Thermally enhanced conformational relaxation during electrochemical oxidation of polypyrrole

Oxidation of polypyrrole which was previously prepolarized at highly negative potentials is limited by the ability of polymeric chains to undergo conformational changes. As is well known, polymeric chains can vary their conformational state only when some energetic requirements are fulfilled. This allows the study of how conformational relaxation processes associated with electrochemical doping in conducting polymers are affected by changes in the experimental conditions used. In this work, the influence of temperature on the rate of conformational relaxation in polypyrrole is evaluated, on the basis of our electrochemical relaxation model. The comparison between experimental data and theoretical predictions from the model allows the activation energy ΔH* for the conformational changes associated with polypyrrole doping to be obtained, together with the evolution of structural and electrochemical features of the polymer with the temperature. A new technique of electrochemical thermocurrents is proposed to obtain information about interactions between polymer, solvent and ions.