Abstract
Expansion and contraction in regioregular and regiorandom poly(3-alkylthiophene), PAT films (alkyl=hexyl and dodecyl) upon electrochemical oxidation and reduction in organic electrolyte solvents are studied. It is found that the deformed films consist of two components, which respond to electrochemical cycle and creeping. The PAT films with short alkyl chain length show relatively large deformation by the electrochemical cycle, because of the higher density of electroactive π-electron components. The expansion/contraction ratio of PAT films is discussed taking the morphology into consideration and comparing it with the results for the other conducting polymers of polyaniline and polypyrrole films.