Dynamic Air Layer on Textured Superhydrophobic Surfaces

We provide an experimental demonstration that a novel macroscopic, dynamic continuous air layer or plastron can be sustained indefinitely on textured super-hydrophobic surfaces in air-supersaturated water by a natural. gas influx mechanism. This type of plastron is an intermediate state between Leidenfrost vapor layers on superheated surfaces and the equilibrium Cassie-Baxter wetting state on textured superhydrophobic surfaces. We show that such a plastron can sustained on the surface of a centimeter-sized superhydrophobic sphere immersed in heated water and variations of its dynamic behavior with air saturation of the water can be regulated by rapid changes of the water temperature. The simple experimental setup allows for quantification of the air flux into the plastron and identification of the air transport model of the plastron growtb. Both the observed growth dynamics of such plastrons and millimeter sized air bubbles seeded on the hydrophihc Surface Under identical air supersaturated solution conditions are consistent with the predictions of a well mixed gas transport model.