Counterion condensation as saturation effect under the influence of ion hydration

Polyelectrolyte solutions are often described by structural theories. These theories in some cases yield values for the counterion concentration at th e charged monomer surface that exceed the saturation concentration. This me ans a change of the ion properties due to ion immobilization or ion condens ation in close vicinity to the polymer ch:lin. The extent of this counterio n condensation (CIC) and the respective surface potential are calculated fr om the saturation concentrations of the electrolyte involved including the influence of ion hydration on the effective dielectric number. In this pape r, we shall consider all these influences by a fundamental differential equ ation and a set of explicit formulae yielding quantitative expressions with out linearization, All calculations are based on the abstraction of an idea lized elementary cell. (C) 2001 Elsevier Science B.V. All rights reserved.