Comparison of electronic transport properties of soluble polypyrrole and soluble polyaniline doped with dodecylbenzene-sulfonic acid

The temperature dependences of the conductivity of soluble polypyrrole (PPy) and soluble polyaniline (PANI) films doped with dodecylbenzene-sulfonic acid (DBSA) have been studied. The room temperature conductivities of samples were 1-8 and 95-100 S/cm, with resistivity ratio rho(t) = rho(20 K)/rho(300 K) similar to 10(4) and rho(r) = rho(1.4 K)/rho(300 K) similar to 32 for PPy-DBSA and PANI-DBSA, respectively. At low temperatures, the temperature dependence follows the sigma(T) = sigma(0)exp[-(T-0/T)(m)] law, which has been explained within the framework of granular metals model (m = 0.5) for PPy-DBSA and Mott's variable range hopping model (m = 0.25) for PANI-DBSA. The magnetoresistance of PANI-DBSA is positive and follows H-2 and H-1/3 dependencies at low and high magnetic fields, respectively; the magnitude of the magnetoresistance is strongly temperature dependent. (C) 1999 Elsevier Science S.A. All rights reserved.