Multi-synergistic strategy for dual-sensing conductive hydrogels capable of simultaneous strain and temperature monitoring

Abstract

Conductive hydrogels have exhibited extensive applications in flexible electronics owing to their exceptional flexibility, tailorable mechanical properties, and comprehensive multifunctional features. However, a prevalent limitation in existing research is that the design of many multifunctional hydrogels often relies solely on the combination of different functional materials, without adequate consideration for constructing synergistically interacting relationships among their components. Through the multiple synergistic effects among phytic acid, boric acid, Iron ions (Fe³⁺), and with the polymer chains, multifunctional integration was achieved. The as-prepared hydrogel exhibites a distinctive three-dimensional network architecture that is inherently associated with both its mechanical and electrical properties. The multifunctional hydrogel shows remarkable integrated performance, with high electrical conductivity (∼9.72 S·m⁻¹), superior water retention, high extensibility (∼1337%), and favorable adhesive properties. When employed as a strain sensor, it exhibits a high gauge factor (GF = 4.93), a fast response time, and a broad linear working range (0%–1300%). When employed as a temperature sensor, the hydrogel exhibited a temperature coefficient of resistance of −1.26%·°C⁻¹. Capitalizing on this thermo-responsive characteristic, a high-fever warning system was successfully constructed that triggers an audible alarm once the body temperature exceeds the preset threshold. Benefiting from these exceptional performance features, the hydrogel exhibits substantial application potential in wearable devices, human motion monitoring, and human body temperature measurement.