester with printing disc and string roller suitable for UV ink, model C1-5, printing disc and homogenization roller are rubber rollers, printing size 35 mm × 210 mm, IGT (Netherlands) Printing Test Systems GmbH.

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3.2 Experimental Methods IGT Printability Tester can comprehensively determine the printing performance of UV inks by setting specific conditions. In this experiment, a IGT Printability Tester was used to simulate a printing pressure of 600 N, and UV ink was used to sample on the coated tinplate. The experimental ambient temperature was 25 °C and the relative humidity was 60%.

4 Measurement of Adhesion of UV Ink on Coated Tinplate 4.1 Experimental Raw Materials and Experimental Instruments Experimental Raw Materials. Printed samples prepared by Sect. 2 “Preparation of printed samples”. Experimental Instruments. Paint film scriber: QFH paint film scriber with multiedged cutting knife, multi-edge cutting knife has a total of 11 blades, the blade spacing is 1 + 0.01 mm, with wingers; 3M tape: width 24 mm. 4.2 Experimental Methods The purpose of this experiment was to measure the adhesion of the prepared UV ink on the coated tinplate with an ambient temperature of 25 °C and a relative humidity of 60%, and record the adhesion level of the printed sample according to the adhesion grade evaluation method in “Test Method for Measuring Adhesion with Tape” (ASTM D3359-2002).

5 Results and Discussion 5.1 Analysis of Printed Samples The prepared UV ink is proofed and cured using an IGT printing suitability. First, the degree of curing of the printed sample can be visually evaluated by finger touch [3]. Place the printed sample flat on the operating table, the printing side up, touch the cured ink film, and there is no sticky feeling. Then, press and rotate with your thumb to twist the ink film. All printed samples were twisted by the thumb without cracking or ink loss. This proves that all printed samples have been cured. Secondly, the surface topography of all printed samples was visually evaluated. Yellow and magenta ink film is flatter, smoother, while cyan and black ink film has fine particles, and annular white spots caused by these fine particles. Among them, the cyan sample ink film is more obvious than the black color sample ink film, as shown in Figs. 1, 2, 3 and 4. This is consistent with the measurement of ink fineness: yellow and magenta inks have less fineness, while cyan and black inks have greater fineness, and cyan inks have more particles above the scale value. This can also be attributed to the large viscosity of cyan ink, which introduces some fine impurities from the outside world into the preparation of the printed sample. The number of rolls in the homogenization system of the printability meter is much less than the number of rolls of the printing machine, and due to the short ink path, there is not enough shear stress and shear process to break up the fine particles.

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Fig. 1. Printed samples of Yellow ink

Fig. 2. Printed samples of Magenta ink

Fig. 3. Printed samples of Cyan ink

Fig. 4. Printed samples of Black ink

5.2 UV Ink Adhesion Analysis UV inks are increasingly used on non-absorbent materials such as plastics, glass and metal sheets, ink films Adhesion is an important indicator for evaluating the quality of UV inks. Only with a certain adhesion, the ink film can adhere well to the surface of the substrate, so that the UV ink plays a good decorative role. The factors influencing adhesion include both external and internal factors. External factors include the temperature and humidity of the environment, the state of machinery and equipment, the level of technology and the quality of personnel, etc., which are generally not easy to change [4]. From the perspective of internal factors, the adhesion of UV ink is mainly affected by its components, and the types and contents of prepolymers, monomers, photoinitiators, pigments and additives will have an impact on the adhesion of the ink [5]. Among them, the most significant influencing factor is the prepolymer, which directly

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determines whether the performance of the ink film after curing meets the requirements of production and use or not. Adhesion is an important characterization of the adhesion between the ink and the substrate, and has a high correlation with the properties of the substrate, the thickness of the ink layer, the temperature and humidity of the environment, and the application and use conditions. Its essence is an interaction force between interfaces, including the cohesion of the ink itself, and the adhesion between the ink and the substrate. These two forces determine the adhesion between the ink layer and the substrate. At the same time, in crosslinked systems, more polar groups may make a positive contribution to adhesion. In this experiment, adhesion tests were performed on all printed samples according to the Test Standard for Measuring Adhesion with Tape (ASTM D3359–02), and the test results were recorded in the following grades: The test results are shown in Table 1. It is generally believed that the adhesion level above 3B is qualified. It was found that all printed samples with an ink volume of 0.075 ml except C1-0.075 had an adhesion grade of 5B and excellent adhesion properties. With the amount of ink being increased, the number of printed samples with qualified adhesion performance showed a decreasing trend. This is because with the increase of the amount of ink, the ink layer becomes thicker, and the ink is easy to embrittlement after the surface curing of tinplate is insufficient or cured into a film, resulting in poor adhesion. With the increase of polyester resin content, the adhesion level of color samples increases. This is due to the increase in the number of flexible segments of polyester, which improves the flexibility of the film layer. Table 1. Adhesion grade of printed samples Color

Level

Color

Level

Color

Level

Color

Level

Y1-0.075

5B

M1-0.075

5B

C1-0.075

3B

K1-0.075

5B

Y1-0.15

0B

M1-0.15

4B

C1-0.15

0B

K1-0.15

0B

Y1-0.3

0B

M1-0.3

1B

C1-0.3

0B

K1-0.3

0B

Y2-0.075

5B

M2-0.075

5B

C2-0.075

5B

K2-0.075

5B

Y2-0.15

5B

M2-0.15

5B

C2-0.15

2B

K2-0.15

0B

Y2-0.3

1B

M2-0.3

3B

C2-0.3

0B

K2-0.3

0B

Y3-0.075

5B

M3-0.075

5B

C3-0.075

5B

K3-0.075

5B

Y3-0.15

5B

M3-0.15

5B

C3-0.15

5B

K3-0.15

4B

Y3-0.3

5B

M3-0.3

5B

C3-0.3

5B

K3-0.3

0B

Y4-0.075

5B

M4-0.075

5B

C4-0.075

5B

K4-0.075

5B

Y4-0.15

5B

M4-0.15

5B

C4-0.15

5B

K4-0.15

4B

Y4-0.3

5B

M4-0.3

5B

C4-0.3

5B

K4-0.3

1B

Y5-0.075

5B

M5-0.075

5B

C5-0.075

5B

K5-0.075

5B

Y5-0.15

5B

M5-0.15

5B

C5-0.15

5B

K5-0.15

5B

Y5-0.3

5B

M5-0.3

B

C5-0.3

5B

K5-0.3

5B

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Yellow UV Ink Adhesion Analysis. Figure 5 shows the adhesion experiment of a yellow printed sample. It can be seen that the ink film of all printed samples is relatively smooth and there are no impurities on the surface. This is related to the small fineness of yellow ink. Through analysis, the thickness of the ink layer of all color samples of yellow ink increased with the increase of the transfer amount, and the transfer amount increased with the increase of the ink load. Among them, Y1 has extremely poor adhesion after the thickness of the ink layer increases, and the adhesion of Y2 at the highest ink layer thickness is also 0B, but the printed samples of the remaining color samples show excellent adhesion in all ink layer thicknesses. This can be attributed to the lack of Y1 and Y2 polyester soft segments, which do not give the ink film sufficient flexibility, and during the polymerization process, the volume of the ink film shrinks and the internal stress increases. In the case of low ink thickness, Y1 and Y2 show excellent adhesion, which is due to the thinner ink layer, increased transparency, and high degree of light curing, which promotes adhesion to the substrate. Moreover, the ink layer is thinner, which reduces the shrinkage of the ink layer during the curing process, reduces the internal stress of the ink layer, and enhances the adhesion. Combined with the flow properties, rheological properties, transfer properties and price factors of the five color samples of yellow ink, Y3 was selected as the optimal color sample of yellow UV ink in this paper.

Fig. 5. Adhesion test of Yellow printed samples

Magenta UV Ink Adhesion Analysis. Figure 6 shows the adhesion experiment for a magenta printed sample. The ink film of the magenta printing sample is also relatively flat and smooth, because it has a good flow value, and the viscosity and viscosity are low, which is conducive to spreading. However, because the amount of pigment added is higher than that of yellow ink, the solid content in the system increases, resulting in lower transfer performance than that of yellow ink, which may also be related to its thixotropy. Except for M5–0.3, the ink thickness of the other printed samples is low, coupled with its slightly higher photoinitiator addition, which makes the curing degree of magenta UV ink generally improved and the overall adhesion performance. Since the adhesion class of M3, M4 and M5 is 5B at the three inking amounts, M5 was selected as the optimal color sample for the magenta UV ink by comparing the transfer properties, fluidity and rheological behavior of the three color samples.

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Fig. 6. Adhesion test of Magenta printed samples

Cyan UV Ink Adhesion Analysis. Figure 7 is an adhesion experiment for a cyan printed sample. Since the cyan pigment has the worst dispersion during the preparation of UV ink, the fineness of the cyan ink is large, and there are particles in the color area of the printed sample surface. This can be attributed to insufficient shear force, which does not completely break up the large-sized pigment particles, or to the high viscosity of the ink, which introduces impurities from the outside. The overall adhesion of C1 and C2 is not good, which is due to insufficient amount of polyester resin, the formation of a sufficient number of hydrogen bonds with the coating on the surface of the tinplate, the destruction of the force between the ink film and the substrate after the application of external force, and the scattering effect of the ink layer on ultraviolet rays due to the large fineness, thereby reducing the initiation efficiency of the photoinitiator and insufficient curing [6]. Comparing the flow properties and rheological behavior of C3, C4 and C5, it was found that C4 had the highest flow value, lower viscosity and lowest viscosity among cyan ink samples. Moreover, because of its excellent thixotropic performance, it has relatively good transfer performance. Therefore, C4 is preferred as the optimal color sample of cyan UV ink in this paper. Black UV Ink Adhesion Analysis. Figure 8 shows the adhesion experiment for a black printed sample. Carbon black is a typical light-absorbing material that absorbs photons, resulting in fewer photons absorbed by the photoinitiator and reducing the initiation efficiency of the photoinitiator. At the same time, the free radicals generated by the photoinitiator in the curing system are captured or inactivated, reducing the degree of curing of the ink layer. In this experiment, only the printed sample of K5 showed excellent adhesion on all ink thicknesses. The adhesion of the remaining color samples only reached 5B grade on the thickness of the low ink layer, and was poor in the thickness of the high ink layer, which was related to the insufficient amount of polyester resin, the light absorption and radical scavenging characteristics of carbon black, and the addition of a large amount of hyperbranched polymer. However, with the increase of polyester resin, a sufficient number of hydrogen bonds are formed between the ink film and the

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Fig. 7. Adhesion test of Cyan printed samples

substrate surface coating to increase the firmness, and with the increase of soft chain segments, the flexibility of the ink film is improved, and the adhesion performance is gradually improved. Therefore, K5 is preferred as the optimal color sample for the black UV ink in this paper.

Fig. 8. Adhesion test of Black printed samples

6 Conclusion In this paper, the formulation of UV ink for experimental use is designed through theoretical analysis and practical production experience. Polyester acrylates, aliphatic polyurethane diacrylates and hyperbranched urethane acrylates were selected as prepolymers in the formulation. The amount of polyester acrylate and aliphatic polyurethane diacrylate added to yellow, magenta, cyan and black inks is changed according to the ratio of 5% of the overall formula, but the total proportion of the two in the formula remains unchanged. According to the characteristics of the four color inks, a certain amount of hyperbranched urethane acrylate is added to accelerate the reaction rate of the UV curing system and harmonize the flow properties, including flow value, adhesion and viscosity. Three different photoinitiators were selected and a certain amount was

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added according to their respective initiation characteristics. In the formulation, yellow pigments have a small specific gravity and a large specific surface area, which will affect the flow properties, so the dosage is less. In the four-color ink, a certain amount of wetting and dispersing agent and antioxidant are also added. In this adhesion test of the printing sample, Y3, M5, C4, and K5 are the optimal color samples of the ink color sample. They were selected for the flow properties, rheological behavior and transfer performance of the ink samples.

References 1. Liu, Y.: UV printed iron ink, an environmental pioneer in the metal packaging industry. Screen Print. Indust. 03, 15–16 (2019) 2. Bin, Y.: How to improve the adhesion of UV ink. Printed Today 05, 74–75 (2015) 3. Rongbin, L.: Discussion on food safety of metal packaging UV ink. J. Print. 47(3), 13–15 (2018) 4. Zhang, P., Liu, L., Sun, Li., et al.: Orthogonal study on the effect of epoxy phenolic coating iron printing process on adhesion of tin plate. Hebei Metall. 40(1), 34–37 (2018) 5. Fan, S., Li, H., Yang, L., et al.: Preparation and performance study of UV screen printing Ink. Packag. Eng. 34(03), 120–124 (2013) 6. Macarie, L., Ilia, G.: Influence of pigment properties on UV-curing efficiency. J. Appl. Polymer Sci. 104(1), 247–252 (2007)

Printed Preparation of Cellulose-Based Hydrogel Sensors for Human Motion Detection Haikuo Zhang1,2,3 and Fuqiang Chu1,2,3,4(B) 1 Faculty of Light Industry, Qilu University of Technology (Shandong Academy of Sciences),

Jinan 250353, China [email protected] 2 State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, China 3 Key Laboratory of Green Printing and Packaging Materials and Technology in Universities of Shandong, Faculty of Light Industry, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, China 4 Kiev College, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, China

Abstract. This study aims to prepare gel ink from cellulose, polyvinyl alcohol, and carbon nanotubes, and to prepare hydrogel sensors by direct writing printing and freezing cycle and test their performance. Firstly, TEMPO-oxidized cellulose was prepared by the TEMPO oxidation method, and then PVA and CNT were added to prepare gel ink, The gel sensing film was printed by direct writing, and then the hydrogel sensor that could be used for human motion detection was obtained through the freezing cycle. The degree of stretching of the hydrogel sensor can reach 500%. At 100% stretching, the response time is 180ms and the sensitivity is 1.12. The movement of human elbows, wrists, and knuckles can be very accurately identified. TEMPO oxidizes cellulose and carbon nanotubes to improve cellulose hydrogels’ conductivity and mechanical properties, and direct printing can easily and efficiently print the structure of the prepared sensor. The prepared hydrogel sensor shows high flexibility, high conductivity, and high sensitivity, which can monitor the large and small movements of the human body for a long time and stably, which is of great significance for the preparation and application of subsequent cellulose hydrogel sensors. Keywords: Cellulose · Conductive hydrogels · Flexible sensors · Direct writing printing

1 Introduction Cellulose conductive hydrogels are three-dimensional network gels with high water content formed by chemical or physical crosslinking of cellulose and some conductive materials. Due to its advantages such as excellent electrochemical performance, biocompatibility, 3D printing, and mechanical stability, it plays an important role in many fields, such as electronic skin [1, 2], triboelectric nanogenerators [3, 4], supercapacitors © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 352–358, 2024. https://doi.org/10.1007/978-981-99-9955-2_45

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[5, 6], medical engineering [7], etc. especially in the field of flexible wearable sensors [8, 9]. Flexible sensors based on cellulose conductive hydrogels can convert external strain, temperature, pressure, and other stimuli into internal detectable electrical signals, to sense changes in the external environment and realize real-time detection of the external environment. Attaching a flexible hydrogel sensor to the surface of the human body can realize real-time detection of various human movements [8]. Carbon nanotubes (CNTs) have excellent mechanical and electrochemical properties and are widely used in highcapacity energy storage devices [10], flexible electronic devices [11], conductive hydrogels [12], and other fields [11]. CNT is added to hydrogels, because of its unique structure, high conductivity, excellent electrochemical stability, and good mechanical properties, It can greatly improve the mechanical, electrochemical, and sensing performance of composite hydrogels [13]. In the field of flexible hydrogel sensor preparation, 3D printing technology plays an increasingly important role. Among them, direct writing printing [14] technology has strong two-dimensional and three-dimensional molding capabilities, which can directly print the required structure on a flexible substrate of various materials, with good flexibility, controllability, speed, low cost, and green environmental protection. In this paper, a conductive hydrogel ink was prepared by the one-pot method, and a flexible hydrogel sensor with high flexibility, high conductivity, and high sensitivity was prepared by direct writing printing and freezing cycle. CNT was added as a conductive and mechanically reinforced nanofiller to improve the hydrogel’s mechanical properties and conductivity. At the same time, the addition of TEMPO-oxidized cellulose can not only enhance the mechanical properties of hydrogels but also effectively promote the dispersion of CNTs in the hydrogel network. The prepared gel sensor can make a very accurate identification of the movement of the human elbow, wrist, and knuckles, and can monitor the large and small movements of the human body for a long time and stably.

2 Experimental 2.1 Experimental Materials and Instruments Main Materials. Multi-walled carbon nanotubes (>99.9%), Shanghai Macklin Biochemical Technology Co., Ltd.; Sodium bromide (99.9%), Shanghai Macklin Biochemical Technology Co., Ltd.; Hydrochloric acid (AR), Yantai Far East Fine Chemical Co., Ltd.; Absolute ethanol (AR), Tianjin Fuyu Fine Chemical Co., Ltd.;2,2,6,6,Tetramethylpiperidine-1-oxyradical (98%), Shanghai Maclin Biochemical Technology Co., Ltd.; Chitosan (acetylation degree 98%), Shandong Mingsheng Biotechnology; Glacial acetic acid (AR), Tianjin Gaoyu Fine Chemical Co., Ltd.; Sodium hypochlorite (AR), Yantai Far East Fine Chemical Co., Ltd.; Sodium hydroxide (AR), Sinopharm Chemical Reagent Co., Ltd.; Polyvinyl alcohol (1799), Shanghai Maclin Biochemical Technology Co., Ltd. Main Experimental Instruments. Conductive film tester (JY-DM02), Jinan Jinyuan Environmental Protection Technology Co., Ltd.; Digital Source Table (Keithley2400), Shenzhen Saga Instruments Co., Ltd.; Infrared Spectrometer(NICOLET6700), Thermo

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Fisher Scientific, USA;Automatic high-speed dispensing machine (E5), Nordson Corporation of America; Single channel pipette (F2), Thermo Fisher Scientific Inc.; Electronic Balance (ME204), Teler-TOLEDO Instruments (Shanghai) Co., Ltd.; Collector constant temperature heating magnetic stirrer (DF-101S), Gongyi Yuhua Instrument Co., Ltd.; Vacuum freeze dryer (BDZF-25), Shandong Brocade Scientific Instrument Co., Ltd.; CNC ultrasonic dispersion instrument (KQ-600DE), Guangdong Goode Ultrasound Co., Ltd.

