In this study, to improve the nanoparticle dispersion and increasing possible interaction between nanoparticle and polymeric matrix in the UP/TiO2 nanocomposite, the surface of the TiO2 nanoparticles was modified in the new approach; first the surface of TiO2 nanoparticles was modified by a coupling agent as 3-(methacryloxy) propyl trimethoxy silane and then polymerized in the presence of ethyl acrylate and methyl methacrylate monomers with AIBN as initiator. FTIR spectroscopy confirmed the presence of the coupling molecule and consequently copolymer macromolecular chains on the surface of TiO2 nanoparticles. Transmission electron microscopy (TEM) was used to study the morphology of the particles before and after the surface grafting. Mechanical properties and ultraviolet visible (UV/Vis) spectroscopy of various samples, including the doubly modified-TiO2 nanoparticles and the unmodified-TiO2 nanoparticles were also investigated. The results showed that surface remodification of TiO2 nanoparticles improve nanoparticles dispersion, mechanical properties and UV protection of the UP/TiO2 nanocomposite.

Nano photo-catalyst coatings, exposed to high-energy photons, have the ability to remove toxic organic compounds from gaseous and aqueous environments. But these coatings, due to lower surface area, are less efficient than nanoparticles. Microstructure of these coatings should be modified in order to improve their efficiency. In this study, nanostructured TiO2/Al2O3 heterogeneous films were synthesized by the sol-gel method. Quartz sheets were used as the substrates, and Al2O3 and TiO2 sols were, in turn, deposited on these substrates by the spin coating method, respectively. The deposited layers were sintered at 800oC and 500oC, respectively. Crystallization of gamma-alumina and anatase phases was confirmed by X-ray diffraction (XRD). The average crystallite size of the anatase films was measured to be about 30 nm by using scanning electron microscopy (SEM). UV-vis absorption spectroscopy was used to calculate the energy gap, and based on the measured absorption wavelengths; the total gaps were calculated to be 3.81 eV and 4.47 eV, for TiO2 and TiO2/Al2O3 layers, respectively. The emission spectra obtained by the photoluminescence analysis were used to confirm the oxygen vacancy formation. Our results showed that, by the addition of Al2O3, neutral oxygen vacancies may be thermodynamically stable stabilized in TiO2.

TiO2/SiO2 and V2O5/ TiO2/SiO2 nano photocatalyst have been synthesized by sol-gel method. X-ray diffraction, SEM, FT-IR, and UV-VIS methods were used to characterize the structures and properties of these photo catalysts. The particle size was determined to be 7 nm using the Scheerer,s equation. The results of XRD and FT-IR confirmed the existence of V2O5, TiO2 and SiO2. In order to investigate and compare the photocatalytic activity of TiO2/SiO2 and V2O5/TiO2/SiO2, photodegradation of monochlorobenzene and dichlorobenzene in water under the ultraviolet and visible lights was studied. The decrease in concentration of monochlorobenzene and dichlorobenzene was monitored by UV-vis spectroscopy. Our results show that in the visible light, the V2O5/ TiO2/SiO2 have better photocatalytic activity in comparison with the TiO2/SiO2.

There are numerous applications of nanomaterials in catalysis, biosensing, biotechnology, electronics, magnetic fluids, energy storage and also in the biomedical field, especially in gene or drug delivery and diagnostics. Nanomaterials have amazing capabilities to stimulate neu ronal cells toward neuronal cell proliferation, neuronal cell adhesion, axonal growth, and neuroprotection. Researchers have demonstrated that nanomaterials can also differentiate stem cells into neuronal cells. Recently, the impact of nanomaterials on the proliferation and differentiation of normal, cancer, and stem cells have been investigated greatly. In this study, the effects of titanium dioxide nanoparticles (TiO2NPs) on the differentiation of neural stem cells are examined. Our findings indicate that TiO2 nanoparticles lead to differentiation tendencies biased towards neurons from neural stem cells, suggesting TiO2 nanoparticles might be a beneficial inducer for neuronal differentiation. We found that pheochromocytoma cell line (PC12 cells) exposed to TiO2, Au/TiO2, Ag/TiO2 nanoparticles significantly increased the differentiation of neural stem cells and promoted neurite outgrowth. Our data may have resulted from the stimulation of cell adhesion molecules that are associated with cell-matrix interactions through nanoparticle. The findings of this work proposes the use of the Ag/TiO2 nanoparticles which also have antibacterial and antioxidant characteristics, as a suitable method to improve Nerve Growth Factor (NGF) activity and efficacy, thus, opening the novel window for substantial neuronal repair therapeutics.

Structural properties and chemical composition change the photocatalytic activity in TiO2-SiO2 nanopowder composite. The SiO2-TiO2 nanostructure is synthesized based on sol-gel method.The nanoparticles are characterized by x-ray fluorescents (XRF), xray diffraction (XRD), tunneling electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), UV-vis.Spectrophotometer and furrier transmission create infrared absorption (FTIR) techniques. The rate constant k for the degradation of methylen blue in its aqueous solution under UV irradiation is determined as a measure of photocatalytic activity.Dependence between photocatalytic activity and SiO2 content in the composite is determined. Rate constant k is found dependent on the content of SiO2 in the composite that calcined at 900oC. The addition of low composition SiO2 to the TiO2 matrix (lower than 45%) enhances the photocatalytic activity due to thermal stability and increasing in the surface area. The effects of chemical compositions on the surface topography and the crystallization of phases are studied.

With various features such as strong oxidation, biocompatibility and acceptable mechanical properties, titanium dioxide (TiO2) is among the materials that are frequently used in biological and medical applications. Nowadays, with the aim of increasing the efficiency of titanium dioxide and practical use of this material, doping it with elements such as silver, zinc and iron has been favored. In this study, Ag-TiO2 and ZnO-TiO2 nanoparticles were prepared by the sol-gel method and were evaluated and compared. In order to identify the present phases in the structure, X-ray diffraction analysis was used. Also for the characterization of the nanoparticles, Ultraviolet-visible spectroscopy (UV-Vis), Energy-dispersive X-ray spectroscopy (EDS), Field Emission Scanning Electron Microscope (FESEM) and Zeta Potential were used. Inaddition, the antibacterial activities of nanoparticles were investigated and compared. The results showed that sol-gel method could successfully produce nanoparticles of Ag-TiO2 and ZnO-TiO2 with the expected combination. The investigation of antibacterial properties of these particles revealed that at lower inhibitory concentrations, Ag-TiO2 composition has a higher antibacterial activity than ZnO-TiO2 one.