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Sample records for carbon nanotube micro-fin

  1. Experimental Study on Cooling Heat Transfer of Supercritical Carbon Dioxide Inside Horizontal Micro-Fin Tubes

    Science.gov (United States)

    Kuwahara, Ken; Higashiiu, Shinya; Ito, Daisuke; Koyama, Shigeru

    This paper deals with the experimental study on cooling heat transfer of supercritical carbon dioxide inside micro-fin tubes. The geometrical parameters in micro-fin tubes used in the present study are 6.02 mm in outer diameter, 4.76 mm to 5.11 mm in average inner diameter, 0.15 mm to 0.24 mm in fin height, 5 to 25 in helix angle, 46 to 52 in number of fins and 1.4 to 2.3 in area expansion ratio. Heat transfer coefficients were measured at 8-10 MPa in pressure, 360-690 kg/(m2•s) in mass velocity and 20-75 °C in CO2 temperature. The measured heat transfer coefficients of micro-fin tubes were 1.4 to 2 times higher than those of the smooth tube having 4.42 in inner diameter. The predicted heat transfer coefficients using the correlation equation, which was developed for single-phase turbulent fluid flow inside micro-fin-tubes, showed large deviations to the measured values. The new correlation to predict cooling heat transfer coefficient of supercritical carbon dioxide inside micro-fin tubes was developed taking into account the shape of fins based on experimental data empirically. This correlation equation agreed within ±20% of almost all of the experimental data.

  2. Carbon nanotube composite materials

    Energy Technology Data Exchange (ETDEWEB)

    O' Bryan, Gregory; Skinner, Jack L; Vance, Andrew; Yang, Elaine Lai; Zifer, Thomas

    2015-03-24

    A material consisting essentially of a vinyl thermoplastic polymer, un-functionalized carbon nanotubes and hydroxylated carbon nanotubes dissolved in a solvent. Un-functionalized carbon nanotube concentrations up to 30 wt % and hydroxylated carbon nanotube concentrations up to 40 wt % can be used with even small concentrations of each (less than 2 wt %) useful in producing enhanced conductivity properties of formed thin films.

  3. Carbon nanotube nanoelectrode arrays

    Science.gov (United States)

    Ren, Zhifeng; Lin, Yuehe; Yantasee, Wassana; Liu, Guodong; Lu, Fang; Tu, Yi

    2008-11-18

    The present invention relates to microelectode arrays (MEAs), and more particularly to carbon nanotube nanoelectrode arrays (CNT-NEAs) for chemical and biological sensing, and methods of use. A nanoelectrode array includes a carbon nanotube material comprising an array of substantially linear carbon nanotubes each having a proximal end and a distal end, the proximal end of the carbon nanotubes are attached to a catalyst substrate material so as to form the array with a pre-determined site density, wherein the carbon nanotubes are aligned with respect to one another within the array; an electrically insulating layer on the surface of the carbon nanotube material, whereby the distal end of the carbon nanotubes extend beyond the electrically insulating layer; a second adhesive electrically insulating layer on the surface of the electrically insulating layer, whereby the distal end of the carbon nanotubes extend beyond the second adhesive electrically insulating layer; and a metal wire attached to the catalyst substrate material.

  4. Carbon nanotube quantum dots

    NARCIS (Netherlands)

    Sapmaz, S.

    2006-01-01

    Low temperature electron transport measurements on individual single wall carbon nanotubes are described in this thesis. Carbon nanotubes are small hollow cylinders made entirely out of carbon atoms. At low temperatures (below ~10 K) finite length nanotubes form quantum dots. Because of its small si

  5. Synthesis of carbon nanotubes.

    Science.gov (United States)

    Awasthi, Kalpana; Srivastava, Anchal; Srivastava, O N

    2005-10-01

    Carbon nanotubes play a fundamental role in the rapidly developing field of nanoscience and nanotechnology because of their unique properties and high potential for applications. In this article, the different synthesis methods of carbon nanotubes (both multi-walled and single-walled) are reviewed. From the industrial point of view, the chemical vapor deposition method has shown advantages over laser vaporization and electric arc discharge methods. This article also presents recent work in the controlled synthesis of carbon nanotubes with ordered architectures. Special carbon nanotube configurations, such as nanocoils, nanohorns, bamboo-shaped and carbon cylinder made up from carbon nanotubes are also discussed.

