Deformation dynamics of double emulsion droplet under shear

We combine experimental observations with numerical simulations to explore the deformation dynamics of double emulsion droplet under shear. Two types of transient deformation topologies are identified via the respective underlying physical mechanisms. Especially, we demonstrate that the inner droplet can enhance the retracting of integral droplet, which leads to more intense transient deformation oscillations of double emulsion droplet than those of single-phase one. We further provide a regime diagram to quantitatively recognize the respective regime of these two transient deformation topologies, depending on the capillary number and radius ratio of inner droplet to the outer one.