Molecular dynamics study of the interfacial slip phenomenon in ultrathin lubricating films

The tribological performance of thin films of a liquid alkane has been studied through a molecular dynamics simulation with particular attention being paid to the phenomenon of interfacial slip. The model system for the simulation consists of two solid walls, with the lubricant molecules confined between them. Molecules of n-decane (C₁₀H₂₂) were chosen to represent the lubricant molecules. The results of the simulation show: the average velocity of decane molecules in a Couette flow exhibits largely a linear distribution, but with a slip velocity at the solid-liquid interface; when the simulations are performed at different temperatures, the slip ratios were found to vary with temperature; slip behaviour depends strongly on the solid-fluid interaction; and slip ratios increase with decreasing film thickness, suggesting that slip in the thin films is a confinement-related phenomenon.