Composite nanofibers composed of organic polymer and inorganic nanomaterials have huge potential to be used in different industrial applications. However, the main concern on the use of composite nanofibers is the distribution properties of nanomaterials in the polymeric matrix. The effect of the capillary tip charge on the additive distribution in the electrospun nanofiber has been previously studied and can be found in the literature. In this study, focus is placed on the investigation of TiO2 nanoparticles (TiO2 NPs) distribution in the polysulfone (PSF) nanofiber. X-ray Photoelectron Spectroscopy (XPS) was conducted to measure the percentage of TiO2 on the surface of the prepared PSF/TiO2 composite nanofiber. The results showed that there was no TiO2 NPs on the surface of the nanofiber for up to 10 nm in depth. TiO2 nanoparticles were mainly found in the center of the nanofiber due to the accumulation of the hydrophobic PSF at the surface of the composite nanofiber. The findings of this work can provide better interpretation of the impact of the interfacial tension on the distribution of the inorganic nanomaterials in the electrospun nanofiber.

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.

In this study, titanium dioxide nanoparticles were used for the removal of sulfate ions. The initial properties of the nanoparticles before and after sulfate adsorption were examined using instrumental techniques. The effects of parameters such as concentration, pH, time, and temperature on sulfate removal were measured, and the optimal conditions for each parameter were applied in the adsorption isotherm. The calculation of thermodynamic constants revealed a negative ΔG° (free energy of gypsum), indicating a spontaneous reaction that does not require energy input. The ΔH° (enthalpy) of the reaction was positive, suggesting an endothermic nature of the removal process, while the positive ΔS° (entropy) indicated an increase in disorder during the reaction. The Freundlich and Langmuir isotherm models were fitted to the experimental data under optimal conditions, with the Langmuir isotherm equation providing a better fit with an R2 value of 0.994. EDX analysis confirmed that the titanium dioxide nanoparticles primarily consisted of titanium and oxygen before sulfate adsorption, while sulfur was observed after adsorption, indicating surface adsorption of sulfate. Furthermore, the maximum adsorption capacity of titanium dioxide nanoparticles for sulfate was calculated as 10.24 mg/g based on the Langmuir equation. By comparing this adsorbent with others, it can be concluded that these nanoparticles are effective in sulfate removal from water.

Synthesis of chemical compounds using materials which are compatible with environment, non-toxic and safe, is one of the principles of green chemistry. In this paper, all principles of green chemistry with two new methods for green synthesis of titanium dioxide nanoparticles have collected. Titanium dioxide is a photo catalyst which has various applications especially in green chemistry. This paper is about synthesis of TiO2 nanoparticles first by using Nyctanthes Arbor-Tristis leaves extract and then by a bacteria called Planomicrobium sp. Then the size and morphology of the synthesized nanoparticles by two methods are compared by their scanning electron microscopic (SEM) images.

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.

In this work structural defects were created in P25-TiO2 nanoparticles by using hydrogen DC plasma treatment in different temperatures and exposure times. X-Ray diffraction measurements show that the structure of TiO2 remains unchanged after hydrogenation. Diffuse reflectance spectroscopy measurements demonstrated that the band gap of TiO2 was not changed considerably by the hydrogenation. However, by applying the hydrogen plasma for 40 min at a temperature of 350 ° C, photocatalytic activity of TiO2 nanoparticles enhances. No more change was observed in the photocatalytic activity of the samples with plasma exposure time more than 40 min. Photoluminescence analysis shows the sample prepared at 350 ° C has a large amount of defects created by the plasma treatment. It seems both, structural defects and hydrogen doping in the samples are important for more efficient photocatalytic behavior of TiO2 nanoparticles. PACS: 82. 45. Jn, 61. 46.-w, 61. 72.-y, 78. 55.-m.