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Showing papers on "Carbon nanotube published in 2004"


Journal ArticleDOI
TL;DR: Arc-synthesized single-walled carbon nanotubes have been purified through preparative electrophoresis in agarose gel and glass bead matrixes and promise to be interesting nanomaterials in their own right.
Abstract: Arc-synthesized single-walled carbon nanotubes have been purified through preparative electrophoresis in agarose gel and glass bead matrixes. Two major impurities were isolated: fluorescent carbon and short tubular carbon. Analysis of these two classes of impurities was done. The methods described may be readily extended to the separation of other water-soluble nanoparticles. The separated fluorescent carbon and short tubule carbon species promise to be interesting nanomaterials in their own right.

3,357 citations


Journal ArticleDOI
27 Aug 2004-Science
TL;DR: Characteristics of the fabrication of ultrathin, transparent, optically homogeneous, electrically conducting films of pure single-walled carbon nanotubes indicate broad applicability of the films for electrical coupling in photonic devices.
Abstract: We describe a simple process for the fabrication of ultrathin, transparent, optically homogeneous, electrically conducting films of pure single-walled carbon nanotubes and the transfer of those films to various substrates. For equivalent sheet resistance, the films exhibit optical transmittance comparable to that of commercial indium tin oxide in the visible spectrum, but far superior transmittance in the technologically relevant 2- to 5-micrometer infrared spectral band. These characteristics indicate broad applicability of the films for electrical coupling in photonic devices. In an example application, the films are used to construct an electric field-activated optical modulator, which constitutes an optical analog to the nanotube-based field effect transistor.

2,958 citations


Journal ArticleDOI
19 Nov 2004-Science
TL;DR: In this article, the authors demonstrate the efficient chemical vapor deposition synthesis of single-walled carbon nanotubes where the activity and lifetime of the catalysts are enhanced by water.
Abstract: We demonstrate the efficient chemical vapor deposition synthesis of single-walled carbon nanotubes where the activity and lifetime of the catalysts are enhanced by water. Water-stimulated enhanced catalytic activity results in massive growth of superdense and vertically aligned nanotube forests with heights up to 2.5 millimeters that can be easily separated from the catalysts, providing nanotube material with carbon purity above 99.98%. Moreover, patterned, highly organized intrinsic nanotube structures were successfully fabricated. The water-assisted synthesis method addresses many critical problems that currently plague carbon nanotube synthesis.

2,405 citations


Journal ArticleDOI
TL;DR: In this paper, the absorption properties of CNT/crystalline Fe nanocomposites have been investigated and it was shown that the absorption property is due to the confinement of crystalline Fe in carbon nanoshells, deriving mainly from magnetic rather than electric effects.
Abstract: CNT/crystalline Fe nanocomposites (see Figure) have excellent microwave-absorption characteristics. This absorption property is shown to result from the confinement of crystalline Fe in carbon nanoshells, deriving mainly from magnetic rather than electric effects-the complex permittivity and permeability depend both on the shape and phase of the CNT/Fe nanocapsulates.

1,780 citations


Journal ArticleDOI
19 Nov 2004-Science
TL;DR: By introducing twist during spinning of multiwalled carbon nanotubes from nanotube forests to make multi-ply, torque-stabilized yarns, this work achieves yarn strengths greater than 460 megapascals, nearly as tough as fibers used for bulletproof vests.
Abstract: By introducing twist during spinning of multiwalled carbon nanotubes from nanotube forests to make multi-ply, torque-stabilized yarns, we achieve yarn strengths greater than 460 megapascals. These yarns deform hysteretically over large strain ranges, reversibly providing up to 48% energy damping, and are nearly as tough as fibers used for bulletproof vests. Unlike ordinary fibers and yarns, these nanotube yarns are not degraded in strength by overhand knotting. They also retain their strength and flexibility after heating in air at 450°C for an hour or when immersed in liquid nitrogen. High creep resistance and high electrical conductivity are observed and are retained after polymer infiltration, which substantially increases yarn strength.