  6. Nanomechanics of carbon nanotubes.

    Science.gov (United States)

    Kis, Andras; Zettl, Alex

    2008-05-13

    Some of the most important potential applications of carbon nanotubes are related to their mechanical properties. Stiff sp2 bonds result in a Young's modulus close to that of diamond, while the relatively weak van der Waals interaction between the graphitic shells acts as a form of lubrication. Previous characterization of the mechanical properties of nanotubes includes a rich variety of experiments involving mechanical deformation of nanotubes using scanning probe microscopes. These results have led to promising prototypes of nanoelectromechanical devices such as high-performance nanomotors, switches and oscillators based on carbon nanotubes.

  7. Organic modification of carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The organic modification of carbon nanotubes is a novel research field being developed recently. In this article, the history and newest progress of organic modification of carbon nanotubes are reviewed from two aspects:organic covalent modification and organic noncovalent modification of carbon nanotubes. The preparation and properties of organic modified carbon nanotubes are discussed in detail. In addition, the prospective development of organic modification of carbon nanotubes is suggested.

  8. Carbon nanotube solar cells.

    Directory of Open Access Journals (Sweden)

    Colin Klinger

    Full Text Available We present proof-of-concept all-carbon solar cells. They are made of a photoactive side of predominantly semiconducting nanotubes for photoconversion and a counter electrode made of a natural mixture of carbon nanotubes or graphite, connected by a liquid electrolyte through a redox reaction. The cells do not require rare source materials such as In or Pt, nor high-grade semiconductor processing equipment, do not rely on dye for photoconversion and therefore do not bleach, and are easy to fabricate using a spray-paint technique. We observe that cells with a lower concentration of carbon nanotubes on the active semiconducting electrode perform better than cells with a higher concentration of nanotubes. This effect is contrary to the expectation that a larger number of nanotubes would lead to more photoconversion and therefore more power generation. We attribute this to the presence of metallic nanotubes that provide a short for photo-excited electrons, bypassing the load. We demonstrate optimization strategies that improve cell efficiency by orders of magnitude. Once it is possible to make semiconducting-only carbon nanotube films, that may provide the greatest efficiency improvement.

  9. Inkjet Printing of Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Ryan P. Tortorich

    2013-07-01

    Full Text Available In an attempt to give a brief introduction to carbon nanotube inkjet printing, this review paper discusses the issues that come along with preparing and printing carbon nanotube ink. Carbon nanotube inkjet printing is relatively new, but it has great potential for broad applications in flexible and printable electronics, transparent electrodes, electronic sensors, and so on due to its low cost and the extraordinary properties of carbon nanotubes. In addition to the formulation of carbon nanotube ink and its printing technologies, recent progress and achievements of carbon nanotube inkjet printing are reviewed in detail with brief discussion on the future outlook of the technology.

  10. Experiments with micro-fin tube in single phase

    Energy Technology Data Exchange (ETDEWEB)

    Copetti, J.B.; Macagnan, M.H.; De Souza, D.; Oliveski, R.D.C. [Universidade do Vale do Rio dos Sinos, Sao Leopoldo (Brazil). Department of Mechanical Engineering

    2004-12-01

    This work shows heat transfer and friction characteristics for water single-phase flow in micro-fin tubes. The analysis of thermal and hydraulic behavior from a laminar to a turbulent flow was carried out in an experimental setup with a 9.52 mm diameter micro-fin tube. The tube was wrapped up with an electrical resistance tape to supply a constant heat flux to its surface. Different operational conditions were considered in the heating tests. The inlet and outlet temperatures, differential wall temperatures along the tube, pressure drop and flow rate were measured. The relationships of heat flux and flow rate with heat transfer coefficient and pressure drop were analyzed. Under the same conditions, comparative experiments with an internally smooth tube were conducted. The micro-fin tube provides higher heat transfer performance than the smooth tube (in turbulent flow h{sub micro-fin}/h{sub smooth}=2.9). In spite of the increase in pressure drop ({delta}p{sub micro-fin}/{delta}p{sub smooth}=1.7) the heat transfer results were significantly higher (about 80%). This shows the advantages of this enhanced configuration in thermal performance related to conventional tubes. The smooth tube results were validated by the comparison with the Dittus-Boelter and Gnielinski correlations. For the micro-fin tube an empirical correlation to the heat transfer coefficient adjusted from the set of measured data is proposed. The values obtained are in conformity with experimental results. (author)

  11. Templated Growth of Carbon Nanotubes

    Science.gov (United States)

    Siochik Emilie J. (Inventor)

    2007-01-01

    A method of growing carbon nanotubes uses a synthesized mesoporous si lica template with approximately cylindrical pores being formed there in. The surfaces of the pores are coated with a carbon nanotube precu rsor, and the template with the surfaces of the pores so-coated is th en heated until the carbon nanotube precursor in each pore is convert ed to a carbon nanotube.

