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Dielectric Study of Liquid Crystal Dimers: Probing the Orientational Order and Molecular Interactions in Nematic and Twist-Bend Nematic Phases
[Image: see text] Dielectric spectroscopy in frequencies that range from 10 Hz to 1 GHz has been used to study the molecular orientational dynamics of the two types of dimers that form the twist-bend nematic phase over a wide range of temperatures for both nematic and twist-bend nematic phases. The...
Autores principales: | , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
American Chemical Society
2023
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10424235/ https://www.ncbi.nlm.nih.gov/pubmed/37526147 http://dx.doi.org/10.1021/acs.jpcb.3c03496 |
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author | Kocot, Antoni Czarnecka, Małgorzata Arakawa, Yuki Merkel, Katarzyna |
author_facet | Kocot, Antoni Czarnecka, Małgorzata Arakawa, Yuki Merkel, Katarzyna |
author_sort | Kocot, Antoni |
collection | PubMed |
description | [Image: see text] Dielectric spectroscopy in frequencies that range from 10 Hz to 1 GHz has been used to study the molecular orientational dynamics of the two types of dimers that form the twist-bend nematic phase over a wide range of temperatures for both nematic and twist-bend nematic phases. The symmetrical and asymmetrical liquid crystal dimers with the cyanobiphenyl mesogenic groups were investigated. The results were analyzed within the framework of the molecular theory of dielectric permittivity for nematogens. The two molecular processes can be assigned to the reorientation of the monomeric unit: the high frequency one to the precessional rotation of the longitudinal components of the cyanobiphenyl groups (CN) and the second (low frequency) to the end-over-end rotation of the CN dipole around the short molecular axis. The precession mode, which is determined by the local order and is almost unaffected by the phase transition from the nematic to the twist-bend phase, while the end-over-end rotation clearly slowed down at the transition, as it is affected by the growth of the intermolecular interactions. The latter corresponds well to the fact revealed by IR spectroscopy about the longitudinal correlation of the molecular dipoles. |
format | Online Article Text |
id | pubmed-10424235 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2023 |
publisher | American Chemical Society |
record_format | MEDLINE/PubMed |
spelling | pubmed-104242352023-08-15 Dielectric Study of Liquid Crystal Dimers: Probing the Orientational Order and Molecular Interactions in Nematic and Twist-Bend Nematic Phases Kocot, Antoni Czarnecka, Małgorzata Arakawa, Yuki Merkel, Katarzyna J Phys Chem B [Image: see text] Dielectric spectroscopy in frequencies that range from 10 Hz to 1 GHz has been used to study the molecular orientational dynamics of the two types of dimers that form the twist-bend nematic phase over a wide range of temperatures for both nematic and twist-bend nematic phases. The symmetrical and asymmetrical liquid crystal dimers with the cyanobiphenyl mesogenic groups were investigated. The results were analyzed within the framework of the molecular theory of dielectric permittivity for nematogens. The two molecular processes can be assigned to the reorientation of the monomeric unit: the high frequency one to the precessional rotation of the longitudinal components of the cyanobiphenyl groups (CN) and the second (low frequency) to the end-over-end rotation of the CN dipole around the short molecular axis. The precession mode, which is determined by the local order and is almost unaffected by the phase transition from the nematic to the twist-bend phase, while the end-over-end rotation clearly slowed down at the transition, as it is affected by the growth of the intermolecular interactions. The latter corresponds well to the fact revealed by IR spectroscopy about the longitudinal correlation of the molecular dipoles. American Chemical Society 2023-08-01 /pmc/articles/PMC10424235/ /pubmed/37526147 http://dx.doi.org/10.1021/acs.jpcb.3c03496 Text en © 2023 The Authors. Published by American Chemical Society https://creativecommons.org/licenses/by/4.0/Permits the broadest form of re-use including for commercial purposes, provided that author attribution and integrity are maintained (https://creativecommons.org/licenses/by/4.0/). |
spellingShingle | Kocot, Antoni Czarnecka, Małgorzata Arakawa, Yuki Merkel, Katarzyna Dielectric Study of Liquid Crystal Dimers: Probing the Orientational Order and Molecular Interactions in Nematic and Twist-Bend Nematic Phases |
title | Dielectric Study
of Liquid Crystal Dimers: Probing
the Orientational Order and Molecular Interactions in Nematic and
Twist-Bend Nematic Phases |
title_full | Dielectric Study
of Liquid Crystal Dimers: Probing
the Orientational Order and Molecular Interactions in Nematic and
Twist-Bend Nematic Phases |
title_fullStr | Dielectric Study
of Liquid Crystal Dimers: Probing
the Orientational Order and Molecular Interactions in Nematic and
Twist-Bend Nematic Phases |
title_full_unstemmed | Dielectric Study
of Liquid Crystal Dimers: Probing
the Orientational Order and Molecular Interactions in Nematic and
Twist-Bend Nematic Phases |
title_short | Dielectric Study
of Liquid Crystal Dimers: Probing
the Orientational Order and Molecular Interactions in Nematic and
Twist-Bend Nematic Phases |
title_sort | dielectric study
of liquid crystal dimers: probing
the orientational order and molecular interactions in nematic and
twist-bend nematic phases |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10424235/ https://www.ncbi.nlm.nih.gov/pubmed/37526147 http://dx.doi.org/10.1021/acs.jpcb.3c03496 |
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