1998 Fiscal Year Final Research Report Summary
Study on the Molecular Motion in Organic Thin Film using Spin Probe Method and Molecular Dynamics
| Project/Area Number |
08650971
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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 |
工業物理化学
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
SUGA Kosaku Tokyo Institute of Technology, Faculty of Bioscience and Biotechnology, Research Associate (90016642)
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| Co-Investigator(Kenkyū-buntansha) |
SAKURAI Minoru Tokyo Institute of Technology, Associate Professor (50162342)
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| Project Period (FY) |
1996 – 1998
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| Keywords | spin probe method / doxyl stearic acid / molecular dynamics / spectral simulation |
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| Research Abstract |
(1). Elucidation of orientation and molecular motion of amphiphilic molecules in LB films by spin probe method.
Electron spin resonance spectra for the Langmuir-Blodgett (LB) films of 5-, 10-, and 16-doxylstearic acids (DXSTAs) and their mixtures with stearic acid (STA) complexed with polyallyl-amine were measured at various angles between the applied magnetic field and the film normal at various temperatures, From the angle dependence at the liquid nitrogen temperature where molecular motion can be neglected, accurate molecular orientation and its distribution were determined. From the temperature dependence, it was shown that end part of methylene chain did molecular motion, while the orientation regularity is kept in these LB films.
(2). Elucidation of orientation and molecular motion of amphiphilic molecules in cast films by spin probe method.
The spin probe method was applied to cast films of the tetraalkylammonium chloride with two long methylene chains. From the angular variation a
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nd the temperature dependence of the ESR spectra, it was shown that the isotropic motion was carried out by the tail part of methylene chain, while the motion of the methylene chain kept the orientation in the vicinity of the headgroup in these cast films.
(3). Control of phase separation condition of mixed LB films containing probe molecules.
It was found that in mixed LB films containing doxylstearic acid and perfluorodecanoic acid phase separation did not occur when the position of doxyl unit is closer to head group. Since the molecular occupation area of the probe molecule in monomolecular film on water surface increases due to the steric hinderance as the probe position approaches to the hydrophilic group, it was suggested that that decrease in the in-plane cohesion force between probe molecules was a main cause for the phase separation characteristics of such probe molecule.
(4). Simulation of the molecular motion in organic thin films using molecular dynamics method
The calculation program of such system by the molecular dynamics method which had advanced the improvement until now reached the level which can be almost used for actual research. As the result, it is expected that detailed information can be obtained on the molecular motion in these organic thin films from the ESR spectra of LB films containing spin probe molecules and their analysis with this program. Less
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