Bio-inspired hydrogel-polymer brush bi-layered coating dramatically boosting the lubrication and wear-resistance

Surface modification is of great significance in improving the interfacial properties of bioimplants, especially friction and wear of artificial joint materials (e. g. polyetheretherketone, PEEK). Herein, inspired by the layered structure and gradient modulus of natural articular joint, hydrogel-polymer brush bilayered coating was developed to functionalize rigid PEEK (PBHP). The resulting PBHP material showed similar layered structure with natural articular joint. The load-bearing hydrogel layer and lubricating polymer brush layer exhibited corresponding moduli with natural cartilage and superficial biomacromolecules layer, respectively. Tribological tests demonstrated that the obtained material showed outstanding lubrication (friction coefficient<0.07), high load-bearing capability (load>20 N) and excellent wear-resistant capability (sliding cycles>10,000). The “hard PEEK-elastic hydrogel-soft polymer brush” layered material may find potential applications in artificial joint replacement.