The centers of its molecules tend to lie in layers in the smectic phase.  
The Maier-Saupe mean field theory and the Onsager hard-rod model are theories that predict phase transitions in them.  They can form from disc-shaped basic units that stack to form columns in the discotic columnar phase.  The cholesteric phase is the thermotropic type of these substances, whose lyotropic type includes those formed by the Tobacco Mosaic Virus.  The centers of its molecules tend to lie in layers in the smectic phase.  Its molecules are mostly oriented the same way but distributed randomly in the simplest phase, known as nematic.  FTP, identify this substance used in display devices.
The Maier-Saupe mean field theory and the Onsager hard-rod model are theories that predict phase transitions in them.  
liquid crystals