Vertical alignment of liquid crystals with negative dielectric anisotropy on an inorganic thin film with a hydrophilic surface

Har Hwang Byoung, Jin Ahn Han, Joon Rho Soon, Sang Chae Soo, Koo Baik Hong

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

The vertical alignment of liquid crystals having negative dielectric anisotropy on an amorphous silicon Oxide (a-SiOx) thin film is the consequence of the anisotropic interaction between liquid crystals and a-SiOx thin films. To investigate the mechanism of the vertical alignment, we changed the physicochemical characteristics of alignment layers by controlling the composition, since the anisotropic interaction depends on the nature of both liquid crystals and an alignment layer. The variation of composition gives rise to a change in the polarizability, which is a simple measure of induced-dipole strength at the surface of the alignment layer. There is a critical transition point from planar to vertical alignment of liquid crystals, and it is the long-range van der Waals interaction that is responsible for the vertical alignment. The competition between long-range van der Waals interaction and short-range dipolar interaction were investigated and analyzed in terms of the interfacial energy between liquid rystals and an alignment layer.

Original languageEnglish
Pages (from-to)8306-8312
Number of pages7
JournalLangmuir
Volume25
Issue number14
DOIs
Publication statusPublished - 2009 Jul 21

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Spectroscopy
  • Electrochemistry

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