Combined electrochemical and radiotracer study of anion sorption from aqueous solutions into polypyrrole films

The sorption of SO²⁻₄ and Cl⁻ ions into polypyrrole films has been studied by the radiotracer method under potential cycling and steady state conditions using labelled H₂SO₄ and HCl. Although a potential dependent migration and penetration of anions in the film can be detected, no strong correlation was found between the amount of charge consumed in the oxidation and reduction processes and the number of sorbed anions. The number of positively charged sites attracting anions into the film seems to be significantly lower than that expected from the amount of charge involved in the electrochemical transformations.