Divide yourselves! An interfacial reaction drives the spontaneous and sequential division of macroscopic droplets all the way into nanoscopic emulsions (see picture). The sizes of the divided droplets depend on the pH of the solution and the division process is governed by the interplay between surface tension and electrostatic effects. When the dividing droplets contain nanoscopic cargo (e.g., nanorods), they partition it equally into progeny micelles.