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Fig. 3
Molecular structure of a rod-coil-rod twin mesogenic molecule containing an
oligo(ethylene oxide) moiety, and its self-organized structure
surfaces was achieved. In the aligned LC smectic A phase, the ratio of ionic
conductivities parallel and perpendicular to the smectic layer was 1.3
10
4
.
Two-dimensional ion conduction was also achieved for the smectic liquid
crystals consisting of the mixture of ionic liquids and hydroxyl-functionalized
rod molecules [49-51] and smectic LC imidazolium salts having a long alkyl
chain [52-55]. One-dimensional ion conduction was performed for aligned
columnar LC phases forming ion-channels of fan-shaped imidazolium salts
having a tris(alkoxy)phenyl moiety [56].
×
2.3
Nanostructured Liquid-Crystalline Polymers
Side-chain LC poly(siloxane)s
3
were prepared by Hsiue et al. (Fig. 4) [61].
The mesogenic side chains are linked to the siloxane backbone through
oligo(ethylene oxide) moieties. These complexes with several alkali metal
salts show relatively high ionic conduction in the order of 10
-6
Scm
-1
at ambi-
ent temperature. Percec prepared LC poly(siloxane)s
4
for potential use as 1D
ion conductors [62]. Although no ionic conductivities were reported for these
LC polymers, a possibility of an ion channel formed by poly(siloxane)s, which
hold nematogenic side chains as shown in Fig. 5, was suggested. In this case,
the mesogen is connected to the polymer main chain at the lateral position
via an oligo(ethylene oxide) chain, and therefore the flexible poly(siloxane)
is surrounded by the oligo(ethylene oxide) moieties and mesogenic groups,
inducing a 1D structure.
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