High dielectric permittivity in silica-polyaniline nanocomposites

Complex impedance and dielectric permittivity of wide band gap silica-conducting polyaniline nanocomposite have been investigated as a function of frequency and temperature at different compositions. Grain and grain boundary contributions are observed in impedance spectra. The results are interpreted in terms of two series connected equivalent circuit. The large dielectric permittivity similar to 7500 is found. Large value of permittivity is well described by Maxwell-Wagner polarization. Broad and asymmetric dielectric spectra are analyzed by Havriliak-Negami relaxation function.