Supermolecular Liquid Crystals - Liquid Crystalline Functional Assemblies and Their Supramolecular Structures - page 13

tachment, and the degree to which they are decoupled from the scaffold. For
example, the density of mesogenic groups attached to the periphery can ef-
fectively change the overall gross shape of the structure of the supermolecule
from being rod-like, to disc-like, to spherulitic. Thus, the structure of the
systems at a molecular level can be considered as being deformable, where
each type of molecular shape will support different types of self-organized
mesophase structure. Thus, for supermolecular materials, rod-like systems
will support the formation of calamitic mesophases (including the various
possibilities of smectic polymorphism), disc-like systems tend to support
columnar mesophases, and spherulitic systems form cubic phases, as shown
in Fig. 14.
Similar structure-self-organizing properties are also found for supramo-
lecular systems, and indeed in some cases far more complex polymorphism
and a richer variety of mesophase types are found [55-57]. Although there
have not been extensive research studies into the effects that the type (rod-
like, disc-like or spherulitic) of mesogenic group attached to the central scaf-
fold has on mesophase formation, it is clear for rod-like shaped mesogenic
groups that the orientation of the attachment can markedly influence the type
of mesophase formed and polymorphism of any smectic phases formed. As
with side-chain liquid crystal polymers (SCLCPs), lateral attachment (side-
on) of the mesogenic units often leads to supermolecular systems exhibiting
Fig. 14 Effect of the number density of mesogens on the surface of the supermolecular
structure on the formation of various mesophases