Synthesis and dielectric properties of polyaniline/titanium dioxide nanocomposites

Two series of polyaniline–TiO 2 nanocomposite materials were prepared in base form by in situ polymerization of aniline with inorganic fillers using TiO 2 nanoparticles (P25) and TiO 2 colloids (Hombikat), respectively. The effect of particle sizes and contents of TiO 2 materials on their dielectric properties was evaluated. The as-synthesized polyaniline–TiO 2 nanocomposite materials were characterized by transmission electron microscopy (TEM), Fourier transform infrared (FTIR), thermal analysis (DTA/TGA), and X-ray diffraction (XRD). Dielectric properties of polyaniline–TiO 2 nanocomposites in the form of films were measured at 1 KHz–1 MHz and a temperature range of 35–150 °C. Higher dielectric constants and dielectric losses of polyaniline–TiO 2 nanocomposites than those of neat PANI were found. PANI–TiO 2 nanocomposites derived from P25 exhibited higher dielectric constants and losses than those from Hombikat TiO 2 colloids. Electrical conductivity measurements indicate that the conductivity of nanocomposites is increased with TiO 2 content. The dielectric properties and conductivities are considered to be enhanced due to the addition of TiO 2, which might induce the formation of a more efficient network for charge transport in the base polyaniline matrix.