For decades, two main facets of underwater oil spills have been explored extensively-the rise of oil drops and resulting evolution of the oil slick at the air-water interface. We report on the bursting of rising oil drops at an air-liquid interface which precedes slick formation and reveal a counterintuitive bulge reversal that releases a daughter oil droplet inside the bulk as opposed to upward-shooting jets observed in bursting air bubbles. By unraveling the underlying physics we show that daughter droplet size and bulk liquid properties are correlated and their formation can be suppressed by an increase in the bulk viscosity.
View Article and Find Full Text PDFWe investigate the arrested spreading of room temperature droplets impacting flat ice. The use of an icy substrate eliminates the nucleation energy barrier, such that a freeze front can initiate as soon as the droplet's temperature cools down to 0 °C. We employ scaling analysis to rationalize distinct regimes of arrested hydrodynamics.
View Article and Find Full Text PDFMetal-based antiperspirants have been in use for centuries; however, there is an increasing consumer demand for a metal-free alternative that works effectively. Here, we develop an artificial sweat duct rig and demonstrate an alternative, metal-free approach to antiperspiration. Instead of clogging sweat ducts with metal salts, we use a hygroscopic material to induce the evaporation of sweat as it approaches the outlet (i.
View Article and Find Full Text PDFHypothesis: Oil spills have posed a serious threat to our marine and ecological environment in recent times. Containment of spills proliferating via small drops merging with oceans/seas is especially difficult since their mitigation is closely linked to the coalescence dependent spreading. This inter-connectivity and its dependence on the physical properties of the drop has not been explored until now.
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