Modeling and simulation of polyaniline derivatives

Semi-empirical calculations were performed on both the unsubstituted and a series of ring-substituted polyaniline base (pani) model compounds containing two imine (-N =) and amine (-NH-) nitrogens representing one repeat unit of pani base polymers. These calculations show very little change in the computed dihedral angles for the substituted compounds relative to the unsubstituted pani base model compound. The results provide support for the idea that conjugation along the pani chain is not significantly reduced upon ring substitution. It seems that a more important effect of ring substitution involves an increase in interchain separation as a result of the substituents acting as spacers with increased steric repulsion preventing efficient interchain interactions. These results, although obtained on the non-doped pani base, allows the inference with caution that the interchain distance, more so than the extent of intrachain conjugation, may determine the conductivity of substituted pani compounds.