LiCl-PAM/SA-Ca^(2+)双网络水凝胶应变传感器的制备与性能

Preparation of LiCl-PAM/SA-Ca^(2+) double network hydrogel and its application in strain sensor

近几年,导电水凝胶应变传感器将不可见的机械刺激转化为可见的电信号的能力越来越受到科研人员的关注.同时,其优异的透明性和导电性也为成为柔性电子产品奠定了基础.然而,由于水凝胶内部存在大量水分,环境适应性差(如低温和长期储存)限制了实际应用.因此,本工作通过使用LiCl作为海藻酸钠分子链超分子组装的触发器并引入甘油作为冷冻保护剂,开发了一种新型离子导电LiCl/PAM/SA-Ca^(2+)水凝胶.结果表明:离子导电水凝胶不仅具有较高的断裂应变(1920%)和与人体皮肤相似的模量(80 kPa),而且具有优异的机械强度(375 kPa)、出色的韧性(4.8 MJ·m^(-3))和高透明度;此外,氯化锂和甘油也赋予其防冻和保湿功能;进一步研究表明:作为柔性应变传感器,离子水凝胶在300%至750%的应变范围内具有高灵敏度(GF=2)和宽检测应变窗口(2.5%~500%).同时该应变传感器也表现出优异的抗疲劳性(100%应变下200次循环)和低温(-25℃)下的传感灵敏度.这种独特的性能为可穿戴设备在复杂环境中的应用提供了更多可能.

In recent years,conductive hydrogels have increasingly attracted attention from scientific researchers own to the ability to transform invisible mechanical stimuli into visible electrical signals.At the same time,its excellent transparency and conductivity also laid the foundation to become flexible electronics.However,poor environmental adaptability(such as low temperature and last-long storage)limited practical applications due to existence of large amount of water inside hydrogel.Herein,in this work,a novel ionic conductive LiCl/PAM/SA-Ca^(2+)hydrogel was developed by the use of LiCl as triggers in supramolecular assembly between SA chain and introducing glycerol as cryoprotectant.The results showed that the ionic conductive hydrogel not only possessed high fracture strain(1920%)and the similar modulus with human skin(80 kPa),but also robust mechanical strength(375 kPa),outstanding toughness(4.8 MJ·m^(-3))and high transparency.Furthermore,LiCl and glycerol imparted anti-freezing and moisture-retention to it.Further research showed that the ionic hydrogel was confirmed as strain sensors with high sensitivity(GF=2)at strain range from 300%to 750%and wide detection strain window(2.5%-500%).Similarly,the strain sensor exhibited excellent fatigue resistance(200 cycles at 100%strain)and sensing sensitivity at low-temperature(-25℃).The unique ability can provide more possibilities for the application of wearable devices in complex environments.