  12. Carbon nanotube junctions and devices

    NARCIS (Netherlands)

    Postma, H.W.Ch.

    2001-01-01

    In this thesis Postma presents transport experiments performed on individual single-wall carbon nanotubes. Carbon nanotubes are molecules entirely made of carbon atoms. The electronic properties are determined by the exact symmetry of the nanotube lattice, resulting in either metallic or semiconduct

  13. Carbon nanotubes for supercapacitor.

    Science.gov (United States)

    Pan, Hui; Li, Jianyi; Feng, Yuanping

    2010-01-05

    As an electrical energy storage device, supercapacitor finds attractive applications in consumer electronic products and alternative power source due to its higher energy density, fast discharge/charge time, low level of heating, safety, long-term operation stability, and no disposable parts. This work reviews the recent development of supercapacitor based on carbon nanotubes (CNTs) and their composites. The purpose is to give a comprehensive understanding of the advantages and disadvantages of carbon nanotubes-related supercapacitor materials and to find ways for the improvement in the performance of supercapacitor. We first discussed the effects of physical and chemical properties of pure carbon nanotubes, including size, purity, defect, shape, functionalization, and annealing, on the supercapacitance. The composites, including CNTs/oxide and CNTs/polymer, were further discussed to enhance the supercapacitance and keep the stability of the supercapacitor by optimally engineering the composition, particle size, and coverage.

  14. Carbon Nanotubes for Supercapacitor

    Directory of Open Access Journals (Sweden)

    Li Jianyi

    2010-01-01

    Full Text Available Abstract As an electrical energy storage device, supercapacitor finds attractive applications in consumer electronic products and alternative power source due to its higher energy density, fast discharge/charge time, low level of heating, safety, long-term operation stability, and no disposable parts. This work reviews the recent development of supercapacitor based on carbon nanotubes (CNTs and their composites. The purpose is to give a comprehensive understanding of the advantages and disadvantages of carbon nanotubes-related supercapacitor materials and to find ways for the improvement in the performance of supercapacitor. We first discussed the effects of physical and chemical properties of pure carbon nanotubes, including size, purity, defect, shape, functionalization, and annealing, on the supercapacitance. The composites, including CNTs/oxide and CNTs/polymer, were further discussed to enhance the supercapacitance and keep the stability of the supercapacitor by optimally engineering the composition, particle size, and coverage.

  15. Carbon nanotube filters

    Science.gov (United States)

    Srivastava, A.; Srivastava, O. N.; Talapatra, S.; Vajtai, R.; Ajayan, P. M.

    2004-09-01

    Over the past decade of nanotube research, a variety of organized nanotube architectures have been fabricated using chemical vapour deposition. The idea of using nanotube structures in separation technology has been proposed, but building macroscopic structures that have controlled geometric shapes, density and dimensions for specific applications still remains a challenge. Here we report the fabrication of freestanding monolithic uniform macroscopic hollow cylinders having radially aligned carbon nanotube walls, with diameters and lengths up to several centimetres. These cylindrical membranes are used as filters to demonstrate their utility in two important settings: the elimination of multiple components of heavy hydrocarbons from petroleum-a crucial step in post-distillation of crude oil-with a single-step filtering process, and the filtration of bacterial contaminants such as Escherichia coli or the nanometre-sized poliovirus (~25 nm) from water. These macro filters can be cleaned for repeated filtration through ultrasonication and autoclaving. The exceptional thermal and mechanical stability of nanotubes, and the high surface area, ease and cost-effective fabrication of the nanotube membranes may allow them to compete with ceramic- and polymer-based separation membranes used commercially.

