Core-and-shell nature of Stöber silica particles

Detalhes bibliográficos
Autor(a) principal: Leite,Carlos A. P.
Data de Publicação: 2001
Outros Autores: Souza,Elizabeth F. de, Galembeck,Fernando
Tipo de documento: Artigo
Idioma: eng
Título da fonte: Journal of the Brazilian Chemical Society (Online)
Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532001000400013
Resumo: Two different samples of monodisperse Stöber silica particles were examined in the analytical transmission electron microscope, using different imaging modes: bright-field, dark-field, energy-loss and elemental distribution maps. The particles (effective diameters = 141 and 36 nm) are formed by domains of variable O/Si ratio, which is consistent with a variable degree of hydration, and they coexist with particles with a high O/Si ratio measuring a few nanometers only, which appear dispersed in the picture background. Bright-field and energy-loss images of the larger particles show a core-and-shell morphology, and the shells have a higher amount of high-O/Si domains as well as contaminating carbon compounds. On the other hand, the smaller particles (effective diameter = 36 nm) are also formed by distinct domains, but their morphology is neither spherical or core-and-shell. The mechanisms for particle formation presented in the literature are discussed, considering the present findings.
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spelling Core-and-shell nature of Stöber silica particlescolloidal silicatransmission electron microscopyenergy-filtered imagingsilica particle microchemistryTwo different samples of monodisperse Stöber silica particles were examined in the analytical transmission electron microscope, using different imaging modes: bright-field, dark-field, energy-loss and elemental distribution maps. The particles (effective diameters = 141 and 36 nm) are formed by domains of variable O/Si ratio, which is consistent with a variable degree of hydration, and they coexist with particles with a high O/Si ratio measuring a few nanometers only, which appear dispersed in the picture background. Bright-field and energy-loss images of the larger particles show a core-and-shell morphology, and the shells have a higher amount of high-O/Si domains as well as contaminating carbon compounds. On the other hand, the smaller particles (effective diameter = 36 nm) are also formed by distinct domains, but their morphology is neither spherical or core-and-shell. The mechanisms for particle formation presented in the literature are discussed, considering the present findings.Sociedade Brasileira de Química2001-08-01info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersiontext/htmlhttp://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532001000400013Journal of the Brazilian Chemical Society v.12 n.4 2001reponame:Journal of the Brazilian Chemical Society (Online)instname:Sociedade Brasileira de Química (SBQ)instacron:SBQ10.1590/S0103-50532001000400013info:eu-repo/semantics/openAccessLeite,Carlos A. P.Souza,Elizabeth F. deGalembeck,Fernandoeng2001-10-17T00:00:00Zoai:scielo:S0103-50532001000400013Revistahttp://jbcs.sbq.org.brONGhttps://old.scielo.br/oai/scielo-oai.php||office@jbcs.sbq.org.br1678-47900103-5053opendoar:2001-10-17T00:00Journal of the Brazilian Chemical Society (Online) - Sociedade Brasileira de Química (SBQ)false
dc.title.none.fl_str_mv Core-and-shell nature of Stöber silica particles
title Core-and-shell nature of Stöber silica particles
spellingShingle Core-and-shell nature of Stöber silica particles
Leite,Carlos A. P.
colloidal silica
transmission electron microscopy
energy-filtered imaging
silica particle microchemistry
title_short Core-and-shell nature of Stöber silica particles
title_full Core-and-shell nature of Stöber silica particles
title_fullStr Core-and-shell nature of Stöber silica particles
title_full_unstemmed Core-and-shell nature of Stöber silica particles
title_sort Core-and-shell nature of Stöber silica particles
author Leite,Carlos A. P.
author_facet Leite,Carlos A. P.
Souza,Elizabeth F. de
Galembeck,Fernando
author_role author
author2 Souza,Elizabeth F. de
Galembeck,Fernando
author2_role author
author
dc.contributor.author.fl_str_mv Leite,Carlos A. P.
Souza,Elizabeth F. de
Galembeck,Fernando
dc.subject.por.fl_str_mv colloidal silica
transmission electron microscopy
energy-filtered imaging
silica particle microchemistry
topic colloidal silica
transmission electron microscopy
energy-filtered imaging
silica particle microchemistry
description Two different samples of monodisperse Stöber silica particles were examined in the analytical transmission electron microscope, using different imaging modes: bright-field, dark-field, energy-loss and elemental distribution maps. The particles (effective diameters = 141 and 36 nm) are formed by domains of variable O/Si ratio, which is consistent with a variable degree of hydration, and they coexist with particles with a high O/Si ratio measuring a few nanometers only, which appear dispersed in the picture background. Bright-field and energy-loss images of the larger particles show a core-and-shell morphology, and the shells have a higher amount of high-O/Si domains as well as contaminating carbon compounds. On the other hand, the smaller particles (effective diameter = 36 nm) are also formed by distinct domains, but their morphology is neither spherical or core-and-shell. The mechanisms for particle formation presented in the literature are discussed, considering the present findings.
publishDate 2001
dc.date.none.fl_str_mv 2001-08-01
dc.type.driver.fl_str_mv info:eu-repo/semantics/article
dc.type.status.fl_str_mv info:eu-repo/semantics/publishedVersion
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dc.identifier.uri.fl_str_mv http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532001000400013
url http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532001000400013
dc.language.iso.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv 10.1590/S0103-50532001000400013
dc.rights.driver.fl_str_mv info:eu-repo/semantics/openAccess
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dc.format.none.fl_str_mv text/html
dc.publisher.none.fl_str_mv Sociedade Brasileira de Química
publisher.none.fl_str_mv Sociedade Brasileira de Química
dc.source.none.fl_str_mv Journal of the Brazilian Chemical Society v.12 n.4 2001
reponame:Journal of the Brazilian Chemical Society (Online)
instname:Sociedade Brasileira de Química (SBQ)
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instname_str Sociedade Brasileira de Química (SBQ)
instacron_str SBQ
institution SBQ
reponame_str Journal of the Brazilian Chemical Society (Online)
collection Journal of the Brazilian Chemical Society (Online)
repository.name.fl_str_mv Journal of the Brazilian Chemical Society (Online) - Sociedade Brasileira de Química (SBQ)
repository.mail.fl_str_mv ||office@jbcs.sbq.org.br
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