1H NMR study of molecular order and dynamics in the liquid crystal CB-C9-CB

Autores
Aluculesei, Alina; Cachitas, Hugo; Carvalho, José; Vaca Chávez Fornasero, Fabián; Figueirinhas, Joaõ L.; Sebastiaõ, Pedro José; Cruz, Carlos; Tamba, Maria Gabriela; Kohlmeier, Alexandra; Mehl, Georg H.
Año de publicación
2019
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
Molecular order and dynamics of the CB-C9-CB liquid crystalline dimer exhibiting the nematic (N) and the twist bend nematic (Ntb) phases were investigated by proton NMR spectroscopy, using fields of 0.78 T and 7.04 T, and relaxometry. The first relaxometry experiments for a very wide Larmor frequency domain (8 kHz-300 MHz) on this system, using a combination of standard and fast field cycling NMR techniques, were performed. The spectroscopy results in the Ntb phase allowed us to probe the local molecular orientation relative to the Ntb helix axis. The relaxation data were analyzed considering order director fluctuations (ODF), molecular self-diffusion (SD) and local molecular rotations/reorientations (R) relaxation mechanisms. Global fits of theoretical relaxation models, as a function of temperature and Larmor frequency, for the phases under investigation, allowed for the determination of rotational correlation times, diffusion coefficients, viscoelastic parameters, correlation lengths and activation energies (in the case of thermally activated mechanisms). A clear difference between the structures of the N and Ntb phases was detected from the results of proton spin-lattice relaxation through distinct temperature and frequency dependencies' signatures of the collective modes. Significant pre-transitional effects were observed at the N-Ntb phase transition both from relaxometry and spectroscopy data. The experimental results correlate to data and models for comparable liquid crystalline systems.
Fil: Aluculesei, Alina. Universidade de Lisboa; Portugal
Fil: Cachitas, Hugo. Universidade de Lisboa; Portugal
Fil: Carvalho, José. Universidade de Lisboa; Portugal
Fil: Vaca Chávez Fornasero, Fabián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina. Universidade de Lisboa; Portugal
Fil: Figueirinhas, Joaõ L.. Universidade de Lisboa; Portugal
Fil: Sebastiaõ, Pedro José. Universidade de Lisboa; Portugal
Fil: Cruz, Carlos. Universidade de Lisboa; Portugal
Fil: Tamba, Maria Gabriela. University of Hull; Reino Unido
Fil: Kohlmeier, Alexandra. University of Hull; Reino Unido
Fil: Mehl, Georg H.. University of Hull; Reino Unido
Materia
NMR
DYNAMICS
LIQUID CRYSTALS
BIAXIAL
Nivel de accesibilidad
acceso abierto
Condiciones de uso
https://creativecommons.org/licenses/by/2.5/ar/
Repositorio
CONICET Digital (CONICET)
Institución
Consejo Nacional de Investigaciones Científicas y Técnicas
OAI Identificador
oai:ri.conicet.gov.ar:11336/124393
Acceder
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oai_identifier_str oai:ri.conicet.gov.ar:11336/124393
network_acronym_str CONICETDig
repository_id_str 3498
network_name_str CONICET Digital (CONICET)
spelling 1H NMR study of molecular order and dynamics in the liquid crystal CB-C9-CBAluculesei, AlinaCachitas, HugoCarvalho, JoséVaca Chávez Fornasero, FabiánFigueirinhas, Joaõ L.Sebastiaõ, Pedro JoséCruz, CarlosTamba, Maria GabrielaKohlmeier, AlexandraMehl, Georg H.NMRDYNAMICSLIQUID CRYSTALSBIAXIALhttps://purl.org/becyt/ford/1.3https://purl.org/becyt/ford/1Molecular order and dynamics of the CB-C9-CB liquid crystalline dimer exhibiting the nematic (N) and the twist bend nematic (Ntb) phases were investigated by proton NMR spectroscopy, using fields of 0.78 T and 7.04 T, and relaxometry. The first relaxometry experiments for a very wide Larmor frequency domain (8 kHz-300 MHz) on this system, using a combination of standard and fast field cycling NMR techniques, were performed. The spectroscopy results in the Ntb phase allowed us to probe the local molecular orientation relative to the Ntb helix axis. The relaxation data were analyzed considering order director fluctuations (ODF), molecular self-diffusion (SD) and local molecular rotations/reorientations (R) relaxation mechanisms. Global fits of theoretical relaxation models, as a function of temperature and Larmor frequency, for the phases under investigation, allowed for the determination of rotational correlation times, diffusion coefficients, viscoelastic parameters, correlation lengths and activation energies (in the case of thermally activated mechanisms). A clear difference between the structures of the N and Ntb phases was detected from the results of proton spin-lattice relaxation through distinct temperature and frequency dependencies' signatures of the collective modes. Significant pre-transitional effects were observed at the N-Ntb phase transition both from relaxometry and spectroscopy data. The experimental results correlate to data and models for comparable liquid crystalline systems.Fil: Aluculesei, Alina. Universidade de Lisboa; PortugalFil: Cachitas, Hugo. Universidade de