Deformation, Orientation and Bursting of Microcapsules in Simple Shear Flow: Wrinkling Processes, Tumbling and Swinging Motions

In a series of experiments we systematically investigated the orientation and deformation behavior of non-spherical capsules in simple shear flow. We observed a continuous capsule rotation at low shear rates, denoted as tumbling mode. A swinging mode at elevated shear rates was characterized by oscillations of the inclination angle around positive values, superimposed by a tank-treading motion of the capsule membrane. The transition between these different modes occurred via an intermittent regime. It turned out that the capsule deformation greatly influenced the orientation dynamics. In several experiments, we also observed shear-induced membrane wrinkling processes.