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Proceedings Paper

Macroscopic birefringence in liquid crystals from novel cyanobacterial polysaccharide with an extremely high molecular weight
Author(s): Maiko Okajima-Kaneko; Daisaku Hayasaka-Kaneko; Shinji Miyazato; Tatsuo Kaneko
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Paper Abstract

We report an efficient method for extraction of anionic polysaccharides (PS) from cyanobacteria, Aphanothece sacrum; we used a hot alkaline solution (0.01 N NaOH) as an elution solvent in the first step of the extraction and isopropanol as a precipitation solvent in the last step. Thin fibers of PS were obtained at a high yield (50-80 % to the weight of the raw cyanobacterial sample). The spectroscopy and elemental analyses indicated the PS contains fucose, uronic acids (14.2 % by a carbazole-sulfuric acid method), a sugar unit containing amides. The solution of PS with a concentration of 1 wt% showed a very high viscosity (80 000cps) implying a high molecular weight, and a strong macroscopic birefringence with a texture typical of nematic liquid crystals was confirmed by crossed-polarizing microscopy (more than 0.5 wt%). The PS from A. sacrum may form a special structure rigid-rod enough to show LC phase and macroscopic birefringence.

Paper Details

Date Published: 9 May 2007
PDF: 8 pages
Proc. SPIE 6587, Liquid Crystals and Applications in Optics, 658711 (9 May 2007); doi: 10.1117/12.722235
Show Author Affiliations
Maiko Okajima-Kaneko, Japan Advanced Institute of Science and Technology (Japan)
Daisaku Hayasaka-Kaneko, The Univ. of Tokyo (Japan)
Shinji Miyazato, Japan Advanced Institute of Science and Technology (Japan)
Tatsuo Kaneko, Japan Advanced Institute of Science and Technology (Japan)

Published in SPIE Proceedings Vol. 6587:
Liquid Crystals and Applications in Optics
Milada Glogarova; Peter Palffy-Muhoray; Martin Copic, Editor(s)

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