1996 Fiscal Year Final Research Report Summary
Dynamic Structure Factor for Lipid Membranes with Phase Transition
| Project/Area Number |
06640505
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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 |
物性一般(含基礎論)
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| Research Institution | HIROSHIMA UNIVERSITY |
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Principal Investigator |
TAKEDA Takayoshi Hiroshima University, Faculty of Integrated Arts and Sciences, Associate Professor, 総合科学部, 助教授 (70034593)
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| Co-Investigator(Kenkyū-buntansha) |
SETO Hideki Hiroshima University, Faculty of Integrated Arts and Sciences, Research Associat, 総合科学部, 助手 (60216546)
KOMURA Shigehiro Hiroshima University, Faculty of Integrated Arts and Sciences, Professor, 総合科学部, 教授 (50034583)
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| Project Period (FY) |
1994 – 1996
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| Keywords | neutron spin echo / membrane / dynamic structure factor / amphiphiles / phase transition / slow dynamics / small angle scattering / lipid |
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| Research Abstract |
We have constructed and have been improving a neutron spin echo spectrometer (NSE) at C_<2-2> port of JRR-3M,JAERI in order to study dynamical behaviors of large assemblies made of medium-sized molecules or assemblies of large molecules and also to dynamical critical behavior of condensed matters. The performance of our NSE spectrometer was comparable to that of MESS at LLB in Saclay, France. In order to further gain neutron intensity, we have been installing a detector system with an assembly of position sensitive detectors.
Neutron spin echo and small angle neutron scattering (SANS) studies have been performed to investigate the slow dynamics such as membrane undulation and the structural phase transition in the dipalmitoylphosphatidylcholine (DPPC) -water-salt, C_<12>E_5/n-octane/water and AOT/n-decane/water systems. The mean curvatures and microscopic interactions of the interfacial membranes were estimated using the cross partial structure functions obtained from our SANS experiments. Dynamic structure factor I (Q,t) obtained from our NSE experiments were well fitted to the equation I (Q,t) =exp [(-GAMMAt)^<2/3>] in the DPPC-water-CaCl_2 system and also in the bicontinuous microemulsion phases and the lamella phase of the C_<12>E_5/n-octane/water system. The relaxation rateGAMMA increased as Q^3. A recent theory of Zilman and Granek, where they use the Helfrich bending free energy to describe membrane undulations in sponge and lamellar phases, was first supported by our NSE experiments. We estimated bending modulus of the membranes using their theory.
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