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

Paper SS-ThP26
Deformation and Motion of a Droplet of Water-based Magnetic Fluid on a Hydrophobic Surface by Gravity and Magnetic Field

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

Session: Surface Science Poster Session
Presenter: A. Nakajima, KAST (Kanagawa Academy of Science and Technology) and Tokyo Institute of Technology, Japan
Authors: A. Nakajima, KAST (Kanagawa Academy of Science and Technology) and Tokyo Institute of Technology, Japan
H. Asakura, KAST and Tokyo Institute of Technology, Japan
M. Sakai, KAST, Japan
A. Hashimoto, KAST, Japan
S. Suzuki, KAST and Tokyo Institute of Technology, Japan
Y. Kameshima, KAST and Tokyo Institute of Technology, Japan
N. Yoshida, KAST and CCR, Tokyo University, Japan
K. Okada, Tokyo Institute of Technology, Japan
Correspondent: Click to Email
Control of a liquid droplet on a solid surface has attracted much attention as an indispensable technology for various industrial items, especially for hydrophobic coatings. Recently, not only for water-repellent treatment, this technology has become important for microscale chemical processing systems. To date, various investigations have been carried out to examine the motion of a liquid droplet on a solid surface using external fields. However, investigations on the control of a solid and liquid mixture using an external field are limited. Magnetic fluid is a very common solid-liquid mixture, In the current paper, motion and deformation of a water-based magnetic fluid on a hydrophobic surface were investigated under gravity and a magnetic field. Surface energy and the resultant contact angle of magnetic fluid depend on the surfactant concentration. Viscosity of the fluid is mainly governed by magnetite concentration. The front edge of the droplet moved under a weak external field. The rear edge required a higher external field for movement. The force for moving of the front edge is almost identical between gravity and the magnetic field. However, that of the rear edge is different. The motion of magnetic fluid by an external field depends on the concentrations of surfactant and magnetic particles, external field, and experimental assembly.