Browsing by Author "Schmidt, Howard K."

Now showing 1 - 11 of 11
  • Thumbnail Image
    Item
    Amplification of carbon nanotubes via seeded-growth methods
    (2013-10-22) Smalley, Richard E.; Hauge, Robert H.; Barron, Andrew R.; Tour, James M.; Schmidt, Howard K.; Billups, Edward W.; Dyke, Christopher A.; Moore, Valerie C.; Whitsitt, Elizabeth Anne; Anderson, Robin E.; Colorado Jr., Ramon; Stewart, Michael P.; Ogrin, Douglas C.; Rice University; United States Patent and Trademark Office
    The present invention is directed towards methods (processes) of providing large quantities of carbon nanotubes (CNTs) of defined diameter and chirality (i.e., precise populations). In such processes, CNT seeds of a pre-selected diameter and chirality are grown to many (e.g., hundreds) times their original length. This is optionally followed by cycling some of the newly grown material back as seed material for regrowth. Thus, the present invention provides for the large-scale production of precise populations of CNTs, the precise composition of such populations capable of being optimized for a particular application (e.g., hydrogen storage). The present invention is also directed to complexes of CNTs and transition metal catalyst precurors, such complexes typically being formed en route to forming CNT seeds.
  • Thumbnail Image
    Item
    Bulk cutting of carbon nanotubes using electron beam irradiation
    (2013-09-24) Ziegler, Kirk J.; Rauwald, Urs; Hauge, Robert H.; Schmidt, Howard K.; Smalley, Richard E.; Kittrell, Carter W.; Gu, Zhenning; Rice University; United States Patent and Trademark Office
    According to some embodiments, the present invention provides a method for attaining short carbon nanotubes utilizing electron beam irradiation, for example, of a carbon nanotube sample. The sample may be pretreated, for example by oxonation. The pretreatment may introduce defects to the sidewalls of the nanotubes. The method is shown to produces nanotubes with a distribution of lengths, with the majority of lengths shorter than 100 tun. Further, the median length of the nanotubes is between about 20 nm and about 100 nm.
  • Thumbnail Image
    Item
    Carbon nanotube diameter selection by pretreatment of metal catalysts on surfaces
    (2012-02-28) Hauge, Robert H.; Xu, Ya-Qiong; Shan, Hongwei; Nicholas, Nolan Walker; Kim, Myung Jong; Schmidt, Howard K.; Kittrell, Carter W.; Rice University; United States Patent and Trademark Office
    A new and useful nanotube growth substrate conditioning processes is herein disclosed that allows the growth of vertical arrays of carbon nanotubes where the average diameter of the nanotubes can be selected and/or controlled as compared to the prior art.
  • Thumbnail Image
    Item
    Carbon nanotube substrates and catalyzed hot stamp for polishing and patterning the substrates
    (2009-09-08) Wang, Yuhuang; Hauge, Robert H.; Schmidt, Howard K.; Kim, Myung Jong; Kittrell, Carter W.; Rice University; United States Patent and Trademark Office
    The present invention is generally directed to catalyzed hot stamp methods for polishing and/or patterning carbon nanotube-containing substrates. In some embodiments, the substrate, as a carbon nanotube fiber end, is brought into contact with a hot stamp (typically at 200-800° C.), and is kept in contact with the hot stamp until the morphology/patterns on the hot stamp have been transferred to the substrate. In some embodiments, the hot stamp is made of material comprising one or more transition metals (Fe, Ni, Co, Pt, Ag, Au, etc.), which can catalyze the etching reaction of carbon with H2, CO2, H2O, and/or O2. Such methods can (1) polish the carbon nanotube-containing substrate with a microscopically smooth finish, and/or (2) transfer pre-defined patterns from the hot stamp to the substrate. Such polished or patterned carbon nanotube substrates can find application as carbon nanotube electrodes, field emitters, and field emitter arrays for displays and electron sources.
  • Thumbnail Image
    Item
    Electrical device fabrication from nanotube formations
    (2013-03-12) Nicholas, Nolan Walker; Kittrell, Carter W.; Kim, Myung Jong; Schmidt, Howard K.; Rice University; United States Patent and Trademark Office
    A method for forming nanotube electrical devices, arrays of nanotube electrical devices, and device structures and arrays of device structures formed by the methods. Various methods of the present invention allow creation of semiconducting and/or conducting devices from readily grown SWNT carpets rather than requiring the preparation of a patterned growth channel and takes advantage of the self-controlling nature of these carpet heights to ensure a known and controlled channel length for reliable electronic properties as compared to the prior methods.
