Electrical properties of polypyrrole doped with β-naphthalenesulfonic acid and polypyrrole-polymethyl methacrylate blends

The electrical conductivity both dc and ac of polypyrrole doped with beta-naphthalenesulfonicacid (NSA) and polypyrrole-polymethyl methacrylate blends have been investigated in the temperature range of 300-80 K and in the frequency range of 100-10 MHz. Samples are prepared by in situ polymerisation technique using the common solvent meta cresol. The frequency dependence of conductivity satisfies the power law, sigma(omega) alpha omega(s), with s = 0.73-0.95. In PPY-NSA, s is independent of temperature and explained by electron tunneling model whereas in PPY(NSA)-PMMA blend s decreases with temperature and the ac mechanism is predicted by the overlapping polaron tunneling. The ac conductivity sigma(omega) as a function of temperature follows the scaling law, sigma(omega)/sigma(0) = 1 + (omega/omega(0))" with n similar or equal to 0.85. (C) 2003 Elsevier Science B.V. All rights reserved.