HIGHLY SOLUBLE CARBON NANOTUBES WITH ENHANCED CONDUCTIVITY

• US 20120326093A1
• Filed: 06/22/2012
• Published: 12/27/2012
• Est. Priority Date: 06/24/2011
• Status: Active Grant

• Current Assignee: Brewer Science Inc.
• Original Assignee: Brewer Science Inc.
• Inventors: Landorf, Christopher
• Granted Patent: US 9,157,003 B2
• Time in Patent Office: Days
• US Class Current: 252/500
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: B82Y 40/00 Manufacture or treatment of nanostructures
• CPC Class Codes: C01B 32/174 Derivatisation; Solubilisation; Dispersion in solvents
• CPC Class Codes: C09D 11/52 Electrically conductive inks
• CPC Class Codes: H01B 1/24 the conductive material comprising carbon-silicon compounds, carbon or silicon

Abstract

New methods for preparing carbon nanotube films having enhanced properties are provided. The method broadly provides reacting carbon nanotubes (CNTs) and compounds comprising a polyaromatic moieties in the presence a strong acid. During the reaction process, the polyaromatic moieties noncovalently bond with the carbon nanotubes. Additionally, the functionalizing moieties are further functionalized by the strong acid. This dual functionalization allows the CNTs to be dispersed at concentrations greater than 0.5 g/L in solution without damaging their desirable electronic and physical properties. The resulting solutions are stable on the shelf for months without observable bundling, and can be incorporated into solutions for printing conductive traces by a variety of means, including inkjet, screen, flexographic, gravure printing, or spin and spray coating.

Claims

1. A method of preparing a carbon nanotube dispersion, said method comprising:

providing a mixture of carbon nanotubes, a compound comprising at least one polyaromatic moiety, and an acid;

noncovalently bonding said carbon nanotubes with said compound comprising at least one polyaromatic moiety; and

reacting said acid with said at least one polyaromatic moiety.

2. The method of claim 1, wherein before said providing, at least some of said carbon nanotubes are bundled or clustered, and during said providing, said acid separates at least some of said bundled or clustered carbon nanotubes.

3. The method of claim 1, wherein said noncovalently bonding and said reacting occur substantially simultaneously.

4. The method of claim 1, wherein said providing comprises first mixing said carbon nanotubes with said acid, and then adding said compound comprising at least one polyaromatic moiety.

5. The method of claim 4, wherein at least some of said carbon nanotubes are bundled or clustered, and during said mixing, said acid separates at least some of said bundled or clustered carbon nanotubes.

6. The method of claim 1, wherein said providing comprises first mixing said compound comprising at least one polyaromatic moiety with said acid, and then adding said carbon nanotubes.

7. The method of claim 1, wherein said carbon nanotubes are selected from the group consisting of single-walled, double-walled, and multi-walled carbon nanotubes.

8. The method of claim 1, wherein said compound comprising at least one aromatic moiety is selected from the group consisting of substituted and unsubstituted compounds selected from the group consisting of naphthalene, anthracene, phenanthracene, pyrene, tetracene, tetraphene, chrysene, triphenylene, pentacene, pentaphene, perylene, benzo[a]pyrene, coronene, antanthrene, corannulene, ovalene, graphene, fullerene, cycloparaphenylene, polyparaphenylene, cyclophene, and compounds containing moieties of the foregoing.

9. The method of claim 1, wherein said acid has a pKa of less than about −

1.

10. The method of claim 1, wherein said acid is selected from the group consisting of sulfuric acid, chlorosulfonic acid, triflic acid, p-toluenesulfonic acid, and mixtures thereof.

11. The method of claim 1, wherein said carbon nanotubes and compounds comprising at least one polyaromatic moiety are provided in quantities such that the molar ratio of carbon nanotubes to polyaromatic moieties is from about 25:

75 to about 75;

25.

12. The method of claim 1, wherein said acid is present at levels of from about 90% to about 99.99% by weight, based upon the total weight of the dispersion taken as 100% by weight.

