Browsing by Author "Smalley, Richard E."
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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 OfficeThe 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.Item Applications and production of carbon nanotubes(1998) Hafner, Jason Howard; Smalley, Richard E.Carbon nanotubes, a recently discovered form of carbon fiber with structural perfection similar to that of a fullerene molecule, have interesting electronic, chemical and mechanical properties due to their size and structure. Nanotubes have great potential as a bulk material for strong, lightweight composite materials, and as individual nano-scale tools or devices. Initial work on applications with individual multiwalled nanotubes as field emission sources and scanning force microscopy tips is described. The nanotubes display intriguing field emission behavior interpreted as the nanotube unraveling under the influence of the electric field. The unraveling process is believed to result in facile field emission from linear atomic carbon chains at the end of the nanotube. Such atomic wires represent an excellent field emitter. The work on multiwalled nanotube SFM tips was equally encouraging. The high aspect ratio of the nanotube allows it to image deep trenches inaccessible to commercially available Si pyramidal tips, and it reduces the interaction with the ambient water layer on the sample which perturbs image quality. The most remarkable advantage of nanotube SFM tips is a result of their mechanical properties. It was found that the nanotubes will remain rigid during normal imaging, but conveniently buckle to the side if circumstances arise which create large forces known to damage the tip and sample. This feature makes the tip more durable than Si tips, and is especially important for soft biological samples. In these two applications, as well as others, and in the measurements of novel nanotube properties, high quality, small diameter (0.5 to 2 nm) diameter single-walled nanotubes are most interesting. Such material can be produced slowly and in small amounts by catalytic arc vaporization and catalytic laser vaporization of graphite. It is well known that nanotubes can be mass produced by catalytic chemical vapor deposition (CCVD), but the product consists only of large, defective multiwalled nanotubes. It has been found that the standard CCVD technique can be made to exclusively produce small single-walled nanotubes by lowering the concentration of reactants. It is shown that this change in product morphology is a result of a change in the rate limiting step of the CCVD reaction. Nanotube nucleation and growth termination are also studied for this CCVD system. Prospects for mass production of single-walled nanotubes by this modified CCVD technique are considered.Item Array of fullerene nanotubes(2009-12-15) Smalley, Richard E.; Colbert, Daniel T.; Dai, Hongjie; Liu, Jie; Rinzler, Andrew G.; Hafner, Jason H.; Smith, Kenneth A.; Guo, Ting; Nikolaev, Pavel; Thess, Andreas; Rice University; United States Patent and Trademark OfficeThis invention relates generally to forming an array of fullerene nanotubes. In one embodiment, a macroscopic molecular array is provided comprising at least about 106 fullerene nanotubes in generally parallel orientation and having substantially similar lengths in the range of from about 5 to about 500 nanometers.Item Array of single-wall carbon nanotubes(2006-07-04) Smalley, Richard E.; Colbert, Daniel T.; Dai, Hongjie; Liu, Jie; Rinzler, Andrew G.; Hafner, Jason H.; Smith, Kenneth A.; Guo, Ting; Nikolaev, Pavel; Thess, Andreas; Rice University; United States Patent and Trademark OfficeThis invention relates generally to forming an array of single-wall carbon nanotubes (SWNT). In one embodiment, a macroscopic molecular array is provided comprising at least about 106 single-wall carbon nanotubes in generally parallel orientation and having substantially similar lengths in the range of from about 5 to about 500 nanometers.Item Band evolution and shell structure in large clusters: Aluminum(3-60)anion, copper(1-1113)anion, silver(1-58)anion, and gold(1-223)anion(1990) Taylor, Kelly J.; Smalley, Richard E.Photoelectron spectroscopy of negatively, charged clusters of aluminum, copper, silver, and gold reveals electronic shell structure and electron energy band development. Photodetachment experiments on Au$\sb6\sp-$ also suggests that an image-bound state of the anion exists at the detachment threshold. Al$\sb{\rm x}$, Cu$\sb{\rm x}$, Ag$\sb{\rm x}$, and Au$\sb{\rm x}$ all show closed shells in their electron affinities for clusters with x $<$ 21. The electron affinities of Au$\sb{\rm x}$ for 20 $<$ x $<$ 60 have three spherical shells at x = 20, 34, and 58, all of which are dramatically manifested in dips of 1.2, 