Dielectric Spectroscopy of Conductive Polyaniline Salt Films

摘要

Dielectric responses of polyaniline (PANI) salt films,made from two different methods,were compared to investigate the effect of a dopant and film-formation methods on the dielectric properties.One of the film-formation methods for emeraldine salt was the film-doping method,and the other,the solution-doping method.The conductivity relaxation and dielectric properties were measured by a microdielectrom-eter at 293 K in the frequency range of 1-100,000 Hz.Dielectric spectra were a function of the dopant in the case of the film-doping method,whereas it was a function of solvent-dopant combinations as well as the dopants in the solution-doping method.The dielectric responses of film-doped samples had similar patterns irrespective of the dopants,while those of solution-doped samjples were varied,probably due to different conjugation conditions or/and the conduction mechanism.In the case of film-doped samples,dielectric loss and permittivity values were increased with decreasing dopant sizes.The dielectric relaxation times were also varied depending on the kind of dopants.The different solvent-dopant combinations led to variation of the dielectric responses in the solution-doped PANI due to an altered chain structure.