How much force is needed to detach a tiny droplet from a surface? Remarkably, this fundamental question has no simple answer, even though it is relevant in numerous natural and applied contexts, e.g., fog harvesting and designing windshields and fabrics. We answer this long-standing question via comprehensive laboratory and computational experiments. The results demonstrate that the Young–Laplace equation can accurately predict the droplet detachment force. When challenged against experiments with liquids of varying properties and droplet sizes, the predictions are in excellent quantitative agreement, detaching from smooth and microtextured surfaces of wetting and non-wetting chemical make-ups.
Subkhi is a postdoctoral fellow at WDRC, King Abdullah University of Science and Technology. He obtained his Ph.D. in Physics from Durham University, UK. His research interests focus on wetting and interfacial phenomena. At KAUST, he employs experimental, computational, and theoretical approaches to study the physics of solid-liquid interfaces. In particular, he is interested in the applications of wetting phenomena, including liquid-repellent surfaces, oil-water separation, fog-harvesting surfaces, and capillary adhesion.