# US 7,611,651 B2 · Method for manufacturing carbon nanotubes with uniform length

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- Number: US 7,611,651 B2
- Document ID: US7611651B2
- Status: Granted
- Kind: B2
- Application number: 11/025,160
- Filed: 2005-04-21
- Published: 2006-03-16
- Granted: 2009-11-03
- Earliest claimed: 2004-05-13
- Assignees: Tsinghua University; Hon Hai Precision Industry Co., Ltd.
- Inventors: Hua Huang; Chang-Hong Liu; Shou-Shan Fan
- Web page: https://patentgrep.com/patent/US7611651B2

## CPC

- C01B 32/168: After-treatment
- B82Y 30/00: Nanotechnology for materials or surface science, e.g. nanocomposites
- B82Y 40/00: Manufacture or treatment of nanostructures
- C01B 32/162: characterised by catalysts
- C01B 2202/08: Aligned nanotubes
- C01B 2202/34: Length
- C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C}
- B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES

## Abstract

A method for manufacturing carbon nanotubes with a uniform length includes the steps of: (a) forming an array of carbon nanotubes on a substrate; (b) submerging the carbon nanotubes in liquid macromolecular material; (c) solidifying the liquid macromolecular material; (d) cutting the solidified liquid macromolecular material; and (e) removing the macromolecular material to obtain the carbon nanotubes with a uniform length. The method is simple, and carbon nanotubes with a desired length can be easily obtained. The length of the carbon nanotubes can be precisely controlled. Furthermore, each carbon nanotube is open at both ends thereof.

## Claims

### Claim 1

A method for manufacturing carbon nanotubes with a uniform length, the method comprising the steps of:
(a) forming an array of carbon nanotubes on a substrate;
(b) submerging the carbon nanotubes in a liquid macromolecular material;
(c) solidifying the liquid macromolecular material;
(d) cutting the solidified macromolecular material; and
(e) removing the macromolecular material to thereby obtain the carbon nanotubes with a uniform length;
wherein step (d) further comprises the step of peeling the solidified macromolecular material with the carbon nanotubes secured therein off the substrate before cutting.

### Claim 2 (depends on 1)

The method as claimed in claim 1, wherein step (d) comprises the steps of:
(d1) cutting the solidified macromolecular material in a direction perpendicular to long axes of the carbon nanotubes, whereby each carbon nanotube is open at one end thereof; and
(d2) cutting the macromolecular material in the same direction according to a predetermined thickness, whereby each carbon nanotube is open at the other end thereof

### Claim 3 (depends on 1)

The method as claimed in claim 1, wherein step (d) is performed by a cutter.

### Claim 4 (depends on 1)

The method as claimed in claim 1, wherein a viscosity of the liquid macromolecular material is below 200 centipoises.

### Claim 5 (depends on 1)

The method as claimed in claim 1, wherein the liquid macromolecular material is liquid paraffin.

### Claim 6 (depends on 5)

The method as claimed in claim 5, wherein in step (e) xylene is used to remove the paraffin.

### Claim 7 (depends on 1)

The method as claimed in claim 1, wherein step (a) is performed by way of thermal chemical vapor deposition or plasma enhanced chemical vapor deposition.

### Claim 8 (depends on 1)

The method as claimed in claim 1, wherein the uniform length of the carbon nanotubes is in the range from 1 to 1000 micrometers.

### Claim 9 (depends on 1)

The methods as claimed in claim 1, wherein in step (b), the carbon nanotubes with the substrate are immersed in a container of liquid macromolecular material.

### Claim 10 (depends on 9)

The method as claimed in claim 9, wherein after step (b), the carbon nanotubes with the substrate are taken out of the container.

### Claim 11 (depends on 1)

The method as claimed in claim 1, wherein the substrate has a substantially macroscopic planar surface.

### Claim 12 (depends on 1)

The method as claimed in claim 1, wherein a surface of the substrate has a plurality of micropores.

### Claim 13 (depends on 12)

The method as claimed in claim 12, wherein diameter of the micropores is about 3 nanometers.

### Claim 14 (depends on 13)

The method as claimed in claim 13, wherein the length of the carbon nanotubes is longer than the diameter of the micropores.