Stretchable and Self-Powered Temperature–Pressure Dual Sensing Ionic Skins Based on Thermogalvanic Hydrogels

Tactile sensors with both temperature- and pressure-responsive capabilities are critical to enabling future smart artificial intelligence. These sensors can mimic haptic functions of human skin and inevitably suffer from tensile deformation during operation. However, almost all actual multifunctional tactile sensors are either nonstretchable or the sensing signals interfere with each other when stretched. Herein, we propose a stretchable and self-powered temperature-pressure dual functional sensor based on thermogalvanic hydrogels. The sensor operates properly under stretching, which relies on the thermogalvanic effect and constant elastic modulus of hydrogels. The thermogalvanic hydrogel elastomer exhibits an equivalent Seebeck coefficient of -1.21 mV K^-1 and a pressure sensitivity of 0.056 kPa^-1. Combined with unit array integration, the multifunctional sensor can be used for accurately recording tactile information on human skin and spatial perception. This work provides a conceptual framework and systematic design for stretchable artificial skin, interactive wearables, and smart robots.