One-pot solvent exchange preparation of non-swellable, thermoplastic, stretchable and adhesive supramolecular hydrogels based on dual synergistic physical crosslinking

With their unique properties of self-healing and viscoelasticity, physically crosslinked supramolecular hydrogels are promising materials for soft robotics, wearable electronics and biomedical applications. However, the weak mechanical properties of supramolecular hydrogels, especially those prepared with natural polymers, limit their wide-spread application, and swelling is one of the key factors that contributes to the weakening of hydrogels. Herein, we utilize a simple one-pot solvent exchange method to prepare non-swellable, thermoplastic and tough supramolecular gelatin hydrogels based on two synergistic physical crosslinkings, namely, the self-assembled tri-helix structure of gelatin and the hydrophobic aggregation of gelatin-grafted and free hydrophobic motifs. The obtained hydrogels possess a stable water content above 70% with extended incubation in water. These hydrogels are highly malleable upon heating but are extremely stretchable and tough after cooling to room temperature. Furthermore, the supramolecular gelatin hydrogels exhibit robust adhesion to various material surfaces and minimal cytotoxicity.