Process for the preparation of nanostructured materials

• US 20030185741A1
• Filed: 04/06/2002
• Published: 10/02/2003
• Est. Priority Date: 04/06/2001
• Status: Active Grant

• Current Assignee: Carnegie Mellon University
• Original Assignee: Carnegie Mellon University
• Inventors: Kowalewski, Tomasz, Tsarevsky, Nicolay V., Matyjaszewski, Krzysztof, Spanswick, James, Lambeth, David N.
• Granted Patent: US 7,056,455 B2
• Time in Patent Office: Days
• US Class Current: 423/445R
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: B82Y 15/00 Nanotechnology for interacting, sensing or actuating, e.g. quantum dots as markers in protein assays or molecular motors
• 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 3/0021 Carbon, e.g. active carbon, carbon nanotubes, fullerenes; Treatment thereof
• CPC Class Codes: C01B 32/05 Preparation or purification of carbon not covered by groups C01B32/15, C01B32/20, C01B32/25, C01B32/30
• CPC Class Codes: C01B 32/162 characterised by catalysts
• CPC Class Codes: C04B 2111/00801 Membranes; Diaphragms
• CPC Class Codes: C04B 2111/0081 as catalysts or catalyst carriers
• CPC Class Codes: C04B 2111/00827 Photocatalysts; materials containing photocatalysts to avoid staining by air pollutants C04B2111/2061
• CPC Class Codes: C04B 2111/00844 for electronic applications
• CPC Class Codes: C04B 2111/00853 in electrochemical cells or batteries, e.g. fuel cells
• CPC Class Codes: C04B 2235/5288 Carbon nanotubes
• CPC Class Codes: C04B 35/524 obtained from polymer precursors, e.g. glass-like carbon material
• CPC Class Codes: C04B 35/63424 Polyacrylates; Polymethacrylates
• CPC Class Codes: C04B 35/63444 Nitrogen-containing polymers, e.g. polyacrylamides, polyacrylonitriles, polyvinylpyrrolidone [PVP], polyethylenimine [PEI]
• CPC Class Codes: C04B 38/0022 obtained by a chemical conversion or reaction other than those relating to the setting or hardening of cement-like material or to the formation of a sol or a gel, e.g. by carbonising or pyrolysing preformed cellular materials based on polymers, organo-metallic or organo-silicon precursors
• CPC Class Codes: C04B 38/0054 the pores being microsized or nanosized
• CPC Class Codes: D01F 9/14 by decomposition of organic filaments
• CPC Class Codes: G03F 7/0002 Lithographic processes using patterning methods other than those involving the exposure to radiation, e.g. by stamping
• CPC Class Codes: G11C 2213/81 : Array wherein the array conductors, e.g. word lines, bit lines, are made of nanowires
• CPC Class Codes: H01G 11/36 : Nanostructures, e.g. nanofibres, nanotubes or fullerenes
• CPC Class Codes: H01G 11/86 : specially adapted for electrodes carbonisation or activation of carbon for the manufacture of electrodes H01G11/34
• CPC Class Codes: H01M 4/58 : of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
• CPC Class Codes: H01M 4/583 : Carbonaceous material, e.g. graphite-intercalation compounds or CFx
• CPC Class Codes: H01M 4/96 : Carbon-based electrodes
• CPC Class Codes: Y02E 60/10 : Energy storage using batteries
• CPC Class Codes: Y02E 60/13 : Energy storage using capacitors
• CPC Class Codes: Y02E 60/32 : Hydrogen storage
• CPC Class Codes: Y02E 60/50 : Fuel cells
• CPC Class Codes: Y10S 521/918 : Physical aftertreatment of a cellular product
• CPC Class Codes: Y10S 521/919 : Sintered product

