Potentiometric Titration of Polyelectrolytes

Abstract

An experimental study is carried out on the potentiometric titration of the poly (vinyl alcohol) partially acetalized with glyoxylic acid. It reveals that the titration curve of the polyacid with fairly large dissociation constant is better fitted by the relation proposed firstly by Pals and Hermans than by Katchalsky's equation. The radius of this polyacid in solution is estimated from the electrostatic free energy change so obtained, by the use of our theoretical treatment of polyelectrolyte solutions: the size is found to have the tendency of decreasing sharply with polymer concentration. The radical discrepancy between electrophoretic and potentiometric potentials is also discussed.