1,653 citations


Journal ArticleDOI
TL;DR: Carbon nanotubes are unique tubular structures of nanometer diameter and large length/diameter ratio as mentioned in this paper, which can be metallic or semiconducting depending on their structural parameters.
Abstract: Carbon nanotubes are unique tubular structures of nanometer diameter and large length/diameter ratio. The nanotubes may consist of one up to tens and hundreds of concentric shells of carbons with adjacent shells separation of ∼0.34 nm. The carbon network of the shells is closely related to the honeycomb arrangement of the carbon atoms in the graphite sheets. The amazing mechanical and electronic properties of the nanotubes stem in their quasi-one-dimensional (1D) structure and the graphite-like arrangement of the carbon atoms in the shells. Thus, the nanotubes have high Young’s modulus and tensile strength, which makes them preferable for composite materials with improved mechanical properties. The nanotubes can be metallic or semiconducting depending on their structural parameters. This opens the ways for application of the nanotubes as central elements in electronic devices including field-effect transistors (FET), single-electron transistors and rectifying diodes. Possibilities for using of the nanotubes as high-capacity hydrogen storage media were also considered. This report is intended to summarize some of the major achievements in the field of the carbon nanotube research both experimental and theoretical in connection with the possible industrial applications of the nanotubes.

1,610 citations


Journal ArticleDOI
19 Aug 2004-Nature
TL;DR: Observations in situ of defect formation in single graphene layers by high-resolution TEM are reported and are expected to be of use when engineering the properties of carbon nanostructures for specific device applications.
Abstract: Atomic-scale defects in graphene layers alter the physical and chemical properties of carbon nanostructures. Theoretical predictions have recently shown that energetic particles such as electrons and ions can induce polymorphic atomic defects in graphene layers as a result of knock-on atom displacements. However, the number of experimental reports on these defects is limited. The graphite network in single-walled carbon nanotubes has been visualized by transmission electron microscopy (TEM) and their chiral indices have been determined. But the methods used require a long image acquisition time and intensive numerical treatments after observations to find an 'average' image, which prevents the accurate detection and investigation of defect structures. Here we report observations in situ of defect formation in single graphene layers by high-resolution TEM. The observed structures are expected to be of use when engineering the properties of carbon nanostructures for specific device applications.

1,517 citations


Journal ArticleDOI
TL;DR: In this article, a carbon nanotube transistors with channel lengths exceeding 300 microns have been fabricated, where the carrier transport is diffusive and the channel resistance dominates the transport.
Abstract: Semiconducting carbon nanotube transistors with channel lengths exceeding 300 microns have been fabricated. In these long transistors, carrier transport is diffusive and the channel resistance dominates the transport. Transport characteristics are used to extract the field-effect mobility (79 000 cm2/Vs) and estimate the intrinsic mobility (>100 000 cm2/Vs) at room temperature. These values exceed those for all known semiconductors, which bodes well for application of nanotubes in high-speed transistors, single- and few-electron memories, and chemical/biochemical sensors.

1,510 citations


Journal ArticleDOI
TL;DR: In this article, double-wall carbon nanotubes (DWCNTs) and an epoxy matrix were produced by a standard calandering technique and a very good dispersion of both DWCNT and carbon black (CB) was observed.

1,455 citations


Journal ArticleDOI
29 Jan 2004-Nature
TL;DR: Time-resolved, high-resolution in situ transmission electron microscope observations of the formation of carbon nanofibres from methane decomposition over supported nickel nanocrystals show that metallic step edges act as spatiotemporal dynamic growth sites and may be important for understanding other types of catalytic reactions and nanomaterial syntheses.
Abstract: The synthesis of carbon nanotubes with predefined structure and functionality plays a central role in the field of nanotechnology1,2, whereas the inhibition of carbon growth is needed to prevent a breakdown of industrial catalysts for hydrogen and synthesis gas production3. The growth of carbon nanotubes and nanofibres has therefore been widely studied4,5,6,7,8,9,10. Recent advances in in situ techniques now open up the possibility of studying gas–solid interactions at the atomic level11,12. Here we present time-resolved, high-resolution in situ transmission electron microscope observations of the formation of carbon nanofibres from methane decomposition over supported nickel nanocrystals. Carbon nanofibres are observed to develop through a reaction-induced reshaping of the nickel nanocrystals. Specifically, the nucleation and growth of graphene layers are found to be assisted by a dynamic formation and restructuring of mono-atomic step edges at the nickel surface. Density-functional theory calculations indicate that the observations are consistent with a growth mechanism involving surface diffusion of carbon and nickel atoms. The finding that metallic step edges act as spatiotemporal dynamic growth sites may be important for understanding other types of catalytic reactions and nanomaterial syntheses.