Abstract

The present invention comprises a novel process for the preparation of carbon based structured materials with controlled topology, morphology and functionality. The nanostructured materials are prepared by controlled carbonization, or pyrolysis, of precursors comprising phase separated copolymers. The precursor materials are selected to phase separate and self organize in bulk, in solution, in the presence of phase selective solvents, at surfaces, interfaces or during fabrication, into articles, fibers or films exhibiting well-defined, self-organized morphology or precursors of well-defined, self-organized, bi- or tri-phasic morphology. Compositional control over the (co)polymers provides control over the structure of the phase separated precursor whose organization therein dictates the nanostructure of the material obtained after carbonization or pyrolysis, wherein each dimension of the formed structure can be predetermined. When the precursor morphology is selected to comprise cylindrical domains this procedure additionally allows for the direct formation of two dimensional nanowire grids or arrays of oriented nanostructures on surfaces. When these nanowire grids or arrays are perpendicularly oriented to the surface applications include field emitters, high surface area electrodes, electronic devices such as diodes and transistors, tools for AMF tips and elements of molecular electronics. When the first nanostructured morphology is selected to form cylinders parallel to the surface then nanowire arrays are formed after pyrolysis. When the composition of the first nanostructured morphology is selected to comprise a continuous precursor matrix then a continuous carbon based nanostructured material is formed. The internal structure of the carbon based material can be selected to comprise perpendicular pores or an interconnected array of pores. The carbon based structures can additionally find application in photovoltaics, supercapacitors, batteries, fuel cells, computer memory, carbon electrodes, carbon foams, actuators and hydrogen storage.

Claims

1. A process for the preparation of nanostructured materials, comprising:

pyrolyzing a precursor, wherein the precursor comprises a phase-separated copolymer.

2. The process for the preparation of nanostructured materials of claim 1, wherein the precursor further comprises:

a carbon precursor phase and a sacrificial phase.

3. The process for the preparation of nanostructured materials of claim 1, wherein the phase separated copolymer comprises at least one precursor material and at lease one sacrificial material.

4. The process for the preparation of nanostructured materials of claim 3, wherein pyrolyzing the precursor comprises carbonizing the precursor material and pyrolyzing the sacrificial material.

5. The process for preparation of nanostructured materials of claim 3, wherein the precursor material comprises monomeric units derived from acrylonitrile based monomers.

6. The process for the preparation of nanostructured materials of claim 3, wherein the precursor comprises at least one phase of primarily precursor material and at least on phase of primarily sacrificial material.

7. The process for the preparation of nanostructured materials of claim 6, wherein pyrolyzing the precursor comprises heating the precursor to a temperature between 1000°

F. and 1400°

F.

8. The process for the preparation of nanostructured materials of claim 7, wherein heating the precursor is conducted in the absence of oxygen.

9. The process for preparation of nanostructured materials of claims 5, wherein the sacrificial material comprises monomeric units derived from butyl acrylate monomers.

10. The process for the preparation of nanostructured materials of claim 1, further comprising:

preparing a film comprising the precursor; and

heating the film.

11. The process for the preparation of nanostructured materials of claim 1, further comprising:

providing conditions for phase separating a copolymer.

12. The process for the preparation of nanostructured materials of claim 11, wherein the conditions for phase separating a polymer comprise at least one of phase separating the polymer in bulk, in solution, in the presence of a phase selective solvent, at an interface, on a surface, in the polymerization medium, under vacuum, at pressures above atmospheric pressure, in the absence of oxygen and by annealing.

13. The process for the preparation of nanostructured materials of claim 1, wherein the copolymer forms a phase separated morphology.

14. The process for the preparation of nanostructured materials of claim 13, wherein the phase separated morphology is well defined.

15. The process for the preparation on nanostructured material of claim 14, wherein one phase of the phase separated morphology comprises nanostructured domains.

16. The process for the preparation of nanostructured materials of claim 13, wherein the phase separate morphology comprises at least two phases.

17. The process for the preparation of nanostructured materials of claim 16, wherein at least one of the phases comprises cylindrical domains.

18. The process for the preparation of nanostructured materials of claim 16, wherein the phase separated morphology comprises at least one phase having a morphology selected from the group consisting of spherical, lamellar, cylindrical, and gyroid.

19. The process for the preparation of nanostructured materials of claim 16, further comprising:

annealing the precursor in the absence of oxygen.

20. The process for the preparation of nanostructured materials of claim 19, wherein the annealing the precursor reduces the surface energy of the phase separated morphology.

21. The process for the preparation of nanostructured materials of claim 16, further comprising:

doping at least one phase of the phase separated morphology.

22. The process for the preparation of nanostructured materials of claim 21, wherein the phase separated polymer material comprises a stabilized mixture of copolymers and homopolymers.

23. The process for the preparation of nanostructured materials of claim 21, wherein the phase separated polymer material comprises a stabilized mixture of homopolymers.

