Versatile preparation of jellyfish-inspired color transition hydrogels via polymerization induced supramolecular geletion (PISG)

Supramolecular hydrogels based on host–guest interactions constitute a class of intriguing soft matter and have attracted great attention due to their unique properties, etc. In this study, we successfully synthesized 4-methylene-7-diethylaminocoumarin methacrylate (DEACMMA) monomer and carried out reversible addition-fragmentation chain transfer (RAFT) polymerization using methylated β-cyclodextrin via a host-guest encapsulation mechanism. This process led to the formation of ternary copolymer hydrogel supramolecular photoresponsive hydrogels through polymerization induced supramolecular gelation (PISG). The encapsulation of coumarin monomers by methylated cyclodextrins was confirmed using 2D ROESY NMR and fluorescence spectroscopy. We have carefully analyzed the microstructure of these supramolecular hydrogels by rheological profiles and scanning electron microscopy (SEM). Stimulated by UV light, the copolymers transition from non-luminescence to a bright fluorescent blue color, which is reminiscent of the self-transforming colors observed in jellyfish. The development of photostimuli-responsive hydrogels based on methylated β-cyclodextrin-coated coumarin esters opens new avenues in the fields of smart materials and clinical medicine.