Simulations of the in situ cyclic voltammetry dependent EPR spectra and DC conductivity

In situ cyclic voltammetry (CV) dependent EPR and DC conductivity of polyaniline have been reported by many groups. However, the variation of the EPR intensities at two half-wave potentials of the CV scan and the asymmetric CV dependent DC conductivity have remained to be fully accounted for. Here we present in detail a novel quasi-random oxidation model and the related simulation results to interpret the reported in situ experimental results. This model quantitatively describes many phenomena and physical properties found in polyaniline including the origin of the defect states, the variations of the in situ EPR signal during CV potential scan, the effects of the hydrolysis, and the pH-dependent DC conductivity data. The statistical nature of this model suggests its general applicability to the oxidation processes of other conducting polymers. The important roles of nearest neighbor Coulomb interaction and formation of a metallic polaron lattice in the computer modeling are evaluated and discussed.