The yoga of droplets: coalescence in complex fluids

Abstract

Coalescence of liquid drops is a widely observed phenomenon across a diverse range of natural and industrial processes, ranging from the formation of raindrops and the growth of tumor cells to inkjet printing. The physics involved in this seemingly simple process of coalescence is far from simple, and the rheological complexity of the fluid under investigation makes the problem even more challenging. The present article provides a brief overview of existing knowledge on this topic and discusses the potential avenues for future research. Special attention is given to non-Newtonian fluids and soft materials, which exhibit distinct behaviors compared to Newtonian liquids, revealing fascinating deviations that demand deeper investigation.