2001 Fiscal Year Final Research Report Summary
Membrane design for removal of environmental pollutant from waste water by plasma graft
| Project/Area Number |
11650794
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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 |
反応・分離工学
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| Research Institution | The University of Tokyo |
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Principal Investigator |
YAMAGUCHI Takao Graduate School Of Engineering, The University of Tokyo, Assistant Professor, 大学院・工学系研究科, 講師 (30272363)
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| Co-Investigator(Kenkyū-buntansha) |
TAKABA hiromitu Graduate School Of Engineering, The University of Tokyo, Redearch Assistant, 大学院・工学系研究科, 助手 (80302769)
NAKAO shin-ichi Graduate School Of Engineering, The University of Tokyo, Profrssor, 大学院・工学系研究科, 教授 (00155665)
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| Project Period (FY) |
1999 – 2000
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| Keywords | Plasma-graft polymerization / Bio mimetic membranes / Water treatment / Stimuli responsive gel / Host-guest / Crown ether / Stimuli responsive materials / Gate membranes |
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| Research Abstract |
We have fabricated a molecular recognition ion gating membrane. This synthetic membrane spontaneously opens and closes its pores in response to specific solvated ions. In addition to this switching function, we found that this membrane could control its pore size in response to a known concentration of a specific ion. The membrane was prepared by plasma graft copolymerization, which filled the pores of porous polyethylene film with a copolymer of NIPAM (N-isopropylacrylamide) and BCAm (benzo[18]crown-6-acrylamide). NIPAM is well known to have an LCST (lower critical solution temperature), at which its volume changes dramatically in water. The crown receptor of the BCAm traps a specific ion, and causes a shift in the LCST. Therefore, selectively responding to either K^+ or Ba^<2+>, the grafted copolymer swelled and shrank in the pores at a constant temperature between two LCSTs. The solution flux in the absence of Ba^<2+> decreased by about two orders of magnitude over a solution flux containing Ba^<2+>. The pore size was estimated by the filtration of aqueous dextran solutions with various solute sizes. This revealed that the membrane changed its pore size between 5 and 27 nm in response to the Ba^<2+> concentration changes. No such change was observed for Ca^<2+> solutions. Furthermore, this pore size change occurred uniformly in all pores, as a clear cut-off value for a solute size that could pass through pores was always present. This membrane may be useful not only as a molecular recognition ion gate, but also as a device for spontaneously controlling the permeation flux and solute size. Also, we can design the molecular recognition gating membrane from information about number and logK of receptors and * H and LCST of grafted polymer, and we can measure these material characteristics easily. When we wish to prepare a membrane of a new receptor or change response conditions, we don't need to prepare membranes by try and error.
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