Dielectric behavior and AC conductivity of low loaded polyaniline emeraldine base - Biopolymer nanocomposite

摘要

Polyaniline emeraldine base-chitin nanocomposites have been prepared by solution casting technique. Polyaniline self-assembled nanofibers (PANF) with an average diameter of 62nm were synthesized by direct mixed oxidation performed in aqueous hydrochloric acid in the presence of ammonium peroxodisulfate as oxidant. Dedoped polyaniline nanofibers were homogeneously dispersed in the 5% LiCl/ N,N-dimethylacetamide and then mixed with chitin solution made in the 5% LiCl/ N,N-dimethylacetamide solvent system according to predetermined weight ratios. The characterizations of the composites were done by Fourier transform infrared spectroscopy (FTIR), Field Emission Scanning Electron Microscopy (FESEM) and Impedance spectroscopy (100 Hz-10 MHz) at room temperature. The real and imaginary part of dielectric permittivity is observed to decrease with an increase in frequency and explained on the basis of Maxwell-Wanger-Sillars polarization. Frequency-dependent conductivity of prepared composites was found to increase with the increase of frequency because at higher frequency space charge polarization effect decreases and hence the ionic mobility increases.