Dynamic mechanical behaviour of electrochemically synthesized polypyrrole films

Dynamical mechanical spectrometry experiments were performed on polypyrrole films to provide some information on the microstructure through the analysis of the molecular motions in the material. Various polypyrroles doped with different aromatic anions (benzene sulfonate, p-toluene sulfonate, 2-naphthalene sulfonate and anthraquinone-2 sulfonate) have been analysed in the − 150 to 250 °C temperature range. Two mechanical relaxations have been detected. A low-temperature relaxation, located at about − 60 °C at 1 Hz for all the analysed films, is due to the motion of water molecules sorbed in the polymer. The second relaxation is located at a higher temperature between 118 and 214 °C according to the nature of the dopant. It could result from polymer backbone motions. It has been related to the polypyrrole glass transition.