The metallic state of doped polyacetylene and polypyrrole

A low frequency Drude model is used to analyze the huge negative dielectric constant at microwave frequency for heavily iodine doped stretched and unstretched Tsukamoto polyacetylene and unoriented polypyrrole containing PF6. The relatively small plasma frequencies and anomalously long scattering times of these materials indicate the importance of phonon back scattering of the most delocalized conduction electrons, as expected for the open Fermi surface of a highly anisotropic metal. These results are contrasted with the more localized behaviour of the neck and end portions of stretched polyacetylene and of polypyrrole doped with TsO.