Physics of the surface tension at the interface of electrolyte solutions

Abstract

Most electrolytes increase the surface tension of water. According to thermodynamics, this leads to a repulsive force between the gas–liquid interface and the ions. The thermodynamic properties and the computational theory of surface tension are first introduced. Subsequently, a quantitative comparison of ion adsorption for individual ion species is presented based on a theoretical analysis of experimental data. The analysis of experimental data on surface tension and contact angle at the oil–water interface and hydrophobic solid–liquid interface also reveals the universal nature of the interaction between ions and hydrophobic interfaces.