Abstract
A fundamental understanding of diffusion phenomena of submonolayer polar liquid films is important to achieve reliable lubrication. With the aim of gaining such an understanding, we developed an all-atom model that includes hydrogen-bond potential for polar perfluoro- polyether Zdol molecules and carried out MD simulations using this model. Comparing with experimental results, we confirmed that our MD simulations reproduce the effects of polar groups on the diffusion and conformation of Zdol molecules. Our MD simulations also demonstrated that, as the thickness of submonolayer Zdol films decreased, the molecular conformation changed from spherical to flat and the diffusion coefficient decreased. We suggest that such a change in the molecular conformation is the reason for the decrease of diffusion coefficient.
