Transport and dielectric properties of α-zirconium phosphate-polyaniline composite

The synthesis of conducting composite involving polyaniline in the layered zirconium hydrogen phosphate, alpha-Zr(HPO4)(2)center dot H2O (alpha-ZrP) and its subsequent characterization and dielectric properties are reported. Aniline monomer is introduced into the interlayer space of alpha-ZrP by adsorption. The encapsulated aniline is polymerized by chemical oxidative method by adding appropriate amount of ammonium peroxodisulphate (APS) solution. X-ray diffraction patterns show that the polyaniline is formed outside alpha-ZrP. The ac conductivity and dielectric properties are extensively studied at low temperature up to the frequency of 5 MHz. The charge transport process is due to electron and polaron tunnelling. The dielectric response exhibit broad spectra which are analyzed by Cole-Cole distribution function. The shape of dielectric spectra and the temperature dependence of relaxation time indicate the relaxor ferroelectric behavior of the composite. The microstructure and electrical transport properties are significantly different from the composite obtained by direct mixing and polymerising of alpha-ZrP and aniline monomer. (c) 2004 Elsevier B.V. All rights reserved.