Modified Cahn model for surface tension with the presence of a contact line applied to regular solutions

TL;DR

This paper extends the Cahn model to include a surface free energy term, demonstrating its importance in accurately describing interfacial tension in partially miscible binary mixtures near a contact line.

Contribution

The paper introduces a modified Cahn model incorporating a surface free energy term, highlighting its significance for regular solutions in contact line problems.

Findings

Surface free energy term significantly affects interfacial tension calculations.

Modified model provides more accurate predictions for partially miscible fluid interfaces.

Neglecting the surface free energy term can lead to inaccuracies in interfacial tension estimates.

Abstract

We derive the interfacial tension of a semi infinite two phase binary mixture of partially miscible fluids in contact with a planar surface. In our model we take a surface free energy term into account omitted by Cahn [J. W. Cahn, J. Chemical Physics, 66:3667-3672,1977]. Our analysis applied to the case of regular solutions shows that this extra surface free energy term cannot a priori be neglected.