Elimination of wetting study flaws in unsaturated vapors based on Laplace fit parameters

Abstract

Performing digital video image processing of sessile droplets and Laplace fit optimization is one of the most widely used modern techniques to measure the contact angle. The attractive feature of this approach is related to the possibility of simultaneous determination of numerous droplet parameters, such as contact angles, droplet surface tension, droplet surface area and droplet volume. However, lately in the literature, the analysis of the droplet shape is usually restricted by the contact angle determination, and the experiments are performed under open atmospheric conditions without simultaneous monitoring of the other droplet parameters. In this brief note, it is shown how wettability measurements under conditions of undersaturated water vapor affect the observed water droplet parameters.