ELECTROPLASTIC BEHAVIOR OF DOPED POLY(3-HEXYLTHIOPHENE)

Dynamic viscoelasticity of poly(3-hexylthiophene) (P3HT) doped with io dine or FeCl3 under the influence of electric fields was studied. The doped P3HTs underwent a large decrease in elastic modulus under small electric fields on the order of 1 dc V/mm. The electric fields enhance d the loss tangent. The glass transition temperature decreased as the intensity of the applied fields was increased. This electroplastic beh avior was observed also in ac excitation of less than 1 kHz. Tt was de tected in both crystalline and amorphous P3HTs. Joule heating was a ma in process in the electroplastic behavior of doped P3HTs. We measured FTIR and X-ray diffraction spectra under electric fields to examine th e possibility of other processes. The X-ray diffraction analysis sugge sted a possibility of another process caused by the formation of intra -planar packing of thiophene rings. (C) 1996 John Wiley & Sons, Inc.