Alignment of carbon nanotubes on a substrate via solution deposition

• US 20080020487A1
• Filed: 09/13/2005
• Published: 01/24/2008
• Est. Priority Date: 09/16/2004
• Status: Abandoned Application

• Current Assignee: E. I. du Pont de Nemours and Company (Corteva, Inc.)
• Original Assignee: E. I. du Pont de Nemours and Company (Corteva, Inc.)
• Inventors: McLean, Robert, Zheng, Ming
• Application Number:
  US11/225,442
• Publication Number:
  US 20080020487A1
• Time in Patent Office: Days
• US Class Current: 438/1
• 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 2202/02 Single-walled nanotubes
• CPC Class Codes: C01B 2202/06 Multi-walled nanotubes
• CPC Class Codes: C01B 2202/08 Aligned nanotubes
• CPC Class Codes: C01B 32/168 After-treatment
• CPC Class Codes: C01B 32/17 Purification

Abstract

Carbon nanotubes, associated with a charged dispersant are aligned on a substrate by deposition on the substrate directly from solution. Preferred dispersants are charged polymers such as biopolymers.

Claims

1. A method for aligning a population of carbon nanotubes on a substrate comprising:

a) providing a population of carbon nanotubes associated with a charged dispersant in solution;

b) depositing the solution of (a) on a substrate whereby the population of carbon nanotubes are aligned.

6. A method according to either claim 1 or claim 2 wherein the charged dispersant is a polymer.

7. A method according to claim 6, wherein the polymer is a biopolymer.

8. A method according to claim 7 wherein the biopolymer is selected from the group consisting of nucleic acids, polypeptides, and peptide nucleic acids.

9. A method according to either of claims 1 or 2 wherein the substrate is selected from the group consisting of silicon, silicon dioxide, glass, metal, metal oxide, metal nitride, metal alloy, polymers, ceramics, and combinations thereof.

10. A method according to claim 9 wherein the substrate is coated with a hydrophobic layer.

11. A method according to claim 10 wherein the hydrophobic layer is comprises hydrocarbyl groups.

12. A method according to claim 11 wherein the hydrocarbyl groups are selected from the group consisting of methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, cyclopropyl, cyclobutyl, cyclopentyl, methylcyclopentyl, cyclohexyl, methylcyclohexyl, benzyl, phenyl, o-tolyl, m-tolyl, p-tolyl, xylyl, vinyl, allyl, butenyl, cyclohexenyl, cyclooctenyl, cyclooctadienyl, and butynyl.

13. A method according to either of claims 1 or 2 wherein the solution is at a pH of about 3 to about 11.

14. A method according to claim 1 wherein the solution is aqueous based.

16. A method according to either of claims 1 or 2 wherein the population of carbon nanotubes is substantially free of metallic particles.

17. A method according to either of claims 1 or 2 wherein the population of carbon nanotubes are of uniform length.

18. A method according to either of claims 1 or 2 wherein the carbon nanotubes are single walled.

19. A method according to either of claims 1 or 2 wherein the carbon nanotubes are multi-walled.

20. A method according to either of claims 1 or 2 wherein the carbon nanotubes are semiconducting.

21. A method according to either of claims 1 or 2 wherein the carbon nanotubes are metallic.

22. A method according to either of claims 1 or 2 wherein the carbon nanotubes are singly dispersed.

23. A method according to either of claims 1 or 2 wherein the alignment is performed in the presence of an external magnetic or electromagnetic field.

25. A substrate according to claim 21 wherein the carbon nanotubes are associated with a charged dispersant.

26. A substrate comprising a population of aligned carbon nanotubes made by the process of either of claims 1 or 2.

30. A method according to claim 1 wherein the substrate is bounded on each edge by a metallic mass.

31. A method according to claim 30 wherein the metallic mass is comprised of materials selected from the group consisting of include Au, Ag, Ti, Pt, Pd, and Al.

2. A method for affixing a population of aligned carbon nanotubes on a substrate comprising:

a) providing a population of carbon nanotubes associated with a charged dispersant in solution;

b) depositing the solution of (a) on a substrate whereby the population of carbon nanotubes are aligned;

c) washing the substrate of (b) with a washing solvent; and

d) drying the washed substrate of (c) whereby the aligned carbon nanotubes are affixed to the substrate.

3. A method according to claim 2 wherein the solution of (b) remains on the substrate for a period of time ranging from about 15 s to about 60 min.

4. A method according to claim 2 wherein the drying of step (d) is accomplished by a stream of gas.

5. A method according to claim 2 wherein the washing solvent is aqueous based.

15. A method according to claim 2 wherein the dispersant is optionally removed from the carbon nanotube after the drying step of (d).

24. A substrate comprising a population of singly dispersed aligned carbon nanotubes.

27. A device comprising the substrate of claim 24 or 25.

28. A device according to claim 27 wherein the device is selected from the group consisting of a FET, FET based sensors, biosensors, carbon nanotube-based thin-film transistors, carbon nanotube -based optical devices, carbon nanotube-based magnetic devices, and lithographic-based carbon nanotube devices.

29. A method of obtaining a population of carbon nanotubes of uniform length comprising:

a) providing a population of carbon nanotubes associated with a charged dispersant in solution;

b) depositing the solution of (a) on a substrate whereby the population of CNT is aligned;

c) washing the substrate of (b) with a washing solvent;

d) drying the washed substrate of (c) whereby the aligned carbon nanotubes are affixed to the substrate; and

e) cutting the aligned carbon nanotubes affixed to the substrate to a defined length.