Rapidly self-recoverable and fatigue-resistant hydrogels toughened by chemical crosslinking and hydrophobic association

Designing load-bearing hydrogels with superior toughness and stiffness are crucially important for cartilage replacement and tissue engineering. In this investigation, we report that hybrid hydrogels can simultaneously achieve high stiffness and toughness by introducing covalent and physical interactions. The chemical crosslinking can sustain hydrogel networks as a rigid component and the hydrophobic association is introduced as a dynamic crosslinking center for efficient energy dissipation. The storage modulus G′ can reach nearly 40   kPa and the compression stress was nearly 8   MPa at 95% compression strain. Moreover, the hybrid hydrogel exhibited time-dependent, rapid self-recoverable and fatigue resistant behavior based on the cyclic loading-unloading compression test. The hybrid hydrogels with excellent self-recovery and fatigue resistance would provide a large number of potential applications, such as artificial cartilages and muscles and scaffolds for tissue engineering .