SIMPLE METHOD FOR PRODUCING SUPERHYDROPHOBIC CARBON NANOTUBE ARRAY

• US 20110250376A1
• Filed: 04/06/2011
• Published: 10/13/2011
• Est. Priority Date: 04/07/2010
• Status: Active Grant

• Current Assignee: California Institute of Technology
• Original Assignee: California Institute of Technology
• Inventors: Aria, Adrianus I., Gharib, Morteza, Beizai, Masoud
• Granted Patent: US 9,115,424 B2
• Time in Patent Office: Days
• US Class Current: 428/97
• 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 32/158 Carbon nanotubes
• CPC Class Codes: C01B 32/159 single-walled
• CPC Class Codes: C01B 32/168 After-treatment
• CPC Class Codes: C01B 32/17 Purification
• CPC Class Codes: C23C 14/0605 Carbon
• CPC Class Codes: C23C 14/5853 Oxidation
• CPC Class Codes: C23C 16/26 Deposition of carbon only
• CPC Class Codes: C23C 16/56 After-treatment
• CPC Class Codes: Y10T 428/23993 Composition of pile or adhesive
• CPC Class Codes: Y10T 428/24802 Discontinuous or differential coating, impregnation or bond [e.g., artwork, printing, retouched photograph, etc.]

Abstract

The present invention provides efficient methods for producing a superhydrophobic carbon nanotube (CNT) array. The methods comprise providing a vertically aligned CNT array and performing vacuum pyrolysis on the CNT array to produce a superhydrophobic CNT array. These methods have several advantages over the prior art, such as operational simplicity and efficiency. The invention also relates to superhydrophobic CNT arrays.

Claims

1. A method for producing a superhydrophobic carbon nanotube (CNT) array, said method comprising:

providing a vertically aligned CNT array; and

performing vacuum pyrolysis on the CNT array to produce the superhydrophobic CNT array.

2. The method of claim 1, wherein the vacuum-pyrolysis step is performed under reduced pressure of about 0.5 torr to 10 torr.

3. The method of claim 2, wherein the vacuum-pyrolysis step is performed under reduced pressure of about 1 torr to 5 torr.

4. The method of claim 1, wherein the vacuum-pyrolysis step is performed at a reaction temperature of about 100°

C. to 500°

C.

5. The method of claim 4, wherein the vacuum-pyrolysis step is performed at a reaction temperature of about 125°

C. to 300°

C.

6. The method of claim 1, wherein the vacuum-pyrolysis step has a duration of about one hour to five hours.

7. The method of claim 1, wherein the vertically aligned CNT array is anchored on a surface.

8. The method of claim 1, wherein the vertically aligned CNT array is a member selected from the group consisting of a single-wall CNT array, a multiwall CNT array, and a mixture of a single-wall CNT array and a multiwall CNT array.

9. The method of claim 1, wherein the vertically aligned CNT array is synthesized using a synthesis technique that is selected from the group consisting of chemical vapor deposition (CVD), laser ablation, and arc discharge.

10. The method of claim 9, wherein the vertically aligned CNT array is provided by a CVD process.

11. The method of claim 10, wherein before the vacuum-pyrolysis step, the process further comprises an oxidation step to remove amorphous carbon.

12. The method of claim 10, wherein the CVD process is at least partially continuous with the vacuum-pyrolysis step.

13. The method of claim 10, the process further comprising removing contamination using the vacuum-pyrolysis step.

14. The method of claim 13, wherein an outer surface of the superhydrophobic CNT array is at least 85% free from oxygen-containing impurities.

15. The method of claim 14, wherein the outer surface of the CNT array is at least 95% free from oxygen-containing impurities.

16. The method of claim 1, wherein the static water droplet contact angle increases between about 5% to 45% after the vacuum-pyrolysis step.

17. The method of claim 1, wherein the water droplet roll-off angle decreases at least twofold.

18. The method of claim 1, wherein the static water droplet contact angle is between about 160°

to 180°

.

19. The method of claim 1, wherein the water droplet roll-off angle is from about 1°

to 5°

.

20. The superhydrophobic CNT array produced by the method of any of claims 1 to 19.