抄録
Droplet impact on a solid surface is essential phenomenon for industry applications such as semiconductor cleaning. We present experimental observation of droplet impact on a solid surface. Using the curvature of droplet surface as a lens to intensify the illumination, we can observe the development of lamella at early stage after the impact. We apply plasma treatment to change wettability of the solid surface. In case of high-speed droplet impact on non-plasma-treated surface, fingers are formed from the edge of lamella, and then splash is ejected at the tip of finger. On the other hand, lamella spreads with a circle shape and no finger and splash are observed when droplet collides with plasma-treated surface in high-speed impact.
