WO2008048238A2

WO2008048238A2 - Nanostructures featuring grafted polymers

Info

Publication number: WO2008048238A2
Application number: PCT/US2006/036019
Authority: WO
Inventors: Long Y. Chiang; Prashant A. Padmawar; Taizoon Canteenwala
Original assignee: University Of Massachusetts
Priority date: 2005-09-16
Filing date: 2006-09-15
Publication date: 2008-04-24
Also published as: WO2008048238A3

Abstract

The present invention generally provides a functionalized nanocomposite comprising a nanostructure having a surface on which at least one conductive polymer is grafted. The grafted polymer can be covalently bonded to the nanostructure surface such that the resulting nanocomposite can be highly durable. Examplary nanostructures include nanotubes such as carbon nanotubes or nanohorns. In one embodiment, the functionalized nanocomposite comprises a carbon nanotube on which polyaniline segments are covalently grafted. The invention also provides a convenient method for fabricating a nanocomposite. The method comprises providing a nanostructure such as a carbon nanotube and then covalently grafting at least one conductive polymer on the nanostructure surface. The invention also provides a device, conductive coating material and a composite material, which each feature a nanocomposite comprising a nanostructure with a surface onto which at least one conductive polymer is grafted.

Description

TITLE OF THE INVENTION NANOSTRUCTURES FEATURING GRAFTED POLYMERS

CROSS REFERENCE TO RELATED APPLICATIONS This application claims benefit of U.S. Provisional Application No. 60/718,142 filed September 16, 2005, the entire contents being incorporated herein by reference .

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT Part of the work leading to this invention was carried out with United States Government support provided under Grant No. S13187490100006 awarded by United States Army Research Office. Thus, the United States Government has certain rights in this invention.

BACKGROUND OF THE INVENTION

The fields of both nanoscience and nanotechnology generally concern the synthesis, fabrication and use of nanoelements and nanocomposites at atomic, molecular and supramolecular levels. The nanosize of these elements and composites offers significant potential for research and applications across the scientific disciplines including materials science, engineering, physics, chemistry, computer science and biology. For example, electrical processes and devices are expected to be developed based primarily on nanoelements and nanocomposites and their fabrication. Several other applications include developing nanocomposites for use in semiconductors, electronics, photonics, materials, optics and medicine .

One particular class of nanoelements or nanostructures that has garnered considerable interest consists of nanotubes such as single or multi-walled carbon nanotubes. A carbon nanotube has a diameter on the order of nanometers (nm) and can typically be up to several micrometers (μm) in length. Carbon nanotubes often feature an arrangement of interlocking carbon hexagons. As multi-walled nanostructures , these hexagons are concentrically- arranged. Carbon nanotubes tend to behave as semiconductors or metals depending on chirality and conjugative ring structures. To date, carbon nanotubes have been modified to feature different surface properties via solution or dry coating methods.

Such coating methods can typically involve coating a carbon nanotube with a conductive polymer (s). These conductive polymers can also exhibit electrical, optoelectrical and nonlinear optical properties similar to that of both semiconductors and inorganic metals. Conductive polymers are often associated with a charged state along with a counter ion such as an atom or molecule that can alter the physical and chemical properties of the polymer such as its conductivity. These counter ions are commonly referred to as dopants. The dopants do not usually replace or substitute for any of the polymer atoms. In general, conductive polymers can be synthesized as solids or colloidal dispersions. Both the electrical and optical properties of the polymer are affected by the synthesized form of the polymer. The nature or type of dopant associated with the polymer can also affect these properties such as by making the polymer either free-electron or hole-dominant. A widely used conductive polymer is polyaniline.