1,357 citations


Journal ArticleDOI
09 Apr 2004-Science
TL;DR: In this article, the authors used a rotating spindle to spin fibers and ribbons of carbon nanotubes directly from the chemical vapor deposition (CVD) synthesis zone of a furnace using a liquid source of carbon and an iron nanocatalyst.
Abstract: Many routes have been developed for the synthesis of carbon nanotubes, but their assembly into continuous fibers has been achieved only through postprocessing methods. We spun fibers and ribbons of carbon nanotubes directly from the chemical vapor deposition (CVD) synthesis zone of a furnace using a liquid source of carbon and an iron nanocatalyst. This process was realized through the appropriate choice of reactants, control of the reaction conditions, and continuous withdrawal of the product with a rotating spindle used in various geometries. This direct spinning from a CVD reaction zone is extendable to other types of fiber and to the spin coating of rotating objects in general.

Journal ArticleDOI
TL;DR: In this paper, the interactions between various functionalized carbon nanotubes and several types of human cancer cells are explored. And they have shown that these can be derivatized in a way that enables attachment of small molecules and of proteins, the latter through a novel noncovalent association.
Abstract: The interactions between various functionalized carbon nanotubes and several types of human cancer cells are explored. We have prepared modified nanotubes and have shown that these can be derivatized in a way that enables attachment of small molecules and of proteins, the latter through a novel noncovalent association. The functionalized carbon nanotubes enter nonadherent human cancer cells as well as adherent cell lines (CHO and 3T3) and by themselves are not toxic. While the fluoresceinated protein streptavidin (MW approximately 60 kD) by itself does not enter cells, it readily enters cells when complexed to a nanotube-biotin transporter and exhibits dose-dependent cytotoxicity. The uptake pathway is consistent with adsorption-mediated endocytosis. The use of carbon nanotubes as molecular transporters could be exploited for various cargos. The biocompatibility and unique physical, electrical, optical, and mechanical properties of nanotubes provide the basis for new classes of materials for drug, protein, and gene delivery applications.

Journal ArticleDOI
02 Jan 2004-Science
TL;DR: An array of aligned carbon nanotubes (CNTs) was incorporated across a polymer film to form a well-ordered nanoporous membrane structure, which was confirmed by electron microscopy, anisotropic electrical conductivity, gas flow, and ionic transport studies.
Abstract: An array of aligned carbon nanotubes (CNTs) was incorporated across a polymer film to form a well-ordered nanoporous membrane structure This membrane structure was confirmed by electron microscopy, anisotropic electrical conductivity, gas flow, and ionic transport studies The measured nitrogen permeance was consistent with the flux calculated by Knudsen diffusion through nanometer-scale tubes of the observed microstructure Data on Ru(NH3)6(3+) transport across the membrane in aqueous solution also indicated transport through aligned CNT cores of the observed microstructure The lengths of the nanotubes within the polymer film were reduced by selective electrochemical oxidation, allowing for tunable pore lengths Oxidative trimming processes resulted in carboxylate end groups that were readily functionalized at the entrance to each CNT inner core Membranes with CNT tips that were functionalized with biotin showed a reduction in Ru(NH3)6(3+) flux by a factor of 15 when bound with streptavidin, thereby demonstrating the ability to gate molecular transport through CNT cores for potential applications in chemical separations and sensing

