Dielectric properties of polypyrrole doped with tosylate anion in the far infrared and microwave

We report measurements of the dielectric behavior in the far infrared (10–200 cm−1) and in the microwave (8.5–12.5 GHz) regime for the conducting polypyrrole (PP) doped with tosylate anion. The dielectric constants have been determined from reflection and transmission data using the Fresnel equations. The magnitude and dispersive nature of the complex index of refraction is described for a number of samples with different levels of conductivity. The ability to tailor the dielectric behavior of these materials has been demonstrated by suitably reducing the oxidized PP films. The high reflectivity in the far infrared and microwave region cannot be accounted for in terms of the Drude model defining metallic behavior. An application exploiting the large real part of the index of refraction and relatively low loss observed in the microwave region is discussed.