Polyaniline, air stable organic metal: fact, no longer fiction

Via improved chemistry we have increased the maximum attainable conductivity in oriented polyaniline. D.C. conductivityʹs approaching 104 Scm−1 have been measured. Temperature dependent transport measurements reveal that our new polyaniline behaves in a similar fashion to high conductivity polyacetylene and can be modelled in the same way. However we do observe strongly temperature dependent electrical anisotropy below a characteristic temperature of ca. 150 K Thermopower measurements indicate that the system is metallic in the parallel direction but also, we find that the thermopower is anisotropic. Thermopower in the perpendicular direction changes sign at around 200 K. This we take to indicate that the interchain conduction process involves phonons, and henece a different transport mechanism must control it as compared to the metallic intrachain transport.