Metallic temperature dependence of microscopic electrical conductivity in HCl-doped polyaniline studied by ESR

Microscopic spin and charge dynamics in polyaniline (PANI) are studied by ESR. Temperature dependence of the diffusion rates along a polymer chain D∥ and across chains D⊥ was determined for the emeraldine salt form with HClN≈0.62 and 0.27. The main results are (a) in y = 0.62, D∥ above 150 K follows metallic temperature dependence of T−d with d=2∼3 and an abrupt change in D∥ is found around 150 K, and (b) in both y=0.62 and 0.27, the anisotropy ratio D∥/D⊥ is larger than 103 around 300 K. These results lead us PANI being the highly one dimensional electronic system.