  • Thumbnail Image
    Item
    Embedded arrays of vertically aligned carbon nanotube carpets and methods for making them
    (2015-06-30) Kim, Myung Jong; Nicholas, Nolan Walker; Kittrell, Carter W.; Schmidt, Howard K.; Rice University; United States Patent and Trademark Office
    According to some embodiments, the present invention provides a system and method for supporting a carbon nanotube array that involve an entangled carbon nanotube mat integral with the array, where the mat is embedded in an embedding material. The embedding material may be depositable on a carbon nanotube. A depositable material may be metallic or nonmetallic. The embedding material may be an adhesive material. The adhesive material may optionally be mixed with a metal powder. The embedding material may be supported by a substrate or self-supportive. The embedding material may be conductive or nonconductive. The system and method provide superior mechanical and, when applicable, electrical, contact between the carbon nanotubes in the array and the embedding material. The optional use of a conductive material for the embedding material provides a mechanism useful for integration of carbon nanotube arrays into electronic devices.
  • Thumbnail Image
    Item
    Flow dielectrophoretic separation of single wall carbon nanotubes
    (2012-01-17) Schmidt, Howard K.; Peng, Haiqing; Mendes, Manuel Joao; Pasquali, Matteo; Rice University; United States Patent and Trademark Office
    According to some embodiments, a method for separating a first fraction of a single wall carbon nanotubes and a second fraction of single wall carbon nanotubes includes, but is not limited to: flowing a solution comprising the nanotubes into a dielectrophoresis chamber; applying a DC voltage, in combination with an AC voltage, to the dielectrophoresis chamber; and collecting a first eluent from the dielectrophoresis chamber, wherein the first eluent comprises the first fraction and is depleted of the second fraction, wherein the first and second fractions differ by at least one of conductivity, diameter, length, and combinations thereof.
  • Thumbnail Image
    Item
    Graphene compositions and drilling fluids derived therefrom
    (2012-05-22) Tour, James M.; Schmidt, Howard K.; Lomeda, Jay R.; Kosynkin, Dmitry V.; Doyle, Condell D.; Rice University; United States Patent and Trademark Office
    Drilling fluids comprising graphenes and nanoplatelet additives and methods for production thereof are disclosed. Graphene includes graphite oxide, graphene oxide, chemically-converted graphene, and functionalized chemically-converted graphene. Derivatized graphenes and methods for production thereof are disclosed. The derivatized graphenes are prepared from a chemically-converted graphene through derivatization with a plurality of functional groups. Derivatization can be accomplished, for example, by reaction of a chemically-converted graphene with a diazonium species. Methods for preparation of graphite oxide are also disclosed.
  • Thumbnail Image
    Item
    Graphene compositions and methods for production thereof
    (2013-01-29) Tour, James M.; Schmidt, Howard K.; Doyle, Condell D.; Kosynkin, Dmitry V.; Lomeda, Jay R.; Rice University; United States Patent and Trademark Office
    Drilling fluids comprising graphenes and nanoplatelet additives and methods for production thereof are disclosed. Graphene includes graphite oxide, graphene oxide, chemically-converted graphene, and functionalized chemically-converted graphene. Derivatized graphenes and methods for production thereof are disclosed. The derivatized graphenes are prepared from a chemically-converted graphene through derivatization with a plurality of functional groups. Derivatization can be accomplished, for example, by reaction of a chemically-converted graphene with a diazonium species. Methods for preparation of graphite oxide are also disclosed.
  • Thumbnail Image
    Item
    Methods for magnetic imaging of geological structures
    (2012-09-18) Schmidt, Howard K.; Tour, James M.; Rice University; United States Patent and Trademark Office
    Methods for imaging geological structures include injecting magnetic materials into the geological structures, placing at least one magnetic probe in a proximity to the geological structures, generating a magnetic field in the geological structures and detecting a magnetic signal. The at least one magnetic probe may be on the surface of the geological structures or reside within the geological structures. The methods also include injecting magnetic materials into the geological structures, placing at least one magnetic detector in the geological structures and measuring a resonant frequency in the at least one magnetic detector. Methods for using magnetic materials in dipole-dipole, dipole-loop and loop-loop transmitter-receiver configurations for geological structure electromagnetic imaging techniques are also disclosed.
  • Thumbnail Image
    Item
    Nanoparticle/nanotube-based nanoelectronic devices and chemically-directed assembly thereof
    (2011-02-22) Schmidt, Howard K.; Rice University; United States Patent and Trademark Office
    According to some embodiments, the present invention provides a nanoelectronic device based on a nanostructure that may include a nanotube with first and second ends, a metallic nanoparticle attached to the first end, and an insulating nanoparticle attached to the second end. The nanoelectronic device may include additional nanostructures so a to form a plurality of nanostructures comprising the first nanostructure and the additional nanostructures. The plurality of nanostructures may arranged in a network comprising a plurality of edges and a plurality of vertices, wherein each edge comprises a nanotube and each vertex comprises at least one insulating nanoparticle and at least one metallic nanoparticle adjacent the insulating nanoparticle. The combination of at least one edge and at least one vertex comprises a diode. The device may be an optical rectenna.