Broadband dielectric spectroscopy of conducting polyaniline

Abstract

Dielectric spectroscopy can be used to probe both the conduction and polarisation processes of a wide range of materials. The authors focus on the dielectric properties of conducting polymers over the frequency range 1 Hz to 20 GHz. Initial measurements have been made on polyaniline samples at room temperature. This particular conducting polymer is of interest since it is a mixed conductor (i.e. showing both electronic and ionic transport). Analysis of the frequency dependent complex permittivity can be used to indicate free charge conduction, charge hopping or ionic diffusion. Temperature dependent measurements are required to determine the type of hopping mechanism where such a process is observed. Experimental results can be compared to the range of theoretical models that are available from the literature describing these processes (Nalwa, 1997; Mott and Davies, 1979; and Sheng, 1980).