SUPERHYDROPHILIC COATINGS

• US 20080268229A1
• Filed: 08/09/2006
• Published: 10/30/2008
• Est. Priority Date: 08/09/2006
• Status: Abandoned Application

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Cohen, Robert E., Rubner, Michael F., Lee, Daeyeon
• Application Number:
  US11/463,507
• Publication Number:
  US 20080268229A1
• Time in Patent Office: Days
• US Class Current: 428/323
• CPC Class Codes: C03C 17/001 General methods for coating; Devices therefor
• CPC Class Codes: C03C 17/007 containing a dispersed phase, e.g. particles, fibres or flakes, in a continuous phase
• CPC Class Codes: C03C 17/23 Oxides C03C17/02 takes precedence
• CPC Class Codes: C03C 2217/212 TiO2
• CPC Class Codes: C03C 2217/213 SiO2
• CPC Class Codes: C03C 2217/42 consisting of particles only
• CPC Class Codes: C03C 2217/75 Hydrophilic and oleophilic coatings
• CPC Class Codes: C04B 35/14 based on silica
• CPC Class Codes: C04B 35/46 based on titanium oxides or titanates containing also zirconium or hafnium oxides, zirconates or hafnates C04B35/49
• CPC Class Codes: G02B 1/118 having sub-optical wavelength surface structures designed to provide an enhanced transmittance, e.g. moth-eye structures
• CPC Class Codes: G02B 1/18 Coatings for keeping optical surfaces clean, e.g. hydrophobic or photo-catalytic films G02B1/16 takes precedence
• CPC Class Codes: G02B 27/0006 with means to keep optical surfaces clean, e.g. by preventing or removing dirt, stains, contamination, condensation G02B1/18 takes precedence; cleaning in general B08B
• 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 superhydrophilic coating on a substrate can be antireflective and antifogging. The coating can remain antireflective and antifogging for extended periods. The coating can include oppositely charge inorganic nanoparticles, and can be substantially free of an organic polymer.

Claims

1. A superhydrophilic surface comprising a first plurality of inorganic nanoparticles arranged on a substrate.

2. The surface of claim 1, wherein the substrate is substantially transparent.

3. The surface of claim 2, wherein the superhydrophilic surface is substantially transparent.

4. The surface of claim 3, wherein the surface has a refractive index of less than 1.3.

5. The surface of claim 1, wherein the surface further comprises a second plurality of inorganic nanoparticles.

6. The surface of claim 5, wherein the first plurality of inorganic nanoparticles has an opposite electrostatic charge to the second plurality of inorganic nanoparticles.

7. The surface of claim 5, wherein the first plurality of inorganic nanoparticles has a different average particle size than the second plurality of inorganic nanoparticles.

8. The surface of claim 5, wherein the surface is substantially free of an organic polymer.

9. The surface of claim 5, wherein the first plurality of inorganic nanoparticles includes a plurality of silicon dioxide nanoparticles.

10. The surface of claim 9, wherein the second plurality of inorganic nanoparticles includes a plurality of titanium dioxide nanoparticles.

11. The surface of claim 10, wherein the surface is substantially free of an organic polymer.

12. A method of treating a surface comprising:

depositing a first plurality of inorganic nanoparticles having a first electrostatic charge on a substrate; and

depositing an oppositely charged polyelectrolyte over the first plurality of inorganic nanoparticles.

13. The method of claim 12, wherein the oppositely charged polyelectrolyte includes a second plurality of inorganic nanoparticles.

14. The method of claim 13, wherein the first plurality of inorganic nanoparticles has a different average particle size than the second plurality of inorganic nanoparticles.

15. The method of claim 13, wherein the first plurality of inorganic nanoparticles includes a plurality of silicon dioxide nanoparticles.

16. The method of claim 15, wherein the second plurality of inorganic nanoparticles includes a plurality of titanium dioxide nanoparticles.

17. The method of claim 12, further comprising heating the substrate to a temperature of greater than 500°

C.

18. The method of claim 12, further comprising repeating the steps of depositing a first plurality of inorganic nanoparticles having a first electrostatic charge on a substrate and depositing an oppositely charged polyelectrolyte over the first plurality of inorganic nanoparticles;

thereby forming an electrostatic multilayer.

19. The method of claim 18, wherein the electrostatic multilayer is substantially free of an organic polymer.