Two-Value Hopping and Influences of Disorder in Oxidized Polyaniline

Introducing a two-value hopping, we extended the Ginder-Epstein model to oxidized forms of polyaniline (EB, PNB and chains which present a disordered distribution of quinoid and benzenoid rings). The model reproduced the four and two bands for EB and PNB, respectively. The observed absorptions in the related polymers were explained on the basis of the calculated electronic structures. Disorder in the distribution of the quinoid moities leads to larger band spreading on the energy axis and a reduction of the gaps observed between the different occupied and unoccupied bands. The results showed a disorder-conduction mechanism for polyaniline.