Thermal hysteresis and thickness dependence of the molecular orientation of poly(di-n-hexylsilane) in the film state.
Molecular orientation of poly(di-n-hexylsilane) adsorbed on poly(vinyl alcohol) film has been studied by making use of the stretching technique. Dichroic ratio, Rd, strongly depended on the thickness of poly(di-n-hexylsilane) thin film and the highest value ca. 19 was observed at the film thickness of 110 +/- 30 nm. The thermal hysteresis of the molecular orientation was observed in the heating-cooling cycles. By studying the fluorescence spectrum it was confirmed that a portion of the poly(di-n-hexylsilane) molecules were in transoid conformation even at 320 K, although most of poly(di-n-hexylsilane) molecules were in disordered conformation (conformation D). This poly(di-n-hexylsilane) in transoid conformation is formed in the stretching process and may play a role of crystallization nucleus to induce the whole orientation of the poly(di-n-hexylsilane) in the film state.
Horiuchi
Hiroaki
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Department of Chemistry, Gunma University, Kiryu, Gunma 376-8515, Japan. horiuchi@chem.gunma-u.ac.jp
Ishihara
Tomihiko
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Tsunoda
Shin-ichi
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Morishita
Daisuke
D
Takei
Tomoyuki
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Okutsu
Tetsuo
T
Seko
Toshihiro
T
Sugino
Hiroaki
H
Kawakami
Yasuyuki
Y
Watanabe
Hamao
H
Abe
Minoru
M
Takigami
Shoji
S
Hiratsuka
Hiroshi
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