Macroporous fluoropolymeric films templated by silica colloidal assembly: A possible route to super-hydrophobic surfaces

A super-hydrophobic surface was obtained on a three-dimensional (313) polyvinylidene fluoride (PVDF) macroporous film. The porous films were fabricated through self-assembled silica colloidal templates. The apparent water contact angle of the surface can be tuned from 106 degrees to 153 degrees through altering the sintering temperature and the diameter of the colloidal templates. A composite structure of micro-cavities and nanoholes on the PVDF surface was responsible for the super-hydrophobicity. The wettability of the porous surfaces was described by the use of the Cassie-Baxter model and Wenzel's equation.

Synthesis and fluorescence properties of Eu2+-doped KMgF3 nanoparticles

The phase diagram of a cetyltrimethyl ammonium bromide( CTAB)/n-butanol/n-octane/KNO3-Mg( NO3)(2) system was drawn. Nanoparticles of Eu2+-doped KMgF3 were prepared from the quaternary microemulsions of cetyltrimethyl ammonium bromide(CTAB), n-butanol, n-octane and water. The X-ray diffraction(XRD) patterns were indexed to a pure KMgF3 cubic phase. The environmental scanning electron microscopic (ESEM) images show the presence of spherical Eu2+-doped KMgF3 nanoparticles with a diameter of ca. 20 nm. The emission of KMgF3: Eu2+ nanoparticles peaks at 360 mn. The excitation band was observed at 250 nm with a blue shift of ca. 70 nm compared with that of KMgF3: Eu2+ single crystal. The preparation method of nano-KMgF3: Eu2+/PMMA composite films was inquired into.

Optical spectroscopy properties of KMgF3 : Eu2+ nanocrystals and powder synthesized by microemulsion and solvothermal process

Nanocrystals and powders of KMgF3 doped with Eu2+ were synthesized by the microemulsion method and the solvothermal process, respectively. The emission and excitation spectra of KMgF3:Eu2+ phosphors were measured and compared with those of the samples synthesized through a solid. state reaction, Bridgman-Stockbarger method, and mild hydrothermal technique. The KMgF3: Eu2+ samples synthesized by means of the microemulsion method and the solvothermal process show only a sharp emission peak located at 360 nm, in the emission spectra, which arises from the f -> f(P-6(1/2)-> S-8(1/2)) transition of Eu2+. The broad emission bands appear at 420 nm,,which arises from Eu2+ <- O2- cannot be observed(in the mild hydrothermal and single crystal samples, the emission peak at 420 nm besides the emission of Eu2+ at 360 nm is observed). In the excitation spectrum of the KMgF3: Eu2+ samples synthesized by the microemulsion method and the solvothermal process, the excitation peaks show an intensive blue shift. The blue shift can he attributed to the lower oxygenic content in the KMgF3: Eu2+ samples synthesized by the microemulsion method and the solvothermal process.

Crystallization and melting behaviors of PPC-BS/PVA blends

The isothermal crystallization and melting behaviors of poly(propylene carbonate) end-capped with benzenesulfonyl/poly (vinyl alcohol) (PPC-BS/PVA) blends over rich PVA composition range were first investigated by differential scanning calorimetry (DSC). PPS-BS/PVA interaction parameter, chi(12), calculated from equilibrium melting temperature depression was -0.44, revealing miscibility of PPC-BS with PVA in the melt and favorable interactions. The temperature dependence of crystallization rate constant at initial crystallization stage was analyzed using the modified Lauritzen-Hoffman expression. The chain width, a(0), the thickness of a monomolecular layer, b(0), the fold and lateral surface-free energies, sigma(e) and sigma, and the work of chain folding, q, for neat PVA were first reckoned to be 4.50 Angstrom, 4.78 Angstrom, 76.0 erg.cm(-2), and 4.70 kcal.mol(-1), respectively. The values of sigma(e) and q for PVA in PPC-BS/PVA blends exhibited a maximum in the neighborhood of 10/90 PPC-BS/PV, respectively.

