Nanostructured coatings and related methods

• US 20050031876A1
• Filed: 07/22/2004
• Published: 02/10/2005
• Est. Priority Date: 07/18/2003
• Status: Abandoned Application

• Current Assignee: PPG Industries Ohio Incorporated (Nouryon BV)
• Original Assignee: PPG Industries Ohio Incorporated (Nouryon BV)
• Inventors: Boykin, Cheri M., Harris, Caroline S., Lu, Songwei
• Application Number:
  US10/897,847
• Publication Number:
  US 20050031876A1
• Time in Patent Office: Days
• US Class Current: 428/428
• CPC Class Codes: B01J 35/39 Photocatalytic properties
• CPC Class Codes: B05D 1/06 Applying particulate materials
• CPC Class Codes: B05D 2203/35 Glass
• CPC Class Codes: B05D 2601/24 Titanium dioxide, e.g. rutile
• CPC Class Codes: B32B 17/10174 Coatings of a metallic or dielectric material on a constituent layer of glass or polymer
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C03C 17/006 with materials of composite character
• CPC Class Codes: C03C 17/3417 all coatings being oxide coatings
• CPC Class Codes: C03C 2217/40 Coatings comprising at least one inhomogeneous layer
• CPC Class Codes: C03C 2217/71 Photocatalytic coatings
• CPC Class Codes: C03C 2218/112 by spraying
• CPC Class Codes: C03C 23/00 Other surface treatment of glass not in the form of fibres or filaments
• CPC Class Codes: C03C 23/0005 by irradiation
• CPC Class Codes: C23C 10/00 Solid state diffusion of only metal elements or silicon into metallic material surfaces
• CPC Class Codes: C23C 16/34 Nitrides C23C16/303 takes precedence
• CPC Class Codes: C23C 16/402 Silicon dioxide
• CPC Class Codes: C23C 16/405 of refractory metals or yttrium
• CPC Class Codes: C23C 16/407 of zinc, germanium, cadmium, indium, tin, thallium or bismuth
• CPC Class Codes: C23C 18/00 Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating
• CPC Class Codes: C23C 4/123 Spraying molten metal

Abstract

A coated substrate and methods for making the coated substrate are disclosed. The method entails depositing an undercoating over at least a portion of the substrate; fluidizing a precursor for nanostructures; and forcing the fluidized precursor toward the substrate to coat the undercoating with a layer of nanostructures. Coated substrates according to the present invention exhibit improved durability and increased photocatalytic activity.

Claims

1. A substrate coated with nanostructures formed by a process comprising:

a. depositing an undercoating over at least a portion of the substrate;

b. fluidizing a precursor for nanostructures; and

c. forcing the fluidized precursor toward the substrate to coat the undercoating with nanostructures.

2. The substrate of claim 1, formed by a process further comprising passing the fluidized precursor through a high energy zone.

3. The substrate according to claim 1, wherein the deposited undercoating comprises a single layer.

4. The substrate according to claim 3, wherein the deposited undercoating is selected from tin oxide, silica, titania, alumina, zirconia, zinc oxide and alloys and mixtures thereof.

5. The substrate according to claim 3, wherein the deposited undercoating comprises a mixture of titania and silica;

silica and tin oxide;

alumina and tin oxide;

alumina and zirconia;

alumina and zinc oxide;

silica and zirconia;

silica and zinc oxide;

alumina and silica;

titania and alumina;

or alumina, silica and titania.

6. The substrate according to claim 1, wherein the deposited undercoating comprises multiple layers of coating.

7. The substrate according to claim 6, wherein the deposited undercoating comprises a layer of silica over a layer of tin oxide.

8. The substrate according to claim 1, wherein the deposited undercoating has a thickness of at least 10 nm.

9. The substrate according to claim 1, wherein the nanostructures have an aspect ratio ranging from 1:

1 to 1;

1,000.

10. The substrate according to claim 1, wherein the nanostructures are separated by a distance ranging from 1 nm to 1000 nm.

