| AVS 54th International Symposium | |
| Surface Science | Thursday Sessions |
| Session SS-ThP |
| Session: | Surface Science Poster Session |
| Presenter: | A. Nakajima, Tokyo Institute of Technology, Japan |
| Authors: | A. Nakajima, Tokyo Institute of Technology, Japan S. Suzuki, Tokyo Institute of Technology, Japan M. Sakai, Kanagawa Academy of Science and Technology, Japan A. Hashimoto, Kanagawa Academy of Science and Technology, Japan N. Yoshida, The University of Tokyo, Japan Y. Kameshima, Tokyo Institute of Technology, Japan K. Okada, Tokyo Institute of Technology, Japan |
| Correspondent: | Click to Email |
Self-assembled monolayer (SAM) coatings of organosilanes have been widely used for surface modification of inorganic materials. We studied the sliding behavior of water droplets sandwiched between Si substrates treated by octadecyltrimethoxysilane (ODS) and fluoroalkylsilane (FAS) by changing the plates' distance (D) and droplet mass (m). The sliding angle depended on D, m, and the upper and bottom combination of the coating. The droplet between FAS coatings exhibited larger sliding angle than the ODS coating when D=1.0 mm although the FAS coating possesses higher water contact angle. The sliding behavior of water droplets sandwiched between ODS and FAS coatings was observed using a high speed camera system on a declined surface (35 degrees). The larger droplet mass and plate distance, the larger sliding acceleration. The internal fluidity in the droplet visualized by particle image velocimetry method revealed that the droplet slid down with twin flows between plates and that their border was almost the center of the plates. The water droplet sandwiched between FAS/ODS exhibited heterogeneous rolling fluid: the border of the twin flow was not the center between the plates. The magnitude of the rolling fluid depended on the surface chemical composition and the distance between two plates.