  16. Carbon nanotubes for microelectronics?

    Science.gov (United States)

    Graham, Andrew P; Duesberg, Georg S; Seidel, Robert V; Liebau, Maik; Unger, Eugen; Pamler, Werner; Kreupl, Franz; Hoenlein, Wolfgang

    2005-04-01

    Despite all prophecies of its end, silicon-based microelectronics still follows Moore's Law and continues to develop rapidly. However, the inherent physical limits will eventually be reached. Carbon nanotubes offer the potential for further miniaturization as long as it is possible to selectively deposit them with defined properties.

  17. Nitrogen doping in carbon nanotubes.

    Science.gov (United States)

    Ewels, C P; Glerup, M

    2005-09-01

    Nitrogen doping of single and multi-walled carbon nanotubes is of great interest both fundamentally, to explore the effect of dopants on quasi-1D electrical conductors, and for applications such as field emission tips, lithium storage, composites and nanoelectronic devices. We present an extensive review of the current state of the art in nitrogen doping of carbon nanotubes, including synthesis techniques, and comparison with nitrogen doped carbon thin films and azofullerenes. Nitrogen doping significantly alters nanotube morphology, leading to compartmentalised 'bamboo' nanotube structures. We review spectroscopic studies of nitrogen dopants using techniques such as X-ray photoemission spectroscopy, electron energy loss spectroscopy and Raman studies, and associated theoretical models. We discuss the role of nanotube curvature and chirality (notably whether the nanotubes are metallic or semiconducting), and the effect of doping on nanotube surface chemistry. Finally we review the effect of nitrogen on the transport properties of carbon nanotubes, notably its ability to induce negative differential resistance in semiconducting tubes.

  18. The Toxicology of Carbon Nanotubes

    Science.gov (United States)

    Donaldson, Ken; Poland, Craig; Duffin, Rodger; Bonner, James

    2012-06-01

    1. Carbon nanotube structure, synthesis and applications C. Singh and W. Song; 2. The aerodynamic behaviour and pulmonary deposition of carbon nanotubes A. Buckley, R. Smith and R Maynard; 3. Utilising the concept of the biologically effective dose to define the particle and fibre hazards of carbon nanotubes K. Donaldson, R. Duffin, F. Murphy and C. Poland; 4. CNT, biopersistence and the fibre paradigm D. Warheit and M. DeLorme; 5. Length-dependent retention of fibres in the pleural space C. Poland, F. Murphy and K. Donaldson; 6. Experimental carcinogenicity of carbon nanotubes in the context of other fibres K. Unfried; 7. Fate and effects of carbon nanotubes following inhalation J. Ryman-Rasmussen, M. Andersen and J. Bonner; 8. Responses to pulmonary exposure to carbon nanotubes V. Castranova and R. Mercer; 9. Genotoxicity of carbon nanotubes R. Schins, C. Albrecht, K. Gerloff and D. van Berlo; 10. Carbon nanotube-cellular interactions; macrophages, epithelial and mesothelial cells V. Stone, M. Boyles, A. Kermanizadeh, J. Varet and H. Johnston; 11. Systemic health effects of carbon nanotubes following inhalation J. McDonald; 12. Dosimetry and metrology of carbon nanotubes L. Tran, L. MacCalman and R. Aitken; Index.

  19. Carbon Nanotube Purification and Functionalization

    Science.gov (United States)

    Lebron, Marisabel; Mintz, Eric; Smalley, Richard E.; Meador, Michael A.

    2003-01-01

    Carbon nanotubes have the potential to significantly enhance the mechanical, thermal, and electrical properties of polymers. However, dispersion of carbon nanotubes in a polymer matrix is hindered by the electrostatic forces that cause them to agglomerate. Chemical modification of the nanotubes is necessary to minimize these electrostatic forces and promote adhesion between the nanotubes and the polymer matrix. In a collaborative research program between Clark Atlanta University, Rice University, and NASA Glenn Research Center several approaches are being explored to chemically modify carbon nanotubes. The results of this research will be presented.

  20. Production of carbon nanotubes

    Science.gov (United States)

    Journet, C.; Bernier, P.

    Carbon nanostructures such as single-walled and multi-walled nanotubes (SWNTs and MWNTs) or graphitic polyhedral nanoparticles can be produced using various methods. Most of them are based on the sublimation of carbon under an inert atmosphere, such as the electric arc discharge process, the laser ablation method, or the solar technique. But chemical methods can also be used to synthesize these kinds of carbon materials: the catalytic decomposition of hydrocarbons, the production by electrolysis, the heat treatment of a polymer, the low temperature solid pyrolysis, or the in situ catalysis.

