Advanced Materials Research Vols. 79-82

Abstract: Diatomite supported nano-TiO2 composite was prepared by sol-gel method with titanium (Ⅳ) isopropoxide as precursor. The composite was characterized by XRD, SEM and FT-IR. The TiO2 coated on the surface of diatomite was the mixed crystal of anatase and rutile, the average particle size was 11 nm. The photocatalytic activity of composite was larger than that of the Degussa P25-TiO2. The stability of TiO2/diatomite was good and the photocatalytic activity reduced only 12.4% after repetitive-use the catalyst for 15 times.

Abstract: Ferroelectric lead zirconate titanate Pb(Zr0.53Ti0.47)O3 (PZT) nanotubes were prepared using porous anodic aluminum oxide (AAO) template by means of a simple sol-gel method. Scanning electron microscope (SEM) showed that closely packed PZT nanotubes were synthesized with a high pore-filling rate and aspect ratio after annealing at 700 °C. The X-ray diffraction investigations revealed that the annealed PZT nanotubes exhibit a polycrystalline microstructure and were composed of perovskite crystal structure. The results of polarization hysteresis and piezoresponse force microscope (PFM) measurements showed typical piezoelectricity in PZT nanotubes as well as stable electrical properties revealed by leakage current measurement, indicating potential applications using ferroelectric one-dimension nanostructures.

Abstract: Paper reports morphological and humidity sensing studies of WO3 and WO3-ZnO nanocomposite pellets prepared in the weight % ratio of 10:1, 4:1 and 2:1 by solid-state reaction route. The pellets have been annealed at temperatures of 300-500°C. XRD pattern shows peaks of ZnWO4 formed due to solid state reaction between WO3 and ZnO. SEM micrographs show that the sensing elements manifest porous structure. Granulation and tendency to agglomerate seen in the SEM micrograph are due to the presence of zinc ions in ZnWO4. Nanoparticles are having their sizes in the range 37-182 nm. The average Kelvin radius at 20°C room temperature is 27 Ả. Humidity sensing application of the pellets has been studied in a humidity control cabinet. It is observed that as relative humidity increases, there is decrease in the resistance of pellets in the range 10-85% RH. Sensing element of WO3-ZnO in 2:1 weight % ratio shows best results in 10-85 % relative humidity range. The average sensitivity of this sample is 1.20 MΩ/%RH. This sensing element shows good reproducibility, low hysteresis and less effect of aging.

Abstract: This study presents a new modus of selective removal technology and an excimer assistance on TFT-LCD above the five generation used to carry out the selective removal of nanostructures layers from optoelectronic flat panel displays’ color filter surface as well as the complete removal from the substrate of the ITO thin-films, RGB layer or resin BM layer. Displays’ color filters are produced using optoelectronic semiconductor fabrication techniques though the low yield during production can still be improved. Through the precise removal process of chemical etching and excimer assistance, the selective removals of different layers on top of color filter substrates will cut down the production costs. It can individually pick out and remove defective films or directly remove all films but the Cr layer or bare glass. Experimental results point out defective ITO thin-films, RGB layers, or resin BM layer can now be recycled with great precision. When the ITO proves difficult to remove, excimer-light can also be used to help with its removal. During the color filter recycle process the use of a 172nm excimer-light can remove stubborn film residues, effectively improving the quality of recycled color filters. This study offers a recovery module for defective diaplays’ color filters can be reused and fed back into the color filter production line, therefore provides many benefits in the industry of optoelectronic semiconductor.

Abstract: Large scale BaTiO3 nanorods were successfully synthesized by a template method based on a precipitation process. The templates used in our method are H2Ti8O17 nanorods, which can be synthesized from K2Ti4O9 fibers. The unique process of the synthesis is BaC2O4•0.5H2O shell was coated on the 1-dimensional H2Ti8O17 nanorods (the core). The as-prepared products were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that the BaTiO3 nanorods are ~100-300 nm in diameter and ~2-10 m in length. The process described provides a general route to fabricate this kind of perovskite 1-dimensional nanostructures, such as SrTiO3 and PbTiO3.

Abstract: After reheated at different temperatures for 5 minutes, the 400MPa Ultrafine Grained Steel specimens were air-cooled to room temperature, and then carried out the mechanical nanocrystallization surface treatment and structure performance testing. On the basis of comparing the test results on the specimens before and after the mechanical nanocrystallization surface treatment, the process of mechanical nanocrystallization was analyzed briefly. The results show that: as the reheating temperature rising, the trend of grain size growing increases markedly, and the mechanical properties also drop down to different degrees; when the reheating temperature is around 800°C, because of the pearlite spheroidized significantly, its mechanical properties drop the most seriously; after the mechanical nanocrystallization surface treatment, not only its surface form a layer of fine nano-layer (about 100 nm) structure, but also its mechanical properties rise obviously, and the yield strength is over 450MPa.

