THE 2-DIMENSIONAL STRUCTURE OF POLYPYRROLE FILMS

An analysis of the XPS core level spectra of polypyrrole films provides evidence that a two-dimensional microscopic structure can be obtained when high current densities are applied during the electropolymerization process. The properties of such films are compared to those of predominantly one-dimensional polypyrrole films prepared at low current densities. The structural differences occurring in the N(1s) core level spectra are related to different partial charges at the nitrogen atoms. These appear only in heterocyclic subunits which are based on 2-3 linked pyrrole monomers, as determined by semi-empirical MNDO calculations. The model calculations allow us to compose a structural model of two-dimensional polypyrrole which is in accordance with the elemental analysis of such films.