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

TL;DR

This study uses molecular dynamics simulations to analyze how interfacial tension varies with temperature and surfactant concentration in binary and ternary Lennard-Jones fluid mixtures, revealing unique temperature-dependent behaviors.

Contribution

It provides new insights into the temperature dependence of interfacial tension and the impact of surfactant-like particles on Lennard-Jones fluid interfaces, which was not previously detailed.

Findings

Interfacial tension exhibits a maximum at a specific temperature for liquid-liquid interfaces.

Surfactant-like particles cause a monotonic decrease in interfacial tension with increasing concentration.

Distinct behavior compared to liquid-vapor interfacial tension decay.

Abstract

By means of extensive equilibrium molecular dynamics simulations we have investigated, the behavior of the interfacial tension $\gamma$ of two immiscible symmetrical Lennard-Jones fluids. This quantity is studied as function of reduced temperature $T^{*}={{k_{_B} T}\over \epsilon}$ in the range $0.6 \leq T^{*} \leq 3.0$. We find that, unlike the monotonic decay obtained for the liquid-vapor interfacial tension, for the liquid-liquid interface, $\gamma (T)$ has a maximum at a specific temperature. We also investigate the effect that surfactant-like particles has on the thermodynamic as well as the structural properties of the liquid-liquid interface. It is found that $\gamma$ decays monotonically as the concentration of the surfactant-like particles increases.