Coarse-grained Molecular Dynamics Study of Effect of Surface Roughness on Adsorption Behavior of Fatty Acid Additives in Lubricating Oil

Abstract

Coarse-grained molecular dynamics simulations were performed to compare the adsorption of organic friction modifier (OFM) added in lubricating oil to flat and corrugated surfaces. Stearic acid, dodecane, and hematite were used as the OFM, lubricating oil, and solid surfaces, respectively. The simulation results showed that the increase in the surface number density of adsorbed stearic acid molecules in 100 ns simulations at 353 K was approximately four times faster on the corrugated surface than on the flat surface. We infer that surface roughness may promote adsorption of OFM additives, owing to the enhanced liquid–solid interactions at the corners formed between adjacent layers of solid surfaces.