Understanding the twist-bend nematic phase: the characterisation of 1-(4-cyanobiphenyl-4'-yloxy)-6-(4-cyanobiphenyl-4'--yl)hexane (CB6OCB) and comparison with CB7CB

The synthesis and characterisation of the nonsymmetric liquid crystal dimer, 1-(4-cyanobiphenyl-40-yloxy)-6- (4-cyanobiphenyl-40-yl)hexane (CB6OCB) is reported. An enantiotropic nematic (N)–twist-bend nematic (NTB) phase transition is observed at 109 1C and a nematic–isotropic phase transition at 15...

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Autores: Paterson, Daniel A., Gao, Min, Kim, Young-Ki, Robles Hernández, Beatriz, Díez Berart, Sergio|||0000-0002-7241-9009, Salud Puig, Josep|||0000-0002-9359-8122, López Pérez, David Orencio|||0000-0002-9522-8440
Formato: artículo
Fecha de publicación:2016
País:España
Recursos:Universitat Politècnica de Catalunya (UPC)
Repositorio:UPCommons. Portal del coneixement obert de la UPC
Idioma:inglés
OAI Identifier:oai:upcommons.upc.edu:2117/91470
Acesso em linha:https://hdl.handle.net/2117/91470
https://dx.doi.org/10.1039/c6sm00537c
Access Level:acceso abierto
Palavra-chave:Thermodynamics
Transmission electron microscopy
Liquid crystals
Dimers
Hexane
High resolution transmission electron microscopy
Nematic liquid crystals
Nuclear magnetic resonance spectroscopy
Termodinàmica
Microscòpia electrònica de transmissió
Cristalls líquids
Àrees temàtiques de la UPC::Física::Física molecular
Àrees temàtiques de la UPC::Enginyeria química::Química física
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spelling Understanding the twist-bend nematic phase: the characterisation of 1-(4-cyanobiphenyl-4'-yloxy)-6-(4-cyanobiphenyl-4'--yl)hexane (CB6OCB) and comparison with CB7CBPaterson, Daniel A.Gao, MinKim, Young-KiRobles Hernández, BeatrizDíez Berart, Sergio|||0000-0002-7241-9009Salud Puig, Josep|||0000-0002-9359-8122López Pérez, David Orencio|||0000-0002-9522-8440ThermodynamicsTransmission electron microscopyLiquid crystalsDimersHexaneHigh resolution transmission electron microscopyLiquid crystalsNematic liquid crystalsNuclear magnetic resonance spectroscopyTermodinàmicaMicroscòpia electrònica de transmissióCristalls líquidsÀrees temàtiques de la UPC::Física::Física molecularÀrees temàtiques de la UPC::Enginyeria química::Química físicaThe synthesis and characterisation of the nonsymmetric liquid crystal dimer, 1-(4-cyanobiphenyl-40-yloxy)-6- (4-cyanobiphenyl-40-yl)hexane (CB6OCB) is reported. An enantiotropic nematic (N)–twist-bend nematic (NTB) phase transition is observed at 109 1C and a nematic–isotropic phase transition at 153 1C. The NTB phase assignment has been confirmed using polarised light microscopy, freeze fracture transmission electron microscopy (FFTEM), 2H-NMR spectroscopy, and X-ray diffraction. The effective molecular length in both the NTB and N phases indicates a locally intercalated arrangement of the molecules, and the helicoidal pitch length in the NTB phase is estimated to be 8.9 nm. The surface anchoring properties of CB6OCB on a number of aligning layers is reported. A Landau model is applied to describe high-resolution heat capacity measurements in the vicinity of the NTB–N phase transition. Both the theory and heat capacity measurements agree with a very weak first-order phase transition. A complementary extended molecular field theory was found to be in suggestive accord with the 2H-NMR studies of CB6OCB-d2, and those already known for CB7CB-d4. These include the reduced transition temperature, TNTBN/TNI, the