Surface Tension of Electrolyte Solutions: A Self-consistent Theory
Abstract
We study the surface tension of electrolyte solutions at the air/water and oil/water interfaces. Employing field-theoretical methods and considering short-range interactions of anions with the surface, we expand the Helmholtz free energy to first-order in a loop expansion and calculate the excess surface tension. Our approach is self-consistent and yields an analytical prediction that reunites the Onsager-Samaras pioneering result (which does not agree with experimental data), with the ionic specificity of the Hofmeister series. We obtain analytically the surface-tension dependence on the ionic strength, ionic size and ion-surface interaction, and show consequently that the Onsager-Samaras result is consistent with the one-loop correction beyond the mean-field result. Our theory fits well a wide range of concentrations for different salts using one fit parameter, reproducing the reverse Hofmeister series for anions at the air/water and oil/water interfaces.10.1029
Cite
@article{arxiv.1305.3142,
title = {Surface Tension of Electrolyte Solutions: A Self-consistent Theory},
author = {Tomer Markovich and David Andelman and Rudi Podgornik},
journal= {arXiv preprint arXiv:1305.3142},
year = {2014}
}
Comments
5 pages, 2 figures