Integral equation theory for associating liquids: highly asymmetric electrolytes

Abstract

The associating liquids formalism of Wertheim is used to study association in highly asymmetric model electrolytes, with charge asymmetry +1 : –10, +1 : –20 and size asymmetry 1 : 13 and 1 : 8. These models are designed to capture some features of ionic colloids, micelles and proteins, but fall short of a complete description. Explicit predictions are made for the fraction of associated species in the electrolyte. The theory yields improved agreement with structural data from existing computer simulations. Moreover, it predicts correctly that a large fraction of the large, highly charged ions are associated. However, the current level of theory is not a complete description of association.