Conformational effects on optical charge transfer in the emeraldine base form of polyaniline from electroabsorption measurements and semiempirical calculations

The effects of conformation on optical charge transfer in emeraldine base form of polyaniline were studied using electroabsorption measurements. The experiment was carried out in polymethyl methacrylate matrix at room temperature. The change in dipole moment on excitation and polarizability for electronic transitions was measured. Semiempirical calculations for varying geometries of oligomers were performed. The analysis identified low-energy conformers with large dipole moments caused by conformational heterogeneity.