Selective solvation in aqueous mixtures: Interface deformations and instability

Abstract

We briefly review the effects of selective solvation of ions in aqueous mixtures, where the ion densities and the composition fluctuations are strongly coupled. We then examine the surface tension γof a liquid-liquid interface in the presence of ions. We show that γcan be decreased drastically due to the electrostatic and solvation interactions near the interface. We calculate how the free energy is changed due to small surface undulations in the presence of an electric double layer. A surface instability occurs for negative γ, which can easily be realized for antagonistic ion pairs near the solvent criticality. Three-dimensional simulation shows how the surface instability is induced.

16 pages, 4 figures

References in corpus (4)

• Surface tension of electrolytes: Hydrophilic and hydrophobic ions near an interface
• Surface tensions and surface potentials of acid solutions
• Charged colloids in an aqueous mixture with a salt
• Nonionic and ionic surfactants at an interface

Cited by in corpus (1)

• Structure Formation due to Antagonistic Salts