Liquid crystal beads constrained on thin cellulosic fibers: Electric field induced microrotors and N-I transition
Autor(a) principal: | |
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Data de Publicação: | 2012 |
Outros Autores: | , , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
Texto Completo: | http://hdl.handle.net/10400.21/5154 |
Resumo: | We directly visualize the response of nematic liquid crystal drops of toroidal topology threaded in cellulosic fibers, suspended in air, to an AC electric field and at different temperatures over the N-I transition. This new liquid crystal system can exhibit non-trivial point defects, which can be energetically unstable against expanding into ring defects depending on the fiber constraining geometries. The director anchoring tangentially near the fiber surface and homeotropically at the air interface makes a hybrid shell distribution that in turn causes a ring disclination line around the main axis of the fiber at the center of the droplet. Upon application of an electric field, E, the disclination ring first expands and moves along the fiber main axis, followed by the appearance of a stable "spherical particle" object orbiting around the fiber at the center of the liquid crystal drop. The rotation speed of this particle was found to vary linearly with the applied voltage. This constrained liquid crystal geometry seems to meet the essential requirements in which soliton-like deformations can develop and exhibit stable orbiting in three dimensions upon application of an external electric field. On changing the temperature the system remains stable and allows the study of the defect evolution near the nematic-isotropic transition, showing qualitatively different behaviour on cooling and heating processes. The necklaces of such liquid crystal drops constitute excellent systems for the study of topological defects and their evolution and open new perspectives for application in microelectronics and photonics. |
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Liquid crystal beads constrained on thin cellulosic fibers: Electric field induced microrotors and N-I transitionStructural TransformationsAlignment LayersLight-ScatteringPoint-DefectsNematic DropsFilmsMicrodropletsElasticityWe directly visualize the response of nematic liquid crystal drops of toroidal topology threaded in cellulosic fibers, suspended in air, to an AC electric field and at different temperatures over the N-I transition. This new liquid crystal system can exhibit non-trivial point defects, which can be energetically unstable against expanding into ring defects depending on the fiber constraining geometries. The director anchoring tangentially near the fiber surface and homeotropically at the air interface makes a hybrid shell distribution that in turn causes a ring disclination line around the main axis of the fiber at the center of the droplet. Upon application of an electric field, E, the disclination ring first expands and moves along the fiber main axis, followed by the appearance of a stable "spherical particle" object orbiting around the fiber at the center of the liquid crystal drop. The rotation speed of this particle was found to vary linearly with the applied voltage. This constrained liquid crystal geometry seems to meet the essential requirements in which soliton-like deformations can develop and exhibit stable orbiting in three dimensions upon application of an external electric field. On changing the temperature the system remains stable and allows the study of the defect evolution near the nematic-isotropic transition, showing qualitatively different behaviour on cooling and heating processes. The necklaces of such liquid crystal drops constitute excellent systems for the study of topological defects and their evolution and open new perspectives for application in microelectronics and photonics.Royal Soc ChemistryRCIPLGeng, YongAlmeida, Pedro L.Figueirinhas, JoãoTerentjev, EugeneGodinho, Maria Helena2015-09-10T11:52:46Z20122012-01-01T00:00:00Zinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articleapplication/pdfapplication/pdfhttp://hdl.handle.net/10400.21/5154engGENG, Yong; [et al] – Liquid crystal beads constrained on thin cellulosic fibers: Electric field induced microrotors and N-I transition. Soft Matter. ISSN: 1744-683X. Vol. 8, nr. 13 (2012), pp. 3634-36401744-683X10.1039/c2sm06602emetadata only accessinfo:eu-repo/semantics/openAccessreponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãoinstacron:RCAAP2023-08-03T09:48:09Zoai:repositorio.ipl.pt:10400.21/5154Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireopendoar:71602024-03-19T20:14:28.387270Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãofalse |
dc.title.none.fl_str_mv |
Liquid crystal beads constrained on thin cellulosic fibers: Electric field induced microrotors and N-I transition |
title |