0.65, and 0.75 eV when compared to their adjacent lower mass neighbors. The photoelectron spectra of Ag$\sb{\rm x}\sp-$, 30 $<$ x $<$ 58, have cleanly resolved peaks that are a result of level structure in the density-of-states and they are predicted by the Nilsson-Clemenger formalism of shell theory. Copper clusters in the same size range show similar behavior although not as pronounced. The onset of the 3d-band in copper is monotonically increasing with cluster size and at Cu$\sb{410}$ the band is only 0.6 eV from its bulk value. The monotonic increase is a result of the expanding sphere of charge that induces a dipole as the electron leaves the vicinity of the cluster. Sharp features in the 3d-band onset are very similar to bulk photoemission spectra and suggest that these structures are beginning to show crystalline character. The induced dipole also causes at least one weakly bound state to exist for Au$\sb6\sp-$ at the detachment threshold. Photodetachment spectroscopy shows a 30 cm$\sp{-1}$ phase shift between the 1- and 2-photon ejected electrons. The phase shift may be due to a sequence congestion of vibrational states between the ground and image-bound electronic states of Au$\sb6\sp-$.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 OfficeAccording 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.Item Carbon fibers formed from single-wall carbon nanotubes(2004-01-27) Smalley, Richard E.; Colbert, Daniel T.; Dai, Hongjie; Liu, Jie; Rinzler, Andrew G.; Hafner, Jason H.; Smith, Kenneth A.; Guo, Ting; Nikolaev, Pavel; Thess, Andreas; Rice University; United States Patent and Trademark OfficeA method for purifying a mixture comprising single-wall carbon nanotubes and amorphous carbon contaminate is disclosed. The method includes the steps of heating the mixture under oxidizing conditions sufficient to remove the amorphous carbon, followed by recovering a product comprising at least about 80% by weight of single-wall carbon nanotubes. A method for producing tubular carbon molecules of about 5 to 500 nm in length is also disclosed. The method includes the steps of cutting single-wall nanotube containing-material to form a mixture of tubular carbon molecules having lengths in the range of 5-500 nm and isolating a fraction of the molecules having substantially equal lengths. The nanotubes may be used, singularly or in multiples, in power transmission cables, in solar cells, in batteries, as antennas, as molecular electronics, as probes and manipulators, and in composites.Item Catalytic growth of single- and double-wall carbon nanotubes from metal particles(2006-10-24) Smalley, Richard E.; Hafner, Jason H.; Colbert, Daniel T.; Smith, Kenneth A.; Rice University; United States Patent and Trademark OfficeSingle-walled carbon nanotubes have been synthesized by the catalytic decomposition of both carbon monoxide and ethylene over a supported metal catalyst known to produce larger multi-walled nanotubes. Under certain conditions, there is no termination of nanotube growth, and production appears to be limited only by the diffusion of reactant gas through the product nanotube mat that covers the catalyst. The present invention concerns a catalyst-substrate system which promotes the growth of nanotubes that are predominantly single-walled tubes in a specific size range, rather than the large irregular-sized multi-walled carbon fibrils that are known to grow from supported catalysts. With development of the supported catalyst system to provide an effective means for production of single-wall nanotubes, and further development of the catalyst geometry to overcome the diffusion limitation, the present invention will allow bulk catalytic production of predominantly single-wall carbon nanotubes from metal catalysts located on a catalyst supporting surface.Item Catalytic growth of single-and double-wall carbon nanotubes from metal particles(2007-04-10) Smalley, Richard E.; Hafner, Jason H.; Colbert, Daniel T.; Smith, Kenneth A.; Rice University; United States Patent and Trademark OfficeThe present invention concerns a method for growing carbon nanotubes using a catalyst system that preferentially promotes the growth of single- and double-wall carbon nanotubes, rather than larger multi-walled carbon nanotubes. Ropes of the carbon nanotubes are formed that comprise single-wall and/or double-wall carbon nanotubes.Item Catalytic growth of single-wall carbon nanotubes from metal particles(2004-02-17) Smalley, Richard E.; Hafner, Jason H.; Colbert, Daniel T.; Smith, Kenneth A.; Rice University; United States Patent and Trademark OfficeSingle-walled carbon nanotubes have been synthesized by the catalytic decomposition of both carbon monoxide and ethylene over a supported metal catalyst known to produce larger multi-walled nanotubes. Under certain