Potential of zero charge for polypyrrole

The surface tension (γsl) of polypyrrole against the aqueous electrolyte solution was measured by in-situ electrochemical Wilhelmyʹs plate method. The maximum of the surface tension was observed close to the redox potential (Ep) of polypyrrole, which was attributed to the surface excess charge and the polar contribution of polymer due to the ionic character of doped polypyrrole. This phenomenon was discussed in relation with the electrochemical redox behavior of polypyrrole and the potential of zero charge (PZC) of polypyrrole.