2.2 Experiments Preparation of TEMPO Oxidized Cellulose. First, disperse 1g of absolute cellulose in a beaker containing 0.016g TEMPO and 0.1g NaBr solution, add 6mL of NaClO solution to it, wait for 15min after its reaction, adjust the pH value of the reaction system to 10 with 0.1mol/L Hcl and NaoH until the pH value no longer changes, and terminate the reaction with 5mL of absolute ethanol. Wash the mixture and repeat 2–3 times until the pH of the final mixture solution stabilizes at 7. Finally, after freeze-drying, TEMPO oxidized cellulose was prepared. Preparation of Conductive Gel Inks. (1) Prepare 2wt% chitosan (CS) solution, and add 0.6ml of glacial acetic acid to 59.4ml of deionized water to obtain 60ml of 1% acetic acid solution. Take 58.8ml of it, add 1.2g of chitosan powder, and stir evenly on a digital magnetic stirrer until completely dissolved. (2) Add 0.1g of TEMPO-oxidized cellulose, 0.04g of multi-walled carbon nanotubes and 18ml of deionized water to the beaker, ultrasonically disperse for 15min to obtain a uniformly dispersed solution, then add 2g of PVA, heat it in a water bath, first heat it at 35 °C for 30 min, and then heat it at 95 °C for 150 min. Then add CS solution to the reaction solution, put it back into the water bath for heating and stirring for 2 min, put it into a vacuum drying oven to eliminate air bubbles, and finally obtain conductive gel ink. Preparation of Hydrogel Conductive Thin Film Sensors. (1) Write-through printing. Set the pattern-related parameters on the dispenser, and use the prepared hydrogel ink to print directly on the PET film at a pressure of 15.6 psi and a needle of 0.6mm. Each hydrogel conductive film is immediately placed in the -20 °C refrigerator for refrigeration, and the freeze-thaw cycle is performed after all the hydrogel film is printed. (2) Freeze-thaw cycle. The printed hydrogel conductive film is placed in the refrigerator and refrigerated at -20 °C for 20 h and allowed to stand at room temperature for 4 h, to perform three cycles. Finally, a cellulose-based hydrogel thin film sensor is obtained, as shown in the Fig. 1.

2.3 Testing and Characterization Fourier Infrared (FTIR) Spectroscopy Test. An appropriate amount of TEMPOoxidized cellulose was taken to determine its functional groups using Fourier infrared spectroscopy (NICOLET6700, Thermo Fisher Scientific, USA) in the range of 400– 4000 cm−1 , with 20 scans and 4 cm−1 .

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Fig. 1. Cellulose-based hydrogel thin film sensor

Performance Testing of Hydrogel Sensors. A digital source meter (2400, Keithley) is used to detect the relevant performance of the hydrogel sensor. To test the change of the relative resistance of the stretchable hydrogel sensor with strain, the flexible sensor is fixed on a conductive film tester to perform a tensile cycle of the sensor, and the sensitivity of the flexible stress sensor is calculated as shown in Eq. (1). GF =

R R − R0 = εR0 εR0

(1)

In the formula, ε is the strain that occurs when the sensor is stressed, and R, and R0 are the initial resistance and the changed resistance of the sensor. Application Performance Testing of Hydrogel Sensors. The application of hydrogel film sensor in the human movement was tested, and the flexible stress variable sensor of conductive hydrogel film was fixed on the tester’s knuckles, wrist joints, and elbow joints for bending and straightening tests to test its real-time resistance response to relevant human movements.

3 Results and Discussion Infrared Spectroscopy of TEMPO-Oxidized Cellulose. From Fig. 1, it can be observed that there are strong and broad absorption peaks at 3320–3360 cm−1 , which are the expansion and contraction vibration peaks of -OH in cellulose molecule, and the expansion and contraction vibration peaks of alkane C-H skeleton at 2891–2927 cm−1 , and the characteristic expansion and contraction vibration peaks of C = O in COOH in TEMPO-oxidised cellulose at 1680 cm−1 are sharp, indicating that a large number of carboxyl groups have been introduced in the oxidized cellulose molecule, and cellulose has been successfully modified into TEMPO-oxidized cellulose. Tempo-oxidized cellulose showed a sharp C = O peak in -COOH at 1680 cm−1 , indicating that a large number of carboxyl groups were introduced into the oxidized cellulose macromolecule, and the cellulose has been successfully modified into TEMPO-oxidised cellulose. Tensile Performance Test of Hydrogel Sensors. The hydrogel film sensor was fixed on the conductive film tester for testing, and the test results are shown in Fig. 2. In the tensile state of 100%, 200%, 300%, 400%, and 500%, the relative resistance change of the hydrogel film sensor increased with the increase of the degree of stretching, which was 0.1824, 0.3915, 0.5423, 0.7132 and 1.3154, respectively. At 100% tensile strain, the

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hydrogel thin film sensor is calculated by Eq. (1), The sensitivity of this sensor is 1.12 and the response time is 180ms at 100% tensile strain.

Fig. 2. (a) Infrared spectroscopy of TEMPO-oxidized cellulose (b) Tensile performance of hydrogel sensors at 100%-500%.

Hydrogel Sensor Application Performance Testing. The hydrogel sensor was fixed sequentially at the knuckles, wrist joints, and elbow joints, and connected to a digital source meter (2400, Keithley) to test its application performance in human motion detection. The straightening-bending motion of the knuckles was tested and the results are shown in Fig. 3 (a). When the finger is slowly bent, the hydrogel sensor then stretches and deforms, and the relative resistance also changes, when the finger is bent to the maximum, the deformation of the hydrogel sensor also reaches the maximum, the relative resistance changes to the peak, and as the finger goes from the maximum bent state to the slowly straightened state, the relative resistance also decreases. As the speed of finger bending increases, and the bending force increases, the peak value of the relative resistance change increases. In this way, the hydrogel sensor can detect the relevant movements of the knuckles of the human body, such as grasping objects, clenching fists, etc.

Fig. 3. (a)Test results of sensor application in finger joints. (b)Test results of sensor application in the wrist joint. (c)Test results of sensor application in elbow joint

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Human activity of the wrist joint was tested and the results are shown in Fig. 3(b). It is clear that the relative resistance change changes as the wrist flexion motion proceeds. In this way, we can use hydrogel sensors to detect the body’s wrist movements, such as shooting, feathering, etc. Human activity of the elbow joint is tested, and the test results are shown in Fig. 3(c). The hydrogel sensor responds to the bending motion of the elbow area in a clear way. This allows the hydrogel sensor to detect human elbow movements. For example, fitness strength training tests the elbow to measure fitness effectiveness.

4 Conclusions In summary, we successfully prepared a conductive hydrogel ink by the one-pot method, and a flexible hydrogel sensor with high flexibility, high conductivity, and high sensitivity was prepared by direct writing printing and freezing cycle. TEMPO oxidation cellulose was prepared by the TEMPO oxidation method, and CNT was added at the same time to improve the mechanical and electrical properties of the hydrogel. The preparation of hydrogel sensors by direct writing printing technology has great flexibility, controllability, and speed. The hydrogel sensor can stretch up to 500%, with a response time of 180ms and a sensitivity of 1.12 at 100% stretch. It can make very accurate identification of the activity law of the human elbow, wrist, and knuckles, and can monitor the large and small movements of the human body for a long time and stably, which is of great significance for the subsequent preparation and application of cellulose hydrogel sensors. Acknowledgment. This research is supported by the Shandong Province Science and Technology Small and Medium-sized Enterprise Innovation Capability Improvement Project (NO. 2021TSGC1168) and development of intelligent quality control system for high-end printing and processing (NO.2022TSGC2446).

References 1. Zhu, E., Xu, H., Xie, Y., et al.: Antifreezing ionotropic skin based on flexible, transparent, and tunable ionic conductive nanocellulose hydrogels. Cellulose 28(9), 5657–5668 (2021) 2. Zhang, Z., Chen, Z., Wang, Y., et al.: Bioinspired conductive cellulose liquid-crystal hydrogels as multifunctional electrical skins. Proc. Natl. Acad. Sci. 117(31), 18310–18316 (2020) 3. Zhou, J., Wang, H., Du, C., et al.: Cellulose for sustainable triboelectric nanogenerators. Adv. Energy Sustain. Res. 3(5), 2100161 (2022) 4. Zhang, W., Chen, X., Zhao, J., et al.: Cellulose template-based triboelectric nanogenerators for self-powered sensing at high humidity. Nano Energy 108, 108196 (2023) 5. Wang, H., Biswas, S.K., Zhu, S., et al.: Self-healable electro-conductive hydrogels based on core-shell structured nanocellulose/carbon nanotubes hybrids for use as flexible supercapacitors. Nanomaterials 10(1), 112 (2020) 6. Du, H., Zhang, M., Liu, K., et al.: Conductive PEDOT: PSS/cellulose nanofibril paper electrodes for flexible supercapacitors with superior areal capacitance and cycling stability. Chem. Eng. J. 428, 131994 (2022)

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7. Deng, P., Chen, F., Zhang, H., et al.: Conductive, self-healing, adhesive, and antibacterial hydrogels based on lignin/cellulose for rapid MRSA-infected wound repairing. ACS Appl. Mater. Interfaces 13(44), 52333–52345 (2021) 8. Zheng, C., Lu, K., Lu, Y., et al.: A stretchable, self-healing conductive hydrogels based on nanocellulose supported graphene towards wearable monitoring of human motion. Carbohyd. Polym.. Polym. 250, 116905 (2020) 9. Wang, H., Li, J., Yu, X., et al.: Cellulose nanocrystalline hydrogel based on a choline chloride deep eutectic solvent as a wearable strain sensor for human motion. Carbohyd. Polym.. Polym. 255, 117443 (2021) 10. Wu, P., Cheng, S., Yao, M., et al.: A low-cost, self-standing NiCo 2 O 4 @CNT/CNT multilayer electrode for flexible asymmetric solid-state supercapacitors. Adv. Func. Mater.Func. Mater. 27(34), 1702160 (2017) 11. Xu, X., Chen, Y., He, P., et al.: Wearable CNT/Ti3C2Tx MXene/PDMS composite strain sensor with enhanced stability for real-time human healthcare monitoring. Nano Res. 14(8), 2875–2883 (2021) 12. Ying, Z., Wang, Q., Xie, J., et al.: Novel electrically-conductive electro-responsive hydrogels for smart actuators with a carbon-nanotube-enriched three-dimensional conductive network and a physical-phase-type three-dimensional interpenetrating network. J. Mater. Chem. C 8(12), 4192–4205 (2020) 13. Wei, Y., Qian, Y., Zhu, P., et al.: Nanocellulose-templated carbon nanotube enhanced conductive organohydrogel for highly-sensitive strain and temperature sensors. Cellulose 29(7), 3829–3844 (2022) 14. Deng, Z., Hu, T., Lei, Q., et al.: Stimuli-responsive conductive nanocomposite hydrogels with high stretchability, self-healing, adhesiveness, and 3D printability for human motion sensing. ACS Appl. Mater. Interfaces 11(7), 6796–6808 (2019)

Properties of Charge Transfer Complex Based on Triphenylene Molecule Fuzhou Wang, Chunxiu Zhang, Ao Zhang, Xiaoli Song, Yonggang Yang, Yuguang Feng, Yi Fang, Yaohong Liu, and Ruijuan Liao(B) School of Printing and Packaging Engineering, Beijing Institute of Graphic Communication, Beijing, China [email protected]

Abstract. In this paper, 2,3-diethylester-6,7,10,11-tetrapentaloxy-triphenylene (23TPE) as electron donor and 2,4,7-trinitro-9-fluorenone (TNF) as electron acceptor were designed and synthesized, and their molecular structures were confirmed by infrared spectroscopy (FT-IR) and nuclear magnetic hydrogen spectroscopy (1 H-NMR). Product 23TPE/TNF was obtained by evenly mixing 23TPE and TNF at molar ratio 1:1. Infrared spectroscopy (FT-IR) and ultraviolet visible spectroscopy (UV-vis) were used to study its spectral characteristics. Polarizing microscope (POM) and differential scanning calorimeter (DSC) were used to investigate the liquid crystal properties. The experimental results showed that 23TPE/TNF doping formed a charge transfer complex (CTC). Keywords: Triphenylene · Electron donor · Electron acceptor · Charge transfer complex

1 Introduction The discotic liquid crystalline charge transfer complex is composed of an electron-rich discotic liquid crystal molecule as electron donor self-assembling through intermolecular force with another an electron-deficient molecule as electron acceptor [1, 2]. Its potential excellent photoelectric properties have attracted extensive attention from researchers. Triphenylene molecule has great liquid crystal properties, high carrier mobility in one dimension direction, as well as rich in electrons [3, 4]. Besides it can be used to form charge transfer complex with non-discogenic electron-deficient molecule 2,4,7-trinitro9-fluorenone [5, 6]. In this work, we designed and synthesized 2,3-diethylester-6,7,10,11-tetrapentaloxytriphenylene (23TPE) and 2,4,7-trinitro-9-fluorenone (TNF) molecules, which were uniformly mixed at molar ratio 1:1 to prepare charge transfer complex.

2 Experimental 2.1 Synthesis of 2,3-Diethylester-6,7,10,11-Tetrapentaloxy-Triphenylene If not specified, the chemicals are analytical reagents which are used in synthesis (Beijing Chemical Reagent Company) (Fig. 1). © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 359–364, 2024. https://doi.org/10.1007/978-981-99-9955-2_46

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Fig. 1. Synthesis pathway of 2,3-diethylester-6,7,10,11-tetrapentaloxy-triphenylene

Firstly, catechol undergoes a series of Williamson etherification reaction、Iodide reaction、coupling reaction、Scholl reaction and selective de-methoxy reaction to obtain 2, 3-dihydroxy-6, 7, 10, 11-tetrapentaloxy-triphenylene. And then 2, 3-dihydroxy6, 7, 10, 11-tetrapentaloxy-triphenylene was esterified with acetyl chloride to produce the 2,3-diethylester-6,7,10,11-tetrapentaloxy-triphenylene(23TPE). 2.2 Synthesis of 2,4,7-Trinitro-9-Fluorenone The deionized water and 9-fluorenone were added to the three-mouth flask, stirred and heated to 80°C, then the mixture of concentrated sulfuric acid and fuming nitric acid was added drop by drop, and the heating was stopped after 3 h of reaction. The yellow solid can be obtained by washing, drying and recrystallization (Fig. 2).

Fig. 2. Molecular structure of 2,4,7-trinitro-9-fluorenone

2.3 Synthesis of Charge Transfer Complex The CHCl3 hot solution of 2, 3-diethylester-6,7,10,11-tetramentylbenzophene was mixed with the CHCl3 hot solution of 2,4,7-tritro-9-fluorenone at the molar ratio of 1:1. The color of the solution turned to brown red. The solvent volatilized after standing for a period of time, and the brown-red precipitation was precipitated (Fig. 3).

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Fig. 3. Molecular structure of CTC23TPE-TNF (dotted lines represent charge transfer interaction forces)

3 Results and Discussion 3.1 FT-IR of CTC23TPE-TNF The infrared absorption spectra and main functional group wavenumbers of 23TPE 、TNF and doped charge-transfer complex are shown in Fig. 4 and Table 1, 2 and 3. It can be seen from Table 1 that the C = O vibration of the ester group appears at 1756cm−1 in the infrared absorption spectrum of 23TPE, but at 1766cm−1 in CTC23TPE-TNF . The symmetric and asymmetric stretching vibrations of NO2 were located at 1526cm−1 and 1342cm−1 in the infrared absorption spectra of TNF molecules, while those of CTC23TPE-TNF were located at 1537cm−1 and 1339cm−1 respectively. C-O-C stretching vibrations of ester and alkoxy chains can be observed at 1200cm−1 and 1129cm−1 of 23TPE molecule, but at 1230cm−1 and 1135cm−1 of charge transfer complex CTC23TPE-TNF respectively. The change of the infrared absorption peak of the group preliminarily indicates the formation of CTC.

Fig. 4. The infrared absorption spectra of CTC23TPE-TNF

3.2 UV Spectrum of CTC23TPE-TNF The ultraviolet absorption spectra of 23TPE and TNF molecules and the doped product CTC23TPE-TNF are shown in Fig. 5. As shown in Fig. 5, the doped product CTC23TPE-TNF presents a new absorption band at 370-408nm, which is the characteristic absorption of charge-transfer complex, further indicating that 23TPE and TNF molecules are doped to form a charge-transfer complex.

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l bond Sample

Chemica Frequency (cm−1 ) C=O

NO2

NO2

1732

1526

1342

CTC23TPE-TNF

1766

1537

1339

23TPE

1756

TNF

C-O-C

C-O-C

1230

1135

1200

1129

Fig. 5. Ultraviolet absorption spectra of CTC23TPE-TNF

3.3 Liquid Crystal Properties of CTC23TPE-TNF CTC23TPE-TNF was heated at 10°C/min under a polarizing microscope with a hot table. When the sample melts at 190°C, the field of view is completely clear, the sample enters the isotropic liquid state, and no liquid crystal texture appears during the whole heating process. Then the sample is cooled from the isotropic liquid temperature at a rate of 10°C/min. When the temperature drops to 175°C, the angular cone texture shown in Fig. 6 (b) can be observed, which is a classic hexagonal columnar phase texture. Figure 6 (a) shows the cone texture observed at temperature drop to 50 °C, which can be maintained to room temperature. According to the DSC curves of 23TPE, TNF and doped CTC23TPE-TNF in Fig. 5, it can be seen that the endothermic peak temperature and exothermic peak temperature of doped CTC23TPE-TNF change significantly compared with that of 23TPE and TNF in both heating and cooling processes, more indicating the formation of charge-transfer complex. The compound was confirmed to be the target product by1H-NMR. 23TPE:1H NMR (400 MHz, Chloroform-d) δ 8.22 (s, 2H), 7.80 (s, 4H), 4.23 (s, 8H), 2.40 (s, 6H), 1.96 (p, J = 6.5 Hz, 8H), 1.48 (d, J = 7.8 Hz, 16H), 0.97 (td, J = 7.2, 1.1 Hz, 12H). TNF:1H NMR (400 MHz, Chloroform-d) δ 9.04 (d, J = 2.1Hz,1H), 8.83 (d, J = 2.1 Hz, 1H), 8.69 (d, J = 2.3 Hz, 1H), 8.60 – 8.57 (m, 1H), 8.38 (d, J = 8.5 Hz, 1H).

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Fig. 6. Polarized image and DSC curve of CTC23TPE-TNF

Fig. 7. Nuclear magnetic hydrogen spectrum of CTC23TPE-TNF

CTC23TPE-TNF :1H NMR (400 MHz, Chloroform-d) δ 8.96 (d, J = 2.5 Hz, 1H), 8.71 (s, 1H), 8.57 (s, 1H), 8.51 (s, 1H), 8.26 (s, 1H), 8.15 (s, 2H), 7.74 (s, 4H), 4.21 (dt, J = 13.4, 6.3 Hz, 8H), 2.40 (s, 6H), 1.96 (p, J = 6.9 Hz, 8H), 1.57 – 1.44 (m, 16H), 0.98 (t, J = 7.2 Hz, 12H). It can be seen from the nuclear magnetic hydrogen spectrum in Fig. 7 that the chemical shifts of protons on the aromatic ring, alkyl chain and ester group all changed greatly before and after doping, more precisely indicating the formation of charge transfer complex.

