Polyimide photo-alignment layers for inclined homeotropic alignment of liquid crystal molecules

Kiyoaki Usami, Kenji Sakamoto, Junichiro Yokota, Yoichi Uehara, Sukekatsu Ushioda

Research output: Contribution to journalArticlepeer-review

15 Citations (Scopus)

Abstract

We have succeeded in realizing an inclined homeotropic alignment of liquid crystal (LC) molecules by using photo-aligned films of a polyimide containing azobenzene in the backbone structure. To induce such an LC alignment, a side chain structure was introduced into the backbone structure. The LC pretilt angle, measured from the surface normal, could be controlled up to 1.75° by varying the light exposure in oblique angle irradiation with unpolarized light. Its thermal stability was examined by annealing the LC cell at 100 °C. No change was observed in the pretilt angle even after annealing for 36 h, indicative of its excellent thermal stability. Since photo-alignment has patterning capability, the photo-aligned polyimide film is expected as a promising alignment film for multi-domain vertical alignment mode LC displays.

Original languageEnglish
Pages (from-to)2652-2655
Number of pages4
JournalThin Solid Films
Volume516
Issue number9
DOIs
Publication statusPublished - 2008 Mar 3
Externally publishedYes

Keywords

  • Inclined homeotropic alignment of liquid crystal molecules
  • Photo-induced alignment method
  • Polyimide containing azobenzene in the backbone structure
  • Pretilt angle

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Metals and Alloys
  • Materials Chemistry

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