Materials Science Forum Vols. 510-511

Abstract: Formation of coatings with combined properties of being superhydrophilic / superhydrophobic is of immense applications in the field of optics. In our present work, we developed a hydrophilic, antifogging, transparent, and stable coating by employing an anionic electrolyte, Tiron and dip-coating of organic-inorganic mixture. One of the attempts was to adhere Tiron on metal oxide surface by chelating effect, and the other one was to apply an organicinorganic coating on glass or lens substrate. The latter was formulated by mixing appropriate ratios of organic silanol coupling agents and diacrylates component for strong adhesion to the substrate, and inorganic component of a hybrid mixture of silica, titania and Tiron for the antifogging behavior. The surface chemistry of the coated films was studied by taking ATR-IR measurements, and the wetting behavior was characterised by contact angle measurement

Abstract: Crystalline TiO2 particles with a diameter of 300nm were obtained from aqueous TiOCl2 solution with 0.67M Ti4+ concentration, diluted by TiCl4 solution using the homogeneous spontaneous precipitation process. Dispersion stability of rutile TiO2 powder with acicular typed primary particles has been investigated in both aqueous and organic media. In this paper, we focus on the TiO2 suspension stability in aqueous and organic media using a recently developed optical analyzer(Turbiscan) and Zeta potential analyzer. The surface potentials of TiO2 particles were greatly modified by dispersion medium and valance of the ionic species, which governs the colloidal behavior of TiO2 particles virtually.

Abstract: The lithium ionic conductivity of Poly (acrylonitrile) (PAN) gel polymer electrolyte with PC/EC was found to be about 1.3 x 10-3S/cm at room temperature. The discharge curve of Li/ PAN (PC+EC)/S battery showed only one plateau region, which is different from that using PVdF(TEGDME) gel polymer electrolyte. Also, the first discharge capacity was 556mAh/g-sulfur in Li/S battery using PAN (PC+EC) gel electrolyte at room temperature.

Abstract: Transparent TiO2, WO3-TiO2, and MoO3-TiO2 films were prepared by spin-coating each colloidal suspension. The monolayer coverage of WO3 on the surface of TiO2 greatly increased the photocatalytic activity in the decomposition of gaseous 2-propanol, whereas the addition of MoO3 considerably decreased the photocatalytic reaction of TiO2. For the estimation of superhydrophilicity, the change of contact angles between the water drop and the film surface was measured as a function of UV-irradiation time. The measured contact angle of WO3-TiO2 film was considerably lower than that of TiO2 before the UV-irradiation, and it decreased to the minimum value about 4 times faster than that of pure TiO2 films with the irradiation of UV light. On the other hand, MoO3-TiO2 films showed a low contact angle at initial point, but their contact angle was very slowly decreased under the UV light. The initial low contact angles suggest the high hydrophilic character of WO3-TiO2 and MoO3-TiO2 films with high Lewis surface acidities. The observed trend suggests that the superhydrophilicity is closely related to the photocatalytic activity.

Abstract: Hexagonal and cubic mesoporous TiO2 films were prepared by using triblock copolymer-templated sol-gel method via evaporation-induced self-assembly (EISA) process. The mesophase of TiO2 film was controlled by spin-speed during the spin-coating process. The hexagonal mesoporous structure was formed at a high spin-speed around 2000 rpm, whereas the cubic mesostructure was formed at a low spin-speed around 600 rpm. XRD and TEM results indicate that those mesostructures are highly organized with a pore diameter of 7 nm. The prepared cubic and hexagonal mesoporous films were tested as photocatalysts for the decomposition of 2-propanol in gas phase. Both films presented considerably higher photocatalytic activity than a nonporous TiO2 films prepared by a typical sol-gel process without addition of triblock copolymer. Notably, we found that the cubic mesoporous films showed a relatively higher photocatalytic activity than the hexagonal mesostructured film. We believe this is due to the orientation of pore channels open on the surface of mesoporous films.

Abstract: Adhesion/cohesion is one of the most important properties for coatings. It is related with their durability and functionality of coatings. In this study, a series of TiO2 coatings were prepared by atmosphere plasma spraying under different deposition parameters. Their adhesion or cohesion was evaluated as a function of coating thickness as well as deposition parameters using the scratch test. In addition, the influence of deposition parameters on coating porosity, surface roughness, and microhardness is discussed. The results indicate that the deposition parameters investigated have a remarkable influence on coating porosity and microhardness as well as adhesion or cohesion, but no obvious influence was observed for surface roughness.

Abstract: Carbon nanotubes (CNTs) in a high yield were synthesized by the decomposition of the methane gas with CCVD, in which two different reaction routes of sol-gel method prepared Fe-Mo- Mg-O catalyst. The two different routs influenced the wall number and defects of CNTs and the formation of CNTs. The concentration of Mo in the catalyst played a very important role in the yield of CNTs.

Abstract: The commercial nano-sized TiO2 powder (P25) was immobilized on foamed waste-glass substrates by using the plasma spraying technology. The immobilized TiO2 coatings were applied to treat both the green tide and the red tide under illumination of an UV light. Their photocatalytic characterizations were evaluated as functions of the number of residual algae, transmission as well as pH value with illumination time. It was found that the plasma sprayed nano-TiO2 coatings on foamed waste-glass show a higher photocatalytic activity, which was effective to treat the green tide and the red tide.

Abstract: Titanium based anodes are widely used in chlori-alkali industry. Two kinds of titanium based anodes were characterized by using XRD and SEM. The test results of their electrocatalytic properties showed that the nanosize crystals have great effect on the anode’s polarization behaviors and accelerated stability life. The anode with higher content of Ta possessed a smaller crystal size and better electrocatalys

Abstract: In this paper a series of silver ions-substituted hydroxyapatites (HA) were prepared. The antibacterial activities of these materials on textiles against bacteria have been investigated. Titania (TiO2) was selectively added into the materials to decrease the silver-ions concentration to get the same active antimicrobial effects. The microstructure, the shape and size, concentration of silver, and the groups of the composite materials were characterized using transmission electron microscopy (TEM), infrared spectroscopy (IR), Atomic absorption spectroscopy (AAS), and X-ray diffraction (XRD). The results showed that there was a dose dependent-effect of silver-ions concentration from the disk diffusion test. The higher the silver-ions concentration, the better the antibacterial activity of the composite materials was. Keeping silver-ions concentration constant, the antibacterial activity of the materials for adding Titania was better than that of without Titania. Moreover, the addition of Titania would inhibit the discolouration of the composite materials. The antibacterial activities of the composite materials differentiate to some extent with the bacterial strains.