Coalescence dynamics of ordered breath figures

Abstract

Breath figures are the characteristic droplet patterns which appear when one breathes onto a cold surface. Since the droplets are formed by nucleation, these patterns are usually disordered. In the present study we examine, for the first time, the growth of ordered breath figures which are generated by providing a substrate with a structured wettability. We are able to introduce disorder in a controlled manner and study its influence on the coalescence dynamics. The experimental results are compared with theoretical predictions based on geometrical considerations at which significant discrepancies were found. We conclude that the coalescence behavior of ordered breath figures is very sensitive to the microscopic dynamics taking place at the aqueous interfaces between the droplets.