Conductive polymers that coat a nanotube tend to peel or can otherwise be easily removed during storage or use. Such conductive polymer coatings peel from the nanotube as they rely primarily on static charge-based attractions and van der Waals polar interaction forces between the coating and the nanotube surface. The removal of a conductive polymer coating can hinder the performance and processablity of the entire nanocomposite in a given application or field of use. The future development of such nanocomposites requires that the polymer strongly adhere to the nanostructure . The advancement of these nanocomposites may also require a convenient method that can be readily practiced for their fabrication. SUMMARY OF THE INVENTION

The present invention generally provides a functionalized nanocotnposite comprising a nanostructure having a surface on which at least one conductive polymer is grafted. The grafted polymer can be covalently bonded to the nanostructure surface such that the resulting nanocomposite is highly durable. In one embodiment, the functionalized nanocomposite can comprise a carbon nanotube on which polyaniline segments are covalently grafted. The invention also provides a convenient method for fabricating a functionalized nanocomposite . The method comprises providing a nanostructure such as a carbon nanotube or nanohorn and then covalently grafting a conductive polymer onto a surface of the nanostructure. The present invention also provides a device comprising a functionalized nanocomposite that can include a nanostructure having a surface on which a conductive polymer is grafted. A device of the invention may be used in electronic, photonic, optical, material, semiconductor and medical applications. For example, a functionalized nanocomposite of the invention can be blended with an adhesive such as a polyacrylate adhesive to yield a conductive coating material for patterned circuitry printing applications. In addition, a nanocomposite of the invention can be used for a composite material that may comprise, for example, polyamides or polyimides . Such a composite material can also be used for strengthened electronically uniform or rapid heat dispersion devices .

A functionalized nanocomposite of the present invention can also be particularly useful in the transfer of electrons or the distribution of charge, heat and energy. The conductive polymer for such a nanocomposite can be associated with a dopant that affects the electrical and optical properties of the polymer. A dopant may also be used in order to change the electrical and optical properties of the polymer for a given application. The invention also provides both a conductive coating and composite material. In one embodiment, the conductive coating and composite material comprises a nanocomposite that features a nanostructure having a surface on which a conductive polymer can be covalently grafted.

DESCRIPTION OF THE DRAWINGS

Other features and advantages of the present invention will be apparent from the detailed description of the invention that follows herein, taken in conjunction with the accompanying drawings of which:

Figure 1 is a partial representation of a nanocomposite of the invention in which a plurality of polyaniline segments are covalently grafted to a nanotube surface; Figure 2 are hydrogen (¹H) nuclear magnetic resonance (NMR) spectra of nanocomposites of the invention comprising tetraaniline or hexadecaaniline covalently grafted to carbon nanotubes as well as spectra of polymers tetraaniline and hexadecaaniline;

Figure 3 are ultraviolet-visible-near infrared (UV-vis-NIR) spectra of a carbon nanotube, hexadecaaniline and nanocomposite of the invention comprising hexadecaaniline covalently grafted to a carbon nanotube;

Figure 4 are tunneling electron micrographs (TEM) of a multi- walled carbon nanotube and hexadecaaniline covalently grafted to a multi-walled carbon nanotube to form a nanocomposite according to the invention; and

Figure 5 is a process flow sequence illustrating a preferred method of fabrication in accordance with the invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention generally provides a functionalized nanocomposite comprising a nanostructure having a surface (s) on which at least one conductive polymer is grafted. The grafted polymer can be covalently bonded to the nanostructure surface such that the resulting nanocomposite is extremely durable. Exemplary nanostructures can include nanotubes such as carbon nanotubes or nanohorns. In one embodiment, the functionalized nanocomposite comprises a carbon nanotube on which polyaniline segments can be grafted via covalent bonding. Polyaniline is known within the art to be a conjugated polymer. The electron conductivity of a polyaniline segment can also be significantly increased by partial cationic hydrogen doping of its quinonoid moieties . In one embodiment, when a conductive polymer segment (s) is covalently grafted onto a surface of a nanotube, the resulting nanocomposite has an electron conductivity that is very similar to the intrinsic conductivity of the underlying nanotube. In general , cationic hydrogen doping of the quinonoid moieties of a polyaniline segment increases the electron conductivity of the segment to a range from about 0.1 to 100 Siemens per second (S cm^'1) depending on, for example, the alkyl or arylsulfonic acid used. Exemplary arylsulfonic acids can include camphorsulfonic and dodecylphenylsulfonic acid. The underlying nanotube of the nanocomposite grafted to the cationic hydrogen doped polyaniline segment, nonetheless, retains its intrinsic conductivity, which is typically in a range from about 0.1 to 1.0 S cm^"1. By retaining the intrinsic conductivity of the unfunctionalized nanotube, the covalently grafted polymer segments can allow electron transport among domains of the nanocomposite to be more efficient without substantially compromising overall functionality.

