Polyfuran: A New Synthetic Approach and Electronic Properties

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 π-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 × 10⁻³ S/cm were obtained in the CF₃SO₃⁻-doped state. The temperature dependence of the electrical conductivity indicates a thermally activated process with semiconductor-like behavior. The charge transport properties are explained in terms of polaron and bipolaron states. The polymer band gap was measured at 2.35 eV.