Sensitive Wearable Strain Sensor Based on a Self-Doped Conductive Hydrogel
Hongyu Ji, Haochen He, Jiangang Sun, Wen Lu, Hengfeng Yu, Junda Zhu, Yixiao Liu, Shimeng Chen, Hongliang Cao
Abstract
Conductive hydrogels have been widely applied to develop flexible and wearable sensors. Classic conductive polymers such as poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) exhibit high conductivity and biocompatibility, but their intrinsic insolubility may affect the establishment of conductive pathways, thereby further impeding the enhancement of both electrical and mechanical properties. In this study, a self-doped highly conductive poly(3,4-ethylenedioxythiophene) sulfonate (PEDOT-S) solution was obtained by photopolymerization, avoiding the introduction of iron ions. Following this, we developed a double network (DN) hydrogel system from poly(vinyl alcohol) and polyacrylamide via a freezing–thawing approach, combining with PEDOT-S as conductive agent. The hydrogel exhibited robust mechanical strength, adhesive capability, and remarkable conductive sensitivity. As a strain sensor, the conductive hydrogel can be used to detect body motion and vocal cord vibrations, providing promising potential for application in flexible and wearable devices.