Polyfuran films have been synthesized by electropolymerization of terfuran and investigated as a function of film preparation conditions in both the doped and undoped state. These films have been characterized by infrared spectroscopy, scanning electron microscopy, optical absorption, X-ray photoelectron spectroscopy, dc conductivity, and electron spin resonance measurements. The electrolyte anion (dopant) used for the preparation of these films heavily influences the -conjugated system of the polymer backbone. Structural disorder and doping level depends on the nature of the electrolyte anion. CF3SO3-was found to be the best dopant and to cause the least structural disorder or furan ring opening. Electrical conductivities as high as 2 X 10-3 S/cm were obtained in the CFsSOs'-doped state. The temperature dependence of the electrical conductivity indicates a thermally activated process with semiconductorlike behavior. The charge transport properties are explained in terms of polaron and bipolaron states. The polymer band gap was measured at 2.35 eV.

The magnetic properties of γ-Fe2O3 ferrimagnetic nanoparticles embedded in a multiblock poly(ether-ester) copolymer have been investigated by static magnetization and ferromagnetic resonance (FMR) measurements at two different dispersion states. Significant variation of the magnetic response is identified below T≈120K, most pronounced in the marked resonance field shift of the FMR spectra, independently of the dispersion state of the nanocomposites. This behavior correlates favorably with the dynamic relaxation of the copolymer, indicating a matrix freezing effect that is attributed to the magnetoelastic coupling of the oxide nanoparticles with the surrounding polymer. At low temperatures, the dc magnetization and FMR measurements vary considerably for the two nanocomposites, indicating essential differences in their ground state, related to the different morphology of the samples and the concomitant variation of interparticle interactions.

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Sulfur doped graphite is obtained by arc vaporization of graphite rods in the presence of thiophenes. The surfaces of the carbon rods become coated with a layer of a sulfur-doped carbon. X-ray diffraction indicates a small d spacing expansion, and there is a slight decrease in the electrical conductivity of the doped layer. X-ray photoelectron spectroscopy confirms that sulfur incorporation has occurred at a level of 0.6% and that the sulfur atoms are in a neutral state. X-ray photoemission results indicate that S incorporation induces a shift of the valence band toward the Fermi level.

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