Limiting laws and counterion condensation in polyelectrolyte solutions. V. Further development of the chemical model.

Counterion binding to polyelectrolyte chains is formulated as a chemical reaction Mz (free) leads to Mz (bound). Expressions for the chemical potentials of free and bound counterions are set equal to obtain the reaction equilibrium. The results are equivalent to those in the previous paper of this series. An additional result obtained here is that a polyion holds its bound counterion layer with a strength on the order of 100 kcal/(mole cooperative unit). The method is then applied to the calculation of the polarizability along the chain due to the bound (condensed) counterions.