TRANSPARENT CONDUCTORS AND METHODS FOR FABRICATING TRANSPARENT CONDUCTORS

• US 20090189124A1
• Filed: 01/28/2008
• Published: 07/30/2009
• Est. Priority Date: 01/28/2008
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Smith, Peter A., Guiheen, James V., Lem, Kwok Wai, Wang, Yubing
• Granted Patent: US 7,960,027 B2
• Time in Patent Office: Days
• US Class Current: 252/500
• CPC Class Codes: H01B 1/124 Intrinsically conductive polymers
• CPC Class Codes: Y10T 428/31551 Of polyamidoester [polyurethane, polyisocyanate, polycarbamate, etc.]
• CPC Class Codes: Y10T 428/31678 Of metal

Abstract

Transparent conductors and methods for fabricating transparent conductors are provided. In one exemplary embodiment, a transparent conductor comprises a substrate having a surface and a transparent conductive coating disposed on the surface of the substrate. The transparent conductive coating has a plurality of conductive components of at least one type and an aliphatic isocyanate-based polyurethane component.

Claims

1. A transparent conductor comprising:

a substrate having a surface;

a transparent conductive coating disposed on the surface of the substrate, the transparent conductive coating having a plurality of conductive components of at least one type and an aliphatic isocyanate-based polyurethane component.

2. The transparent conductor of claim 1, wherein the aliphatic isocyanate-based polyurethane component is an aliphatic isocyanate-based polyurethane having no more than 50% crosslinking.

3. The transparent conductor of claim 1, wherein the aliphatic isocyanate-based polyurethane component is an aliphatic isocyanate-based polyurethane formed from an oligomer with a molecular weight of at least 2500.

4. The transparent conductor of claim 1, wherein the aliphatic isocyanate-based polyurethane component is physically or chemically bonded to the surface of the substrate.

5. The transparent conductor of claim 4, wherein the aliphatic isocyanate-based polyurethane component is a polar aliphatic isocyanate-based polyurethane and the substrate has a substantially polar molecular surface.

6. The transparent conductor of claim 4, wherein at least a substantial portion of molecules at the surface of the substrate comprises alcohol (—

OH)-terminated molecules and the aliphatic isocyanate-based polyurethane component comprises an isocyanate (—

NCO)-terminated polyurethane.

7. The transparent conductor of claim 4, wherein at least a substantial portion of molecules at the surface of the substrate comprises acid (—

COOH)-terminated molecules and the aliphatic isocyanate-based polyurethane component comprises an isocyanate (—

NCO)-terminated polyurethane.

8. The transparent conductor of claim 4, wherein at least a substantial portion of molecules at the surface of the substrate comprises acid (—

COOH)-terminated molecules and the aliphatic isocyanate-based polyurethane component comprises an alcohol (—

OH)-terminated polyurethane.

9. The transparent conductor of claim 4, wherein at least a substantial portion of molecules at the surface of the substrate comprises acid (—

COOH)-terminated molecules and the aliphatic isocyanate-based polyurethane component comprises an amine (—

NH₂)-terminated polyurethane.

10. The transparent conductor of claim 1, wherein the aliphatic isocyanate-based polyurethane component is a segmented polyurethane comprising hard and soft segments.

11. The transparent conductor of claim 1, wherein the plurality of conductive components comprises a plurality of nanowires.

12. The transparent conductor of claim 1, wherein the transparent conductor has a total light transmittance of no less than about 50% and a surface resistivity it the range of about 10¹ to about 10¹² Ω

/sq.

13. A method for fabricating a transparent conductor, the method comprising the steps of:

providing a substrate having a surface;

mixing a binder comprising an aliphatic isocyanate-based polyurethane component and a first solvent to form a binder precursor;

applying the binder precursor to the surface of the substrate;

at least partially evaporating the first solvent from the binder precursor such that the binder remains on the surface of the substrate;

forming a dispersion comprising a plurality of conductive components of at least one type and a second solvent;

applying the dispersion to the binder; and

at least partially evaporating the second solvent from the dispersion and forming a transparent conductive coating on the surface of the substrate.

14. The method of claim 13, wherein the step of mixing comprises the step of mixing an aliphatic isocyanate-based polyurethane having no more than 50% crosslinking and the first solvent.

15. The method of claim 13, wherein the step of mixing comprises the step of mixing an aliphatic isocyanate-based polyurethane formed from an oligomer with a molecular weight of at least 2500 and the first solvent.

16. The method of claim 13, wherein the surface of the substrate has a substantially polar surface and the step of mixing comprises the step of mixing a polar aliphatic isocyanate-based polyurethane and the first solvent.

17. The method of claim 13, wherein at least a substantial portion of molecules at the surface of the substrate comprises alcohol (—

OH)-terminated molecules and the step of mixing comprises the step of mixing the first solvent and the aliphatic isocyanate-based polyurethane component comprising an isocyanate (—

NCO)-terminated polyurethane.

18. The method of claim 13, wherein at least a substantial portion of molecules at the surface of the substrate comprises acid (—

COOH)-terminated molecules and the step of mixing comprises the step of mixing the first solvent and the aliphatic isocyanate-based polyurethane component comprising an isocyanate (—

NCO)-terminated polyurethane.

19. The method of claim 13, wherein at least a substantial portion of molecules at the surface of the substrate comprises acid (—

COOH)-terminated molecules and the step of mixing comprises the step of mixing the first solvent and the aliphatic isocyanate-based polyurethane component comprising an alcohol (—

OH)-terminated polyurethane.

20. The method of claim 13, wherein the surface of the substrate comprises acid (—

COOH)-terminated molecules and the step of mixing comprises the step of mixing the first solvent and the aliphatic isocyanate-based polyurethane component comprising an amine (—

NH₂)-terminated polyurethane.

21. The method of claim 13, wherein the first solvent is water, the aliphatic isocyanate-based polyurethane component comprises a water-borne or water-soluble copolymer of aliphatic polyurethane, and the step of mixing comprises the step of mixing the water and the water-borne or water-soluble copolymer of aliphatic polyurethane.

22. The method of claim 13, wherein the step of mixing comprises the step of mixing the aliphatic isocyanate-based polyurethane component and the first solvent to form a phase stable heterogeneous mixture.

23. The method of claim 13, wherein the step of forming a dispersion comprising a plurality of conductive components of at least one type and a second solvent comprises the step of forming the dispersion comprising the plurality of conductive components of at least one type and the second solvent that is the same as the first solvent.

24. The method of claim 13, wherein the step of applying the dispersion to the binder further comprises the step of at least partially dissolving the binder so that at least a portion of the plurality of conductive components becomes embedded in the binder.

25. A method for fabricating a transparent conductor, the method comprising the steps of:

providing a substrate having a surface;

forming a dispersion comprising a plurality of conductive components of at least one type and a solvent;

applying the dispersion to the surface of the substrate and allowing the solvent to soften the substrate so that at least a portion of the plurality of conductive components becomes at least partially embedded in the substrate; and

at least partially evaporating the solvent from the dispersion.