Nanostructured sonogels

Acoustic cavitation effects in sol-gel liquid processing permits to obtain nanostructured materials, with size-dependent properties. The so-called "hot spots" produce very high temperatures and pressures which act as nanoreactors. Ultrasounds force the dissolution and the reaction stars. T...

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Detalles Bibliográficos
Autores: Rosa Fox, Nicolás de la, Morales Flórez, Víctor, Piñero, Manuel, Esquivias Fedriani, Luis María
Tipo de recurso: artículo
Estado:Versión enviada para evaluación y publicación
Fecha de publicación:2009
País:España
Institución:Universidad de Sevilla (US)
Repositorio:idUS. Depósito de Investigación de la Universidad de Sevilla
OAI Identifier:oai:idus.us.es:11441/95173
Acceso en línea:https://hdl.handle.net/11441/95173
Access Level:acceso abierto
Palabra clave:Aerogel
Gel
Precipitate
Sol
Solution
Sonogel
Xerogel
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spelling Nanostructured sonogelsRosa Fox, Nicolás de laMorales Flórez, VíctorPiñero, ManuelEsquivias Fedriani, Luis MaríaAerogelGelPrecipitateSolSolutionSonogelXerogelAcoustic cavitation effects in sol-gel liquid processing permits to obtain nanostructured materials, with size-dependent properties. The so-called "hot spots" produce very high temperatures and pressures which act as nanoreactors. Ultrasounds force the dissolution and the reaction stars. The products (alcohol, water and silanol) help to continue the dissolution, being catalyst content, temperature bath and alkyl group length dependent. Popular choices used in the preparation of silica-based gels are tetramethoxysilane (TMOS), Si(OCH3)4 and tetraethoxysilane (TEOS), Si(OC 2H5)4. The resultant "sonogels" are denser gels with finer and homogeneous porosity than those of classic ones. They have a high surface/volume ratio and are built by small particles (1 nm radius) and a high cross-linked network with low -OH surface coverage radicals. In this way a cluster model is presented based on randomly-packed spheres in several hierarchical levels that represent the real sonoaerogel. Organic modified silicates (ORMOSIL) were obtained by supercritical drying in ethanol of the corresponding alcogel producing a hybrid organic/inorganic aerogel. The new material takes the advantages of the organic polymers as flexibility, low density, toughness and formability whereas the inorganic part contributes with surface hardness, modulus strength, transparency and high refractive index. The sonocatalytic method has proven to be adequate to prepare silica matrices for fine and uniform dispersion of CdS and PbS quantum dots (QDs), which show exciton quantum confinement. We present results of characterization of these materials, such as nitrogen physisorption, small angle X-ray/neutrons scattering, electron microscopy, uniaxial compression and nanoindentation. Finally these materials find application as biomaterials for tissue engineering and for CO2 sequestration by means the carbonation reaction.Ministerio de Ciencia y Tecnología MAT2005-1583Trans Tech Publications LtdFísica de la Materia Condensada2009info:eu-repo/semantics/articleinfo:eu-repo/semantics/submittedVersionapplication/pdfapplication/pdfhttps://hdl.handle.net/11441/95173reponame:idUS. Depósito de Investigación de la Universidad de Sevillainstname:Universidad de Sevilla (US)InglésKey Engineering Materials, 391, 45-78.MAT2005-1583info:eu-repo/semantics/openAccessoai:idus.us.es:11441/951732026-06-17T12:51:07Z
dc.title.none.fl_str_mv Nanostructured sonogels
title Nanostructured sonogels
spellingShingle Nanostructured sonogels
Rosa Fox, Nicolás de la
Aerogel
Gel
Precipitate
Sol
Solution
Sonogel
Xerogel
title_short Nanostructured sonogels
title_full Nanostructured sonogels
title_fullStr Nanostructured sonogels
title_full_unstemmed Nanostructured sonogels
title_sort Nanostructured sonogels
dc.creator.none.fl_str_mv Rosa Fox, Nicolás de la
Morales Flórez, Víctor
Piñero, Manuel
Esquivias Fedriani, Luis María
author Rosa Fox, Nicolás de la
author_facet Rosa Fox, Nicolás de la
Morales Flórez, Víctor
Piñero, Manuel
Esquivias Fedriani, Luis María
author_role author
author2 Morales Flórez, Víctor
Piñero, Manuel
Esquivias Fedriani, Luis María
author2_role author
author
author
dc.contributor.none.fl_str_mv Física de la Materia Condensada
dc.subject.none.fl_str_mv Aerogel
Gel
Precipitate
Sol
Solution
Sonogel
Xerogel
topic Aerogel
Gel
Precipitate
Sol
Solution
Sonogel
Xerogel
description Acoustic cavitation effects in sol-gel liquid processing permits to obtain nanostructured materials, with size-dependent properties. The so-called "hot spots" produce very high temperatures and pressures which act as nanoreactors. Ultrasounds force the dissolution and the reaction stars. The products (alcohol, water and silanol) help to continue the dissolution, being catalyst content, temperature bath and alkyl group length dependent. Popular choices used in the preparation of silica-based gels are tetramethoxysilane (TMOS), Si(OCH3)4 and tetraethoxysilane (TEOS), Si(OC 2H5)4. The resultant "sonogels" are denser gels with finer and homogeneous porosity than those of classic ones. They have a high surface/volume ratio and are built by small particles (1 nm radius) and a high cross-linked network with low -OH surface coverage radicals. In this way a cluster model is presented based on randomly-packed spheres in several hierarchical levels that represent the real sonoaerogel. Organic modified silicates (ORMOSIL) were obtained by supercritical drying in ethanol of the corresponding alcogel producing a hybrid organic/inorganic aerogel. The new material takes the advantages of the organic polymers as flexibility, low density, toughness and formability whereas the inorganic part contributes with surface hardness, modulus strength, transparency and high refractive index. The sonocatalytic method has proven to be adequate to prepare silica matrices for fine and uniform dispersion of CdS and PbS quantum dots (QDs), which show exciton quantum confinement. We present results of characterization of these materials, such as nitrogen physisorption, small angle X-ray/neutrons scattering, electron microscopy, uniaxial compression and nanoindentation. Finally these materials find application as biomaterials for tissue engineering and for CO2 sequestration by means the carbonation reaction.
publishDate 2009
dc.date.none.fl_str_mv 2009
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/submittedVersion
format article
status_str submittedVersion
dc.identifier.none.fl_str_mv https://hdl.handle.net/11441/95173
url https://hdl.handle.net/11441/95173
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv Key Engineering Materials, 391, 45-78.
MAT2005-1583
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
application/pdf
dc.publisher.none.fl_str_mv Trans Tech Publications Ltd
publisher.none.fl_str_mv Trans Tech Publications Ltd
dc.source.none.fl_str_mv reponame:idUS. Depósito de Investigación de la Universidad de Sevilla
instname:Universidad de Sevilla (US)
instname_str Universidad de Sevilla (US)
reponame_str idUS. Depósito de Investigación de la Universidad de Sevilla
collection idUS. Depósito de Investigación de la Universidad de Sevilla
repository.name.fl_str_mv
repository.mail.fl_str_mv
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score 15,300724

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