A Mechanically Robust, Stiff, and Tough Hyperbranched Supramolecular Polymer Hydrogel

Abstract In this study, a simple yet versatile method is introduced to prepare a hyperbranched supramolecular polymer hydrogel by utilizing Type II photoinitiated self‐condensing vinyl polymerization of N ‐acryloyl glycinamide, which can serve not only as an inimer providing branching sites, but also as a hydrogen‐bonding cross‐linker. The hyperbranched poly( N ‐acryloyl glycinamide) (HB‐PNAGA) hydrogels demonstrate excellent mechanical performances with a tensile strength of 0.793–2.724 MPa, elongation at break of 203–902%, Young's modulus of 0.450–1.172 MPa, and maximal fracture energy of 2200 J m −2 , which are all superior to those of linear PNAGA hydrogels. The results indicate that the HB‐PNAGA hydrogel is very stiff and tough due to much higher H‐bonding cross‐linking density formed in hyperbranched architecture. The high stiffness, toughness, and ease of preparation make these hyperbranched supramolecular hydrogels very attractive for application as soft supporting tissue replacements.