conditions, there is no termination of nanotube growth, and production appears to be limited only by the diffusion of reactant gas through the product nanotube mat that covers the catalyst The present invention concerns a catalyst-substrate system which promotes the growth of nanotubes that are predominantly single-walled tubes in a specific size range, rather than the large irregular-sized multi-walled carbon fibrils that are known to grow from supported catalysts. With development of the supported catalyst system to provide an effective means for production of single-wall nanotubes, and further development of the catalyst geometry to overcome the diffusion limitation, the present invention will allow bulk catalytic production of predominantly single-wall carbon nanotubes from metal catalysts located on a catalyst supporting surface.Item Catalytic growth of single-walled nanotubes by laser vaporization(1996) Nikolaev, Pavel; Smalley, Richard E.Direct laser vaporization of transition-metal/graphite composite rods produced single-walled carbon nanotubes (SWT) in the condensing vapor in a heated flow tube. A much higher yield of nanotubes was found, with little of the amorphous overcoating on those produced by the metal-catalyzed arc-discharge method. A number of parameters were varied to achieve the highest yield. A mixture of Co with Ni catalyzed about 50% of all the carbon vaporized to SWT. A model for SWT growth is presented for both the present case and the arc.Item Chemical derivatization of single-wall carbon nanotubes to facilitate solvation thereof- and use of derivatized nanotubes(2004-12-28) Margrave, John L.; Mickelson, Edward T.; Hauge, Robert H.; Boul, Peter; Huffman, Chad; Liu, Jie; Smalley, Richard E.; Smith, Kenneth A.; Colbert, Daniel T.; Rice University; United States Patent and Trademark OfficeThis invention is directed to making chemical derivatives of carbon nanotubes and to uses for the derivatized nanotubes, including making arrays as a basis for synthesis of carbon fibers. In one embodiment, this invention also provides a method for preparing single wall carbon nanotubes having substituents attached to the side wall of the nanotube by reacting single wall carbon nanotubes with fluorine gas and recovering fluorine derivatized carbon nanotubes, then reacting fluorine derivatized carbon nanotubes with a nucleophile. Some of the fluorine substituents are replaced by nucleophilic substitution. If desired, the remaining fluorine can be completely or partially eliminated to produce single wall carbon nanotubes having substituents attached to the side wall of the nanotube. The substituents will, of course, be dependent on the nucleophile, and preferred nucleophiles include alkyl lithium species such as methyl lithium. Alternatively, fluorine may be fully or partially removed from fluorine derivatized carbon nanotubes by reacting the fluorine derivatized carbon nanotubes with various amounts of hydrazine, substituted hydrazine or alkyl amine. The present invention also provides seed materials for growth of single wall carbon nanotubes comprising a plurality of single wall carbon nanotubes or short tubular molecules having a catalyst precursor moiety covalently bound or physisorbed on the outer surface of the sidewall to provide the optimum metal cluster size under conditions that result in migration of the metal moiety to the tube end.Item Chemical derivatization of single-wall carbon nanotubes to facilitate solvation thereof; and use of derivatized nanotubes to form catalyst-containing seed materials for use in making carbon fibers(2003-11-11) Margrave, John L.; Mickelson, Edward T.; Hauge, Robert H.; Boul, Peter; Huffman, Chad; Liu, Jie; Smalley, Richard E.; Smith, Kenneth A.; Colbert, Daniel T.; Rice University; United States Patent and Trademark OfficeThis invention is directed to making chemical derivatives of carbon nanotubes and to uses for the derivatized nanotubes, including making arrays as a basis for synthesis of carbon fibers. In one embodiment, this invention also provides a method for preparing single wall carbon nanotubes having substituents attached to the side wall of the nanotube by reacting single wall carbon nanotubes with fluorine gas and recovering fluorine derivatized carbon nanotubes, then reacting fluorine derivatized carbon nanotubes with a nucleophile. Some of the fluorine substituents are replaced by nucleophilic substitution. If desired, the remaining fluorine can be completely or partially eliminated to produce single wall carbon nanotubes having substituents attached to the side wall of the nanotube. The substituents will, of course, be dependent on the nucleophile, and preferred nucleophiles include alkyl lithium species such as methyl lithium. Alternatively, fluorine may be fully or partially