Janus adhesion hydrogels with low hysteresis and high sensitivity toward precision flexible electronics underwater

Abstract

High toughness and low hysteresis are crucial for stable sensing in conductive hydrogels. Moreover, these hydrogels must exhibit robust frost resistance and superior interfacial adhesion to ensure accurate signal acquisition in challenging environments. In this study, a dual-network hydrogel with Janus adhesion is developed, exhibiting exceptional mechanical properties and environmental stability. The hydrogel demonstrates an exceptional strain at break of exceeding 1000 %, a low energy dissipation rate of 10.4 %, remarkable fatigue resistance, and frost resistance. These properties stem from the collective action of dynamic borate ester bonding, hydrogen bonding, and electrostatic interactions. Its broad-spectrum adhesion is attributed to the formation of multiple bonding interactions at the interface with the substrate, while its anti-adhesive characteristics arise from the hydrophobic polymethylsilsesquioxane (PMSQ) that forms in-situ on the surface. A sensor, based on this hydrogel, exhibits high sensitivity (GF = 7.39), a rapid response time of 161 ms, and long-cycle stability of 800 cycles, enabling real-time and precise monitoring of human motion. Furthermore, this sensor enables tactile sensing and pressure distribution analysis by incorporating flexible sensor arrays. Additionally, the sensor supports underwater motion monitoring and information transmission. This study presents a novel approach to the advancement of multifunctional Janus hydrogels for next-generation flexible electronics.