Enhancing Water Lubrication in UHMWPE Using Mesoporous Polydopamine Nanoparticles: A Strategy to Mitigate Frictional...

Establishing a persistent lubrication mechanism and a durable tribo-film on contact surfaces is identified as crucial for improving the tribology and vibration characteristics of polymer materials under water-lubricated conditions. This study focuses on enhancing tribological performance and reducing frictional vibrations in ultrahigh molecular weight polyethylene (UHMWPE) through the incorporation of mesoporous polydopamine (MPDA) nanoparticles. In the experiments, MPDA nanoparticles were synthesized and blended with UHMWPE to create UHMWPE/MPDA composites. The interactions between these composites and zirconia (ZrO₂) ceramic balls under water lubrication were examined. The results show that when the MPDA content of the composite is 1.5 wt %, the coefficient of friction and wear rate are reduced by 40% and 52% compared with those of pure UHMWPE, respectively. This notable enhancement helped to mitigate friction-induced vibrations, particularly those caused by intermittent sticking and slipping motions. MPDA nanoparticles were shown to act as reservoirs for water, releasing and replenishing water based on the loading conditions, which sustained continuous water-based lubrication at the composite surfaces. Additionally, the surface deformation behavior of the composite material is significantly weakened, which provides a more stable friction surface. This work introduces a novel approach to enhance the interface stability of polymers in water-lubricated environments, offering guidance for developing advanced materials and reducing friction and wear in engineering applications.