Journal ArticleDOI
TL;DR: A review of recent studies conducted on carbon nanotube/polymer composites can be found in this paper, where various processing methods for producing these nanocomposites are discussed, in particular melt mixing, solution processing and in-situ polymerization.
Abstract: This paper reviews recent studies conducted on carbon nanotube/polymer composites. Carbon nanotubes are promising new materials for blending with polymers with potential to obtain low-weight nanocomposites of extraordinary mechanical, electrical, thermal and multifunctional properties. The size scale, aspect ratio and properties of nanotubes provide advantages in a variety of applications, including electrostatically dissipative materials; advanced materials with combined stiffness, strength and impact for aerospace or sporting goods; composite mirrors; automotive parts that require electrostatic painting and automotive components with enhanced mechanical properties. The various processing methods for producing these nanocomposites are discussed, in particular melt mixing, solution processing and in-situ polymerization. Some key results are summarized, relating to the mechanical, electrical, thermal, optical and surface properties. Finally, the challenges for the future are discussed in terms of processing, characterization, nanotube availability, nanotube tailoring, and the mechanisms governing the behavior of these remarkable nanoscale composites. Polym. Compos. 25:630–645, 2004. © 2004 Society of Plastics Engineers.

Journal ArticleDOI
TL;DR: In this article, single-walled carbon nanotube (SWNT)/poly(methyl methacrylate) (PMMA) nanocomposites were prepared via coagulation method providing uniform dispersion of the nanotubes in the polymer matrix.
Abstract: Single-walled carbon nanotube (SWNT)/poly(methyl methacrylate) (PMMA) nanocomposites were prepared via our coagulation method providing uniform dispersion of the nanotubes in the polymer matrix. Optical microscopy, Raman imaging, and SEM were employed to determine the dispersion of nanotube at different length scales. The linear viscoelastic behavior and electrical conductivity of these nanocomposites were investigated. At low frequencies, G‘ becomes almost independent of the frequency as nanotube loading increases, suggesting an onset of solidlike behavior in these nanocomposites. By plotting G‘ vs nanotube loading and fitting with a power law function, the rheological threshold of these nanocomposites is ∼0.12 wt %. This rheological threshold is smaller than the percolation threshold of electrical conductivity, ∼0.39 wt %. This difference in the percolation threshold is understood in terms of the smaller nanotube−nanotube distance required for electrical conductivity as compared to that required to impe...

Journal ArticleDOI
TL;DR: In this paper, a uniform single-walled carbon nanotube networks of varying densities have been fabricated at room temperature by a vacuum filtration method, and measurements of the sheet conductance as a function of the network density show 2D percolation behavior.
Abstract: Ultrathin, uniform single-walled carbon nanotube networks of varying densities have been fabricated at room temperature by a vacuum filtration method. Measurements of the sheet conductance as a function of nanotube network density show 2D percolation behavior. In addition, the network transparency in the visible spectral range was examined and the results are in agreement with a standard thin-film model: fits to the standard theory indicate U ac ) Udc for transmission measurements at 550 nm. Transmission measurements also indicate the usefulness of nanotube network films as a transparent, conductive coating. Avenues for improvement of the network conductance are discussed.

Journal ArticleDOI
25 Jun 2004-Science
TL;DR: In this article, Dzenis discusses the process of nanofiber electrospinning, in which continuous threads of polymers or ceramic precursors are emitted from a liquid surface as thin jets.
Abstract: Carbon nanotubes are attracting a lot of attention as the building blocks of nanotechnology. But nanotubes are difficult to align and process into useful materials. In his Perspective, Dzenis discusses the process of nanofiber electrospinning, in which continuous threads of polymers or ceramic precursors are emitted from a liquid surface as thin jets. These continuous nanofibers may offer an alternative for new nanotechnology applications.

