Abstract: A method for cutting single-wall carbon nanotubes involves partially fluorinating single-wall carbon nanotubes and pyrolyzing the partially fluorinated nanotubes in an inert atmosphere or vacuum up to about 1000° C. The nanotubes are optionally purified before cutting. The partial fluorination involves fluorinating the nanotubes to a carbon-fluorine stoichiometry of CFx, where x is up to about 0.3. The invention also relates to the derivatization of fluorinated and cut single-wall carbon nanotubes. The single-wall carbon nanotubes can be cut to any length depending on the fluorination and pyrolysis conditions. Short nanotubes are useful in various applications, such as field emitters for flat panel displays and as “seeds” for further nanotube growth.

Abstract: The present invention is directed to at least one method and at least one apparatus for determining the length of single-wall carbon nanotubes (SWNTs). The method generally comprises the steps of: dispersing a sample of SWNTs into a suitable dispersing medium to form a solvent-suspension of solvent-suspended SWNTs; determining the mean SWNT diameter of the solvent-suspended SWNTs; introducing the solvent-suspended SWNTs into a viscosity-measuring device; obtaining a specific viscosity for the SWNT solvent-suspension; and determining the length of the SWNTs based upon the specific viscosity by solving, for example, the Kirkwood-Auer equation corrected by Batchelor's formula for the drag on a slender cylinder for “L,” to determine the length of the SWNTs.

Abstract: A gas-phase method for producing high yields of single-wall carbon nanotubes with high purity and homogeneity is disclosed. The method involves using preformed metal catalyst clusters to initiate and grow single-wall carbon nanotubes. In one embodiment, multi-metallic catalyst precursors are used to facilitate the metal catalyst cluster formation. The catalyst clusters are grown to the desired size before mixing with a carbon-containing feedstock at a temperature and pressure sufficient to initiate and form single-wall carbon nanotubes. The method also involves using small fullerenes and preformed sections of single-wall carbon nanotubes, either derivatized or underivatized, as seed molecules for expediting the growth and increasing the yield of single-wall carbon nanotubes. The multi-metallic catalyst precursors and the seed molecules may be introduced into the reactor by means of a supercritical fluid. In addition the seed molecules may be introduced into the reactor via an aerosol or smoke.

Abstract: This invention is directed to the fluorination (or derivatization with alternative chemical species) of fullerene carbon nanocages as an efficient way to (a) facilitate synthesis of endohedral complexes by a significant reduction or elimination of the barriers for the entry of guest-ions, -atoms or molecules, and (b) to preserve the chemical stability of final product.

Abstract: The present invention relates to a process for the purification of single-wall carbon nanotubes and the purified single-wall carbon nanotube material. 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 sides of the single-wall carbon nanotubes and “ropes” of single-wall carbon nanotubes. The purification process removes the extraneous carbon as well as metal-containing residual catalyst particles. The process employs steps including a gas-phase oxidation of the amorphous carbon and subsequent liquid-phase reaction of a halogen-containing acid with the metal-containing species. Optionally, the single-wall carbon nanotube material may be annealed dry or in the presence of moisture.

Abstract: The invention relates to a process for sorting and separating a mixture of (n, m) type single-wall carbon nanotubes according to (n, m) type. A mixture of (n, m) type single-wall carbon nanotubes is suspended such that the single-wall carbon nanotubes are individually dispersed. The nanotube suspension can be done in a surfactant-water solution and the surfactant surrounding the nanotubes keeps the nanotube isolated and from aggregating with other nanotubes. The nanotube suspension is acidified to protonate a fraction of the nanotubes. An electric field is applied and the protonated nanotubes migrate in the electric fields at different rates dependent on their (n, m) type. Fractions of nanotubes are collected at different fractionation times. The process of protonation, applying an electric field, and fractionation is repeated at increasingly higher pH to separated the (n, m) nanotube mixture into individual (n, m) nanotube fractions.

Abstract: The invention relates to macroscopic amounts of (n, m) type single-wall carbon nanotubes and sensing and monitoring devices comprising specific nanotube types. Selected (n, m)-type fractions of single-wall carbon nanotubes are separated from a suspension of mixed single-wall carbon nanotubes are individually dispersed and isolated. The nanotubes are isolated and precluded from reassociating with other nanotubes by encasing the nanotube with a non-perturbing molecular species, such as surfactant molecules or polymers that can wrap around the nanotube. In contrast to metallic single-wall carbon nanotubes, semiconducting single-wall carbon nanotubes have been found to fluoresce in the near-IR region of the electromagnetic spectrum. The nanotubes are very sensitive to environmental perturbations and the nanotube's fluorescence profile will be affected by these perturbations.

