AVS 56th International Symposium & Exhibition
    Advanced Surface Engineering Tuesday Sessions
       Session SE-TuM

Paper SE-TuM6
Development of Water Repellent Metal Oxide Thin Film as Like Organic Polymer

Tuesday, November 10, 2009, 9:40 am, Room C4

Session: Hard and Nanocomposite Coatings
Presenter: T. Watanabe, The University of Tokyo, Japan
Authors: T. Watanabe, The University of Tokyo, Japan
Y. Yokota, The University of Tokyo, Japan
N. Yoshida, The University of Tokyo, Japan
Y. Okura, Kogakuin University, Japan
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Mechanically durable water repellent thin film composed of only metal oxides such like Al2O3, HfO2, ZrO2, TiO2 and CeO2 were successfully developed by sol-gel process. The key points to enhance dynamic hydrophobicity are reducing surface roughness and increasing chemical homogeneity. Surprisingly to say, developed films show 100 degree of water contact angle and sliding angles of water droplet is only around 20 degree. Water repellency has not been deteriorated even by 500 times abrasion tests of 0.1kg/cm2. Water removability on these films is as like that of hydrophobic polymer surface. Fundamentally, intrinsic surface wettability of metal oxide is hydrophilic. However nanometer scale flatness and homogenous surface reduce activation energy of de-wetting process of water droplet. It is considered to cause of higher water removability. Durable hydrophobic surface composed only by inorganic oxide attracts much attention because it can be applied for water repellent automobile glass window and other applications which need higher mechanical strength and durability. Moreover, developed films show several unique properties which cannot be observed on organic polymer surfaces.