Interfacial tension behavior of binary and ternary mixtures of partially miscible Lennard-Jones fluids: A molecular dynamics simulation

By means of extensive equilibrium molecular dynamics simulations we have investigated the behavior of the interfacial tension γ of two immiscible symmetrical Lennard-Jones fluids. This quantity is studied as function of reduced temperature T*=kBT/ε in the range 0.6⩽T*⩽3.0. We find that, unlike the monotonic decay obtained for the liquid-vapor interfacial tension, for the liquid–liquid interface, γ(T) has a maximum at a specific temperature. We also investigate the effect that surfactantlike particles have on the thermodynamic as well as the structural properties of the liquid–liquid interface. It is found that γ decays monotonically as the concentration of the surfactantlike particles increases.