Glycosyl Radicals Induced Ultrafast and Homogeneous Gelation for Mechanically Robust Hydrogels.

Rapid gelation remains essential in maintaining uniform network structures and mechanical properties under mild conditions. Here, we report a strategy based on a glycosyl radical to achieve rapid gelation within tens of seconds. Mechanistically, glycosyl sulfinates serve as efficient precursors to glycosyl radicals upon treatment with potassium persulfate (KPS) through a single-electron transfer process. The following polymerization process exhibits a gentle increase in exotherms and viscosity, which promotes the homogeneity of the polymer network. Glycosyl units are partially incorporated into polymer chains as hydroxyl-rich termini with the remainder freely dispersed throughout the hydrogel matrix, both forming extensive dynamic hydrogen bonds with polymer backbones. Consequently, the hydrogels exhibit exceptional mechanical performance, including high strength, toughness, elasticity, and fatigue resistance. This robust method is compatible with various vinyl monomers, glycosyl sulfinate derivatives, and even harsh environmental conditions. As a proof-of-concept application, the precursor solution can rapidly form uniform gel films via controlled spraying, highlighting potential applications in flexible electronics, wearable sensors, and biomedical dressings.