Journal ArticleDOI
TL;DR: Transmission electron microscopy analysis was performed at the microscopy facility of the Institute of Biomedical Problems and was cofinanced by CNRS, R=gion Alsace, Louis Pasteur University, and the Association de la Recherche pour le Cancer.
Abstract: [*] Dipl.-Chem. D. Pantarotto, Prof. M. Prato Dipartimento di Scienze Farmaceutiche Universit di Trieste 34127 Trieste (Italy) Fax: (+39)040-5272 E-mail: prato@univ.trieste.it Dipl.-Chem. R. Singh, Dipl.-Chem. D. McCarthy, Dr. K. Kostarelos Centre for Drug Delivery Research and Electron Microscopy Unit The School of Pharmacy University of London London WC1N 1AX (United Kingdom) Fax: (+39)207-7535942 E-mail: kostas.kostarelos@ulsop.ac.uk Dipl.-Chem. D. Pantarotto, Dr. J.-P. Briand, Dr. A. Bianco Institut de Biologie Mol=culaire et Cellulaire UPR9021 CNRS Immunologie et Chimie Th=rapeutiques 67084 Strasbourg (France) Fax: (+33)388-610-680 E-mail: A.Bianco@ibmc.u-strasbg.fr Dr. M. Erhardt Institut de Biologie Mol=culaire des Plantes 67084 Strasbourg (France) [**] This work was supported by the Centre National de la Recherche Scientifique (CNRS), Universit di Trieste, and Ministero dell’Istruzione, dell’ Universit e della Ricerca (MIUR; cofin 2002, prot. 2002032171). Transmission electron microscopy (TEM) analysis was performed at the microscopy facility of the Institute of Biomedical Problems and was cofinanced by CNRS, R=gion Alsace, Louis Pasteur University, and the Association de la Recherche pour le Cancer. The authors wish to acknowledge C. D. Partidos for helpful and stimulating discussions. We thank Mr. Claudio Gamboz (Centro Servizi Polivalenti di Ateneo (CSPA), Universit di Trieste) for his great help with the TEM measurements. Supporting information for this article is available on the WWW under http://www.angewandte.org or from the author. Communications

Journal ArticleDOI
TL;DR: Functionalised carbon nanotubes are able to cross the cell membrane and to accumulate in the cytoplasm or reach the nucleus without being toxic for the cell up to 10 µM.

Journal ArticleDOI
TL;DR: With glucose oxidase (GOx) as an enzyme model, a GC or carbon fiber microelectrode-based biosensor is constructed that responds even more sensitively to glucose than the GC/GOx electrode modified by Pt nanoparticles or CNTs alone.
Abstract: Platinum nanoparticles with a diameter of 2-3 nm were prepared and used in combination with single-wall carbon nanotubes (SWCNTs) for fabricating electrochemical sensors with remarkably improved sensitivity toward hydrogen peroxide. Nafion, a perfluorosulfonated polymer, was used to solubilize SWCNTs and also displayed strong interactions with Pt nanoparticles to form a network that connected Pt nanoparticles to the electrode surface. TEM and AFM micrographs illustrated the deposition of Pt nanoparticles on carbon nanotubes whereas cyclic voltammetry confirmed an electrical contact through SWCNTs between Pt nanoparticles and the glassy carbon (GC) or carbon fiber backing. With glucose oxidase (GOx) as an enzyme model, we constructed a GC or carbon fiber microelectrode-based biosensor that responds even more sensitively to glucose than the GC/GOx electrode modified by Pt nanoparticles or CNTs alone. The response time and detection limit (S/N = 3) of this biosensor was determined to be 3 s and 0.5 microM, respectively.

Book
01 Jan 2004
TL;DR: In this article, the basic properties and properties of Nanomaterials are discussed. But they do not cover the application of nanophotonics in the medical field, except for carbon nanotubes.
Abstract: Fundamentals of Nanomaterials Zero-Dimensional Nanomaterials (Nanoparticles) One-Dimensional Nanomaterials (Nanowires, Nanofibers, Nanotubes, Nanocables) Two-Dimensional Nanomaterials (Thin Films) Special Nanomaterials (e.g., Carbon Nanotubes) Synthesis, Properties, and Applications of Nanomaterials.

