Liquid Crystalline Assembly of Rod–Coil Molecules - Liquid Crystalline Functional Assemblies and Their Supramolecular Structures - page 70

Fig. 5 Liquid crystalline structures formed by wedge-shaped molecules depend on the
length of PEO
the chains being required while maintaining the radial arrangement of the
rigid segments. Consequently, the discrete PEO domains will be extended
to an infinitely long cylindrical domain in which the coils are less con-
fined, which results in the formation of a 2D hexagonal columnar structure.
Further increasing the length results in the rigid wedge-shaped segments as-
sembling into a perforated lamellar structure with a radial arrangement of
rigid segments, which allows a greater volume for the PEO chains to ex-
plore compared to that of the columnar structure. The radial arrangement
of the wedge-shaped rigid segments eventually transforms into a parallel ar-
rangement with interdigitation, to produce a flat interface while maintaining
a constant density of the rigid hydrophobic domain. This transformation re-
sults in a monolayer lamellar structure as in the case of a molecule based
on longest PEO chain.
Compared to other self-assembling systems based on dendritic mol-
ecules [46-48], the remarkable feature of the wedge-shaped building blocks
investigated is their ability to self-assemble not only into spherical cubic and
columnar structures, but also into an unusual bilayer lamellar structure with
in-plane hexagonally ordered coil perforations. This approach of control-
ling supramolecular structures using wedge-shaped building blocks and only