The Surface Tension of Ionic Liquids

Abstract

Ionic liquids usually form electric double layers, i. e., a local separation between the negative and positive charges, in regions of spatial non-uniformity occuring close to electrodes or to interfaces. The presence of an interfacial electric double layer, at say, the liquid-vapour interface of a molten salt, will modify the expression of the surface tension of that interface. The corresponding modification of the surface tension cannot beobtained from the standard expressions for ordinary liquids, as encountered in textbooks⁽¹, since the latter inmediately lead to divergencies in the presence of the long-ranged Coulomb forces set up by this double layer.