SUPERHYDROPHOBIC COATINGS AND METHODS FOR THEIR PREPARATION

• US 20140238263A1
• Filed: 06/01/2012
• Published: 08/28/2014
• Est. Priority Date: 06/01/2011
• Status: Active Grant

• Current Assignee: University of North Carolina At Chapel Hill (University of North Carolina System)
• Original Assignee: University of North Carolina At Chapel Hill (University of North Carolina System)
• Inventors: Shin, Jae Ho, Scheonfisch, Mark H., Privett, Ben, Youn, Johnghae
• Granted Patent: US 9,675,994 B2
• Time in Patent Office: Days
• US Class Current: 106/2
• CPC Class Codes: B05D 1/02 performed by spraying
• CPC Class Codes: C01B 33/128 by acidic treatment of aqueous silicate solutions
• CPC Class Codes: C01B 33/142 by acidic treatment of silicates
• CPC Class Codes: C01B 33/143 of aqueous solutions of silicates
• CPC Class Codes: C09D 1/00 Coating compositions, e.g. paints, varnishes or lacquers, based on inorganic substances

Abstract

Superhydrophobic coatings and compositions and methods for preparing superhydrophobic coatings and compositions are described herein whereby the coatings and compositions are prepared under mild conditions, yet the methods are amenable to chemical functionalization of the coatings and components therein. The methods are useful for tuning and optimizing the physical properties of the coatings. In an embodiment, the coatings comprise nanostructured fluorinated silica colloids.

Claims

1. A method of preparing a coating, comprising:

a) contacting under mild conditions a silica-containing colloid with two or more silanes to prepare a first colloid mixture,

b) contacting under mild conditions said first colloid mixture with an acid, wherein a superhydrophobic coating is prepared.

5. The method of claim 1, wherein said colloid comprises silica nanoparticles.

8. The method of claim 1, wherein at least one of said silanes is a fluoroalkoxysilane.

9. The method of claim 8, wherein said fluoroalkoxysilane is (heptadecafluoro-1,1,2,2-tetrahydrodecyl)trimethoxysilane.

10. The method of claim 1, wherein at least one of said silanes is a backbone silane selected from the group consisting of methyltrimethoxysilane (MTMOS), butyltrimethoxysilane (BTMOS), tetramethylorthosilicate (TMOS), tetraethylorthosilicate (TEOS) or their combinations thereof.

22. The method of claim 1, further comprising:

c) contacting the product of said b) with a solid substrate.

25. The method of claim 22, wherein said solid substrate is selected from the group consisting of medical devices, plumbing fixtures, condenser coils, optical surfaces, boat hulls and aircraft.

28. A method of reducing microbial adhesion, condensation or ice buildup, comprising:

contacting the coating prepared according to claim 1 with a solid substrate.

32. The method of claim 28, wherein said microbial adhesion is a bacterial adhesion.

35. The method of claim 28, wherein said microbial adhesion is a fungal adhesion.

36. The method of claim 35, wherein said fungal adhesion comprises an adhesion of a Candida species.

47. The method of claim 22, wherein said contacting comprises spray coating.

48. The method of claim 28, wherein said contacting comprises spray coating.

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41. A coating composition comprising, nanostructured fluorinated silica colloids, and a fluoroalkoxysilane covalently linked to at least one additional silane.

42. The coating composition of claim 41, wherein the at least one additional silane is a backbone silane.

43. The coating composition of claim 41, wherein said fluoroalkoxysilane is selected from the group consisting of heptadecafluoro-1,1,2-2-tetrahydrodecyl)triethoxysilane;

(3,3,3-trifluoropropyl)trimethoxysilane;

heptadecafluoro-1,1,2-2-tetrahydrodecyl)trimethoxysilane;

heptadecafluoro-1,1,2-2-tetrahydrodecyl)trichlorosilane;

(tridecafluoro-1,1,2,2-tetrahydrooctyl)triethoxysilane; and

(perfluoroalkyl)ethyltriethoxysilane.

44. The coating composition of claim 41, wherein said fluoroalkoxysilane is heptadecafluoro-1,1,2-2-tetrahydrodecyl)trimethoxysilane and said additional silane is methyltrimethoxysilane.

45. The coating composition of claim 41, wherein said composition is stable for contacting with a substrate by spray coating.

46. A method of coating a substrate comprising:

contacting said substrate by spray coating a composition comprising, nanostructured fluorinated silica colloids, and a fluoroalkoxysilane covalently linked to at least one additional silane to prepare a coated substrate.