2002 Fiscal Year Final Research Report Summary
Development of the in-situ measurement compound equipment of the power between the surfaces, and surface detailed structure
| Project/Area Number |
13450317
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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 |
化学工学一般
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
HIGASHTIANI Ko KYOTO UNIV., CHEM. ENG., PROFESSOR, 工学研究科, 教授 (10039133)
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| Co-Investigator(Kenkyū-buntansha) |
KANDA Yoichi CHEM. ENG., INSTRUCTOR, 工学研究科, 助手 (60243044)
MIYAHARA Minoru CHEM. ENG., ASSOC. PROFESSOR, 工学研究科, 助教授 (60200200)
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| Project Period (FY) |
2001 – 2002
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| Keywords | Atomic force microscope / Adsorbed layer / Polymer / Surface force / Adhesion force / Flocculants |
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| Research Abstract |
In situ observation for the investigation of the structure of adsorbed layer on mica plate in cationic polymer-electrolyte aqueous solution was carried out by using an atomic force microscope. Interaction forces between surfaces were also measured in the same way. Comparing with both results each other, following conclusions were obtained.
(1) It takes over 10 days until the enough relaxation of the cationic polymer-electrolyte molecules. We succeeded in-situ observation of single molecule whose molecular weight is 10 million in water, after keeping its dilute solution for 20 days.
(2) The shape of the adsorbed structure is like the island structure and its size increases with its molecular weight.
(3) Addition of inorganic electrolytes makes the adsorbed structure small because of the decrease of the electrostatic repulsive force and the suppression of polymer relaxation.
(4) Block-like adsorbed structure invites larger and longer-range attractive force and has higher flocculate effect th
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an the chain like. This suggests that the powder-style polymer flocculants should be employed to the flocculation process at the time before its sufficient relaxation occurs.
Similar investigations for amphoteric polymer electrolytes were carried out and following conclusions were obtained.
(1) At the neutral pH, in which the amphoteric polymer molecules become neutral, their adsorbed structure is block like. In the lower pH range, polymer molecules adsorb like chains, because their positive charges become predominant.
(2) The thickness of the adsorbed layer of the polymer molecules increases with pH. According to adhesion results, the solution pH does not influence to the flocculation.
The effect of poly-aluminum chloride which is often used for real processes was investigated and the following were concluded.
(3) Very small block-like polymer adsorbs with high density on the surface modified by poly-aluminum chloride.
(4) Strong attractive force will act between these surfaces. This is expressed as the electrostatic force, which is attributed that multi-valence cations localized on the negative charge surface and big electrostatic attractive force appears. Less
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