Highly Stretchable, Repeatable and Easily Prepared Ionogel Based on Polyvinyl Chloride for Wearable Sensor

Abstract

Conventional hydrogels are prone to water loss and instability, and non-hydrogel materials also have the fatal drawbacks of poor stability and low repeatability. Therefore, a flexible sensing material is needed to meet the requirements of high elasticity, good stability, and high repeatability. In this work, polyvinyl chloride (PVC) ionogel with PVC gel as elastomer matrix and 1-ethyl-3-methylimidazolium thiocyanate ([EMIM] [SCN]) as dielectric was prepared by a simple physical blending method, which exhibits good physicochemical stability without any phase change in the range of -30 °C ~ 127 °C. PVC ionogel has a maximum tensile strain of 424 %, the shape and dimensions of which remain virtually unchanged in air for 60 days. The PVC ionogel (DBA 7, IL 3 %) showed the best performance, which exhibited the best linearity with a relative error of only 0.96 %, sensitivity of 1.90, modulus of 17.71 kPa, reaction rate of 161 ms, and can operate continuously and stably for 35,000 cycles. This excellent performance enables PVC ionogel to accurately and comprehensively detect the limb information of human movement. This work provides a new idea for the design of flexible sensing materials with variable parameters, and a new solution for the development of wearable devices, sports risk monitoring, boxing action optimization and so on.

Keywords: Polyvinylchloride ionogel, Flexible sensor, Motion monitoring, Wearable devices