Enhancing Water Lubrication\nin UHMWPE Using Mesoporous\nPolydopamine Nanoparticles: A Strategy to Mitigate Frictional Vibration

Establishing a persistent lubrication mechanism and a\ndurable tribo-film\non contact surfaces is identified as crucial for improving the tribology\nand vibration characteristics of polymer materials under water-lubricated\nconditions. This study focuses on enhancing tribological performance\nand reducing frictional vibrations in ultrahigh molecular weight polyethylene\n(UHMWPE) through the incorporation of mesoporous polydopamine (MPDA)\nnanoparticles. In the experiments, MPDA nanoparticles were synthesized\nand blended with UHMWPE to create UHMWPE/MPDA composites. The interactions\nbetween these composites and zirconia (ZrO<sub>2</sub>) ceramic balls\nunder water lubrication were examined. The results show that when\nthe MPDA content of the composite is 1.5 wt %, the coefficient of\nfriction and wear rate are reduced by 40% and 52% compared with those\nof pure UHMWPE, respectively. This notable enhancement helped to mitigate\nfriction-induced vibrations, particularly those caused by intermittent\nsticking and slipping motions. MPDA nanoparticles were shown to act\nas reservoirs for water, releasing and replenishing water based on\nthe loading conditions, which sustained continuous water-based lubrication\nat the composite surfaces. Additionally, the surface deformation behavior\nof the composite material is significantly weakened, which provides\na more stable friction surface. This work introduces a novel approach\nto enhance the interface stability of polymers in water-lubricated\nenvironments, offering guidance for developing advanced materials\nand reducing friction and wear in engineering applications.