The covalently surface grafted polymer of the nanocomposite of the invention does significantly affect several properties of the underlying nanostructure such as, for example, solubility, stability, processability and compatibility. As described above, the conductive polymer can also be covalently grafted on the surface (s) of a nanostructure in segments. In one embodiment, multiple polyaniline segments are grafted on a nanotube surface by a diazonium-based chemical reaction that generates a covalent bond. The bond occurs between the tip of each polymer segment and the nanostructure surface. The covalent bonding substantially prevents the grafted polymer from being peeled away from the nanotube during storage or use. Figure 1 is a partial representation of a nanocomposite of the invention in which a plurality of polyaniline segments are covalently grafted to the nanotube surface. Figure 1 illustrates a single-walled carbon nanotube 2 featuring carbon hexagons 4. Alternatively, a multi-walled nanotube (s) for a nanocomposite of the invention features concentrically arranged carbon hexagons. Moreover, Figure 1 also shows hexadecaaniline segments 6 that are covalently bonded on a surface of the carbon nanotube . A variety of processes are known for synthesizing such polymer segments. These synthesis processes can include, for example, coordination, cationic, anionic and electrochemical polymerization. Exemplary conductive polymers or polymer segments can also include the basic structure of polypyrrole, polyquinoline, polyparaphenylene, polyacetylene, polythiophene and poly (phenylene vinylene) . Such conductive polymers also can exhibit electroluminescent emission and electrochromic color properties as undoped conjugate polymers.

In one embodiment, the functionalized nanocomposites can be prepared by using single or multi-walled nanotubes. For example, carbon nanotubes can be commercially obtained having a narrow diameter from about 8 to 30 nm. Hexadecaaniline or any segments thereof can be covalently grafted to the surface of the nanotube. The resulting functionalized nanocomposite has been shown to be highly soluble in dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) based solvents. Generally, densely functionalized single and multi-walled nanotubes that are bonded to hexadecaaniline segments show a dark greenish brown color in DMF and DMSO based solvents .

The present invention also provides a convenient method for fabricating a functionalized nanocomposite. The method includes providing a nanostructure such as a carbon nanotube and then covalently grafting a conductive polymer on the surface of the nanostructure. Such a method (s) of fabrication generally can be carried out by obtaining or synthesizing a nanostructure (s) such as a carbon nanotube. _v The nanostructure can then be placed into a processing chamber with at least one class of an amine-group terminated monomer for the synthesis of a polymer, preferably, a conductive polymer or oligomer. An amine-group terminated monomer can be provided in the form of a mixture. The processing chamber can also be held under an inert gas blanket . The mass of the nanostructure within the chamber is typically greater than that of the amine-group terminated monomer mixture. For example, the nanostructure mass may be about ten times more than that of the amine-group terminated monomer mixture.

To the resulting solid mixture in the processing chamber is then added a salt such as isoamyl nitrite. The mixture can also be agitated at about 20⁰C to 100°C for several hours. The agitated mixture is then cooled to ambient temperatures, diluted with a solvent such as DMF and centrifuged to yield insoluble solids. The solvent can optionally be removed from the insoluble solids. The insoluble solids can also be repeatedly extracted and washed with the solvent in order to obtain a nearly colorless solvent layer. The solids obtained from the solvent layer can then be subjected to washings with additional solvents such as methanol acetonitrile, tetrahydrofuran (THF) , ether or any combination thereof. The resulting solids can then be dried by, for example, air. The solvent layer extracts from each of the washings can be combined and clarified.

