Science Daily, December 13, 2017
To gain better control over the flow of water on superhydrophobic materials, scientists have been etching paths into coatings for the liquid to follow. And although water will take the designated path, it can leave behind a wet trail as the rolling droplets have a different contact angle at the front and back. An international team of researchers (China, US – UMass Amherst) has developed a technique to make the tracks hydrophobic which is critical for keeping water droplets’ spherical shape and minimizing the difference in the front and back contact angles. Testing showed that water flowed along the designated paths without leaving a trace… read more.  TECHNICAL ARTICLE
From the technical article