Supramolecular Interactions in the Formation of Thermotropic Liquid Crystalline Polymers - Liquid Crystalline Functional Assemblies and Their Supramolecular Structures - page 123

a self-assembling (A-B) n polymer (Fig. 3b). However, homoditopic monomers,
which have one of the complementary units placed on both ends of the core
(e.g. A-A or B-B), will only exhibit polymer-like properties upon mixing the
two complementary monomers (e.g., Fig. 3c). In all the above examples the core
is mesogenic; however, this does not necessarily have to be the case. An addi-
tional subset of main-chain SLCPs involves aggregates in which the mesogenic
component is the supramolecular motif itself. Such supramolecular mesogens
can, of course, be formed through either self-complementary units or with (as
is shown in Fig. 3d) a hetero-supramolecular motif. An alternative approach is
to use ditopic molecules that interact through two faces of a rigid, usually disk-
like component (Fig. 3e), rather than through the ends of a chain. This leads to
1-dimensional polymeric structures which tend to form columnar LC phases.
Pre-made polymer backbones with supramolecular binding sites can be
used to access side-chain SLCPs with a monotopic small mesogenic molecule
(Fig. 3f). Similar architectures are accessed if the supramolecular motif itself
is mesogenic (Fig. 3g). If the supramolecular motif is mesogenic and one of
its components is part of the polymer backbone, then the addition of its com-
plement will yield side-chain SLCPs whose mesogen consists of part of the
main-chain as well as the side chain (Fig. 3h). Alternatively, a small mesogen-
containing molecule can access side chain SLCPs if the supramolecular motif
can form polymeric tape-like structures (Fig. 3i). The use of oligotopics that
areeithersmallmolecules(Fig.3j)orpolymers(Fig.3k)ratherthanditopic
monomers can access LC branched or network structures. Of course, in the
Fig. 4 A selection of some supromolecular motifs used to access supramolecular liquid
crystals