A molecular dynamics study on water lubrication of PTFE sliding against copper

The tribological models of the PTFE sliding against Copper (Cu) layer under dry friction and water lubrication were developed by a molecular dynamics (MD) simulation to examine the friction coefficient and wear process from an atomic view, respectively. The average friction coefficient of PTFE in the steady stage decreased from 0.189 to 0.064 after water lubrication. Water lubrication dramatically reduced the wear of PTFE compared with dry friction. The molecular interactions among PTFE molecules, water molecules and Cu atoms were interpreted by analyzing the variations of the radius distribution function (RDF), relative concentrations and velocity in the thickness direction. The water lubrication mechanisms were discussed by monitoring the potential energy and temperature variations during the process of friction.