Chromonic Liquid Crystals

What is the discotics for the thermotropic liquid crystals that is the lyotropic chromonic liquid crystals (LCLCs) for the lyotropic materials. LCLC molecules are plank-like rather than rod-like, rigid rather than flexible, aromatic rather than aliphatic. Typical LCLC molecules and their aggregation in 

According to Lydon, aggregation of LCLC molecules is a steady, progressive build-up of chromonic aggregates where the addition of a molecule to a stack is always associated with the same increment of free energy. On 

Molecular structure of a typical LCLC representative dye Blue 27, and the scheme of aggregation of the molecules in aqueous solutions. (Picture courtesy of O. Lavrentovich.) 

Since very little is known about LCLC structures and properties, the recognition of these materials is not widespread. However, as one of the pioneers in the field, J. Lydon, writes A single commercial application, however, could change this picture overnight. The liquid crystal literature will be as full of chromonic studies as it now is with ferroelectric chevron structures. Watch this space.  

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Chromoionophores, 20 517-518 Chromonema fibers, 17 612 Chromonic liquid crystals, 15 101 Chromophore interaction, in dye molecules, 20 511-512... 

Chromonic liquid crystals are a special class of lyotropic liquid crystals. Flat aromatic systems with polar substituents form columnar aggregates by n-n interactions in solution. The mesophases of concentrated DNA solutions or of copper-tetracarboxyphthalocyanine are examples for this. Special types of chiral mesophases have been observed [29]. 

J. Lydon, Chromonic liquid crystal phases, Curr. Opin. Colloid Interface Sci., 3(5),... 

C.J. Woolverton, G.D. Niehaus, K.J. Doane, O. Lavrentovich, S.R Schmidt, S.A. Signs, Detection of ligands with signal amplification, U.S. Patent 6,171,802 (February 2001) O.D. Lavrentovich and T. Ishikawa, Bulk alignment of lyotropic chromonic liquid crystals, U.S. Patent 6,411,354 (June 25, 2002). 

Lavretovich, O. D. Schneider, T. Golovin, A. B. Lee, J. C. A design and fabrication of an aligned lyotropic chromonic liquid crystal films with improved optical properties and aUgmnent uniformity. U.S. Pat. Appl. Publ. US 2006040069, 2006 Chem. Abstr. 2006,144, 243534. 

Schneider T, Artyushkova K, Fulghum JE, Broadwater L, Smith A, Lavrentovich OD. Oriented monolayers prepared from lyotropic chromonic liquid crystal. Langmuir... 

Matsunaga D, Tamaki T, Ichimura K. 2003. Azo pendant polyamides which have the potential to photoalign chromonic lyotropic liquid crystals. J Mater Chem 13 1558 1564. 

Up until the last twenty years, the family of chromonic mesophases lay hidden like an uncharted continent. Occasionally explorers returned to give some partial account, but their reports usually fell on deaf ears, and they were largely unaware of each other s discoveries. A coherent overall picture was remarkably late coming. It is signiflcant that in the 500 pages of the two-volume earlier attempt at a comprehensive survey of liquid crystals by Gray and Winsor, published in 1974, there is no mention whatsoever of the systems we now call chromonic [9]. 

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