Extreme Temperature-Tolerant Conductive Gel with Antibacterial Activity for Flexible Dual-Response Sensors

Flexible sensors based on conductive hydrogel show great potential in electronic skin and human-machine interface. However, pure water in hydrogel inevitably freezes or rapidly evaporates under extreme temperatures, leading to inadequate fulfillment of sensor performances. Herein, a well-designed strategy is reported for fabricating extreme temperature-tolerant gel-based sensors. By immersing a gelatin/polyacrylamide (PAAm)-clay composite (GC) hydrogel into a ZnCl₂/water/glycerol system, a phase-transition-tunable gel (PTTGC gel) is obtained with outstanding antifreezing (-82 °C) and long-lasting moisture (70 °C, more than 40 days) properties. Meanwhile, the gel also presents good antibacterial activity and biocompatibility attributing to Zn²⁺ and gelatin, respectively. Then, a dual-response sensor with a wide operating temperature (-60 to 60 °C) is proposed, presenting high stress and temperature sensitivities and long-term stability. The sensor will meet the needs of the human-machine interface for scientific investigation and data monitoring in polar, desert, etc.