Dielectric and optical properties of PVA/PAN doped TiO2NPs

Titanium dioxide nanoparticles (TiO(2)NPs) were prepared by sol-gel method. The effect of TiO(2)NPs on structure, dielectric and optical properties of PVA/PAN films was reported. The X-ray diffraction (XRD) and high resolution scanning electron microscopy (HR-SEM) it were used to characterize the prepared samples. The XRD result shows the phase formation of TiO(2)as anatase, with average crystal size of about 50 nm. PVA/PAN-TiO(2)nanocomposite films have an amorphous nature. In addition, the dielectric constant epsilon ', the electric modulusM '' and the ac conductivity (sigma(ac)) were studied also. It was found that epsilon ' increases with temperature, dielectric relaxation observed by electric modulusM '', which may be associated with Micro-Brownian motion of the main PVA/PAN chains. The ac conductivity supports hopping mechanism for the nanocomposite films. The optical investigations show that, increasing TiO(2)content of the samples results in a decrease of the optical band gap accompanied with an increase of the refractive index and electric susceptibility of the nanocomposite films