Supermolecular Liquid Crystals - Liquid Crystalline Functional Assemblies and Their Supramolecular Structures - page 40

Fig. 47 The 29 Si NMR spectrum of supermolecule 43 showing the resonances for four
identifiable silicon atoms

Compound 43 was found to exhibit a chiral nematic phase (see the tex-
ture in Fig. 48), hexagonal disordered columnar (see Fig. 49) and rectangular
disordered columnar phases, in the sequence g 5.4 Col rd 30 Col hd 102.3 N ∗
107.7 ◦ C Iso Liq [94]. Thus the increase in the number density of the meso-
gens bound to the central scaffold transforms the situation from the octamers
41 and 42 , which exhibit calamitic phases, to one where the hexadecamer
43 exhibits columnar phases. However, the formation of columnar phases
when the dendrimer possesses rod-like mesogenic groups is not easy to vi-

Fig. 48 The Grandjean plane texture of the chiral nematic phase of supermolecule 43 .
There is a blue iridescent color which is due to the selective reflection of light from the
helical macrostructure ( × 100)