24. The process for the preparation of nanostructured materials of claim 21, wherein the doping at least one phase of the phase separated morphology comprises doping with at least one material comprising at least one of Si, S, P, B, and a transition metal.

25. The process for the preparation of nanostructured material of claim 16, wherein at least one phase comprises a precursor for a catalyst.

26. The process for the preparation of nanostructured material of claim 25, wherein the precursor for a catalyst is different than the precursor for the nanostructured material.

27. The process for the preparation of nanostructured materials of claim 16, wherein one phase comprises at least one N atom and another phase comprises at least one B atom.

28. The process for the preparation of nanostructured materials of claim 13, wherein the phase separate morphology comprises at least one continuous phase.

29. The process for the preparation of nanostructured materials of claim 13, wherein the phase separate morphology comprises at least two continuous phases.

30. The process for the preparation of nanostructured materials of claim 13, wherein the phase separate morphology comprises three phases.

31. The process for the preparation of nanostructured materials of claim 30, wherein the phase separate morphology comprises at least one continuous phase.

32. The process for the preparation of nanostructured materials of claim 31, wherein the phase separate morphology comprises at least two continuous phases.

33. The process for the preparation of nanostructured materials of claim 13, further comprising sabilizing the phase separated morphology by heating in the presence of oxygen.

34. The process for the preparation of nanostructured materials of claim 1, wherein the phase separated copolymer comprises at least one copolymer selected from the group comprising an AB block copolymers, an ABA block copolymer, an ABC block copolymer, multiblock copolymers, a graft copolymer, symmetrical and asymetrical star copolymers, a multiarm block copolymer, (hyper)branched copolymers, brush copolymers, and a blend of polymers.

35. The process for the preparation of nanostructured materials of claim 34, wherein the phase separated copolymer comprises acrylonitrile monomer units in at least one polymer segments.

36. The process for the preparation of nanostructured materials of claim 34, wherein the phase separated copolymer comprises a gradient acrylonitrile copolymer segment.

37. The process for the preparation of nanostructured materials of claim 1, further comprising:

annealing the phase separated copolymer material; and

stabilizing the phase separated copolymer material.

38. The process for the preparation of nanostructured materials of claim 37, wherein the stabilizing the phase separated copolymer is performed by heating the phase separated copolymer in the presence of oxygen.

39. The process for the preparation of nanostructured materials of claim 1, wherein the phase separated copolymer comprises free radically (co)polymerizable monomers.

40. The process for the preparation of nanostructured materials of claim 39, wherein the free radically copolymerizable monomers comprise a functional group.

41. The process for the preparation of nanostructured materials of claim 40, wherein the functional group comprises a transition metal.

42. The process for the preparation of nanostructured materials of claim 39, wherein the free radically (co)polymerizable monomers comprise at least one of styrenes, (meth)acrylates and (meth)acrylonitrile.

43. The process for the preparation of nanostructured materials of claim 1, further comprising:

forming a nanostructured material.

44. The process for the preparation of nanostructured materials of claim 43, wherein the properties of the nanostructured material are affected by the molecular weight of the blocks of the phase separated copolymer material and the conditions of the carbonizing.

45. The process for the preparation of nanostructured materials of claim 43, wherein the nanostructured material comprises a two-dimensional array of carbon nanostructures.

46. The process for the preparation of nanostructured materials of claim 1, further comprising:

coating a surface with a film of a precursor comprising a phase separable copolymer.

47. The process for the preparation on nanostructured material of claim 46, wherein the nanostructured material is formed on the surface;

and further comprising;

removing the nanostructured material from the surface.

48. The process for the preparation of nanostructured materials of claim 46, further comprising:

forming a two dimensional array of carbon nanostructures on the surface.

49. The process for the preparation of nanostructured material of claim 48, further comprising:

forming atomic force microscopy tips from the two dimensional array of carbon nanostructures on the surface.

50. The process for the preparation of nanostructured material of claim 48, further comprising:

functionalizing the tips of the carbon nanostructures.

51. The process for the preparation of nanostructured material of claim 50, wherein the tips are functionalized as biological probes.

52. The process for the preparation on nanostructured material of claim 48, wherein the two dimensional array is used as a pattern.

53. The process for the preparation on nanostructured material of claim 48, wherein the two dimensional array is used to organize at least one of salts, dyes and responsive organic materials on the surface.

54. The process for the preparation of nanostructured materials of claim 48, wherein the carbon nanostructures are oriented perpendicular to the surface.

