Spectroscopic analysis of ion-irradiated poly(phenylene sulphide)

Abstract Films of poly(phenylene sulphide) have been irradiated with high energy ions to produce electrically conductive materials. The ions used have been 323 keV Li, 5.6 MeV F, and 50 MeV I. Conductivities between 5.7 × 10 −5 S cm −1 and 0.7 S cm −1 have been observed depending on irradiation conditions. The irradiated polymers have been characterized by infra-red and e.p.r. spectroscopy as well as differential scanning calorimetry (d.s.c.), X-ray diffraction, and scanning electron microscopy. Specular reflectance infrared spectra show the creation of free carriers at higher doses corresponding to increased conductivity. E.p.r. spectra show the existence of free radicals in irradiated films with the concentration generally increasing with dose (up to 4.3 × 10 14 ions/cm 2 ). Because the irradiated layers are much thinner than the complete film samples in these experiments, the differential scanning calorimetry and X-ray diffraction results include contributions from both irradiated and unirradiated regions. Although the d.s.c. suggests increased crystallinity in the irradiated material, X-ray diffraction shows only amorphous material. Possible explanations are discussed. Scanning electron microscopy shows evidence of gas evolution during irradiation.