Transport mechanisms in poly(methyl methacrylate)-β-naphthalene sulphonic acid doped polyaniline blends in acid doped polyaniline blends

Abstract

The transport properties of conductive blends consisting of poly(methyl methacrylate) (PMMA) and polyaniline doped with β-naphthalene sulphonic acid (PANI-NSA) have been studied in the temperature range 80-300 K and in the frequency range 200 Hz to 10 MHz. Percolation behaviour is observed with a percolation threshold f _p = 0·095 wt-% of PANI-NSA content. The temperature dependence of conductivity follows the variable range hopping model. The variable range hopping exponent γ decreases from 2/3 to 1/4 with increasing concentration of conducting polymer in the blend. The frequency dependence of conductivity satisfies the power law σ(ω) ∝ ω^s, with s = 0·75–0·90. The temperature dependence of s indicates that the ac conductivity arises from correlated barrier hopping.