Materials Literature
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We describe an emulsion-based technique that allows the assembly of colloid particles into microstructured or multicomponent clusters (“supraparticles”). The particles are gathered, assembled, and fixed together in the restricted, colloid-size 2D or 3D space provided by emulsion droplets. The process is carried out by…
Nanocrystals of MgO and CaO have been prepared by a modified aerogel/hypercritical drying/dehydration method. For nanocrystalline MgO (AP-MgO) surface areas ranged from 250 to 500 m 2 /g, whereas for AP-CaO 100−160 m 2 /g. These materials have been compared with more conventional (CP) microcrystalline samples of lower…
The general design criteria and synthesis of four new peptide-based solid-state tubular array structures are described. Peptide nanotubes, which are extended tubular β-sheet-like structures, are constructed by the self-assembly of flat, ring-shaped peptide subunits made up of alternating d - and l -amino acid residues…
General principles guiding selection and use of particulate materials principle types of particulate fillers analytical techniques for characterizing filler surfaces surface modifications and surface modifiers preparation and mixture characterization of particulate filled polymer compounds effect on particulate filler…
A series of mesoporous MCM-41 and HMS silica molecular sieves have been prepared by electrostatic and neutral assembly pathways, respectively, and their properties have been compared by a variety of physical techniques. Direct S + I - charge matching between cationic quaternary ammonium ion surfactants (S + ) and the…
The synthesis and photophysical characterization of nanometer-size ZnS with and without Mn 2+ are reported. Without Mn 2+, the ZnS nanoclusters emit in the blue upon ultraviolet excitation. ZnS doped with 1−5% Mn 2+ (presumably in Zn 2+ sites) yields the orange emission observed for bulk Zn:Mn phosphors but with great…
We present the results of new and previously published 17 O NMR, EPR, and NMRD studies of aqueous solutions of the Gd 3+ octaaqua ion and the commercial MRI contrast agents [Gd(DTPA)(H 2 O)] 2 - (MAGNEVIST, Schering AG, DTPA = 1,1,4,7,7-pentakis(carboxymethyl)-1,4,7-triazaheptane), [Gd(DTPA-BMA)(H 2 O)] (OMNISCAN, San…
Organically functionalized mesoporous silicas are prepared at room temperature by the co-condensation of tetraethoxysilane and organosiloxanes in the presence of surfactant templates; the resulting materials are the first examples of covalently linked, ordered, hybrid inorganic–organic networks.
A technique is described for fabricating arrays of uniform CdS nanowires with lengths up to 1 μm and diameters as small as 9 nm by electrochemically depositing the semiconductor directly into the pores of anodic aluminum oxide films from an electrolyte containing Cd 2+ and S in dimethyl sulfoxide. The nanowire arrays…
This volume presents recent advances in selcted topics on the chemistry, structure, and bonding of Zintl phases and Zintl ions. Areas covered include: the use of Zintl phases as precursors to novel solid state compounds; and electrochemical synthesis of novel Zintl phases; Zintl phases at the metal-insulator border; r…
An integral isoconversional method provides a linear procedure to estimate the activation energy ( E α ) at a given conversion (α) but only when an oversimplified approximation of the temperature integral ( p ( x ), where x = E / RT, R is the gas constant and T is the temperature) is used. Although the relative error…
Starting from the naturally occurring structure of porous aluminum oxide, a polymer mold suitable for the formation of titanium dioxide nanotubes was obtained. The tubular structure was formed by electrochemical deposition in the mold. After dissolution of the polymer, titanium dioxide nanotubes were obtained and char…
Crystalline mesoporous molecular sieves may be prepared under a wide range of conditions in the presence of cationic, anionic, gemini, or neutral surfactants. These mesostructured materials include pure and modified silicates, other metallic oxides and sulfides as well as aluminophosphates. Air calcination of silicate…
This review discusses two classes of organic template-derived amorphous silicas distinguished by the nature of template-matrix interactions and the extent to which subsequent processing dictates the final pore morphology. First we discuss surfactant-templated silicas where the template-matrix interaction is via non-co…
The formation of ordered phases of acid-hydrolyzed cellulose suspensions was studied as a function of cellulose crystallite concentration and added electrolyte (HCl, NaCl, and KCl) concentrations. A chiral nematic phase formed when the suspension concentration was higher than 5.14 × 10 -6 nm -3 in water. For biphasic…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCarbide and Nitride Overlayers on Early Transition Metal Surfaces: Preparation, Characterization, and ReactivitiesJingguang G. ChenView Author Information Corporate Research Laboratories, Exxon Research and Engineering Company, Annandale, New Jersey 08801 Cite this: Chem. Re…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTCalix[4]pyrroles: Old Yet New Anion-Binding AgentsPhilip A. Gale, Jonathan L. Sessler, Vladimír Král, and Vincent LynchView Author Information Department of Chemistry and Biochemistry University of Texas at Austin, Austin, Texas 78712-1167 Cite this: J. Am. Chem. Soc.…
Carbon dioxide reforming of methane produces synthesis gas with a low hydrogen to carbon monoxide ratio, which is desirable for many industrial synthesis processes. This reaction also has very important environmental implications since both methane and carbon dioxide contribute to the greenhouse effect. Converting the…
Super water-repellent surfaces showing a contact angle of 174° for water droplets have been made of alkylketene dimer (AKD). Water droplets roll around without attachment on the super water-repellent surfaces when tilted slightly. The AKD is a kind of wax and forms spontaneously a fractal structure in its surfaces by…
A layered protonic titanate of lepidocrocite-type, H x Ti 2- x /4 □ x /4 O 4 ·H 2 O ( x ∼ 0.7; □, vacancy), has been exfoliated on the action of an aqueous solution of tetrabutylammonium (hereafter TBA) hydroxide, which resulted in a stable colloidal suspension. A colloidal aggregate centrifuged from the suspension wa…