2012 Fiscal Year Final Research Report
Integrated Analysis on Transport Phenomena during Thin Film Formation Using Inkjet method
| Project/Area Number |
22360324
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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 |
Properties in chemical engineering process/Transfer operation/Unit operation
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| Research Institution | Kyushu University |
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Principal Investigator |
FUKAI Jun 九州大学, 工学研究院, 教授 (20189905)
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| Co-Investigator(Renkei-kenkyūsha) |
NAKASO Kouichi 九州大学, 工学研究院, 助教 (40363379)
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| Project Period (FY) |
2010 – 2012
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| Keywords | 薄膜形成 / 乾燥工程 / 移動現象 / 自然対流 |
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| Research Abstract |
A way how to flatten a thin film using inkjet method is discussed experimentally and theoretically. Firstly the fluid dynamics in solution droplets evaporating on a substrate are analyzed. On the present system, the solutal-derived and thermal-derived Marangoni forces affect the fluid dynamics. They develop the flow in the opposite direction on the free surface. The thermal-derived forces increase with increasing the temperature of substrate. However, after evaporation is advanced in time, the solutal-derived forces finally dominates the fluid dynamics.The reason why binary solvent often forms a flat thin film has been thought to be that the fluid flow in the droplet can be controlled by the difference between the surface tensions of the solvents. However, the film configuration is not correlated to the fluid flow expected from the difference between the surface tension of the solvents, because the solutal-derived forces are larger than solvent-derived one.Consequently, the film shape is influenced by self-pinning position, which can be controlled by viscosity , contact angle and evaporation rate. The Marangoni forces are used to control delicate flatness. According to this result, a new method is proposed to form flat thin films.
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