Muscle Contraction-Inspired Tough Hydrogels

In many animals, tough skeletal muscle contraction occurs, producing a strong force through myofilaments attaching to and sliding on fibrous actin filaments. In contrast, the strength of typical synthetic hydrogels is facilitated mainly by polymeric chains. We propose a strategy for developing strong and tough hydrogels in which the side groups on polymeric chains strongly interact with dispersing medium. The hydrogels are fabricated with a polyacrylamide–alginate double network in a choline chloride saturated solution. The hydrogels are not only highly transparent, tough, fatigue-resistant, self-recovering, self-healing, and adhesive but also water-retentive, antifreezing, and conductive. The hydrogels are strengthened by hydrogen bonds in dispersing medium with a clathrate framework structure. This work may inspire the development of tough and conductive gels for applications of e-skins, soft robots, and intelligent devices.