Tribological behavior of the PDA/PTFE + Cu-SiO2 nanoparticle thin coatings

Cu-SiO2 core-shell nanoparticles (NPs) were added to the polytetrafluoroethylene (PTFE) top layer of polydopamine (PDA)/PTFE thin coatings to improve the durability of the coatings. Three very low weight percentages of Cu-SiO2 NPs (0.005 wt%, 0.0075 wt%, 0.01 wt%) were added to a PTFE dispersion, which was then used to dip-coat the PTFE + Cu-SiO2 NPs onto PDA-coated stainless steel substrates to form PDA/PTFE + Cu-SiO2 NP thin coatings. The resulting thin coatings were less porous and had smaller surface roughness compared to PDA/PTFE thin coatings, revealing the effect of Cu-SiO2 NPs in making more compact thin coatings with interconnected PTFE fibrils. The compaction of the coatings led to improved adhesion and durability of the PDA/PTFE + Cu-SiO2 NP thin coatings. •Cu-SiO2 core-shell nanoparticles (NPs) were added to PTFE coatings on adhesive PDA.•Surface and tribological properties of the PDA/PTFE + NP coatings were studied.•PDA/PTFE + NP coatings are more coherent and interconnected with less porosity.•Low concentrations of Cu-SiO2 NPs prevented global coating delamination.•Adding 0.0075 wt% Cu-SiO2 NPs improved the PDA/PTFE coating life two times.