The combination of low surface energy and nano-structured features enables the superhydrophobic performance of the surface.
Water droplets coming in contact with a superhydrophobic surface will form nearly spherical beads, as shown in the
images above, with a water contact angle above 150°.
Superhydrophobic surfaces are often referred to as self-cleaning. Any contaminants, either inorganic or organic, on such
surfaces are readily picked up by water droplets and removed from the surface when the water droplets roll off.
Whereas water on a superhydrophobic surface has a high contact angle, water on a superhydrophilic surface will have a
contact angle that approaches zero degrees. There are several benefits of this interaction. For example, since beads
of water do not form, the natural evaporation process does not produce water marks on the glass surface as it would
with normal glass. Additionally, superhydrophilic surfaces can have anti-fogging properties, as it takes longer for
glass droplets to reduce visibility.
In 2020, NASA will be sending Engi-Mat’s proprietary coated fabric to Mars on the next rover mission. See here.