Quantification of Surface Morphology of Lubricant Films with Functional End Groups by Using Molecular Dynamics Simulation: Periodic Change of Morphology Depending on Film Thickness

摘要

Coarse-grained molecular dynamics simulations using a bead-spring model were applied to investigate the distribution of lubricant films with functional end groups on solid surfaces as a function of film thickness. We introduced a molecular-probe scanning method analogous to the scanning probe microscopy to identify the surface morphology of the lubricant thin films on a molecular scale. Root mean square roughness was calculated to quantify the effect of film thickness on the surface morphology. We found that the surface roughness of the lubricant films changed periodically as the film thickness increased and that this was caused by the characteristic conformation of the lubricant molecules inside the films.