The most commonly used type of these materials can be modeled using Maier-  
Theories of these materials generally rely on a scalar order parameter defined as one half the average over the whole  ensemble of three cosine squared of theta minus one. Electroinstability in one form of these materials is alternately named  for Helfrich. Two widely studied examples of these materials are 5CB and the E7 mixture. Although not polymers,  differential scanning calorimetry is commonly used to study these materials. de Gennes introduced a Landau type of  phase-transition theory for these materials. The most commonly used type of these materials can be modeled using Maier-  Saupe's mean field theory or (*) Onsager's theory, both of which treat the constituents of these materials as rigid rods. Those of  these materials in the cholesteric phase tend to align in a helical manner, but otherwise have identical properties as the nematic  phase. For 10 points, name this state of aggregation that is intermediate between a crystalline solid and an amorphous liquid.
Theories of these materials generally rely on a scalar order parameter defined as one half the average over the whole  ensemble of three cosine squared of theta minus one.
liquid crystals [or mesogens]