Osmotic stress on concentrated colloidal suspensions: a path towards equilibrium?
Autor(a) principal: | |
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Data de Publicação: | 2009 |
Outros Autores: | , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Brazilian Journal of Physics |
Texto Completo: | http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-97332009000200006 |
Resumo: | We discuss in this study the advantages and limitations of the osmotic stress method that enables to set the osmotic pressure to a given system. By investigating aqueous suspension of monodisperse silica nanoparticles of radius 78 at an ionic strength of 10-2 mol/L, we show that the method is very accurate to probe the phase behavior of colloidal suspensions because it allows to prepare samples all along the equation of state of the system at constant ionic strength without any aggregation and with a well defined structure, as shown by Small-Angle Neutron Scattering (SANS) experiments. However the method fails to yield crystalline structures, since solid samples obtained are always glassy, even when the fluid-solid transition is crossed with small successive jumps of 1000 Pa. This phenomenon comes from the kinetics of the process which exhibits in our experimental conditions an exponential decay time with a characteristic time of ≈ 3 hours that induces a very strong change of the volume fraction of the suspension in the early stages of the stress. When the jump of pressure is very important, the system is frozen in the vicinity of the dialysis bag and forms a dense shell that eventually prevents some spatial regions of the sample to reach equilibrium. In this case, the osmotic stress forces the sample to get a structure very spatially heterogeneous at macroscopic scale. |
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Brazilian Journal of Physics |
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Osmotic stress on concentrated colloidal suspensions: a path towards equilibrium?osmotic stresscolloidal suspensionsSANSWe discuss in this study the advantages and limitations of the osmotic stress method that enables to set the osmotic pressure to a given system. By investigating aqueous suspension of monodisperse silica nanoparticles of radius 78 at an ionic strength of 10-2 mol/L, we show that the method is very accurate to probe the phase behavior of colloidal suspensions because it allows to prepare samples all along the equation of state of the system at constant ionic strength without any aggregation and with a well defined structure, as shown by Small-Angle Neutron Scattering (SANS) experiments. However the method fails to yield crystalline structures, since solid samples obtained are always glassy, even when the fluid-solid transition is crossed with small successive jumps of 1000 Pa. This phenomenon comes from the kinetics of the process which exhibits in our experimental conditions an exponential decay time with a characteristic time of ≈ 3 hours that induces a very strong change of the volume fraction of the suspension in the early stages of the stress. When the jump of pressure is very important, the system is frozen in the vicinity of the dialysis bag and forms a dense shell that eventually prevents some spatial regions of the sample to reach equilibrium. In this case, the osmotic stress forces the sample to get a structure very spatially heterogeneous at macroscopic scale.Sociedade Brasileira de Física2009-04-01info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersiontext/htmlhttp://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-97332009000200006Brazilian Journal of Physics v.39 n.1a 2009reponame:Brazilian Journal of Physicsinstname:Sociedade Brasileira de Física (SBF)instacron:SBF10.1590/S0103-97332009000200006info:eu-repo/semantics/openAccessRobbes,A.S.Cousin,F.Mériguet,G.eng2009-07-03T00:00:00Zoai:scielo:S0103-97332009000200006Revistahttp://www.sbfisica.org.br/v1/home/index.php/pt/ONGhttps://old.scielo.br/oai/scielo-oai.phpsbfisica@sbfisica.org.br||sbfisica@sbfisica.org.br1678-44480103-9733opendoar:2009-07-03T00:00Brazilian Journal of Physics - Sociedade Brasileira de Física (SBF)false |
dc.title.none.fl_str_mv |
Osmotic stress on concentrated colloidal suspensions: a path towards equilibrium? |
title |
Osmotic stress on concentrated colloidal suspensions: a path towards equilibrium? |
spellingShingle |
Osmotic stress on concentrated colloidal suspensions: a path towards equilibrium? Robbes,A.S. osmotic stress colloidal suspensions SANS |
title_short |
Osmotic stress on concentrated colloidal suspensions: a path towards equilibrium? |
title_full |
Osmotic stress on concentrated colloidal suspensions: a path towards equilibrium? |
title_fullStr |
Osmotic stress on concentrated colloidal suspensions: a path towards equilibrium? |
title_full_unstemmed |
Osmotic stress on concentrated colloidal suspensions: a path towards equilibrium? |
title_sort |
Osmotic stress on concentrated colloidal suspensions: a path towards equilibrium? |
author |
Robbes,A.S. |
author_facet |
Robbes,A.S. Cousin,F. Mériguet,G. |
author_role |
author |
author2 |
Cousin,F. Mériguet,G. |
author2_role |
author author |
dc.contributor.author.fl_str_mv |
Robbes,A.S. Cousin,F. Mériguet,G. |
dc.subject.por.fl_str_mv |
osmotic stress colloidal suspensions SANS |
topic |
osmotic stress colloidal suspensions SANS |
description |
We discuss in this study the advantages and limitations of the osmotic stress method that enables to set the osmotic pressure to a given system. By investigating aqueous suspension of monodisperse silica nanoparticles of radius 78 at an ionic strength of 10-2 mol/L, we show that the method is very accurate to probe the phase behavior of colloidal suspensions because it allows to prepare samples all along the equation of state of the system at constant ionic strength without any aggregation and with a well defined structure, as shown by Small-Angle Neutron Scattering (SANS) experiments. However the method fails to yield crystalline structures, since solid samples obtained are always glassy, even when the fluid-solid transition is crossed with small successive jumps of 1000 Pa. This phenomenon comes from the kinetics of the process which exhibits in our experimental conditions an exponential decay time with a characteristic time of ≈ 3 hours that induces a very strong change of the volume fraction of the suspension in the early stages of the stress. When the jump of pressure is very important, the system is frozen in the vicinity of the dialysis bag and forms a dense shell that eventually prevents some spatial regions of the sample to reach equilibrium. In this case, the osmotic stress forces the sample to get a structure very spatially heterogeneous at macroscopic scale. |
publishDate |
2009 |
dc.date.none.fl_str_mv |
2009-04-01 |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-97332009000200006 |
url |
http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-97332009000200006 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
10.1590/S0103-97332009000200006 |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
text/html |
dc.publisher.none.fl_str_mv |
Sociedade Brasileira de Física |
publisher.none.fl_str_mv |
Sociedade Brasileira de Física |
dc.source.none.fl_str_mv |
Brazilian Journal of Physics v.39 n.1a 2009 reponame:Brazilian Journal of Physics instname:Sociedade Brasileira de Física (SBF) instacron:SBF |
instname_str |
Sociedade Brasileira de Física (SBF) |
instacron_str |
SBF |
institution |
SBF |
reponame_str |
Brazilian Journal of Physics |
collection |
Brazilian Journal of Physics |
repository.name.fl_str_mv |
Brazilian Journal of Physics - Sociedade Brasileira de Física (SBF) |
repository.mail.fl_str_mv |
sbfisica@sbfisica.org.br||sbfisica@sbfisica.org.br |
_version_ |
1754734864803823616 |