11. The substrate according to claim 1, wherein the nanostructures have a longest dimension ranging from 1 nm to 500 nm.

12. The substrate according to claim 1, wherein the fluidized precursor is a precursor for titania nanostructures.

13. The substrate according to claim 12, wherein the fluidized precursor is selected from titanium tetra iso-propoxide, titanium tetra chloride, titanium tetra n-butoxide, titanium tetraethoxide, titanium tetra methoxide, titanyl acetylacetonate, titanium tetrapropoxide and titanium tetra (triethanolaminato).

14. The substrate according to claim 1, wherein the substrate is glass.

15. The substrate according to claim 1, having a PCA of at least 33×

10<sup>−

3</sup> min<sup>−

1</sup>·

cm<sup>−

1</sup> wherein the undercoating is at least 54 nm thick and the nanostructures have a density of at least 6 □

g·

cm<sup>−

2</sup>.

16. A glass substrate coated with a layer of nanostructures formed by a process comprising:

a. depositing an undercoating comprising a mixture of silica and alumina over at least a portion of the substrate;

b. fluidizing a precursor for titania nanostructures selected from titanium tetra iso-propoxide, titanium tetra chloride, titanium tetra n-butoxide, titanium tetraethoxide, titanium tetra methoxide, titanyl acetylacetonate, titanium tetrapropoxide and titanium tetra (triethanolaminato); and

c. forcing the fluidized precursor toward the substrate to coat the undercoating with a layer of nanostructures.

17. The substrate according to claim 16, formed by a process further comprising passing the fluidized precursor through a high energy zone.

18. The substrate according to claim 16, wherein the nanostructures have a longest dimension ranging from 1 nm to 500 nm.

19. A method of making a coated substrate comprising:

a. depositing an undercoating over at least a portion of the substrate;

b. fluidizing a precursor for nanostructures; and

c. forcing the fluidized precursor toward the substrate to coat the undercoating with nanostructures.

20. The method of claim 19, further comprising passing the fluidized precursor through a high energy zone.

21. The method according to claim 20, wherein passing comprises passing the precursor through a high energy zones selected from a hot wall reactor, a chemical vapor particle deposition reactor, a combustion deposition reactor, a plasma chamber, laser beam and a microwave chamber.

22. The method according to claim 19, wherein fluidizing comprises atomizing the precursor into an aerosol.

23. The method according to claim 19, wherein fluidizing comprises fluidizing a precursor for the titania nanostructures selected from titanium tetra iso-propoxide, titanium tetra chloride, titanium tetra n-butoxide, titanium tetraethoxide, titanium tetra methoxide, titanyl acetylacetonate, titanium tetrapropoxide and titanium tetra (triethanolaminato).

24. The method according to claim 19, wherein forcing comprises imparting momentum to the fluidized precursor using a moving gas stream.

25. A method of making a coated a substrate comprising:

depositing an undercoating comprising a mixture of silica and alumina over at least a portion of the substrate;

fluidizing a precursor for titania nanostructures selected from titanium tetra iso-propoxide, titanium tetra chloride, titanium tetra n-butoxide, titanium tetraethoxide, titanium tetra methoxide, titanyl acetylacetonate, titanium tetrapropoxide and titanium tetra (triethanolaminato); and

forcing the fluidized precursor toward the substrate using compressed gas, to coat the undercoating with a layer of nanostructures.

26. The method according to claim 25, further comprising passing the fluidized precursor through a high energy zone.

27. The method according to claim 25, wherein the nanostructures have a longest dimension ranging from 1 nm to 500 nm.

28. A coated substrate comprising:

a substrate;

an undercoating over at least a portion of the substrate; and

a layer of nanostructures over at least a portion of the undercoating, wherein the undercoating is coated with a layer of nanostructures.

29. The coated substrate according to claim 28, wherein the undercoating comprising a single layer.

30. The coated substrate according to claim 29, wherein the undercoating is selected from tin oxide, silica, titania, alumina, zirconia, zinc oxide and alloys and mixtures thereof.

31. The coated substrate according to claim 29, wherein the undercoating comprises a mixture of titania and silica;

silica and tin oxide;

alumina and tin oxide;

alumina and zirconia;

alumina and zinc oxide;

silica and zirconia;

silica and zinc oxide;

alumina and silica;

titania and alumina, or alumina, silica and titania.

32. The coated substrate according to claim 29, wherein the nanostructures have a longest dimension ranging from 1 nm to 500 nm.