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Liquid Precursor (liquid + precursor)
Selected AbstractsHollow Zinc Oxide Mesocrystals from an Ionic Liquid Precursor (ILP),ADVANCED MATERIALS, Issue 7 2008Zhonghao Li The highly hydrated ionic liquid tetrabutylammonium hydroxide (TBAH) is an efficient ionic liquid precursor (ILP) for the fabrication of zinc oxide mesocrystals. Upon reaction of TBAH with zinc acetate, individual nanometer-sized ZnO building blocks assemble into highly correlated ZnO mesocrystals. The mesocrystals are up to ca. 10 µm in length and the larger crystals have a channel running along the long crystal axis. [source] Uniform Metal (Hydr)Oxide Particles from Water/Ionic Liquid Precursor (ILP) MixturesCHEMISTRY - A EUROPEAN JOURNAL, Issue 27 2008Zhonghao Li Dr. Abstract We have recently shown that the hydrated ionic liquid tetrabutylammonium hydroxide (TBAH) is an efficient ionic liquid precursor (ILP) for the fabrication of ZnO/carbohydrate materials (D. Mumalo-Djokic, W.,B. Stern, A. Taubert, Cryst. Growth Des.2008, 8, 330). The current paper shows that ZnO is just one example out of the large group of technologically important metal (hydr)oxides that can be made using TBAH. Simply by using different metal acetates as precursors in TBAH, it is possible to make a wide variety of metal (hydr)oxides with well-defined size, morphology, and chemical composition. It is also possible to dope metal oxide particles or to synthesize mixed metal oxide particles, and therefore to control properties like magnetism. [source] Pigment Synthesis: PY181 Pigment Microspheres of Nanoplates Synthesized via Polymer-Induced Liquid Precursors (Adv. Funct.ADVANCED FUNCTIONAL MATERIALS, Issue 13 2009Mater. A polymer-induced liquid precursor is used for a pigment yellow 181 crystal formed by chemical reaction in mixed solvents of water and isopropanol by direct azo coupling under the directing influence of a designed copolymer additive. This leads to a pigment with novel complex morphology and unusal properties, as shown by Cölfen et al. on page 2095. [source] PY181 Pigment Microspheres of Nanoplates Synthesized via Polymer-Induced Liquid PrecursorsADVANCED FUNCTIONAL MATERIALS, Issue 13 2009Yurong Ma Abstract Organic pigments are important crystalline substances, and their properties and applications rely on size and shape control. Pigment Yellow 181 (PY181) is an industrial azo pigment that is light and weatherfast and suitable for high temperature processing. One disadvantage is its needle-like shape in the default , -phase, which makes the pigment difficult to process in industry, e.g., in polymer melts, where a spherical structure would be ideal. Here, we show for the first time, that polymer-induced liquid precursor structures can be formed even in association to a chemical reaction. Furthermore, it is demonstrated that biomineralization principles can be exploited for the generation of advanced functional materials, such as pigments with novel complex morphology and different properties. Stable PY181 microspheres of nanoplates in the , -phase were obtained in mixed solvents of water and isopropanol by direct azo coupling under the directing influence of a designed copolymer additive aminobenzoylaminobenzamide-acetoacetyl-poly(ethylene imine)- block -poly(ethylene glycol) (ABABA-acetoacetyl-PEI- b -PEG). [source] Silica-Based, Organically Modified Host Material for Waveguide Structuring by Two-Photon-Induced PhotopolymerizationADVANCED FUNCTIONAL MATERIALS, Issue 5 2010Stefan Krivec Abstract The three-dimensional fabrication of optical waveguides has gained increasing interest in recent years to establish interconnections between electrical components on a very small scale where copper circuits encounter severe limitations. In this work the application of optically clear, organically modified porous silica monoliths and thin films as a host material for polymeric waveguides to be inscribed into the solid host structure by two-photon-induced photopolymerization is investigated. Porosity is generated using a lyotropic liquid crystalline surfactant/solvent system as a template for the solid silica material obtained by a sol,gel transition of a liquid precursor. In order to reduce the brittleness of the purely inorganic material, organic,inorganic co-precursor molecules that contain poly(ethylene glycol) chains are synthesized and added to the mixture, which successfully suppresses macroscopic cracking and leads to flexible thin films. The structure of the thus-obtained porous organic,inorganic hybrid material is investigated by atomic force microscopy. It is shown that the modified material is suitable for infiltration with photocurable monomers and functional polymeric waveguides can be inscribed by selective two-photon-induced photopolymerization. [source] Pigment Synthesis: PY181 Pigment Microspheres of Nanoplates Synthesized via Polymer-Induced Liquid Precursors (Adv. Funct.ADVANCED FUNCTIONAL MATERIALS, Issue 13 2009Mater. A polymer-induced liquid precursor is used for a pigment yellow 181 crystal formed by chemical reaction in mixed solvents of water and isopropanol by direct azo coupling under the directing influence of a designed copolymer additive. This leads to a pigment with novel