Evolution of the electronic states of polyaniline: an ab initio analysis of the orbital states of PAni synthons

In this work, ab initio computations performed using the B3LYP hybrid density functional are applied to describe the full electronic character of polyaniline (PAni) in terms of its logical structural subunits and/or its synthons. A complete description of bonding, redox states, and spectroscopic terms is obtained from this analysis, suggesting that structural and electronic properties of PAni are attributable to its synthons; aniline, p-phenylene diamine, and N,N′-bis(4′-aminophenyl)-1,4-quinonediimine. Though previous modeling attempts with semi-empirical or simple Hartree–Fock methods have provided useful qualitative data, the ab initio/DFT approach used here has been shown to be quantitatively accurate. The general approach to understanding properties of complex materials in terms of its smaller structural units and synthons will be generally useful for polymers and complex clusters.