Synthesis and dielectric properties of polyaniline/titanium dioxide nanocomposites

Two series of polyaniline–TiO2 nanocomposite materials were prepared in base form by in situ polymerization of aniline with inorganic fillers using TiO2 nanoparticles (P25) and TiO2 colloids (Hombikat), respectively. The effect of particle sizes and contents of TiO2 materials on their dielectric properties was evaluated. The as-synthesized polyaniline–TiO2 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–TiO2 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–TiO2 nanocomposites than those of neat PANI were found. PANI–TiO2 nanocomposites derived from P25 exhibited higher dielectric constants and losses than those from Hombikat TiO2 colloids. Electrical conductivity measurements indicate that the conductivity of nanocomposites is increased with TiO2 content. The dielectric properties and conductivities are considered to be enhanced due to the addition of TiO2, which might induce the formation of a more efficient network for charge transport in the base polyaniline matrix.