Rapid gelation of dual physical network hydrogel with ultra-stretchable, antifreezing, moisturing for stable and sensitive response

Dual physical network hydrogel possesses robust energy dissipation mechanism. However, the demanding conditions of the second monomer radical polymerization aren't benefit for the dispersion of conductive filler. Moreover, the stable and sensitive response under extreme environment puts forward the requirements for mechanical, antifreezing and moisture retention properties. Herein, a dual physical networks hydrogel (polyacrylic acid-chitosan-graphene/glycerol, noted as PAA-CS-G/Gly) was prepared rapidly (<0.5 h) without chemical cross-linking agents at room temperature. The rapid gelation, ionic coordination of Ag + together with certain viscosity chitosan promoted the dispersion of graphene. PAA-CS-G/Gly showed ultra-stretchable properties (~2500%), good toughness (3.11 MJ/m 3 ), breaking strength (0.27 MPa) and fatigue resistance. PAA-CS-G/Gly had good adhesion properties, outstanding tolerance for freezing (−80°C) and moisture retention. More importantly, PAA-CS-G/Gly strain sensor had excellent sensitivity (GF, up to 9.449) at 300% ~ 900% strain. It could sensitively detect human joint movements and even subtle activities such as talking and swallowing. PAA-CS-G/Gly hydrogel is expected to adhere directly to the human body for flexible monitoring of human size movement under extreme environmental conditions.