OSA's Digital Library

Optics Express

Optics Express

  • Editor: C. Martijn de Sterke
  • Vol. 17, Iss. 26 — Dec. 21, 2009
  • pp: 23565–23575

Generation of pretilt angles of liquid crystals on cinnamate-based photoalignment layer by a simple directional peel-off process

Jihye Lee, Seungwoo Lee, Yong-Cheol Jeong, Kuk Young Cho, and Jung-Ki Park  »View Author Affiliations

Optics Express, Vol. 17, Issue 26, pp. 23565-23575 (2009)

View Full Text Article

Enhanced HTML    Acrobat PDF (778 KB)

Browse Journals / Lookup Meetings

Browse by Journal and Year


Lookup Conference Papers

Close Browse Journals / Lookup Meetings

Article Tools



As an alternative to the rubbing method, the photoalignment method has been extensively developed for liquid crystal displays owing to its various advantages including the absence of any contamination problems, feasibility of multi-domain structure formation, and low temperature processing capability. However, cinnamate-based photo-reactive materials that are widely used in photoalignment suffer from several limitations including low pretilt angle and limited control of tilted-up direction of the liquid crystals compared to that of the rubbing process. In this work, we demonstrate a simple and convenient method to generate the pretilt angle, compared to that achieved via the rubbing method, by means of a simple directional peel-off process using a photo-reactive cinnamate oligomer having flexible molecular chain.

© 2009 OSA

OCIS Codes
(160.3710) Materials : Liquid crystals
(230.3720) Optical devices : Liquid-crystal devices
(240.6700) Optics at surfaces : Surfaces

ToC Category:
Optical Devices

Original Manuscript: October 1, 2009
Revised Manuscript: November 13, 2009
Manuscript Accepted: November 27, 2009
Published: December 9, 2009

Jihye Lee, Seungwoo Lee, Yong-Cheol Jeong, Kuk Young Cho, and Jung-Ki Park, "Generation of pretilt angles of liquid crystals on cinnamate-based photoalignment layer by a simple directional peel-off process," Opt. Express 17, 23565-23575 (2009)