By way of the addition of a solvent such as, for example, acetonitrile, blackish colored solids are precipitated that can then be repeatably dissolved within DMF and precipitated with acetonitrile. These precipitates can subsequently be washed with solvents such as THF and methanol, in sequence, and then dried by air so as to obtain a nanocomposite comprising a nanostructure with a polymer covalently grafted on the nanostructure surface. A person of ordinary skill within the art will be able to effect various changes or other modifications to the above method for fabricating one or more functionalized nanocomposites according to the invention.

The invention can further provide a device (s) comprising a nanocomposite that is operably associated therewith. Such a device can use the functionalized nanocomposite in applications that include, for example, semiconductors, electronics, photonics, optics, materials and medicine. Preferably, the device comprises a nanocomposite of the invention having a nanostructure onto which a conductive polymer has been covalently grafted. In addition, a nanocomposite of the invention can be blended with adhesives to yield a conductive coating material for use in patterned circuitry printing applications. Moreover, a nanocomposite of the invention can be used with a composite material that may comprise, for example, polyamides or polyimides. In one embodiment, such a composite material can be used for devices that include rapid heat dispersion, strengthened electronic uniform or any combination of these devices.

A functionalized nanocomposite of the invention can also be useful in the transfer of electrons or the distribution of charge, heat and energy. The conductive polymers or polymer segments for a nanocomposite of the invention can also be associated with a dopant that affects the electrical and optical properties of the polymer (s) for a particular type of application. Preferably, the underlying nanostructure (s) for a nanocomposite according to the invention featuring doped polymers or polymer segments may still retain its intrinsic conductivity, which can be within a range, as described above, from about 0.12 to 100 S cm^'1.

The invention also provides both a conductive coating and composite material. In one embodiment, the conductive coating and composite material comprises a nanocomposite of the invention that features a nanostructure having a surface on which a conductive polymer (s) or polymer segment (s) can be covalently grafted. For example, a conductive coating material comprises a functionalized nanocomposite of the present invention and one or more adhesives. Exemplary adhesives can comprise polyacrylate . The adhesive can be admixed, blended or otherwise introduced to the nanocomposite by conventional means such as, for example, through an agitative process. Preferably, such a conductive coating material can, for example, be employed in patterned circuitry printing.

In another embodiment, the invention provides for a composite material. The composite material can comprise a functionalized nanocomposite of the present invention and one or more polymers. Exemplary polymers can comprise polyamide, polyimide or any type of combination thereof. The polymer can be admixed, blended or otherwise introduced to the nanocomposite by conventional means such as, for example, through an agitative process. Preferably, such a composite material can, for example, be employed within a device for rapid heat dispersion, strengthened electronic uniform or any combination of these devices.

The examples herein are provided to illustrate advantages of the present invention that have not been previously described and to further assist a person of ordinary skill within the art with the fabrication of a functionalized nanocomposite according to the invention. The examples can include or incorporate any of the variations or embodiments of the invention described above. For example, conductive polymer segments of a nanocomposite may comprise a dopant to affect its inherent conductivity. The embodiments described above may also further each include or incorporate the variations of any or all other embodiments of the invention. The following examples are not intended in any way to otherwise limit the scope of the disclosure.

EXAMPLE I

Carbon nanotubes can be commercially obtained and placed into a round bottom flask with hexadecaaniline under nitrogen. The nanotubes may be placed in the flask in an amount of about 10 milligrams (mg) . Hexadecaaniline can also be placed in the flask in an amount of about 100 mg. To this solid mixture can then be added isoamyl nitrate at about 5 milliliters (ml) via a syringe. The mixture can be stirred at about 7O⁰C to 75°C for a period of about 24 hours with repetitive cycles of sonication for about 5 to 10 minutes at 2 hour intervals. The mixture can then be cooled to an ambient temperature, diluted with dimethylformamide (DMF) and centrifuged so as to afford insoluble solids after removal of the resulting dark brown DMF layer.

