文献类型：期刊文献

英文题名：Drying-enhanced polyvinyl alcohol-polyacrylic acid double-network hydrogel and its application in flexible strain sensors

作者：Liu, Jiawei;Liu, Xing;Chen, Jiao;Wang, Hanhan;Han, Xia[1];Liu, Honglai

机构：[1]East China Univ Sci & Technol, Key Lab Adv Mat, Shanghai 200237, Peoples R China; East China Univ Sci & Technol, Sch Chem & Mol Engn, Shanghai 200237, Peoples R China

年份：2022

卷号：264

外文期刊名：CHEMICAL ENGINEERING SCIENCE

收录：;EI(收录号：20224212898753);WOS:【SCI-EXPANDED(收录号:WOS:000890856800002)】；

基金：The authors gratefully acknowledge the financial support from the National Natural Science Foundation of China (No. 21878075 and 22178097).

语种：英文

外文关键词："freezing-drying-swelling" cycle; Strain sensor; PVA-PAA; Double-network hydrogel

摘要：Polyvinyl alcohol (PVA) based hydrogels, are generally prepared by freeze-thaw cycling methods. However, water loss and shrinkage of the gel over time should be prevented during the freeze-thaw cycles. Herein, a polyvinyl alcohol-polyacrylic acid (PVA-PAA) double-network hydrogel was fabricated through the strategy of ''freezing-drying-swelling" (FDS) cycle, where the moisture retention was unnecessary. By a freezing-drying treatment, the formation of PVA crystalline domains and hydrogen bonds in freezing step was further improved by the drying treatment, and subsequently enhanced the mechanical properties of the hydrogel. The FDS hydrogel with the cross-linker content of 0.1% and one FDS cycle (FDS-0.1-1) could reach the ultimate tensile stress as high as 1.1 MPa with high stretchability of 648% strain. Thanks to the combination of PAA and conductive ions, the FDS-0.1-1 hydrogel strain sensor possessed excellent conductivity with a wide strain monitoring range of 0-250%, high sensitivity with a gauge factor (GF) up to 3.985, a fast response (75 ms) and excellent long-term stability without any decay for 5000 cycles of continuous loading-unloading between 0 and 100% strain. Besides, the FDS hydrogel strain sensor can be used for real-time monitoring various movements of the human body, including large movements (finger, wrists, elbows, and back of the neck) and subtle motions (smile and swallow). (C) 2022 Elsevier Ltd. All rights reserved.