Ring-torsional solitons in polyaniline.

Abstract

Topological defects involving distortions of the phenyl ring torsion angles in the leucoemeraldine base form of polyaniline are studied. A ring-torsional order parameter is introduced; two solitonlike defects of this order parameter are found, one of which has been discussed previously. These solitons are anticipated to exhibit a conventional spin-charge relationship, unlike the bond-alternation solitons in trans-polyacetylene. The creation energies of these solitons are estimated, and possible experimental signatures and relevance of neutral and charged solitons are discussed.