Abstract: Systems and methods for treating a fluid by passing fluid through a treatment structure, the fluid containing undesirable living things, the treatment structure containing electrically conductive nanomaterial with silver, flowing an electric current in the fluid in the treatment structure via the electrically conductive nanomaterial with silver or silver material to kill undesirable living things in the treatment structure, and killing undesirable things in the treatment structure.

Abstract: A device which converts mechanical deformation in electrical current, these mechanical deformations are generated as a result of liquid pressure over a part of the device. This device is integrated within an implantable lead and inserted into the cardiovascular system of a patient. The purpose of the device is to charge a battery which stores energy for various uses of other implantable devices.

Abstract: Compositions include a multi-walled nanotube including metal nanoparticles. The metal nanoparticles are bound to the multi-walled nanotube through functional groups on a surface of the multi-walled nanotube.

Abstract: A nanocomposite, comprising single-wall and/or multi-wall one-dimensional nanomaterials, and at least one nanooxide of at least one transition metal, said nanooxide filling said nanotubes and covering their walls. A process for preparing such a nanocomposite and an optical limiting device comprising such a nanocomposite in suspension in a medium that is transparent to visible and infrared radiation are disclosed.

Abstract: Provided is a continuous method and apparatus of purifying carbon nanotubes. The continuous method and apparatus of purifying carbon nanotubes is characterized in a first purifying step for injecting a carbon nanotube liquid mixture containing an oxidizer into a purifying reactor under a sub-critical water or supercritical water condition at a pressure of 50 to 400 atm and a temperature of 100 to 600° C. to obtain a purified product, thereby removing amorphous carbon and producing the carbon nanotube product.

Abstract: Disclosed herein is a sequential functionalization methodology for the covalent modification of nanotubes with between one and four repeat units of a polymer. Covalent attachment of oligomer units to the surface of nanotubes results in oligomer units forming an organic sheath around the nanotubes, polymer-functionalized-nanotubes (P-NTs). P-NTs possess chemical functionality identical to that of the functionalizing polymer, and thus provide nanoscale scaffolds which may be readily dispersed within a monomer solution and participate in the polymerization reaction to form a polymer-nanotube/polymer composite. Formation of polymer in the presence of P-NTs leads to a uniform dispersion of nanotubes within the polymer matrix, in contrast to aggregated masses of nanotubes in the case of pristine-NTs.

Abstract: The present invention provides a method of forming a self-assembly fullerene array on the surface of a substrate, comprising the following steps: (1) providing a substrate; (2) pre-annealing the substrate at a temperature ranging from 200° C. to 1200° C. in a vacuum system; and (3) providing powdered fullerene nanoparticles and depositing them on the surface of the substrate by means of physical vapor deposition technology in the vacuum system, so as to form a self-assembly fullerene array on the surface of the substrate. The present invention also provides a fullerene embedded substrate prepared therefrom, which has excellent field emission properties and can be used as a field emitter for any field emission displays. Finally, the present invention provides a fullerene embedded substrate prepared therefrom, which can be used to substitute for semiconductor carbides as optoelectronic devices and high-temperature, high-power, or high-frequency electric devices.

Abstract: Processes for manufacturing a thin film composite membrane comprising multi-walled carbon nanotubes include contacting under interfacial polymerization conditions an organic solution comprising a polyacid halide and carbon nanotubes with an aqueous solution comprising a polyamine to form a thin film composite membrane on a surface of a porous base membrane, wherein the organic solution additionally comprises a saturated cyclic C5-C20 hydrocarbon solvent.

Abstract: Certain spin-coatable liquids and application techniques are described, which can be used to form nanotube films or fabrics of controlled properties. A spin-coatable liquid for formation of a nanotube film includes a liquid medium containing a controlled concentration of purified nanotubes, wherein the controlled concentration is sufficient to form a nanotube fabric or film of preselected density and uniformity, and wherein the spin-coatable liquid comprises less than 1×1018 atoms/cm3 of metal impurities. The spin-coatable liquid is substantially free of particle impurities having a diameter of greater than about 500 nm.

Abstract: A porous catalyst includes at least one noble nano-metal particle, an oxide for forming porous structures, and a carrier material for supporting the oxide and the at least one noble nano-metal particle. The porous catalyst shows a large electrochemical surface area and a highly conductive ability. Further, the noble nano-metal particles are separated on the oxides uniformly, and the oxide of the catalyst forms a porous structure to provide a large electrochemical surface area. The porous catalyst provides excellent proton/electron transfer ability and increases the reaction rate.

