Lyotropic Chromonic Liquid Crystals: Emerging Applications
Over the last 10 years since the early work of Attwood, Lydon, Tiddy, and co-workers [1–3] there has been a growing interest in a distinct family of lyotropic liquid crystals (LCs), the so-called lyotropic chromonic liquid crystals (LCLCs). LCLCs represent a broad but not well-understood class of soft matter in which the reversible self-assembled aggregates formed by non-amphiphilic molecules show liquid crystalline phases [4–7]. The range of materials which forms chromonic LC phases includes drugs [2, 3, 8–10], dyes [11–14], and DNA nucleotides, such as guanosine derivatives [15, 16]. The name “chromonic” was suggested by Lydon to carry connotations of dyes and chromosomes and of the bis-chromone structure of disodium cromoglycate (DSCG), also known as an anti-asthmatic drug cromolyn or INTAL, one of the first studied LCLCs [3, 5].
The LCLC molecules have a plank-like or disk-like polyaromatic central core with polar groups at the periphery. The geometry of the basic structural unit in LCLCs is different from spherical or cylindrical micelles and bilayers formed by amphiphilic molecules in the conventional lyotropic LCs. In water, the chromonic molecules typically stack on top of each other face-to-face (the so-called H-aggregation) to minimize the areas of unfavorable contact with water ...