High-Performance Triple-Network Hydrogels Derived from Chrome Leather Scraps: Ultrahigh Compressive Strength, Adhesion, and Self-Recovery

The development of engineered hydrogels with high strength, self-recovery, and adhesion is essential for applications requiring resistance to large deformations and cyclic loading. Herein, a triple-network (TN) hydrogel with ultrahigh compressive strength, strong adhesion, and good self-recovery was constructed by using tannic acid-modified chrome leather scrap hydrolysate as the first network, polyacrylamide as the second network, and poly-2-propenamide-2-methylpropanesulfonic acid as the third network. The ultrahigh (70 MPa compressive strength and 95% compression deformation) TN hydrogels were effectively created, which is attributed to the synergy of the three networks. The TN hydrogels display adhesion (adhesion strength > 20 kPa) ascribed to the introduction of phenolic hydroxyl groups in tannic acid. Intriguingly, the TN hydrogels exhibit excellent self-recovery performance (93.6% dissipated energy recovery at 70 °C) and shape memory performance (restored to the original shape in 20 s). These properties are essential for the development of high-performance hydrogels and promote the resource utilization of leather waste.