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Fig. 55
Supermolecular material
47
which possesses a “boojum-like” structure and ex-
hibits a chiral nematic phase
texture (see Fig. 56). From the Grandjean plane texture, the twist sense of the
helical structure was found to be left-handed. The pitch was determined by
measuring the number of pitch bands per unit length from the fingerprint tex-
ture. A value of 2.0
m for the pitch length was obtained at room temperature.
The value was found to be similar to those of the chiral mesogen unit (1.7
µ
µ
m)
and the malonate precursor (1.9
m). Thus the fullerene moiety is shielded
very effectively among the laterally attached mesogens, without disturbing the
helical supramolecular organization of the mesophase. Furthermore, as the
mesogenic units are symmetrically distributed all over the fullerene sphere
they effectively isolate it, thereby decreasing the possibility of aggregation of
the C
60
units, which is detrimental to mesophase formation.
µ
Fig. 56 a
fingerprint texture for an uncovered droplet of compound
47
,and
b
the Grand-
jean texture of the chiral nematic phase
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