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4 Conclusion The development of new materials with excellent properties has always been a research direction in the field of science. When 23TPE and TNF were doped with molar ratio 1:1, a new absorption band appeared in the ultraviolet absorption spectrum of the product CTC at 370-408nm.The wavenumbers of the main functional groups such as NO2 (TNF), CO-C(23TPE) and C = O(23TPE) in the infrared absorption spectrum of CTC all shifted to a large extent. The exothermic peak and endothermic peak of DCS curve changed obviously. The protons on aromatic ring, alkyl chain and ester group also have a large chemical shift in the NMR hydrogen spectrum. The formation of charge transfer complex was confirmed. Organic charge transfer complexes have a bright application prospect in the fields of photovoltaic, nonlinear optics, bipolar carrier transport and pharmaceuticals, which provides a new research idea for the design and preparation of new organic solid materials [1, 5]. Acknowledgments. This work is supported by the Beijing Natural Science Foundation (2222055), Discipline construction of material science and engineering (21090123007), The Ministry of Education Key Laboratory of Luminescence and Optical Information, Open project (NO.KLLI0BJTUKF2204), BIGC project (NO.Ee202203), (NO.Ec202206),(NO.Eb202201).

References 1. Bullock, J.E., Carmieli, R., Mickley, S.M., Vura-Weis, J., Wasielewski, M.R.: Photoinitiated charge transport through π-stacked electron conduits in supramolecular ordered assemblies of donor− acceptor triads. J. Am. Chem. Soc. 131, 11919–11929 (2009) 2. Kumar, S.: Recent developments in the chemistry of triphenylene-based discotic liquid crystals. Liq. Cryst.Cryst. 31, 1037–1059 (2004) 3. Otmakhova, O., et al.: New complexes of liquid crystal discotic triphenylenes: induction of the double gyroid phase. Phys. Chem. Chem. Phys. 23, 16827–16836 (2021) 4. Haverkate, L.A., et al.: On the morphology of a discotic liquid crystalline charge transfer complex. J. Phys. Chem. B 116, 13098–13105 (2012) 5. Goetz, K.P., Vermeulen, D., Payne, M.E., Kloc, C., McNeil, L.E., Jurchescu, O.D.: Chargetransfer complexes: new perspectives on an old class of compounds. J. Mater. Chem. C 2, 3065–3076 (2014) 6. Pal, S.K., Setia, S., Avinash, B., Kumar, S.: Triphenylene-based discotic liquid crystals: recent advances. Liq. Cryst.Cryst. 40, 1769–1816 (2013)

Preparation and Performance Test of Electrophoretic Particles Modified by Nano TiO2 Jingjing Guo, Chunxiu Zhang, Ruijuan Liao, Yi Fang, Yuguang Feng, Xiaoli Song, Ao Zhang, and Yonggang Yang(B) School of Printing and Packaging Engineering, Beijing Institute of Graphic Communication, Beijing 102600, China [email protected]

Abstract. In this paper, nano TiO2 was modified to achieve better dispersion effect and improve the surface charge of nano TiO2 , so as to prepare white electrophoretic particles with excellent performance. The surface of nano TiO2 was modified by silane coupling agent, polymer surfactant and polymer coating. The modification of polymer coating was the main modification, and the modification was assisted by silane coupling agent KH-570 and polymer surfactant polyethylpyrrolidone (PVP). TiO2 /p(St-DVB-AM) particles with titanium dioxide as core and styrene, divinylbenzene and acrylamide crosslinked polymer as coating layer were prepared by one-pot precipitation polymerization. The experimental results show that TiO2 /p (St-DVB-4-AM) particles prepared with 0.4 g AM have the best performance, and the particle size is about 500 nm. Keywords: Nano TiO2 surface modification · Polymer coating · Surfactant

1 Introductions Titanium dioxide is widely used in pigments, coatings, photocatalysts and so on. It has stable chemical properties, a density of about 4 g cm−3 , and small absorption in the range of visible light. Therefore, titanium dioxide shows high whiteness and is a high-quality white pigment. At the same time, titanium dioxide has strong absorption in UV region and can be used as UV blocking material. Titanium dioxide particles are often used as photocatalyst support because of their stability and wide band gap [1, 2]. Titanium dioxide has abundant surface hydroxyl group, which can participate in the organic synthesis process, which is conducive to the surface modification. The surface superhydrophilicity of titanium dioxide is related to the surface hydroxyl group, and the number and structure of hydroxyl group formed in different water and oxygen environment will cause different surface properties. Nano TiO2 particles as white electrophoretic particles have the advantages of high chemical stability and good optical properties, but its affinity with organic matter is low, nano TiO2 as electrophoretic material is difficult to disperse evenly in organic solvents, affecting the device performance [3–6]. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 365–369, 2024. https://doi.org/10.1007/978-981-99-9955-2_47

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2 Experiment 2.1 TiO2 Surface Was Modified by KH-570 The methoxy group of KH-570 is hydrolyzed into hydroxyl group, which then condensates with the hydroxyl group on the surface of TiO2 or itself to remove a molecule of water, thus combining with the surface of TiO2 to achieve the effect of surface modification of titanium dioxide (Fig. 1).

Fig. 1. Experimental process of surface modification of TiO2 with KH-570

2.2 Prepare of TiO2 /p(St-DVB-AM) Particle Because the Q values of St, DVB and AM were relatively different, the e values of AM were significantly different from those of St and DVB, showing a tendency of alternating copolymerization. The monomer generates a polymer chain under the action of the initiator, and as the chain length increases beyond the solubility limit, it precipitates from the solution to the surface of TiO2 dispersed in the solution, thus forming a polymer coating. The Hoffmann degradation reaction removes the carbonyl group and produces a primary amine to form an ammonium salt in an alkaline solution (Fig. 2).

Fig. 2. Schematic diagram of polymer coating

Methanol was used as solvent, azodiisobutyronitrile as initiator, and St, DVB and AM were used as reaction monomers to obtain polymerization products. Then TiO2 was used as nuclear raw material. After the reaction, the products were added to the ball mill for ball grinding, and the products were dried in vacuum oven to complete the surface functionalization of titanium dioxide. Finally, TiO2 /p(St-DVB-AM) particles were treated with surface ionization and Hoffmann degradation.

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3 Results and Discussion 3.1 Infrared Spectrum of TiO2 /KH-570 Particles The unmodified titanium dioxide has hydroxyl absorption peak at about 3450 cm−1 , and the wide and large absorption peak at about 700 cm−1 is Ti-O bond absorption peak. Seen from infrared, silane coupling agent already exists on the surface of titanium dioxide. 2925 cm−1 and 2853 cm−1 are the C-H stretching vibration peaks of methyl group and methylene group in KH-570, and 1712 cm−1 are the C = O stretching vibration peaks of acyl group in KH-570. The C-H bending vibration of methyl group and methylene group in KH-570 was at 1400 cm−1 , and the stretching vibration peak of Si-O bond was at 1106 cm−1 (Fig. 3).

Fig. 3. Infrared spectrum of TiO2 /KH-570 particles

3.2 Infrared Spectra of TiO2 /p(St-DVB-AM) Particles As shown in Fig. 4, unmodified titanium dioxide has a hydroxyl absorption peak at about 3500 cm−1 , and a wide and large absorption peak at about 700 cm−1 is the TiO bond absorption peak. The sharp saturated C-H stretching vibration at 2922 cm−1 and 2854 cm−1 indicated that the polymerization of St, DVB and AM occurred. The absorption peak at 3087 cm−1 , 3063 cm−1 , 3029 cm−1 is C-H stretching vibration in unreacted vinyl. 1600 cm−1 , 1510 cm−1 , 1493 cm−1 , 1448 cm−1 was the respiratory vibration peak of benzene ring skeleton. At 1288 cm−1 is the stretching vibration peak of C-N bond; The N-H stretching vibration peak is located at 3390 cm−1 , and the characteristic absorption peak of C = O in amide is located at 1680 cm−1 (Fig. 4). 3.3 Surface Morphology Characterization of TiO2 /p(St-DVB-AM) Particles From (a) to (f) in Fig. 5, the amount of AM added varies from 0.2g, 0.4g, 0.6g, 0.8g,When 1.0g increased to 1.2g, the SEM images of TiO2 /p(St-DVB-AM) particles showed uneven particle size, with distribution of 100–600 nm. The particles in (b) and (e) show high dispersion, good sphericity, smooth surface, uneven size but small average particle size.

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Fig. 4. Infrared spectra of TiO2 /p(St-DVB-AM) particles

Fig. 5. Surface morphology characterization of TiO2 /p(St-DVB-AM) particles

4 Conclusion In this paper, nano TiO2 particles with better dispersibility were obtained by surface modification. The surface morphology of TiO2 /p(St-DVB-AM) particles prepared with AM as functional monomer reached the best state when the addition amount was 1.0 g, and the dispersion of nano TiO2 particles was the best, and the particle size was about 178 nm.PVP reduced the aggregation and accumulation of polymer-coated titanium dioxide particles, and the modification effect was obvious. Acknowledgments. This work is supported by the Beijing Natural Science Foundation (2222055), The Ministry of Education Key Laboratory of Luminescence and Optical Information, Open project (NO.KLLI0BJTUKF2204), BIGC project (NO.Ee202203),

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(NO.Ec202206),(NO.Eb202201), Discipline construction of material science and engineering(21090123007).

References 1. Fu, C., Wei, X.: Research progress on crystal transformation of titanium dioxide. Mater. Introduction (03), 37–38+47 (1999) 2. Thamaphat, K., Limsuwan, P., Ngotawornchai, B.J.A., et al.: Phase characterization of TiO2 powder by XRD and TEM. Agric. Nat. Resour. 42(5), 357–361 (2008) 3. Sabzi, M., Mirabedini, S.M., Zohuriaan-Mehr, J., et al.: Surface modification of TiO2 nanoparticles with silane coupling agent and investigation of its effect on the properties of polyurethane composite coating. Prog. Org. Coat. 65(2), 222–228 (2009) 4. Zhao, J., Milanova, M., Warmoeskerken, M.M.C.G., et al.: Surface modification of TiO2 nanoparticles with silane coupling agents. Colloids Surf. A 413, 273–279 (2012) 5. Wang, Q., Wang, C.: TiO2 for E ink_ a study on the surface modification and dispersion performance of coloring particles. Fine Chemicals 27(04), 338–341+412 (2010) 6. Lunardi, C.N., Gomes, A.J., Rocha, F.S., et al.: Experimental methods in chemical engineering: zeta potential. Can. J. Chem. Eng. 99(3), 627–639 (2021)

Preparation and Characterization of Liquid Crystal/Carbon Nanotube/Polyaniline Composites Xu Zhou1,2,3 and Fuqiang Chu1,2,3,4(B) 1 Faculty of Light Industry, Qilu University of Technology (Shandong Academy of Sciences),

Jinan 250353, China [email protected] 2 State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, China 3 Key Laboratory of Green Printing & Packaging Materials and Technology in Universities of Shandong, Faculty of Light Industry, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, China 4 Kiev College, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, China

Abstract. Nowadays, the doping of liquid crystal (LC) materials with nanomaterials shows extraordinary potential to improve the electro-optical properties of liquid crystals. Among them, complexes of carbon nanotubes (CNTs) and polyaniline (PANI) doped in liquid crystals can fully utilize the synergistic effect of CNTs and PANI. In this paper, the capping of carbon nanotubes by polyaniline was realized by polymerization of aniline on the surface of multi-walled carbon nanotubes (MWCNT). Liquid crystal physical gels were prepared in liquid crystal 4-n-pentyl4’-cyanobiphenyl (5CB) by using poly(vinyl alcohol) (PVA) as a gelation factor, and carbon nanotube/polyaniline composites were doped in the process. The above composite liquid crystal physicogels were coated twice to achieve a uniform orientation of the LC molecules. When the doping amount of CNT/PANI was 1 wt%, the resistance of the oriented composite film was approximately 46,500  lower compared with that of the liquid crystal hydrogel film. A new idea is provided for the application of liquid crystals in electrode preparation. Keywords: Liquid crystal · Carbon nanotube · Polyaniline

1 Introduction Liquid crystals (LC) [1] are favored for their excellent mobility, unique birefringence properties, and are widely used in electro-optical devices [2] and sensors [3]. However, high resistivity is usually exhibited in liquid crystal materials. Therefore, for the application of liquid crystal materials in electrical applications, it is essential to improve their electrical conductivity. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 370–374, 2024. https://doi.org/10.1007/978-981-99-9955-2_48

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Liquid crystal doped nanoparticles have been a hot research topic in recent years. Carbon nanotubes (CNTs) have attracted great research interest due to their excellent electrical and mechanical properties [4, 5]. The combination of carbon nanotubes and liquid crystal molecules can improve the electrical conductivity of LC/CNT materials, and through the polymerization of aniline [6, 7] on the surface of carbon nanotubes and then the surface coating of carbon nanotubes by polyaniline, the LC/CNT/PANI materials can achieve lower electrical resistance. In recent years, a method based on liquid crystals physical gels [8] has been proposed to reduce the mobility of liquid crystal molecules and enhance mechanical stability, which has important applications in the fields of photonics [9] and flexible electronic devices [10]. In this work, liquid crystal physical gels were made using liquid crystal 5CB doped with CNT/PANI composite system using poly(vinyl alcohol) (PVA) as the gelation factor, and finally the ordering degree of the liquid crystals was improved by the coating method. Compared with conventional liquid crystal materials, the prepared LC/CNT/PANI composite system can effectively reduce the resistance.

2 Experimental 2.1 Experimental Materials and Fabrication Preparation of Liquid Crystal Physical Gel. Measure 7.5 mL of liquid crystal 5CB (99.8%, Nanjing Sanjiang New Materials R&D Co.) into 30 mL of deionized water, stir and disperse. Weigh 5g of polyvinyl alcohol (analytical pure AR, Songsen New Materials Technology Co.) was added to the above dispersion. It was placed in a water bath and kept at 35 °C for 0.5 h, then 95 °C for 4 h. Liquid crystal physical gel was obtained after cooling for 12 h. The liquid crystal physical gel doped with 1 wt% CNT/PANI was prepared by adding CNT/PANI dispersion. LC Orientation and Preparation of LC/CNT/PANI Films. 100 μL of liquid crystal physical gel was uniformly coated on one side of the PET film. First, the first coating was applied using a 9 μm coating bar at a speed of 5 mm/s and a pressure of 2.156 N, and cooled at 22 °C for 72 s. A second coating was then applied with a 0 μm applicator rod at a speed of 4 mm/s and a pressure of 7.056 N. The coating was kept at a low temperature of −20 °C for 20 h and at room temperature of 25 °C for 4 h. Major Equipment. In this study, modified films were analyzed by Electrochemical Workstation (PGSTAT302N, Swiss Aptus China Ltd.); Polarizing Microscope (LV100NPOL, Nikon Imaging Instruments Sales Ltd.); Scanning Electron Microscopy (Regulus8220, HITACH Japan).

2.2 Testing and Characterization Scanning Electron Microscopy (SEM) Testing. SEM presents a magnified image of a sample, and it is an important tool for characterizing the microscopic morphology of a sample.

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Polarized Light Microscopy (POM) Testing. POM is an important tool for the analysis of liquid crystal orientation using the polarizing properties of light. Electrochemical Performance Testing. Using an electrochemical workstation, impedance testing is performed on the prepared conductive films.

3 Results and Discussion 3.1 CNT/PANI Performance Analysis SEM Analysis. As shown in Fig. 1(a), the untreated CNT surface is smooth and no PANI is attached. However, Fig. 1(b) shows a rougher CNT surface, indicating that aniline polymerized on the surface of carbon nanotubes and successfully achieved polyaniline wrapping around carbon nanotubes.

Fig. 1. SEM images of (a) CNT material and (b) CNT/PANI material with a CNT mass ratio of 35 wt% at 50,000×magnification

3.2 Liquid Crystal Orientation Analysis POM Analysis. As shown in Fig. 2(e), the POM plots show that the liquid crystal physical gel appear as microdroplets after the second coating, and Fig. 2(a), (b) and (c) show that the liquid crystal microdroplets exhibit the birefringent nature of liquid crystals. However, with the insertion of the λ-wavelength compensator (550 nm delay), the PET substrate appears purple and when its slow axis is +45° to the analyzer the liquid crystal microdroplets appear blue, indicating that the total birefringence increases when the microdroplets are parallel to the slow axis of the λ-wave sheet, while they appear red when the droplets are perpendicular to each other, and this color difference indicates that the liquid crystal orientation direction is parallel to the second coating direction.

3.3 LC/CNT/PANI Materials Impedance Analysis As can be seen from Fig. 3, the impedance curve of the uncoated oriented LC hydrogel material with the intersection of the real part axis is about 71000 , and after adding CNT the liquid crystal hydrogel material shows a significant decrease in resistance, and

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Fig. 2. Under 1000x conditions (a) POM image of LC microdroplets in the LC/CNT/PANI composite system after the second coating taken using a cross-polarizer, with the distance of the streak from the polarizer at +45°, (b) 0°, (c) −45°, (d) POM image with the cross-polarizer at −45° with the insertion of the λ-wavelength compensator (550 nm delayed), (e) optical image, and (f) POM image with the insertion of the λ-wavelength compensator (550 nm delayed) and with the cross-polarizer at −45° with the direction of the arrows indicating the direction of the coating.

after adding CNT covered by PANI the resistance of the liquid crystal hydrogel material decreases again, and the impedance curve of the coated oriented LC/CNT/PANI with the intersection of the real part axis is about 24500 . Therefore, the resistance of the LC/CNT/PANI composite after orientation is reduced by about 46500  compared to the uncoated LC hydrogel material. Therefore, the resistance of the oriented LC/CNT/PANI composite is reduced by about 46500  compared to the unoriented LC hydrogel material.

Fig. 3. Impedance test image of LC hydrogel material

4 Conclusions In conclusion, in this paper, liquid crystal physical gels were made using nematic phase liquid crystals 5CB with poly (vinyl alcohol) as the gelation factor, and CNT/PANI materials were doped in the liquid crystals. The resistance of the liquid crystal physical gel was reduced because the carbon nanotubes were wrapped by polyaniline, which

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improved the dispersion of the carbon nanotubes in the liquid crystal. Finally, the liquid crystal orientation was successfully achieved by coating, which improved the ordering of the liquid crystals and carbon nanotubes, and facilitated the electron transport in the system, and further reduced the resistance of the material. The resistance of the oriented PVA/LC/CNT/PANI composite was reduced by about 46,500  compared with that of the PVA/LC composite material. It provides a new idea for the application of liquid crystals in the preparation of electrodes. Acknowledgement. This research is supported by Shandong Province Science and Technology Small and Medium-sized Enterprise Innovation Capability Improvement Project (NO. 2021TSGC1168) and development of intelligent quality control system for high-end printing and processing (NO. 2022TSGC2446).

