Tough and Conductive Dual Physically Cross-Linked Hydrogels for Wearable Sensors

It is imperative to achieve excellent mechanical and electrical properties in a single hydrogel. Herein, based on hydrogen bonds and hydrophobic associations, poly(N-hydroxymethyl acrylamide) hydrophobic association hydrogels (PHMA HA gels) with dual physically cross-linked networks were prepared through micellar copolymerization of HMA and stearyl methacrylate (C-18) under the action of a surfactant and sodium chloride (NaCl). Under optimal conditions, PHMA HA gels could achieve excellent tensile strength (1.09 MPa) and high toughness (1509 J/m(2)). Additionally, PHMA HA gels exhibited outstanding self-recovery and self-healing properties as well as high conductivity, and they could serve as sensors of strain and pressure to monitor human movements. It is believed that PHMA HA gels with integrated high performances have broad application prospects in wearable electronics.