Coating compositions for producing transparent super-hydrophobic surfaces
View Patent ↗A coating composition and process for generating transparent, near-transparent, and semi-transparent super-hydrophobic coatings on surfaces having a contact angle of greater than 165 degrees. The composition comprises hydrophobic nanoparticles of silsesquioxanes containing adhesion promoter groups and low surface energy groups.
1. A coating on a surface, said coating imparting temporary hydrophobic characteristics to said surface, said coating having a contact angle of at least 165 degrees with water, wherein the coating is formed by:
applying nanoparticles of a fluorinated silsesquioxane having a particle size in the range of about 7 nm to about 600 nm dispersed in a solvent to a surface, said silsesquioxane having pendant groups R 1 and R 2 being bonded directly to silicon, R 1 comprising an alkyl group or an aryl group and R 2 comprising an alkyl group substituted with one of an adhesion promoter group or a cross linking group; and
allowing said solvent to evaporate, said solvent being selected from the group consisting of hydrocarbons, alcohols, mineral spirits, and mixtures thereof.
2. The coating of claim 1 , wherein the surface is metal, plastic, wood, glass, or ceramic.
3. The coating of claim 1 , wherein the surface is painted or waxed prior to applying said nanoparticles dispersed in said solvent.
4. The coating of claim 1 , wherein said adhesion promoter comprises a urethane polymer.
5. The coating of claim 1 , wherein said nanoparticles adhere to the substrate in the absence of a binder.
6. The coating of claim 1 , wherein said silsesquioxane includes silicon-silicon bonding.