Conductive hydrogel with double network structure for robust and flexible wearable sensors.

A conductive hydrogel with double network structure was prepared by embedding Ag nanoparticles onto polyvinylpyrrolidone through in situ reduction, and subsequently crosslinking the mixture with polyvinyl alcohol and sodium lignosulfonate. This unique architecture imparted the hydrogel with good mechanical properties and fatigue resistance. Notably, the hydrogel exhibited remarkable antibacterial efficacy, achieving inhibition rates of 99.9 % against E. coli and 95.8 % against S. aureus. Furthermore, the conductive network, formed through the synergistic interaction of free ions and AgNPs, significantly enhanced both the conductivity and durability of the hydrogel sensor. The results demonstrated that the sensor maintained stable sensitivity even after 1000 cycles of stretching at 3 % and 30 % strain. In practical applications, this hydrogel sensor was successfully employed for real-time monitoring of various human body parts, including fingers, elbows, knees and facial expressions, underscoring its significant potential in the fields of flexible electronics and wearable sensing technologies.