Structure of Interfacial Water on Quartz and its Self-diffusion Coefficient Revealed by Molecular Dynamics Simulations

Abstract

Molecular dynamics (MD) simulations were performed to investigate the self-diffusion coefficient and density profile of water confined between quartz (1010) surfaces at 298-573 K. The self-diffusion coefficient of confined water was lower than that of bulk water. In the thickness less than 1 nm, the self-diffusion coefficient was significantly lower even at high temperature. The density profiles of H2O molecules showed several layered structures near the surface at all temperature conditions. The result at 298 K was consistent to that obtained in a previous experimental study. Therefore the silanol group on quartz surfaces might play a significant role for the dynamics and structure of interfacial water on quartz and our simulation model could provide information about the effect of surface silanol group for structure and dynamics of interfacial water.