Polycarbonate-Carbon Nanofibers Composites: An Electron Spin Resonance Study

Electron spin resonance investigations on polycarbonate loaded with various amounts of carbon nanofibers (ranging from 0% to 10%) are reported. A complex resonance spectrum was recorded. The spectrum was assigned to the convolution of resonance lines originating from the conducting electrons delocalized over the metallic domains of nanotubes, of free radicals generated during the polymer processing, and of catalyst's traces. The shape of resonance spectra originating from conducting electrons delocalized over the metallic domains of nanotubes was accurately fitted by a Lorentzian-like shape. The correlation between the measured DC resistivity of these samples and the relevant parameters of the resonance spectrum (line width, g-factor, and ratio between the amplitude of the absorption and dispersion components) was investigated. The saturation of the ESR line, at room temperature is reported.