Fishnet-inspired dual-crosslinked nanocomposite hydrogels with core-shell SiO2@ZnO for self-powered sensing and intelligent mobility assistance systems

Enhancing the toughness, conductivity and adhesion of hydrogels while reducing hysteresis is crucial for the development of flexible hydrogel sensors. Inspired by fishing nets, silica-coated zinc oxide core-shell nanoparticles (SiO 2 @ZnO) with unsaturated double bonds on their surface were synthesized through an in-situ sol-gel method. These nanoparticles were incorporated into 2-acrylamido-2-methylpropane sulfonic acid (AMPS), forming a double-crosslinked, nano-SiO 2 reinforced multifunctional composite hydrogel (SiO 2 @ZnO/PAMPS, PAS) through radical polymerization. The results show that the hydrogel has a low hysteresis rate of less than 10 % at a breaking strain of 1412 %, and the adhesion strength with pig skin, which simulates human skin, reaches 34.79 kPa. Additionally, strain sensors based on this hydrogel show a high sensitivity value of 1.26 and a fast response time (214 ms) within a strain range of 200–700 %. Furthermore, a triboelectric nanogenerator (TENG) based on PAS demonstrates an open-circuit voltage of 131.2 V and a power density of 239.13 mW/m 2 . This TENG can function not only as a power source for electronic devices but also detect differences signal generated while walking on surfaces with different texture. By integrating it with a Bluetooth system, a self-powered intelligent pavement wireless sensing system aimed at aiding the mobility of the visually impaired has been developed, highlighting the potential application of PAS hydrogel sensors in self-powered sensing fields.