Dielectrical Properties of PANI/TiO_2 Nanocomposites

摘要

Conducting polyaniline/titanium dioxide (PANI/TiO_2) composites have been succesfully synthesized by insitu polymerization technique. The PANI/TiO_2 nanocomposites of different compositions were prepared by varying weight percentage of TiO_2 nanoparticles such as 10 wt%, 20 wt%, 30 wt%, 40 wt% and 50 wt% into the fixed amount of the aniline monomer. The prepared powder samples were characterized by X-ray diffractometer (XRD) and Scanning electron microscope (SEM). The intensity of diffraction peaks for PANI/TiO_2 composites is lower than that for TiO_2. SEM pictures show that the nanocomposite were prepared in the form of long PANi chains decorated with TiO_2 nanoparticles. The dielectric properties and AC conductivity were studied in the frequency range 1K Hz-10M Hz. At higher frequencies, the composites exhibit almost zero dielectric loss and maximum value of σ_(ac) is found for a concentration of 20 wt% TiO_2 in polyaniline. The interface between polyaniline and TiO_2 plays an important role in yielding a large dielectric constant in nanocomposites.