Macroscopic birefringence in liquid crystals from novel cyanobacterial polysaccharide with an extremely high molecular weight

Maiko Okajima-Kaneko; Daisaku Hayasaka-Kaneko; Shinji Miyazato; Tatsuo Kaneko

doi:10.1117/12.722235

9 May 2007 Macroscopic birefringence in liquid crystals from novel cyanobacterial polysaccharide with an extremely high molecular weight

Maiko Okajima-Kaneko, Daisaku Hayasaka-Kaneko, Shinji Miyazato, Tatsuo Kaneko

Author Affiliations +

Proceedings Volume 6587, Liquid Crystals and Applications in Optics; 658711 (2007) https://doi.org/10.1117/12.722235
Event: International Congress on Optics and Optoelectronics, 2007, Prague, Czech Republic

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.

Citation Download Citation

Maiko Okajima-Kaneko, Daisaku Hayasaka-Kaneko, Shinji Miyazato, and Tatsuo Kaneko "Macroscopic birefringence in liquid crystals from novel cyanobacterial polysaccharide with an extremely high molecular weight", Proc. SPIE 6587, Liquid Crystals and Applications in Optics, 658711 (9 May 2007); https://doi.org/10.1117/12.722235

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