Well this concept is based on superhydrophobicity. I do not know the working of this coating particularly, but it seems to be superhydrophobic. A superhydrophobic surface(SHS) is one where water has very high mobility i.e. an extremely water repelling surface. Is is due to a surface having low surface energy and a textured topography. They hold very high commercialization potential. Lotus leaf is one natural occuring example of this phenomenon. The research into this field started extensively in 1997. SHS can be employed in variety of applications theoretically i.e. cars, windshields, toilets, ketchup bottles, kettles, phones, power lines, preventing ice accumulation, on boat hulls, on shoes in rain, fabrics, solar cells, around sinks, shower curtains... the potential is unlimited. Many researchers are working on making it possible, and they are very good ones too.<p>So after you have been primed about the subject, what is preventing their wide spread usage? Durability. Not a single one of them is able to sustain mechanical duress. And one of the most widely used chemical is Teflon, which is expensive. Hence, reapplication is not possible time and again. Many researchers are working on it, but a solution remains elusive until now. These sprays are nice such that they open the field, but much more still needs to be done in this field, since these sprays have been in market for at least 5 years now.