Liquid crystal beads constrained on thin cellulosic fibers: Electric field induced microrotors and N-I transition

Detalhes bibliográficos
Autor(a) principal: Geng, Yong
Data de Publicação: 2012
Outros Autores: Almeida, Pedro L., Figueirinhas, João, Terentjev, Eugene, Godinho, Maria Helena
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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spelling 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
rights_invalid_str_mv 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
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instname_str Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação
instacron_str RCAAP
institution RCAAP
reponame_str Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
collection Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
repository.name.fl_str_mv Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação
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