Electron paramagnetic resonance of poly(benzazole)s and conducting properties of N+-implanted poly(benzazole)s

We present electron paramagnetic resonance (EPR) studies of the magnetic defect in poly(benzazole)s (including poly(p-phenylene benzobisthiazole) (PBZT), poly(p-phenylene benzobisoxazole) (PBO), poly(2,5-benzoxazole) (ABPBO), PBO–ABPBO and poly(1,4-phenylene benzobisoxazole-co-dimethylene benzobisoxazole) (PBO–PBOC2)) and the model compounds. Temperature dependence of the EPR spectra of poly(benzazole)s over the range 100–300 K and the effect of heat-treatment temperature on EPR parameters were also discussed. FeCl3·6H2O-doped PBZT was investigated in its EPR signals. The results of analyses of the detailed lineshapes and linewidths were discussed in terms of the soliton–antisoliton, polaron and bipolaron model of the magnetic defect. After that, the conductivity studies and Raman characterization of N+-implanted PBZT and PBO were reported. The room-temperature conductivity of these implanted polymers, approximately 0.1–10 S cm−1, is significantly higher than that of pristine polymers. It was revealed through Raman spectrum that the conductivity was attributed partially to the graphite laminar formed in the process of ion-implantation. The results of these studies contribute toward an identification of the origin and nature of the paramagnetic centers in poly(benzazole)s and toward an understanding of the charge transport mechanism.