Conformational energy from the oxidation kinetics of poly(3,4-ethylenedioxythiophene) films

Electroactive poly(3,4-ethylenedioxythiophene) perchlorate films shrink and pack by electrochemical reduction at high cathodic potentials. Any subsequent oxidation by potential step gives chronoamperograms showing a maximum. At the maxima the electroactive oxidation reaction occurs under chemical kinetic control. Rate coefficients and activation energies for the reaction can be obtained by applying chemical kinetics methodology. Both parameters present two ranges as a function of the cathodic potential of pre-polarization that defines the initial oxidation state of conformational packing. The activation energy includes two components: the constant chemical activation energy and the conformational packing energy that increases linearly after reduction-shrinking-packing at rising cathodic overpotentials. This methodology opens a way to quantify the conformational energy of polymer chains: the energy used by molecular motors constituting the actuator films of conducting polymers. (C) 2010 Society of Chemical Industry