  1. Carbon nanotube network varactor

    Science.gov (United States)

    Generalov, A. A.; Anoshkin, I. V.; Erdmanis, M.; Lioubtchenko, D. V.; Ovchinnikov, V.; Nasibulin, A. G.; Räisänen, A. V.

    2015-01-01

    Microelectromechanical system (MEMS) varactors based on a freestanding layer of single-walled carbon nanotube (SWCNT) films were designed, fabricated and tested. The freestanding SWCNT film was employed as a movable upper patch in the parallel plate capacitor of the MEMS. The measurements of the SWCNT varactors show very high tunability, nearly 100%, of the capacitance with a low actuation voltage of 10 V. The functionality of the varactor is improved by implementing a flexible nanocellulose aerogel filling.

  2. Carbon Nanotube Thermoelectric Coolers

    Science.gov (United States)

    2015-02-06

    conductance. Inside thecentral section of the carbon nanotube, we obtained an impressive Peltier cooling 57 K down from the liquid nitrogentemperature. 15... trapped charges or dipoles) that occur either at the interface between the CNT and the gate dielectric (interface defects) or at some position within... liquid nitrogen temperature 77T  K up to hot 134 8T  K, or decreases from 77T  K down to about cold 20 6T  K, thus evidencing a strong

  3. Carbon nanotube biosensors

    OpenAIRE

    Tîlmaciu, Carmen-Mihaela; Morris, May C

    2015-01-01

    Nanomaterials possess unique features which make them particularly attractive for biosensing applications. In particular, carbon nanotubes (CNTs) can serve as scaffolds for immobilization of biomolecules at their surface, and combine several exceptional physical, chemical, electrical, and optical characteristics properties which make them one of the best suited materials for the transduction of signals associated with the recognition of analytes, metabolites, or disease biomarkers. Here we pr...

  4. From Carbon Nanotube Crystals to Carbon Nanotube Flowers

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhengjun; ZHAO Ye; ZHOU Ya

    2005-01-01

    We have investigated the very initial deposition stages of chemical vapor deposition (CVD) with ferrocene (Fe(C5H5)2) and xylene (C8H10) for growing carbon nanotubes, and made clear that the mechanism for the self-organization behaviors of nanotubes at different growth stages by this approach. For instance, the organization of nanotubes into flower-like structures at prolonged deposition is developed from the crystal-like structures formed at early growth stages, both of which are closely related to and determined by the very initial deposition stages of this CVD approach. Based on this approach, ways have been established to build up different architectures of carbon nanotubes, by controlling the initial deposition stages of the CVD process, with which we have realized the selective growth of self-organized carbon nanotube structures. This study provides a new idea for growing carbon nanotube architectures by CVD.

  5. Carbon Nanotubes Based Quantum Devices

    Science.gov (United States)

    Lu, Jian-Ping

    1999-01-01

    This document represents the final report for the NASA cooperative agreement which studied the application of carbon nanotubes. The accomplishments are reviewed: (1) Wrote a review article on carbon nanotubes and its potentials for applications in nanoscale quantum devices. (2) Extensive studies on the effects of structure deformation on nanotube electronic structure and energy band gaps. (3) Calculated the vibrational spectrum of nanotube rope and the effect of pressure. and (4) Investigate the properties of Li intercalated nanotube ropes and explore their potential for energy storage materials and battery applications. These studies have lead to four publications and seven abstracts in international conferences.

  6. Experimental Study on Condensation of Pure Refrigerants in Horizontal Micro-fin Tubes

    Science.gov (United States)

    Yonemoto, Ryuichiro; Koyama, Shigeru

    This paper presents the heat transfer and pressure drop correlations for condensation in micro-fin tubes. Experimental data for eleven micro-fin tubes with different fin dimensions were used, and the refrigerants tested were R22, R123 and R134a. The predicted results using new correlations show good agreement with experimental results within an absolute deviation of ±30%. Experimental results for the micro-fin tubes were also compared with previous correlations for micro-fin Tubes.

