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Patent Issued for Functionalized Carbon Nanotube-Polymer Composites and Interactions with Radiation

September 3, 2014



By a News Reporter-Staff News Editor at Journal of Engineering -- According to news reporting originating from Alexandria, Virginia, by VerticalNews journalists, a patent by the inventors Barrera, Enrique V. (Houston, TX); Wilkins, Richard (College Station, TX); Shofner, Meisha (Watervliet, NY); Pulikkathara, Merlyn X. (Houston, TX); Vaidyanathan, Ranjii (Tuscon, AZ), filed on June 27, 2008, was published online on August 19, 2014.

The assignee for this patent, patent number 8809979, is William Marsh Rice University (Houston, TX).

Reporters obtained the following quote from the background information supplied by the inventors: "Since the discovery of carbon nanotubes in 1991 [Iijima, Nature, 354, pp. 56-58, 1991] and single-wall carbon nanotubes in 1993 [Iijima et al., Nature, 363, pp. 603-605, 1993; Bethune et al., Nature, 363, pp. 605-607, 1993], research has been conducted to exploit their unique mechanical, electrical, and thermal properties to create multifunctional composite materials [Barrera, J. of Mater., 52, pp. 38-42, 2000]. Previous research has shown that single-wall carbon nanotubes have the highest conductivity of any known fiber [Thess et al., Science, 273, pp. 483-487, 1996], a higher thermal conductivity than diamond [Hone et al., Appl. Phys. Lett., 77, pp. 666-668, 2000], and the highest stiffness of any known fiber [Yu et al., Phys. Rev. Lett., 84, pp. 5552-5555, 2000.

"Due to the provocative geometry and other remarkable properties of carbon nanotubes, they are of considerable interest to the aerospace and radiation communities [O'Rourke, J. Mater. Res., 17(10), 2002; Klimov et al., Physics Letters A, 226, pp. 244-252, 1997; Cui et al., Physics Letters A, 295, pp. 55-59, 2002; Salonen et al., Nuclear Instruments and Method in Physics Research B, 193, pp. 603-608, 2002]. The possibility of nanotubes serving as a storage medium for hydrogen [Ye et al., Appl. Phys. Lett, 74(16), pp. 2307-2309, 1999] is of particular interest for future spacecraft (e.g., fuel cells), and hydrogen-rich and other low atomic mass materials are believed to minimize radiation exposure in space environments [Wilson et al. (Eds.), Shielding Strategies for Human Space Exploration, NASA Conference publication 3360, pp. 17-28, 1997].

"Efforts to exploit carbon nanotube properties invariably rely on the ability to manipulate and homogeneously disperse carbon nanotubes in other host materials and/or matrices. Such manipulability can be facilitated by chemical modification of the carbon nanotube ends [Liu et al., Science, 280, pp. 1253-1256, 1998; Chen et al., Science, 282, pp. 95-98, 1998] and/or sidewalls [Bahr et al., J. Am. Chem. Soc., 123, pp. 6536-6542, 2001; Holzinger et al., Angew. Chem. Int. Ed., 40(21), pp. 4002-4005, 2001; Khabashesku et al., Acc. Chem. Res., 35, 1087-1095, 2002] of the carbon nanotubes. However, for many applications, such as those requiring highly conductive carbon nanotubes, the chemically modified or functionalized carbon nanotubes are unsuitable for the final product. Current techniques of chemically [Mickelson et al., J. Phys. Chem. B, 103, pp. 4318-4322, 1999] and thermally [Boul et al., Chem. Phys. Lett., 310, pp. 367-372, 1999; Bahr et al., J. Am. Chem. Soc., 123, pp. 6536-6542, 2001] defunctionalizing functionalized carbon nanotubes place severe restrictions on the types of other materials used in the various substrates, devices, and composite/blended materials originally comprising the functionalized carbon nanotubes."

In addition to obtaining background information on this patent, VerticalNews editors also obtained the inventors' summary information for this patent: "The present invention is directed toward methods of incorporating functionalized carbon nanotubes into host matrices to form composites and/or blends. In some embodiments, these host matrices are polymeric. In some embodiments, these functionalized carbon nanotubes are fluorinated. In some embodiments, functionalized carbon nanotubes are aligned within the composite and/or blend. The present invention is also directed toward methods of removing functional species (e.g., fluorine) from functionalized carbon nanotubes within such composites or blends via a radiative means.

"The present invention is also directed toward methods of radiatively-modifying carbon nanotube composites and/or blends. In some embodiments, this comprises a curing process. In some embodiments, this comprises a hardening process. In some embodiments, this leads to the formation of hybrid systems wherein carbon nanotubes are effectively crosslinked with a polymeric host material, wherein radiation effects the necessary crosslinking processes.

"In some embodiments, radiation interaction with functionalized carbon nanotube composites and/or blends leads to a defunctionalization of the functionalized carbon nanotubes. In some embodiments this defunctionalization is selective. In some embodiments, this defunctionalization converts the non-conductive functionalized carbon nanotubes into conductive non-functionalized carbon nanotubes.

"The present invention is directed to apparatuses comprising carbon nanotubes incorporated into, or housed within, a host matrix, and methods for making same. In some embodiments, the host matrix is polymeric. In some embodiments, conductive carbon nanotube channels exist within a block or film of material comprising nonconductive functionalized carbon nanotubes. In some embodiments, lithographic techniques are employed to generate said conductive carbon nanotube channels by, for example, lithographically defunctionalizing functionalized carbon nanotubes. In some embodiments, free-form extraction methods are used to generate three-dimensional arrays of conductive carbon nanotube channels within a composite or blended material. The present invention is also directed toward radiation sensors (e.g., dosimeters) comprising functionalized carbon nanotubes in a host material matrix.

"The present invention is directed toward multi-functional materials comprising functionalized carbon nanotubes and a host material, wherein said materials' function changes as it exposed to radiation over a period of time-continuously changing the properties of the composite and/or blend material.

"The present invention is also directed toward methods of recapturing or recycling nanotubes from composites and/or blends comprising functionalized carbon nanotubes and a polymer host matrix.

"The foregoing has outlined rather broadly the features of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention."

For more information, see this patent: Barrera, Enrique V.; Wilkins, Richard; Shofner, Meisha; Pulikkathara, Merlyn X.; Vaidyanathan, Ranjii. Functionalized Carbon Nanotube-Polymer Composites and Interactions with Radiation. U.S. Patent Number 8809979, filed June 27, 2008, and published online on August 19, 2014. Patent URL: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=8809979.PN.&OS=PN/8809979RS=PN/8809979

Keywords for this news article include: Fullerenes, Nanotechnology, Carbon Nanotubes, Emerging Technologies, William Marsh Rice University.

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Source: Journal of Engineering


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