Bursting Drops

TL;DR

This paper uncovers the process of oil drop bursting at the water surface, revealing a jetting reversal that produces daughter droplets, with implications for environmental and industrial applications.

Contribution

It reports a novel jetting reversal during oil drop bursting, linking daughter droplet size to liquid properties and demonstrating methods to control this process.

Findings

Daughter droplet size correlates with bulk liquid properties.

Increasing viscosity or adding microparticles suppresses droplet formation.

Applications include colloidal synthesis, emulsions, and environmental studies.

Abstract

For decades, researchers worldwide have investigated phenomena related to natural, artificial oil leakages such as oil drop formation within water bodies, their rise, and oil slick evolution after they breach the water-air interface. Despite this, the event leading to slick formation -the bursting of oil drops at the liquid-air interface has remained unnoticed thus far. In this work, we investigate this and report a counterintuitive jetting reversal that releases a daughter oil droplet inside the bulk as opposed to the upwards shooting jets observed in bursting air bubbles. We show that the daughter droplet size thus produced can be correlated to the bulk liquid properties and that its formation can be suppressed by increasing the bulk viscosity or by the addition of microparticles. We further demonstrate the significance of our results by synthesizing colloidal pickered droplets and show applications of bursting compound drops in double emulsions and studies on raindrop impact on a slick. These results could be immensely transformative for diverse areas, including climatology, oceanic, atmospheric sciences, colloidal synthesis and drug delivery.