removed from fluorine derivatized carbon nanotubes by reacting the fluorine derivatized carbon nanotubes with various amounts of hydrazine, substituted hydrazine or alkyl amine. The present invention also provides seed materials for growth of single wall carbon nanotubes comprising a plurality of single wall carbon nanotubes or short tubular molecules having a catalyst precursor moiety covalently bound or physisorbed on the outer surface of the sidewall to provide the optimum metal cluster size under conditions that result in migration of the metal moiety to the tube end.Item Chemically modifying single wall carbon nanotubes to facilitate dispersal in solvents(2005-04-05) Margrave, John L.; Mickelson, Edward T.; Hauge, Robert H.; Boul, Peter; Huffman, Chad; Liu, Jie; Smalley, Richard E.; Smith, Kenneth A.; Colbert, Daniel T.; Rice University; United States Patent and Trademark OfficeThis invention is directed to making chemical derivatives of carbon nanotubes and to uses for the derivatized nanotubes, including making arrays as a basis for synthesis of carbon fibers. In one embodiment, this invention also provides a method for preparing single wall carbon nanotubes having substituents attached to the side wall of the nanotube by reacting single wall carbon nanotubes with fluorine gas and recovering fluorine derivatized carbon nanotubes, then reacting fluorine derivatized carbon nanotubes with a nucleophile. Some of the fluorine substituents are replaced by nucleophilic substitution. If desired, the remaining fluorine can be completely or partially eliminated to produce single wall carbon nanotubes having substituents attached to the side wall of the nanotube. The substituents will, of course, be dependent on the nucleophile, and preferred nucleophiles include alkyl lithium species such as methyl lithium. Alternatively, fluorine may be fully or partially removed from fluorine derivatized carbon nanotubes by reacting the fluorine derivatized carbon nanotubes with various amounts of hydrazine, substituted hydrazine or alkyl amine. The present invention also provides seed materials for growth of single wall carbon nanotubes comprising a plurality of single wall carbon nanotubes or short tubular molecules having a catalyst precursor moiety covalently bound or physisorbed on the outer surface of the sidewall to provide the optimum metal cluster size under conditions that result in migration of the metal moiety to the tube end.Item Chemisorption of hydrogen(2) and carbon monoxide on positive transition metal cluster ions in an FT-ICR apparatus(1989) Weiss, Falk Dietrich; Smalley, Richard E.A new FT-ICR apparatus (Fourier Transform - Ion Cyclotron Resonance) has been developed, where clusters produced in a laser vaporization supersonic cluster source were efficiently injected and trapped in an elongated cylindrical Penning type ion trap located in the center of a magnetic field of 6 Tesla. The successful injection of multiple cluster pulses into the ion trap makes the experiment largely independent of the intensity of the supersonic cluster source. Long trapping times of up to 30 minutes and a high mass resolution are additional features of this apparatus. In a first application, the apparatus was used to systematically investigate the chemisorption behavior of positively-charged group V and group IX transition metal cluster ions towards H$\sb2$. The absolute rate constant of the chemisorption process for the addition of the first hydrogen molecule as well as the saturation values for the complete hydrogenation of the clusters were measured. In the cases of Vanadium, Niobium and Cobalt, the reactivity of the positive cluster ions were then compared to the reactivity of the neutral cluster species. The patterns in reactivity for the positive as well as for the neutral clusters showed striking similarities. This led to the conclusion that the reactivity of these clusters is by and large independent of their charge state. Within the niobium and tantalum cluster series isomeric forms of a particular cluster species were found exhibiting a large difference in reactivity towards hydrogen. In the third series of cluster experiments performed on the FT-ICR apparatus, the chemisorption of CO on positively-charged group IX transition metal cluster ions was investigated. In the case of rhodium, the measured saturation values for these gas phase cluster carbonyls scaled parallel to the saturation values found for the rhodium carbonyl clusters in the liquid phase indicating similar structures for both gas phase as well as liquid phase clusters. In the presence of oxygen which is dissociatively chemisorbed on the clusters' surface, formation and desorption of CO$\sb2$ were found during the CO chemisorption process on all three group IX metals.Item Clusters as models