Sort:  Author  |  Year  |  Journal  |  Reset  


  1. K. Takatoh, M. Hasegawa, M. Koden, N. Itoh, R. Hasegawa, and M. Sakamoto, “Rubbing Technologies: Mechanisms and Applications,” in Alignment Technologies and Applications of Liquid Crystal Devices (Taylor & Francis, 2007), pp.7–8.
  2. W. Gibbons, P. Shannon, S. Sun, and B. Swetlin, “Surface-mediated alignment of nematic liquid crystals with polarized laser light,” Nature 351(6321), 49–50 (1991). [CrossRef]
  3. K. Ichimura, “Photoalignment of liquid-crystal systems,” Chem. Rev. 100(5), 1847–1874 (2000). [CrossRef] [PubMed]
  4. H. Hah, S.-J. Sung, and J.-K. Park, “Ultraviolet embossed alignment layer for flexible liquid crystal display,” Appl. Phys. Lett. 90(6), 063508 (2007). [CrossRef]
  5. J. Janning, “Thin film surface orientation for liquid crystals,” Appl. Phys. Lett. 21(4), 173–174 (1972). [CrossRef]
  6. Y. Kawanishi, T. Tamaki, M. Sakuragi, T. Seki, Y. Suzuki, and K. Ichimura, “Photochemical induction and modulation of nematic homogeneous alignment by the polarization photochromism of surface azobenzenes,” Langmuir 8(11), 2601–2604 (1992). [CrossRef]
  7. K. Ichimura, Y. Suzuki, T. Seki, A. Hosoki, and K. Aoki, ““Reversible change in alignment mode of nematic liquid crystals regulated photochemically by “Command Surface” modified with an azobenzene monolayer,” Langmuir 4(5), 1214–1216 (1988). [CrossRef]
  8. S.-J. Sung, K.-Y. Cho, J.-H. Yoo, W. S. Kim, H.-S. Chang, I. Cho, and J.-K. Park, “Dimerization behavior of cinnamate group attached to flexible polymer backbone and its effect on the molecular orientation,” Chem. Phys. Lett. 394(4-6), 238–243 (2004). [CrossRef]
  9. S.-J. Sung, K.-Y. Cho, and J.-K. Park, “Photo-induced liquid crystal alignment of poly(vinyl cinnamate) and fluorinated polyimide blends,” Mater. Sci. Eng. C 24(1-2), 181–184 (2004). [CrossRef]
  10. S.-J. Sung, K.-Y. Cho, H. Hah, S. Lee, and J.-K. Park, “Effect of plasticization of poly(vinyl cinnamate) on liquid crystal orientation stability,” Jpn. J. Appl. Phys. 44(13), L412–L415 (2005). [CrossRef]
  11. S.-J. Sung, K.-Y. Cho, H. Hah, J. Lee, H.-K. Shim, and J.-K. Park, “Two different reaction mechanisms of cinnamate side groups attached to the various polymer backbones,” Polymer (Guildf.) 47(7), 2314–2321 (2006). [CrossRef]
  12. D. Ahn, Y.-C. Jeong, S. Lee, J. Lee, Y. Heo, and J.-K. Park, “Control of liquid crystal pretilt angles by using organic/inorganic hybrid interpenetrating networks,” Opt. Express 17(19), 16603–16612 (2009). [CrossRef] [PubMed]
  13. S.-J. Sung, J. Lee, K.-Y. Cho, W. S. Kim, H. Hah, H.-K. Shim, and J.-K. Park, “Effect of photoreactivity of polyimide on the molecular orientation of liquid crystals on photoreactive polymer/polyimide blends,” Liq. Cryst. 31(12), 1601–1611 (2004). [CrossRef]
  14. S.-J. Sung, J.-W. Lee, H.-T. Kim, and J.-K. Park, “Photo-induced liquid crystal alignment on polyimide containing fluorinated groups,” Liq. Cryst. 29(2), 243–250 (2002). [CrossRef]
  15. S.-J. Sung, H.-T. Kim, J.-W. Lee, and J.-K. Park, “Photo-induced liquid crystal alignment on polyimide containing fluorine group,” Synth. Met. 117(1-3), 277–279 (2001). [CrossRef]
  16. H. Hah, S.-J. Sung, K. Y. Cho, and J.-K. Park, “Molecular orientation of liquid crystal on polymer blends of coumarin and naphthalenic polyimide,” Polym. Bull. 61(3), 383–390 (2008). [CrossRef]
  17. Y. Iimura, T. Saitoh, S. Kobayashi, and T. O. R. U. Hashimoto, “Liquid crystal alignment on photopolymer surfraces exposed by linearly polarized UV light,” J. Photopolym. Sci. Technol. 8(2), 257–262 (1995). [CrossRef]
  18. J. B. Kim, J. R. Lim, J. S. Park, H. J. Ahn, M. J. Lee, S. J. Jo, M. Kim, D. Kang, S. J. Lee, Y. S. Kim, and H. K. Baik, “The directional peeling effect of nanostructured rigiflex molds on liquid-crystal devices: liquid-crystal alignment and optical properties,” Adv. Funct. Mater. 18(8), 1340–1347 (2008). [CrossRef]
  19. M. Schadt, K. Schmitt, V. Kozinkov, and V. Chigrinov, “Surface-induced parallel alignment of liquid crystals by linearly polymerized photopolymer,” J. Appl. Phys. 31(Part 1, No. 7), 2155–2164 (1992). [CrossRef]
  20. T. J. Scheffer and J. Nehring, “Accurate determination of liquid-crystal tilt bias angles,” J. Appl. Phys. 48(5), 1783–1792 (1977). [CrossRef]
  21. H. Hillborg, N. Tomczak, A. Olàh, H. Schönherr, and G. J. Vancso, “Nanoscale hydrophobic recovery: A chemical force microscopy study of UV/ozone-treated cross-linked poly(dimethylsiloxane),” Langmuir 20(3), 785–794 (2004). [CrossRef] [PubMed]
  22. A. J. Kinloch, Adhesion and adhesives: science and technology (Chapman and Hall, 1987).
  23. D. K. Owens and R. C. Wendt, “Estimation of the surface free energy of polymers,” J. Appl. Polym. Sci. 13(8), 1741–1747 (1969). [CrossRef]

Cited By

Alert me when this paper is cited

OSA is able to provide readers links to articles that cite this paper by participating in CrossRef's Cited-By Linking service. CrossRef includes content from more than 3000 publishers and societies. In addition to listing OSA journal articles that cite this paper, citing articles from other participating publishers will also be listed.

« Previous Article  |  Next Article »

OSA is a member of CrossRef.

CrossCheck Deposited