AVS 53rd International Symposium
    Surface Science Thursday Sessions
       Session SS-ThP

Paper SS-ThP24
Motion of Water Droplets on Inclined Hydrophobic Surfaces in Flowing Air

Thursday, November 16, 2006, 5:30 pm, Room 3rd Floor Lobby

Session: Surface Science Poster Session
Presenter: A. Hashimoto, Kanagawa Academy of Science and Technology, Japan
Authors: A. Hashimoto, Kanagawa Academy of Science and Technology, Japan
J.-H. Song, Kanagawa Academy of Science and Technology, Japan
M. Sakai, Kanagawa Academy of Science and Technology, Japan
S. Suzuki, Kanagawa Academy of Science and Technology, and Tokyo Institute of Technology, Japan
N. Yoshida, Kanagawa Academy of Science and Technology, and The University of Tokyo, Japan
Y. Kameshima, Kanagawa Academy of Science and Technology, and Tokyo Institute of Technology, Japan
A. Nakajima, Kanagawa Academy of Science and Technology, and Tokyo Institute of Technology, Japan
Correspondent: Click to Email
Recently, not only for water-repellent treatment, control of liquid droplets on solid surfaces has become important for advanced device systems such as MEMS or microscale chemical processing. So far, various investigations have been performed to examine the motion of a liquid droplet on a solid surface using external fields such as gravity, electric fields, photo-illumination and a heat gradient. However, investigation on the control of a liquid droplet using air flow is insufficient although it is indispensable for the design of industrial items such as windshield of automobiles. In the present study, we investigated effect of air flow on droplet shape and motion on hydrophobic surfaces using high-speed cameras. Three silanes were deposited on Si substrates by CVD method. Water droplets with different weight (10 ~ 50 mg) were placed on the surfaces, which were tilted at 0, 35, 45 and 60 ° in an open-circuit-type wind tunnel. We carefully observed the droplets by high-speed cameras changing a wind velocity (0 ~ 20 m/s). The droplet motion on inclined hydrophobic surfaces in air flow was classified into three categories by the competition between the forces of the wind and the gravity; sliding down, stopping and climbing up. Detailed relationship among these behavior, moving speed, droplet deformation, experimental condition and surface state will be discussed.