Advanced Materials Research Vols. 634-638

Abstract: Based on the profound application, the Co₃O₄ was chosen to be research object; the optimized dispersing condition was studied and determined as: dosage of Co₃O₄ nano particle varied from 0.01 to 0.02mg/ml, sodium citrate was determined to be dispersing adjuvant with a dosage of 0.0005g/ml, ultrasonic time: 10min, and pH value was 7 to 8 when the Zeta potential was –57.1mv. After a detailed discussion of size distribution and dispersing condition, the size distribution of Co₃O₄ nano particle was measured with Malvern Nano Zetasizer to be 217nm.

Abstract: M-phase vanadium dioxides (VO₂) is synthesized by hydrothermal-solvothermal method. In this process,V₂O₅ powder is used as raw materials,cetyltrimethylammonium bromide (CTAB) is used as templates and hydrazine combined with different alcohols such as ethanol, propanol and butanol are used as reductants. X-ray diffraction (XRD) and scanning electron microscopy (SEM) are used to test the properties of VO₂ nanoparticles. The results show that VO₂(M) nano-particles were succsessfully synthesized under the conditions of thermal reduction temperature 250°C, reaction time 8h and drying temperature 60°C. The variety of alcoholic reducing agents plays an important role in the structure and morphology of the product VO₂(M). That makes the size of the particles smaller, and with the carbon atom numbers increasing, the crystallinity is better.The different methods of adding CTAB affect the polycrystalline structure of the product, which is VO₂(B) or VO₂(M).

Abstract: In this paper, carbon spheres were synthesized by CVD method. These carbon spheres exhibit diameters of about 200 nm. Thermal gravimetric analysis indicated the good stability in high temperature of the carbon spheres. The products were treated by microwave plasma and high temperature vacuum heat treatments respectively. The products were characterized by X-ray diffraction, Raman spectroscopy and Field Emission Scanning Electron Microscope. The study indicated that the original products, with perfect morphology and low graphitization degree, were converted to crystal. The different techniques were considered for the influence on the graphitization degree.

Abstract: In the present work, TiOF₂ ball-flowers were successfully synthesized through a simple low temperature hydrothermal route using titanium butoxide and hydrofluoric acid as precursors. The effect of synthesis temperature on the morphology of TiOF₂ ball-flowers was also studied by scanning electron microscopy (SEM). The crystal characteristics of TiOF₂ were analyzed based on X-ray powder diffraction (XRD) and transmission electron microscopy (TEM), which revealed that the TiOF₂ ball-flowers were consist of hexagonal and cubic single crystal TiOF₂ sheets. After an annealing treatment of 500°C for 2h, the single crystal TiOF₂ sheets were converted to single crystal anatase TiO2 sheets exposed with {116} and {001} facets exposed respectively.

Abstract: Barium strontium titanate nano powders were prepared by mixing ethanol solution of tetrabutyl titanate with an aqueous solution of Ba(OH)₂•8H₂O and Sr(OH)₂•8H₂O with a certain molar ratio of barium to strontium at 40°C－95°C. The products were characterized by thermogravimetry (TG), Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), transmission electron microscope (TEM) and atomic force microscopy (AFM). The results show that the powders prepared with the reactant concentration of 0.8M are spherical in particle shape with the grain size of 50nm－65nm. When the annealing temperature of the powders is higher than 906°C, the hydroxyl groups existed in barium strontium titanate lattice are removed. XRD analysis demonstrate that the as-prepared powders are cubic phase. All the diffraction peaks are shifted towards higher diffraction angles and the lattice parameter a calculated decreases linearly with serial decrease of the molar ratio of barium to strontium.

Abstract: The effect of functionalization of multi-walled carbon nanotubes (MWCNT) on the thermal stbility of MWCNT/epoxy nanocomposites was investigated. Epoxy-based nanocomposites reinforced with MWCNTs with and without functionalization were prepared. The thermal stability of nanocomposites was characterized using thermal gravimetric analysis (TGA). Experimental results showed that functionalization of MWCNTs enhanced the decomposition temperature of MWCNTs reinforced nanocomposite compared to those containing pristine MWCNTs.

Abstract: Anatase and rutile TiO₂ nanostructure have been successfully synthesized via CD reactive magnetron sputtering and hydrothermal synthesis followed by post-treatment from titanium powder. The morphology and crystalline structure of the nanostructure are characterized in detail with X-ray diffraction (XRD), Field Emissiom Scanning Electron Microscope (FE-SEM), Scanning Electron Microscope (SEM), energy dispersive X- ray and energy dispersive x-ray analyzer (EDX). The pattern showed anatase and rutile phase crystalline structure. The thin films showed the surface as viewed uniform tiny spots distribution. TiO2 nanostructures were successfully synthesized using a simple hydrothermal synthesis method from TiO2 nan_{Subscript text}oparticles. The samples were synthesized by means of the hydrothermal reaction of TiO₂ nanoparticle of anatase and rutile phase. In a typical procedure, The time were varied, and cooled to room temperature, naturally. The samples showed structures of crystalline, anatase and rutile phases. They were morphology TiO₂ nanorods, TiO₂ nanowires and TiO₂ nano shape with the diameters of about 30-300 nm. The EDX analysis of an area containing a large amount of TiO₂ nanostructure reveals the existence of Na, Ti and O elements.

Abstract: A polymer-grafted SrAl2O4: Eu2+, Dy3+ (PG-SAO-ED) were synthesized by using a bi-functional ligand (3-allyl-2, 4-pentanedione, denoted as APD) as a bridge, which can coordinate with the unsaturated metal ions on the surface of SrAl2O4: Eu2+, Dy3+ (SAO-ED) at one end, and copolymerize with methyl methacrylate and styrene at the other end. The sample was analyzed by FT-IR and Powder X-ray diffraction patterns (XRD). The PG-SAO-ED can well be applied in painting or ink, they have good miscibility with organics. The luminescent painting containing PG-SAO-ED has greatly higher water resistance than that containing SAO-ED.

Abstract: One-step rapid synthesis of colloidal nano-MnO2 suspension from KMnO4 solution has been readily carried out in the presence of nanocellulose whiskers (NCW) upon a sonochemistry procedure at room temperature. NCW that plays a triple role of a reducing agent and a support, as well as of a stabilizer, has been introduced to obtain stable dispersions of MnO2 nanoparticles. UV-vis spectroscopy, XRD, and TEM were employed to characterize the products. Uniform α-MnO2 nanoparticles of dimensions 20–30 nm were obtained with good crystalinity and phase-purity by air- calcination treatment at 500 °C.

Abstract: The carbon-encapsulated superparamagnetic colloidal nanoparticles (SCNps) were rigidized into soft solids by embedding the SCNps into polyacrylamide hydrogel matrixes under the induction of an external magnetic field. Stabilized by the balance of attractive (magnetic) and repulsive (electrostatic) forces, the SCNps form one-dimension photonic crystal structures along the direction of the external magnetic field and further the structures are frozen into the solidified polymer matrix. The polymer matrix embedded one-dimension photonic crystal structures can strongly diffract visible light and present brilliant color in the light. This novel and soft solid polymer matrix that could be shaped and sliced not only paves a new avenue for develop novel magnetic-responsive photonic crystal materials and devices, but also provides a method to observe the magnetic-induced self-assembly structures of the SCNps in media such as polyacrylamide hydrogel matrixs as a result of the ordered structures frozen into the polyacrylamide hydrogel matrixs. So we can reveal the relationship between their structure and color, and furthermore permit a systematic exploration on magnetically induced self-assembling dynamics, colloidal crystallography which have important significance in the large-scale industrial production in the future.