Stiffness switchable supramolecular hydrogels by photo-regulating crosslinking status

Stimuli-responsive hydrogels have been well known as a kind of promising functional material. Among them, intelligent supramolecular hydrogels constructed by covalent and non-covalent bonds have received increasing attention and been extensively researched. In this work we demonstrate a class of supramolecular hydrogels formed via host-guest interactions between coumarin and γ-cyclodextrin. Its stiffness can be modulated by photo-switching the weak physical crosslinking points to strong chemical crosslinking points. It is a simple and effective way to construct a dual-modality supramolecular hydrogel. Owing to the dynamic and reversible nature, the supramolecular hydrogels exhibit a bright future for the usage in self-healing and shape memory materials.