2005 Fiscal Year Final Research Report Summary
Studies on coagulation process of colloidal systems stabilized by adsorption of amphiphilic materials
| Project/Area Number |
15550167
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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 |
Organic industrial materials
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| Research Institution | Kagawa University |
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Principal Investigator |
FUKADA Kazuhiro Kagawa University, Faculty of Agriculture, Professor, 農学部, 教授 (60212180)
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| Co-Investigator(Kenkyū-buntansha) |
FUJII Masatoshi Tokyo Metropolitan University, Faculty of Urban Liberal Arts, Research Associate, 都市教養学部, 助手 (60183927)
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| Project Period (FY) |
2003 – 2005
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| Keywords | Colloidal stability / emulsion / adsorption / surfactant / clay mineral / food protein / Atomic force microscope / surface force |
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| Research Abstract |
1.Dielectric, ultrasonic velocity, electrophoretic mobility, and cationic-surfactant-adsorption experiments were carried out on suspensions of montmorillonite clay exchanged with different types of counter-ions to understand the hydration, adsorption, and coagulation behaviors of the system. It was found the adsorption amount of surfactants became a maximum in a few hours after the addition and then gradually decreased approaching an equilibrium value. These results suggested that one should consider the kinetics of adsorption for the use of montmorillonite as an adsorbent to remove hydrophobic materials efficiently from waste water.
2.Emulsifying power and emulsion stability was investigated for some food proteins and sugar-based nonionic surfactants. Bovine serum albumin (BSA) could form more stable corn oil emulsions than β-lactoglobulin (β-Lg). We also confirmed that in the medium near pH 5 which closed to the iso-electric point of BSA, emulsion stabilized by BSA was quite unstable if ionic strength was below ca. 30 mM, but it became rather stable at higher ionic strength conditions. Surface tension for aqueous solutions of octylglucoside, sucrose laurate, glucose octanoate, and allose octanoate was measured as a function of concentration to get their critical micelle concentration and amount of surface excess.
3.Surface force curves between a polystyrene particle and a silica plate both immersed in cationic surfactant solutions were measured by using AFM apparatus. It was confirmed that the effect of repulsive electrical double layer force increased with surfactant concentration and there existed some kind of steric force originated from polymer molecules. Further, spectro-ellipsometry for spin-coat polystyrene thin film in aqueous solutions was performed to estimate the film thickness and water content in the film. In cationic surfactant solutions, the film thickness decreased which suggested coming off of polystyrene molecules from interface.
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Research Products
(3 results)
