Substrate with a superhydrophobic coating and a method of fabricating thereof

1. A method of forming a superhydrophobic coating, comprising:

mixing a solution comprising an alkyl alkoxysilane, a glycidyl-containing alkoxysilane, an alcohol, ammonium hydroxide, and water for 20 to 60 minutes to form a mixture and applying the mixture onto a substrate;

heating the substrate and the mixture applied thereon, wherein the substrate is functionalized with the alkyl alkoxysilane and the glycidyl-containing alkoxysilane, thereby forming a coated substrate comprising a binding layer on the substrate;

applying a suspension comprising perfluoroalkyl-functionalized silica nanoparticles onto the coated substrate to form a hydrophobic layer on the binding layer, thereby forming the superhydrophobic coating; and

annealing the substrate with the superhydrophobic coating at a temperature in the range of 100° C. to 300° C. for no more than 2 hours,

wherein the alkyl alkoxysilane is selected from the group consisting of methytrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, trimethylethoxysilane, and dimethyldiethoxysilane, and

wherein the glycidyl-containing alkoxysilane is (3-glycidyloxypropyl) trimethoxysilane.

2. The method of claim 1 ,

wherein the mixture is applied onto the substrate by spray-coating, and

wherein the suspension is applied onto the coated substrate by spray-coating.

3. The method of claim 1 , wherein the substrate and the mixture applied thereon are heated at a temperature of 30 to 90° C. for no more than 3 hours.

4. The method of claim 1 , wherein a weight percent of the perfluoroalkyl-functionalized silica nanoparticles in the suspension is in the range of 0.1 wt % to 2.0 wt %, relative to the total weight of the suspension.

5. The method of claim 1 ,

wherein a molar ratio of the glycidyl-containing alkoxysilane to the alkyl alkoxysilane in the solution is from 1:1 to 1:5, and

wherein a molar ratio of the alkyl alkoxysilane to the water in the solution is from 1:3 to 1:6.

6. The method of claim 1 , wherein the perfluoroalkyl-functionalized silica nanoparticles in the suspension are formed by sonicating silica nanoparticles in the presence of a perfluoroalkylsilane.

7. The method of claim 6 , wherein the perfluoroalkylsilane is 1,1,2,2-perfluorooctyltriethoxysilane.

8. The method of claim 6 , wherein an average diameter of the silica nanoparticles is in the range of 1 to 100 nm.

9. The method of claim 1 , wherein three layers of the mixture are applied onto the substrate by spray-coating.

10. The method of claim 1 , wherein the mixture is applied onto the substrate by spray-coating at a spray distance of 14 to 16 cm.

11. The method of claim 1 , wherein the mixture is applied onto the substrate with spray-coating with a pressure of 200 to 400 kPa.

12. The method of claim 1 , wherein three layers of the suspension are applied onto the coated substrate by spray-coating.

13. The method of claim 1 , wherein a weight percent of the perfluoroalkyl-functionalized silica nanoparticles in the suspension is in the range of 0.1 wt % to 1.0 wt %, relative to the total weight of the suspension.

14. The method of claim 1 , wherein the suspension is applied onto the coated substrate by spray-coating at a spray distance of 14 to 16 cm.

15. The method of claim 1 , wherein the suspension is applied onto the coated substrate by spray-coating with a pressure of 200 to 400 kPa.

16. The method of claim 1 , wherein the suspension consists of the perfluoroalkyl-functionalized silica nanoparticles in an alcohol solvent.