The solids can be repeatedly extracted and washed with DMF to obtain a substantially colorless DMF layer, which may then be followed by repeated washings using THF, acetonitrile, methanol and ether, respectively. DMF extracts from each of the repeated washings can be combined and passed through a celite paste so as to yield a clear brown DMF solution. Through the addition of, for example, acetonitrile, blackish colored solids can then be precipitated that may be repeatably dissolved within DMF and precipitated with acetonitrile, which provides an opportunity to remove unreacted hexadecaaniline from the yield. The precipitates can further be washed with THF and methanol, in sequence, and thereafter dried by air so as to obtain hexadecaaniline grafted carbon nanotubes as blackish solids that exhibit solubility within DMF and dimethyl sulfoxide (DMSO) . For a single-walled carbon nanotube, a more than six fold increase in weight can be obtained for a nanocomposite prepared by the above fabrication process. For example, about 65 mg of a functionalized nanocomposite can be obtained from about 10 mg of single-walled carbon nanotubes, with less than 2 mg of insoluble residues remaining. By comparison, multi-walled carbon nanotubes may be synthesized such that the resulting nanocomposites feature covalently grafted hexadecaaniline segments at yields from about 60 to 70 percent. These yields can be based on the amount of partially reacted multi-walled nanotubes recovered. For example, about 30 mg of a nanocomposite may be obtained from about 10 mg of multi-walled carbon nanotubes, with less than about 6 mg of insoluble residues remaining. The insoluble solids from fabricating a nanocomposite using single and multi-walled carbon nanotubes generally can consist of a mixture of less densely functionalized nanocomposites and non- reactive impurities from the carbon residues. Fourier transform infrared (FTIR) spectra from both soluble single and multi-walled carbon nanotubes covalently grafted with hexadecaaniline to form a nanocomposite of the invention showed strong bands corresponding to the optical adsorption of benzenoid and oxidized quinonoid ring vibrations at about 1,500 and 1,600 cm^'1, respectively, which is generally consistent with the presence of oligoaniline moieties. The FTIR spectra indicated a high functionalization ratio on the surface of the carbon nanotubes.

Figure 2 shows ¹H NMR spectra of nanocomposites according to the invention having a broad peak centered about 7 to 8 parts per million (ppm) . More particularly, Figure 2 shows a spectrum (a) of tetraaniline grafted to carbon nanotubes in DMSOd₆ featuring a broad peak at about 6.5 to 8.0 ppm. As shown, the spectrum

(a) appears significantly downfield with respect to the spectrum

(b) of only tetraaniline due primarily to a chemical shift of the aromatic protons in tetraaniline. Moreover, Figure 2 also shows a broad peak at about 6.5 to 8.5 ppm for hexadecaaniline grafted to carbon nanotubes so as to form a nanocomposite according to the invention. The spectrum (d) of hexadecaaniline grafted to nanotubes in DMSO-d₆ also appears downfield of the spectrum (c) for only hexadecaaniline due in part to aromatic protons thereof . Indeed, spectrum (b) and (c) also appear to be comparably shifted from spectrum (a) and (d) , respectively, based on aromatic protons of the tetraaniline and hexadecaaniline polymers.

With regard to both spectra (a) and (d) shown by Figure 2, the characteristic aromatic proton related peaks of tetraaniline and hexadecaaniline were absent, indicating the absence of these polymers in the covalently grafted nanocomposites . Moreover, in view of the understanding that carbon nanotubes do not feature aromatic protons, the proton related peaks of spectra (a) and (d) that are shown within a similar range as those for tetraaniline and hexadecaaniline, respectively, must arise from the polymers being grafted to the nanotubes . The results within Figure 2 and changes in solubility characteristics, described above, strongly demonstrate the attachment of tetraaniline and hexadecaaniline on carbon nanotubes so as to yield a nanocomposite according to the invention.