Liquid crystal beads constrained on thin cellulosic fibers: Electric field induced microrotors and N-I transition |
spellingShingle |
Liquid crystal beads constrained on thin cellulosic fibers: Electric field induced microrotors and N-I transition Geng, Yong Structural Transformations Alignment Layers Light-Scattering Point-Defects Nematic Drops Films Microdroplets Elasticity |
title_short |
Liquid crystal beads constrained on thin cellulosic fibers: Electric field induced microrotors and N-I transition |
title_full |
Liquid crystal beads constrained on thin cellulosic fibers: Electric field induced microrotors and N-I transition |
title_fullStr |
Liquid crystal beads constrained on thin cellulosic fibers: Electric field induced microrotors and N-I transition |
title_full_unstemmed |
Liquid crystal beads constrained on thin cellulosic fibers: Electric field induced microrotors and N-I transition |
title_sort |
Liquid crystal beads constrained on thin cellulosic fibers: Electric field induced microrotors and N-I transition |
author |
Geng, Yong |
author_facet |
Geng, Yong Almeida, Pedro L. Figueirinhas, João Terentjev, Eugene Godinho, Maria Helena |
author_role |
author |
author2 |
Almeida, Pedro L. Figueirinhas, João Terentjev, Eugene Godinho, Maria Helena |
author2_role |
author author author author |
dc.contributor.none.fl_str_mv |
RCIPL |
dc.contributor.author.fl_str_mv |
Geng, Yong Almeida, Pedro L. Figueirinhas, João Terentjev, Eugene Godinho, Maria Helena |
dc.subject.por.fl_str_mv |
Structural Transformations Alignment Layers Light-Scattering Point-Defects Nematic Drops Films Microdroplets Elasticity |
topic |
Structural Transformations Alignment Layers Light-Scattering Point-Defects Nematic Drops Films Microdroplets Elasticity |
description |
We directly visualize the response of nematic liquid crystal drops of toroidal topology threaded in cellulosic fibers, suspended in air, to an AC electric field and at different temperatures over the N-I transition. This new liquid crystal system can exhibit non-trivial point defects, which can be energetically unstable against expanding into ring defects depending on the fiber constraining geometries. The director anchoring tangentially near the fiber surface and homeotropically at the air interface makes a hybrid shell distribution that in turn causes a ring disclination line around the main axis of the fiber at the center of the droplet. Upon application of an electric field, E, the disclination ring first expands and moves along the fiber main axis, followed by the appearance of a stable "spherical particle" object orbiting around the fiber at the center of the liquid crystal drop. The rotation speed of this particle was found to vary linearly with the applied voltage. This constrained liquid crystal geometry seems to meet the essential requirements in which soliton-like deformations can develop and exhibit stable orbiting in three dimensions upon application of an external electric field. On changing the temperature the system remains stable and allows the study of the defect evolution near the nematic-isotropic transition, showing qualitatively different behaviour on cooling and heating processes. The necklaces of such liquid crystal drops constitute excellent systems for the study of topological defects and their evolution and open new perspectives for application in microelectronics and photonics. |
publishDate |
2012 |
dc.date.none.fl_str_mv |
2012 2012-01-01T00:00:00Z 2015-09-10T11:52:46Z |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://hdl.handle.net/10400.21/5154 |
url |
http://hdl.handle.net/10400.21/5154 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
GENG, Yong; [et al] – Liquid crystal beads constrained on thin cellulosic fibers: Electric field induced microrotors and N-I transition. Soft Matter. ISSN: 1744-683X. Vol. 8, nr. 13 (2012), pp. 3634-3640 1744-683X 10.1039/c2sm06602e |
dc.rights.driver.fl_str_mv |
metadata only access info:eu-repo/semantics/openAccess |
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metadata only access |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
application/pdf application/pdf |
dc.publisher.none.fl_str_mv |
Royal Soc Chemistry |
publisher.none.fl_str_mv |
Royal Soc Chemistry |
dc.source.none.fl_str_mv |
reponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação instacron:RCAAP |
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Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
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RCAAP |
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RCAAP |
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Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
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Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
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Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
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