Lisboa; PortugalFil: Carvalho, José. Universidade de Lisboa; PortugalFil: Vaca Chávez Fornasero, Fabián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina. Universidade de Lisboa; PortugalFil: Figueirinhas, Joaõ L.. Universidade de Lisboa; PortugalFil: Sebastiaõ, Pedro José. Universidade de Lisboa; PortugalFil: Cruz, Carlos. Universidade de Lisboa; PortugalFil: Tamba, Maria Gabriela. University of Hull; Reino UnidoFil: Kohlmeier, Alexandra. University of Hull; Reino UnidoFil: Mehl, Georg H.. University of Hull; Reino UnidoRoyal Society of Chemistry2019-10info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionhttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdfapplication/pdfhttp://hdl.handle.net/11336/124393Aluculesei, Alina; Cachitas, Hugo; Carvalho, José; Vaca Chávez Fornasero, Fabián; Figueirinhas, Joaõ L.; et al.; 1H NMR study of molecular order and dynamics in the liquid crystal CB-C9-CB; Royal Society of Chemistry; Physical Chemistry Chemical Physics; 21; 8; 10-2019; 4523-45371463-9076CONICET DigitalCONICETenginfo:eu-repo/semantics/altIdentifier/url/https://pubs.rsc.org/en/content/articlelanding/2019/cp/c8cp06868b#!divAbstractinfo:eu-repo/semantics/altIdentifier/doi/10.1039/c8cp06868binfo:eu-repo/semantics/openAccesshttps://creativecommons.org/licenses/by/2.5/ar/reponame:CONICET Digital (CONICET)instname:Consejo Nacional de Investigaciones Científicas y Técnicas2025-09-29T09:38:08Zoai:ri.conicet.gov.ar:11336/124393instacron:CONICETInstitucionalhttp://ri.conicet.gov.ar/Organismo científico-tecnológicoNo correspondehttp://ri.conicet.gov.ar/oai/requestdasensio@conicet.gov.ar; lcarlino@conicet.gov.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:34982025-09-29 09:38:08.863CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicasfalse
dc.title.none.fl_str_mv 1H NMR study of molecular order and dynamics in the liquid crystal CB-C9-CB
title 1H NMR study of molecular order and dynamics in the liquid crystal CB-C9-CB
spellingShingle 1H NMR study of molecular order and dynamics in the liquid crystal CB-C9-CB
Aluculesei, Alina
NMR
DYNAMICS
LIQUID CRYSTALS
BIAXIAL
title_short 1H NMR study of molecular order and dynamics in the liquid crystal CB-C9-CB
title_full 1H NMR study of molecular order and dynamics in the liquid crystal CB-C9-CB
title_fullStr 1H NMR study of molecular order and dynamics in the liquid crystal CB-C9-CB
title_full_unstemmed 1H NMR study of molecular order and dynamics in the liquid crystal CB-C9-CB
title_sort 1H NMR study of molecular order and dynamics in the liquid crystal CB-C9-CB
dc.creator.none.fl_str_mv Aluculesei, Alina
Cachitas, Hugo
Carvalho, José
Vaca Chávez Fornasero, Fabián
Figueirinhas, Joaõ L.
Sebastiaõ, Pedro José
Cruz, Carlos
Tamba, Maria Gabriela
Kohlmeier, Alexandra
Mehl, Georg H.
author Aluculesei, Alina
author_facet Aluculesei, Alina
Cachitas, Hugo
Carvalho, José
Vaca Chávez Fornasero, Fabián
Figueirinhas, Joaõ L.
Sebastiaõ, Pedro José
Cruz, Carlos
Tamba, Maria Gabriela
Kohlmeier, Alexandra
Mehl, Georg H.
author_role author
author2 Cachitas, Hugo
Carvalho, José
Vaca Chávez Fornasero, Fabián
Figueirinhas, Joaõ L.
Sebastiaõ, Pedro José
Cruz, Carlos
Tamba, Maria Gabriela
Kohlmeier, Alexandra
Mehl, Georg H.
author2_role author
author
author
author
author
author
author
author
author
dc.subject.none.fl_str_mv NMR
DYNAMICS
LIQUID CRYSTALS
BIAXIAL
topic NMR
DYNAMICS
LIQUID CRYSTALS
BIAXIAL
purl_subject.fl_str_mv https://purl.org/becyt/ford/1.3
https://purl.org/becyt/ford/1
dc.description.none.fl_txt_mv Molecular order and dynamics of the CB-C9-CB liquid crystalline dimer exhibiting the nematic (N) and the twist bend nematic (Ntb) phases were investigated by proton NMR spectroscopy, using fields of 0.78 T and 7.04 T, and relaxometry. The first relaxometry experiments for a very wide Larmor frequency domain (8 kHz-300 MHz) on this system, using a combination of standard and fast field cycling NMR techniques, were performed. The spectroscopy results in the Ntb phase allowed us to probe the local molecular orientation relative to the Ntb helix axis. The relaxation data were analyzed considering order director fluctuations (ODF), molecular self-diffusion (SD) and local molecular rotations/reorientations (R) relaxation mechanisms. Global fits of theoretical relaxation models, as a function of temperature and Larmor frequency, for the phases under investigation, allowed for the determination of rotational correlation times, diffusion coefficients, viscoelastic parameters, correlation lengths and activation energies (in the case of thermally activated mechanisms). A clear difference between the structures of the N and Ntb phases was detected from the results of proton spin-lattice relaxation through distinct temperature and frequency dependencies' signatures of the collective modes. Significant pre-transitional effects were observed at the N-Ntb phase transition both from relaxometry and spectroscopy data. The experimental results correlate to data and models for comparable liquid crystalline systems.
