A hydrophobic coating is reported to last anywhere from 2-8 months in direct sunlight and outdoor conditions before a top-coat re-coating is needed. Indoor and covered outdoor systems provide a lifespan of around one year or more
A hydrophobic surface is a low energy surface that repels water and is resistant to wetting. Their moisture contact angle calculations would mark a surface as hydrophobic, if the contact angle of the water droplet exceeds 90 degrees. Exceed the contact angle limit of 150 degrees and the surface is superhydrophobic.
A Superhydrophobic coating is a coating with a water contact angle above 150 degrees and a slipping angle below 10 degrees. Hydrophobic surfaces also serve to reduce water wetting of surfaces. Due to its exceptional properties such as self-cleaning, anti-icing, anti-friction and others, superhydrophobic surfaces are highly desired for several applications.
Its main function is to protect the surface from the water and repel. Inspired by nature, hydrophobic paint can be derived as, firstly the solid surface is chemically enhanced with a low surface material. And second, the nano and micro-structures formed on the substrate to prevent water from becoming fully in contact with the surface.
In nature there are many hydrophobic surfaces like lotus leaves, butterfly wings, duck feathers. Hydrophobic materials are used for separating oil from water, preventing oil spills and isolating chemical substances from polar compounds.
Superhydrophobic coating is a thin layer that repels water. Superhydrophobic coatings are made of composite materials where roughness is given by one component and low surface energy by the other.