Conducting gelatin/PAM DN hydrogels with high mechanical properties prepared using the photoinduced one-pot method for strain sensors

Conductive hydrogels are widely used in biosensors, human–machine interfaces, and health recording electrodes. In this study, acrylamide and gelatin were introduced into the hydrogel. A conductive double-network hydrogel with high mechanical properties was prepared using the photoinduced one-pot method. The thermally reversible physical crosslinked gelatin constructed the first network, and the covalently crosslinked polyacrylamide formed the second one. The double networks increased the cross-linking strength between hydrogels; however, they dissipated energy and enhanced the mechanical properties. The addition of potassium chloride provided electrical conductivity for the hydrogels. The prepared double-network conductive hydrogel had high mechanical properties (tensile strength >800 KPa and tensile strain >1200%), good electrical conductivity (conductivity >0.9 S m−1), and excellent sensitivity (the gauge factor reached 1.88 when the strain was 400%). Moreover, a wide range of strain sensors was demonstrated based on gelatin/PAM DN hydrogels with high stability and durability, showing potential applications in wearable and fast response electronics.