Publicación:
Energetics and structures of the tilted phases of fatty acid Langmuir monolayers

Vista sencilla de ítem
dc.contributor.authorToledano Sanz, Óscar
dc.contributor.authorRubio Álvarez, Miguel Ángel
dc.contributor.authorGálvez González, Óscar
dc.date.accessioned2024-05-20T11:28:19Z
dc.date.available2024-05-20T11:28:19Z
dc.date.issued2020
dc.description.abstractLangmuir monolayers are monomolecular deep films composed of amphiphilic molecules which are typically confined to a water/air interface in a bi-dimensional structure. Due to the important applications in many research areas, they have been studied for many years. Their phase diagrams present several condensed phases, showing untilted or tilted structures at low values of surface pressure. In this paper, we present a novel density functional study on tilted phases of different fatty acid Langmuir monolayers. By means of this study, a further understanding of the physical chemistry properties and the nature of the formation of tilted monolayers can be achieved. Our calculations reveal that, regardless of the number of carbon atoms which form the apolar chain, the transversal (or conventional in the case of untilted phases) unit cell shows similar dimensions, ca. 4.9 × 6.8 Å, which is in fair agreement with the range of the observed data. The energy variation of the unit cell as a function of the inclination of the molecules, reveals an abrupt increase in values larger than 45° and 36° for NN- and NNN-tilt, respectively, in fair agreement with the experimental observation of L2h (NN) and L2′ (NNN) phases of fatty acids. All of the fatty acids explored (from 10 to 19 carbon atoms) yield similar results. Finally, the energetics and structural changes of the monolayer along the variation of the area per molecule, obtained by enlarging in a-, b- or both axes of the untilted unit cell, have been explored. This study reveals that the untilted phases are energetically more stable at low values of area per molecule (high surface concentration), as it is expected. When the area per molecule values are increased, tilted phases (along NN or NNN-direction) with b/a ratio typical of herringbone (HB) or pseudo-herringbone (PHB) structures are found in the lowest energy configurations, which depend on how the distortion of the untilted unit cell is performed. For example, HB structures are the most stable when the molecules tilt along the enlarged axis of the untilted unit cell (a or b), meanwhile unit cell structures characteristic of PHB configurations occur in the opposite cases and at larger values of the area per molecule (low surface concentrations). All these predictions are in good agreement with the GIXD observations of the different phases of the phase diagram of fatty acid Langmuir monolayers.en
dc.description.versionversión final
dc.identifier.doihttp://doi.org/10.1039/D0CP01361G
dc.identifier.issn1463-9084
dc.identifier.urihttps://hdl.handle.net/20.500.14468/12058
dc.journal.titlePhysical Chemistry Chemical Physics
dc.journal.volume22
dc.language.isoen
dc.publisherRoyal Society of Chemistry
dc.relation.centerFacultad de Ciencias
dc.relation.departmentFísica Fundamental
dc.rightsinfo:eu-repo/semantics/openAccess
dc.rights.urihttps://creativecommons.org/licenses/by-nc-nd/4.0/deed.es
dc.subject.keywordsLangmuir monolayer
dc.subject.keywordsfatty acids
dc.subject.keywordsdihydrogen interactions
dc.subject.keywordstilted phases
dc.subject.keywordsDFT calculations
dc.titleEnergetics and structures of the tilted phases of fatty acid Langmuir monolayerses
dc.typejournal articleen
dc.typeartículoes
dspace.entity.typePublication
relation.isAuthorOfPublication72b031b9-d091-4c35-b48f-b97c34b9d539
relation.isAuthorOfPublication283ce738-b7b4-4df7-a7d7-4903d7d0eba6
relation.isAuthorOfPublication8c553812-bd9e-4899-87cc-ad40e9bd8338
relation.isAuthorOfPublication.latestForDiscovery72b031b9-d091-4c35-b48f-b97c34b9d539
Archivos
Bloque original
Mostrando 1 - 1 de 1
Miniatura
Nombre:
Rubio_Alvarez_Miguel_Angel_Energetics.pdf
Tamaño:
1.73 MB
Formato:
Adobe Portable Document Format
Descargar
Colecciones
Artículos y papers