Study of phase transition of ferroelectric polymers by use of molecular dynamics and x-ray diffraction
| Project/Area Number |
03455003
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
広領域
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| Research Institution | Hokkaido University of Education, Hakodate |
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Principal Investigator |
TAKAHASHI Nobuyuki Hokkaido University of Education, Hakodate, Associate Professor, 函館校, 助教授 (90163279)
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| Project Period (FY) |
1991 – 1992
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| Project Status |
Completed (Fiscal Year 1992)
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| Budget Amount *help |
¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1992: ¥800,000 (Direct Cost: ¥800,000)
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| Keywords | molecular dynamics simulation / structural phase transition / ferroelectric polymers / dipole orientation / electrostatic interaction / antiferroelectric phase / paraelectric phase / poly(vinylidene fluoride) / 分子動力学 / 結晶構造 / コンフォメ-ション / 双極子秩序 |
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| Research Abstract |
Molecular dynamics simulations of the ferroelectric phase (low temperature phase) and a hypothetical paraelectric phase (high temperature phase) of poly(vinylidene fluoride) (PVDF) have clarified the following results.
(1) Control of macroscopic electric fields is necessary for the simulation of the ferroelectric phase of PVDF. The effects of the electric fields suggest that the electrostatic interaction stabilizes the ferroelectric phase of poly(vinylidene fluoride).
(2) The ferroelectric phase is transformed into nonpolar structures in the medium without polarization. The transition between the nonpolar phase and the ferroelectric phase is observed at low temperatures and suggests a possibility of antiferroelectric phase.
(3) The simulation of a nonpolar phase at high temperature shows a characteristic rotation and inversion motion of dipoles and the sliding diffusion of the molecular chain, It shows a possibility of the paraelectric phase.
(4) A nonlinear lattice size dependence of the anisotropic stress is observed at a high temperature phase of PVDF. This phenomenon gives an explanation of the structural phase transition accompanied by the stretching of the chain length induced by the pressure.
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Report
(3 results)
Research Products
(16 results)
