2002 Fiscal Year Final Research Report Summary
Stabilization of Surfactant-Free Emulsion and its Application for Novel Reaction Field
| Project/Area Number |
12640565
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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 |
機能・物性・材料
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| Research Institution | Tokyo University of Science |
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Principal Investigator |
ABE Masahiko Tokyo University of Science, Faculty of Science and Technology, Professor, 理工学部, 教授 (40089371)
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| Co-Investigator(Kenkyū-buntansha) |
SAKAI Hideki Tokyo University of Science, Faculty of Science and Technology, Lecturer, 理工学部, 講師 (80277285)
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| Project Period (FY) |
2000 – 2002
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| Keywords | Emulsion / Oid Droplet / Alkane / Interfacial tension / Zeta Potential / Dispersion Stability / Activated Oxygen / Ultrasonication |
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| Research Abstract |
Growth processes of hydrocarbon droplets (06-016: n-hexane, cyclohexane, n-octane, n-decane, n-dodecane, n-tetradecane, and n-hexadecane) in oil/water emulsions under surf actant-free conditions were examined by dynamic light scattering (DLS) and freeze-fracture electron microscopy (FFEM). DLS results showed that the growth rate of droplet size decreased with, increase in hydrocarbon chain length. For example, n-hexane droplets grew within 1 h from submicrometer to micrometer droplets, while n-hexadecane droplets with sizes of several tens of nanometers kept their dispersibility for 24 h. The growth processes were determined as coalescence and molecular diffusion (Ostwald ripening) in terms of the Lifshitz-Slyozov-Wagner theory and the Smoluchowski equation. Furthermore, FFEM was used to examine the growth mechanism in detail. Direct imaging of n-hexane and cyclohexane droplets by FFEM allowed us to observe very fine oil droplets (ca.10 nm in diameter) though DLS could not detect these droplets, suggesting that fine droplets of shorter hydrocarbons such as n-hexane and cyclohexane grow via both molecular diffusion and coalescence processes in a very short time after preparation.
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