Fil: Aluculesei, Alina. Universidade de Lisboa; Portugal
Fil: Cachitas, Hugo. Universidade de Lisboa; Portugal
Fil: Carvalho, José. Universidade de Lisboa; Portugal
Fil: Vaca Chávez Fornasero, Fabián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina. Universidade de Lisboa; Portugal
Fil: Figueirinhas, Joaõ L.. Universidade de Lisboa; Portugal
Fil: Sebastiaõ, Pedro José. Universidade de Lisboa; Portugal
Fil: Cruz, Carlos. Universidade de Lisboa; Portugal
Fil: Tamba, Maria Gabriela. University of Hull; Reino Unido
Fil: Kohlmeier, Alexandra. University of Hull; Reino Unido
Fil: Mehl, Georg H.. University of Hull; Reino Unido
description Molecular order and dynamics of the CB-C9-CB liquid crystalline dimer exhibiting the nematic (N) and the twist bend nematic (Ntb) phases were investigated by proton NMR spectroscopy, using fields of 0.78 T and 7.04 T, and relaxometry. The first relaxometry experiments for a very wide Larmor frequency domain (8 kHz-300 MHz) on this system, using a combination of standard and fast field cycling NMR techniques, were performed. The spectroscopy results in the Ntb phase allowed us to probe the local molecular orientation relative to the Ntb helix axis. The relaxation data were analyzed considering order director fluctuations (ODF), molecular self-diffusion (SD) and local molecular rotations/reorientations (R) relaxation mechanisms. Global fits of theoretical relaxation models, as a function of temperature and Larmor frequency, for the phases under investigation, allowed for the determination of rotational correlation times, diffusion coefficients, viscoelastic parameters, correlation lengths and activation energies (in the case of thermally activated mechanisms). A clear difference between the structures of the N and Ntb phases was detected from the results of proton spin-lattice relaxation through distinct temperature and frequency dependencies' signatures of the collective modes. Significant pre-transitional effects were observed at the N-Ntb phase transition both from relaxometry and spectroscopy data. The experimental results correlate to data and models for comparable liquid crystalline systems.
publishDate 2019
dc.date.none.fl_str_mv 2019-10
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
http://purl.org/coar/resource_type/c_6501
info:ar-repo/semantics/articulo
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv http://hdl.handle.net/11336/124393
Aluculesei, Alina; Cachitas, Hugo; Carvalho, José; Vaca Chávez Fornasero, Fabián; Figueirinhas, Joaõ L.; et al.; 1H NMR study of molecular order and dynamics in the liquid crystal CB-C9-CB; Royal Society of Chemistry; Physical Chemistry Chemical Physics; 21; 8; 10-2019; 4523-4537
1463-9076
CONICET Digital
CONICET
url http://hdl.handle.net/11336/124393
identifier_str_mv Aluculesei, Alina; Cachitas, Hugo; Carvalho, José; Vaca Chávez Fornasero, Fabián; Figueirinhas, Joaõ L.; et al.; 1H NMR study of molecular order and dynamics in the liquid crystal CB-C9-CB; Royal Society of Chemistry; Physical Chemistry Chemical Physics; 21; 8; 10-2019; 4523-4537
1463-9076
CONICET Digital
CONICET
dc.language.none.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv info:eu-repo/semantics/altIdentifier/url/https://pubs.rsc.org/en/content/articlelanding/2019/cp/c8cp06868b#!divAbstract
info:eu-repo/semantics/altIdentifier/doi/10.1039/c8cp06868b
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
https://creativecommons.org/licenses/by/2.5/ar/
eu_rights_str_mv openAccess
rights_invalid_str_mv https://creativecommons.org/licenses/by/2.5/ar/
dc.format.none.fl_str_mv application/pdf
application/pdf
dc.publisher.none.fl_str_mv Royal Society of Chemistry
publisher.none.fl_str_mv Royal Society of Chemistry
dc.source.none.fl_str_mv reponame:CONICET Digital (CONICET)
instname:Consejo Nacional de Investigaciones Científicas y Técnicas
reponame_str CONICET Digital (CONICET)
collection CONICET Digital (CONICET)
instname_str Consejo Nacional de Investigaciones Científicas y Técnicas
repository.name.fl_str_mv CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicas
repository.mail.fl_str_mv dasensio@conicet.gov.ar; lcarlino@conicet.gov.ar
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score 13.069144

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