In summary, this work proposes for the first time an Az
analogue of a photoresponsive calamitic LC molecule based
on CPD, whose structure differs only in one ring of the
mesogen, namely, cyclohexenyl for CPD or phenyl for Az.
The similarities and differences between the two rod-like
photoresponsive molecules presented in this work are expected
to expand the design and choice of photoresponsive LC
systems. Extended studies in polymer systems will be attractive
in terms of device applications.
This work was supported by a Grant-in-Aid for Scientific
Research on Priority Areas ‘‘Photochromism (no. 471),’’ and
‘‘Scientific Research (B) (19350053)’’ from the Ministry of
Education, Culture, Sports, Science and Technology, Japan.
Notes and references
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Fig. 4 The photoinduced nematic to isotropic phase transition
observed by POM. A sandwiched cell (4 mm spacer) of 5CB containing
4 mol% 5CPDCN was placed on a temperature controlled stage at
34 1C. Spot irradiation (diameter: 350 mm) was achieved in the center.
2 K. Ichimura, Y. Suzuki, T. Seki, A. Hosoki and K. Aoki, Langmuir,
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Schlieren texture over the entire area (POM image at 0 s).
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of both photoisomerization behavior and molecular assembly
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phase transition in the 5CPDCN LC system. This fact is a
distinct difference from that seen for Az systems. In this way,
the phase switching behavior is similar but the working
wavelength is clearly distinguished for Az systems.
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This journal is The Royal Society of Chemistry 2009
3794 | Chem. Commun., 2009, 3792–3794