Abstract: Dispersing agent of MWCNTs and the method for preparation of homogeneous MWCNTs dispersion are disclosed. Acid yellow 9(4-amino-1-1?-azobenzene-3,4?-disulfonic acid, AY) is a good agent for multi-walled carbon nanotubes (MWCNTs). MWCNTs dispersed in AY solution was remained stable about three months and even remained stable after centrifugation at 10000 rpm for 30 min. Using MWCNTs/AY dispersion, thin-films were prepared on indium tin oxide coated glass electrode and glassy carbon electrode. Further, dried firms of MWCNTs/AY were subjected to electropolymerization in 0.1 M H2SO4 solution. Adsorbed AY molecules on MWCNTs get polymerized and then yield a polymer-MWCNTs nanocomposite film on electrode surface so as to modify properties of the electrode.

Abstract: Internally calibrated pH and other analyte sensors based on redox agents provide more accurate results when the redox active reference agent is in a constant chemical environment, yet separated from the solution being analyzed in such a way as to maintain electrical contact with the sample. Room temperature ionic liquids (RTIL) can be used to achieve these results when used as a salt bridge between the reference material and the sample being analyzed. The RTIL provides the constant chemical environment and ionic strength for the redox active material (RAM) and provides an electrolytic layer that limits or eliminates direct chemical interaction with the sample. A broad range of RAMs can be employed in a variety of configurations in such “Analyte Insensitive Electrode” devices.

Abstract: The hydrogen-oxygen generating electrode plate using a carbon nano tube includes a carbon nano tube (CNT); a carbon (C); NiO; NaTaO3; and a catalyst. The method for manufacturing a hydrogen and oxygen generating electrode plate using a carbon nano tube, includes a step S1 for grinding into high-density powders; a step S2 for uniformly mixing carbon nano tube powder, carbon powder, NiO powder, NaTaO3 powder and catalyst and forming a mixture having a high distribution degree; a step S3 for inputting the mixture into a mold and pressing the same and forming a pressing forming object; and a step S4 for plasticity-forming the pressing forming object in a vacuum plasticity furnace.

Abstract: Composite structures of carbon nanotubes (CNTs) and metal carbides include a helical nanotube/carbide composite fiber, and a film. The composite fiber was prepared by pulling/twisting carbon nanotubes from an array of nanotubes to form an as-spun fiber and soaking it a metal precursor solution, and then heating it under a reducing atmosphere with a carbon source. The composite fiber had a higher tensile strength, a higher conductivity, and a higher tensile modulus than the as-spun fiber. A composite structure in the form of parallel ribbons of aligned carbon nanotubes embedded in a film of NbC showed an enhanced conductivity along the CNT axial direction, and improved superconducting properties. The enhanced upper critical field of NbC/CNT suggested that the inclusion of CNTs in the NbC matrix reduced the coherence length of the NbC. Nanomechanical testing also demonstrated the potential for enhanced fracture toughness of NbC/CNT composites.

Abstract: A method for making a polymer composite comprises mixing, a thermosetting polymer precursor, and 0.01 to 30 wt % of a derivatized nanoparticle based on the total weight of the polymer composite, the derivatized nanoparticle including functional groups comprising carboxy, epoxy, ether, ketone, amine, hydroxy, alkoxy, alkyl, aryl, aralkyl, alkaryl, lactone, functionalized polymeric or oligomeric groups, or a combination comprising at least one of the forgoing functional groups.

Abstract: Disclosed is a composition containing carbon nanotubes which meets all of the following conditions (1) to (4). (1) When observed via transmission electron microscopy, at least 50 out of every 100 carbon nanotubes are double-walled carbon nanotubes. (2) The carbon nanotubes have an average outer diameter in the range of 1.0 to 3.0 nm. (3) During thermogravimetric analysis under atmosphere at a temperature increase rate of 10° C./minute, a high temperature combustion peak is at 700 to 850° C., and the relationship between low temperature weight loss (TG(L)) and high temperature weight loss (TG(H)) is TG(H)/(TG(L)+TG(H))?0.75. (4) The composition containing carbon nanotubes has a volume resistance value between 1.0×10?2 ?·cm and 1.0×10?4 ?·cm, inclusive. The disclosed composition containing carbon nanotubes primarily has double-walled carbon nanotubes with high electrical conductivity and high heat resistance.

