On June 10, the article “Daughter bubble cascades produced by folding of ruptured thin films” appeared in Nature. A PhD student within the PCF group, Riëlle de Ruiter, contributed to this research during her MSc internship in the group of Howard Stone at Harvard University. In the article it is shown that for a large range of fluid parameters, interfacial bubbles can create numerous small bubbles when they rupture, rather than vanishing. It is demonstrated, both experimentally and numerically, that the curved film of the ruptured bubble can fold and entrap air as it retracts. The resulting toroidal geometry of the trapped air is unstable, leading to the creation of a ring of smaller bubbles. The higher pressure associated with the higher curvature of the smaller bubbles increases the absorption of gas into the liquid, and increases the efficiency of rupture-induced aerosol dispersal.
Figure 1 | (a-b) When a single soap bubble ruptures on a rigid surface, a ring of many daughter bubbles can form. (c-d) Similarly, when one of the daughter bubbles pops, even smaller bubbles are created, demonstrating a bubble-bursting cascade.
Reference: Daughter bubble cascades produced by folding of ruptured thin films, J. C. Bird, R. de Ruiter, L. Courbin, H. A. Stone, Nature 465, 759-762 (2010) [link]