One-pot fabrication of robust interpenetrating hydrogels via orthogonal click reactions
Interpenetrating polymer network (IPN) hydrogels have been fabricated through a facile one-pot approach from tetra/bifunctional telechelic macromonomers with epoxy, amine, azide, and alkyne groups by orthogonal double click reactions: epoxy-amine reaction and copper-catalyzed azide-alkyne cycloaddition. Both the crosslinked networks are simultaneously constructed in water from the biocompatible poly (ethylene glycol)-based macromonomers. The crosslinking density of each network was finely tuned by the macromonomer structure, permitting control of network molecular weights between crosslinks of the final gels. Compared to corresponding single network gels, the IPN gels containing both tightly and loosely crosslinked networks exhibited superior mechanical properties with shear moduli above 15 kPa and fracture stresses over 40 MPa. The synthetic versatility of this one-pot approach will further establish design principles for the next generation of robust hydrogel materials.