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Processing of hard super-hydrophobic film with TiO_2 photocatalyst, and mechanisms responsible for self-cleaning performance

Research Project

Project/Area Number 12555241
Research Category

Grant-in-Aid for Scientific Research (B)

Allocation TypeSingle-year Grants
Section展開研究
Research Field 工業物理化学
Research InstitutionThe University of Tokyo

Principal Investigator

HASHIMOTO Kazuhito  Research Center for Advanced Science and Technology, Professor, 先端科学技術研究センター, 教授 (00172859)

Co-Investigator(Kenkyū-buntansha) NAKAJIMA Akira  Advanced Systems of Technology Incubation LTD., Research Manager, 取締役研究所長(研究職) (00302795)
Project Period (FY) 2000 – 2001
Project Status Completed (Fiscal Year 2001)
Budget Amount *help
¥12,800,000 (Direct Cost: ¥12,800,000)
Fiscal Year 2001: ¥4,200,000 (Direct Cost: ¥4,200,000)
Fiscal Year 2000: ¥8,600,000 (Direct Cost: ¥8,600,000)
KeywordsTitanium Dioxide / Super-hydrophobic / carbon black / contact angle / ゾルゲル / 分相 / コロイダルシリカ
Research Abstract

Super-hydrophobic surfaces require appropriate surface roughness with surfaces having low surface energy. However, surfaces with a high roughness commonly show lower hardness than flat surfaces, and this is a crucial problem for the application of super-hydrophobic surfaces. We have prepared a hard super-hydrphobic silica film with visible light transmission by combining two different roughness dimensions. We combined a crater-like roughness (〜800nm) prepared by a phase separation of sol-gel method, and a fine roughness (〜20nm) provided by colloidal silica. Photocatalyst can be combined to this film by utilizing TiO_2 sol. Processing temperature has been lowered to 250℃ by utilizing the coagulation of colloidal silica. The concept of roughness combination is important for the design of super-hydrophobic films with high durability.
It has been known that TiO_2 photocatalyst effectively provides a self-cleaning property to super-hydrophobic films and maintains high contact angles during long periods of outdoor exposure. We have investigated the mechanism that might be responsible for the overall self-cleaning performance. Based on the experimental results, it was confirmed that at least following two mechanisms are responsible : 1) a long diffusion distance of the radical species on the fluorine-coated surface ; and 2) reduction of static electricity by the photo-induced hydrophilicity of TiO_2.

Report

(3 results)
  • 2001 Annual Research Report   Final Research Report Summary
  • 2000 Annual Research Report
  • Research Products

    (14 results)

All Other

All Publications (14 results)

  • [Publications] A.Nakajima, Z.Yoshimitsu, K.Hashimoto, T.Watanabe et al.: "Processing of a Super-Hydrophobic Silica Film by Combining Two Different Roughness Dimensions"Ceramic Processing Science IV. 112. 323-328 (2001)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2001 Final Research Report Summary
  • [Publications] A.Nakajima, C.Saiki, K.Hashimoto, T.Watanabe et al.: "Processing of roughened silica film by coagulated colloidal silica for super-hydrophobic coating"J. Mater. Sci. Lett.. 20,21. 1975-1977 (2001)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2001 Final Research Report Summary
  • [Publications] 中島章(分担執筆): "最新光触媒と実用化戦略(第5章)"(株)ビー・ケイ・シー(印刷中). (2002)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2001 Final Research Report Summary
  • [Publications] A. Nakajima, C. Saiki, K. Hashimoto and T. Watanabe: "Processing of Roughened Silica Film by Coagulated Colloidal Silica for Super-Hydrophobic Coating"J. Mater. Sci. Lett.. 20,21. 1975-1977 (2001)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2001 Final Research Report Summary
  • [Publications] A. Nakajima (Share Writing): "Recent Photocatalysis and its strategy for real application"BKC. in press. (2002)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2001 Final Research Report Summary
  • [Publications] A. Nakajima, Z. Yoshimitsu, C. Saiki, K. Hashimoto, and T. Watanabe , edited by S. Hirano, G. L. Messing, and N. Claussen: "Processing of a Super-Hydrophobic Silica Film by Combining Two Different Roughness Dimensions , Ceramic Processing Science IV, Ceramic Transactions"American Ceramic Society, Westerville. 112 (2001)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2001 Final Research Report Summary
  • [Publications] A.Nakajima, Z.Yoshimitsu, C.Saiki, K.Hashimoto, T.Watanabe: "Processing of a Super-Hydrophobic Silica Film by Combining Two Different Roughnesses"Ceramic Processing Science VI. 323-328 (2001)

    • Related Report
      2001 Annual Research Report
  • [Publications] A.Nakajima, S.Koizumi, T.Watanabe, K.Hashimoto: "Effect of Repeated Photo-Illumination on the Wettability conversion of Titanium Dioxide"J. Photochemistry and Photobiology A : chemistry. 146. 129-132 (2001)

    • Related Report
      2001 Annual Research Report
  • [Publications] A.Nakajima, C.Saiki, K.Hashimoto, T.Watanabe: "Processing of Roughed Silica Film by Coagulated Colloidal Silica for Super-hydrophobic Coating"J. Materials Science Letters. 20. 1975-1977 (2001)

    • Related Report
      2001 Annual Research Report
  • [Publications] K.Takeda, A.Nakajima, Y.Murata, K.Hashimoto, T.Watanabe: "Control of Water Droplets on Super-Hydrophobic Surfaces by Static Electric Field"Jpn. J. Appl. Phys.. 41. 287-291 (2002)

    • Related Report
      2001 Annual Research Report
  • [Publications] A.Nakajima,K.Abe,K.Hashimoto,T.Watanabe: ""Preparation of Hard Super-Hydrophobic Films with Visible Light Transmission""Thin Solid Films. 376. 140-143 (2000)

    • Related Report
      2000 Annual Research Report
  • [Publications] A.Nakajima,K.Takai,K.Hashimoto,T.Watanabe: ""Transparent Superhydrophobic Thin Films with Self-Cleaning Properties""Langmuir. 16(17). 7044-7047 (2000)

    • Related Report
      2000 Annual Research Report
  • [Publications] A.Nakajima,S.Koizumi,T.Watanabe,K.Hashimoto: ""Photoinduced Amphiphilic Surface on Polycrystalline Anatase TiO_2 Thin Films""Langmuir. 16(17). 7048-7050 (2000)

    • Related Report
      2000 Annual Research Report
  • [Publications] A.Nakajima,K.Hashimoto,T.Watanabe: ""Recent Studies on Super-Hydrophobic Films""Monatshiefte fur Chemie. 132. 31-41 (2001)

    • Related Report
      2000 Annual Research Report

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Published: 2000-04-01   Modified: 2016-04-21  

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