Fig. 1.

Schematic of the experiment. A millimeter-size water drop is placed on hydrophobic pillars (side a = 19 μm, height h = 100 μm, spacing b = 80 μm, as shown in the inset), and pressed with a superhydrophobic plate, until inducing a transition from Cassie to Wenzel state. Then the plate motion is reversed and side views allow us to extract the drop profile and surface energy as a function of distance z. The force exerted by the liquid on its substrate is simultaneously measured with a sensitive force sensor.