complex morphology and unusal properties, as shown by Cölfen et al. on page 2095. [source] Hollow Zinc Oxide Mesocrystals from an Ionic Liquid Precursor (ILP),ADVANCED MATERIALS, Issue 7 2008Zhonghao Li The highly hydrated ionic liquid tetrabutylammonium hydroxide (TBAH) is an efficient ionic liquid precursor (ILP) for the fabrication of zinc oxide mesocrystals. Upon reaction of TBAH with zinc acetate, individual nanometer-sized ZnO building blocks assemble into highly correlated ZnO mesocrystals. The mesocrystals are up to ca. 10 µm in length and the larger crystals have a channel running along the long crystal axis. [source] Catalytic porous ceramic prepared in-situ by sol-gelation for butane-to-syngas processing in microreactorsAICHE JOURNAL, Issue 7 2009Nico Hotz Abstract In this study, a novel flow-based method is presented to place catalytic nanoparticles into a reactor by sol-gelation of a porous ceramic consisting of Rh/ceria/zirconia nanoparticles, silica sand, ceramic binder, and a gelation agent. This method allows for the placement of a liquid precursor containing the catalyst into the final reactor geometry without the need of impregnating or coating of a substrate with the catalytic material. The so generated foam-like porous ceramic shows properties highly appropriate for use as catalytic reactor material, e.g., reasonable pressure drop due to its porosity, high thermal and catalytic stability, and excellent catalytic behavior. To investigate the catalytic activity, microreactors containing this foam-like ceramic are employed for the production of hydrogen and carbon monoxide-rich syngas from butane. The effect of operating parameters such as the inlet flow rate on the hydrocarbon processing is analyzed and the limitation of the reactor by diffusion mass transport is investigated. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] Trace element studies of silicate-rich inclusions in the Guin (UNGR) and Kodaikanal (IIE) iron meteoritesMETEORITICS & PLANETARY SCIENCE, Issue 7-8 2007Gero Kurat It contains a rutile grain and is in contact with a large Cl apatite. The latter is very rich in rare earth elements (REEs) (,80 × CI), which display a flat abundance pattern, except for Eu and Yb, which are underabundant. The devitrified glass is very poor in REEs (<0.1 × CI), except for Eu and Yb, which have positive abundance anomalies. Devitrified glass and Cl apatite are out of chemical equilibrium and their complementary REE patterns indicate a genesis via condensation under reducing conditions. Inclusion 1 in the Kodaikanal (IIE) iron consists of glass only, whereas inclusion 2 consists of clinopyroxene, which is partly overgrown by low-Ca pyroxene, and apatite embedded in devitrified glass. All minerals are euhedral or have skeletal habits indicating crystallization from the liquid precursor of the glass. Pyroxenes and the apatite are rich in trace elements, indicating crystallization from a liquid that had 10,50 × CI abundances of REEs and refractory lithophile elements (RLEs). The co-existing glass is poor in REEs (,0.1,1 × CI) and, consequently, a liquid of such chemical composition cannot have crystallized the phenocrysts. Glasses have variable chemical compositions but are rich in SiO2, Al2O3, Na2O, and K2O as well as in HFSEs, Be, B, and Rb. The REE abundance patterns are mostly flat, except for the glass-only inclusion, which has heavy rare earth elements (HREEs) > light rare earth elements (LREEs) and deficits in Eu and Yb,an ultrarefractory pattern. The genetic models suggested so far cannot explain what is observed and, consequently, we offer a new model for silicate inclusion formation in IIE and related irons. Nebular processes and a relationship with E meteorites (Guin) or Ca-Al-rich inclusions (CAIs) (Kodaikanal) are indicated. A sequence of condensation (CaS, TiN or refractory pyroxene-rich liquids) and vapor-solid elemental exchange can be identified that took place beginning under reducing and ending at oxidizing conditions (phosphate, rutile formation, alkali and Fe2+ metasomatism, metasomatic loss of REEs from glass). [source] Selective extraction of polyunsaturated triacylglycerols using a novel ionic liquid precursor immobilized on a mesoporous complexing adsorbentBIOTECHNOLOGY PROGRESS, Issue 5 2009Patrisha J. Pham Abstract Mesoporous silica (SBA-15) synthesized by using Pluronic123 as the structure-directing template was functionalized by imidazolium-based ionic liquid precursors. Silver salts were then immobilized onto the supported ionic liquids using the incipient wetness impregnation technique. The separation of unsaturated species was achieved through the reversible and specific interaction between silver ions and carbon,carbon double bonds. This adsorbent was examined for the selective separation of polyunsaturated triacylglycerols (PUTAG) using High Pressure Liquid Chromatography (HPLC) with Evaporative Light Scattering Detection (ELSD) as the quantification methodology. AgBF4/SBA15·HPSiOEtIM·PF6 showed an adsorption capacity for linolenin of about 217 mg adsorbed/gram of sorbent. This adsorbent had good selectivity and a high capacity for the most highly unsaturated triacylglycerol when applied to a mixture of triacylglycerols with varying degrees of unsaturation. Consequently, a stepwise methodology was also developed to increase the recovery of the adsorbed components. This adsorbent retained its selectivity and capacity when recycled up to five times. