IR spectroelectrochemical investigations of solvent roles in deactivation of poly(3-methylthiophene) films

IR spectroelectrochemistry is employed to study deactivation of poly(3-methylthiophene) films in the solvents of acetonitrile, nitromethane and propylene carbonate. Influences of-various concentrations of water on deactivation of the polymers are also investigated in acetonitrile solutions. Water accelerates the deactivation of the polymers due to its nucleophilic substitution at the aromatic rings. Spectra exhibit less changes associated with the film structure so that the polymers are more stable in the solvents of nitromethane and propylene carbonate than in acetonitrile which possesses the largest pK(a) value. Some possible mechanisms are presented in this paper on the basis of the spectrum analyses. (C) 1997 Elsevier Science Ltd.