13. The method of claim 1, wherein the carbon nanotube dispersion resulting from said noncovalently bonding and reacting has a carbon nanotube concentration of at least about 0.05% by weight, based upon the total weight of the dispersion taken as 100% by weight.

14. The method of claim 1, wherein said carbon nanotube dispersion resulting from said noncovalently bonding and reacting can be formed into a film having a sheet resistance of less than about 7,000 Ω

/sq.

23. A dispersion prepared according to the method of claim 1.

24. The dispersion of claim 23, wherein said carbon nanotubes are selected from the group consisting of single-walled, double-walled, and multi-walled carbon nanotubes.

25. The dispersion of claim 23, wherein said compound comprising at least one aromatic moiety is selected from the group consisting of substituted and unsubstituted compounds selected from the group consisting of naphthalene, anthracene, phenanthracene, pyrene, tetracene, tetraphene, chrysene, triphenylene, pentacene, pentaphene, perylene, benzo[a]pyrene, coronene, antanthrene, corannulene, ovalene, graphene, fullerene, cycloparaphenylene, polyparaphenylene, cyclophene, and compounds containing moieties of the foregoing.

26. The dispersion of claim 23, wherein said acid has a pKa of less than about −

1.

27. The dispersion of claim 23, wherein said acid is selected from the group consisting of sulfuric acid, chlorosulfonic acid, triflic acid, p-toluenesulfonic acid, and mixtures thereof.

28. The dispersion of claim 23, wherein said carbon nanotubes and compounds comprising at least one polyaromatic moiety are provided in quantities such that the molar ratio of carbon nanotubes to polyaromatic moieties is from about 25:

75 to about 75;

25.

29. The dispersion of claim 23, wherein the carbon nanotube concentration in the dispersion is at least about 0.05% by weight, based upon the total weight of the dispersion taken as 100% by weight.

30. The dispersion of claim 26, wherein said carbon nanotube dispersion resulting from said noncovalently bonding and reacting can be formed into a film having a sheet resistance of less than about 7,000 Ω

/sq.

15. A dispersion comprising carbon nanotubes noncovalently bonded to compounds comprising respective polyaromatic moieties, at least some of said polyaromatic moieties being reacted with an acid, said dispersion:

having a carbon nanotube concentration of at least about 0.05% by weight, based upon the total weight of the dispersion taken as 100% by weight; and

being formable into a film having a sheet resistance of less than about 7,000 Ω

/sq.

16. The dispersion of claim 15, wherein said carbon nanotubes are selected from the group consisting of single-walled, double-walled, and multi-walled carbon nanotubes.

17. The dispersion of claim 15, wherein said compound comprising at least one aromatic moiety is selected from the group consisting of substituted and unsubstituted compounds selected from the group consisting of naphthalene, anthracene, phenanthracene, pyrene, tetracene, tetraphene, chrysene, triphenylene, pentacene, pentaphene, perylene, benzo[a]pyrene, coronene, antanthrene, corannulene, ovalene, graphene, fullerene, cycloparaphenylene, polyparaphenylene, cyclophene, and compounds containing moieties of the foregoing.

18. The dispersion of claim 15, wherein said acid has a pKa of less than about −

1.

19. The dispersion of claim 15, wherein said acid is selected from the group consisting of sulfuric acid, chlorosulfonic acid, triflic acid, p-toluenesulfonic acid, and mixtures thereof.

20. The dispersion of claim 15, wherein said carbon nanotubes and compounds comprising at least one polyaromatic moiety are provided in quantities such that the molar ratio of carbon nanotubes to polyaromatic moieties is from about 25:

75 to about 75;

25,

21. The dispersion of claim 15, wherein the carbon nanotube concentration in the dispersion is at least about 0.05% by weight, based upon the total weight of the dispersion taken as 100% by weight.

22. The dispersion of claim 15, wherein the dispersion can be formed into a film having a sheet resistance of less than about 7,000 Ω

/sq.