of bulk surfaces and novel materials(1992) Jin, Changming; Smalley, Richard E.Studies on gas phase clusters show that common ground exists between clusters and bulk surfaces such that clusters can serve as models of bulk surfaces. Several cluster systems are studied to probe this cluster-surface analogy with both ultraviolet photoelectron spectroscopy (UPS) and Fourier transform ion cyclotron resonance (FT-ICR). Ultraviolet photoelectron spectra of GaAs cluster anions are measured with a photon energy of 7.9 eV. The electron affinity displays a strong even/odd oscillation suggesting the presence of a substantial gap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) in the corresponding neutral clusters. The absence of unpaired electrons in even numbered neutral clusters is reminiscent of the healed dangling bonds caused by the reconstruction and relaxation at GaAs bulk surfaces. Chemical reactions of noble and transition metal clusters with CO and H$\sb2$ are studied with FT-ICR. The chemistry and physics of these metal cluster plus adsorbates systems are also modeled well by using the cluster shell model originally developed for metal bulk solids and surfaces. Excellent interplay between theory and experiment on the Cu$\sb{\rm x}\sp+$CO systems reveals the major advantage for the cluster model of bulk surfaces. New materials are prepared in the course of studying gas phase carbon clusters. Laser vaporization of a graphite/BN composite disk produces fullerenes in which one or more atoms of the hollow carbon cage is replaced by a boron atom. These boron-doped fullerenes are found to act as Lewis acid when they chemisorb ammonia molecules. Fullerenes with one or more metal atoms inside are also generated both in gas phase and in macroscopic quantities. The formation mechanism of the multi-metal doped fullerenes is proposed as due to coalescence. These new materials are expected to have interesting, novel, and useful properties.Item Continued growth of single-walled carbon nanotubes from open-ended SWNT substrates(2006) Kim, Myung Jong; Hafner, Jason H.; Smalley, Richard E.We prepared nanoscopically flat open-ended SWNT substrates from SWNT spun fibers by using the microtome cutting technique or the focused ion beam cutting technique followed by various etching and cleaning schemes or alternatively from vertically aligned SWNT film by flipping-over. Deposited catalyst was docked to the open ends of SWNTs, and carbon feedstocks were catalyzed into continued single-walled carbon nanotube growth resembling 1D molecular epitaxy. The data obtained from Raman spectroscopy indicates that the (n, m) structure of the newly grown SWNT was cloned from that of the pre-existing SWNT substrate. Such results lead us to believe that this method will provide us with a means of chirality-controlled SWNTs growth on a macroscopic scale using a fairy general and scalable setup in the future.Item Continuous fiber of fullerene nanotubes(2010-02-02) Smalley, Richard E.; Colbert, Daniel T.; Dai, Hongjie; Liu, Jie; Rinzler, Andrew G.; Hafner, Jason H.; Smith, Kenneth A.; Guo, Ting; Nikolaev, Pavel; Thess, Andreas; Rice University; United States Patent and Trademark OfficeThis invention relates generally to carbon fiber produced from fullerene nanotube arrays. In one embodiment, the present invention involves a macroscopic carbon fiber comprising at least 106 fullerene nanotubes in generally parallel orientation.Item Continuous fiber of single-wall carbon nanotubes(2006-08-29) Colbert, Daniel T.; Dai, Hongjie; Hafner, Jason H.; Rinzler, Andrew G.; Smalley, Richard E.; Rice University; United States Patent and Trademark OfficeThis invention relates generally to carbon fiber produced from single-wall carbon nanotube (SWNT) molecular arrays. In one embodiment, the carbon fiber which comprises an aggregation of substantially parallel carbon nanotubes comprises more than one molecular array. Another embodiment of this invention is a large cable-like structure with enhanced tensile properties comprising a number of smaller separate arrays. In another embodiment, a composite structure is disclosed in which a central core array of metallic SWNTs is surrounded by a series of smaller circular non-metallic SWNT arrays.Item Continuous fiber of single-wall carbon nanotubes(2005-12-27) Smalley, Richard E.; Colbert, Daniel T.; Dai, Hongjie; Liu, Jie; Rinzler, Andrew G.; Hafner, Jason H.; Smith, Kenneth A.; Guo, Ting; Nikolaev, Pavel; Thess, Andreas; Rice University; United States Patent and Trademark OfficeThis invention relates generally to carbon fiber produced from single-wall carbon nanotube (SWNT) molecular arrays. In one embodiment, the present invention involves a macroscopic carbon fiber comprising at least 106 signal-wall carbon nanotubes in generally parallel orientation.