| Co-Investigator(Kenkyū-buntansha) |
YAMAMOTO Takashi Yamaguchi University, Faculty of Science, Professor, 理学部, 教授 (00127797)
ASAHI Takanao Yamaguchi University, Faculty of Science, Professor, 理学部, 教授 (30184154)
URAKAMI Naohito Yamaguchi University, Faculty of Science, Lecturer, 理学部, 講師 (50314795)
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| Budget Amount *help |
¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 2004: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 2003: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 2002: ¥2,000,000 (Direct Cost: ¥2,000,000)
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| Research Abstract |
Structure formations of hydrocarbon molecules, which are considered to play an important role in the structure formation in soft material systems, have been investigated by means of experimental methods and computer simulations. We mainly focus on n-alkane thin film system, characteristic high-temperature "rotator phase" of bulk n-alkane crystals, bulk n-alkanethiol ciystals, polypropylene crystals, and some chain molecular model system. The major results in these studies are as follows. 1. In chain molecular thin film system, typical two molecular orientation states, "normal orientation", in which the molecular chain axes are normal to the substrate surface, and "parallel orientation", in which the molecular axes are parallel to the substrate surface, are commonly observed. The evaporation condition dependence of the molecular orientation has been investigated systematically. When the evaporation rate is slow and/or the substrate temperature is high, the normal orientation state tends
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to appear. The normal orientation is considered to be most stable state in n-alkane thin film on substrates used here. The strong substrate dependence, which is caused by the kinetics during the deposition, is also confirmed. 2. In the rotator phase of n-alkanes, the results of the x-ray diffuse scattering study shows that the hydrocarbon chains make two kinds of fluctuations, the rotational motion around the chain axes and the translational motion along the axes, and they have short-range correlations each other. 3. In n-alkanethiol system, the complicated polymorphism, which is cased by the weak SH-SH interaction at the end of hydrocarbon chain, is observed. 4. In isotactic polypropylene, which is 3/1 helical structure as most stable conformation, the crystallization of γ phase has been investigated. It is interesting that the chains crystallize with crossing their chain axes. 5. The mechanism of the formation of the ordered structure in the rigid rod-like chain model system has been revealed by computer simulation. Less
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