Visible and selective gel assembly via covalent click chemistry

Abstract This study marks the birth of visible and selective click covalent assembly. It is achieved by amplifying orthogonal alkyne−azide click chemistry through interfacial multisite interactions between azide/alkyne functionalized polymer hydrogels. Macroscopic assembly of hydrogels via host−guest chemistry or noncovalent interactions such as electrostatic interactions has been reported. Unlike macroscopic supramolecular assembly, here we report visible and selective “click” covalent assembly of hydrogels at the macroscale. LEGO‐like hydrogels modified with alkyne and azide groups, respectively, can click together via the formation of covalent bonds. Monomer concentration‐dependent assembly and selective covalent assembly have been studied. Notably, macroscopic gel assembly clearly elucidates click preferences and component selectivity not observed in the solution reactions of competing monomers.