Helical Polyacetylene Synthesized with a Chiral Nematic Reaction Field
K. Akagi,
*
G. Piao,
S. Kaneko,
K. Sakamaki,
H. Shirakawa,
*
M. Kyotani
Helical polyacetylene was synthesized under an asymmetric reaction
field consisting of chiral nematic (N*) liquid crystals (LCs). The
chiral nematic LC was prepared by adding a chiroptical binaphthol
derivative as a chiral dopant to a mixture of two nematic LCs.
Acetylene polymerizations were carried out using the catalyst titanium
tetra-n-butoxide-triethylaluminum dissolved in the chiral nematic LC solvent. The polyacetylene film was shown by scanning electron microscopy to consist of clockwise or counterclockwise helical
structure of fibrils. A Cotton effect was observed in the region of the
* transition of the polyacetylene chain in circular
dichroism spectra. The high electrical conductivities of ~1500 to
1800 siemens per centimeter after iodine doping and the chiral helicity
of these films may be exploited in electromagnetic and optical
applications.
K. Akagi, G. Piao, H. Shirakawa, Institute of Materials Science
and Center of Tsukuba Advanced Research Alliance, University of
Tsukuba, Tsukuba, Ibaraki 305-8573, Japan. S. Kaneko, K. Sakamaki,
Institute of Materials Science, University of Tsukuba, Tsukuba, Ibaraki
305-8573, Japan. M. Kyotani, National Institute of Materials and
Chemical Research, Tsukuba, Ibaraki 305-0046, Japan, and Center of
Tsukuba Advanced Research Alliance, University of Tsukuba, Tsukuba,
Ibaraki 305-8577, Japan.
*
To whom correspondence should be addressed. E-mail:
akagi{at}ims.tsukuba.ac.jp (K.A.) and
hideki{at}ims.tsukuba.ac.jp (H.S.)
