Comment on “Millimeter-Sized Hole Damming”

Abstract

In a recent article, Ng and co-workers (Langmuir 2017, 33, 13892-13898; doi: 10.1021/acs.langmuir.7b03290) demonstrated the ability of containers with a small hole in their bottom to resist the drainage of water. They used Laplace's capillary rise equation to explain their results, which grossly underestimated the onset of drainage. In this comment, an alternative analysis is offered. Equations are derived specifically for the drainage of liquid from a small hole in a horizontal surface. This approach yielded reasonably accurate predictions for Ng's experimental data.