Molecular ordering of the discotic liquid crystal HAT6 confined in mesoporous solids

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Autor/in:
Verlag/Körperschaft:
Hamburg University of Technology
Erscheinungsjahr:
2014
Medientyp:
Text
Schlagworte:
  • Columnar discotics
  • Nanocomposites
  • Porous alumina
  • Porous silica
  • Porous silicon
  • 530: Physik
  • 600: Technik
Beschreibung:
  • An optical polarimetry study of the orientational order of a discotic liquid crystal (DLC), 2,3,6,7,10,11-hexakis(hexyloxy)triphenylene (HAT6), confined into parallel-aligned cylindrical nanochannels of mesoporous alumina, silica, and silicon membranes as a function of temperature and channel radius (3.4-21.0 nm) is presented. In contrast to the bulk state, the birefringence resulting from the confined discotic liquid crystal, exhibits a continuous temperature evolution and is positive indicating a dominating face-on (homeotropic) type molecular ordering with respect to the channel walls. Pronounced hysteresis effects observed in the experiment are traced to different nucleation sites of the low-temperature phase upon cooling and the high-temperature phase upon heating. Deviations from the Gibbs-Thomson scaling of the phase transition temperature for channel diameters below 10 nm are traced to splay distortions of the confined liquid crystal. © 2014 Elsevier Inc. All rights reserved.
Beziehungen:
DOI 10.1016/j.micromeso.2014.05.036
Quellsystem:
TUHH Open Research
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oai:tore.tuhh.de:11420/12791