Journal ArticleDOI
TL;DR: This work demonstrates that the uniform dispersion of 1–5 vol.% of carbon nanotubes in a thermoplastic elastomer yields nanocomposites that can store and subsequently release, through remote means, up to 50% more recovery stress than the pristine resin.
Abstract: Stimuli-responsive (active) materials undergo large-scale shape or property changes in response to an external stimulus such as stress, temperature, light or pH1,2. Technological uses range from durable, shape-recovery eye-glass frames, to temperature-sensitive switches, to the generation of stress to induce mechanical motion3,4,5,6,7,8,9. Here, we demonstrate that the uniform dispersion of 1–5 vol.% of carbon nanotubes in a thermoplastic elastomer yields nanocomposites that can store and subsequently release, through remote means, up to 50% more recovery stress than the pristine resin. The anisotropic nanotubes increase the rubbery modulus by a factor of 2 to 5 (for 1–5 vol.%) and improve shape fixity by enhancing strain-induced crystallization. Non-radiative decay of infrared photons absorbed by the nanotubes raises the internal temperature, melting strain-induced polymer crystallites (which act as physical crosslinks that secure the deformed shape) and remotely trigger the release of the stored strain energy. Comparable effects occur for electrically induced actuation associated with Joule heating of the matrix when a current is passed through the conductive percolative network of the nanotubes within the resin. This unique combination of properties, directly arising from the nanocomposite morphology, demonstrates new opportunities for the design and fabrication of stimuli-responsive polymers, which are otherwise not available in one material system.

Journal ArticleDOI
TL;DR: The synthesis and successful testing of solution-phase, near-infrared sensors, with β-D-glucose sensing as a model system, using single-walled carbon nanotubes that modulate their emission in response to the adsorption of specific biomolecules are reported.
Abstract: Molecular detection using near-infrared light between 0.9 and 1.3 eV has important biomedical applications because of greater tissue penetration and reduced auto-fluorescent background in thick tissue or whole-blood media. Carbon nanotubes have a tunable near-infrared emission that responds to changes in the local dielectric function but remains stable to permanent photobleaching. In this work, we report the synthesis and successful testing of solution-phase, near-infrared sensors, with beta-D-glucose sensing as a model system, using single-walled carbon nanotubes that modulate their emission in response to the adsorption of specific biomolecules. New types of non-covalent functionalization using electron-withdrawing molecules are shown to provide sites for transferring electrons in and out of the nanotube. We also show two distinct mechanisms of signal transduction-fluorescence quenching and charge transfer. The results demonstrate new opportunities for nanoparticle optical sensors that operate in strongly absorbing media of relevance to medicine or biology.

Journal ArticleDOI
04 Jun 2004-Science
TL;DR: This family of molecularly engineered graphite with a one-dimensional tubular shape and a chemically accessible surface constitutes an important step toward molecular electronics.
Abstract: An amphiphilic hexa-peri-hexabenzocoronene self-assembles to form a π-electronic, discrete nanotubular object. The object is characterized by an aspect ratio greater than 1000 and has a uniform, 14-nanometer-wide, open-ended hollow space, which is an order of magnitude larger than those of carbon nanotubes. The wall is 3 nanometers thick and consists of helical arrays of the π-stacked graphene molecule, whose exterior and interior surfaces are covered by hydrophilic triethylene glycol chains. The graphitic nanotube is redox active, and a single piece of the nanotube across 180-nanometer-gap electrodes shows, upon oxidation, an electrical conductivity of 2.5 megohms at 285 kelvin. This family of molecularly engineered graphite with a one-dimensional tubular shape and a chemically accessible surface constitutes an important step toward molecular electronics.

Journal ArticleDOI
TL;DR: In this article, the state of the art in carbon nanotube/polymer-matrix composites for mechanical reinforcement is reviewed with emphasis on recent advances in CNT composite toughness.
Abstract: The state of research into carbon nanotube/polymer–matrix composites for mechanical reinforcement is critically reviewed with emphasis on recent advances in CNT composite toughness. Particular interest is also given to interfacial bonding of carbon nanotubes to polymer matrices as it applies to stress transfer from the matrix to the CNT. Potential topics of oncoming focus are highlighted.

