Enhancement of electrical conductivity of uniaxially and biaxially processed poly(p-phenylene sulfide) films

Abstract

A fundamental study of electrical conductivity of uniaxially and biaxially stretched poly-p-phenylene sulfide (PPS) film was conducted. In this paper, we paid special attention to understand the effect of processing conditions on the electrical conductivity as well as the conduction mechanism of tantalum pentafluoride (TaF5) doped PPS. The electrical conductivity of PPS film was measured by a four-point probe method in the parallel and perpendicular directions to the stretching direction. The infrared spectra of doped and undoped stretched PPS films demonstrate that the TaF5 doping causes distortion (polaron) in PPS chain and conduction. A similar discussion was reported by Tsukamoto, et al. (1, 2). They found the delocalization of π-electrons in doped PPS by X-ray spectoscopy (XPS), infrared spectroscopy (IR), and C13-NMR. The conductivity of doped PPS films increased with increasing stretching ratio. The crystallinity effect on the electrical conductivity was investigated by changing crystallinity of PPS films in terms of annealing and multi-axially stretching. Orientation development was investigated by wide angle X-ray scattering and birefringence techniques. The relationship between conductivity and orientation of stretched PPS films was investigated by introducing electrical anisotropy.