Knowledge of the interfacial properties of water/oil mixtures is extremely important for the petrochemical industry and for understanding detergency and hydrophobic effects. In 2010, Javadi et al.1 observed a significant decrease in the surface tension of water when alkanes, including n-hexane, adsorbed from the vapor phase onto the surface. Mucic et al.2 found that the surface tension of water decreases with increasing (partial) pressure of n-hexane. Here, we probe the liquid/vapor interface of water/n-hexane mixtures using configurational-bias Monte Carlo simulations in the NpNAT Gibbs ensemble where one box contains a liquid film with constant area and applied normal pressure and the other represents the isotropic vapor phase. We study the effect of n-hexane, at several different partial pressures, on the liquid/vapor surface tension, and analyze the simulation trajectories to determine the n-hexane loading and to provide molecular-level insights on the structure of the interface.

Monte Carlo simulations probing the liquid/vapor interface of water/hexane mixtures

253rd National Meeting (2017)

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