  7. Lithium interaction with carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Nalimova, V.A. [Moskovskij Gosudarstvennyj Univ., Moscow (Russian Federation). Khimicheskij Fakul`tet; Sklovsky, D.E. [Moskovskij Gosudarstvennyj Univ., Moscow (Russian Federation). Khimicheskij Fakul`tet; Bondarenko, G.N. [Topcheiv Institute of Petrochemical Synthesis, Leninsky Prospekt, 29, Moscow (Russian Federation); Alvergnat-Gaucher, H. [CRMD, CNRS, Universite d`Orleans, 1B rue de la Ferollerie, 45071, Orleans Cedex 02 (France); Bonnamy, S. [CRMD, CNRS, Universite d`Orleans, 1B rue de la Ferollerie, 45071, Orleans Cedex 02 (France); Beguin, F. [CRMD, CNRS, Universite d`Orleans, 1B rue de la Ferollerie, 45071, Orleans Cedex 02 (France)

    1997-05-01

    Lithium interaction with catalytic carbon nanotubes under high-pressure conditions was studied. A large amount of Li (2Li/C) reacted with the carbon nanotubes forming an intercalation compound (I{sub c}{proportional_to}4.1 A) which follows from X-ray diffraction and IR spectroscopy data. We cannot exclude also the possibility of insertion of a part of Li into the channel of the nanotubes. (orig.)

  8. Carbon nanotube Archimedes screws.

    Science.gov (United States)

    Oroszlány, László; Zólyomi, Viktor; Lambert, Colin J

    2010-12-28

    Recently, nanomechanical devices composed of a long stationary inner carbon nanotube and a shorter, slowly rotating outer tube have been fabricated. In this paper, we study the possibility of using such devices as nanoscale transducers of motion into electricity. When the outer tube is chiral, we show that such devices act like quantum Archimedes screws, which utilize mechanical energy to pump electrons between reservoirs. We calculate the pumped charge from one end of the inner tube to the other, driven by the rotation of a chiral outer nanotube. We show that the pumped charge can be greater than one electron per 360° rotation, and consequently, such a device operating with a rotational frequency of 10 MHz, for example, would deliver a current of ≈1 pAmp.

  9. Carbon Nanotubes and Modern Nanoagriculture

    KAUST Repository

    Bayoumi, Maged Fouad

    2015-01-27

    Since their discovery, carbon nanotubes have been prominent members of the nanomaterial family. Owing to their extraordinary physical, chemical, and mechanical properties, carbon nanotubes have been proven to be a useful tool in the field of plant science. They were frequently perceived to bring about valuable biotechnological and agricultural applications that still remain beyond experimental realization. An increasing number of studies have demonstrated the ability of carbon nanotubes to traverse different plant cell barriers. These studies, also, assessed the toxicity and environmental impacts of these nanomaterials. The knowledge provided by these studies is of practical and fundamental importance for diverse applications including intracellular labeling and imaging, genetic transformation, and for enhancing our knowledge of plant cell biology. Although different types of nanoparticles have been found to activate physiological processes in plants, carbon nanotubes received particular interest. Following addition to germination medium, carbon nanotubes enhanced root growth and elongation of some plants such as onion, cucumber and rye-grass. They, also, modulated the expression of some genes that are essential for cell division and plant development. In addition, multi-walled carbon nanotubes were evidenced to penetrate thick seed coats, stimulate germination, and to enhance growth of young tomato seedlings. Multi-walled carbon nanotubes can penetrate deeply into the root system and further distribute into the leaves and the fruits. In recent studies, carbon nanotubes were reported to be chemically entrapped into the structure of plant tracheary elements. This should activate studies in the fields of plant defense and wood engineering. Although, all of these effects on plant physiology and plant developmental biology have not been fully understood, the valuable findings promises more research activity in the near future toward complete scientific understanding of

  10. Studies of Carbon Nanotubes

    Science.gov (United States)

    Caneba, Gerard T.

    2005-01-01

    The fellowship experience for this summer for 2004 pertains to carbon nanotube coatings for various space-related applications. They involve the following projects: (a) EMI protection films from HiPco-polymers, and (b) Thermal protection nanosilica materials. EMI protection films are targeted to be eventually applied onto casings of laptop computers. These coatings are composites of electrically-conductive SWNTs and compatible polymers. The substrate polymer will be polycarbonate, since computer housings are typically made of carbon composites of this type of polymer. A new experimental copolymer was used last year to generate electrically-conductive and thermal films with HiPco at 50/50 wt/wt composition. This will be one of the possible formulations. Reference films will be base polycarbonate and neat HiPco onto polycarbonate films. Other coating materials that will be tried will be based on HiPco composites with commercial enamels (polyurethane, acrylic, polyester), which could be compatible with the polycarbonate substrate. Nanosilica fibers are planned for possible use as thermal protection tiles on the shuttle orbiter. Right now, microscale silica is used. Going to the nanoscale will increase the surface-volume-per-unit-area of radiative heat dissipation. Nanoscale carbon fibers/nanotubes can be used as templates for the generation of nanosilica. A sol-gel operation is employed for this purpose.

