Nanostructured coatings and related methods

• US 20070087187A1
• Filed: 10/05/2006
• Published: 04/19/2007
• Est. Priority Date: 07/18/2003
• Status: Active Grant

• Current Assignee: Vitro Flat Glass LLC (Compagnie De Saint-Gobain)
• Original Assignee: PPG Industries Ohio Incorporated (Nouryon BV)
• Inventors: Lu, Songwei, Harris, Caroline, Boykin, Cheri
• Granted Patent: US 8,679,580 B2
• Time in Patent Office: Days
• US Class Current: 428/323
• CPC Class Codes: B01J 21/06 Silicon, titanium, zirconium or hafnium; Oxides or hydroxides thereof
• CPC Class Codes: B01J 21/063 Titanium; Oxides or hydroxides thereof
• CPC Class Codes: B01J 35/39 Photocatalytic properties
• CPC Class Codes: C03C 1/008 for the production of films or coatings
• CPC Class Codes: C03C 17/007 containing a dispersed phase, e.g. particles, fibres or flakes, in a continuous phase
• CPC Class Codes: C03C 17/3417 all coatings being oxide coatings
• CPC Class Codes: C03C 2217/42 consisting of particles only
• CPC Class Codes: C03C 2217/477 Titanium oxide
• CPC Class Codes: C03C 2217/71 Photocatalytic coatings
• CPC Class Codes: C03C 2218/15 from the vapour phase
• CPC Class Codes: C03C 2218/152 by cvd
• CPC Class Codes: C03C 2218/153 by plasma-enhanced cvd
• CPC Class Codes: C23C 16/44 characterised by the method of coating C23C16/04 takes precedence
• CPC Class Codes: Y10T 428/25 Web or sheet containing structurally defined element or component and including a second component containing structurally defined particles

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 nanoparticles; and forcing the fluidized precursor toward the substrate to coat the undercoating with a layer of nanoparticles. Coated substrates according to the present invention exhibit improved durability and increased photocatalytic activity.

Claims

1. A method of making a coated article, comprising:

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

b. fluidizing a precursor for nanoparticles; and

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

2. The method according to claim 1, further comprising passing the fluidized precursor through a high energy zone.

3. The method according to claim 2, wherein the passing step comprises passing the precursor through a high energy zone 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.

4. The method according to claim 1, wherein the fluidizing step comprises atomizing the precursor into an aerosol.

5. The method according to claim 1, wherein the fluidizing step comprises fluidizing a precursor for the titania nanoparticles selected from titanium(IV)isopropoxide, titanium(IV)chloride, titanium(IV)butoxide, titanium(IV)ethoxide, titanium(IV)methoxide, titanium(IV)oxideacetylacetonate, titanium(IV)propoxide and titanium(IV)(triethanolaminato)isopropoxide, or mixtures thereof.

6. The method according to claim 1, wherein the forcing step comprises imparting momentum to the fluidized precursor using a moving gas stream.

7. The method according to claim 1, wherein the deposited undercoating comprises a single layer.

8. The method according to claim 7, wherein the deposited undercoating is selected from tin oxide, silica, titania, alumina, zirconia, zinc oxide, cesium oxide, and alloys and mixtures thereof.

9. The method according to claim 7, 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.

10. The method according to claim 1, wherein the deposited undercoating comprises multiple layers of oxide materials.

11. The method according to claim 10, wherein the deposited undercoating comprises a layer of silica over a layer of tin oxide.

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

13. The method according to claim 1, wherein the nanoparticles have an aspect ratio ranging from 1:

1 to 1;

1,000.

14. The method according to claim 1, wherein the nanoparticles are separated by a distance ranging from 1 nm to 1000 nm.

15. The method according to claim 1, wherein the nanoparticles have a longest dimension ranging from 1 nm to 500 nm.

16. The method according to claim 1, wherein the fluidized precursor is a precursor for titania nanoparticles.

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

18. The method according to claim 1, having a photocatalytic activity 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 nanoparticles comprise titania in an amount of at least 6 μ

g·

cm^{31 2}.

20. A coated substrate made by the process of claim 1.

19. A method of making a coated 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 nanoparticles selected from titanium(IV)isopropoxide, titanium(IV)chloride, titanium(IV)butoxide, titanium(IV)ethoxide, titanium(IV)methoxide, titanium(IV)oxideacetylacetonate, titanium(IV)propoxide and titanium(IV)(triethanolaminato)isopropoxide; and

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