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Two negative minima of the first normal stress difference in a cellulose-based cholesteric liquid crystal: Helix uncoiling

2017-05-15Journal article Open access
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dc.contributor.authorEcheverria Zabala, Coro
dc.contributor.authorAlmeida, Pedro L.
dc.contributor.authorGutierrez, Oscar F. Aguilar
dc.contributor.authorRey, Alejandro D.
dc.contributor.authorGodinho, Maria Helena
dc.date.accessioned2017-03-28T07:58:29Z
dc.date.available2017-03-28T07:58:29Z
dc.date.issued2017-05-15
dc.description.abstractThe shear rate dependence of material functions such as shear viscosity (η) and the first normal stress difference (N1) were given and interpreted earlier by Kiss and Porter. Their widely accepted work revealed the possibility of having a negative minimum of N1 for polymeric liquid crystals. In this work, we disclose for the first time the evidence of two negative N1 minima on a sheared cellulosic lyotropic system. The lower shear rate minimum is ascribed to the uncoiling of the cholesteric helix, as theoretically predicted earlier. Our findings contribute also to the understanding of the other minimum already reported in the literature and attributed to the nematic director tumbling mode. Moreover, the elastic change that the LC-HPC sample undergoes during the helix unwinding of the cholesteric structure is also by means of oscillatory measurements. This study is a contribution for the understanding of the structure-properties relationship linked with the complex rheological behavior of chiral nematic cellulose-based systems and may help to improve their further processing. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys.pt_PT
dc.description.versioninfo:eu-repo/semantics/publishedVersionpt_PT
dc.identifier.citationECHEVERRIA, Coro; [et al] – Two negative minima of the first normal stress difference in a cellulose-based cholesteric liquid crystal: Helix uncoiling. Journal of Polimer Science Part B - Polymer Phisics. ISSN 0887-6266. Vol. 55, N.º 10 (2017), pp. 821-830pt_PT
dc.identifier.doi10.1002/polb.24332pt_PT
dc.identifier.issn0887-6266
dc.identifier.urihttp://hdl.handle.net/10400.21/6887
dc.language.isoengpt_PT
dc.peerreviewedyespt_PT
dc.publisherJournal of Polymer Science, Part Bpt_PT
dc.relation.publisherversionhttp://onlinelibrary.wiley.com/doi/10.1002/polb.24332/epdfpt_PT
dc.subjectBiopolymerspt_PT
dc.subjectcellulose derivativept_PT
dc.subjecthelix uncoilingpt_PT
dc.subjectliquid-crystalline polymers (LCP)pt_PT
dc.subjectpolymeric liquid crystalpt_PT
dc.subjectrheologypt_PT
dc.titleTwo negative minima of the first normal stress difference in a cellulose-based cholesteric liquid crystal: Helix uncoilingpt_PT
dc.typejournal article
dspace.entity.typePublication
oaire.citation.endPage830pt_PT
oaire.citation.issue10
oaire.citation.startPage821pt_PT
oaire.citation.titleJournal of Polymer Science Part B - Polymer Physicspt_PT
oaire.citation.volume55
person.familyNameEcheverria Zabala
person.familyNameMarques de Almeida
person.familyNameGodinho
person.givenNameCoro
person.givenNamePedro
person.givenNameMaria Helena
person.identifier.ciencia-id0218-71B2-2DE0
person.identifier.ciencia-idC316-7B1F-4513
person.identifier.orcid0000-0002-0734-766X
person.identifier.orcid0000-0001-7356-8455
person.identifier.orcid0000-0002-9760-5983
person.identifier.ridJ-5207-2013
person.identifier.ridB-4356-2009
person.identifier.ridJ-3679-2013
person.identifier.scopus-author-id35233119700
person.identifier.scopus-author-id57190384213
person.identifier.scopus-author-id7005654016
rcaap.rightsrestrictedAccesspt_PT
rcaap.typearticlept_PT
relation.isAuthorOfPublication1aea19e7-2c7f-4c91-85a3-e6b40c2d75dd
relation.isAuthorOfPublication429b6d71-328e-42b3-8151-15493de249b8
relation.isAuthorOfPublication9e92c2e7-f179-42a4-b284-2b30b769aa0b
relation.isAuthorOfPublication.latestForDiscovery9e92c2e7-f179-42a4-b284-2b30b769aa0b

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