References 1. Yang, F.Z.: From crystal optics to liquid crystal optics — the development of optical techniques for studying liquid crystal physics. Chin. J. Liq. Cryst. Displays 31(1), 1–39 (2016). https:// doi.org/10.3788/YJYXS20163101.0001b 2. Tikhonov, E.A., Ilchishin, I.P.: Resonanse nonlinear optical properties of dye-doped liquid crystals under pulse excitation: insight into early experiments. J. Mol. Liq. 267, 73–80 (2018). https://doi.org/10.1016/j.molliq.2018.02.070 3. Lai, Y.-T., Kuo, J.-C., Yang, Y.-J.: A novel gas sensor using polymer-dispersed liquid crystal doped with carbon nanotubes. Sens. Actuators A 215, 83–88 (2014). https://doi.org/10.1016/ j.sna.2013.12.021 4. Khan, I., Saeed, K.: Nanoparticles: properties, applications and toxicities. Arab. J. Chem. 12(7), 908–931 (2019) 5. Jeevanandam, J., Barhoum, A., Chan, Y.S., et al.: Review on nanoparticles and nanostructured materials: history, sources, toxicity and regulations. Beilstein J. Nanotechnol. 9(1), 1050–1074 (2018) 6. Bhadra, S., Khastgir, D., Singha, N., et al.: Progress in preparation, processing and applications of polyaniline. Prog. Polym. Sci. 34(8), 783–810 (2009) 7. Shayeh, J., Norouzi, P., Ganjali, M.: Effect of thickness on the capacitive behavior and stability of ultrathin polyaniline for high speed super capacitors. Russ. J. Electrochem. 52(10), 933–937 (2016) 8. Wang, H., Zhang, H.: The preparation and properties of circularly polarized luminescent liquid crystal physical gels with self-supporting performance. Soft Matter 29(07), 5331–5526 (2022) 9. Tong, X., Zhao, Y., An, B.K., et al.: Fluorescent liquid-crystal gels with electrically switchable photoluminescence. Adv. Func. Mater. 16(14), 1799–1804 (2006) 10. Lin, Y.-H., Yang, C.-M.: A polarizer-free flexible display using dye-doped liquid-crystal gels. J. SID 17(10), 821–826 (2009)

Study on Synthesis of a Novel Luminescent Liquid Crystal and Its Luminescent Properties and Liquid Crystal Performance Shiyi Qiao, Chunxiu Zhang, Ruijuan Liao, Yuguang Feng, Xiaoli Song, Yonggang Yang, Ao Zhang, Li An, and Yi Fang(B) School of Printing and Packaging Engineering, Beijing Institute of Graphic Communication, Beijing 102600, China [email protected]

Abstract. In this paper, a novel light-emitting liquid crystal molecule was designed and synthesized using benzophenanthrene and tetraphenylene as the base unit by linking flexible alkoxy chains. The structures of the synthesized molecules were confirmed by nuclear magnetic hydrogen spectroscopy (1HNMR), infrared spectroscopy (FT-IR) and ultraviolet spectroscopy (UV-VIS). The liquid crystal properties and phase structures of the synthesized target molecules and doped systems were characterized by differential scanning calorimetry (DSC) and polarized light microscopy (POM). The aggregation-induced luminescence properties were judged by observing the luminescence intensity under UV lamp by being in different ratios of tetrahydrofuran-water solvents. Useful information is provided for organic optoelectronic applications. Keywords: Discotic Liquid Crystal · Benzophenanthrene · AIE · Tetraphenylene

1 Introduction Luminescent liquid crystal molecules not only have the order and stability of liquid crystals, but also have luminescent properties, which have a very broad application prospect [1]. Ye et al. constructed a novel luminescent liquid crystal molecule by introducing a cholesterol molecule into a tetrastyrene moiety via a flexible alkyl chain, and DSC and POM showed that this AIE molecule has the typical focal cone weave of cholesteric phase liquid crystals. This AIE molecule exhibited CPL with a high dissymmetry factor (~10 − 2) and high fluorescence efficiency (42%) in the solid state [2]. Benzophenanthrene is a typical disk-mounted liquid crystal molecule with good liquid crystal properties and optoelectronic properties. Tetraphenylene is a typical AIE molecule with aggregation-induced luminescence properties. In this work, we designed and synthesized a benzophenanthrene and tetraphenylene molecule linked by flexible alkyl chains [3].

© The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 375–379, 2024. https://doi.org/10.1007/978-981-99-9955-2_49

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2 Experimental 2.1 Synthesis of H4T4 (Compound 9) If not specified, the chemicals used in the synthesis were all analytical reagents (Beijing Chemical Reagent Company) (Fig. 1).

Fig. 1. Synthesis pathway of H4T4 (compound 9)

The reaction of catechol (compound 1) with 1-bromobutane to form 1,2dibutoxybenzene (compound 2) by Williamson etherification reaction, the ring incorporation by Schorr reaction catalyzed by ferric chloride to obtain (hexabutoxybenzophenanthrene) HAT4 (compound 3), the reduction by catechol borane to obtain monohydroxybenzophenanthrene (HAT4-OH) (compound 4), the etherification reaction to HAT4 (compound 4) was reacted with 1,4-dibromobutane to produce compound 5 [4]. In the system of zinc powder, titanium tetrachloride and pyridine, benzophenone (compound 6) and 4-hydroxybenzophenone (compound 7) were coupled by McMurry reaction to form 4-hydroxytetraphenylene (compound 8).Compound 5 and compound 8 were combined by Williamson etherification reaction to produce the final target product H4T4 (compound 9) [5].

3 Results and Discussion 3.1 FT-IR and 1HNMR of H4T4 The compound was confirmed to be the target product by FT-IR and 1 H-NMR. FT-IR (KBr): vmax/cm−1 3100 (C-H), 2970 (C-H), 2800(C-H),1600 (C = C), 1260 (C-O-C); 1 HNMR(300 MHz, CDCl3 ): 7.84 (s, 6H, Ar-H), 7.20–6.98 (m, 14H, Ar-H), 6.95–6.87 (d, 3H, Ar-H), 6.72–6.65 (d, 2H, Ar-H), 4.24 (m, 12H, OCH2 ), 4.02 (t, 2H, OCH2 ), 2.00–1.94 (m, 10H, OCH2 CH2 ), 1.62–1.54 (m, 10H, OCH2 CH2 CH2 ), 1.04– 1.00 (m, 15H, CH3 ) (Fig. 1). The peak of the low field in the NMR hydrogen spectrum represents the hydrogen in the benzene ring of HAT4 and tetraphenyl; The middle peaks 4.24 and 4.02 represent the hydrogen on the carbon attached to the ether; The peak of the high field represents the hydrogen in the flexible carbon chain. The combination of the carbon-carbon double bond represented by peak 1600 in the infrared map and the ether represented by peak 1260 can prove that the target compound H4T4 is synthesized.

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Fig. 2. FT-IR and 1 HNMR of H4T4

3.2 Liquid Crystal Properties of H4T4 The liquid crystal properties of the compound were studied by recording the phase transition data with a differential scanning thermal analysis (DSC) instrument and observing the weave pattern and recording the phase transition temperature with a polarized light microscope (POM) equipped with a heating stage. The DSC curve of H4T4 was obtained by scanning the sample at a rate of 10°C/min as shown in Fig. 3. A heat absorption peak appears during the temperature rise and fall. The heat absorption peaks appeared at 28.3°C and 25.2°C during the temperature rise and fall, indicating that only one phase structure change of H4T4 occurred during the temperature rise and fall, which can be presumed to be the temperature change during the melting of the sample.

Fig. 3. DSC curves of H4T4

H4T4 was placed under a polarizing light microscope (POM) and heated using a rate of 10°C/min. Figure 4 shows the images of H4T4 after going through the heated molten state and annealing. It can be observed that there is no obvious formation of liquid crystal weave, and combined with the DSC curve, it can be judged that H4T4 does not have liquid crystal properties [6].

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Fig. 4. POM image of H4T4

3.3 Analysis of the Luminescence Performance of H4T4 Different volume fractions of tetrahydrofuran and water solutions containing 4H4T were configured and tested for UV absorption spectra according to a volume gradient of 10% to 90%. As shown in the Fig. 5, the UV absorption intensity showed a decreasing trend with the increase of the volume fraction of the undesirable solvent water, which indicated that aggregation-induced burst occurred in H4T4, and therefore it was concluded that H4T4 had no aggregation-induced luminescence effect.

Fig. 5. Fluorescence Spectra of H4T4 in Different Volume Fractions of Tetrahydrofuran/Water Solutions

4 Conclusion From the synthesis and studies of the dimer H4T4, it can be judged that this molecule has neither the liquid crystal properties of benzophenanthrene nor the aggregation-induced luminescence (AIE) properties of tetraphenylene. It can be seen that not all liquid crystal molecules and AIE molecules can achieve the coexistence of liquid crystal and AIE properties through linking. I speculated that in the dimer H4T4, the ACQ effect of the disk-like liquid crystal molecule HAT4 was stronger than the AIE effect of tetraphene,

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so the dimer H4T4 showed ACQ; At the same time, the link of the short flexible chains brings the two molecules close together, which causes the rigidity to increase, destroying the liquid crystal properties. Acknowledgments. This work is supported by the Natural Science Foundation of China (No.21905028), Research Project of Beijing Municipal Commission of Education (No.KM202010015005), BIGC Project (Eb202105), Discipline construction of material science and engineering(21090123007),the Scientific Research Project of Beijing Educational Committee (KM202110015009).

References 1. Li, Z., Luo, Z., Wang, P., Zhenqiang, Y., Chen, E., Xie, H.: Luminescent liquid crystalline polymers: molecular fabrication, structure-properties and their applications. Prog. Chem. 34(4), 787–800 (2022) 2. Ye, Q., et al.: Thermally tunable circular dichroism and circularly polarized luminescence of tetraphenylethene with two cholesterol pendants. J. Mater. Chem. C 3, 6997–7003 (2015) 3. Collings, P.J., Hird, M., Huang, C.C.: Introduction to liquid crystals: chemistry and physics. Am. J. Phys. 66(6), 551–551 (1998). https://doi.org/10.1119/1.18901 4. Wang, H., Zhao, E., Jacky, W.Y.L., Tang, B.Z.: AIE luminogens: emission brightened by aggregation. Mater. Today 18, 365–377 (2015) 5. Duan, X.-F., Zeng, J., Lü, J.-W., Zhang, Z.-B.: Insights into the general and efficient cross McMurry reactions between Ketones. J. Org. Chem. 71(26), 9873–9876 (2006). https://doi. org/10.1021/jo061644d 6. Anja, R.A., et al.: Lyotropic liquid-crystalline behavior in disc-shaped compounds incorporating the 3,3 -di(acylamino)-2,2 -bipyridine unit. Adv. Mater. 10(11), 873–876 (1998)

Synthesis and Mesomorphism of a Novel Asymmetrical Triphenylene Derivatives Dimer Jinwei Wang1 , Chunxiu Zhang1 , Yuguang Feng1 , Ao Zhang2 , Xiaoli Song1 , Yi Fang1 , Yaohong Liu1 , and Ruijuan Liao1(B) 1 School of Printing and Packaging Engineering, Beijing Institute of Graphic Communication,

Beijing 102600, China [email protected] 2 School of Basic Education, Beijing Institute of Graphic Communication, Beijing 102600, China

Abstract. In this paper, the design and synthesis of an asymmetric triphenylene dimer molecule with alkoxy chain lengths of six and four carbons linked by flexible carbon chains with a length of twelve is reported. The characterization results obtained from 1H-NMR and FT-IR confirmed that the structure of the compound was as expected. DSC (Differential Scanning Calorimetry) and POM (Polarization Microscope) techniques revealed its liquid crystal and thermal properties, showing an ordered mesophase of the columnar phase. Keywords: Triphenylene · Discotic Liquid Crystal · Columnar Phase

1 Introduction Liquid crystal molecular dimers usually refer to a class of compounds in which two mesogens connected by flexible or rigid molecular chains exist in one molecule at the same time. As an ideal research model, liquid crystal dimer is of great significance to the study of the phase transition behavior of liquid crystals. The triphenylene dimer molecule was first reported in 1987 by H. Ringsdorf et al. A molecule that exhibits a lamellar phase was obtained by linking triphenylene molecules through rod-like mesogens [1]. Subsequent related studies have shown that the participation of an asymmetric structure enables the triphenylene dimer molecule to have better phase transition and liquid crystal properties, making it a potential application value for optoelectronic devices [2–7]. In this work, triphenylene molecules with alkoxy chain lengths of six and four carbons were designed and synthesized, and they were linked by flexible carbon chains with a length of twelve.

2 Experiment If not specified, the chemical reagents were analytical reagents which were used in synthesis (Beijing Chemical Reagent Co). © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 380–384, 2024. https://doi.org/10.1007/978-981-99-9955-2_50

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2.1 Synthesis of Product T6C12T4 The comprehensive synthetic route is depicted in detail in Fig. 1. All products were subjected to standardized purification processes unless explicitly stated otherwise. The structural characterization of the products obtained at each stage will be elaborated upon in the results and discussion section.

Fig. 1. Synthesis pathway of T6C12T4

Synthesis of 2-Hydroxy-3, 6, 7, 10, 11-Pentahexyloxy-Triphenylene. Firstly, catechol was used as raw material. Through the Williamson etherification reaction, brominated n-hexane was added under alkaline conditions to generate o-phenylenedihexyl ether. Subsequently, the product purified under reduced-pressure distillation and anhydrous ferric chloride underwent Scholl reaction in a solvent to generate 2, 3, 6, 7, 10, 11hexahexyloxytriphenylene (HAT6). Ultimately it was the selective elimination reaction of borane derivatives. Synthesis of 2-Hydroxy-3, 6, 7, 10, 11-Pentabutoxy-Triphenylene. The synthesis of 2-hydroxy-3, 6, 7, 10, 11-pentabutoxy-triphenylene was similar to 2-hydroxy-3, 6, 7, 10, 11-pentahexyloxy- triphenylene, only the equivalent of n-bromohexane in the original raw material was replaced by n-bromobutane. Synthesis of 2-(12-Bromododecyl)-3, 6, 7, 10, 11-Pentahexyloxy-Triphenylene. MHT6 and 1,12-dibromododecane were refluxed in a solution of potassium carbonate in acetone to carry out Williamson etherification and obtain 2-(12-bromododecyl)-3, 6, 7, 10, 11-pentahexyloxy-triphenylene. Synthesis of T6C12T4. MHT4 and 2-(12-bromododecyl)-3, 6, 7,1 0, 11-pentahexyloxy-triphenylene were refluxed in a solution of potassium carbonate in acetone to carry out Williamson’s etherification. The final product was finally purified by column chromatography.

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3 Results and Discussion 3.1 FT-IR and 1H-NMR The FT-IR and 1 H-NMR spectra of the final product are presented in Fig. 2. The absence of the O-H and C-Br signals in the FT-IR spectrum, along with the disappearance of the hydroxyl proton signal in the 1 H-NMR spectrum, suggested a successful reaction progression. The increased proportion of protons exhibiting chemical shifts within the range of 4.21–4.25 in the 1 H-NMR spectrum further substantiated the formation of new C-O-C bonds. Moreover, the structure of the final product was confirmed to align with expectations, as inferred from the ratio of protons at various chemical shifts in the 1 HNMR spectrum. The specific spectrum test data is as follows: FT-IR (KBr): vmax/cm-1 2949 (=C-H), 2850 (=C-H), 1261(C-O-C); 1 H-NMRδH: (400 MHz, CDCl3 ): 7.84(12H, s, Ar-H), 4.21–4.25(24H, t, OCH2 ), 1.89–1.97(24H, m, OCH2 CH2 ), 1.75–1.20(48H, m, OCH2 CH2 CH2 + OCH2 CH2 (CH2 )8 CH2 CH2 O), 1.10–0.90(30H, t, CH3 ).

Fig. 2. FT-IR and 1 HNMR of T6C12T4

3.2 DSC and POM The phase transition and liquid crystal properties of the final product T6C12T4 were characterized by DSC and POM techniques. Firstly, the phase transition temperature and interval of the product were determined by differential scanning thermal analysis technique. The liquid crystal texture of the products at different temperatures was then observed under a polarizing microscope with a hot stage. The results are presented in Fig. 3. The final product was heated from room temperature to 200 °C at a ramp rate of 5 °C per minute to eliminate thermal history. Then the first cooling process was carried out, and the final temperature was kept at −25 °C. Finally, the second heating operation is carried out, and the heating was stopped after heating to 180 °C. The experimental data obtained is shown in the figure. During the first cooling process, only an exothermic peak occurred at 101.3 °C. Similarly, only an endothermic peak occurred at 110.9 °C during the second heating process. This indicated that only one phase structure change

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occurred in the product T6C12T4 during the heating and cooling process, which was speculated to be the transition between liquid crystal phase and isotropic phase. In order to further explore the liquid crystal properties of the product, the product T6C12T4 was observed under a polarizing microscope with a hot stage. First, the product was heated from room temperature to 130 °C at a heating rate of 10 °C per minute, and it was observed that the product in the field of view completely changed from a solid state to a dark field, indicating that the transition from solid phase to isotropic phase had been completed; The annealing operation was performed at a cooling rate of 0.1 °C per minute. When the temperature approached 113 °C, the focal conic texture began to appear in the field of view. With the decrease in temperature, the texture in the field of view remained unchanged until it reached room temperature. Based on the texture obtained by POM and combined with the results of DSC, it is reasonable to speculate that the product T6C12T4 undergoes a transition between the columnar phase liquid crystal phase and the isotropic phase around 110 °C.

(1)

(2)

(3)

Fig. 3. (1) DSC curve (2) Polarized texture at 30 °C; (3) polarized texture at 90 °C;

4 Conclusions In conclusion, 1 H-NMR and FT-IR test results confirmed the chemical structure of the product synthesized through a brief chemical reaction process. And the tests of its phase transition, thermal properties and liquid crystal properties, including DSC and POM,

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showed that the dimer product has good liquid crystal properties. It can maintain a liquid crystal phase at room temperature, and has a long liquid crystal interval. The liquid crystal properties of this product suggest potential application prospects in optoelectronic devices and other fields. Acknowledgments. This work is supported by the Beijing Natural Science Foundation (2222055), The Ministry of Education Key Laboratory of Luminescence and Optical Information, Open project (NO. KLLI0BJTUKF2204), BIGC project (NO. Ee202203), (NO. Ec202206), (NO. Eb202201), Discipline construction of material science and engineering (21090123007).

