Frequency-dependent conductivity and dielectric permittivity of emeraldine base and weakly doped poly(o-toluidine)

We report the results on the low frequency dielectric study of pressed pellets of poly(o-toluidine) (POT) in the emeraldine base and weakly doped emeraldine salt forms. The parameter describing the doping defined as y = [Cl-]/[N] was synthesized to be y = 0, y = 0.03 and y = 0.07. We suggest that the presence of polarons and bipolarons is responsible for the dielectric relaxation mechanism as well as the frequency and temperature dependence of conductivity. A broadening in the spectrum of relaxation times of the dielectric relaxation process due to charge motion via creation/annihilation of polarons and bipolarons, and their subsequent diffusion becomes faster as doping increases. (C) 1998 Elsevier Science S.A. All rights reserved.