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Home > Research Activities > Other Liquid Crystals

Other Liquid Crystals

Our research on liquid crystals is in a wide range. The followings are the summary of some of these.

1. Cholesteric liquid crystals
   
   Detailed measurements of the optical properties of cholesteric liquid crystals. We found the total reflection band, in which light with any polarizations is reflected, in addition to the selective reflection band at oblique incidence of light (1982-). These researches are followed by special phase matching of SHG (1998-) and photonic devices (2003-).

2. Ferroelectric and antiferroelectric and their subphases
   
   We clarified the structure of zig-zag structure in surface stabilized ferroelectric liquid crystals. We also studied the structures of twisted states. We encountered antiferroelectric liquid crystals during the course of studies of ferroelectric liquid crystals. We proposed a fast display device using tristable switching and demonstrated the performance (1988). Later we found that this is actually the antiferroelectric liquid crystal (1989). In addition to the antiferroeletric liquid crystal with a two-layered periodicity, ferroelectric phases with three- or four-layered periodicity. This field became a major field of liquid crystals.

3. Science of Liquid Crystal Surface
   
   We investigated liquid crystal surface; how do liquid crystals form oriented structure on treated surfaces, i.e., what kind of relationship exists between the strength of surface treatment and liquid crystal orientation distribution function, by measuring SHG, SHG interferometry, UV-Vis absorption and NEXAFS and by analyzing the results using maximum entropy method.

4. Other systems
   
   We found a cubic phase based on chiral recognition under the collaboration with Prof. Yoshizawa (Hirosaki Univ.) and Dr. Kusumoto (DIC)
   We fabricated switchable diffraction gratings using photocurable liquid crystals.
   Under the collaboration with Prof. Watanabe, we found that two liquid crystalline systems show polar nematic phase. They are polypeptide and aromatic polyester, which form rigid rod-like polymer liquid crystal. This could be of proper ferroelectric.

5. Switchable Columnar phase
   
   Under the collaboration with Prof. Gorecka (Univ. Warsow) and Prof. Kishikawa (Chiba Univ.), we conducted polar switchable columnar liquid crystals. They consist of banana-shaped liquid crystals and urea derivatives, respectively. We observed flexor behavior in the former columnar phase based on dielectric measurements. In the latter compound, we observed Kerr effect in the isotropic phase in the vicinity of the transition temperature to the Columnar phase.