Figure 3 shows spectra of a carbon nanotube, hexadecaaniline and nanocomposite of the invention with hexadecaaniline covalently grafted to a carbon nanotube. For example, Figure 3 features the spectrum (c) of hexadecaaniline covalently grafted to nanotubes in DMF. _ The spectrum (c) in Figure 3 is also shown superimposed with spectra (a) and (b) for the carbon nanotube and hexadecaaniline, respectively. By superimposing the spectra, Figure 3 shows the presence of the characteristic optical absorption peaks relating to the hexadecaaniline polymer. In particular, the peak intensity ratio at wavelengths of 315 and 595 nm within spectrum (c) is different from that in spectrum (b) , confirming that the origin of such absorptions are primarily due to grafted hexadecaaniline moieties rather than merely the hexadecaaniline polymer. Furthermore, the loss of near infrared absorption peaks as the characteristic features of the carbon nanotube suggests electronic structure disruption. This disruption can be attributed to the covalent bonding of grafted hexadecaaniline and its modification of the nanotube surface. Various elemental analyses of the estimated nanocomposite density also confirmed the presence of about one hexadecaaniline chain per 30 to 35 nanotube carbons, which generally covers from about 5 to 6 interlocking carbon rings . Direct evidence of hexadecaaniline covalently grafted onto a carbon nanotube is shown by Figure 4. Figure 4 shows TEM of a multi-walled carbon nanotube as micrograph (a) . Moreover, Figure 4 also shows micrographs (b) and (c) of hexadecaaniline grafted onto a carbon nanotube. As shown, the grafting of hexadecaaniline is characterized by a comparison of the diameters L₂ and Li. Li relates to the diameter of the multi-walled carbon nanotube within micrograph (a) . By having hexadecaaniline grafted to a carbon nanotube as shown in micrographs (b) and (c) , the diameter of an exemplary nanocomposite of the invention is extended to L₂. The extended diameter of L₂ is about 15 to 20 nm longer than that of Li, which is consistent with the estimated molecular length of a hexadecaaniline segment. For example, the molecular length (s) of a hexadecaaniline segment is estimated to be about 9.8 nm such that the 15 to 20 nm extended diameter of L₂ would correlate with one segment covalently grafted onto each side of the multi-walled carbon nanotube .

Figure 5 illustrates a process sequence for fabricating a functionalized nanocomposite in accordance with a preferred embodiment of the invention. As described previously, the method involves providing a conductive polymer, covalently grafting or bonding the conductive polymer to a nanostructure such as a carbon nanotube or other structure described herein to form a functionalized nanocomposite. This can then be used to optionally form a material or device such as a conductive film or conductive adhesive. A circuit or other electronic or optical device can be made.

While the present invention has been described herein in conjunction with a preferred embodiment, a person of ordinary skill within the art, after reading the foregoing specification, will be able to effect changes, substitutions of equivalents and other alterations to, for example, the nanocomposites, methods, devices and materials set forth herein. Each embodiment described above can also have included or incorporated therewith such variations as disclosed with regard to any or all of the other embodiments. For example, a conductive polymer segment (s) of a functionalized nanocomposite may comprise a dopant to affect its inherent conductivity. It is therefore intended that protection granted by Letter Patent hereon be limited in breadth only by the definitions that are contained within the appended claims and any equivalents thereof .

Claims

CLAIMS What is claimed is :

1. A nanocomposite comprising: a nanostructure, the nanostructure having a surface; and a conductive polymer covalently attached to the surface of the nanostructure.

2. The nanocomposite of claim 1, wherein the nanostructure is functionalized structure such as a nanotube.

3. The nanocomposite of claim 2, wherein the nanotube is a single-walled nanotube.

4. The nanocomposite of claim 2, wherein the nanotube is a multi-walled nanotube.

5. The nanocomposite of claim 2 wherein the nanotube is a carbon nanotube .

6. The nanocomposite of claim 1, wherein the conductive polymer is a conjugated polymer.

7. The nanocomposite of claim 6, wherein the conjugated polymer is polyaniline.

8. The nanocomposite of claim 6, wherein the conductive polymer comprises a segment.

9. The nanocomposite of claim 1, wherein the conductive polymer comprises a dopant .

10. A method of fabricating a functionalized nanocomposite, the method comprising: providing a nanostructυre having a surface; and covalently grafting at least one conductive polymer to the surface of the nanostructure.

