Direct observation of micro-droplet dynamics on substrates

Abstract

We developed a method to observe the dynamic behavior - such as impingement, wetting and penetration - of micro-droplets on substrates, with a time resolution higher than 1 μs. A combination of stroboscopic observation and a mechanism that provides a new landing position of solid substrate successfully enabled visual observation in a wide time range from 0.1 μs to longer than 1 ms. We observed the dynamic behavior of the droplets on permeable and impermeable solid substrates and examined their behaviors in very early time stages, in terms of the conventional physical theory of wetting and penetration.