Low Frequency AC Conduction in Polyaniline/Zinc Tungstate (PANI/ZnWO4) Composites.

In the present paper, we report low frequency ac conductivity and dielectric studies on the composites of conducting polyaniline (PANI) with crystalline zinc tungstate (ZnWO4) powder. These composites have been synthesized by single step in situ polymerization technique by placing fine grade powder of ZnWO4 during the polymerization of aniline. The composites thus formed were characterized by FTIR spectra and scanning electron microscopy (SEM), which conforms the presence of ZnWO4 in polyaniline matrix and the formation of the composite. AC conductivity and dielectric response of these composites were investigated in the frequency ranging from 50 Hz to 5 MHz. it was found that the ac conductivity obeyed the power law index, where the ac conductivity increases with frequency. PANI/ZnWO4 composites have shown high dielectric constant, which could be related to conductivity relaxation phenomenon. It is observed that both dielectric constant and dielectric loss have decreased with increase in frequency. Variations in measured parameters of AC response with increase frequency of the composites follow systematic trends that are similar to those observed with decreasing temperature and level of doping. [ABSTRACT FROM AUTHOR]