Book
12 Mar 2004
TL;DR: In this article, the authors present a character and correlation table of the Raman Spectra of single-walled carbon nanotubes with respect to the properties of room temperature, room-temperature conductance, and vibrational properties.
Abstract: Preface. 1 Introduction. 2 Structure and Symmetry. 2.1 Structure of Carbon Nanotubes. 2.2 Experiments. 2.3 Symmetry of Single-walled Carbon Nanotubes. 2.3.1 Symmetry Operations. 2.3.2 Symmetry-based Quantum Numbers. 2.3.3 Irreducible representations. 2.3.4 Projection Operators. 2.3.5 Phonon Symmetries in Carbon Nanotubes. 2.4 Summary. 3 Electronic Properties of Carbon Nanotubes. 3.1 Graphene. 3.1.1 Tight-binding Description of Graphene. 3.2 Zone-folding Approximation. 3.3 Electronic Density of States. 3.3.1 Experimental Verifications of the DOS. 3.4 Beyond Zone Folding - Curvature Effects. 3.4.1 Secondary Gaps in Metallic Nanotubes. 3.4.2 Rehybridization of the sigma and pi States. 3.5 Nanotube Bundles. 3.5.1 Low-energy Properties. 3.5.2 Visible Energy Range. 3.6 Summary. 4 Optical P roperties. 4.1 Absorption and Emission. 4.1.1 Selection Rules and Depolarization. 4.2 Spectra of Isolated Tubes. 4.3 Photoluminescence Excitation - (n1, n2) Assignment. 4.4 4-A-diameter Nanotubes. 4.5 Bundles of Nanotubes. 4.6 Excited-state Carrier Dynamics. 4.7 Summary. 5 Electronic Transport. 5.1 Room-temperature Conductance of Nanotubes. 5.2 Electron Scattering. 5.3 Coulomb Blockade. 5.4 Luttinger Liquid. 5.5 Summary. 6 Elastic Properties. 6.1 Continuum Model of Isolated Nanotubes. 6.1.1 Ab-initio, Tight-binding, and Force-constants Calculations. 6.2 Pressure Dependence of the Phonon Frequencies. 6.3 Micro-mechanical Manipulations. 6.4 Summary. 7 Raman Scattering. 7.1 Raman Basics and Selection Rules. 7.2 Tensor Invariants. 7.2.1 Polarized Measurements. 7.3 Raman Measurements at Large Phonon q. 7.4 Double Resonant Raman Scattering. 7.5 Summary. 8 Vibrational Properties. 8.1 Introduction. 8.2 Radial Breathing Mode. 8.2.1 The RBM in Isolated and Bundled Nanotubes. 8.2.2 Double-walled Nanotubes. 8.3 The Defect-induced D Mode. 8.3.1 The D Mode in Graphite. 8.3.2 The D Mode in Carbon Nanotubes. 8.4 Symmetry of the Raman Modes. 8.5 High-energy Vibrations. 8.5.1 Raman and Infrared Spectroscopy. 8.5.2 Metallic Nanotubes. 8.5.3 Single- and Double-resonance Interpretation. 8.6 Summary. 8.7 What we Can Learn from the Raman Spectra of Single-walled Carbon Nanotubes. Appendix A: Character and Correlation Tables of Graphene. Appendix B: Raman Intensities in Unoriented Systems. Appendix C: Fundamental Constants. Bibliography. Index.

