الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Titanium oxide (TiO2) were prepared by Sol gel method, and different TiO2/PVA nanocomposite films were prepared using the solution casting method according to the formula with compositions (wt. % between TiO2 and PVA solution concentration: 0%, 1.33 %, 2.6%, 3.9% and 6.6%). X-ray diffraction (XRD), scanning electron microscope (SEM) and Fourier transformer infrared spectroscopy (FTIR) were measured. The XRD reveals the presence of both anatase and rutile TiO2 phases. The average grain size (D) of anatase and rutile TiO2 were found to 63 nm and 27 nm, respectively. The TiO2 nanoparticles formed were highly agglomerated and the average crystal size estimated by micrograph is in range of 21-32 nm which is in closed agreements with the crystal size estimated by Scherer’s. The optical properties of TiO2/ PVA composite films have been investigated. The direct optical band gap is red shifted from 3.87 eV to 2.68 eV with the increase of TiO2 content. Also, the electrical conductivity data were analyzed in the light of the models of polaronic hopping conduction. The analysis shows that the high-temperature conductivity is well explained by polaronic models. While at intermediate temperature the Greaves VRH (variable-range hopping) model was found to be appropriate.