DEPENDENCE OF ELECTRICAL-CONDUCTIVITY ON FILM THICKNESS IN POLYACETYLENE - EFFECTS OF MECHANICALLY FORCED PARALLEL AND INPLANE ALIGNMENTS OF FIBRILS

We have presented conventional analytical formulae which correlate the electrical conductivity of polyacetylene film with its macroscopic morphology represented by mechanically forced fibril alignment (parallel alignment) and in-plane alignment. Through numerical evaluations based on the present analytical formulae, we have clarified that the in-plane alignment contributes to enhance the parallel conductivity of the film in a cooperative manner with the parallel alignment. In particular, the in-plane alignment becomes crucially dominant when the film thickness is less than 1.0 mum, irrespective of whether the film is as-grown or mechanically stretched. On the other hand, although the parallel alignment expectedly decreases the conductivity perpendicular to the elongation direction along with the mechanical stretching, the decrease is partly compensated by an increase due to the in-plane alignment.