Abstract: A method for cutting single-wall carbon nanotubes involves partially fluorinating single-wall carbon nanotubes and pyrolyzing the partially fluorinated nanotubes in an inert atmosphere or vacuum up to about 1000° C. The nanotubes are optionally purified before cutting. The partial fluorination involves fluorinating the nanotubes to a carbon-fluorine stoichiometry of CFx, where x is up to about 0.3. The invention also relates to the derivatization of fluorinated and cut single-wall carbon nanotubes. The single-wall carbon nanotubes can be cut to any length depending on the fluorination and pyrolysis conditions. Short nanotubes are useful in various applications, such as field emitters for flat panel displays and as “seeds” for further nanotube growth.

Abstract: The present invention involves fibers of highly aligned single-wall carbon nanotubes and a process for making the same. The present invention provides a method for effectively dispersing single-wall carbon nanotubes. The process for dispersing the single-wall carbon nanotubes comprises mixing single-wall carbon nanotubes with 100% sulfuric acid or a superacid, heating and stirring under an inert, oxygen-free environment. The single-wall carbon nanotube/acid mixture is wet spun into a coagulant to form the single-wall carbon nanotube fibers. The fibers are recovered, washed and dried. The single-wall carbon nanotubes were highly aligned in the fibers, as determined by Raman spectroscopy analysis.

Abstract: A continuous gas-phase method for producing single-wall carbon nanotubes at high catalyst productivity and high yield is disclosed. The method involves the use of a novel in-situ formed catalyst to initiate and grow single-wall carbon nanotubes using a carbon-containing feedstock in a high temperature and pressure process. The catalyst comprises in-situ-generated transition metal particles in contact with in-situ-generated refractory particles. The population of nucleating sites for single-wall carbon nanotubes is enhanced due to the ease of formation of a population of refractory particles. These, in turn, improve the nucleation and stability of the transition metal particles that grow on them. The larger number of transition metal particles translate into a larger number of sites for single-wall carbon nanotube production. The higher catalyst yields provide a means for obtaining higher purity single-wall carbon nanotubes.

Abstract: The present invention involves alewives of highly aligned single-wall carbon nanotubes (SWNT), process for making the same and compositions thereof. The present invention provides a method for effectively making carbon alewives, which are discrete, acicular-shaped aggregates of aligned single-wall carbon nanotubes and resemble the Atlantic fish of the same name. Single-wall carbon nanotube alewives can be conveniently dispersed in materials such as polymers, ceramics, metals, metal oxides and liquids. The process for preparing the alewives comprises mixing single-wall carbon nanotubes with 100% sulfuric acid or a superacid, heating and stirring, and slowly introducing water into the single-wall carbon nanotube/acid mixture to form the alewives. The alewives can be recovered, washed and dried. The properties of the single-wall carbon nanotubes are retained in the alewives.

Abstract: The present invention relates to an all gas-phase process for the purification of single-wall carbon nanotubes and the purified single-wall carbon nanotube material. 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 sides of the single-wall carbon nanotubes and “ropes” of single-wall carbon nanotubes. The purification process removes the extraneous carbon as well as metal-containing residual catalyst particles. The process comprises oxidation of the single-wall carbon nanotube material, reduction and reaction of a halogen-containing gas with the metal-containing species. The oxidation step may be done dry or in the presence of water vapor.

Abstract: The present invention relates to a process for the purification of single-wall carbon nanotubes and the purified single-wall carbon nanotube material. 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 sides of the single-wall carbon nanotubes and “ropes” of single-wall carbon nanotubes. The purification process removes the extraneous carbon as well as metal-containing residual catalyst particles. The process employs steps including a gas-phase oxidation of the amorphous carbon and subsequent liquid-phase reaction of a halogen-containing acid with the metal-containing species. Optionally, the single-wall carbon nanotube material may be annealed dry or in the presence of moisture.

