Liquid Drops Hurdling Barriers of Various Geometries

Drop manipulation and mobility on a solid surface has received widespread attention. However, how a soft liquid drop interacts with a barrier in the direction of its motion, this question still remains open. This study shows liquid drop hurdling the preconditioned barriers with various geometries displaying superhydrophobic surface. Unlike human being, they cannot anticipate barriers and the only possibility is just head-on confrontation, by deforming themselves to adapt to the barrier's geometry. This study demonstrates experimentally that both the external factors like barriers' geometry and size and internal factors such as drops' initial motion velocity, volume, surface tension, and dynamic viscosity can affect their hurdling dynamics. The hurdling difficulty is quantified through the time and energy loss. These observations throw insight into the dynamics of liquid drops moving on a solid obstacle-equipped surface, which may facilitate the potential applications like coating technology and liquid transportation.