Abstract: A combination of MWNTs (herein, MWNTs have more than 2 walls) and DWNTs significantly improves the mechanical properties of polymer nanocomposites. A small amount of DWNTs reinforcement (<1 wt. %) significantly improves the flexural strength of epoxy matrix nanocomposites. A same or similar amount of MWNTs reinforcement significantly improves the flexural modulus (stiffness) of epoxy matrix nanocomposites. Both flexural strength and flexural modulus of the MWNTs and DWNTs-coreinforced epoxy nanocomposites are further improved compared with same amount of either DWNTs or MWNTs-reinforced epoxy nanocomposites. In this epoxy/DWNTs/MWNTs nanocomposite system, SWNTs may also work instead of DWNTs. Besides epoxy, other thermoset polymers may also work.

Abstract: A method of removing metal impurities from carbon nanotubes includes treating carbon nanotubes with distilled bromine in a substantially oxygen- and water-free atmosphere and then removing the distilled bromine from the carbon nanotubes. Purified carbon nanotubes having an iron content from about 2.5 to about 3.5 by weight that are substantially free of derivatization at the ends and defect sites are made available via this method.

Abstract: A nanocomposite comprises a nanostructure, and a copolymer adsorbed to the nanostructure and containing at least one ionic monomer unit and a different monomer unit from the ionic monomer unit; the ionic monomer unit selected from the group consisting of a zwitterionic monomer unit and a cationic monomer unit which are represented by the following formula (1): (in the formula (1), R1, R2, and R3 each independently represent any one of a hydrogen atom and a monovalent organic group having 1 to 20 carbon atoms, Y1 represents any one of a carbonyl group and an arylene group, Y2 represents any one of —O— and —NH—, n is 0 or 1, R4 represents a divalent organic group having 1 to 20 carbon atoms, and X represents any one of a zwitterionic group and a cationic group).

Abstract: Methods and devices relating to a radiation detector comprising of a gas chamber having a cathode plate and a substrate separated by a gap. An array of nano-tips deposited on the substrate that forms an anode structure for electron charge collection. An external power source in communication with the cathode plate and the substrate, wherein the external power source is capable of generating a plurality of regions and each region includes an electric field near each nano-tip of the array of the nano-tips that results in initiating a radiation induced controlled discharge of electrons and ions from at least one gas or at least one gas mixture. Finally, the plurality of regions include multiple generated electric fields near tips of the array of nano-tips such as CNTs, that communicatively create a conductive path between the cathode plate and the substrate, the radiation detector is capable of determining at least one radiation property.

Abstract: An apparatus for making a carbon nanotube composite structure includes a supply unit, a wrapping unit, and a collecting unit. The supply unit is configured to supply a linear structure. The wrapping unit includes a drive mechanism, a hollow rotating shaft, and a face plate. The drive mechanism is mounted on a first end of the hollow rotating shaft to drive the hollow rotating shaft. The face plate is fixed on a second end of the hollow rotating shaft and loads a carbon nanotube array with a growing substrate. The carbon nanotube array forms a carbon nanotube structure. The wrapping unit winds the carbon nanotube structure around the linear structure. The collecting unit pulls the linear structure and collects the carbon nanotube composite wire structure.

Abstract: Disclosed are an intermediate transfer belt for use in a laser printer, a fax machine and a copier, and a production method thereof. Specifically, an intermediate transfer belt including silicone modified polyimide resin and a production method thereof are provided, thereby realizing a monolayer intermediate transfer belt having excellent electrical properties, water repellency and heat dissipation properties and good mechanical strength. Further, even without the additional use of an adhesive layer for adhesion to a fluorine resin layer and fluorine resin, the intermediate transfer belt can exhibit satisfactory properties, and process efficiency can be maximized.

Abstract: A polymer-carbon nanotube composite film is provided for use as a sensor for detecting chemical vapors. The composite film is formed by coating perpendicularly-aligned carbon nanotubes with a polymer selected from poly(vinyl acetate), poly(isoprene), or blends thereof. The sensor may be formed by attaching at least two electrodes to the polymer-carbon nanotube composite film. The sensor may be used in any applications where the sensor is capable of detecting a change in conductivity in the composite.