order parameter of the mesogenic arms in the N phase close to the NTB–N transition, and the order parameter with respect to the helix axis which is related to the conical angle for the NTB phase.20162016-08-2820162016-11-04journal articlehttp://purl.org/coar/resource_type/c_6501VoRhttp://purl.org/coar/version/c_970fb48d4fbd8a85info:eu-repo/semantics/articleapplication/pdfhttps://hdl.handle.net/2117/91470https://dx.doi.org/10.1039/c6sm00537creponame:UPCommons. Portal del coneixement obert de la UPCinstname:Universitat Politècnica de Catalunya (UPC)Inglésengopen accesshttp://purl.org/coar/access_right/c_abf2http://creativecommons.org/licenses/by-nc-nd/3.0/es/info:eu-repo/semantics/openAccessoai:upcommons.upc.edu:2117/914702026-05-27T15:37:01Z
dc.title.none.fl_str_mv Understanding the twist-bend nematic phase: the characterisation of 1-(4-cyanobiphenyl-4'-yloxy)-6-(4-cyanobiphenyl-4'--yl)hexane (CB6OCB) and comparison with CB7CB
title Understanding the twist-bend nematic phase: the characterisation of 1-(4-cyanobiphenyl-4'-yloxy)-6-(4-cyanobiphenyl-4'--yl)hexane (CB6OCB) and comparison with CB7CB
spellingShingle Understanding the twist-bend nematic phase: the characterisation of 1-(4-cyanobiphenyl-4'-yloxy)-6-(4-cyanobiphenyl-4'--yl)hexane (CB6OCB) and comparison with CB7CB
Paterson, Daniel A.
Thermodynamics
Transmission electron microscopy
Liquid crystals
Dimers
Hexane
High resolution transmission electron microscopy
Liquid crystals
Nematic liquid crystals
Nuclear magnetic resonance spectroscopy
Termodinàmica
Microscòpia electrònica de transmissió
Cristalls líquids
Àrees temàtiques de la UPC::Física::Física molecular
Àrees temàtiques de la UPC::Enginyeria química::Química física
title_short Understanding the twist-bend nematic phase: the characterisation of 1-(4-cyanobiphenyl-4'-yloxy)-6-(4-cyanobiphenyl-4'--yl)hexane (CB6OCB) and comparison with CB7CB
title_full Understanding the twist-bend nematic phase: the characterisation of 1-(4-cyanobiphenyl-4'-yloxy)-6-(4-cyanobiphenyl-4'--yl)hexane (CB6OCB) and comparison with CB7CB
title_fullStr Understanding the twist-bend nematic phase: the characterisation of 1-(4-cyanobiphenyl-4'-yloxy)-6-(4-cyanobiphenyl-4'--yl)hexane (CB6OCB) and comparison with CB7CB
title_full_unstemmed Understanding the twist-bend nematic phase: the characterisation of 1-(4-cyanobiphenyl-4'-yloxy)-6-(4-cyanobiphenyl-4'--yl)hexane (CB6OCB) and comparison with CB7CB
title_sort Understanding the twist-bend nematic phase: the characterisation of 1-(4-cyanobiphenyl-4'-yloxy)-6-(4-cyanobiphenyl-4'--yl)hexane (CB6OCB) and comparison with CB7CB
dc.creator.none.fl_str_mv Paterson, Daniel A.
Gao, Min
Kim, Young-Ki
Robles Hernández, Beatriz
Díez Berart, Sergio|||0000-0002-7241-9009
Salud Puig, Josep|||0000-0002-9359-8122
López Pérez, David Orencio|||0000-0002-9522-8440
author Paterson, Daniel A.
author_facet Paterson, Daniel A.
Gao, Min
Kim, Young-Ki
Robles Hernández, Beatriz
Díez Berart, Sergio|||0000-0002-7241-9009
Salud Puig, Josep|||0000-0002-9359-8122
López Pérez, David Orencio|||0000-0002-9522-8440
author_role author
author2 Gao, Min
Kim, Young-Ki
Robles Hernández, Beatriz
Díez Berart, Sergio|||0000-0002-7241-9009
Salud Puig, Josep|||0000-0002-9359-8122
López Pérez, David Orencio|||0000-0002-9522-8440
author2_role author
author
author
author
author
author
dc.subject.none.fl_str_mv Thermodynamics
Transmission electron microscopy
Liquid crystals
Dimers
Hexane
High resolution transmission electron microscopy
