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Photo-Orientation of Liquid Crystals Due To Light-Induced Desorption and Adsorption of Dye Molecules on an Aligning Surface
Physical Review E
  • E. Ouskova, Institute of Physics, Ukraine
  • Yurii Reznikov, Institute of Physics, Ukraine
  • S. V Shiyanovskii, Kent State University - Kent Campus
  • L. Su, Kent State University - Kent Campus
  • John L West, Kent State University
  • O. V Kuksenok, Institute for Nuclear Research, Ukraine
  • O. Francescangeli, Universita di Ancona
  • F. Simoni, Universita di Ancona
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We show that adsorption of dye molecules control the light-induced alignment of dye-doped nematic liquid crystal (LC) on a nonphotosensitive polymer surface. The dependencies of light-induced twist structures on exposure, thermal baking, thickness, and aging before irradiation of the LC cells allowed us to propose the following mechanism for the alignment. Before irradiation, the “dark”-adsorbed layer on the tested surface is formed from dye molecules predominantly aligned along the initial direction of the director. Irradiation of the cell with linearly polarized light produces an additional layer with different orientational ordering of dye molecules. The final easy axis is determined by the competition of “dark” and light-induced contributions to anchoring and is aligned between the “dark” easy axes and polarization of the light. For quantitative interpretation, we apply the tensor model of anchoring and assume that the photoalignment in the mesophase is a cumulative effect of the light-induced anchoring on the background of the already existing anisotropic “dark” dye layer.

Copyright 2001 American Physical Society. Available on publisher's site at

Citation Information
E. Ouskova, Yurii Reznikov, S. V Shiyanovskii, L. Su, et al.. "Photo-Orientation of Liquid Crystals Due To Light-Induced Desorption and Adsorption of Dye Molecules on an Aligning Surface" Physical Review E Vol. 64 Iss. 5 (2001)
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