Synthesis of a PNIPAM-Based Composite Hydrogel and Its Multipurpose Applications in Piezoresistive and Temperature Sensing

Herein, a poly(N-isopropylacrylamide)-based conductive composite hydrogel system coenhanced by clay and polydopamine-modified MXene was synthesized to achieve strain and temperature sensibility simultaneously. The noncovalently cross-linked network via MXene, clay, and polymer chains endowed the synthesized hydrogel with excellent mechanical properties (tensile strength at a break of 117 kPa and elongation at a break of 1723%). This hydrogel also exhibits strong adhesion and good electrical conductivity (0.13 S/m). Regarding the sensing properties, its temperature sensitivity is 2.749 °C−1, while its strain detection limit is as low as 0.05%. Based on the unique characteristics of the prepared hydrogel, the as-assembled sensor can detect stress and temperature simultaneously, exhibiting great application potential in human physiological monitoring.