55. The process for the preparation of nanostructured materials of claim 54, wherein an aspect ratio of the carbon nanostructures is influenced by the thickness of the coating of the surface.

56. The process for the preparation of nanostructured materials of claim 48, wherein the carbon nanostructures are oriented substantially parallel to the surface.

57. The process for the preparation of nanostructured material of claim 48, wherein the surface is on a substrate and the two dimensional array of carbon nanostructures increases the thermal stability of the substrate.

58. The process for the preparation of nanostructured material of claim 48, further comprising:

infusing the two dimensional array of carbon nanostructures with a reactive species.

59. The process for the preparation of nanostructured material of claim 58, wherein the infused reactive species form an electrolyte.

60. The process for the preparation of nanostructured material of claim 58, further comprising:

adding an ionic species to form an electrolyte.

61. The process for the preparation of nanostructured material of claim 58, wherein the reactive species is comprises at least one of organic monomers and inorganic monomers.

62. The process for the preparation of nanostructured material of claim 61, wherein the reactive species comprises organic monomers.

63. The process for the preparation of nanostructured material of claim 61, wherein the reactive species comprises inorganic monomers.

64. The process for the preparation of nanostructured material of claim 58, wherein the reactive species are polymerizable.

65. The process for the preparation of nanostructured material of claim 64, further comprising:

polymerizing the reactive species.

66. The process for the preparation of nanostructured material of claim 64, wherein the surface is on a substrate and wherein polymerizing the reactive species forms a nanocomposite coating on the substrate.

67. The process for the preparation of nanostructured material of claim 66, further comprising:

removing the nanocomposite coating from the surface forming free standing structure.

68. The process for the preparation of nanostructured material of claim 58, the reactive species comprise an insulator.

69. The process for the preparation of nanostructured materials of claim 46, wherein the surface is on a substrate, and the surface is covered by the film.

70. The process for the preparation of nanostructured materials of claim 46, wherein the surface is on a substrate, and the surface is partially covered by the film.

71. The process for the preparation of nanostructured materials of claim 70, wherein the partial coating comprises a pattern.

72. The process for the preparation of nanostructured materials of claim 46, wherein the morphology of the precursor is influenced by the surface of the substrate.

73. The process for the preparation of nanostructured materials of claim 72, wherein the surface is on a substrate comprising a crystalline material.

74. The process for the preparation of nanostructured materials of claim 73, wherein the orientation of crystalline material influences the morphology of the precursor.

75. The process for the preparation of nanostructured materials of claim 46, wherein the surface is coated with one of an ultra thin film, a thin film, or a thick film of the phase separable material.

76. The process for the preparation of nanostructured materials of claim 75, further comprising:

annealing the phase separable material to form a phase separated material.

77. The process for the preparation of nanostructured materials of claim 76, wherein annealing the phase separable material is conducted in the absence of oxygen.

78. The process for the preparation of nanostructured materials of claim 77, wherein anneal the phase separated polymer material is conducted in a controlled environment or under reduced pressure.

79. The process for the preparation of nanostructured materials of claim 76, further comprising:

heating the phase separable material to stabilize the phase separation.

80. The process for the preparation of nanostructured materials of claim 79, wherein heating the phase separable material is conducted in the presence of oxygen.

81. The process for the preparation of nanostructured materials of claim 1, wherein the nanostructured material comprises at least one of carbon nanofibers, carbon nanotubes, and carbon nanocylinders.

82. The process for the preparation of nanostructured materials of claim 1, wherein the nanostructured material comprises a continuous phase with substantially uniform, discrete porosity.

83. The process for the preparation of nanostructured materials of claim 1, wherein the nanostructured material comprises a continuous phase with interconnected porosity.

84. The process for the preparation of nanostructured materials of claim 1, wherein the nanostructured materials comprise carbon nanostructures having adsorptive capacity.

85. The process for the preparation of nanostructured material of claim 84, wherein the carbon nanostructures function as an electronic tongue.

86. The process for the preparation of nanostructured materials of claim 1, wherein the nanostructured materials comprise carbides.

87. The process for the preparation of nanostructured materials of claim 1, wherein the phase separated copolymer material comprises a block copolymer having a block derived from at least two different monomer units.

88. The process for the preparation of nanostructured materials of claim 87, wherein at least one of the two different monomer units form a core in the phase separated polymer material.