Liquid crystals
Nematic liquid crystals
Nuclear magnetic resonance spectroscopy
Termodinàmica
Microscòpia electrònica de transmissió
Cristalls líquids
Àrees temàtiques de la UPC::Física::Física molecular
Àrees temàtiques de la UPC::Enginyeria química::Química física
topic Thermodynamics
Transmission electron microscopy
Liquid crystals
Dimers
Hexane
High resolution transmission electron microscopy
Liquid crystals
Nematic liquid crystals
Nuclear magnetic resonance spectroscopy
Termodinàmica
Microscòpia electrònica de transmissió
Cristalls líquids
Àrees temàtiques de la UPC::Física::Física molecular
Àrees temàtiques de la UPC::Enginyeria química::Química física
description The synthesis and characterisation of the nonsymmetric liquid crystal dimer, 1-(4-cyanobiphenyl-40-yloxy)-6- (4-cyanobiphenyl-40-yl)hexane (CB6OCB) is reported. An enantiotropic nematic (N)–twist-bend nematic (NTB) phase transition is observed at 109 1C and a nematic–isotropic phase transition at 153 1C. The NTB phase assignment has been confirmed using polarised light microscopy, freeze fracture transmission electron microscopy (FFTEM), 2H-NMR spectroscopy, and X-ray diffraction. The effective molecular length in both the NTB and N phases indicates a locally intercalated arrangement of the molecules, and the helicoidal pitch length in the NTB phase is estimated to be 8.9 nm. The surface anchoring properties of CB6OCB on a number of aligning layers is reported. A Landau model is applied to describe high-resolution heat capacity measurements in the vicinity of the NTB–N phase transition. Both the theory and heat capacity measurements agree with a very weak first-order phase transition. A complementary extended molecular field theory was found to be in suggestive accord with the 2H-NMR studies of CB6OCB-d2, and those already known for CB7CB-d4. These include the reduced transition temperature, TNTBN/TNI, the order parameter of the mesogenic arms in the N phase close to the NTB–N transition, and the order parameter with respect to the helix axis which is related to the conical angle for the NTB phase.
publishDate 2016
dc.date.none.fl_str_mv 2016
2016-08-28
2016
2016-11-04
dc.type.none.fl_str_mv journal article
http://purl.org/coar/resource_type/c_6501
VoR
http://purl.org/coar/version/c_970fb48d4fbd8a85
dc.type.openaire.fl_str_mv info:eu-repo/semantics/article
format article
dc.identifier.none.fl_str_mv https://hdl.handle.net/2117/91470
https://dx.doi.org/10.1039/c6sm00537c
url https://hdl.handle.net/2117/91470
https://dx.doi.org/10.1039/c6sm00537c
dc.language.none.fl_str_mv Inglés
eng
language_invalid_str_mv Inglés
language eng
dc.rights.none.fl_str_mv open access
http://purl.org/coar/access_right/c_abf2

http://creativecommons.org/licenses/by-nc-nd/3.0/es/
dc.rights.openaire.fl_str_mv info:eu-repo/semantics/openAccess
rights_invalid_str_mv open access
http://purl.org/coar/access_right/c_abf2

http://creativecommons.org/licenses/by-nc-nd/3.0/es/
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.source.none.fl_str_mv reponame:UPCommons. Portal del coneixement obert de la UPC
instname:Universitat Politècnica de Catalunya (UPC)
instname_str Universitat Politècnica de Catalunya (UPC)
reponame_str UPCommons. Portal del coneixement obert de la UPC
collection UPCommons. Portal del coneixement obert de la UPC
repository.name.fl_str_mv
repository.mail.fl_str_mv
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score 15,301603

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