Linear Charge Density Dependence of the Polyelectrolyte Phase Volume of Ionic Dextran Sulfate as a Strong Acidic Polyion

Research on the counterion binding equilibria of the linear polyelectrolytes with anionic groups, i.e., calboxyl, sulfate, or phosphate group, is important for understanding the effect of the electrostatic interaction on the functionalities of polyions. For the analysis of the counterion binding equilibria of polyelectrolytes, the electrostatic interaction between the counterions and the ionic groups fixed on the polymer skeletons should be quantitatively evaluated. In this research, a “two-phase model” which the formation of a polyelectrolyte phase was assumed around the polymer skeleton was applied. In our previous study, it has been confirmed that the Donnan potential and the polyelectrolyte phase volume of weak acidic polyions can be expressed as a function of the average linear charge distance on the polyions. In this work, the divalent metal ion binding equilibria of dextran sulfate anions of different degree of substitution as typical strong acidic polyions was investigated in order to clarify the ...