Rheo-NMR study of water-based cellulose liquid crystal system at high shear rates

Detalhes bibliográficos
Autor(a) principal: Echeverria, Coro
Data de Publicação: 2015
Outros Autores: Almeida, Pedro L., Feio, Gabriel, Figueirinhas, João, Rey, Alejandro D., 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/10400.21/5916
Resumo: Since long ago cellulosic lyotropic liquid crystals were thought as potential materials to produce fibers competitive with spidersilk or Kevlar, yet the processing of high modulus materials from cellulose-based precursors was hampered by their complex rheological behavior. In this work, by using the Rheo-NMR technique, which combines deuterium NMR with rheology, we investigate the high shear rate regimes that may be of interest to the industrial processing of these materials. Whereas the low shear rate regimes were already investigated by this technique in different works [1-4], the high shear rates range is still lacking a detailed study. This work focuses on the orientational order in the system both under shear and subsequent relaxation process arising after shear cessation through the analysis of deuterium spectra from the deuterated solvent water. At the analyzed shear rates the cholesteric order is suppressed and a flow-aligned nematic is observed which for the higher shear rates develops after certain time periodic perturbations that transiently annihilate the order in the system. During relaxation the flow aligned nematic starts losing order due to the onset of the cholesteric helices leading to a period of very low order where cholesteric helices with different orientations are forming from the aligned nematic, followed in the final stage by an increase in order at long relaxation times corresponding to the development of aligned cholesteric domains. This study sheds light on the complex rheological behavior of chiral nematic cellulose-based systems and opens ways to improve its processing. (C) 2015 Elsevier Ltd. All rights reserved.
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spelling Rheo-NMR study of water-based cellulose liquid crystal system at high shear ratesCelluloseLiquid crystalRheo-NMRSince long ago cellulosic lyotropic liquid crystals were thought as potential materials to produce fibers competitive with spidersilk or Kevlar, yet the processing of high modulus materials from cellulose-based precursors was hampered by their complex rheological behavior. In this work, by using the Rheo-NMR technique, which combines deuterium NMR with rheology, we investigate the high shear rate regimes that may be of interest to the industrial processing of these materials. Whereas the low shear rate regimes were already investigated by this technique in different works [1-4], the high shear rates range is still lacking a detailed study. This work focuses on the orientational order in the system both under shear and subsequent relaxation process arising after shear cessation through the analysis of deuterium spectra from the deuterated solvent water. At the analyzed shear rates the cholesteric order is suppressed and a flow-aligned nematic is observed which for the higher shear rates develops after certain time periodic perturbations that transiently annihilate the order in the system. During relaxation the flow aligned nematic starts losing order due to the onset of the cholesteric helices leading to a period of very low order where cholesteric helices with different orientations are forming from the aligned nematic, followed in the final stage by an increase in order at long relaxation times corresponding to the development of aligned cholesteric domains. This study sheds light on the complex rheological behavior of chiral nematic cellulose-based systems and opens ways to improve its processing. (C) 2015 Elsevier Ltd. All rights reserved.Elsevier SCI LTDRCIPLEcheverria, CoroAlmeida, Pedro L.Feio, GabrielFigueirinhas, JoãoRey, Alejandro D.Godinho, Maria Helena2016-03-18T15:11:56Z2015-05-182015-05-18T00:00:00Zinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articleapplication/pdfhttp://hdl.handle.net/10400.21/5916engECHEVERRIA, Coro; [et al.] - Rheo-NMR study of water-based cellulose liquid crystal system at high shear rates. Polymer. ISSN. 0032-3861. Vol. 65 (2015), pp. 18-250032-386110.1016/j.polymer.2015.03.050metadata 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:RCAAP2023-08-03T09:50:01Zoai:repositorio.ipl.pt:10400.21/5916Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireopendoar:71602024-03-19T20:15:07.943459Repositório 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 Rheo-NMR study of water-based cellulose liquid crystal system at high shear rates
title Rheo-NMR study of water-based cellulose liquid crystal system at high shear rates
spellingShingle Rheo-NMR study of water-based cellulose liquid crystal system at high shear rates
Echeverria, Coro
Cellulose
Liquid crystal
Rheo-NMR
title_short Rheo-NMR study of water-based cellulose liquid crystal system at high shear rates
title_full Rheo-NMR study of water-based cellulose liquid crystal system at high shear rates
title_fullStr Rheo-NMR study of water-based cellulose liquid crystal system at high shear rates
title_full_unstemmed Rheo-NMR study of water-based cellulose liquid crystal system at high shear rates
title_sort Rheo-NMR study of water-based cellulose liquid crystal system at high shear rates
author Echeverria, Coro
author_facet Echeverria, Coro
Almeida, Pedro L.
Feio, Gabriel
Figueirinhas, João
Rey, Alejandro D.
Godinho, Maria Helena
author_role author
author2 Almeida, Pedro L.
Feio, Gabriel
Figueirinhas, João
Rey, Alejandro D.
Godinho, Maria Helena
author2_role author
author
author
author
author
dc.contributor.none.fl_str_mv RCIPL
dc.contributor.author.fl_str_mv Echeverria, Coro
Almeida, Pedro L.
Feio, Gabriel
Figueirinhas, João
Rey, Alejandro D.
Godinho, Maria Helena
dc.subject.por.fl_str_mv Cellulose
Liquid crystal
Rheo-NMR
topic Cellulose
Liquid crystal
Rheo-NMR
description Since long ago cellulosic lyotropic liquid crystals were thought as potential materials to produce fibers competitive with spidersilk or Kevlar, yet the processing of high modulus materials from cellulose-based precursors was hampered by their complex rheological behavior. In this work, by using the Rheo-NMR technique, which combines deuterium NMR with rheology, we investigate the high shear rate regimes that may be of interest to the industrial processing of these materials. Whereas the low shear rate regimes were already investigated by this technique in different works [1-4], the high shear rates range is still lacking a detailed study. This work focuses on the orientational order in the system both under shear and subsequent relaxation process arising after shear cessation through the analysis of deuterium spectra from the deuterated solvent water. At the analyzed shear rates the cholesteric order is suppressed and a flow-aligned nematic is observed which for the higher shear rates develops after certain time periodic perturbations that transiently annihilate the order in the system. During relaxation the flow aligned nematic starts losing order due to the onset of the cholesteric helices leading to a period of very low order where cholesteric helices with different orientations are forming from the aligned nematic, followed in the final stage by an increase in order at long relaxation times corresponding to the development of aligned cholesteric domains. This study sheds light on the complex rheological behavior of chiral nematic cellulose-based systems and opens ways to improve its processing. (C) 2015 Elsevier Ltd. All rights reserved.
publishDate 2015
dc.date.none.fl_str_mv 2015-05-18
2015-05-18T00:00:00Z
2016-03-18T15:11:56Z
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/10400.21/5916
url http://hdl.handle.net/10400.21/5916
dc.language.iso.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv ECHEVERRIA, Coro; [et al.] - Rheo-NMR study of water-based cellulose liquid crystal system at high shear rates. Polymer. ISSN. 0032-3861. Vol. 65 (2015), pp. 18-25
0032-3861
10.1016/j.polymer.2015.03.050
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
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dc.publisher.none.fl_str_mv Elsevier SCI LTD
publisher.none.fl_str_mv Elsevier SCI LTD
dc.source.none.fl_str_mv reponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
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