Multilayer carbon nanotube films and method of making the same

• US 6,808,746 B1
• Filed: 01/11/2002
• Issued: 10/26/2004
• Est. Priority Date: 04/16/1999
• Status: Expired due to Fees

• Current Assignee: Commonwealth Scientific & Industrial Research Organisation (Commonwealth Of Australia As Represented By Department Of Industry, Innovation, Climate Change, Science, Research And Tertiary Education)
• Original Assignee: Commonwealth Scientific & Industrial Research Organisation (Commonwealth Of Australia As Represented By Department Of Industry, Innovation, Climate Change, Science, Research And Tertiary Education)
• Inventors: Dai, Liming, Huang, Shaoming
• Primary Examiner(s): Beck, Shrive P.
• Assistant Examiner(s): Markham, Wesley D.
• Application Number:
  US09/958,906
• Time in Patent Office: 1,019 Days
• Field of Search: 423/447.2, 423/455.R, 423/445.B, 423/447.1, 423/447.3, 216/83, 216/95, 216/97, 216/108, 216/109, 428/426, 428/432, 427/249.1, 427/249.4, 427/249.6, 427/255.11, 427/255.15, 427/255.23, 427/255.7, 427/289, 427/402, 427/903
• US Class Current: 427/249.1
• 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 2202/08 Aligned nanotubes
• CPC Class Codes: C01B 32/162 characterised by catalysts
• CPC Class Codes: D01F 9/127 by thermal decomposition of hydrocarbon gases or vapours or other carbon-containing compounds in the form of gas or vapour, e.g. carbon monoxide, alcohols
• CPC Class Codes: Y10S 427/102 Fullerene type base or coating
• CPC Class Codes: Y10S 977/778 within specified host or matrix material, e.g. nanocomposite films
• CPC Class Codes: Y10S 977/842 for carbon nanotubes or fullerenes
• CPC Class Codes: Y10S 977/896 Chemical synthesis, e.g. chemical bonding or breaking

Abstract

This invention relates to a process for the preparation of a substrate-free aligned nanotube film, comprising: (a) synthesizing a layer of aligned carbon nanotubes on a quartz glass substrate by pyrolysis of a carbon-containing material, in the presence of a suitable catalyst for nanotube formation; and (b) etching the quartz glass substrate at the nanotube/substrate interface to release the layer of aligned nanotubes from the substrate. The invention also provides a process for the preparation of a multilayer carbon nanotube film comprising depositing a substrate-free carbon nanotube film onto another nanotube film. Further, the invention provides a process for the preparation of a “hetero-structured” multilayer carbon nanotube film which includes one or more carbon nanotube layers together with layers of other materials, such as metal, semiconductor and polymer.

Claims

1. A process for the preparation of a substrate-free aligned nanotube film comprising:

(a) synthesizing a layer of aligned carbon nanotubes on a quartz glass substrate by pyrolysis of a carbon-containing material in the presence of a suitable catalyst for nanotube formation; and

(b) etching the quartz glass substrate at the nanotube/substrate interface to release said layer of aligned nanotubes from the substrate.

2. A process according to claim 1, wherein the carbon-containing material is selected from the group consisting of alkanes, alkenes, alkynes, aromatic hydrocarbons and their transition metal derivatives.

3. A process according to claim 1 wherein the catalyst includes a transition metal.

4. A process according to claim 3 wherein the catalyst is selected from the group consisting of Fe, Co, Al, Ni, Mn, Pd, Cr and alloys thereof in any suitable oxidation state.

5. A process according to claim 1 wherein the catalyst is incorporated into the substrate.

6. A process according to claim 1 wherein at least a portion of the catalyst is included in the carbon-containing material.

7. A process according to claim 6 wherein the carbon containing material which includes a catalyst is selected from the group consisting of Fe(II) phthalocyanine, Ni(II) phthalocyanine, ferrocene and nickel dicyclopentadiene.

8. A process according to claim 6 wherein sources of additional catalyst or additional carbon-containing material are provided in the pyrolysis step.

9. A process according to claim 1 wherein pyrolysis is performed within a temperature range of 800°

C. to 1100°

C.

10. A process according to claim 1 wherein step (a) is conducted in a flow-type pyrolysis reactor.

11. A process according to claim 10 wherein the aligned carbon nanotubes synthesized in the substrate have a packing density which is controlled by adjusting the flow rate of carbon-containing material through the reactor.

12. A process according to claim 1 wherein the layer of aligned carbon nanotubes is etched from the substrate by immersing or otherwise contacting the coated substrate with an aqueous solution of hydrofluoric acid.

13. A process for the preparation of a multilayer carbon nanotube film comprising:

(a) synthesizing a layer of aligned carbon nanotubes on a suitable substrate by pyrolysis of a carbon-containing material in the presence of a suitable catalyst for nanotube formation to provide a nanotube coated substrate; and

(b) synthesizing a further layer of aligned carbon nanotubes on said nanotube coated substrate by pyrolysis of a carbon-containing material in the presence of a suitable catalyst for nanotube formation,

wherein the further layer is synthesized employing conditions which are different to those employed in step (a).

14. A process according to claim 13 wherein the substrate is selected from the group consisting of quartz glass, mesoporous silica, nanoporous alumina, ceramic plates, glass, graphite and mica.

15. A process according to claim 14 wherein the substrate is quartz glass.

16. A process according to claim 13 wherein step (b) is repeated to provide three or more layers of carbon nanotubes.

17. A process for the preparation of a hetero-structured multilayer carbon nanotube film comprising:

(a) synthesizing a layer of aligned carbon nanotubes on a quartz glass substrate by pyrolysis of a carbon-containing material in the presence of a suitable catalyst for nanotube formation to provide a nanotube coated substrate;

(b) coating a layer of a pyrolysis resistant material onto said nanotube coated substrate to provide a hetero-structured multilayered substrate; and

(c) synthesizing a further layer of aligned carbon nanotubes on said hetero-structured multilayered substrate by pyrolysis of a carbon-containing material in the presence of a suitable catalyst for nanotube formation.

18. A process for the preparation of a substrate-free hetero-structured multilayer carbon nanotube film comprising:

(a) synthesizing a layer of aligned carbon nanotubes on a metal, metal oxide or semiconductor-coated quartz glass substrate by pyrolysis of a carbon-containing material in the presence of a suitable catalyst for nanotube formation; and

(b) etching said substrate at a quartz/metal, metal oxide or semiconductor coating surface to release said hetero-structured multilayer film from the quartz glass.

19. A process according to claim 18 wherein the quartz glass substrate is coated with a metal selected from the group consisting of Au, Pt, Cu, Cr, Ni, Fe, Co and Pd, a metal oxide selected from the group consisting of indium tin oxide (ITO), Al₂O₃, TiO₂ and MgO or a semiconductor material selected from the group consisting of gallium arsenide, aluminium arsenide, aluminium sulphide and gallium sulphide.

20. A process for the preparation of a hetero-structured multilayer carbon nanotube film comprising:

(a) synthesizing a layer of aligned carbon nanotubes on a quartz glass substrate by pyrolysis of a carbon-containing material in the presence of a suitable catalyst for nanotube formation;

(b) etching the quartz glass substrate at the nanotube/substrate interface to release said layer of aligned nanotubes from the substrate; and

(c) intercalating the released substrate-free aligned carbon nanotube film into a multilayer structure.