Control of Interface and Polarization in Ultra Thin Film of Ferroelectric Polymer
| Project/Area Number |
16350129
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Polymer/Textile materials
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| Research Institution | Tokyo University of Science |
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Principal Investigator |
FURUKAWA Takeo Tokyo University of Science, Department of Chemistry, Professor (90087411)
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| Co-Investigator(Kenkyū-buntansha) |
TAKAHASHI Yoshiyuki Tokyo University of Science, Department of Chemistry, Assistant Professor (80266923)
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| Project Period (FY) |
2004 – 2006
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| Project Status |
Completed (Fiscal Year 2007)
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| Budget Amount *help |
¥15,500,000 (Direct Cost: ¥15,500,000)
Fiscal Year 2006: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 2005: ¥5,700,000 (Direct Cost: ¥5,700,000)
Fiscal Year 2004: ¥8,300,000 (Direct Cost: ¥8,300,000)
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| Keywords | vinylidene fluoride / ferroelectrics / thin film / thickness / crystallization / kinetics / diffusion control / 強誘電性高分子 / 原子間力顕微鏡 / 表面 / 構造制御 / 微細加工 / 分極反転 / 超薄膜 / 界面 |
|---|
| Research Abstract |
We studied physical properties of thin films of VDF/TrFE copolymers. In thin films, electrode metal affects the properties. We studied the asymmetric properties such as D-E hysteresis and switching characteristics in thin films with different metals as electrodes of each side. The thickness dependence of the asymmetry shows that the difference of work functions between two metals is the origin of the asymmetry.
We also studied the thickness dependence of electric properties such as dielectric spectra and ferroelectric properties. The thickness dependence can be explained by the existence of electrically inactive layer at the interface.
The structural control of thin film is of great importance. We studied the morphology and kinetics of crystallization in thin films. The films were formed by spin-coating. The structure of thin films depends strongly on the treatment after spin-coating. Small grain-like structure appears in annealed samples and the size increases with annealing temperature
… More
up to the melting temperature. However, once the sample was melted and then cooled to re-crystallize, network structure of needle-like crystals appears. In order to study the formation mechanism of such structure, we conducted isothermal crystallization experiment. We found two kinds of morphology formed in thin film after isothermal crystallization: plate-like crystals and needle-like crystals. The size of crystals grown at a certain temperature for a certain time was measured and plotted against the crystallization time. It depends linearly on time and thus we can estimate the crystallization rate. Both crystals have the same crystallization rate. Thus, both have the same crystallization elementary process at the growth front. Therefore they are assigned as flat-on and edge-on lamella, respectively. In ultra-thin films, the plate-like crystals show fingering structure. By assuming that the fingering occurs due to the restricted diffusion of molecular chains along the surface, we estimated the diffusion coefficient. Less
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Report
(4 results)
Research Products
(12 results)
