title: Surface tension of electrolyte interfaces: ionic specificity within a field-theory approach.
abstract: We study the surface tension of ionic solutions at air/water and oil/water interfaces by using field-theoretical methods and including a finite proximal surface-region with ionic-specific interactions. The free energy is expanded to first-order in a loop expansion beyond the mean-field result. We calculate the excess surface tension and obtain analytical predictions that reunite the Onsager-Samaras pioneering result (which does not agree with experimental data), with the ionic specificity of the Hofmeister series. We derive 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 salt concentrations for different monovalent ions using one fit parameter per electrolyte and reproduces the reverse Hofmeister series for anions at the air/water and oil/water interfaces.
authors: Raymond and Beverly Sackler School of Physics and Astronomy, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel.
authors: Tomer
authors: T
authors: Markovich
authors: Raymond and Beverly Sackler School of Physics and Astronomy, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel.
authors: David
authors: D
authors: Andelman
authors: Department of Theoretical Physics, J. Stefan Institute and Department of Physics, Faculty of Mathematics and Physics, University of Ljubljana, 1000 Ljubljana, Slovenia.
authors: Rudi
authors: R
authors: Podgornik