Hydrogen-bonding reinforced robust hydrogels for load-bearing and sustained lubrication

The creation of bionic hydrogel characterized by optimal friction and load-bearing is essential for implantable artificial materials. High-stiffness and robust poly (methylacrylamide and methacrylic acid) hydrogels (P(MAAm-MAAc)) were synthesized using intensive cross-linking and intermolecular/intramolecular hydrogen bonding. Subsequently, an embedded lubricating layer was developed on the robust base, which formed layered structure similar to articular cartilage. It possesses distinctive mechanical characteristics (tensile strength: 3.9–4.4 MPa; elastic modulus: 27.8–38.6 MPa), along with superior lubricating and load-bearing capabilities. When water served as lubricant, the hydrogels exhibited low friction coefficient (COF ∼ 0.039), negligible wear, and sustained endurance over 18,000 sliding cycles. This high-stiffness and robust multilayer hydrogel possesses extensive application potential in bionic articular cartilage, medical devices, and other domains.