An electromechanical model for the electrochemical oxidation of conducting polymers

Chronoamperometric responses associated with doping processes in conducting polymers have been simulated from the combination of mechanical relaxation models and electric circuits. Slow opening of the polymeric entanglement due to the entrance of solvated counterions and repulsion between charged chains has been correlated to the mechanical strain during stress relaxation in a Voight-Kelvin element. Overall charge involved in polymer oxidation can be decomposed into two components: a capacitive contribution (Qcap) related to the charging process of the electrical double layers after the potential step and a faradaic charge (Qfar) responsible for the appearance of positive charges along polymeric chains. The electrical resistance for this last process is caused by both diffusional and time-dependent relaxational impediments.