11. The functionalized nanocomposite of claim 10, wherein the nanostructure is a nanotube .

12. The functionalized nanocomposite of claim 11, wherein the nanotube is a single-walled nanotube.

13. The functionalized nanocomposite of claim 11, wherein the nanotube is a multi-walled nanotube.

14. The functionalized nanocomposite of claim 11 wherein the nanotube is a carbon nanotube.

15. The functionalized nanocomposite of claim 11, wherein the conductive polymer is a conjugated polymer.

16. The functionalized nanocomposite of claim 15, wherein the conjugated polymer is polyaniline.

17. The functionalized nanocomposite of claim 15 wherein the conductive polymer comprises a segment.

18. The functionalized nanocomposite of claim 11, wherein the conductive polymer comprises a dopant.

19. The method of claim 10 further comprising reading polyaniline segments using diazonium to bond a polymer to the nanostructure .

20. The method of claim 10 further comprising forming the conductive polymer with an electroluminescent or electrochromic property.

21. The method of claim 10 further comprising providing a nanostructure having an intrinsic conductivity in a range of 0.12 to 100 S cm^'1.

22. The method of claim 10 further comprising adding an adhesive to the functionalized nanocomposite.

23. The method of claim 10 further comprising adding a dopant to adjust the conductivity.

24. A device comprising: a functionalized nanocomposite associated with the device, the nanocomposite comprising: a nanostructure having a surface; and a conductive polymer covalently grafted to the surface of the nanostructure.

25. The functionalized nanocomposite of claim 24, wherein the nanostructure is a nanotube.

26. The functionalized nanocomposite of claim 25, wherein the nanotube is a single-walled nanotube.

27. The functionalized nanocomposite of claim 25, wherein the nanotube is a multi-walled nanotube.

28. The functionalized nanocomposite of claim 25, wherein the nanotube is a carbon nanotube .

29. The functionalized nanocomposite of claim 24, wherein the conductive polymer is a conjugated polymer.

30. The functionalized nanocomposite of claim 29, wherein the conjugated polymer is polyaniline.

31. The functionalized nanocomposite of claim 29, wherein the conductive polymer comprises a segment.

32. The functionalized nanocomposite of claim 24, wherein the conductive polymer comprises a dopant.

33. The device of claim 19, wherein the device is selected from the group consisting of a strengthened electronic uniform device, rapid heat dispersion device and any combination thereof .

34. The device of claim 24 wherein the device comprises a circuit, an optical device or a semiconductor device.

35. The device of claim 24 wherein the nanostructure has an intrinsic conductivity in a range of 0.1 to 1.0 S cm^"1.

36. A conductive coating material, the material comprising: a functionalized nanocomposite comprising: a nanostructure having a surface, and a conductive polymer covalently grafted to the surface of the nanostructure; and an adhesive.

37. The material of claim 36, wherein the adhesive comprises polyacrylate .

38. The material of claim 39, wherein the material is employed in patterned circuitry printing.

39. The material of claim 36, wherein the nanostructure is a nanotube or nanohorn.

40. The material of claim 36, wherein the conductive polymer is a conjugated polymer.

41. The material of claim 40, wherein the conjugated polymer is polyaniline.

42. The material of claim 36, wherein the conductive polymer comprises a dopant .

43. A composite material, the material comprising: a functionalized nanocomposite comprising a nanostructure having a surface, and a conductive polymer covalently grafted to the surface of the nanostructure; and a polymer.

44. The material of claim 43, wherein the polymer is selected from the group consisting of polyamide, polyimide and combinations thereof.

45. The material of claim 43, wherein the material is employed in a device selected from the group consisting of a strengthened electronic uniform device, rapid heat dispersion device and any combination thereof.

46. The material of claim 43, wherein the nanostructure is a nanotube or nanohorn.

47. The material of claim 43, wherein the conductive polymer is a conjugated polymer.

48. The material of claim 47, wherein the conjugated polymer is polyaniline.

49. The material of claim 48, wherein the conductive polymer comprises a dopant .

50. The material of claim 43 further comprising an optical or electrical device formed with the material.