Abstract: A gas-phase method for producing high yields of single-wall carbon nanotubes with high purity and homogeneity is disclosed. The method involves using preformed metal catalyst clusters to initiate and grow single-wall carbon nanotubes. In one embodiment, multi-metallic catalyst precursors are used to facilitate the metal catalyst cluster formation. The catalyst clusters are grown to the desired size before mixing with a carbon-containing feedstock at a temperature and pressure sufficient to initiate and form single-wall carbon nanotubes. The method also involves using small fullerenes and preformed sections of single-wall carbon nanotubes, either derivatized or underivatized, as seed molecules for expediting the growth and increasing the yield of single-wall carbon nanotubes. The multi-metallic catalyst precursors and the seed molecules may be introduced into the reactor by means of a supercritical fluid. In addition the seed molecules may be introduced into the reactor via an aerosol or smoke.

Abstract: A gas-phase method for producing high yields of single-wall carbon nanotubes with high purity and homogeneity is disclosed. The method involves using preformed metal catalyst clusters to initiate and grow single-wall carbon nanotubes. In one embodiment, multi-metallic catalyst precursors are used to facilitate the metal catalyst cluster formation. The catalyst clusters are grown to the desired size before mixing with a carbon-containing feedstock at a temperature and pressure sufficient to initiate and form single-wall carbon nanotubes. The method also involves using small fullerenes and preformed sections of single-wall carbon nanotubes, either derivatized or underivatized, as seed molecules for expediting the growth and increasing the yield of single-wall carbon nanotubes. The multi-metallic catalyst precursors and the seed molecules may be introduced into the reactor by means of a supercritical fluid. In addition the seed molecules may be introduced into the reactor via an aerosol or smoke.

Abstract: The present invention is directed to a method of producing diamond films through the thermal dissociation of molecular chlorine into atomic chlorine in a heated graphite heat exchanger at temperatures of from about 1,100.degree. C. to about 1,800.degree. C. The atomic chlorine is subsequently rapidly mixed with molecular hydrogen and carbon-containing species downstream. Atomic hydrogen and the carbon precursors are produced through rapid hydrogen abstraction reactions of atomic chlorine with molecular hydrogen and hydrocarbons at the point where they mix. The mixed gases then flow across a heated substrate, where diamond is deposited as a film. Diamond deposits have been confirmed by Raman spectroscopy.

Abstract: The present invention is directed to a method for depositing diamond films and particles on a variety of substrates by flowing a gas or gas mixture capable of supplying (1) carbon, (2) hydrogen, (3) a halogen and, preferably, (4) a chalcogen through a reactor over the substrate material. The reactant gases may be premixed with an inert gas in order to keep the overall gas mixture composition low in volume percent of carbon and rich in hydrogen. Pre-treatment of the reactant gases to a high energy state is not required as it is in most prior art processes for chemical vapor deposition of diamond. Since pretreatment is not required, the process may be applied to substrates of virtually any desired size, shape or configuration.

Abstract: The present invention is directed to a method for depositing diamond films and particles on a variety of substrates by flowing a gas or gas mixture capable of supplying (1) carbon, (2) hydrogen and (3) a halogen through a reactor over the substrate material. The reactant gases may be pre-mixed with an inert gas in order to keep the overall gas mixture composition low in volume percent of carbon and rich in hydrogen. Pre-treatment of the reactant gases to a high energy state is not required as it is in most prior art processes for chemical vapor deposition of diamond. Since pre-treatment is not required, the process may be applied to substrates of virtually any desired size, shape or configuration.The reactant gas mixture preferably is passed through a reactor, a first portion of which is heated to a temperature of from about 400.degree. C. to about 920.degree. C. and more preferably from about 800.degree. C. to about 920.degree. C.

Abstract: Method and apparatus for accurately and instantaneously determining the thermodynamic temperature of remote objects by continuous determination of the emissivity, the reflectivity, and optical constants, as well as the apparent or brightness temperature of the sample with a single instrument. The emissivity measurement is preferably made by a complex polarimeter including a laser that generates polarized light, which is reflected from the sample into a detector system. The detector system includes a beamsplitter, polarization analyzers, and four detectors to measure independently the four Stokes vectors of the reflected radiation. The same detectors, or a separate detector in the same instrument, is used to measure brightness temperature. Thus, the instrument is capable of measuring both the change in polarization upon reflection as well as the degree of depolarization and hence diffuseness.