STRUCTURAL AND FREQUENCY DEPENDENT DIELECTRIC PROPERTIES OF ZnO NANOPARTICLES AND PANI / ZnO NANOCOMPOSITE BY MICROWAVE-ASSISTED SOLUTION METHOD.

Zinc Oxide nanoparticles were synthesized by microwave assisted hydrothermal method using Zinc Nitrate Hexahydrate (ZnNO3.6H2O) as a starting material. Polyaniline / Zinc Oxide (PANI/ZnO) nanocomposite material was prepared by an in-situ polymerization of aniline in the presence of as-synthesized ZnO nanoparticles. The structure, morphology and functional group of the synthesized Zinc Oxide nanoparticles and PANI / ZnO nanocomposites were characterized by X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR). The sharp peaks in the X-ray diffraction pattern indicate that the obtained powder was ZnO and was crystalline in nature. The crystallite size of the sample were calculated from the full width at half maximum of X-Ray diffraction peaks by using Debye-Scherrer formula and were found to be 45nm. The absorption peaks in FTIR spectra of PANI / ZnO nanocomposites were slightly shifted to higher wave number than that of pure ZnO, which confirms that there was a strong interaction between polyaniline and Zinc Oxide nanoparticles. The TEM images revealed the uniform distribution of the ZnO nanoparticles in the PANI matrix. Dielectric studies of ZnO nanoparticles show the frequency dependent dielectric behaviour of ZnO nanoparticles. Results reveals that the dielectric constant decrease with the increasing frequency whereas the a.c conductivity of the sample increases with the increase in frequency.