An explicit molecular thermodynamic model for polyelectrolyte solutions

Polyelectrolyte solutions are modeled as linear tangent jointed and charged hard-sphere chains and counterions. Besides coulombic interaction, stickiness between polyions and counterions is taken into account as a short-range non-coulombic perturbation. The solvent is considered as a continuum medium with a certain permittivity. Expressions of thermodynamic properties derived in this work consist of two contributions. The first contribution responsible for the formation of polyion chains from monomers is derived by the statistical association theory that is the same as our previous work. The second contribution accounting for the additional stickiness is obtained by the same method. A molecular thermodynamic model with explicit expressions is then obtained. Thermodynamic properties for polyelectrolyte solutions can be described satisfactorily.