Aligned single-walled carbon nanotube aggregate, bulk aligned single-walled carbon nanotube aggregate, and powdered aligned single-walled carbon nanotube aggregate

• US 20110008617A1
• Filed: 12/30/2008
• Published: 01/13/2011
• Est. Priority Date: 07/27/2004
• Status: Active Grant

• Current Assignee: Don N. Futaba, Kenji Hata, Motoo Yumura, Sumio Iijima
• Original Assignee: Don N. Futaba, Kenji Hata, Motoo Yumura, Sumio Iijima
• Inventors: Hata, Kenji, Iijima, Sumio, Yumura, Motoo, Futaba, Don N.
• Granted Patent: US 8,178,203 B2
• Time in Patent Office: Days
• US Class Current: 428/341
• 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 2202/08 Aligned nanotubes
• CPC Class Codes: C01B 2202/32 Specific surface area
• CPC Class Codes: C01B 32/162 characterised by catalysts
• CPC Class Codes: Y10S 977/742 Carbon nanotubes, CNTs
• CPC Class Codes: Y10S 977/75 Single-walled
• CPC Class Codes: Y10T 428/273 of coating
• CPC Class Codes: Y10T 428/2918 including free carbon or carbide or therewith [not as steel]
• CPC Class Codes: Y10T 428/30 Self-sustaining carbon mass or layer with impregnant or other layer

Abstract

This invention provides an aligned single-walled CNT aggregate comprising a substrate, fine particles of iron catalyst with a density of 1×10¹¹ to 1×10¹⁴/cm² disposed on an alumina co-catalyst above the substrate, and a plurality of single-walled CNTs grown from the fine particles of the iron catalyst, in which the plurality of single-walled CNTs have a specific surface area of 600 m²/g to 2600 m²/g, and a weight density from 0.002 g/cm³ to 0.2 g/cm³, and the alignment degree which satisfies a few of specific conditions. This invention also provides a bulk aligned single-walled carbon nanotube aggregate and a powdered aligned single-walled carbon nanotube aggregate.

Claims

1. An aligned single-walled CNT aggregate comprising a substrate, fine particles of iron catalyst with a density of 1×

10¹¹ to 1×

10¹⁴/cm² disposed on an alumina co-catalyst above the substrate, and a plurality of single-walled CNTs grown from the fine particles of the iron catalyst, in which the plurality of single-walled CNTs have a specific surface area of 600 m²/g to 2600 m²/g, and a weight density from 0.002 g/cm³ to 0.2 g/cm³, and the alignment degree is defined by at least one of the following conditions;

(1) in a case where X-rays are incident from a first direction parallel to the longitudinal direction of CNT and a second direction perpendicular to the first direction to measure the X-ray diffraction intensity (θ

-2θ

method), a θ

angle and a reflection direction where the reflection intensity from the second direction is larger than the reflection intensity from the first direction are present, and a θ

angle and a reflection direction where the reflection intensity from the first direction is larger than the reflection intensity from the second direction are present,

(2) in a case where the X-ray refraction intensity is measured (Laue method) by 2-dimensional diffraction pattern images obtained by incidence of X-rays in the direction perpendicular to the longitudinal direction of CNT, a diffraction peak pattern showing the presence of the anisotropy appears, and

(3) Herman'"'"'s orientation factor is greater than 0 and smaller than 1 by using an X-ray diffraction intensity obtained by the θ

-2θ

method or the Laue method.

3. An aligned single-walled CNT aggregate in claim (1), in which a case where X-rays are incident from a first direction parallel to the longitudinal direction of CNT and a second direction perpendicular to the first direction to measure the X-ray diffraction intensity (θ

-2θ

method), the diffraction intensities for the (CP) and (002) diffraction peaks attributable to the packing between single-walled CNTs and the diffraction intensities for the (100) and (110) diffraction peaks attributable to the hexagonal carbon ring structure that constitute the single-walled CNT are different from each other for the first parallel and the second perpendicular incident directions.

2. An aligned single-walled CNT aggregate having a specific surface area from 600 m²/g to 2600 m²/g, and a weight density from 0.002 g/cm³ to 0.2 g/cm³, in which the alignment degree is defined by at least one of the following conditions:

(1) in a case where X-rays are incident from a first direction parallel to the longitudinal direction of CNT and a second direction perpendicular to the first direction to measure the X-ray diffraction intensity (θ

-2θ

method), a θ

angle and a reflection direction where the reflection intensity from the second direction is larger than the reflection intensity from the first direction are present, and a θ

angle and a reflection direction where the reflection intensity from the first direction is larger than the reflection intensity from the second direction are present,

(2) in a case where the X-ray refraction intensity is measured (Laue method) by 2-dimensional diffraction pattern images obtained by incidence of X-rays in the direction perpendicular to the longitudinal direction of CNT, a diffraction peak pattern showing the presence of the anisotropy appears,

(3) in a case where the Herman'"'"'s orientation factor is greater than 0 and smaller than 1 by using an X-ray diffraction intensity obtained by the θ

-2θ

method or the Laue method.

5. An aligned single-walled CNT aggregate in claim (2), in which a case where X-rays are incident from a first direction parallel to the longitudinal direction of CNT and a second direction perpendicular to the first direction to measure the X-ray diffraction intensity (θ

-2θ

method), the diffraction intensities for the (CP) and (002) diffraction peaks attributable to the packing between single-walled CNTs and the diffraction intensities for the (100) and (110) diffraction peaks attributable to the hexagonal carbon ring structure that constitute the single-walled CNT are different from each other for the first parallel and the second perpendicular incident directions.

4. A powdered aligned single-walled CNT aggregate having a specific surface area from 600 m²/g to 2600 m²/g, and a weight density from 0.0005 g/cm³ to 0.16 g/cm³, in which the alignment degree is defined by a value of Herman'"'"'s orientation factor that is more than 0 and less than 1 when calculated based on the intensity profile obtained from images obtained by fast fourier transformation of scanning electron microscopic images or atomic force microscopic images.