Electrical transport crossovers and thermopower in doped polyaniline conducting polymer

We report on both the electrical and thermoelectric transport properties as a function of temperature in polyaniline doped with camphor sulfonic acid (CSA) for a wide range of CSA doping. A transport crossovers diagram illustrating metallic and insulating like behaviors is proposed and seems to result from the interplay between charge doping and disorder. In particular, the one half doping not only leads to an optimal electrical conductivity reaching 120 S/cm at 300 K but also the lowest thermopower slope. The measured thermopower appears closely related to the metallic onset in agreement with a metallic origin of its linear temperature dependence.