References 1. Kreuder, W., Ringsdorf, H.: The “Wheel of Mainz” as a liquid crystai-structural variation and mesophase properties of trimeric discotic compounds. Angew. Chem. Int. Ed. 26, 1249–1252 (1987) 2. Kumar, S., Varshney, S.K.: Design and synthesis of discotic nematic liquid crystals. Org. Lett. 4(2), 157–159 (2002) 3. Bushby, R., Cammidge, A., Martin, P., et al.: The creation of long-lasting glassy columnar discotic liquid crystals using dimeric discogens. J. Mater. Chem. 9, 1391–1402 (1999) 4. Bacher, A., Bleyl, I., Erdelen, C.H., Haarer, D., Paulus, W., Schmidt, H.W.: Low molecular weight and polymeric triphenylenes as hole transport materials in organic two-layer LEDs. Adv. Mater. 9, 1031–1035 (1997) 5. Kranig, W., Huser, B., Ringsdorf, H., et al.: Phase behavior of discotic liquid crystalline polymers and related model compounds. Adv. Mater. 2(1), 36–40 (1990) 6. Xingtian, H., Chunxiu, Z., et al.: Competition and promotion of different mesophases in a series of novel unsymmetrical discotic dimers via subtle modification of spacers and peripheral side chains. J. Mater. Chem. C 3(5), 589–600 (2017) 7. Huang, L., Ke-Xiao, Z., et al.: Synthesis, self-assembly and optical properties of some rigid π-bridged triphenylene dimers. J. Mater. Chem. C 10, 14453–14470 (2022)

Research on Electroluminescent Structure and Interactive Application Yingmei Zhou(B) and Junwei Qiao Printing and Packaging Department, Shanghai Publishing and Printing College, Shanghai, China [email protected]

Abstract. In recent years,with the rapid development of printed flexible electronics business,as a light-emitting display has been put forward additional requirements such as sensor, interactive and lighting. Electroluminescent devices based on basic structure have received attention in the field of lots of fields such as analysis, wearable application, interactive method, etc. In this paper, the research progress of electroluminescent basic sandwich structure and experimental flatten electrode structure are compared with changed luminescence structure, then flatten electroluminescent structure materials are mainly tested in the application on packaging, in order to play a beneficial enlightenment and guidance role in the field of interactive application. Keywords: Light-emitting display · Sandwich structure · Interactive application

1 Introduction Electroluminescence (EL) is a physical phenomenon where light is generated by an electric field [1, 2]. Alternating current electroluminescent devices (ACEL) means under the driving voltage of the device, holes and electrons are injected from the anode and cathode respectively, and then injected into the luminescent layer through the carrier transport layer to form excitons. Exciton recombination transitions cause the device to emit light [3]. Its basic structure is below in Fig. 1 [4]. Sometimes the basic structure is described as a sandwich structure, where the luminescent layer is set between two electrodes like a sandwich, and at least one side is a transparent electrode to obtain surface luminescence. According to the El structure, the products are printed with phosphor layer, dielectrode layer and electrode layer with two recommend structures [5]. According to lots of research theory, the insulation layer could take effects on the quality of EL products. Screen printing technology is used widely to print EL products, especially in the lab. Thinking of the printing process time, ink thickness and functional quality, the paper try to compare EL thin structure to get practical printing process and get more experimental data for further business application [6, 7]. There are two structures according to commercial applications. The first basic structure includes ITO film, insulator layer, phosphor layer, and top electrode in Fig. 3 [8, 9]. Usually, the thin film EL products use the structure left as below. Right process is © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 385–390, 2024. https://doi.org/10.1007/978-981-99-9955-2_51

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Fig. 1. EL Theory Structure

very complexed because of double insulator layer; however, it is not suitable for each application. Another process without insulator is tested in this paper for farther business products (Fig. 2).

Fig. 2. EL Structure with Insulator Layer (The Left for Simple EL Structure and the Right for Encapsulation Structure)

2 Experimental 2.1 EL Printing Structure The EL structure is designed with Adobe Illustrator software. According to lots study and commended theory with electrode–insulator–phosphor–ITO film [10], the usual printing structure includes two types in Fig. 3.

Fig. 3. Recommend EL Printing Process

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The pattern is designed with AI software for 10*6cm in Fig. 4 below. Considering of screen printing process, each layer should be dried at least 10 min [11]. So the whole process time is so long that we will try reduce insulator layer and print one or two more times phosphor layer. So that the designed pattern changes with experimental setting. 2.2 Output and Comparison In order to get the perfect phosphor layer, this printing process was printed phosphor layer firstly one time, two times, three times and four times, which dried after each time once by once. The measurement tool is PIAS microscope to receive the surface uniform of detail result picture in Fig. 4. The uniform needs to be reflected by grain tile and mottle. These options will influence phosphor layer extinction lighting quality. So compared grains and mottle data with four groups in Table 1.

Fig. 4. Designed Patten with Four Kinds Phosphor Layer

The grainess and mottle are the references to balance the phosphor layer surface. The data showed four types of printing times different toughness. According to ISO 13660, grainess is defined with the density reflection of above 0.4 cycles/mm space frequency in all directions. Because the substrate is smooth ITO film with screen printing output. The only reason caused grainess and mottle is material optical reflection. The more layers we printed, the less grainess and mottle, which means material coating uniform and stability in Fig. 5.

Fig. 5. Phosphor Layer Surface Quality Parameter

After the top electrode is printed on the phosphor layer, these luminescence time and efficiency should be measured. This comparison groups include one group insulator layer together. According to these recorded data, the one or two phosphor layer is so thin that it can’t cover the ITO film very firmly to cause the shortcut. The luminance of lighting of three layers showed feasibility with different time measurement. 24*15 and 24*30

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Options

Time (hours)

Luminance of lighting (Lux)

A (one layer)

24

–

A (one layer)

24*7

–

A (one layer)

24*15

–

A (one layer)

24*30

–

B (two layers)

24

–

B (two layers)

24*7

–

B (two layers)

24*15

–

B (two layers)

24*30

–

C (three layers)

24

236

C (three layers)

24*7

328

C (three layers)

24*15

324

C (three layers)

24*30

325

D (four layers)

24

245

D (four layers)

24*7

252

D (four layers)

24*15

286

D (four layers)

24*30

288

With Insulator Layers

24

235

With Insulator Layers

24*7

305

With Insulator Layers

24*15

310

With Insulator Layers

24*30

323

have the same luminance, which is considered as the reason for electrode silver material drying time. Compared with the insulator layer, the luminance persistence stability of C is proved valuable.

3 Application on Interactive with Flatten Electrodes In order to verify this EL structure feasibility, the product of packaging is obviously can work just as the beginning test. However, the paper focuses on another humidity sensor interactive with EL. Specially this time both electrodes are designed on same layer as comb without insulator also. In terms of EL properties, it is quite easy to print flatten comb pattern electrodes on the PE film. No matter what kind of normal substrate is used, the phosphor material will be extruded smoothly on the top of comb electrodes. Therefore, after printing humidity sensor material, it can respond after such humidity environment in Fig. 6.

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Fig. 6. Outline Design Sketch (The Left for Orignal Design and the Right for Printed Result)

The sensitive material could affect the respond speed without insulator material option.Through screen printing process, the basic structure without insulator layer is more suitable for the production of EL.

4 Conclusion Through the experiment of the simulate on screen printing, the research gets the output of EL application without insulator layer in sandwich structure. Many tests focus on the support on the base. The printing process compared the uniform grainess, mottle, lighting time and Luminance of lighting, the result proved our test. So it is important to real application for its process reducing specially for screen printing. The second experimental is flatten comb electrodes shape. The quality of humidity sensor with El structure is very successful, which showed perfect real-time exhaled humidity response. The test reduced layers of EL, which can dig out more application such as mask, AI wearable clothing fields. Last, there are more types substrates for EL printing, for example PI. ITO, PVC, etc. In a word, with the development of technology, there are still some problems such as large commercial fields, personalization, material, and so on. Hope this study could push more business products into the market application. Acknowledgements. The paper is supported by Key Lab of Intelligent and Green Flexographic Printing (ZBKT202102).

References 1. Zhang, Z., Cui, L., Shi, X., et al.: Textile display for electronic and brain-interfaced communications. Adv. Mater. 30(18), 1800323.1-1800323.8 (2018) 2. Tachibana, S., et al.: A printed flexible humidity sensor with high sensitivity and fastresponse using a cellulose nanofiber/carbon black composite. ACS Appl. Mater. Interfaces 14, 5721– 5728 (2022) 3. Lei, D., et al.: Self-powered graphene oxide humidity sensor based on potentiometric humidity transduction mechanism. Adv. Funct. Mater. 32, 2107330 (2022)

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4. Lu, Y., Yang, G., Shen, Y., Yang, H., Xu, K.: Multifunctional flexible humidity sensor systems towards noncontact wearable electronics. Nano-Micro Lett. 14, 1–34 (2022) 5. Meng, X., Yang, J., Liu, Z., Lu, W., Sun, Y., Dai, Y.: NonContact, fibrous cellulose acetate/aluminum flexible electronicsensor for humidity detecting. Compos. Commun. 20, 100347 (2020) 6. Lv, C., et al.: Sensitively humidity-driven actuator based on photopolymerizable PEG-DA films. Adv. Mater. Interfaces 4, 1601002 (2017) 7. Taccola, S., Greco, F., Sinibaldi, E., Mondini, A., Mazzolai, B., Mattoli, V.: Toward a new generation of electrically controllable hygromorphic soft actuators. Adv. Mater. 27, 1668– 1675 (2015) 8. Zhu, P., et al.: Flexible and highly sensitive humidity sensor based on cellulose nanofibers and carbon nanotube composite film. Langmuir 35, 4834–4842 (2019) 9. Li, F., Li, P., Zhang, H.: Preparation and research of a highperformance ZnO/SnO2 humidity sensor. Sensors 22, 293 (2022) 10. Duan, Z., et al.: Daily writing carbon ink: novel application on humidity sensor with wide detection range, low detection limit and high detection resolution. Sens. Actuators B Chem. 339, 129884 (2021) 11. Geffroy, B., Roy, P.L., Prat, C.: Organic light-emitting diode (OLED) technology: materials, devices and display technologies. Polymer Int. 55(6), 572–582 (2006)

Synthesis and Properties of Pentyloxy Triphenylene Bridged Tetraphene Maoxin Zhang1 , Yi Fang1,1(B) , Chunxiu Zhang1 , Ruijuan Liao1 , Yuguang Feng1 , Ao Zhang2 , Xiaoli Song1 , and Yinjie Chen1 1 School of Printing and Packaging Engineering, Beijing Institute of Graphic Communication,

Beijing 102600, China [email protected] 2 School of Basic Education, Beijing Institute of Graphic Communication, Beijing 102600, China

Abstract. In this paper, a kind of organic photoelectric material was designed and synthesized by flexible alkyl chain connection with pentyloxy-triphenylene and tetraphene. The synthesized molecular structure was confirmed by 1 H-NMR and FT-IR. Differential scanning calorimetry (DSC) and polarizing microscope (POM) were used to determine that they did not have liquid crystal properties, and the absorption peak was determined by ultraviolet absorption. Fluorescence spectra showed that they did not have AIE effect, and the liquid crystal properties and AIE properties of their respective moieties were disturbed by the alkoxy bridge between pentoxy-triphenylene and tetraphene. However, the mechanism of action that causes this is not clear. Keywords: Liquid Crystal · Triphenylene · Tetraphene · AIE

1 Introduction Pentaoxy-triphenylene is a discotic liquid crystal molecule with high charge conductivity. However, its luminescence is quenched due to aggregation caused by π-π stacking interactions, leading to the phenomenon of aggregation-induced quenching (ACQ). Aggregation-induced emission (AIE) is a phenomenon where AIE molecules emit fluorescence when in the aggregated state, while exhibiting weak or no luminescence in dilute solutions. It was first discovered by Professor Tang Benzhong’s research group in 2001 [1], and typical AIE molecules include diphenylacrylonitrile and tetraphenylethene. By rationally connecting AIE moieties with pentaoxy-substituted triphenylene, AIE liquid crystals can be formed. This study designed and synthesized a molecule with pentaoxy-substituted triphenylene as the liquid crystal core, alkoxyl groups as the bridging chains, and tetraphenylethene as the AIE moiety, to investigate whether it simultaneously possesses both AIE and liquid crystal properties.

© The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 391–396, 2024. https://doi.org/10.1007/978-981-99-9955-2_52

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2 Experimental All chemical reagents are purchased from Beijing Ouhe Technology Co., LTD. (Fig. 1).

Fig. 1. Synthesis pathway of 5H4T

Compound 2 (pentaoxy-triphenylene, HAT5) was synthesized through the Williamson etherification reaction and Scholl reaction using hydroquinone and 1bromopentane as reactants. Subsequently, compound 3 was obtained from HAT5 under the catalytic action of borane. Compound 4 was then synthesized through the asymmetric etherification of compound 3 [2]. Compound 5 (4-hydroxy-tetraphenylethene) was obtained by the McMurry coupling reaction of benzophenone and hydroxybenzophenone [3]. Reaction between compound 4 and compound 5 yielded compound 5H4T.

3 Results and Discussion 3.1 FT-IR and 1 H-NMR of 5H4T The compound was confirmed to be the target product by FT-IR and 1 H-NMR(Fig. 2). FTIR (KBr): vmax/cm−1 2956 (C-H), 2860 (C-H), 1616 (C = C), 1262(C-O-C); 1 HNMR δH (400 MHz, CDCl3 ): 7.84 (s, 6H, Ar-H), 7.11–7.01 (m, 14H, Ar-H), 6.93–6.91 (d, 2H, Ar-H), 6.66–6.64 (d, 2H, Ar-H), 4.29–4.22 (m, 12H, OCH2 ), 4.02–4.01 (d, 2H, OCH2 ), 2.10–1.98(d, 4H, CH2 CH2 ), 1.97–1.91 (m, 10H, OCH2 CH2 ), 1.56–1.41 (m, 20, OCH2 CH2 CH2 , OCH2 CH2 CH2 CH2 ), 1.00–0.92 (m, 15H, CH3 ).

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Fig. 2. FT-IR and 1 H-NMR of 5H4T

3.2 Liquid Crystal Properties of Compound 5H4T The compound was investigated for its liquid crystalline behavior by recording phase transition data using a differential scanning calorimeter (DSC) and observing the texture under a polarized optical microscope (POM) equipped with a heating stage. The DSC results, as shown in the Fig. 3, indicate that the sample does not exhibit significant endothermic peaks during the second heating cycle. Additionally, there were no noticeable exothermic peaks during the first cooling cycle. As shown in the Fig. 4, the product was heated on the heating stage and observed under a polarized optical microscope at a heating rate of 10 °C/min. As 5H4T was heated from room temperature to 80 °C, it completely transformed into an isotropic phase. Upon cooling, there was no evidence of birefringence characteristic of a liquid crystal phase. This suggests that compound 5H4T does not possess liquid crystalline properties.

Fig. 3. The DSC image of 5H4T

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Fig. 4. The POM image of 5H4T

3.3 Optical Properties of 5H4T A solution of 5H4T with a concentration of 3 × 10−5 M in dichloromethane was prepared for UV-Vis absorption spectroscopy. As shown in Fig. 5, the absorption spectrum of 5H4T exhibits two distinct absorption peaks in different regions. The first peak is observed between 220–284 nm with peak values at 235 nm, 259 nm, 269 nm, and 277 nm, while the second peak is observed between 296–318 nm with a peak value at 308 nm. The absorption peaks at 259 nm, 269 nm, and 277 nm are characteristic of the triphenylene moiety, while the peaks at 235 nm and 308 nm correspond to the tetraphenylethene (TPE) moiety [4]. Compared to the monomers, compound 5H4T exhibits absorption in both the UV and visible light regions, with a slightly expanded absorption range. This analysis of the UV-Vis absorption spectrum provides insights into the optical properties of compound 5H4T.

Fig. 5. Ultraviolet absorption spectra of 5H4T and HAT5

TPE itself exhibits AIE properties. When it is bridged with an alkyl chain to form the compound with pentaoxy-substituted triphenylene, does it retain AIE properties? We tested the relationship between fluorescence intensity and aggregation by adding a poor solvent, water, to its THF solution. In a water-free THF solution with a concentration of 3 × 10−5 M, as different volume fractions of water (fw ) were added, the fluorescence intensity of the solution decreased. This indicates an aggregation-caused quenching (ACQ) behavior. It suggests that the interaction between pentaoxy-substituted triphenylene and tetraphenylethene, mediated by the alkoxyl bridge, not only affects the formation of the

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liquid crystalline state of pentaoxy-substituted triphenylene but also influences the AIE properties of tetraphenylethene (Fig. 6).

Fig. 6. 5H4T fluorescence spectrum

4 Conclusion It can be inferred from the studies on the liquid crystal properties and luminescence properties of 5H4T that TPE and HAT5 disturb the liquid crystal properties of HAT5 and the AIE properties of TPE through the bridging of alkyl chains, indicating that the bridging chain is crucial to the molecular design of aggregation-induced luminescent liquid crystals. Although it does not have the performance of luminous liquid crystals, it can cause people to think about how the performance of liquid crystals and AIE performance promote each other rather than disturb each other. Acknowledgments. This work is supported by the Beijing Natural Science Foundation (2222055), Discipline construction of material science and engineering (21090123007), The Ministry of Education Key Laboratory of Luminescence and Optical Information, Open project (NO. KLLI0BJTUKF2204), BIGC project (NO. Ee202203), (NO. Ec202206), (NO. Eb202201), 2022 Beijing Municipal University Teacher Team Construction Support Plan Excellent Young Talents Project (BPHR202203071).

References 1. Jin, R., Zeng, C., Zhou, M., et al.: Atomically precise colloidal metal nanoclusters and nanoparticles: fundamentals and opportunities. Chem. Rev. 116(18), 10346–10413 (2016) 2. Zhang, W., Zhang, S., Zhang, Z., et al.: 2D organic superlattice promoted via combined action of π–π stacking and dipole-dipole interaction in discotic liquid crystals. J. Phys. Chem. B 121(31), 7519–7525 (2017)

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3. Duan, X.-F., Zeng, J., Lü, J.-W., et al.: Insights into the general and efficient cross mcmurry reactions between ketones. J. Organ. Chem. 71(26), 9873–9876 (2006) 4. Cai, Y., Du, L., Samedov, K., et al.: Deciphering the working mechanism of aggregationinduced emission of tetraphenylethylene derivatives by ultrafast spectroscopy. Chem. Sci. 9(20), 4662–4670 (2018)

Research Progress and Applications of Electrochromic Materials and Devices Jinyu Zeng, Yue Mo, Xin Li, and Guangxue Chen(B) State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou, China [email protected]

Abstract. As a functional material, electrochromic materials can change their color by regulating the absorption or reflection of light at a small driving voltage. According to the characteristics of color control, electrochromic devices have shown great potential in the fields of green buildings, intelligent displays, energy storage equipment, and military camouflage. Despite the continuous progress in related fields, how to make electrochromic devices truly achieve the ideal comprehensive performance has always been a long-term issue. This paper briefly summarizes the types and mechanisms of electrochromic materials, then introduces the basic structure composition and characteristic requirements of electrochromic devices. Reviewing the main problems faced in the applications of electrochromic devices, such as long response time, insufficient coloration efficiency, poor cycle stability, and insufficient durability. What’s more, the latest ideas and achievements proposed to solve these problems are summarized, hoping to enlighten readers. Finally, the future development direction of electrochromic technology is prospected. Keywords: Electrochromic materials · Electrochromic mechanism · Electrochromic devices · Applications and prospects

1 Introduction Electrochromism is a phenomenon where the color or optical properties (transmission, reflection, or absorption) of a material change steadily and irreversibly when an external voltage is applied [1]. Substances with electrochromic properties are called electrochromic materials, and the devices composed of electrochromic materials are called electrochromic devices (ECDs). In the 60s of the 20th century, American scientist S.K. Deb was the first to discover the phenomenon of WO3 [2]. Subsequently, researchers have conducted a lot of experiments on this as people began to pay attention to electrochromic materials. Various electrochromic materials were reported and a wide range of electrochromic devices were made in the following time. So far, electrochromic technology has been applied in many fields, such as smart windows, aircraft windows, adaptive camouflage, energy storage, and display [3–6].