Abstract: The present invention relates to a process for preparing catalyst composition for the synthesis of carbon nanotube with high yields using the spray pyrolysis method. More particularly, this invention relates to a process for preparing catalyst composition for the synthesis of carbon nanotube comprising the steps of i) dissolving multi-component metal precursors of catalyst composition in de-ionized water; ii) spraying obtained catalytic metal precursor solution into the high temperature reactor by gas atomization method; iii) forming the catalyst composition powder by pyrolysis of gas atomized material; and iv) obtaining the catalyst composition powder, wherein said catalyst composition comprises i) main catalyst selected from Fe or Co, ii) Al, iii) optional co-catalyst at least one selected from Ni, Cu, Sn, Mo, Cr, Mn, V, W, Ti, Si, Zr or Y, iv) inactive support of Mg. Further, the catalyst composition prepared by this invention has a very low apparent density of 0.01˜0.

Abstract: Methods and compositions for removing a contaminant from its environment. The method includes forming a magnetic composition comprising the contaminant and an amphiphilic substance, and applying a magnetic field to the magnetic composition so as to separate the magnetic composition from the environment. One composition includes a micelle array confined in a magnetic mesoporous framework. Another composition is formed by adhering an amphiphilic material comprising functional surface groups to a contaminant, then interacting a magnetic material with the functional surface groups of the amphiphilic material. In various versions, the contaminant can be a hydrophobic organic compound, or a fullerene-related nanoparticle. The methods can also be used to purify hydrophobic organic compounds or fullerene-related nanoparticles.

Abstract: A method is provided for functionalizing nanoscale fibers including reacting a plurality of nanoscale fibers with at least one epoxide monomer to chemically bond the at least one epoxide monomer to surfaces of the nanoscale fibers to form functionalized nanoscale fibers. Functionalized nanoscale fibers and nanoscale fiber films are also provided.

Abstract: An improved oil composition is disclosed. The oil composition includes a base oil comprising a hydrocarbon, the base oil having a base thermal conductivity. The oil composition also includes a first additive comprising a plurality of derivatized first additive nanoparticles dispersed within the base oil to form a modified oil having a modified thermal conductivity, wherein the modified thermal conductivity is greater than the base thermal conductivity. Alternately, an improved oil composition includes a base oil comprising a hydrocarbon and a first additive comprising a plurality of derivatized first additive nanoparticles dispersed within the base oil to form a modified oil comprising a stabilized suspension of the derivatized first additive nanoparticles in the base oil.

Abstract: Methods of making elastomeric nanocomposites with improved nanoparticle dispersion in the elastomer are described. The method includes the use of liquid form additives such as oils, plasticizers and/or solvents as dispersing agents to disperse nanoparticles into elastomers. Also described are articles such as downhole elements including the elastomeric nanocomposites made by the methods described herein.

Abstract: A cathode material for fluoride-based conversion electrodes includes a matrix of graphite nanocarbon containing a dispersion of alkali metal ions, fluoride ions and metal nanoparticles with maximum particle sizes of 20 nm. Further there is provides a method for such cathode material that includes heating a metal and an organic compound during a single thermal treatment step until the organic compound is decomposed; and adding an alkali metal fluoride either before or after the thermal treatment step to the organic compound. Finally, there is provided a method of making an alkali metal ion battery, that includes utilizing the aforesaid cathode material for a fluoride-based conversion electrode in the battery.

Abstract: Provided are a conductive polymer-carbon nanotube composite including a carbon nanotube and a conductive polymer filled therein, and a method of manufacturing the same. The conductive polymer-carbon nanotube composite where a conductive polymer is filled in a carbon nanotube is manufactured by introducing a monomer of the conductive polymer into the carbon nanotube using a supercritical fluid technique and polymerizing the monomer. The conductive polymer-carbon nanotube composite is a novel nano-structure material which can overcome limitations that conventional materials may have, and thus can be applied to various applications such as sensors, electrode materials, nanoelectronic materials, etc.

Abstract: A composition comprising: at least one porous carbon monolith, such as a carbon aerogel, comprising internal pores, and at least one nanomaterial, such as carbon nanotubes, disposed uniformly throughout the internal pores. The nanomaterial can be disposed in the middle of the monolith. In addition, a method for making a monolithic solid with both high surface area and good bulk electrical conductivity is provided. A porous substrate having a thickness of 100 microns or more and comprising macropores throughout its thickness is prepared. At least one catalyst is deposited inside the porous substrate. Subsequently, chemical vapor deposition is used to uniformly deposit a nanomaterial in the macropores throughout the thickness of the porous substrate. Applications include electrical energy storage, such as batteries and capacitors, and hydrogen storage.

