ABSTRACT
The existence of mesophases generated by disc-shaped molecules was theoretically predicted in 1970 and mesomorphism in discotic materials was first reported in 1977 by Chandrasekhar. Discotic liquid crystal mesomorphism has been found for a range of materials based on the tricycloquinazoline core, which is a fairly large polyaromatic heterocyclic core. Discotic architectures that use a central triphenylene core with six peripheral triphenylene units also exhibit columnar mesophases, and these are commonly called star-like liquid crystals. Discotic materials can also generate a nematic phase and, as for calamitic materials, only one nematic phase exists. The core systems shown so far have all been aromatic. However, disc-shaped molecules can be generated from alicyclic core structures. The disc-shaped central core unit is usually benzene or a polyaromatic such as triphenylene or phthalocyanine, but columnar phases have been generated with alicyclic cores such as cyclohexane and carbohydrate.
