The multi-lobed rotation of droplets induced by interfacial reactions

In this Letter, we report a novel phenomenon—that the multi-lobed rotation of a droplet can occur when controlling only its volume and without the use of external devices, which is quite different from previous studies. This phenomenon is based on the interfacial reaction causing the droplet rotation effect. In such a system, the angular velocity and lobe number show an inversely linear relationship with the droplet radius. By controlling the volume of a droplet, we can manipulate it to form four-, three-, and two-lobed shapes. Simple models are also proposed to explain this phenomenon. The results indicate that this phenomenon is consistent with the theory of Scriven and Brown.