1997 Fiscal Year Final Research Report Summary
Investigation on the mechanism of crystallization and aggregation of small molecules in the polymer matrices
| Project/Area Number |
08640742
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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 | KYUSHU UNIVERSITY |
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Principal Investigator |
SASAKI Shigeo Kyushu of University, Faculty of Science, Department of chemistry, Research Associate, 理学部, 助手 (30225867)
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| Project Period (FY) |
1996 – 1997
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| Keywords | Polymer matrices / Gel / Hydrophobic counterion binding / Volume phase transition / Crystal growth / KNO_3 / CaCO_3 |
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| Research Abstract |
The followings have been revealed. 1) The aggregation of small molecules and the condensation of gel chains are highly coupled in the case that the former and the latter are strongly interacting with each other. 2) The aggregation patterns form in the gel in the aggregation processes. The volume change behvior and the volume phase transition of N-isopropylacrylamide (NIPA) are found to be well described by the ratio of the chemical potential to the thermal energy, which are functions of the temperature, the salt concentration, and the sugar concentration. From this fact, a new theory of mechano-chemical coupling for the volume phase transition of gel has been developed. 3) The Ostwald ripening of KNO_3 crystanllization in the acrylamide gel has been reconfirmed. It has been found that the crystals which ripen at one side and melt at the other side looK to move in the gel. 4) The CaCO_3 crystals are produced between two cellulose membranes that contact with the gels containing Na_2CO_3 and CaCl_2. The size of crystals increases with increase in the concentration of Na_2CO_3 and CaCl_2.5) The cooperativity of the hydrcphobic counterion (dodecylpyridinium ion) binding to ionic gels (gels of acrylate copolymer with methylacrylate, ethylacrylate, n-propylacrylate, or n-butylacrylate) reduces in strengthening the hydrophobicity of gel chains. The hydrophobic interaction between the bound counterions, which makes the binding cooperative, is shielded with the hydrophobic inteaction between the bound counterion and the chain.It has been also found that the hydrohobicity of chains promotes the Ca^<2+> binding to ionic groups of the chains. 6) The volume phase transition of the NIPA gel disappears in introducing the electric charges into the gel chain. This finding is inconsistent with the theory that the charge is necessary for the volume phase transition.
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