89. The process for the preparation of nanostructured materials of claim 87, wherein the block derived from at least two different monomer units is a gradient copolymer block.

90. The process for the preparation of nanostructured materials of claim 1, wherein the phase separated copolymer material comprises a transition metal.

91. A high surface area carbon nanostructured material produced from the process of claim 90.

92. The process for the preparation of nanostructured materials of claim 90, wherein the transition metal is a complexed transition metal.

93. The process for the preparation of nanostructured materials of claim 92, wherein the nanostructured material comprises a catalyst.

94. The process for the preparation of nanostructured materials of claim 1, wherein the nanostructured material comprises at least one of a mesopore and a macropore.

95. The process for the preparation of nanostructured material of claim 1, further comprising:

forming a three dimensional array of nanostructures, wherein the nanostructures is at least one of a membrane, a granule, and a structure comprising at least one of nanopores, mesopores and macropores.

96. The process for the preparation of nanostructured material of claim 1, wherein the nanostructured material are for the manufacture of photovoltaic cells, supercapacitors, batteries, fuel cells, computer memory, carbon electrodes, carbon foams, actuators and materials for hydrogen storage.

97. The process for the preparation of nanostructured material of claim 1, further comprising:

contacting the nanostructured material with a transition metal; and

pyrolyzing the nanostructured material with the transition metal to form a carbide.

98. The process for the preparation of nanostructured material of claim 97, wherein the transition metal is a transition metal salt.

99. The process for the preparation of nanostructured material of claim 1, further comprising:

forming a carbon nanostructured material; and

modifying the composition of the carbon nanostructured material by electrochemistry.

106. The process for the preparation of nanostructured materials of claim 1, wherein the nanostructured material comprises two dimensional array of carbon nanotubes.

107. The process for the preparation of nanostructured materials of claim 106, wherein at least a portion of the nanostructured material is incorporated in flat panel display.

108. The process of claim 1, wherein the nanostructured material is used for supercapacitor electrodes.

115. A high surface area carbon nanostructured material produced from the process of claim 1.

100. A process for the preparation of a reinforced macrofiber, comprising:

preparing a reinforced macrofiber precursor by combining a macrofiber

precursor and a nanostructure precursor; and

pyrolyzing the reinforced macrofiber precursor.

101. The process for the preparation of a reinforced macrofiber of claim 100, wherein both the reinforced macrofiber precursor and the nanostructure precursor are carbon precursors.

102. The process for the preparation of a reinforced macrofiber of claim 100, further comprising:

orienting the nanostructure precursor relative to the axis of the reinforced macrofiber.

103. The process for the preparation of a reinforced macrofiber of claim 102, wherein orienting the nanostructure precursor relative to the axis of the reinforced macrofiber comprises at least one of spinning, twisting, and drawing.

104. The process for the preparation of a reinforced macrofiber of claim 102, wherein the nanostructure precursor are substantially either parallel to the axis of the macrofiber precursor, perpendicular to the macrofiber precursor or at an angle to the macrofiber precursor.

105. A reinforced fiber comprising carbon nanotubes.

109. A supercapacitor electrode, comprising:

a nano-porous structure having a high effective surface area.

110. The supercapacitor electrode of claim 109, further comprising:

a uniform distribution of pore; and

a uniform pore diameter

111. A supercapacitor electrode produced from a process, comprising:

pyrolyzing a precursor to form a carbon based nanostructured material comprising a high effective surface area, uniform pore density and uniform pore diameter, wherein the precursor comprises a phase separated copolymer.

112. The supercapacitor electrode produced from a process of claim 111, wherein the supercapacitor electrode is effective for use in applications requiring high frequency switching.

113. The supercapacitor electrode produced from a process of claim 111, wherein the supercapacitor electrode comprises a two dimensional array of closely packed carbon nanotubes.

114. The supercapacitor electrode produced from a process of claim 111, wherein the supercapacitor electrode further comprises a solid material between the closely packed carbon nanotubes comprises a second solid phase.

116. A method of preparing a nanopattern of a transition metal on a substrate, comprising:

forming an array of carbon nanostructures on the substrate;

infusing the array with a transition metal; and

pyrolyzing the array.

117. The method of claim 116, wherein the transition metal forms a semiconductor on the substrate.

118. The method of claim 116, wherein the transition metal forms a conductor on the substrate.