| Project/Area Number |
10440210
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| Research Category |
Grant-in-Aid for Scientific Research (B).
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
機能・物性・材料
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| Research Institution | KYUSHU UNIVERSITY |
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Principal Investigator |
ARATONO Makoto KYUSHU UNIVERSITY, Faculty of Sciences, Prof., 大学院・理学研究院, 教授 (20175970)
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| Co-Investigator(Kenkyū-buntansha) |
IKEDA Norihiro Fukuoka Women's University, Faculty of Human Environmental Science, Ass.Prof., 人間環境学部, 助教授 (30211030)
TAKIUE Takanori KYUSHU UNIVERSITY, Faculty of Sciences, Assistant, 大学院・理学研究院, 助手 (40271100)
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| Project Period (FY) |
1998 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥9,900,000 (Direct Cost: ¥9,900,000)
Fiscal Year 2000: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 1999: ¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1998: ¥6,500,000 (Direct Cost: ¥6,500,000)
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| Keywords | vesicle / vesicle-micelle transition / surface tension / phase diagram of vesicle formation / surfactant mixtures / 相図 / 示差走査熱量計 / 界面熱力学 / 界面活性剤 |
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| Research Abstract |
1. The phase behavior of a very dilute aqueous solution of a sodium dodecyl sulfate (SDeS)-decyltrimethylammonium bromide (DeTAB) mixture was investigated by the surface tension measuremnt an partly by the density measurement. The surface tension and density were measured as functions of total molality of surfactant m and composition of DeTAB, X.Break points were observed on the curves and identified as the critical vesicle concentration and the concentration of the initial and final points of the vesicle-micelle coexisting region, respectively. These break points were plotted against X, analyzed thermodynamically, and then the compared with the ones in the diagrams predicted from a simple model. The composition of DeTAB in the vesicle at the critical vesicle concentration, CVC, was obtained from the CVC vs X curve, and it was found out to be 0.5 at almost X values. From the other break point versus X plots, the composition region of the vesicle-micelle coexistence in the phase diagram was suggested to be from 0.62 to 0.65. Furthermore, vesicle formation was clearly indicated to take place even at X=0.9999, and therefore, the vesicle-micelle transition on the critical aggregation concentration versus X curve was expected to sit between X=0.9999 and 1.
2. The surface tension of aqueous solution of decyltrimethylammonium decyl sulfate (DeTADeS) was measured as a function of temperature at various molalities under atmospheric pressure. DeTADeS has been found to form equilibrium multilamellar vesicles spontaneously. The surface density, the entropies of adsorption and the entropy of vesicle formation are evaluated. The mechanism of formation of equilibrium vesicle is investigated from the standpoint of thermodynamics and from the comparison of the results with those of the micelle forming systems.
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