High-speed side-shooter using Leidenfrost phenomena

Abstract

Liquid delivery systems are important in microfluidic applications. In this paper, we report a high-speed side-shooter using a simple plate-like hot protrusion placed on the lower edge of a hot slope. In particular, we experimentally show that the side-shooter launches a droplet with a high speed (∼15cm/s). We propose a simple model to explain the side-shooting phenomenon; i.e., the hot protrusion causes an increase in the surface energy due to the formation of a new folded surface, which results from a new Leidenfrost phenomenon coupled with the protrusion, and therefore, the droplet can be launched at a high speed on the hot slope with a low friction due to the ordinary Leidenfrost phenomenon. A comparison of the theoretical results with the experimental results shows that they are in good agreement with each other. We believe that our side-shooter will play an important role in microfluidics in the future.