Dimer and rods in the conducting state of polyaniline

In this paper we present a quantitative theory of the insulator-metal transition in the conducting polymer polyaniline. We begin by focusing on a theory for conduction in single strands of the polymer. To this end, we introduce the random dimer model and show that this model is capable of explaining the origin of extended states in single strands of polyailine. We then formulate a more global theory for the conductivity within a granular-rod model. We show how quantitative results can be obtained for 1) the temperature dependence of the conductivity σ=σ₀exp[-( T₀ T) ^{1 2}], 2) the doping dependence of T₀, 3) the anomalous 1/T dependence of the thermoelectric power, as well as 4) the linear increase of the Pauli susceptibity with dopant concentration.