Hopping conduction on PAni/PSS blends

Conducting blends of polyaniline (PAni) and sulfonated polystyrene (PSS) were obtained by in situ polymerization. We prepared PAni/PSS blends with molar ratio of 1:2 and PSS sulfonated at the degrees of 13, 21 and 30 mol%. The blends were investigated by d.c. conductivity and scanning electron microscopy (SEM). Increasing sulfonation degree increases the conductivity and the miscibility of the blends was observed by SEM. The electrical conductivity of blends was evaluated from 100 to 300 K. We show that three-dimensional variable range hopping is observed. From the hopping parameter we obtained the mean hopping distance, the density of active centers and the energy associated with it. The hopping distance was compared to the mean distance of sulfonic groups of the PSS, indicating that interchain 3D variable range hopping is dominant at low temperatures. (C) 2008 Elsevier B.V. All rights reserved.