© The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 397–407, 2024. https://doi.org/10.1007/978-981-99-9955-2_53

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2 Electrochromic Materials Electrochromic materials can be divided into three categories: inorganic electrochromic materials, organic electrochromic materials, and composite electrochromic materials. The early research mainly focused on inorganic electrochromic materials, which are representative of transition metal oxides and their hydrates [7]. Organic electrochromic materials mainly include polymers such as polyaniline, polythiophene, and polypyrrole [8–10]. Small molecules like viologens [11] as well as some metal-organic complexes, such as Prussian blue [12] are also contained. 2.1 Inorganic Electrochromic Materials Since the electrochromic phenomenon was discovered, researchers have done a lot of research to explore the mechanism. Next, a series of color-tuning mechanisms were proposed, including the Deb model [13], the Faughnan model [14], and the Schiemer model [15]. The Faughnan model is currently accepted, which holds that the 3d and 4f orbital electrons from the oxides of transition metals are unstable. Under the action of the applied voltage, the valence status can be changed easily by the double injection/extraction of electrons and electrolyte ions. It can form the phenomenon of the coexistence of mixed valence ions. Meanwhile, the color of the material varies when the ion valence state and blending ratio are changed. According to the difference in color-tuning, the oxides of transition metals can be divided into cathodic electrochromic materials and anodic electrochromic materials. The metal elements in anodic electrochromic materials are mostly concentrated in groups VII.B and VIII., and the color-tuning mechanisms are: An MOx (Fading state) ↔ MOx (Shading state) + nA− + ne− Formula: A− is an anion, such as OH− , X− (halogen ion) in the electrolyte, etc.; M is a transition metal element. The metal elements in cathodic electrochromic materials are mostly concentrated in groups IV.B ~ VI.B, and the color-tuning mechanism is: MOx (Fading state) + nA+ + ne− ↔ An MOx (Shading state) where A+ is a cation, such as H+ in the electrolyte, alkali metal ions, etc. When making inorganic electrochromic devices, metal oxides are generally deposited on a conductive substrate to form a thin and uniform film. It should be noted that the physical morphology of the film has a big impact on the overall performance towards the device. To improve the physical morphology of the film, Wanget al. [16] constructed WO3 -RE(RE = Ce, Eu, Sm, and Gd) nanofilms doped with rare earth elements (RE) on fluorine-doped tin oxide (FTO) glass electrodes by one-step hydrothermal technology. WO3 -RE nanomembranes exhibit an excellent contrast ratio, good cycle stability, and high surface capacitance due to their fast ion transfer rate and stable membrane structure. Hou et al. [17] prepared tin-doped nickel oxide (Sn-doped NiO) porous electrochromic film, which significantly improved the performance of NiO films compared with the

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undoped films. The doped films have better properties such as less response time (bleaching/fading time 0.4 s, coloring time 3.0 s), high coloring efficiency (48.9 cm2 C−1 ), and long cycle lifetime (30,000 cycles). 2.2 Organic Electrochromic Materials Organic electrochromic materials have the advantages of a wide range of color transformation, high material conductivity, and chemical modification, so they have been valued by researchers. The structure of polymers is characterized by the existence of conjugated π electronic structures. Because of the injection of charge, the π electrons have a large conjugated delocalization system. The main representatives are polyaniline, polypyrrole, polythiophene, and poly-furan [18]. Their molecular structure is shown in Fig. 1.

Fig. 1. The structural formulas of the polymers

Metal-organic complex electrochromic materials, also known as metal-organic chelates, are characterized by metal-ligand charge transfer effects, which are generally accompanied by strong color transformations that reflect higher and very wide absorption bands in the UV-Vis spectrum [19]. The most common is phthalocyanine, which is widely used in dyes, coatings, and photocatalysis. The structure of phthalocyanine is shown in Fig. 2:

Fig. 2. The structure of phthalocyanine

Viologen is a typical oxidized reduced organic electrochromic material [20], and its electrochromic mechanism is shown in Fig. 3:

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Fig. 3. Three redox states and reversible tautomerism of viologen

Organic electrochromic materials have been mostly researched in recent years, but there are bottlenecks such as single materials, low color contrast, and poor stability. To improve the contrast ratio and cycling performance of polythiophene, Zhang et al. [21] adopted a molecular design method to introduce benzene rings into the polythiophene main chain. The addition of benzene rings made the electrochromic film more coarse and loose. This approach facilitates the diffusion, migration, and charge transfer reactions of ions in the membrane, thereby improving device performance. Qin et al. [22] prepared porous membranes with better-infrared modulation ability by doping polyaniline with copper ions, which provided a new way to improve the infrared modulation ability of electrochromic devices based on polyaniline conductive polymers. To solve the problem of bad redox stability caused by the irreversible aggregation from free radical viologen, Wu et al. [23] inhibited the autopolymerization of radical viologen by introducing ionic liquids, and prepared semi-interpenetrating bipolymer network (DPN) organic gels for enhancing the cycle stability of the electrochromic devices. 2.3 Composite Electrochromic Materials Composite electrochromic materials are an effective means for the performance defects of existing single electrochromic materials. The composites can include inorganic/electrochromic materials, inorganic/organic electrochromic materials, or organic/organic electrochromic materials. WO3 and TiO2 account for the majority of inorganic/inorganic electrochromic materials, such as WO3 /TiO2 , TiO2 /NiO, etc. [16, 24, 25]. To enrich the color display of the device, Wang et al. [25] used WO3–x and other inorganic electrochromic materials to prepare a device with multicolor. The transmittance and color of the device were controlled by adjusting the number of layers of co-assembled nanowires. Nguyen et al. [26] used WO3 doping to enhance the stability and electrochromic performance of polyaniline (PANI) electrochromic windows. The PANI-WO3 composite thin-film device based on PANI-WO3 composite film device has a short response time (both 1.5 s for coloring time and bleaching/fading time), high coloration efficiency (195 cm2 C−1 ), long lifetime (more than 1000 cycles), and more colorful colors.

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3 Electrochromic Devices Typical electrochromic devices are composed of transparent conductive substrates, an electrochromic layer (solid-state), an ion conductive layer (solid-state), and an ion storage layer (solid-state). The device is stacked, as shown in Fig. 4. The entire device needs to be hermetically sealed usually [27], but there are also “sandwich” structures when the electrolyte is liquid, as shown in Fig. 5.

Fig. 4. The structure of conventional laminated transmission electrochromic devices

Fig. 5. Electrochromic devices of “Sandwich” structure

The transparent conductive layer should have two features with good electronic conductors and high light transmittance at least. FTO glass and ITO glass are common conductive substrate materials used as ECD electrochromic film layers [28], which have the advantages of high transparency and low resistance but have the disadvantages of poor flexibility. Based on this, PET, which has good flexibility, is also selected as a transparent conductive substrate for electrochromic materials [29]. The electrochromic layer refers to the EC layer, also known as the working electrode (WE). As for the core part of electrochromic devices, the EC layer should have the advantages of high ion or electron conductivity, large optical contrast of colored state and bleached state, etc. The performance of electrochromic devices mainly depends on the layer [30, 31]. The ion storage layer can also be called the counter electrode (CE) layer, the role of the layer is to store and provide the ions required by the electrochromic material. Under the action of the external electric field, the ions are implanted into the EC layer, and the CE layer releases ions to provide the electrolyte layer. When the reverse electric field is applied, the electrochromic layer sheds ions, at this time the CE layer stores these ions. The opposite oxidation or reduction process occurs under the action of an electric field.

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The electrolyte layer, also known as the ion transport layer, is a transport channel that provides ions for the electrochromic effect. Electrolytes need to have high ionic conductivity, light transmittance, and electrochemical stability. The common electrolytes can be divided into solid, liquid, and semi-solid according to different morphologies. Although liquid electrolytes have high ionic conductivity and can provide rapid colortransformation response for ECDs, they are difficult to package, easy to leak, and have poor chemical stability. Instead, all-solid-state electrochromic devices are becoming the choice [32].

4 Electrochromic Device Applications The application research of electrochromics has been developing rapidly and has been applied to many fields. Some products are beginning to be practical and may bring great business value (Fig. 6).

Fig. 6. Electrochromic device applications

4.1 Electrochromic Smart Windows Electrochromic smart windows automatically adjust color and temperature to achieve the purpose of improving natural light intensity. It has the advantages of high efficiency, low energy consumption, and green environmental protection, which reduces energy consumption to a certain extent [33]. In the 80s of last century, the C. G. Granqvist [34] team proposed the technology of using WO3 film as the window glass coating to realize the dynamic adjustment of radiation energy in buildings. The emergence of smart windows became a milestone in the field of electrochromic applications. Theory shows that nanostructured materials with small sizes and large specific surface areas can help shorten ion diffusion length, enhance electrolyte accessibility, and improve the performance of electrochromic devices. Commonly used electrochromic nanoparticle preparation methods include magnetron sputtering method, electrochemical deposition method, sol-gel method, all-solvent method, etc. To make the smart window have highquality electrochromic performance, the researchers started with process optimization and material design. An et al. [35] introduced ITO nanoparticles into WO3 nanosheets by an all-solvent method to construct electrochromic nanocomposite smart windows.

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The addition of ITO nanoparticles helped to build richer electron transport channels. The electrochemical activity and conductivity of composite films were enlarged. The device showed higher optical modulation (up to 88%) and an awesome coloration efficiency (154.16cm2 C−1 ). Ahmad et al. [36] prepared Ni-WO3 (Ni-doped) film by sol-gel method. The addition of Ni brings the excellent performance of WO3 and shows good cycle stability in more than 20,000 cycles. To further improve the energy-saving needs of smart windows and meet individual needs, dual-band electrochromic technology that can regulate both visible light and near-infrared appeared. Wang et al. [37] used polyaniline as a material, by electrochemical deposition, uniform PANI film on ITO glass, and observed this electrochromism in single-component organic materials for the first time. 4.2 Electrochromic Display Electrochromic displays work on the basis of an electrochemically driven. The optical properties of devices will change within the redox process of electrochromic materials. Electrochromic displays are non-luminous displays, that do not cause eye fatigue even if viewed for a long time. In addition, electrochromic displays are characterized by flexibility and transparency. What’s more, it is suitable for many substrates. In recent years, researchers have used electrochromic displays in flexible wearable devices [38] to meet the increasing demand for laminable and stretchable displays. The ideal electrochromic displays should have a shorter response time for fast information display/switching, good stability, and long lifetime, and higher optical modulation to guarantee a pleasant reading experience. However, there are still some performance defects, such as responsiveness and durability, which are related to electrochromic materials and processing technology. Typically, metamaterial-based electrochromic displays use traditional device structures, including metamaterial working electrodes, electrolyte layers, and transparent counterelectrode layers with different structural colors. Since the electrolyte and counter electrode are blocked by the WE, it will inevitably lead to incident and reflected light loss, and eventually cause a decrease in the reflectivity (luminance) of the device and a serious deviation in chromaticity. In response to this problem, Zhao et al. [39] established a Fabry-Perot (FP) nanoresonator on the top surface of the porous Nylon-66 film. Instead, the electrolyte and counter electrode were placed on the back. This design avoids the use of precious metals and complex nanofabrication technologies, with great potential for expansion in terms of cost and compatibility with existing electrochromic manufacturing facilities, which implements good color quality with no color change or luminance drop. Vanadate is used in ECDs due to its rich coloring range, causing poor cycle stability due to its dissolution in aqueous solutions. The problem of vanadate dissolution was solved with the help of designing a mixed electrolyte composed of tetraethylene glycol dimethyl ether and water [40]. The electrolyte can form a sturdy cathodic electrolyte interface layer on the vanadate electrode. The prepared potassium vanadate (K2 V6 O16 ·1.5H2 O, KVO) with larger layer spacing also showed better electrochromic properties than sodium vanadate (NaV3 O8 ·1.5H2 O, SVO), and improved the long-term stability of ECD. To improve the durability of the device, some researchers have focused on the ability of self-healing the. Kim [41] et al. report a multi-crosslinked network hydrogel (MCNH) composed of hydrophilic and hydrophobic waters. The material is imparted with self-healing ability by introducing cross-linking agents and ionic coordination bonds.

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4.3 Electrochromic Energy Storage Devices In the field of energy applications, various energy technologies need to be produced, and energy should be used more intelligently and efficiently. The intelligent electronic devices of the future are also moving towards lightweight, transparent development. Many supercapacitor electrode materials exhibit electrochromic effects, such as transition metal oxides W, Ni, Co, Ti, V, and conductive polymers polyaniline (PANI), polypyrrole (PPy), etc. This enables supercapacitors to combine high power density and long-cycle performance with electrochromic properties [42]. For example, Shao et al. [43] prepared TTCB, TBTCB, and TECB with star structure, and made them into new hybrid films to make supercapacitors, in which pTBTCB showed good electrochromic and energy storage performance (4.53 mF·cm−2 ). Cong et al. [44] prepared metal-organic coordination polymers by the mutual coordination of iron salts and triphenylamine functionalized phenanthroline ligands, which were used as supercapacitor electrodes, and the synergy between iron ions and triphenylamine as the double redox action center in the electrode made the electrode maintain good energy storage performance while having a uniform and significant discoloration effect. Liu et al. [45] use optical radiation to prepare α-MoO3-x nanosheets on a large scale in two minutes and apply them to supercapacitor electrodes, which have a large optical contrast of 40.2% at 650 nm, fast coloring, bleaching response times, good coloration efficiency (30.4 cm2 C−1 ) and high specific capacitance (80 F/g). Mustafa et al. [46] used the response surface method and central composite design (RSM/CCD) to optimize the application of nickel-cobalt phosphate (NiCoPo4 ) composites for the most electrochromic supercapacitors, and prepared nickel-cobalt phosphate (NiCoPo4 ) by microwave-assisted method, which generated a transition from light green to black when the voltage change was (0–0.5 V), achieving a coloration efficiency of 48.95 cm2 C−1 and a high specific capacitance of 262.9 F/g. 4.4 Adaptive Camouflage Devices Electrochromic materials have fixed infrared radiation characteristics for mid-infrared and far-infrared rays. The modularable properties of optics and thermal make it can be designed as an infrared radiation devices. It has been used in military weapons and electronic equipment. In addition, flexible wearable electrochromic devices with high performance have also developed rapidly and made gratifying progress [47]. Zhang et al. [48] grow in situ a novel photopolymeric blue-phase liquid crystal with cubic nanostructure on a highly oriented MXene nanostructured film, which can realize the transition from color to deep black under a low DC electric field. An electrochromic flexible was prepared film from this material, which has excellent electrothermal conversion and low mid-infrared color yield and can be used for thermal camouflage. To solve the problems of the relatively complicated preparation process of multi-color electrochromic materials in adaptive camouflage, Wang et al. [49] propose a new scheme to realize the multi-color electrochromic performance of transition metal oxides. That is, by precisely adjusting the experimental conditions, bivalent Vx O2x+1 (x > 2) transition metal oxides containing V4+ and V5+ were prepared, and uniform modification of Au nanoparticles was achieved by in situ reduction, and Au/ with bivalent nanoflower-like structure was

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obtained Vx O2x+1 (x > 2). Under the synergistic effect of the bivalent state, the material achieves the excellent electrochromic performance of gray, blue, green, yellow, and orange-red color changes at less than 1.5 V, which is highly similar to a variety of scenes in nature, has significant active camouflage characteristics, and the electrochromic material also has excellent cycle stability performance (the electrochromic performance can be maintained to 95% after 2000 cycles).

5 Summary With the development of the times, electrochromic technology has received more and more attention. This paper mainly reviews the composition and development of electrochromic materials and their devices. There are still many problems in electrochromic materials, such as single color, long color switching time, poor stability, and high cost. In terms of electrochromic devices, there are many difficulties in the response sensitivity and long-term stability of the device. The key to realizing the practical application of electrochromic devices lies in the stability and functional diversification of electrochromic materials, the conductivity and optical transparency of transparent conductive layers, the ionic conductivity of electrolytes, electronic insulation, and environmental safety, and the long-term stability of devices. It is believed that with the advancement of science and technology, the current problems will be solved, and electrochromic technology will also bring us greater benefits.

