Results 261 to 270 of about 106,977 (306)

Colloid Geochemistry of Silica

1979
Silica, SiO2, is common in nature and occurs as seven distinct minerals, of which five show crystalline structures (quartz, tridimite, cristobalite, coesite, and stishovite) and two are amorphous (opal-A and lechatelierite). Lechatelierite is a silica glass and is very rare.
Shmuel Yariv, Harold Cross
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Free-Standing Silica Colloidal Nanoporous Membranes

Langmuir, 2009
We prepared robust free-standing 200 microm-thick colloidal membranes (nanofrits) with a relatively large area and no mechanical defects by sintering silica colloidal films. The silica spheres used to prepare the nanofrits were 338, 300, or 251 nm in diameter, leading to 25, 22.5, and 19 nm nanopore sizes, respectively. The room-temperature diffusional
Andrew K, Bohaty, Joanna J, Smith, Ilya, Zharov   +2 more
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Silica Colloidal Membranes with Enantioselective Permeability

Israel Journal of Chemistry, 2014
AbstractRobust mesoporous membranes composed of silica spheres were surface‐modified with chiral selector moieties, including small molecules, macrocycles, and polymers. Diffusion rates of enantiomers of a chiral dye through the resulting asymmetrically modified colloidal membranes were measured and the corresponding permselectivities were calculated ...
Ignacio-De Leon P., Abelow A., Cichelli J., Zhukov A., Stoikov I., Zharov I.   +5 more
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Surface modification of colloidal silica particles

Colloid & Polymer Science, 2001
Colloidal silica particles in organic solvents were grafted, using several reagents, in order to make them hydrophobic. The hydrophobicity of the beads could be easily varied. Quasielastic light scattering and transmission electron microscopy experiments showed that no aggregation occurs during the reaction when monofunctional agents are used ...
Poncet-Legrand, Celine, Bordes, Bertrand, Lafuma, Françoise   +2 more
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Porous Structure of Silica Colloidal Crystals

Langmuir, 2019
We prepared silica colloidal crystals with different pore sizes using isothermal heating evaporation-induced self-assembly in quantities suitable for nitrogen porosimetry and studied their porous structure. We observed pores of two types in agreement with the description of silica colloidal crystals as face-centered cubic packed structures containing ...
Andrey Galukhin, Dmitrii Bolmatenkov, Alina Emelianova, Ilya Zharov, Gennady Y. Gor   +4 more
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Electron microscopy of Ludox colloidal silica

Kolloid-Zeitschrift, 1960
The samples of Ludox colloidal silica, previously studied by light scattering, were examined in electron microscope. A considerable aggregation of particles was noted in solutions. The aggregates were efficiently removed by centrifugation, as was previously indicated by the decrease in dissymmetry of light scattered by the same sols.
Deželić, Gjuro, Wrischer, Mercedes, Devidé, Zvonimir, Kratohvil, Josip P.   +3 more
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Preparation and properties of poly(dimethyl siloxane)–colloidal silica/functionalized colloidal silica nanocomposites

Journal of Applied Polymer Science, 2012
AbstractAqueous spherical colloidal silica (CS) particles with a diameter of 15 ± 5 nm were modified with three different types of monofunctional silane coupling agents to prepare functionalized colloidal silica (FCS) particles. The effects of the surface chemistry of the FCS were studied as a function of the CS/FCS loading in the poly(dimethyl ...
Sumi Dinkar, A. Dhanabalan, B. H. S. Thimmappa   +2 more
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Effect of colloidal silica dispersions on the properties of PDMS‐colloidal silica composites

Journal of Applied Polymer Science, 2012
AbstractPolydimethylsiloxane (PDMS) colloidal silica composites prepared with the use of the dispersion of colloidal silica (CS) of similar particle size and distribution in different mediums/solvents are investigated for their rheological, thermal, and mechanical properties.
Dinkar Sumi, A. Dhanabalan, B. H. S. Thimmappa, Sriram Krishnamurthy   +3 more
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Dense silica-based coatings prepared from colloidal silica

Surface and Coatings Technology, 2005
Abstract Two sets of silica-based coatings have been prepared using two different wet methods. Set A was obtained using the conventional sol–gel method from thetraethyl-orthosilicate (TEOS) as the main precursor. Set B was produced from commercial colloidal silica added with two structural modifiers, KOH and sodium metasilicate (Na 2 SiO 3 5H 2 O ...
J.A. Calderón-Guillén, L.M. Avilés-Arellano, J.F. Pérez-Robles, J. González-Hernández, E. Ramos-Ramı́rez   +4 more
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Surface modification of colloidal silica

Langmuir, 1990
Les particules colloidales monodispersees de silice avec des diametres de 50 a 700 nm sont preparees par hydrolyse de tetraethyl orthosilicate dans l'eau, l'ammoniac et l'ethanol.
Rickey D. Badley, Warren T. Ford, Frank J. McEnroe, Roger A. Assink   +3 more
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