Textural, structural and electrical properties of TiO₂ nanoparticles using Brij 35 and P123 as surfactants

The effect of the use of the triblock copolymer Pluronic P123[(PEO)₂₀(PPO)₇₀(PEO)₂₀, Aldrich] and the non-ionic polyoxyethylene-lauryl ether Brij 35 as surfactants on the textural, structural and electrical properties of nanosized TiO₂ is analyzed in this work. The as-obtained samples were thermally treated at 400 °C to eliminate the surfactant, promote dehydroxylation and crystallize the sample. The TiO₂ samples were characterized by thermal analysis, N₂ physisorption, x-ray diffraction analysis, micro-Raman spectroscopy and scanning electron microscopy. To evaluate the TiO₂ electrical features, I-V data were obtained. The x-ray diffraction results show that in the chemical synthesis using surfactants, the crystallite size is smaller than that of the commercial sample. The Raman spectroscopy results clearly indicate that, when P123 is used, the anatase phase of TiO₂ is obtained, whereas when Brij 35 is used a mixture of the anatase and brookite phases is obtained. The specific surface area and crystallite size of the TiO₂ prepared as indicated above are higher and smaller, respectively, than the corresponding properties found in commercial TiO₂. The I-V plot showed a nonlinear behavior of the nanosized TiO₂. The samples obtained with P123 showed the best electrical conductivity.