Browsing by Author "Marek, Irene Morin"

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    Fibers comprised of epitaxially grown single-wall carbon nanotubes- and a method for added catalyst and continuous growth at the tip
    (2010-06-01) Kittrell, Carter W.; Wang, Yuhuang; Kim, Myung Jong; Hauge, Robert H.; Smalley, Richard E.; Marek, Irene Morin; Rice University; United States Patent and Trademark Office
    The present invention is directed to fibers of epitaxially grown single-wall carbon nanotubes (SWNTs) and methods of making same. Such methods generally comprise the steps of: (a) providing a spun SWNT fiber; (b) cutting the fiber substantially perpendicular to the fiber axis to yield a cut fiber; (c) etching the cut fiber at its end with a plasma to yield an etched cut fiber; (d) depositing metal catalyst on the etched cut fiber end to form a continuous SWNT fiber precursor; and (e) introducing feedstock gases under SWNT growth conditions to grow the continuous SWNT fiber precursor into a continuous SWNT fiber.
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    Length-based liquid-liquid extraction of carbon nanotubes using a phase transfer catalyst
    (2009-08-25) Ziegler, Kirk J.; Schmidt, Daniel J.; Hauge, Robert H.; Smalley, Richard E.; Marek, Irene Morin; Rice University; United States Patent and Trademark Office
    The present invention is generally directed to new liquid-liquid extraction methods for the length-based separation of carbon nanotubes (CNTs) and other 1-dimensional nanostructures. In some embodiments, such methods are directed to separating SWNTs on the basis of their length, wherein such methods comprise the steps of: (a) functionalizing SWNTs to form functionalized SWNTs with ionizable functional moieties; (b) dissolving said functionalized SWNTs in a polar solvent to form a polar phase; (c) dissolving a substoichiometric (relative to the amount of ionizable functional moieties present on the SWNTs) amount of a phase transfer agent in a non-polar solvent to form a non-polar phase; (d) combining the polar and non-polar phases to form a bi-phase mixture; (e) adding a cationic donor species to the bi-phase mixture; and (f) agitating the bi-phase mixture to effect the preferential transport of short SWNTs into the non-polar phase such that the non-polar phase is enriched in short SWNTs and the polar phase is enriched in longer SWNTs. In other embodiments, analogous methods are used for the length-based separation of any type of CNT, and more generally, for any type of 1-dimensional nanostructure.
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    Methods for selective functionalization and separation of carbon nanotubes
    (2011-02-15) Strano, Michael S.; Usrey, Monica; Barone, Paul; Dyke, Christopher A.; Tour, James M.; Kittrell, Carter W.; Hauge, Robert H.; Smalley, Richard E.; Marek, Irene Morin; Rice University; United States Patent and Trademark Office
    The present invention is directed toward methods of selectively functionalizing carbon nanotubes of a specific type or range of types, based on their electronic properties, using diazonium chemistry. The present invention is also directed toward methods of separating carbon nanotubes into populations of specific types or range(s) of types via selective functionalization and electrophoresis, and also to the novel compositions generated by such separations.
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    Multi-step purification of single-wall carbon nanotubes
    (2010-03-02) Hauge, Robert H.; Xu, Ya-Qiong; Peng, Haiqing; Smalley, Richard E.; Marek, Irene Morin; Rice University; United States Patent and Trademark Office
    The present invention relates to processes for the purification of single-wall carbon nanotubes (SWNTs). Known methods of single-wall carbon nanotube production result in a single-wall carbon nanotube product that contains single-wall carbon nanotubes in addition to impurities including residual metal catalyst particles and amounts of small amorphous carbon sheets that surround the catalyst particles and appear on the side of the single-wall carbon nanotubes. The present purification processes remove the extraneous carbon as well as metal-containing residual catalyst particles.
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    Ozonation of carbon nanotubes in fluorocarbons
    (2008-12-30) Ziegler, Kirk J.; Shaver, Jonah; Hauge, Robert H.; Marek, Irene Morin; Rice University; United States Patent and Trademark Office
    The present invention is generally directed to methods of ozonating CNTs in fluorinated solvents (fluoro-solvents), wherein such methods provide a less dangerous alternative to existing ozonolysis methods. In some embodiments, such methods comprise the steps of: (a) dispersing carbon nanotubes in a fluoro-solvent to form a dispersion; and (b) reacting ozone with the carbon nanotubes in the dispersion to functionalize the sidewalls of the carbon nanotubes and yield functionalized carbon nanotubes with oxygen-containing functional moieties. In some such embodiments, the fluoro-solvent is a fluorocarbon solvent, such as a perfluorinated polyether.
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    Purification of carbon nanotubes based on the chemistry of fenton's reagent
    (2009-02-24) Marek, Irene Morin; Wang, Yuhuang; Hauge, Robert H.; Shan, Hongwei; Rice University; United States Patent and Trademark Office
    The present invention is directed to methods of purifying carbon nanotubes (CNTs). In general, such methods comprise the following steps: (a) preparing an aqueous slurry of impure CNT material; (b) establishing a source of Fe2+ ions in the slurry to provide a catalytic slurry; (c) adding hydrogen peroxide to the catalytic slurry to provide an oxidative slurry, wherein the Fe2+ ions catalyze the production of hydroxyl radicals; and (d) utilizing the hydroxyl radicals in the oxidative slurry to purify the CNT material and provide purified CNTs.