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Fig. 8
Induction of the mesophase in rod-coil molecules via hydrophobic forces
(Fig. 8). Small-angle X-ray diffraction in the optically isotropic state revealed
a strong primary peak together with a broad peak of weak intensity at about
1.8 relative to the primary peak position, indicating that the spatial distribu-
tion of centers of the spherical micelles has only liquid-like short range order,
most probably due to random thermal motion of spherical micelles [68, 69].
From the observed primary peak of X-ray diffraction, the diameter of spheres
was estimated to be approximately 12 nm. Considering that diblock rod-coil
molecule (
8
) with 22 EO repeating units shows only an isotropic phase after
crystalline melting, it is likely that hydrophobic forces play an important role
in the self-assembly of the molecules into discrete nanostructures.
A novel strategy for manipulating the supramolecular nanostructure may
be accessed by binding the C coil block of a coil-rod-coil ABC triblock
molecule (
9
)intoatetrabranchedtriblockmolecule(
10
)ataspecificcoilvol-
ume fraction [70]. This binding may slightly modify the entropic contribution
of the coil C part in the coil-rod-coil ABC system. In comparison with the
monomer, the tetramer has restricted chain end mobility through covalent
linkage. Consequently, this effect may bring about the formation of a novel
supramolecular nanostructure. Tetramerization of the molecule
9
provides
an unusual example of the formation of a 3D tetragonally perforated lamel-
lar liquid crystalline phase as an intermediate phase between conventional
lamellar and columnar structures (Fig. 9). The supramolecular structure con-
sists of liquid crystalline rod layers with in-plane tetragonally ordered coil
perforations stacked in an AB-BA sequence. The perforations are likely to be
filled by docosyl chains, most probably due to the large chemical difference
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