TiO2-SnO2复合凝胶的水-乙醇蒸汽吸附动力学研究

中国科学院山西煤炭化学研究所

TiO2-SnO2复合凝胶的结构表征及其吸附与催化性能研究

中国科学院山西煤炭化学研究所

Preparation and properties of abzyme with thyroxine deiodinase

The abzyme (Se-6E8) with a higher thyroxine deiodinase activity was prepared by modifying the serine residues of monoclonal antibody (6E8)with phenylmethanesulfonyl fluoride and sodium hydrogen selenide, and the 6E8 against O-methyl-T-4, which is a kind of thyroxine derivatives and was taken as a hapten for the first time. Two bands were found corresponding to the 5.5 kD heavy chain and the 2.7 kD light chain respectively by SDS-PAGE. The characteristics of dissociation constants, pH, and temperature were also studied. The results show that the activity of Se-6E8 is 2 010 U/mumol protein, and the proper temperature and pH of the catalytic reactions is 57 degreesC and 8.2 respectively.

Carbon ceramic electrodes bulk-modified with nanoparticles of ferrocenebutyrate-intercalated Mg-Al layered double hydroxide

Ferrocenebutyrate-intercalated layered double hydroxide (FcLDH) was prepared by the coprecipitation method and characterized by PXRD, FTIR, TEM and elemental analysis. FcLDH nanoparticles in deionized water were deposited onto the surface of graphite powder to yield graphite powder-supported FcLDH, which was subsequently dispersed into methyltrimethoxysilane-derived gels to fabricate surface-renewable, stable, rigid carbon ceramic electrodes containing the electroactive ferrocenyl group. Cyclic voltammetric study revealed that peak currents of the FcLDH-modified electrode were diffusion-con trolled in 0.1 mol l(-1) KCl aqueous solution. In addition, the formal potential of the modified electrode is related to the activity of chloride ion with a Nernst slope of 56 mV per decade.

Sol-gel derived carbon ceramic electrode containing methylene blue-intercalted alpha-zirconium phosphate micro particles

Methylene blue-intercalated a-zirconium phosphate (MBZrP) micro particles in deionized water were deposited onto the surface of graphite powder to prepare graphite powder-supported MBZrP, which was subsequently dispersed into methyltrimethoxysilane-derived gels to yield a conductive composite. The composite was used as electrode material to fabricate a surface-renewable, rigid, leak-free carbon ceramic composite electrode, bulk-modified with methylene blue (MB). In the configuration, alpha-zirconium phosphate was employed as a solid host for MB, which acted as a catalyst. Graphite powder ensured conductivity by percolation, the silicate provided a rigid porous backbone and the methyl groups endowed hydrophobicity and thus limited the wetting section of the modified electrode. Peak currents of the MBZrP-modified electrode were surface-confined at low scan rates but diffusion-controlled at high scan rates. Square-wave voltammetric study revealed that MBZrP immobilized in carbon ceramic matrix presented a two-electron, three-proton redox process in acidic aqueous solution with pH ranged from 0.44 to 2.94. In addition, the chemically modified electrode showed an electrocatalytic activity toward nitrite reduction at +0.15 V (vs. Ag/AgCl) in acidic aqueous solution (pH=0.44). The linear range and detection limit are 1 x 10(-6)-4 x 10(-3) mol L-1 and 1.5 x 10(-7) mol L-1, respectively.

Photoluminescence of organic-inorganic hybrid SiO2 xerogels

Organic-inorganic hybrid SiO2 xerogels were prepared by the sol-gel method under various preparation conditions and compositions by using tetraethoxysilane (TEOS), (3-aminopropyl) triethoxysilane (A-PS), (3-glycidoxypropyl) trimethoxysilane (GPS), organic acid (CH3COOH) and inorganic acids (HCl, HNO3, H2SO4) as the main precursors. Luminescence and FT-IR spectra were used to characterize the resulted hybrid SiO2 xerogels. The result of FT-IR spectrum shows that the xerogels are composed of non-crystalline -Si-O-Si- networks containing some organic groups such as -NH, -CH and -OH. Under the excitation of 365 nm, all the hybrid xerogels exhibit strong luminescence in the blue region, but the emission intensity and position depend on the starting precursor compositions to a large extent. Suitable amount of polyethylene glycol (PEG500 and PEG10000) in the hybrid xerogels can enhance the emission intensity. Additionally, the emission intensity of the hybrid xerogels increases with heat treatment temperature in the range of ambient to 200degreesC, and vacuum condition is also able to enhance the emission intensity.