Smectic A: cholesteric phase transition investigated by small angle X-ray diffraction and viscosity measurements
Autor(a) principal: | |
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Data de Publicação: | 2002 |
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=S0103-97332002000300007 |
Resumo: | We have studied the in influence of the mean molecular length on the nature of the cholesteric (N*) smectic A (A) liquid crystal phase transition for thermotropic compounds of cholesteryl myristate (C14), cholesteryl nonanoate (C9), and binary mixtures of C14 C9 and cholesteryl caproate (C6) phase (dA), the mean molecular length (<img src="http:/img/fbpe/bjp/v32n2b/07eq01.gif">) in the N* domain, and the correlation length (epsilon), as well as changes along the N* A phase transition, were determined from the X-ray diffraction data. The results show a decrease in A phase domain and an expansion of the N* domain as the mean molecular length is diminished. Such effect induces a second order A N* phase transition for a particular mixture of 63.1 mol% of C9 and 36.9 mol% of C6, evidenced by viscosity measurements in good agreement with previous density data. |
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Brazilian Journal of Physics |
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spelling |
Smectic A: cholesteric phase transition investigated by small angle X-ray diffraction and viscosity measurementsWe have studied the in influence of the mean molecular length on the nature of the cholesteric (N*) smectic A (A) liquid crystal phase transition for thermotropic compounds of cholesteryl myristate (C14), cholesteryl nonanoate (C9), and binary mixtures of C14 C9 and cholesteryl caproate (C6) phase (dA), the mean molecular length (<img src="http:/img/fbpe/bjp/v32n2b/07eq01.gif">) in the N* domain, and the correlation length (epsilon), as well as changes along the N* A phase transition, were determined from the X-ray diffraction data. The results show a decrease in A phase domain and an expansion of the N* domain as the mean molecular length is diminished. Such effect induces a second order A N* phase transition for a particular mixture of 63.1 mol% of C9 and 36.9 mol% of C6, evidenced by viscosity measurements in good agreement with previous density data.Sociedade Brasileira de Física2002-06-01info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersiontext/htmlhttp://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-97332002000300007Brazilian Journal of Physics v.32 n.2b 2002reponame:Brazilian Journal of Physicsinstname:Sociedade Brasileira de Física (SBF)instacron:SBF10.1590/S0103-97332002000300007info:eu-repo/semantics/openAccessDuarte,E. L.Itri,R.Sampaio,A. R.Simões,M.Palangana,A. J.eng2002-11-20T00:00:00Zoai:scielo:S0103-97332002000300007Revistahttp://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:2002-11-20T00:00Brazilian Journal of Physics - Sociedade Brasileira de Física (SBF)false |
dc.title.none.fl_str_mv |
Smectic A: cholesteric phase transition investigated by small angle X-ray diffraction and viscosity measurements |
title |
Smectic A: cholesteric phase transition investigated by small angle X-ray diffraction and viscosity measurements |
spellingShingle |
Smectic A: cholesteric phase transition investigated by small angle X-ray diffraction and viscosity measurements Duarte,E. L. |
title_short |
Smectic A: cholesteric phase transition investigated by small angle X-ray diffraction and viscosity measurements |
title_full |
Smectic A: cholesteric phase transition investigated by small angle X-ray diffraction and viscosity measurements |
title_fullStr |
Smectic A: cholesteric phase transition investigated by small angle X-ray diffraction and viscosity measurements |
title_full_unstemmed |
Smectic A: cholesteric phase transition investigated by small angle X-ray diffraction and viscosity measurements |
title_sort |
Smectic A: cholesteric phase transition investigated by small angle X-ray diffraction and viscosity measurements |
author |
Duarte,E. L. |
author_facet |
Duarte,E. L. Itri,R. Sampaio,A. R. Simões,M. Palangana,A. J. |
author_role |
author |
author2 |
Itri,R. Sampaio,A. R. Simões,M. Palangana,A. J. |
author2_role |
author author author author |
dc.contributor.author.fl_str_mv |
Duarte,E. L. Itri,R. Sampaio,A. R. Simões,M. Palangana,A. J. |
description |
We have studied the in influence of the mean molecular length on the nature of the cholesteric (N*) smectic A (A) liquid crystal phase transition for thermotropic compounds of cholesteryl myristate (C14), cholesteryl nonanoate (C9), and binary mixtures of C14 C9 and cholesteryl caproate (C6) phase (dA), the mean molecular length (<img src="http:/img/fbpe/bjp/v32n2b/07eq01.gif">) in the N* domain, and the correlation length (epsilon), as well as changes along the N* A phase transition, were determined from the X-ray diffraction data. The results show a decrease in A phase domain and an expansion of the N* domain as the mean molecular length is diminished. Such effect induces a second order A N* phase transition for a particular mixture of 63.1 mol% of C9 and 36.9 mol% of C6, evidenced by viscosity measurements in good agreement with previous density data. |
publishDate |
2002 |
dc.date.none.fl_str_mv |
2002-06-01 |
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=S0103-97332002000300007 |
url |
http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-97332002000300007 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
10.1590/S0103-97332002000300007 |
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.32 n.2b 2002 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_ |
1754734859809456128 |