Conductivity and microwave dielectric response of polyaniline and poly(o-toluidine) fibers

We compare the results of temperature-dependent de conductivity σdc(T) and microwave dielectric constant ϵmw(T) for CSA doped polyaniline (PAN-CSA) and poly(o-toluidine) (POT-CSA) fibers prepared in m-cresol, HCl doped 4-fold stretched polyaniline EB fiber (PAN-HCl(4X)), and HCl doped poly(o-toluidine) (POT-HCl) fibers (unstretched and 3-fold stretched). Although POT-HCl fibers show similar σdc(T) as earlier studied POT-HCl powder, POT-CSA fiber shows significantly higher σdc(T) with much weaker temperature dependence and much larger ϵmw(T), indicating that it is much closer to the localization-delocalization boundary. PAN-HCl(4X) fiber and PAN-CSA fiber have almost identical dc conductivity at room temperature, however PAN-HCl(4X) fiber shows stronger temperature of σdc and a very large positive ϵmw, as opposed to have huge negative ϵmw observed in the PAN-CSA fiber.