Charge delocalization in poly(o-toluidine) fibers

We report the results of temperature-dependent conductivity σdc(T), thermoelectric power S(T), microwave dielectric constant εmw(T) (f=6.5 GHz) measurements, and x-ray diffraction studies for the camphor-sulfonic-acid-doped poly(o-toluidine) fibers prepared in m-cresol (POT-CSA). Compared to previously studied hydrochloric-acid-doped poly(o-toluidine) samples, POT-CSA fibers show significantly higher σdc with a much weaker T dependence, much larger εmw, and dramatically different temperature dependence of thermoelectric power with S(T)=A+BT, where A<0 and B>0. These results demonstrate the formation of the delocalized electronic state in the poly(o-toluidine) system, despite the asymmetry of the repeat unit.