Journal ArticleDOI
TL;DR: In this article, the current status of available methodologies for the aqueous dispersion and solubilization of carbon nanotubes, discuss the results on modifications of carbon-nanotubes with various biological and bioactive species, and highlight some of the recent achievements in the fabrication and evaluation of carbonnanotube-based bioanalytical devices.
Abstract: Bioapplications of carbon nanotubes have been predicted and explored ever since the discovery of these one-dimensional carbon allotropes. Indeed, carbon nanotubes have many interesting and unique properties potentially useful in a variety of biological and biomedical systems and devices. Significant progress has been made in the effort to overcome some of the fundamental and technical barriers toward bioapplications, especially on issues concerning the aqueous solubility and biocompatibility of carbon nanotubes and on the design and fabrication of prototype biosensors. In this article we take a comprehensive look at the advances in this fast-moving and exciting research field. We review the current status of available methodologies for the aqueous dispersion and solubilization of carbon nanotubes, discuss the results on modifications of carbon nanotubes with various biological and bioactive species, and highlight some of the recent achievements in the fabrication and evaluation of carbon nanotube-based bioanalytical devices.

Journal ArticleDOI
TL;DR: The uptake of pristine single-walled carbon nanotube into macrophage-like cells has been studied using the nanotubes' intrinsic near-infrared fluorescence to occur through phagocytosis.
Abstract: The uptake of pristine single-walled carbon nanotubes into macrophage-like cells has been studied using the nanotubes' intrinsic near-infrared fluorescence. Macrophage samples that have been incubated in growth media containing suspended single-walled nanotubes show characteristic nanotube fluorescence spectra. The fluorescence intensities increase smoothly with incubation time and external nanotube concentration. Near-infrared fluorescence microscopy at wavelengths above 1100 nm provides high contrast images indicating localization of nanotubes in numerous intracellular vesicles. Nanotube uptake appears to occur through phagocytosis. Population growth of macrophage cultures is unaffected by exposure to single-walled nanotube concentrations of ca. 4 μg/mL for up to 96 h.

Journal ArticleDOI
TL;DR: In this article, a simple formula for the thermal conductivity enhancement in carbon nanotube composites is presented by incorporating the interface thermal resistance with an effective medium approach, which predicts that a large interface thermal sensitivity across the nanotubes-matrix interface causes a significant degradation in the thermal performance.
Abstract: A simple formula for the thermal conductivity enhancement in carbon nanotube composites is presented by incorporating the interface thermal resistance with an effective medium approach. This model well describes the thermal conductivity enhancement observed recently in nanotube suspensions. In particular, this simple formula predicts that a large interface thermal resistance across the nanotube-matrix interface causes a significant degradation in the thermal conductivity enhancement, even for the case with ultrahigh intrinsic thermal conductivity and aspect ratio of the carbon nanotubes embedded.

Journal ArticleDOI
TL;DR: Although laboratory studies indicated that with sufficient agitation, unrefined SWCNT material can release fine particles into the air, concentrations generated while handling material in the field were very low, and estimates of the airborne concen-tration of nanotube material generated during handling suggest that concentrations were lower than 53μg/m3 in all cases.
Abstract: Carbon nanotubes represent a relatively recently discovered allotrope of carbon that exhibits unique properties. While commercial interest in the material is leading to the development of mass production and handling facilities, little is known of the risk associated with exposure. In a two-part study, preliminary investigations have been carried out into the potential exposure routes and toxicity of single-walled carbon nanotube material (SWCNT)--a specific form of the allotrope. The material is characterized by bundles of fibrous carbon molecules that may be a few nanometers in diameter, but micrometers in length. The two production processes investigated use-transition metal catalysts, leading to the inclusion of nanometer-scale metallic particles within unrefined SWCNT material. A laboratory-based study was undertaken to evaluate the physical nature of the aerosol formed from SWCNT during mechanical agitation. This was complemented by a field study in which airborne and dermal exposure to SWCNT was investigated while handling unrefined material. Although laboratory studies indicated that with sufficient agitation, unrefined SWCNT material can release fine particles into the air, concentrations generated while handling material in the field were very low. Estimates of the airborne concentration of nanotube material generated during handling suggest that concentrations were lower than 53 microg/m(3) in all cases. Glove deposits of SWCNT during handling were estimated at between 0.2 mg and 6 mg per hand.