| Perfluoropolymer as an Alignment Layer Liquid Crystals |
| In this talk, I will present some experimental results using perfluoropolymer as an alignment layer. We
found a strong discontinuous orientational transition (anchoring transition) in a nematic liquid-crystal with
a large transverse dipole moment1. The transition becomes continuous under an electric field and the
umbilic defects are formed2. The dynamics of umbilic defects will be discussed. Using discontinuous
anchoring transition in the rubbed cells, we will demonstrate a novel bistable memory device writable by a
laser beam3. The device utilizes the hysteresis of a temperature-driven discontinuous anchoring transition in
a dye-doped nematic liquid crystal. Finally we will also show that the perfluoropolymer can be used as a
shock-free homeotropic alignment for smectic liquid crystals4. References: 1. Surajit Dhara, J. K. Kim, S.M., Jeong. R. Kogo, F. Araoka, K. Ishikawa, and H. Takezoe, PHYSICAL REVIEW E 79, 060701(R)(2009). 2. T. Arun Kumar, Surajit Dhara, K. Ishikawa, and H. Takezoe (submitted). 3. J. K. Kim, F. Araoka, S. M. Jeong, Surajit Dhara, K. Ishikawa, and H. Takezoe APPLIED PHYSICS LETTERS 95, 063505 (2009). 4. S. M. Jeong, J. K. Kim, F. Araoka, Y. Shimbo, Surajit Dhara, N.Y. Ha, K. Ishikawa, and H. Takezoe, Adv. Mater.21, 1 (2009). |