Abstract: Improved two step in-situ polymerization was applied in the preparation of urea- formaldehyde microcapsules used in microencapsulated electrophoretic display. The dispersion liquid which nano particles of titanium dioxide and carbon black dispersed in tetrachloroethylene was used as the electrophoretic liquid, and the electrophoresis microcapsules was prepared by urea-formaldehyde system. Melamine was used to modify the urea-formaldehyde microcapsules. The effect of different mole rates of urea and melamine to the surface morphology, mechanical strength, and sphericity of the microcapsules were studied. Electrophoretic performance of particles in melamine-urea-formaldehyde (MUF) microcapsules and urea-formaldehyde (UF) microcapsules were contrasted under the same condition. The results showed that as adding melamine in urea-formaldehyde, the time used to prepare microcapsules was shorter, and microcapsules were not easy aggregation during long time storage. When the mole rates of melamine and urea were from 2:8 to 5:5, the microcapsules with smoother surface (Fig.1), stronger mechanical strength and higher transmittance were obtained. Electrophoretic behaviors of particles in MUF (melamine and urea was 2:8 in mole rate) and UF microcapsules were tested under the same condition, respectively. It was shown that particles in MUF microcapsules could be seen significantly moving at the electric field of 10 V/mm, and the response time of these particles was 500 ms at the electric field of 20 V/mm，and it was shorter than 200 ms at the 50 V/mm electric field (Fig.2). On the contrast, the response time of particles in UF microcapsules was greater than 10 s at the electric field of 20 V/mm.

Abstract: Hollow TiOX nano-spheres have been successfully prepared using hollow core-shell latex particles as template, which involves the deposition of inorganic coating on the surface of hollow core-shell latex particles and subsequent removal of the latex particles by calcinations in air or ammonia gas. The formation route of hollow core-shell polymer particles is presented as follows: Firstly, poly-methyl methacrylate (PMMA) seed emulsions are prepared as the 'core'. Subsequently, the outer shell poly(styrene-co-methyl methacrylate) (PS-co-MMA) particles wrap on the surface of the core, the microspheres with core-shell have been prepared. Finally, Ti(OBu)4 is used as precursor for the preparation of hollow TiOX nanospheres. Transmission electron microscopy (TEM) and atom force microscopy (AFM) images of seed emulsions show they have the uniform size of about 470 nm. TEM of hollow core-shell polymers particles show they have an average diameter of about 500 nm. X-ray diffraction (XRD) analysis of TiO2 sample calcined presents that the strong absorptions is coordinated with the standard chart of rutile TiO2. TEM of TiO2 and TiO show hollow spheres well-dispersed with the diameter range of 300-400 nm and 350-400 nm, respectively. The density (in the atmospheric pressure, 20 °C) of TiO2 and TiO hollow spheres was 2.49 and 2.37 g∙mL-1, respectively. The Zeta potentials were 6.20 mV and 20.39 mV, respectively. Uniform hollow spheres show low density and good electrophoretic displays. The electrophoretic mobilities of white TiO2 and black TiO hollow spheres in tetrachloroethylene show they are suitable for electronic paper as background and display particles, respectively. It is anticipated that this method would present a potential toward the road of large-scale industrial production of TiOx hollow spheres.

Abstract: TiO2 nanomaterials with different dimensions(zero and one), sizes(20nm, 50nm and 100nm in diameter) and crystal structures(100% rutile, 100% anatase and combination of 20% rutile and 80% anatase) were confected to suspensions and ointment with varied concentrations and evaluated in animal model (Balb-c mouse). These mouse were divided into various groups randomly, with suspension intraperitoneally injected or ointment transdermally daubed. Heart, lung, liver and kidney were collected and prepared to HE sample after one week. Spectrophotometry was applied to study total antioxide capability and catalase activity of blood and tissues. It has been shown that all TiO2 nanomaterial groups had no effect on lives’ morphology and oxidative stress, with no obvious histopathological changes observed in heart, lung, liver and kidney, and these tissues presented no vacuolar degeneration, necrosis edema, engorgement and inflammation.

Abstract: Two new modified sandblasted and acid etched (SLA) surface methods had been used on commercially pure Ti (Cp-Ti) surface. Scanning electron microscopy investigation showed that modified SLA surfaces had micro- and nano-structure surface topography. Contact angle test showed that surface hydrophilicity was significantly increased after modified SLA surface modification. Human osteoblast-like MG63 cell attachment test showed that modified SLA surfaces would attach more cells than simple SLA surface. The alkaline phosphatase (ALP) activity assay indicated that ALP activity was enhanced on two modified SLA surfaces relative to SLA and mechanically polished Cp-Ti surface at early stage. Thus, subsequent chemical modification of SLA surface seems to be a promising method to generate better bioactive surface properties.