Rapidly recoverable, anti-fatigue, super-tough double-network hydrogels reinforced by macromolecular microspheres.

In this study, a novel strategy was designed to prepare rapidly recoverable, anti-fatigue, super-tough double-network hydrogels by introducing macromolecular microspheres (MMs) as cross-linking centers for hydrophobic associations. MMs were prepared via emulsion polymerization using butyl acrylate (BA) as a main component and dicyclopentyl acrylate (DCPA) as a cross-linker. Then, a double-network (DN) hydrogel was prepared using gelatin as the first network and a copolymer of acrylamide and hexadecyl methacrylate stabilized by MMs as the second network. As a result, the DN hydrogels that were toughened by MMs exhibited an excellent fracture strength of 1.48 MPa and a fracture strain of 2100%. Moreover, the hydrogels exhibited rapid recoverability and fatigue resistance. Therefore, the strategy would open up a novel avenue for the toughening of DN hydrogels for biomedical applications.