Abstract: The invention relates to decontaminating composites, and methods, compositions, and kits comprising the same. In some aspects, the invention relates to a decontaminating composite, comprising a perhydrolase associated with a carbon nanotube, that is useful for producing peracids.

Abstract: Nanoelectronic devices for the detection and quantification of biomolecules are provided. In certain embodiments, the devices are configured to detect and measure blood glucose levels. Also provided are methods of fabricating nanoelectronic devices for the detection of biomolecules.

Abstract: A method comprising patterning a substrate to form exposed regions of the substrate sized to deter entangled growth of carbon nanotubes thereon and growing vertically aligned nanotubes on the exposed regions of the substrate.

Abstract: The invention provides high efficient dye-sensitized solar cells using tio2-carbon nano tube (MWCNT) nanocomposite. More particularly, the invention provides TiO2-MWCNT nanocomposites prepared by hydrothermal route which result in higher efficiency of the dye sensitized solar cell.

Abstract: The invention relates to a planar or shaped textile material comprising or constituted of fibers, at least part of the fibers being coated with a hydrolytically condensed inorganic/organic hybrid material having single-walled or multi-walled carbon nanotubes which are embedded therein, optionally covalently bound thereto. The carbon nanotubes are preferably functionalized, especially with carboxylic acid groups or sulfanilic acid groups. The textile material is suitable for producing protective clothing, barrier materials or the like. The invention further relates to the use of the above-defined hybrid material as a coating material which imparts stain-resistance and/or antimicrobial properties to the coated substrate.

Abstract: A carbon nanohorn (CNH) is oxidized to make an opening in the side of the CNH. A substance to be included, e.g., a metal, is introduced through the opening. The inclusion substance is moved to a tip part of the carbon nanohorn through heat treatment in vacuum or an inert gas. The CNH is further heat treated in an atmosphere containing oxygen in a low concentration to remove the carbon layer in the tip through catalysis of the inclusion substance. This exposes the inclusion substance. If the inclusion substance is a metal which is not moved to a tip part by the heat treatment in vacuum or an inert gas, the carbon part surrounding the fine catalyst particle is specifically burned by a heat treatment in an low oxygen concentration atmosphere, while utilizing the catalysis. Thus, the fine catalyst particle is fixed to the tip part of the CNH.

Abstract: Improved photovoltaic devices and methods are disclosed. In one embodiment, an exemplary photovoltaic device includes a semiconductor layer and a light-responsive layer (which can be made, for example, of a semiconductor material) which form a junction, such as a p-n junction. The light-responsive layer can include a plurality of carbon nanostructures, such as carbon nanotubes, located therein. In many cases, the carbon nanostructures can provide a conductive pathway within the light-responsive layer. In other embodiments, exemplary photovoltaic devices include semiconductor nanostructures, which can take a variety of forms, in addition to the carbon nanostructures. Further embodiments include a wide variety of other configurations and features. Methods of fabricating photovoltaic devices are also disclosed.

Abstract: Disclosed are a method for producing a carbon nanotube (CNT) whereby, in the local synthesis of CNTs, a high resolution, a low cost, easiness in production and mass production capability can be established at the same time; and a two-dimensionally patterned CNT obtained thereby.

Abstract: Drilling, drill-in and completion fluids containing nanoparticles for use in hydrocarbon drilling and recovery processes and methods related thereto are provided. The fluids also include a dual acting shield agent that shields the nanoparticles and also acts as a viscosifier. The fluids can be used in various types of hydrocarbon drilling and recovery processes, such as drilling, drill in, completion, and the like.

Abstract: The present invention relates to a composite fiber containing a thermoplastic polymeric matrix comprising a polyetherketoneketone (PEKK) in which multi-walled nanotubes, especially carbon nanotubes, are dispersed. It also relates to a process for manufacturing this composite fiber and to the uses thereof.

Abstract: Disclosed are a method for preparing a nanoparticle by using a carbon nanotube, and the nanoparticle prepared by the method. In the disclosed method, by using a carbon nanotube having a physically solid structure and a chemically solid bond, a powder particle made of metal, polymer, ceramic or the like is milled to a nano-size. Also, the nanoparticle prepared by the method has a small size and includes the carbon nanotube. Thus, when the method is applied to a highly oxidative metal, the nanoparticle can be applied to related fields requiring ignitability such as solid fuel, gunpowder, and the like. Also, the carbon nanotube has good mechanical properties and electrical conductivity, and thus can be applied to the related products.

