Inhomogeneous surface tension of chemically active fluid interfaces

TL;DR

This paper investigates how the surface tension of fluid interfaces varies with the density profile of an attached phase, revealing non-monotonous behavior and local variations through an approximate and perturbative model.

Contribution

It introduces a new model and analytical formulas to describe inhomogeneous surface tension influenced by the density distribution of a third phase.

Findings

Surface tension depends non-monotonously on the density peak of the suspended phase.

The model predicts local surface tension variations for non-uniform density profiles.

Analytical formulas provide insights into the free energy and surface tension of the system.

Abstract

We study the dependence of the surface tension of a fluid interface on the density profile of a third suspended phase. By means of an approximated model for the binary mixture and of a perturbative approach we derive close formulas for the free energy of the system and for the surface tension of the interface. Our results show a remarkable non-monotonous dependence of the surface tension on the peak of the density of the suspended phase. Our results also predict the local value of the surface tension in the case in which the density of the suspended phase is not homogeneous along the interface.