| Project/Area Number |
14540305
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
固体物性Ⅰ(光物性・半導体・誘電体)
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| Research Institution | HIROSHIMA UNIVERSITY |
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Principal Investigator |
SATO Kiyotaka Hiroshima University, Graduate School of Biosphere Science, Professor, 大学院・生物圏科学研究科, 教授 (80034479)
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| Co-Investigator(Kenkyū-buntansha) |
UENO Satoru Hiroshima University, Graduate School of Biosphere Science, Associate Profes, 大学院・生物圏科学研究科, 助教授 (50243605)
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| Project Period (FY) |
2002 – 2003
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| Project Status |
Completed (Fiscal Year 2003)
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| Budget Amount *help |
¥3,000,000 (Direct Cost: ¥3,000,000)
Fiscal Year 2003: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 2002: ¥2,300,000 (Direct Cost: ¥2,300,000)
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| Keywords | template / heterogeneous nucleation / Synchrotron radiation X-ray analysis / alkane crystals / emulsion / 添加物効果 |
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| Research Abstract |
The principal aim of this research project was to clarify the mechanisms of heterogeneous nucleation of organic crystals that were induced by the presence of templates. The growth systems examined were bulk solution in which thin films prepared by physical vapor deposition were put as the template, and oil-in-water (0/W) emulsion in which hydrophobic surfactants with high-melting points were added. The in-situ observation of the nucleation processes were done by using Synchrotron radiation X-ray beam couples with DSC, both were analyzed at the same time for the same sample. The organic substances employed in the present work were n-alkanes with different carbon numbers, triacylglycerols and vegetable fats. The following results were obtained
1) In the O/W emulsion made of n-alkanes, triclinic crystals were nucleated without the template additives. However, pseudo-hexagonal-orthorhombic crystal was nucleated prior to triclinic polymorph. This is ascribed to the template films of the additives that were preferentially crystallized before the nucleation of n-alkanes
2) In the O/W emulsion made of triacylglycerols, alpha crystals were nucleated without the additives. The addition of the additives, however, induced the nucleation of beta-prime crystals. This result was also interpreted with the help of the template films formed at the oil-in-water interface
3) In the bulk solution, orientation, polymorphism and rate of nucleation were modified by the presence of the template thin films
The above results were discussed in a theory of heterogeneous nucleation Induced by the template films. The template effect in the emulsion was revealed by the freezing of the hydrophobic chains with high-melting points. The template effects in the bulk solution showed epitaxial relationships of the template and newly-formed crystals
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