Abstract: The present disclosure relates to a structure comprising 1. an electrically conductive substrate having carbon nanotubes grown thereon; 2. a cured polymeric fill matrix comprising at least one latent photoacid generator embedded around the carbon nanotubes but allowing tips of the carbon nanotubes to be exposed; 3. a layer of patterned and cured photosensitive dielectric material on the cured polymeric fill matrix, wherein tips of the carbon nanotubes are exposed within the patterns; and 4. an electrically conductive material filled into the interconnect pattern and in contact with the exposed tips of the carbon nanotubes; and to methods of making the structure and using the structure to measure the electrical characteristics of carbon nanotubes.

Abstract: The present invention provides fabrics that have unique mechanical, chemical, electrical, and thermal properties. The fabrics comprise layers of woven, knit or felted fibers, yarns or tow. Interstitially synthesized nanotubes, such as single-walled or multi-walled carbon nanotubes, enhance the fabric's antiballistic properties. These nanotubes may also insulate, semi-conduct or super-conduct electrical charges, or provide enhanced thermal properties of these fabrics which can be layered to form unique garments or structures.

Abstract: Ultralong carbon nanotubes can be formed by placing a secondary chamber within a reactor chamber to restrict a flow to provide a laminar flow. Inner shells can be successively extracted from multi-walled carbon nanotubes (MWNTs) such as by applying a lateral force to an elongated tubular sidewall at a location between its two ends. The extracted shells can have varying electrical and mechanical properties that can be used to create useful materials, electrical devices, and mechanical devices.

Abstract: According to one embodiment, a method is disclosed for manufacturing a nonvolatile memory device. The nonvolatile memory device includes a memory cell connected to a first interconnect and a second interconnect. The method can include forming a first electrode film on the first interconnect. The method can include forming a layer including a plurality of carbon nanotubes dispersed inside an insulator on the first electrode film. At least one carbon nanotube of the plurality of carbon nanotubes is exposed from a surface of the insulator. The method can include forming a second electrode film on the layer. In addition, the method can include forming a second interconnect on the second electrode film.

Abstract: According to one embodiment, a nonvolatile memory device includes a memory cell connected to a first interconnect and a second interconnect. The memory cell includes a plurality of layers. The plurality of layers includes a carbon-containing memory layer sandwiched between a first electrode film and a second electrode film and a carbon-containing barrier layer provided at least one of between the first electrode film and the memory layer and between the second electrode film and the memory layer. The barrier layer has lower electrical resistivity than the memory layer.

Abstract: A carbon nanotube-polymer composite includes a polymer continuous phase having at least a first polymer, and a plurality of carbon nanotubes dispersed in the polymer continuous phase. The carbon nanotubes are non-functionalized nanotubes. The carbon nanotubes are between 0.05 and 40 weight % of the composite. At least 98% of the carbon nanotubes are not involved in nanotube bundles.

Abstract: The present disclosure relates to the present disclosure relates to a method of fabricating an aligned polymer containing a bonded substrate and related compositions. The method involved placing a polymer in solution which is capable of alignment wherein the polymer is also bound to a selected substrate. This may then be followed by placing the polymer solution in an electrochemical cell wherein the polymer solution is in contact with at least one electrode and applying an electric field/voltage to the polymer solution and generating a pH gradient wherein the polymer and bonded substrate positions at the isoelectric point of the polymer in solution.

Abstract: Dispersible single-walled and multi-walled carbon nanotubes (CNTs) are prepared by dissolving surfactants in water to form a solution; adding carbon nanotubes to the solution to form a mixture; sonicating and agitating the mixture to form a carbon-nanotube/water dispersion; centrifuging the dispersion to remove un-dispersed carbon nanotubes and impurities; repeatedly freezing and heating the CNT dispersion; and, sublimating water in the CNT dispersion by freezing and evacuating the dispersion to obtain carbon nanotubes coated with surfactant. The carbon nanotubes prepared by the method of the invention are dry, amphiphilic, and surfactant-coated powders that can be dispersed in both aqueous and organic solvents to form stable and uniform dispersions having a high concentration of carbon nanotubes.