- Alignment Control for Liquid Crystalline Polymer Films by Free-surface Modification
- Shusaku NAGANO and Takahiro SEKI
The orientations of liquid crystals are strongly influenced by the contacting surface. The orientational control of LC is crucial for the fabrication of LC devices such as display, optical and memory devices. Generally, the control of the LC orientation and alignment is conducted by the modification of the substrate surfaces. Our recent work demonstrated an approach to control the LC orientation
from the free surface side in liquid crystalline polymer films by using surface segregation of polymer chains. The approach is versatile for the orientational control for LC polymer and LC block copolymer systems. This article reviews the orientational control of the LC polymer
systems from the free surface side with focusing on our approaches.
Keywords: Polymer Liquid Crystal, Polymer Surface, Liquid Crystal Alignment, Photoalignment, Surface Segregation
- Recent Progress in Photoalignment Technology and Mechanical Analysis of Film
- Atsushi SHISHIDO
This review describes our recent progress in photoalignment technology and mechanical analysis method of surface strain in bending films. Photochemical and photophysical molecular-alignment methods play an important role in development of display and photoactuators. We show that polymer stabilization of dye-doped liquid crystals lowers threshold light intensity to induce photophysical
molecular alignment. In addition, photochemical isomerization of azobenzene and the resultant molecular alignment change in film are discussed from the viewpoint of photoactuation.
Keywords: Photoalignment, Bending, Film, Mechanical Analysis, Surface Strain
- Ion-controlled Color Change Device using Hydroxypropyl Cellulose LC
- Sadahito UTO and Yui KIMBARA
Hydroxypropyl cellulose (HPC) aqueous solution has cholesteric liquid crystal phase and is colored by a selective reflection. Because the wavelength of the selective reflection depends on the kind and concentration of an additive ion, the color can be changed by applied voltage which can change a local concentration by electrophoresis. However, to realize the industrial application of this electrooptic effect, there are many problems that must be solved. In this article, the color control of reflection wavelength was improved by new method.
Keywords: Hydroxypropyl Cellulose, Reflection, Color Change, Flexible, Lyotropic Cholesteric
- Photoresponsive Macrocyclic Liquid-crystalline Materials and Photoresponsive Crystal-to-liquid Phase Transition Materials
- Yasuo NORIKANE
In this article, our recent progress of organic materials that liquefies upon light irradiation is described, especially in their background, concept, and future prospect of the material in academic and applied aspects. Photoisomerization of azobenzene has been well known and it has been utilized in photoresponsive liquid-crystal materials. However, the photoisomerization of azobenzene in the crystalline phase has not been well studied. During the course of our study in liquid-crystalline macrocyclic azobenzene systems, we have found that these compounds show photoisomerization in the crystalline state as well as liquidcrystalline state and it triggers liquefaction of the crystals. Variation of molecular structure and their potential application in reversible adhesives and simple photolithographic processes are described.
Keywords: Azobenzene, Photoisomerization, Crystal, Liquid, Phase Transition
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- Volume 19 Number 1（January 25, 2015）