# US 8,540,959 B2 · Bulk cutting of carbon nanotubes using electron beam irradiation

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- Number: US 8,540,959 B2
- Document ID: US8540959B2
- Status: Granted
- Kind: B2
- Application number: 12/299,634
- Filed: 2007-05-07
- Published: 2010-11-11
- Granted: 2013-09-24
- Earliest claimed: 2006-05-05
- Assignees: William Marsh Rice University
- Applicants: Kirk J. Ziegler; Urs Rauwald; Robert H. Hauge; Howard K. Schmidt; W. Carter Kittrell; Zhenning Gu; Irene Morin Marek
- Inventors: Kirk J. Ziegler; Urs Rauwald; Robert H. Hauge; Howard K. Schmidt; Richard E. Smalley; W. Carter Kittrell; Zhenning Gu
- Web page: https://patentgrep.com/patent/US8540959B2

## CPC

- C01B 32/176: Cutting
- B82Y 30/00: Nanotechnology for materials or surface science, e.g. nanocomposites
- B82Y 40/00: Manufacture or treatment of nanostructures
- C01B 32/174: Derivatisation; Solubilisation; Dispersion in solvents
- C01B 2202/02: Single-walled nanotubes
- C01B 2202/28: Solid content in solvents
- 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

According to some embodiments, the present invention provides a method for attaining short carbon nanotubes utilizing electron beam irradiation, for example, of a carbon nanotube sample. The sample may be pretreated, for example by oxonation. The pretreatment may introduce defects to the sidewalls of the nanotubes. The method is shown to produces nanotubes with a distribution of lengths, with the majority of lengths shorter than 100 tun. Further, the median length of the nanotubes is between about 20 nm and about 100 nm.

## Claims

### Claim 1

A method for bulk cutting of carbon nanotubes, comprising:
(a) functionalizing the carbon nanotubes; and
(b) bulk irradiating the functionalized carbon nanotubes with an electron beam, wherein the irradiating occurs in an inert atmosphere, and wherein the irradiating causes the bulk cutting of the carbon nanotubes.

### Claim 2 (depends on 1)

The method according to claim 1, wherein the electron beam is a high energy electron beam.

### Claim 3 (depends on 2)

The method according to claim 2, wherein the energy of the high energy electron beam is at least about 3 MeV.

### Claim 4 (depends on 1)

The method according to claim 1, wherein (b) proceeds for at least about 5 min.

### Claim 5 (depends on 1)

The method according to claim 1, wherein (a) comprises functionalizing the carbon nanotubes with ozone.

### Claim 6 (depends on 5)

The method according to claim 5, wherein (a) comprises bubbling ozone through a suspension of the carbon nanotubes.

### Claim 7 (depends on 1)

The method according to claim 1, wherein the inert atmosphere comprises nitrogen gas.

### Claim 8 (depends on 1)

The method according to claim 1, wherein (a) includes introducing side-wall defects to the carbon nanotubes.

### Claim 9 (depends on 1)

The method according to claim 1, wherein the cut carbon nanotubes have a median length between about 20 nm and about 100 nm.

### Claim 10 (depends on 1)

The method according to claim 1, wherein a majority of the cut carbon nanotubes are shorter than about 100 nm.

### Claim 11 (depends on 1)

The method of claim 1, wherein the irradiating causes the bulk cutting of about 10 grams of carbon nanotubes.

### Claim 12

A method for bulk cutting of carbon nanotubes, comprising:
(a) functionalizing the sidewalls of the carbon nanotubes so as to damage the sidewalls; and
(b) bulk irradiating the functionalized carbon nanotubes with an electron beam, wherein the irradiating occurs under inert gas conditions, and wherein the irradiating causes the bulk cutting of the carbon nanotubes.

### Claim 13 (depends on 12)

The method according to claim 12, wherein (a) comprises functionalizing the carbon nanotubes with ozone.

### Claim 14 (depends on 13)

The method according to claim 13, wherein (a) comprises bubbling ozone through a suspension of the carbon nanotubes.

### Claim 15 (depends on 12)

The method according to claim 12, wherein the inert gas conditions comprise nitrogen atmosphere conditions.

### Claim 16 (depends on 12)

The method according to claim 12, wherein the method produces cut carbon nanotubes having a median length between about 20 nm and about 100 nm.

### Claim 17 (depends on 12)

The method according to claim 12, wherein a majority of the cut carbon nanotubes are shorter than about 100 nm.

### Claim 18 (depends on 12)

The method according to claim 12, wherein the electron beam is a high energy electron beam.

### Claim 19 (depends on 18)

The method according to claim 18, wherein the energy of the electron beam is at least about 3 MeV.

### Claim 20 (depends on 12)

The method of claim 12, wherein the irradiating causes the bulk cutting of about 10 grams of carbon nanotubes.