Thermoelectric-driven temperature-sensing multifunctional hydrogel for smart applications

Conductive hydrogels, valued for their ease of fabrication, mechanical flexibility, high stretchability, and excellent biocompatibility, are extensively utilized as core components in electronic skin and wearable sensors. However, their applications in complex environments remain limited by insufficient multifunctionality and dependence on single-sensing mechanisms, such as strain-responsive resistance changes. In this study, we innovatively introduced two-dimensional layered double hydroxides (LDH) into conductive hydrogels to create a multifunctional hydrogel primarily crosslinked through electrostatic interactions. This design integrated high mechanical properties, self-healing capabilities, strong adhesiveness, environmental stability (water retention and freeze resistance), and dual sensing capabilities. Unlike conventional strain-responsive hydrogels, our material leveraged skin-inspired thermoelectric effects to achieve temperature sensing, exhibiting a Seebeck coefficient of 3.04 mV K -1 . When adhered to skin, it detected high-temperature threats within 2 seconds with rapid warning response. By transcending deformation-dependent resistance sensing, this work pioneered a skin-inspired thermoelectric approach, offering a paradigm for hazard detection and multidimensional sensing in electronic skin and adaptive electronic interfaces. • Innovatively added 2D LDH into hydrogels, boosting thermoelectricity (3.04 mV K -1 ) via enhanced water-LDH interfaces. • Prepared electrostatically crosslinked hydrogel with balanced mechanical-adhesion (51.7 kPa), strength (247.3 kPa), self-healing and thermoelectricity. • Developed thermoelectric hydrogel sensor (for fire alarms within 4 seconds) breaking strain-only tradition, enabling e-skin temperature/multidimensional sensing.