Zwitterionic Functionalized Negatively Charged Hydrogel/Ti6Al4V Alloy with Superior Lubrication Performance

Traditional artificial joints mainly face the challenges of severe wear and aseptic loosening, which limits their application as joint bearing interfaces under high-stress loading conditions. To improve this problem, inspired by the gradient modulus structure of natural cartilage/subchondral bone and the inherent negative charge characteristics of the surface, a negatively charged hydrogel layer was adhered to a porous Ti6Al4V surface through a combination of ultraviolet irradiation and freeze–thaw cycles. The cross-sectional SEM image exhibited that the hydrogel layer was closely bonded to the hard substrate. After physical doping with SBMA, the lubrication performance of the composite bearing interface was significantly improved, primarily attributable to the biphasic lubrication of the hydrogel layer and the hydration lubrication mechanism of SBMA.