Fabrication of high-toughness PEDOT:PSS-based conductive hydrogel strain/temperature sensors

Abstract

Conductive hydrogels have important potential applications in the field of flexible sensors; however, most hydrogel sensors usually possess only a single functional property. In this study, a multifunctional hydrogel with both high mechanical toughness and temperature-responsive properties was successfully constructed by introducing PEDOT:PSS into polyvinyl alcohol/sodium alginate (PVA/SA) hydrogel networks. In this study, a multifunctional conductive hydrogel with both high mechanical toughness and temperature-responsive properties was constructed by modifying PEDOT:PSS with dilute sulfuric acid and introducing it into the PVA/SA hydrogel network. The modified PEDOT:PSS significantly enhanced the electrical conductivity (48.69 mS m⁻¹), mechanical properties (fracture strength of 45.38 kPa, ductility of 209.13%) and fatigue resistance of the hydrogel through electrostatic interaction and hydrogen-bonded cross-linking. The hydrogel has excellent strain sensing ability to detect small deformation (2.5%), which is suitable for monitoring physiological signals such as joint motion, vocal cord vibration and breathing; it also has temperature response characteristics (−2.43 Ω K⁻¹, 7.91 mV K⁻¹), which can be used for body temperature monitoring. The introduction of PEDOT:PSS realizes the multifunctional sensing of hydrogel, which provides a new idea for wearable biosensors with new ideas.