Radial Marangoni instability in an evaporating sessile droplet —

Evaporation of a picolitre droplet of ethanol and water with suspended particles that track Marangoni driven flows. A radial instability in the flow leads to the appearance of a propeller before the droplet finishes drying in just over a second. +50% contrast.

https://downloads.sms.cam.ac.uk/2877179/2877186.mp4