2006 Fiscal Year Final Research Report Summary
MECHANISM OF THE FILM FORMATION BY THE INKJET PRINTING METHOD
| Project/Area Number |
16360387
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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 UNIVERCITY |
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Principal Investigator |
FUKAI Jun Kyushu University, Faculty of Engineering, Professor, 工学研究院, 教授 (20189905)
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| Co-Investigator(Kenkyū-buntansha) |
TAKAHARA Atushi Kyushu University, Institute for Materials Chemistry and Engineering, Professor, 先導物質化学研究所, 教授 (20163305)
YAMAMOTO Tsuyoshi Kyushu University, Faculty of Engineering, Associate Professor, 工学研究院, 助教授 (20321979)
KANEDA Masayuki Kyushu University, Faculty of Engineering, Research Associate, 工学研究院, 助手 (50346855)
NAKASO Koichi Kyushu University, Faculty of Engineering, Research Associate, 工学研究院, 助手 (40363379)
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| Project Period (FY) |
2004 – 2006
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| Keywords | Inkjet Printing Method / Polymer Solution Droplet / Film Formation / Surface Wettability / Natural Convection / Flow Visualization / Site Selectivity |
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| Research Abstract |
For the inkjet printings of the polymer solution droplet (d= 30-100 μm), the effects of the physical properties of the solvent, the initial solute concentration and the surface wettability are studied. The evaporation process of the droplet is observed and the resulted film shape is measured.
1. Deposited on the lyophobic surface, ring-like films form at the high initial solute concentration and the high evaporation rate. This is due to the internal flow after the pinning of the contact line. The internal flow depends on the viscosity which decreases at the fast pinning.
2. On the lyophilic surface, dot-like films form at the high initial solute concentration. The binary solvent with the different boiling points is the breakthrough to control the film shape for the inkjet printings.
3. The binary-solvent inkjet printings increase the droplet viscosity at the pinning, which is the primary factor that the binary solvent affects the film shape.
4. The circulating source flow at the cross section of the droplet is observed by the flow visualization. This flow cannot be understood by the Marangoni convection due to the temperature difference on the surface.
5. The numerical simulation clarified that visualized flow is due to the natural convection by the density difference between the surface and the bulk of the droplet. This density difference is due to the solute concentration.
6. The strong convection is observed for the high initial solute concentration. This conflicts the high viscosity at the high solute concentration. This unexpected phenomenon is also understood by the natural convection due to the solute concentration.
7. The droplet ejected on the lyophobic/lyophilic patterned surface deposits on the lyophilic part. To delay the pinning time on the lyophilic part is found to be important to deposit on the lyophilic part.
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