1990 Fiscal Year Final Research Report Summary
Research into Formation and Structure of Helical Superstructure formed from Synthetic Bilayer Membrane
| Project/Area Number |
01550687
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
高分子物性
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| Research Institution | Chiba University |
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Principal Investigator |
YAMADA Norihiro Chiba University, Faculty of education, Associate Professor, 教育学部, 助教授 (40182547)
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| Project Period (FY) |
1989 – 1990
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| Keywords | Synthetic Bilayer Membrane / Helical Superstructure / Amphiphile / Even-Odd-Chain Effect / Chirality / Fourier Transform Infrared Spectrum / Aggregation Morphology / Hydrogen Bond |
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| Research Abstract |
Bilayer aggregate which formed from amphiphilic compound in water sometimes transforms into helical superstructure by incubation at temperatures below the gel to liquid-crystal phase transition (Tc). We investigated the helical superstructure by using more than 20 amphiphiles to elucidate driving force of the helix-formation and molecular orientation or packing structure in the helices, and obtained following results.
1. Chiral, double-chain ammonium amphiphiles possessing shorter hydrophobic chain formed the helical superstructures in preference to those possessing longer hydrophobic chain; dodecyl > tridecyl > tetradecyl > pentadecyl > hexadecyl.
2. Although the formation of the helical aggregates were observed in aqueous solution of an achiral, single-chain ammonium amphiphile which contained a hydrogen bonding group, the helical superstructure was predominantly formed from chiral amphiphiles rather than achiral amphiphiles. The result means that the helix-formation is promoted by the presence of an asymmetric carbon and hydrogen bonding groups. And these structural moieties cooperatively act on the helix-formation.
3. Annealing was more effective to form the helical superstructure than incubation at a constant temperature below Tc.
4. Electronic and infrared spectra of the amphiphiles were not changed without respect to whether the amphiphiles formed large helices or fragmental helices. Thus the molecular orientation and packing is locally identical between large and small helices.
5. Electronic and infrared spectra of aqueous bilayer membranes were alternatively changed with number of carbon atoms in the hydrophobic chain, which was independent of the helix-formation. Therefore, it became apparent that the even-odd-chain effect was an general phenomenon in the bilayer systems.
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