Novel Liquid Crystalline Structure in Langmuir Monolayers of Amphiphilic Azobenzene Derivative

Yuka Tabe, Hiroshi Yokoyama

Research output: Contribution to journalArticlepeer-review

28 Citations (Scopus)


Depolarized Brewster-angle microscopy revealed a novel two-dimensional (2D) mesophase in Langmuir monolayers of 4-octyl-4'-(3-carboxytrimethyleneoxy) azobenzene, characterized by ubiquitous schlieren textures resulting from the long-range order of in-plane molecular orientations. The lack of half-integral strength disclinations and the presence of a regular array of π-walls, across which the in-plane orientation changes by 180 degrees, indicate the vectorial nature of the underlying order parameter. The monolayer can, therefore, be viewed as a single layer of a bulk smectic C phase or as a 2D polar nematic phase, except for the obvious absence of mirror symmetry with respect to the layer plane. In contrast to the experience with bulk liquid crystalline phases, higher-order point disclinations were often found stable in the monolayer.

Original languageEnglish
Pages (from-to)2472-2476
Number of pages5
Journaljournal of the physical society of japan
Issue number7
Publication statusPublished - 1994 Jan 1
Externally publishedYes


  • 2D liquid crystal
  • Brewster-angle microscopy
  • Langmuir monolayer
  • modulated phase
  • point disclination
  • schlieren texture
  • π-wall

ASJC Scopus subject areas

  • General Physics and Astronomy


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