Anisotropic Electric Conductivity and Light Transmittance of Polypyrrole/Poly(vinylidene fluoride) Composites Film by Polymerization in Craze

Pyrrole was impregnated and polymerized in the voids of the regular crazes that were generated in poly(vinylidene fluoride) (PVDF) film by the unique crazing process. The spontaneous cyclic process of the stress concentration and releasing generated the periodical craze layers. The composites films were formed by the conductive layers of polypyrrole(PPy) and the insulator layers of PVDF, alternatively. Anisotropic electric conductivity about three orders of magnitude between the thickness or perpendicular direction and the parallel direction to the processing direction was investigated. Black PPy layers absorbed all of the incident light from the tilted angle and PVDF layers transmitted the incident light from the normal angle. Anisotropic transparency that provides the black-colored composites film from tilted viewpoint and the transparent film from the normal viewpoint was observed (View field selectivity).