Halogen-bonded Liquid Crystals - Halogen Bonding: Fundamentals and Applications - page 164

Fig. 4 Schematic representation of the molecular organisation in three common columnar
phases
creases with increasing temperature), then the reflected colour also changes
and so chiral nematic liquid crystals (also sometime known as cholesteric
liquid crystals) find application in temperature sensing.
Discotic liquid crystals on the other hand are based around a fairly flat core
structure and are generally surrounded by six or eight peripheral alkyl(oxy)
chains. Examples are given in Fig. 3.
A nematic phase of discotic molecules exists where the short molecular
axes are correlated directionally but this phase is still rather rare. By far and
away the most common behaviour is for the molecules to stack in columns,
which are then arranged in a particular way with respect to one another [7].
Examples are given in Fig. 4.
2.2
High Molar Mass Liquid Crystals
In general terms, high molar mass liquid crystals are classified according to
the location of the mesogenic unit in the polymer. Thus, they are either incor-
porated into the main chain (main-chain liquid crystal polymers - MCLCP;
Fig. 5A) or they are pendant from the main chain (side-chain liquid crystal
polymers - SCLCP; Fig. 5B).