Chemical modification of silica surfaces

Reuter, Anett; Heger, K.; Uhlig, M.; Libera, Lothar; Marx, G.

doi:10.1007/bf00323282

Cited by 4 publications

(3 citation statements)

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“…The carbon-hydrogen and oxygen-hydrogen stretching vibrations are obviously associated with the organic matter of the grass blades. The SiO 4 stretching and bending vibrations will be found in the spectral interval between 300 cm -1 and 1300 cm -1 [20,21]. The silicon-oxygen-silicon vibrations are apparently small in as-grown samples without preparation.…”

Section: Resultsmentioning

confidence: 99%

A new attempt to study biomineralised silica bodies in Dactylis glomerata L.

Dietrich

Hemeltjen

Meyer

et al. 2002

Analytical and Bioanalytical Chemistry

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The accumulation process of inorganic compounds in animals and plants by biomineralisation is not well understood nowadays, though it may be the key to an environmental-compatible production of modern materials in future. In this paper a new attempt will be made on the investigation of silica accumulation in grasses (especially Dactylis glomerata L.). The silicic acid agglomerates in Dactylis glomerata L. were studied by means of scanning electron microscopy in combination with energy dispersive X-ray spectrometry as well as infrared and micro-RAMAN spectrometry.In particular blades were prepared by critical point drying or shock-freezing for anatomical studies of silica cells and bristles in the plant tissue. SEM imaging and EDX microanalysis for elemental composition were done in the cryostage as well as under variable pressure. The localized silica bodies were examined for their structural properties by means of IR and micro RAMAN spectroscopy. The results are comparable to SiO(2) polytypes such as high disperse silica and opal.

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Section: Resultsmentioning

confidence: 99%

A new attempt to study biomineralised silica bodies in Dactylis glomerata L.

Dietrich

Hemeltjen

Meyer

et al. 2002

Analytical and Bioanalytical Chemistry

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“…This is the case for the direct reduction of silanol groups in fumed silica with hydrogen at 1000 °C 44. 47 The reaction provides a clean hydride modified silica surface. However, according to our experience with other silica materials, the resulting silicon–hydride surface concentration is low and can not be used as a starting material for further surface modification.…”

Section: Introductionmentioning

confidence: 99%

High‐Temperature Chlorination‐Reduction Sequence for the Preparation of Silicon Hydride Modified Silica Surfaces

Plumeré¹,

Speiser²,

Mayer³

et al. 2009

Chemistry A European J

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A general method for the functionalization of silica surfaces with silicon hydride (Si-H) groups is described for four different preparations of silica. The silica surface is reduced in a two-step chlorination-reduction procedure within a simple gas-flow system at high temperatures. After initial dehydroxylation of the silica surface, silicon chloride groups are formed by the reaction with thionyl chloride. The chlorination activates otherwise inaccessible surface siloxane moieties. A high silicon-hydride surface concentration results from the subsequent reduction of the chlorinated surface with hydrogen. The physical properties of the resulting silica are analyzed using scanning electron microscopy, as well as dynamic light scattering and Brunauer-Emmet-Teller measurements. The chlorination-reduction sequence has no significant impact on the structure, surface area and mesopore size of the silica materials used. The surface of the materials is characterized by diffuse reflectance infrared Fourier transform (DRIFT) and (29)Si CP/MAS NMR spectroscopy. The silicon-hydride groups are mostly of the ${{\rm T}{{3\hfill \atop {\rm H}\hfill}}}$-type. The use of high temperatures (>800 degrees C) results in the condensation of internal and surface silanol groups. Therefore, materials with both a fully condensed silica matrix as well as a surface free of silanol groups are obtained. The materials are ideal precursors for further molecular silica surface modification, as demonstrated with a ferrocene derivative.

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“…Afterwards the modification of the disks takes place in a flow reactor. 16 The hydride groups are generated by thermal treatment (1223 K) in a hydrogen stream. This hydrogenation process results in a hydrophobic surface.…”

Section: Sample Preparationmentioning

confidence: 99%