Lyotropic chromonics

There is also a small family of LCs called lyotropic chromonic LCs that are in-between traditional thermotropic LCs and LLCs [10]. Lyotropic chromonic... 

LCs typically have an aromatic organic core with ionic groups lining the periphery, giving them a disk- or plank-like shape (e.g., ionic organic dye molecules). They are technically classified as LLCs because they can self-assemble into ordered phases in the presence of water. However, unlike traditional amphiphiles, lyotropic chromonic LCs are rigid rather than flexible, and their hydrophobic components are based on aromatic units rather than aliphatic chains. Unlike traditional amphiphilic LCs, they self-organize in so-... 

Fig.4 Structure of a typical lyotropic chromonic LC, and schematic representations of two lyotropic chromonic LC phases. Reproduced with permission from [10]. 2004 by Elsevier...

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... 

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... 

T. K. Attwood, J. E. Lydon, C. Hall, G. L. Tiddy. The distinction between chromonic and amphiphilic lyotropic mesophases. Liquid Cryst 7 657-668,1990. 

In addition to those formed by surfactant amphiphiles, two other types of lyotropic mesophases are generally recognized, neither of which exhibits a cmc. The first of these are lyotropic phases of rigid-rod polymers that can form mesophases in both aqueous and non-aqueous solvents " these mesophases are of the nematic or hexagonal type. Examples include polymeric metal acetylide complexes and DNA." The other type is usually formed from flat and largely aromatic molecules which stack to give lyotropic columnar phases, also referred to as chromonic phases." " This latter class is formed from systems with ionic or strongly hydrophilic peripheral functions, and forms mesophases... 

Among vast varieties of lyotropic LCs, chromonic mesophases are the families of new research target starting only about two or three decades ago. The properties are different from those of ordinary lyotropic mesogens of surfactant type. The molecules constitute aromatic(s) in the center, and hydrophilic parts are scattered around the molecules rather than aliphatic structures. Therefore, they are rigid and planar disklike or planklike, rather than micelles of flexible molecular assemblies of ordinary surfactants. The molecules aggregate in solution to form... 

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. 

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]. 

A survey of chromic species, especially dyes, makes it clear that there is no need for the molecules to even approximate to circular discs, as might be expected if chromonic systems are regarded merely as lyotropic discotic phases extended blade-like molecules are capable of forming chromonic me-sophases with apparently perfect hexagonal order. 

Concerning the term chromonic, this word was coined to replace phrases such as lyotropic mesophases of the types formed by soluble aromatic mesogens . It was intended to echo the bis-chromone structure of DSCG and to carry connotations of dyes and chromosomes (and hence nucleic acids). It was also intended to mark Hart-shorne s studies of DSCG (which although by no means the first such mesophase system to be explored, was one of the most extensively examined), and it is to Norman Hartshome, who taught me and many others a love of optical microscopy, that I respectfully dedicate this chapter. 

Luckhurst potential, dimers 816 luminance, guest-host effect 272 lutetium, phthalocyanine ligands 924 lyotropic blue phases, chromonics 998 lyotropic systems... 

There are some specific amphiphile systems which form exceptionally stable pancake-like micelles which, as one might expect, give anisotropic solutions analogous to discotic nematic phases. Conversely, there are other lyotropic systems containing elongated stacks of aromatic molecules, i.e., chromonic systems, which are analogous to thermotropic calamitic nematic phases. 

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