Retraction and freezing of a water film on ice

We investigate experimentally the different shapes taken by a water drop freezing during its impact on a cold surface. We show that these shapes are formed by a water film that remains on top of the first formed ice layer. The capillary hydrodynamics of this water film dewetting on its own ice, coupled with its vertical solidification, is thus quantitatively characterized, allowing us to understand and predict the formation of the emerging patterns. Finally, this experiment enables us to study the contact angle dynamics, giving deep insight into the wetting of water on ice.