A conductive hybrid hydrogel with high toughness and fatigue resistance for wearable sensor

Hydrogel is a soft biomaterial with high water content that has attracted increasing attention due to its many advantages, such as excellent biocompatibility and shape controllability. However, conventional hydrogel materials have the defects of complex preparation process, low mechanical properties and poor stability, and it is still a great challenge to prepare hydrogels with excellent performance by a simple method. In this study, a method of solvent replacement by immersion was introduced to prepare polyvinyl alcohol/nickel ion (PVA/Ni²⁺) hydrogels with excellent performance. The hydrogel exhibits excellent tensile properties (elongation at break of 580 %), very high mechanical strength (1.1 MPa), excellent mechanical stability and fatigue resistance. Strikingly, this hydrogel also has good electrical conductivity, and strain sensors based on the hydrogel show an impressive upper detection (more than 300 %), with sensitivity to detect strain as low as 1 %, short response times, and the ability to accurately capture human movement behavior. This work achieves the combination of good mechanical properties and excellent sensing performance, which provides a good idea for the further development of flexible wearable sensing devices.