Molecular dynamics simulation of friction of hydrocarbon thin films

Molecular Dynamics (MD) simulations were performed to investigate the dynam ic behavior of hydrocarbon molecules under shear conditions. Frictional pro perties of cyclohexane, n-hexane, and iso-hexane thin films confined betwee n two solid surfaces were calculated. Because the affinity of the solid sur faces in these simulations is strong, slippages occurred at inner parts of the confined films, whereas no slippages were observed at the solid boundar ies. The hexagonal closest packing structure was observed for the adsorbed cyclohexane molecular layers. The branched methyl groups in the iso-hexane molecules increase the shear stress between the molecular layers. For the n -hexane monolayer, molecules were observed to roll during the sliding simul ations. Rolling of the n-hexane molecules decreased the shear stress.