Monte Carlo Simulation Strategies to Compute the Interfacial Properties of a Model Octane-Water-Silica System

We use Monte Carlo simulation to study the wetting properties of a model octane-water-silica system. Two versions of the interface potential are employed to characterize the wetting behavior. The water spreading interface potential focuses on the growth of a water-rich film from a silica surface in the presence of an octane-rich fluid. The octane spreading interface potential focuses on the growth of an octane-rich film from a silica surface in the presence of a water-rich fluid. These interface potentials provide direct measures of two spreading coefficients that are combined to obtain the octane-water interfacial tension and the contact angle of a water-rich droplet at a silica surface in a mother octane-rich fluid. We demonstrate how to utilize the approach to determine the interfacial properties of a model system (SPC/E water, TraPPE octane, and Lee and Rossky silica) over a wide range of temperatures and pressures. Results are presented for the variation in the interfacial tension and the contact angle with pressure at a constant temperature and along the liquid-liquid-vapor triple line. Finally, we briefly examine how wetting properties vary upon modification of the surface hydrophilicity.