Dynamics of regioregular conducting polymer electrodes in response to electrochemical stimuli.

We report thickness shear mode resonator acoustic wave data for films of regioregular poly(3-hexylthiophene) films exposed to acetonitrile solutions of LiClO4. Both the current- and acoustic wave-responses to constant (or slowly swept) potential show different regimes, whose characteristics, which are quite different to those of regiorandom electropolymerized films, can be interpreted in terms of crystalline and non-crystalline material. Oxidation of crystalline material, which occurs at low potentials, is dominated by anion transfer; as a result of the associated electrostatic effects, the film stiffens.