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Preparation and Adsorption Performance of Heavy Metal Ions of a Complex Hydrogel of Oxidized Nanofibrillated Cellulose/Cationic Guar Gum Ci Song1,2(B) , Yunfei Bao1 , Yong Lv1,2(B) , and Deng Ye1,3 1 School of Engineering and Information, Yiwu Industrial and Commercial College, Yiwu,

Zhejiang, China [email protected], [email protected] 2 School of Light Indurstryand Engineering, South China University of Technology, Guangzhou, Guangdong, China 3 Zhejiang Lanyu Digital Technology Co., Ltd., Yiwu, Zhejiang, China

Abstract. Nanocellulose, a rich source of natural biomass materials, has dual characteristics of green and environmentally friendly performance and nanomaterials. It presents some potential applications in the field of heavy metal pollution control in water systems. In this study, oxidized nanofibrillated cellulose (ONFC) was prepared by oxidation of nanofibrillated cellulose (NFC) with sodium periodate. ONFC was compounded with cationic guar gum (CGG) to prepare ONFC/CGG complex hydrogel. To evaluate the adsorption performance on heavy metal ions, Cu2+ was selected to evaluate the adsorption performance. The results showed that the appropriate pH range of the solution system was 3.5–6. As the pH of the solution increased, the ionization of the complex aerogel enhanced the electrostatic attraction between the cations and the aerogel surface, resulting in greater adsorption. With the constant increase of intital concentration, the maximum absorption capacity of ONFC/CGG hydrogel for Cu2+ was also constantly increasing. When the intital concentration of Cu2+ reached 120 mg/L, the maximum adsorption capacity of the hydrogel for Cu2+ ions tended to be saturated. It demonstrates that ONFC/CGG hydrogel had a high adsorption efficiency for Cu2+ . When the sorption time was 4 min, the adsorption became saturated, and the maximum adsorption capacity could reach 452.3 mg/g. This study has shown that ONFC/CGG hydrogel has a wide range of raw material sources and low cost. When absorbing heavy metal ions by the hydrogels, the pH value has a wide range. Meantimes, the adsorption efficiency is high. It has wide application prospects in the field of heavy metal pollution control in water systems. Keywords: Nanofibrillated Cellulose (NFC) · Cationic Guar Gum (CGG) · Complex Hydrogel · Heavy metal ions

© The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 408–412, 2024. https://doi.org/10.1007/978-981-99-9955-2_54

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1 Introduction Various heavy metal ions are contained in industrial wastewater, such as Pb2+ ,Cu2+ ,Zn2+ ,Hg2+ ,hetc., which can seriously influnce human health. It is of great significance to remove and recycle heavy metal ions in wastewater. At present, the main treatment methods include adsorption method, membrane separation method, solvent extraction method, ion exchange method, etc. [1]. Among them, the adsorption method is widely used, which mainly uses porous adsorption materials to remove heavy metals in wastewater. Bio-flocculants have the advantages of non-toxicity, high efficiency, and no secondary pollution. Biosorbents, low in cost and no secondary pollution, can selectively remove heavy metal ions at lower concentrations, which are promising heavy metal ion adsorbents [2]. Cellulose-based sorbents are a type of “green” sorbent. NFC is rich in sources. It also has the characteristics of nanomaterials, showing its application potential in the field of heavy metal pollution control in water systems [3]. At present, most chemical modifications of cellulose nanofibrils on heavy metal pollution control in water systems are not environmentally friendly, which leads to the second-pollution in water systems. In this study, sodium periodate was used to oxidize nanofibrillated cellulose to prepare oxidized nanofibrillated cellulose(ONFC). ONFC was compounded with cationic guar gum(CGG) to prepare ONFC/CGG hydrogel. The above modification methods, which had no second-pollution, were used to improve the comprehensive adsorption capacity of the complex hydrogel.

2 Experimental 2.1 Materials and Methods Nanofibrillated Cellulose (the NFC content is 2wt%. The length of NFC is 100–800 nm. The diameter of NFC is 20–40 nm) is provided by Zhejiang jinjiahao green nano materials Co., Ltd. Cationic guar gum is purchased from Wuxi Jinxin Group Co., Ltd. Sodium periodate (NaIO4 ), sodium hydroxide (NaOH), ethylene glycol, hydrochloric acid (HCl) and other reagents are bought from Sinopharm Chemical Reagent Co., Ltd. 2.2 Preparation of the Complex Hydrogel ONFC/CGG 200 g of NFC aqueous solution with 1wt% NFC was put into a light-shielding brown three-neck flask and stirred mechanically. Sodium periodate aqueous solution with the molar ratio of NaIO4 to the anhydroglucose unit of NFC 1:1 was added to oxidize and modify NFC. Different mass fractions of ONFC solutions were added to 100 g CGG solution. Then it was homogeneously dispersed and stirred in a water bath at 60 °C for 1 h. Finally, ONFC/CGG complex hydrogel was obtained (the content of CGG was 1wt%).

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2.3 Determination of Adsorption Performance of ONFC/CGG Complex Hydrogel Under a certain pH condition, 10 mL of a certain concentration of Cu2+ solution was put into the sample bottle and stirred on a table, then 10 mL of 0.3 g/L ONFC/CGG complex hydrogel dispersion was put into the sample bottle, stirred and adsorbed at a speed of 200 rpm for a certain sorption time. When the adsorption was over, an appropriate amount of supernatant was filtered with a nylon filter head with a pore size of 0.2 µm. (Atomic Absorption Spectrum)AAS was used to evaluate the absorbance of the residual concentration of Cu2+ . Qe was employed to evaluate the adsorption performance of heavy metal ions [4]. The Cu2+ concentration was obtained from the Cu2+ standard curve. Three parallel experiments were performed for each single variable condition.

3 Results and Discussions 3.1 Effect of the pH Value of the Aqueous Solution on Cu2+ Adsorption Performance of ONFC/CTS Complex Hydrogel The pH of the aqueous solution affected both the speciation of metal ions and the surface charge of the adsorbent, which result in affecting the adsorption (Fig. 1).

Fig. 1. The relationship between Qe and the Fig. 2. The relationship between Qe and the pH value of the solutions pH value of the solutions

The Cu2+ solution started to spontaneously precipitate Cu (OH)2 when the pH value was above 6.0. Therefore, the adsorption performance was tested in the pH range from 2 to 6. The ionization of nanocellulose enhanced the electric attraction between cations and the aerogel surface. When the pH was below 3.5, the adsorption capacity increased from 182.2 mg/g to 420.7 mg/g. When the pH ranged from 3.5 to 6.0, the adsorption amount increased slightly, which was attributed to the protonation and deprotonation process of the carboxyl group. When the pH was below 3.5, the increase of pH had a greater impact on the deprotonation of carboxyl groups. Therefore, the adsorption capacity of ONFC/CGG complex hydrogel increased significantly. When the pH was above 3.5, the degree of deprotonation of carboxyl groups remained basically unchanged. When the pH continues to increase, the adsorption capacity of ONFC/CGG hydrogel remained basically unchanged. The relatively suitable range of pH value was 3.5–6.

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3.2 Effect of the Initial Concentration of Cu2+ Solution on the Adsorption Performance of ONFC/CTS Composite Hydrogel It can be seen from the Fig. 2 that the maximum absorption capacity of ONFC/CGG hydrogel for Cu2+ increased with the constant increase of the initial concentration (C0 ) of the solution. When the initial concentration of Cu2+ was below 120.0 mg/g, the adsorption capacity increased rapidly. When the concentration reached 120.0 mg/L, the hydrogel reached adsorption equilibrium for Cu2+ ions. It showed that the increase in adsorption capacity slowed down and reached adsorption saturation when the intital concentration was above 120.0 mg/g. 3.3 Effect of Sorption Time on the Adsorption Performance of ONFC/CGG Complex Hydrogel Adsorption efficiency is an important indicator for evaluating heavy metal adsorbents. Adsorbents that can quickly reach the adsorption target in a short time are conducive to saving time and economic costs. Effect of sorption time on the adsorption performance of ONFC/CGG complex hydrogel was shown in Fig. 3. When sorption time was less 4 min, the adsorption capacity of the complex hydrogel increased rapidly. With the prolongation of the sorption time, the adsorption capacity remained basically unchanged. Therefore, the adsorption of Cu2+ by ONFC/CGG complex hydrogel could reach equilibrium within 4 min. The maximum adsorption capacity could reach 452.3 mg/g.

Fig. 3. Effect of sorption time on the adsorption performance of ONFC/CGG complex hydrogel

4 Conclusions In this study, the ONFC/CGG complex hydrogel was obtained by compounding oxidized nanofibrillated cellulose(ONFC) with cationic guar gum(CGG). When the pH was above 3.5, the degree of protonation of the carboxyl group is greatly weakened. Consequently, the adsorption capacity of Cu2+ is significantly increased.When the Cu2+ ion concentration of the solution was 120 mg/L, the adsorption capacity of the hydrogel for Cu2+ ions tended to be saturated. The maximum adsorption equilibrium could reach 452.3 mg/g within 4 min. It could expand the application of heavy metal pollution control in water systems.

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Acknowledgments. This research was financially supported by 2022 Public welfare Technology Application Research Program in Zhejiang province (Grant NO. LGG22C160003)–Construction and absorption capacity of the nanocellulosic hydrogel and the key technique in its graphitized electrode materials; the 2021 Visiting Engineer Program of Colleges of Universities in Zhejiang (NO. FG2021195)–Reduction structure design of special-shaped box and development of key barrier technology of packaging materials; University Students’ Science and Technology Innovation Program in Zhejiang (new talent plan) (No. 2022R475A006).

References 1. Norfarhana, A.S., Ilyas, R.A., Ngadi, N.: A review of nanocellulose adsorptive membrane as multifunctional wastewater treatment. Carbohyd. Polym. 291, 119563 (2022) 2. Abouzeid, R.E., Khiari, R., El-Wakil, N., Dufresne, A.: Current state and new trends in the use of cellulose nanomaterials for wastewater treatment. Biomacromol 20(2), 573–597 (2018) 3. Gholami Derami, H., et al.: A robust and scalable polydopamine/bacterial nanocellulose hybrid membrane for efficient wastewater treatment. ACS Appl. Nano Mater. 2(2), 1092–1101 (2019) 4. Huang, Y., Yang, P., Yang, F., Chang, C.: Self-supported nanoporous lysozyme/nanocellulose membranes for multifunctional wastewater purification. J. Membr. Sci. 635, 119537 (2021)

Preparation and Application of Hydrogel Materials for Interfacial Solar Vapor Generation Xinghua Du, Lu Han, Zhuoya Liu, Ruping Liu(B) , and Lanlan Hou(B) School of Printing and Packaging Engineering, Beijing Institute of Graphic Communication, Beijing, China {liuruping,lanlanhou}@bigc.edu.cn

Abstract. Mankind has great a demand for water resources in daily life. There has been an increasing focus on extracting purified water or irrigable water from seawater or sewage sources. Solar interfacial evaporation technology is considered a promising approach due to its strong operability, high solar thermal conversion efficiency, and environmentally friendly characteristics. These advantages make it as one of the best ways to improve water quality of seawater or sewage. To enhance the efficiency of solar interface evaporation, a variety of materials are employed to applied to efficient photothermal conversion and higher evaporation rates. Among these materials, hydrogel stands out as an innovative platform for achieving high evaporation efficiency. In this review, hydrogel materials are firstly introduced, including non-covalent cross-linked hydrogels and covalent crosslinked hydrogels for solar interface evaporation. Subsequently, the application of hydrogel materials in solar interface evaporation is discussed, followed by a summary of the potential future development of solar interface evaporation technology based on hydrogel materials. Keywords: Solar energy · Interface evaporation · Hydrogel · Photothermal conversion

1 Introduction Evaporation is a basic phenomenon in nature, and the evaporation process also plays an important role in the recent industrial process. Nevertheless, solar vapor generation (SVG) is energy intensive, the basic process by which solar distillation separates water and pollutants. In the past, the energy consumed by water evaporation technology was mainly from fossil fuels, which produced waste gas or liquid waste, which had a negative impact on the environment. And as the high price of fossil fuels, the development of water evaporation technology was hindered gravely. In recent years, it has become a research hotspot to search for energy sources that can replace fossil fuels and develop new materials for efficient photothermal conversion and water purification technologies derived from them. In 2014, Chen’s group proposed a new solar water desalination method, namely solar interface evaporation technology [1], which immediately attracted wide attention © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 413–417, 2024. https://doi.org/10.1007/978-981-99-9955-2_55

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around the world. Solar interface evaporation technology refers to the transfer of liquid water to the surface of solar energy absorbing materials. When photothermal conversion occurs, liquid water obtains energy, transforms phase, and generates steam, by collecting water vapor, and the high-purity water can be obtained [2]. This technology focuses solar energy on the liquid water evaporation interface, which can effectively reduce the heat loss and improve the evaporation efficiency. Solar energy provides thermal energy for interfacial evaporation can achieve environmental protection and low cost of energy, but it is worth noting that finding the ideal material or device that can achieve efficient photothermal conversion is still the key to the sustainable development of solar interface evaporation. In this paper, the cross-linking method of the hydrogel is introduced first, and after that the application of hydrogel materials in solar interface evaporation is described. Lastly, the prospect of hydrogel materials and solar interface evaporation technology is presented.

2 Cross-Linking Methods of Hydrogels Hydrogel is a cross-linked polymer network capable of retaining large amounts of water and maintaining a three-dimensional hierarchy. The cross-linking of hydrogel networks can be divided into non-covalent bonds (physical bonds), and covalent bonds (chemical bonds) (Table 1) [3]. Non-covalent cross-linking is usually based on molecular interactions such as ionic/electrostatic interactions, hydrophobic interactions, hydrogen bonding, crystallization, metal coordination, and π-π stacking. Compared to non-covalently cross-linked hydrogels, covalently cross-linked hydrogels are generally more mechanically stable and permanent due to the strong covalent bonds formed between polymer chains. Almost all covalent cross-linking methods require cross-linking agent, and some polymerizations also require initiating chemicals. According to their different mechanisms, chemical crosslinking methods include free radical polymerization, aldehyde mediated, click chemistry, and condensation reactions. Table 1. Cross-linking methods of hydrogels cross-linking mechanisms types

methods

example

Noncovalent ionic/electrostatic self-cross-linking divalent cations + alginate (physical) interaction by blending

References [4]

Hydrophobic interaction

thermal induction based on LSCT/UCST

poly(Nisopropylacrylamide) [5]

crystallization

freeze − thawing, freeze drying

poly(vinyl alcohol)

[6]

(continued)

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Table 1. (continued) cross-linking mechanisms types

Covalent (chemical)

Covalent (chemical)

methods

example

References

hydrogen bonding

copolymerization PEG-ureidopyrimidinone (UPy)

[7]

metal coordination

self-cross-linking Zn2+ with organic ligand, by blending 2,2’:6’,2 -terpyridine (tpy)

[8]

π − π stacking

thermal treatment

PEDOT hydrogels

[9]

Radical polymerization

photoirradiation or initiators

PINPAM + ammonium persulfate

[10]

aldehyde-mediate self-cross-linking PVA + glutaraldehyde cross-linking by blending

[11]

self-cross-linking PAA + carboxymethyl by blending cellulose

[12]

Condensation reaction click chemistry

hyaluronic acid hydrogels

[13]

3 Development and Application of Hydrogel Materials in Solar Interface Evaporation Lei et al. introduced activated carbon (AC) particles as a solar absorber to prepare a polyamphoteric hydrogel (PZHs) evaporator. This PZH-based evaporator has the advantages of simple preparation, controllable price and high reuse rate [14]. On this basis, PDMAPS hydrogel was immersed in LiCl solution, and then salt was added to the hydrogel to prepare PDM APS-LiCl hydrogel, which can be used in Atmospheric water harvesting (AWH) and has also achieved favorable results [15]. Li et al. prepared a multi-layer hydrogel solar evaporator (ML-SVG) based on in situ radical polymerization manner. The design of this multi-layer structure significantly improves the photothermal conversion efficiency of the evaporator, greatly reduces the heat loss, and has excellent performance of water transport, which can effectively improve the evaporation efficiency. At 2 kW·m−2 light intensity, the evaporation rate of water is 2.2 kg·m−2 ·h−1 , and the evaporator can also efficiently purify sewage containing metal ions or acid and alkaline sewage [16]. Zhao et al. prepared a layered nanostructured gel (HNG) based on PVA and polypyrrole (PPy) by cyclic freeze-thaw, which includes internal interstitial spaces, micron channels and molecular grids, as shown in Fig. 1a and 1b. Under natural conditions, HNG can produce 18–23 L·m−2 fresh water per day, which can be used in the fields of seawater purification and emergency rescue [11], as shown in Fig. 1c. Zhou et al. constructed an absorbent hydrogel h-LAH composed of PVA and chitosan by in-situ collaborative method, as shown in Fig. 1d. h-LAH increased the solar steam generation rate to a record 3.6 kg·m−2 ·h−1 [17].

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Fig. 1. Schematic diagram of hydrogel composition and the evaporator structure: (a) Structure diagram of HNG (b) Schematic diagram of the solar steam generation system (c) Outdoor solar water purification in natural sunlight. (d) SVG schematic diagram based on h-LAH hydrogel

4 Conclusion and Prospect Hydrogel materials have been widely studied in the field of solar interface evaporation, which can continuously provide water to the evaporation interface.Their controllable mechanical properties make it possible to adjust the viscoelasticity and swelling property according to demand. However, it is particularly important to implement accurately regulation of hydrogel properties because of the high photothermal conversion efficiency required for evaporation. How to improve its hydrophilicity and regulate appropriate mechanical properties have become a problem that developers need to consider. Then, the joint assembly of hydrogels and other materials is becoming a new development trend, using the characteristics of other materials to promote the performance of hydrogels, can improve its hydrophilic and mechanical properties. Moreover, the advance designing on devices to carry hydrogels and achieve efficient interfacial evaporation become popular form. In the future, there will be more physical-chemical outstanding and robust hydrogels, that achieve high efficient and stable water purification with economic and green environmental protection. Acknowledgments. This work was supported by the National Natural Science Foundation of China (No. 62371051 and No. 61971049), the Projects of International Cooperation and Exchanges NSFC (No. 62211530446), and the Discipline construction of material science and engineering (No. 21090123007).