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009 [source] Special Issue on Aerosol-Assisted Chemical Vapor DepositionCHEMICAL VAPOR DEPOSITION, Issue 10 2006Kwang-Leong Choy As a variant of conventional CVD, AACVD involves atomization of a liquid precursor into fine aerosol droplets that are delivered to a heated zone where evaporation, decomposition, and subsequent CVD reactions occur. In this editorial, Guest Editor Kwang-Leong Choy provides a brief overview of the articles in this Special Issue and some of the recent advances in this dynamic field. [source] Synthesis of Al2O3,SiO2 Films by Ar/O2 Plasma-Enhanced CVD from Alkoxide Precursors,CHEMICAL VAPOR DEPOSITION, Issue 5 2006Y. Li Amorphous Al2O3, SiO2, and Al2O3,SiO2 composite films have been produced at 800,°C from alkoxide solution precursors by liquid-injection oxygen plasma enhanced CVD. The films' structures and morphologies are affected by the feed rate of the liquid precursor and their compositions can be controlled by adjusting the Si/Al ratios in the starting source. Steel substrates coated with the above films gained excellent protection when they were exposed to high temperature atmosphere containing KCl vapor. [source] Uniform Metal (Hydr)Oxide Particles from Water/Ionic Liquid Precursor (ILP) MixturesCHEMISTRY - A EUROPEAN JOURNAL, Issue 27 2008Zhonghao Li Dr. Abstract We have recently shown that the hydrated ionic liquid tetrabutylammonium hydroxide (TBAH) is an efficient ionic liquid precursor (ILP) for the fabrication of ZnO/carbohydrate materials (D. Mumalo-Djokic, W.,B. Stern, A. Taubert, Cryst. Growth Des.2008, 8, 330). The current paper shows that ZnO is just one example out of the large group of technologically important metal (hydr)oxides that can be made using TBAH. Simply by using different metal acetates as precursors in TBAH, it is possible to make a wide variety of metal (hydr)oxides with well-defined size, morphology, and chemical composition. It is also possible to dope metal oxide particles or to synthesize mixed metal oxide particles, and therefore to control properties like magnetism. [source] New supplying evaporation precursor method with CVDHEAT TRANSFER - ASIAN RESEARCH (FORMERLY HEAT TRANSFER-JAPANESE RESEARCH), Issue 5 2009Motohiro Oshima Abstract We propose a novel system of chemical vapor deposition (CVD), i.e., flash boiling spray CVD (SF-CVD) to eliminate several kinds of problems, such as the decomposition of precursors in the supply line and evaporator. In this method, liquid precursors are supplied directly to the vacuum chamber through an injector, just like fuel for an automobile engine, without any vaporizers, so as to induce an unsteady and intermittent flash boiling spray in the chamber. However, it is necessary to keep the lowest ambient pressure possible because the saturated vapor pressure of the precursors is very low. Thus, this is very useful for modifying the saturated vapor pressure of the precursors. A technique of lowering the vaporization pressure is proposed by mixing a more saturated vapor-pressure organic solvent with a precursor. To determine the principles underlying FS-CVD, we first formed SiO2 film on the Si substrate. A mixed solution of tetraethylorthosilicate (TEOS) and n-pentane was used as the mixing solution. The film thickness distribution of SiO2 film on a 100-mm-diameter Si wafer was ±4% using this method. Furthermore, this method enabled us to control film with various thicknesses by optimizing the injection duration, cycle, and injection cycle per second. © 2009 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.20235 [source] Selective extraction of polyunsaturated triacylglycerols using a novel ionic liquid precursor immobilized on a mesoporous complexing adsorbentBIOTECHNOLOGY PROGRESS, Issue 5 2009Patrisha J. Pham Abstract Mesoporous silica (SBA-15) synthesized by using Pluronic123 as the structure-directing template was functionalized by imidazolium-based ionic liquid precursors. Silver salts were then immobilized onto the supported ionic liquids using the incipient wetness impregnation technique. The separation of unsaturated species was achieved through the reversible and specific interaction between silver ions and carbon,carbon double bonds. This adsorbent was examined for the selective separation of polyunsaturated triacylglycerols (PUTAG) using High Pressure Liquid Chromatography (HPLC) with Evaporative Light Scattering Detection (ELSD) as the quantification methodology. AgBF4/SBA15·HPSiOEtIM·PF6 showed an adsorption capacity for linolenin of about 217 mg adsorbed/gram of sorbent. This adsorbent had good selectivity and a high capacity for the most highly unsaturated triacylglycerol when applied to a mixture of triacylglycerols with varying degrees of unsaturation. Consequently, a stepwise methodology was also developed to increase the recovery of the adsorbed components. This adsorbent retained its selectivity and capacity when recycled up to five times. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009 [source] | |||||||||||||