Transactions on Electrical and Electronic Materials

The Korean Institute of Electrical and Electronic Material Engineers (한국전기전자재료학회)
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Washing Effects on Generation of Pretilt Angle in NLC, 5CB, on a Polyimide Surface with Trifluoromethyl Moieties

  • Lee, Sang-Keuk (Department of Electrical Engineering, College of Engineering, Kwangwoon University) ;
  • Han, Jeong-Min (Department of Electrical and Electronic Engineering(A-226), College of Engineering) ;
  • Hwang, Jeoung-Yeon (Department of Electrical and Electronic Engineering(A-226), College of Engineering) ;
  • Seo, Dae-Shik (Department of Electrical and Electronic Engineering(A-226), College of Engineering)
  • Published : 2003.02.01
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Abstract

The washing effects on pretilt angle generation in a nematic liquid crystal (NLC), 4-n-pentyl-4'-cyanobiphenyl (5CB) on a rubbed polyimide (PI) surface with trifluoromethyl moiety have been successfully studied. The pretilt angle of 5CB is increased by the washing process on the rubbed PI surface. The surface tension on the rubbed PI surface increases with the rubbing strength RS and then saturated above RS: 150 mm. The pretilt angle of 5CB for all washing processes on the rubbed PI surface decreases with the surface tension. We have found that the pretilt angle of 5CB on the rubbed PI surface may be attributed van der walls (VDW) dispersion interaction between the LC molecules and the polymer surfaces having trifluoromethyl moieties.

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References

  1. T. Miyashita, Y. Yamaguchi, and T. Uchida, 'Wide viewing-angle display mode using bendalignment liquid crystal Cell', Jpn. J. Appl. Phys., Vol. 34. No. 2A, p. L177. 1995 https://doi.org/10.1143/JJAP.34.177
  2. T. Sugiyama, S. Kuniyasu, D.S. Seo, H. Fukuro, and S. Kobayashi, 'A simple model for pretilted nematic liquid crystal medium and its torsional surface coupling strength', Jpn. J. Appl. Phys., Vol. 29, No. 10, p. 2045, 1990 https://doi.org/10.1143/JJAP.29.2045
  3. D.-S. Seo, K. Muroi. and S. Kobayashi, ' Generation of pretilt angles in nematic liquid crystal, 5CB, media aligned polyimide films', Mol. Cryst. Liq. Cryst., Vol. 213, p. 223,1992 https://doi.org/10.1080/10587259208028733
  4. D.S. Seo, K. Araya, N. Yoshida, M. Nishikawa, Y. Yabe, and S. Kobatashi, 'Effect of the polymer tilt angle for generation of pretilt angle in nematic liquid crystal on rubbed polyimide Surfaces', Jpn. J. Appl. Phys., Vol.34. No. 4B, p. L503, 1995 https://doi.org/10.1143/JJAP.34.L503
  5. J.Y. Hwang, D.S. Seo, E.J. Hahn, and J.H. Kim, 'Liquid crystal alignment effects for the photoaligned VA LCD on the photo polymer', Trans. on EEM,Vol. 1, No. 3, p. 10, 2000
  6. Y.M. Jo, J.Y. Hwang, D.S. Seo, and S.K. Lee, 'Alignment effects for nematic liquid crystal on a new diamond like carbon layer', Trans. on EEM, Vol. 3, No. 2, p. 1, 2002
  7. S.K. Lee, J.U. Lee, J.M. Han, J.Y. Hwang, D.S. Seo, and S.K. Paek, 'Polar anchoring strength and surface ordering in NLC by the washing process on rubbed polymer surfaces containing trifluoromethyl moiety', Trans. on EEM, Vol. 3, No. 4, p.36, 2002
  8. D.S. Seo, S. Kobayashi, and M. Nishikawa, 'Study of the pretilt angle for 5CB on rubbed polyimide films containing tnfluoromethyl moiety and analysis of the surface atomic concentration of F/C(%) with an electron spectroscope for chemical analysis', Appl. Phys. Lett., Vol. 61, No. 20, p. 2392. 1992 https://doi.org/10.1063/1.108174
  9. H. Matsuda, D.S. Seo, N. Yoshida, K. Fujibayashi, S. Kobayashi, and Y. Yabe, 'Estimation of the static electricity and optical retardation produced by the rubbing polyimide and polyamide films with different fabrics', Mol. Cryst. Liq. Cryst., Vol. 264, p. 23, 1995 https://doi.org/10.1080/10587259508037298