Drop Motion On An Inclined Plane And Evaluation Of Hydrophobic Treatments To Glass

Hydrophobic and anti-rain surface treatments are increasingly used to treat various glass articles such as windscreens, windows, headlamps, wing mirrors, optical lenses, sunglasses, etc. To evaluate the efficiency and durability of these treatments, the smallest volume or critical sliding volume, Vc, of a water drop able to slide down spontaneously under gravity after having been deposited on a vertical treated glass surface have been determined. In this article, a new simplified theory to describe the capillary force retaining the water drops on an inclined plane is proposed and verified practically.