Fast self-healing zwitterion nanocomposite hydrogel for underwater sensing

Conductive hydrogels have consistently attracted researchers' interests in the past few years. However, challenges still remain in the preparation of hydrogels with self-healing ability and underwater sensing capacity. In this work, we fabricate a novel fully-physically crosslinked nanocomposite hydrogel by incorporating gelatin dispersed carbon nanotubes (CNTs) into poly (sulfobetaine methacrylate) (PSBMA) network. The fully physically crosslinked PSBMA backbone and the nano reinforcement of CNTs endow hydrogel with fast self-healing ability (about 30 s) and good mechanical properties. Additionally, PSBMA/CNTs hydrogels exhibit high strain sensitivity (gauge factor up to 10.35) and pressure sensitivity (up to 0.256 kPa−1) and they can be fabricated as strain and pressure sensors to precisely monitor human movements. Moreover, the PSBMA/CNTs hydrogel sensor can detect human motions underwater owing to the anti-swelling feature. This work provides a feasible method to construct self-healing hydrogel sensors with strain and pressure sensing capacity and paves a way for underwater human motion sensors.