Molecular Dynamics Simulation of Tolman Length and Interfacial Tension of Symmetric Binary Lennard-Jones Liquid

The Tolman length and interfacial tension of partially miscible symmetric binary Lennard-Jones (LJ) fluids (A, B) was revealed by performing a large-scale molecular dynamics (MD) simulation with a sufficient interfacial area and cutting distance. A unique phenomenon was observed in symmetric binary LJ fluids, where two surfaces of tension existed on both sides of an equimolar dividing surface. The range of interaction epsilon(AB) between the different liquids and the temperature in which the two LJ fluids partially mixed was clarified, and the Tolman length exceeded 3 sigma when epsilon(AB) was strong at higher temperatures. The results show that as the temperature or epsilon(AB) increases, the Tolman length increases and the interfacial tension decreases. This very long Tolman length indicates that one should be very careful when applying the concept of the liquid-liquid interface in the usual continuum approximation to nanoscale droplets and capillary phase separation in nanopores.

Automated summary

By performing a large-scale molecular dynamics simulation, the Tolman length and interfacial tension of partially miscible symmetric binary LJ fluids were studied. It was found that two surfaces of tension exist in symmetric binary LJ fluids, and the temperature range and interaction epsilon(AB) affecting the partial mixing of the two fluids were clarified. The results show that the Tolman length increases and the interfacial tension decreases as the temperature or epsilon(AB) increases.