1997 Fiscal Year Final Research Report Summary
Preparation of Ultra Water-repellent Films with Transparency and Hardness by Plasma-enhanced CVD
| Project/Area Number |
08555171
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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 | 展開研究 |
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| Research Field |
Material processing/treatments
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| Research Institution | Nagoya University |
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Principal Investigator |
TAKAI Osamu Nagoya University, Department of Materials Processing Engineering, Professor, 工学研究科, 教授 (40110712)
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| Co-Investigator(Kenkyū-buntansha) |
HOZUMI Atsushi Toyoda Automatic Loom Works, Ltd., R&D ceneter, Researcher, 技術開発研究所, 研究員
INOUE Yasushi Nagoya University, Department of Materials Processing Engineering, Research Asso, 工学研究科, 助手 (10252264)
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| Project Period (FY) |
1996 – 1997
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| Keywords | water repellency / plasma-enhanced CVD / perfluoro-alkyl silanes / organosilicon compound / hard film / transparency / adhesion / low-temperature preparation |
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| Research Abstract |
Low temperature deposition of water-repellent thin films was carried out using various kinds of organosilicon compound by microwave plasma-enhanced chemical vapor deposition (MWPECVD) .
First, we used perfluoro-alkyl silanes (FASs) as raw materials and investigated the deposition of water-repellent films. The water repellency of the deposited films depended on the perfluoro-alkyl chain length. The maximum water-contact angle was about 107ﾟ which was similar to the angle for polytetrafluoro-ethylene(PTFE).
Second, we developed a multiple-step MWPECVD process. We controlled the gas composition and the amount of reactant supplied during deposition. In the first step of this process, a SiO_2 film was prepared using the mixture of tetramethylsilane (TMS) and oxygen. After deposition of the SiO_2 layr, we decreased the oxygen supply gradually and then started to introduce FAS with Ar to from a water-repellent layr. The hardness of the film increased with a decrease in deposition time of the wa
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ter-repellent layr. This process enabled the low-temperature deposition of SiO_2 films having both high hardness similar to boro-silicate glass and high water repellency. The films had also high transmittance in the visible range.
Third, ultra water-repellent thin films with a water-contact angle of over 150ﾟ were prepared by controlling the surface morphology. We used triple gas mixtures of TMS or hexamethyldisilane (HMDS), FAS and Ar as source gases. Surface roughness was controllable by changing the gas composition and the total pressure. The water-contact angle increased with surface roughness. We succeeded in the preparation of ultra-water repellent films with a water-contact angle of 160ﾟ by optimizing the preparation conditions.
Fourth, we studied the deposition parameters in the MWPECVD system to prepare a thin film with ultra water repellency and high transmittance. As a result of this study, we succeeded in the preparation of the film by using a triple gas mixture of TMS or trimethylmethoxysilane (TMMOS), FAS and Ar. We optimized deposition parameters such as the total pressure, the gas composition, the distance between the position of outlets of reactant gases and the substrate position, and the substrate temperature. Consequently, we prepared the films with a water-contact angle of over 140ﾟ and transmittance of over 80% in the visible range. Less
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