References 1. Ghasemi, H., Ni, G., et al.: Solar steam generation by heat localization. Nat. Commun. 5, 4449 (2014) 2. Lewis, N.S.: Research opportunities to advance solar energy utilization. Science 351, aad1920 (2016) 3. Guo, Y., Bae, J., et al.: Hydrogels and hydrogel-derived materials for energy and water sustainability. Chem. Rev. 120, 7642–7707 (2020)

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4. Gacesa, P.: Alginates. Carbohydr. Polym. 8, 161–182 (1988) 5. Fu, W., Zhao, B.: Thermoreversible physically crosslinked hydrogels from UCST-type thermosensitive aba linear triblock copolymers. Polym. Chem. 7, 6980–6991 (2016) 6. Abitbol, T., Johnstone, T., et al.: Reinforcement with cellulose nanocrystals of poly(Vinyl Alcohol) hydrogels prepared by cyclic freezing and thawing. Soft Matter 7, 2373–2379 (2011) 7. Hofmeier, H., Hoogenboom, R., et al.: High molecular weight supramolecular polymers containing both terpyridine metal complexes and ureidopyrimidinone quadruple hydrogenbonding units in the main chain. J. Am. Chem. Soc. 127, 2913–2921 (2005) 8. Shi, Y., Wang, M., et al.: A conductive self-healing hybrid gel enabled by metal−ligand supramolecule and nanostructured conductive polymer. Nano Lett. 15, 6276–6281 (2015) 9. Yao, B., Wang, H., et al.: Ultrahigh-conductivity polymer hydrogels with arbitrary structures. Adv. Mater. 29, 1700974 (2017) 10. Ma, C., Shi, Y., et al.: Thermally responsive hydrogel blends: a general drug carrier model for controlled drug release. Angew. Chem. Int. Ed. 54, 7376–7380 (2015) 11. Zhao, F., Zhou, X., et al.: Highly efficient solar vapour generation via hierarchically nanostructured gels. Nat. Nanotechnol. 13, 489–495 (2018) 12. Koo, B., Kim, H., et al.: A highly cross-linked polymeric binder for high-performance silicon negative electrodes in lithium ion batteries. Angew. Chem. Int. Ed. 51, 8762–8767 (2012) 13. Nimmo, C.M., Owen, S.C., Shoichet, M.S.: Diels−Alder click cross-linked hyaluronic acid hydrogels for tissue engineering. Biomacromol 12, 824–830 (2011) 14. Lei, C., Guan, W., et al.: Polyzwitterionic hydrogels for highly efficient high salinity solar desalination. Angew. Chem. Int. Ed. 61, e202208487 (2022) 15. Lei, C., Guo, Y., et al.: Polyzwitterionic hydrogels for efficient atmospheric water harvesting. Angew. Chem. Int. Ed. 61, e202200271 (2022) 16. Li, T., Meng, W., et al.: Preparation and performance of multilayer polyacrylamide hydrogel solar evaporator. Mater-Rep. (2023) 17. Zhou, X., et al.: Architecting highly hydratable polymer networks to tune the water state for solar water purification. Sci. Adv. 5, eaaw5484 (2019)

Fabrication of Flexible Devices by Inkjet Printing Lu Han, Xinghua Du, Qinghua Duan, Lanlan Hou(B) , and Ruping Liu(B) School of Printing and Packaging Engineering, Beijing Institute of Graphic Communication, Beijing, China {lanlanhou,liuruping}@bigc.edu.cn Abstract. Currently, flexible devices have a wide range of applications such as health managements, drug deliveries, and electronic skins. The inkjet printing is considered the most promising technology for manufacturing flexible devices due to its high resolution, large scale, and low cost. Here, we give a comprehensive review of the fabrication of flexible devices by inkjet printing. First, we introduce the different types of inkjet printing, including continuous inkjet printing and on-demand inkjet printing. In addition, we describe flexible substrates and nanometallic inks for preparation of flexible devices. Lastly, the perspectives for future development of flexible devices are proposed. Keywords: Inkjet printing · Flexible device · Flexible substrate

1 Introduction In recent years, the application of flexible devices has been increasing, such as sensors [1], memristors [2], capacitors [3], diodes [4], circuit boards and solar cells [5]. Especially with the rapid development of flexible wearable devices, there is an urgent need for a feasible printing method that can print high-quality flexible devices. However, the traditional plate-printing and evaporation technologies have been unable to meet the high quality and efficiency required for the production of flexible devices due to issues of high cost, complex processes, and poor-quality control. Compared to traditional methods, inkjet printing requires no contact, no mask, and low cost [6]. The inkjet printing shows great potential in the manufacture of flexible devices: (a) No plate making, the digital process is simple and fast. (b) Non-contact deposition, substrate and pattern layout flexible. (c) High resolution, meets the accuracy of device. This paper summarizes the recent progress of inkjet printing in fabrication of flexible devices, including the design principle of different types of inkjet printing technology, the common flexible substrates, and nano-metallic inks. It provides a reference for the preparation of flexible devices.

2 Inkjet Printing Inkjet printing is contactless, pressure-free and plateless. Because of the high precision of printing and easy control of ink raw materials, it is very suitable for manufacturing flexible devices. Different inkjet printing technologies have evolved, including continuous inkjet printing and on-demand inkjet printing (Fig. 1) [7]. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 418–423, 2024. https://doi.org/10.1007/978-981-99-9955-2_56

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Fig. 1. Continuous inkjet printing (a) and on-demand inkjet printing (b) with hot bubble (left) and piezoelectric (right) printhead

2.1 Continuous Inkjet Printing Continuous inkjet printing refers to the continuous injection of ink droplets through a pressure chamber equipped with ink. Under the action of ultrasonic driving signal generated by the piezoelectric crystal, the ink flow is decomposed into continuous drops of ink by high-frequency oscillation. A charging electric field controlled by a graphic output signal is provided at the nozzle. The ink droplet is selectively charged when passing through the nozzle [8]. In binary deflection inkjet printing. The droplets participating in recording are not affected by the deflecting magnetic field and keep straight. But the trajectory of charged ink droplet in multi-value deflection inkjet printing is transformed under the action of electric field to reach substrate. Uncharged ink droplets remain in a straight line until they are intercepted by an interceptor and enter the recovery system. Unlike binary deflection, the value of ink drop deflection in multi-value inkjet printing can be changed. 2.2 On-Demand Inkjet Printing In on-demand inkjet printing, ink droplets are sprayed only for a specified period of time [9]. It has a small inkjet speed, around 30 kHz [10]. But the droplet diameter can reach 10–500 µm. On-demand inkjet printing can be divided into hot bubble inkjet printing and piezoelectric inkjet printing. Hot Bubble Inkjet Printing. The ink chamber of the hot bubble inkjet printing system is equipped with a film heater and covered with a layer of ink. As the printing system works, the film heater causes the ink to form steam bubbles in an extremely short time. The expanding bubbles push out ink and form ink droplets [11]. Then the film heater cools, the ink fills the nozzle by capillary action. Injection speed is greatly limited because the ink chamber must be refilled with ink before the next drop can be sprayed out. The initial driving pressure is close to the saturated vapor pressure of the liquid at its superheating limit. So Clogged nozzles are a major problem [12]. Piezoelectric Inkjet Printing. Piezoelectric inkjet printing is similar to hot bubble inkjet printing, the difference is that the formation method of ink droplets is different.

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Piezoelectric inkjet printing relies on the mechanical action of piezoelectric films to produce pulses [13]. When an electric current is passed through the piezoelectric actuator, it creates a tiny deformation. Therefore, the volume of the ink chamber is reduced, and the ink is extruded from the nozzle. By changing the driving voltage of the piezoelectric actuator, the speed and volume of the jet droplet can be controlled [14].

3 Flexible Substrates of Flexible Devices Compared with conventional devices, flexible devices can be bent, folded and even transformed into any shape. The substrate of a flexible device is the basis for its flexibility. It can be made from various materials such as paper, conductive glass, and polymer. 3.1 Paper The paper substrate enables the device to work normally under extreme deformation conditions such as folding, and is easy to recycle, without causing environmental pollution and waste of resources [15]. For its porosity, functional materials are coated on the surface to improve its printability. For example, paper coated with a layer of resin is suitable for inkjet printing. The resin layer helps the paper substrate capture ink particles and absorb excess liquid, resulting in a narrow resolution substrate surface [16]. But the hygroscopicity of paper substrate is worth considering. If the moisture is absorbed by the paper, the device is prone to failure. And during the sintering process, the paper made of cellulose will begin to decompose at a temperature of 100 °C. 3.2 Conductive Glass In contrast to a soft paper substrate, conductive glass is a rigid substrate. Conductive glass is divided into volume conductive glass and surface conductive layer glass. The composition of volume conductive glass usually contains basic oxide, silicon oxide and titanium oxide. Surface conductive layer glass refers to the glass surface covered with a layer of conductive film. For example, a film of indium tin oxide (ITO) is plated on a sodium-calcium or boron-silicate substrate glass [17]. It has good transparent conductivity, high transmittance and low resistivity in the visible spectrum, and is widely used in display devices, solar cells and other photoelectric devices. The glass substrate gives the device good electrical and optical properties. With the rapid development of flexible devices, it has a wide prospect. 3.3 Polymer Polyimide material has comprehensive properties, and its main chain contains the imide ring and nitrogen five-membered heterocyclic ring (Table 1). Among them, PEI has excellent high temperature resistance, corrosion resistance and electrical properties, is widely used in the manufacture of flexible device substrate [18]. PI contains two acyl imide monomers bonded to nitrogen. It is known for its high thermal stability, which also

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has excellent dielectric properties and an inherently low coefficient of thermal expansion [19]. In many industrial applications, PI is used to replace glass, metal and even steel. PAI is a polymer obtained by modifying PI. The heat-resistant aromatic heterimide groups and the flexible amide groups are arranged in regular alternations [20]. Polymers provide excellent mechanical properties, heat resistance and creep resistance for flexible devices. Table 1. Properties of polyimide materials species

structure

PI

PAI

PEI

>250

270 300

>215

3

4

>500

>100

>450

>175

3.9

>518

>110

3.2

4 Nano-metallic Inks At present, conductive inks such as graphene [21], carbon nanotubes [22], nano-metallic inks [23], and conductive polymers are developed [24]. Among them, Nano-metallic inks are most widely used in the preparation of flexible devices, because they have better stability and a high load of 4.0% wt. That means more metal can be deposited each time through inkjet printing. Au, Ag, Cu and other metal nanoparticles can be used to prepare conductive inks. They can be synthesized by physical milling, but the size is not uniform. Reduced metal salts are more reliable in controlling particle size. Compared with Au, Ag nanoparticles have lower resistivity and lower production cost, and have become a popular material for preparing conductive layers of flexible devices. Although the cost of copper is low and the conductivity is high, the high oxide formation rate of copper NPs requires the protection of the precious metal antioxidant shell. In order to improve the performance of ink injection and stability. Dispersant, surfactant, thickener and stabilizer are often added to nano-metallic inks according to the actual demand. The surface design and modification have endowed the nano metallic inks more special properties for greater applications in flexible devices.

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5 Conclusions and Prospects In recent years, inkjet printing has made breakthroughs in convenience, high resolution, mass production, and low cost. Inkjet printing is becoming a common tool for manufacturing flexible devices. However, it needs to overcome new problems to meet the new requirements of flexible devices: (a) Improve the inkjet printing equipment to realize the control of a finer volume of ink droplets. (b) Optimize the substrate materials to improve compatibility with ink. (c) Improve the ink formula to enhance printing quality. Embracing advancements in equipment, substrate materials, and ink formulation will unlock new possibilities, propelling the field forward and empowering researchers and manufacturers to create increasingly sophisticated and high-performance flexible devices. Acknowledgement. This work was supported by the National Natural Science Foundation of China (No. 62371051, No. 61971049), the Projects of International Cooperation and Exchanges NSFC (No. 62211530446), and the Discipline construction of material science and engineering (No. 21090123007).

References 1. Han, S.-T., et al.: An overview of the development of flexible sensors. Adv. Mater. 29(33), 1700375 (2017) 2. Zhang, H., et al.: Research progress of biomimetic memristor flexible synapse. Coatings 12(1), 21 (2021) 3. Zhao, W., Jiang, M., Wang, W., Liu, S., Huang, W., Zhao, Q.: Flexible transparent supercapacitors: materials and devices. Adv. Func. Mater.Func. Mater. 31(11), 2009136 (2020) 4. Lian, C., et al.: Flexible organic light-emitting diodes for antimicrobial photodynamic therapy. npj Flex. Electron. 3(1), 18 (2019) 5. Cheng, Y.-B., Pascoe, A., Huang, F., Peng, Y.: Print flexible solar cells. Nature 539(7630), 488–489 (2016) 6. Zhang, F., et al.: Reactive material jetting of polyimide insulators for complex circuit board design. Addit. Manuf.. Manuf. 25, 477–484 (2019) 7. Huang, T.-T., Wu, W.: Scalable nanomanufacturing of inkjet-printed wearable energy storage devices. J. Mater. Chem. A 7(41), 23280–23300 (2019) 8. Shah, M.A., Lee, D.-G., Lee, B.-Y., Hur, S.: Classifications and applications of inkjet printing technology: a review. IEEE Access 9, 140079–140102 (2021) 9. Basiricò, L., Cosseddu, P., Fraboni, B., Bonfiglio, A.: Inkjet printing of transparent, flexible, organic transistors. Thin Solid Films 520(4), 1291–1294 (2011) 10. Peng, X., et al.: Simulation of a hemispherical chamber for thermal inkjet printing. Micromachines 13(11), 1843 (2022) 11. Peng, X., et al.: Design of h-shape chamber in thermal bubble printer. Micromachines 13(2), 194 (2022) 12. Kim, T., et al.: Inkjet-printed stretchable single-walled carbon nanotube electrodes with excellent mechanical properties. Appl. Phys. Lett. 104(11), 113103 (2014) 13. Ko, S.H., Chung, J., Pan, H., Grigoropoulos, C.P., Poulikakos, D.: Fabrication of multilayer passive and active electric components on polymer using inkjet printing and low temperature laser processing. Sens. Actuators A 134(1), 161–168 (2007)

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14. Beedasy, V., Smith, P.J.: Printed electronics as prepared by inkjet printing. Materials 13(3), 704 (2020) 15. Rida, A., Yang, L., Vyas, R., Tentzeris, M.M.: Conductive inkjet-printed antennas on flexible low-cost paper-based substrates for RFID and WSN applications. IEEE Antennas Propag. Mag.Propag. Mag. 51(3), 13–23 (2009) 16. Ozcan, A., Tozluoglu, A., Kandirmaz, E.A., Tutus, A., Fidan, H.: Printability of variative nanocellulose derived papers. Cellulose 28(8), 5019–5031 (2021) 17. Rudzik, T.J., Gerhardt, R.A.: Effect of spark plasma sintering current and voltage on the microstructure and electrical properties of borosilicate glass-indium tin oxide composites. Adv. Eng. Mater. 22(5), 1901431 (2020) 18. Lei, W., et al.: Fabrication of electrospun polyetherimide/polyaniline self-supporting microfiber membranes as electrodes for flexible supercapacitors via in-situ polymerization. Colloids Surf. A 651, 129796 (2022) 19. Butnaru, I., Serbezeanu, D., Bruma, M., Sava, I., Gaan, S., Fortunato, G.: Physical and thermal properties of poly(ethylene terephthalate) fabric coated with electrospun polyimide fibers. High Perform. Polym.Polym. 27(5), 616–624 (2015) 20. Mallakpour, S., Zadehnazari, A.: Synthesis and characterization of novel heat stable and processable optically active poly(amide–imide) nanostructures bearing hydroxyl pendant group in an ionic green medium. J. Polym. Environ.Polym. Environ. 21, 132–140 (2012) 21. Deng, D., Feng, S., Shi, M., Huang, C.: In situ preparation of silver nanoparticles decorated graphene conductive ink for inkjet printing. J. Mater. Sci. Mater. Electron. 28(20), 15411– 15417 (2017) 22. Tortorich, R., Choi, J.-W.: Inkjet printing of carbon nanotubes. Nanomaterials 3(3), 453–468 (2013) 23. Raut, N.C., Al-Shamery, K.: Inkjet printing metals on flexible materials for plastic and paper electronics. J. Mater. Chem. C 6(7), 1618–1641 (2018) 24. Kraft, U., Molina-Lopez, F., Son, D., Bao, Z., Murmann, B.: Ink Development and Printing of Conducting Polymers for Intrinsically Stretchable Interconnects and Circuits. Adv. Electron. Mater. 6(1), 1900681 (2019)

Research Progress of MXenes Based Gas Sensors Chen Liu, Yabo Fu, Kexin Xue, Jiazi Shi(B) , Meichen Lin, Yingjie Jin, Gaimei Zhang, Dongli Li, Ruijuan Liao, Xinlin Zhang, Dongdong Wang, and Hui Liu Beijing Key Laboratory of Printing & Packaging Materials and Technology, Beijing Institute of Graphic Communication, Beijing 102600, China [email protected]

Abstract. MXenes not only have the same conductivity as metals, but also have good mechanical and hydrophilic properties. Therefore, MXenes have special appeal and competitiveness in fields such as energy storage conversion, catalysis, sensors, electromagnetic interference (EMI) shielding, etc. Especially, due to its layered structure, MXenes have a large specific surface area for gas molecules to adsorb. However, MXenes have poor chemical stability, so it is particularly important to study their combination with other materials for gas detection. This article reviews the research progress of MXenes as sensitive materials for gas sensors, proving that MXenes have been potential candidates for gas sensing materials. Keywords: MXenes · Application · Two-Dimensional materials · Gas sensors

1 Introduction The increase in population, the rapid development of the industrial sector, and the increase in car usage and exhaust emissions are all causing environmental degradation. NOx , COx , SOx , and particulate matter are some of the gases that cause pollution. In this case, gas sensors play a crucial role in detecting harmful gases [1]. In recent years, flexible conductive gas sensors have been widely used in daily life to detect harmful gases [2]. Recently, a new family of 2-D materials was proposed-MXenes, of which were synthesized from their parent M n+1 AX n phase by a simple chemical etching method [3]. MAX phase corresponds to the general formula M n+1 AX n (n = 1, 2, 3), where M represents the early d-block transition metal, a represents the major group SP elements (especially groups 13 and 14), and X is the C or N atom [4]. MXene is synthesized by selectively etching layer A from MAX phase at room temperature. The final MXene is a loose stacked exfoliated graphite layered structure [5], and polymerized titanium carbide (Ti3 C2 Tx ) is a typical proven MXene [6]. As a member of the 2D nanomaterial family, MXenes have various excellent chemical and physical properties [7]. In particular, lots of members of MXenes family have been found and MXenes family has three atomic structures, ranging from M2 X, M3 X2 and M4 X3 , which can provide adjustability and opportunities to discover and mold materials as needed [8]. Because MXenes have such a lamellar structure, which expands the © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024 H. Song et al. (Eds.): CACPP 2023, LNEE 1144, pp. 424–430, 2024. https://doi.org/10.1007/978-981-99-9955-2_57

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specific surface area and increases the adsorption sites of gas molecules, this structure is expected to achieve additional sensitization. Therefore, Titanium carbide MXenes based composites have been studied as potential materials for gas detection [9]. However, MXenes have poor chemical stability and are prone to oxidation, resulting in the loss of excellent conductivity. However, it is worth expecting that due to the large gap between layers, other nanomaterials can easily enter and form nanocomposites with them [10]. Therefore, it is possible to combine it with other materials to develop more sensitive and stable gas sensors.

2 Gas Sensing and Detection of MXenes Recent studies have found that MXenes can not only be used as a gas sensing material, but also can detect very trace gases, and the response noise to gases is very low. Meanwhile, as a gas sensitive material, MXenes have different response behavior and gas sensing mechanism from ordinary semiconductor gas sensitive materials [11]. For example, the reactivity and selectivity of four MXenes (i.e. M2 C (M = Ti, V, Nb, Mo)) and their oxygen functionalized forms (i.e. O-MXenes or M2 CO2 ) to gas molecules were studied by using the density functional theory (DFT) calculations based on plane waves by junkaw et al. [12] Mo2 CO2 and V2 CO2 had good selectivity for NO, while Nb2 CO2 and Ti2 CO2 had good selectivity for NH3 . NO and NH3 tended to bind to oxygen and metals, respectively. H2 , N2 , CO, CO2 , NO2 , SO2 were weakly combined with most O-MXenes. 2.1 MXenes Detects VOCs Gas The basic principle of gas sensing material is that the resistance of the material changes due to the adsorption of gas. MXene provides the flexibility [13] to terminate its surface with functional groups containing oxygen (O), hydroxyl (OH) and fluorine (F). With this feature, MXene can detect VOCs at room temperature. For example, The MXene Lee et al. [14] prepared was obtained by etching Ti3 AlC2 with HCl/LiF (Fig. 1). The Ti3 C2 Tx sensor has the highest and lowest responses to ammonia and acetone, respectively. And Yang et al. [15] reported a VOCs sensor based on MXene/Polyvinyl alcohol (PVA)/Palmitoylethanolamide (PEI) nanocomposites. The results showed that the sensor has high sensitivity, wide detection range, low LOD, fast response and recovery (both