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dc.contributor.authorLópez Pérez, David Orencio
dc.contributor.authorRobles Hernández, Beatriz
dc.contributor.authorSalud Puig, Josep
dc.contributor.authorDe la Fuente, Maria Rosario
dc.contributor.authorSebastian, N.
dc.contributor.authorDíez Berart, Sergio
dc.contributor.authorJaen, X.
dc.contributor.authorDunmur, D.A.
dc.contributor.authorLuckhurst, G.R.
dc.contributor.otherUniversitat Politècnica de Catalunya. Departament de Física
dc.date.accessioned2016-04-18T09:16:42Z
dc.date.available2017-01-14T01:30:17Z
dc.date.issued2016-01-14
dc.identifier.citationLopez, D., Robles-Hernández, B., Salud, J., De la Fuente, M., Sebastian, N., Diez, S., Jaen, X., Dunmur, D., Luckhurst , G. Miscibility studies of two twist-bend nematic liquid crystal dimers with different average molecular curvatures. A comparison between experimental data and predictions of a Landau mean-field theory for the NTB-N phase transition. "Physical chemistry chemical physics", 14 Gener 2016, vol. 18, p. 4394-4404.
dc.identifier.issn1463-9076
dc.identifier.urihttp://hdl.handle.net/2117/85770
dc.description.abstractWe report a calorimetric study of a series of mixtures of two twist-bend liquid crystal dimers, the 1'',7''-bis(4-cyanobiphenyl)-4'-yl heptane (CB7CB) and 1''-(2',4-difluorobiphenyl-4'-yloxy)-9''-(4-cyanobiphenyl-4'-yloxy) nonane (FFO9OCB), the molecules of which have different effective molecular curvatures. High-resolution heat capacity measurements in the vicinity of the NTB-N phase transition for a selected number of binary mixtures clearly indicate a first order NTB-N phase transition for all the investigated mixtures, the strength of which decreases when the nematic range increases. Published theories predict a second order NTB-N phase transition, but we have developed a self-consistent mean field Landau model using two key order parameters: A symmetric and traceless tensor for the orientational order and a short-range vector field which is orthogonal to the helix axis and rotates around of the heliconical structure with an extremely short periodicity. The theory, in its simplified form, depends on two effective elastic constants and explains satisfactorily our heat capacity measurements and also predicts a first-order NTB-N phase transition. In addition, as a complementary source of experimental measurements, the splay (K1) and bend (K3) elastic constants in the conventional nematic phase for the pure compounds and some selected mixtures have been determined.
dc.format.extent11 p.
dc.language.isoeng
dc.rights.urihttp://creativecommons.org/licenses/by-nc-nd/3.0/es/
dc.subjectÀrees temàtiques de la UPC::Enginyeria química::Química física
dc.subject.lcshChemistry, Physical and theorica
dc.subject.lcshCalorimetry
dc.titleMiscibility studies of two twist-bend nematic liquid crystal dimers with different average molecular curvatures. A comparison between experimental data and predictions of a Landau mean-field theory for the NTB-N phase transition
dc.typeArticle
dc.subject.lemacFisicoquímica
dc.subject.lemacCalorimetria
dc.identifier.doi10.1039/c5cp07605f
dc.rights.accessOpen Access
drac.iddocument17680097
dc.description.versionPostprint (author's final draft)
upcommons.citation.authorLopez, D., Robles-Hernández, B., Salud, J., De la Fuente, M., Sebastian, N., Diez, S., Jaen, X., Dunmur, D., Luckhurst , G.
upcommons.citation.publishedtrue
upcommons.citation.publicationNamePhysical chemistry chemical physics
upcommons.citation.volume18
upcommons.citation.startingPage4394
upcommons.citation.endingPage4404


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