Thermodynamic properties of polyelectrolyte solutions. Part 2.—Influence of the polyelectrolyte charge density

Abstract

Thermodynamic properties of polyelectrolyte–simple salt solutions, at widely differing polyelectrolyte charge densities, have been studied by the Donnan equilibrium method. The measurements were carried out with carboxymethylated hydroxyethyl cellulose of various degrees of substitution, in solutions of NaCl and CaCl₂. The measurements over a broad range of experimental conditions substantiated the additivity rule for polyelectrolyte solutions, although deviations from this rule were observed at very low salt concentrations, where the activity of the salt apparently increased. The results are only in qualitative agreement with Manning's theory of polyelectrolyte solutions.