Sensitive Wearable\nStrain Sensor Based on a Self-Doped\nConductive Hydrogel

Abstract

Conductive hydrogels have been widely applied to develop\nflexible\nand wearable sensors. Classic conductive polymers such as poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)\nexhibit high conductivity and biocompatibility, but their intrinsic\ninsolubility may affect the establishment of conductive pathways,\nthereby further impeding the enhancement of both electrical and mechanical\nproperties. In this study, a self-doped highly conductive poly(3,4-ethylenedioxythiophene)\nsulfonate (PEDOT-S) solution was obtained by photopolymerization,\navoiding the introduction of iron ions. Following this, we developed\na double network (DN) hydrogel system from poly(vinyl alcohol) and\npolyacrylamide via a freezing–thawing approach, combining with\nPEDOT-S as conductive agent. The hydrogel exhibited robust mechanical\nstrength, adhesive capability, and remarkable conductive sensitivity.\nAs a strain sensor, the conductive hydrogel can be used to detect\nbody motion and vocal cord vibrations, providing promising potential\nfor application in flexible and wearable devices.