  11. Carbon Nanotubes for Space Applications

    Science.gov (United States)

    Meyyappan, Meyya

    2000-01-01

    The potential of nanotube technology for NASA missions is significant and is properly recognized by NASA management. Ames has done much pioneering research in the last five years on carbon nanotube growth, characterization, atomic force microscopy, sensor development and computational nanotechnology. NASA Johnson Space Center has focused on laser ablation production of nanotubes and composites development. These in-house efforts, along with strategic collaboration with academia and industry, are geared towards meeting the agency's mission requirements. This viewgraph presentation (including an explanation for each slide) outlines the research focus for Ames nanotechnology, including details on carbon nanotubes' properties, applications, and synthesis.

  12. Luminescence of carbon nanotube bulbs

    Institute of Scientific and Technical Information of China (English)

    LI ChuanGang; WU DeHai; WANG KunLin; WEI JinQuan; WEI BingQing; ZHU HongWei; WANG ZhiCheng; LUO JianBin; LIU WenJin; ZHENG MingXin

    2007-01-01

    Carbon nanotube (CNT) bulbs made of decimeter-scale double-walled carbon nanotube (DWCNT) strands and films were fabricated and their luminescence properties, including the lighting efficiency, voltage-current relation and thermal stability were investigated. The results show that the DWCNT bulb has a comparable spectrum of visible light with tungsten bulb and its average efficiency is 40% higher than that of a tungsten filament at the same temperature (1400-2300 K). The nanotube filaments show both resistance and thermal stability over a large temperature region. No obvious damage was found for a nanotube bulb illuminating at 2300 K for more than 24 hours in vacuum.

  13. Carbon Nanotube Biosensors

    Directory of Open Access Journals (Sweden)

    Carmen-Mihaela eTilmaciu

    2015-10-01

    Full Text Available Nanomaterials possess unique features which make them particularly attractive for biosensing applications. In particular Carbon Nanotubes (CNTs can serve as scaffolds for immobilization of biomolecules at their surface, and combine several exceptional physical, chemical, electrical and optical characteristics properties which make them one of the best suited materials for the transduction of signals associated with the recognition of analytes, metabolites or disease biomarkers. Here we provide a comprehensive review on these carbon nanostructures, in which we will describe their structural and physical properties, discuss functionalization and cellular uptake, biocompatibility and toxicity issues. We further review historical developments in the field of biosensors, and describe the different types of biosensors which have been developed over time, with specific focus on CNT-conjugates engineered for biosensing applications, and in particular detection of cancer biomarkers.

  14. Carbon nanotube biosensors

    Science.gov (United States)

    Tîlmaciu, Carmen-Mihaela; Morris, May C.

    2015-01-01

    Nanomaterials possess unique features which make them particularly attractive for biosensing applications. In particular, carbon nanotubes (CNTs) can serve as scaffolds for immobilization of biomolecules at their surface, and combine several exceptional physical, chemical, electrical, and optical characteristics properties which make them one of the best suited materials for the transduction of signals associated with the recognition of analytes, metabolites, or disease biomarkers. Here we provide a comprehensive review on these carbon nanostructures, in which we describe their structural and physical properties, functionalization and cellular uptake, biocompatibility, and toxicity issues. We further review historical developments in the field of biosensors, and describe the different types of biosensors which have been developed over time, with specific focus on CNT-conjugates engineered for biosensing applications, and in particular detection of cancer biomarkers. PMID:26579509

  15. Atomic transportation via carbon nanotubes.

    Science.gov (United States)

    Wang, Quan

    2009-01-01

    The transportation of helium atoms in a single-walled carbon nanotube is reported via molecular dynamics simulations. The efficiency of the atomic transportation is found to be dependent on the type of the applied loading and the loading rate as well as the temperature in the process. Simulations show the transportation is a result of the van der Waals force between the nanotube and the helium atoms through a kink propagation initiated in the nanotube.

  16. Method for synthesizing carbon nanotubes

    Science.gov (United States)

    Fan, Hongyou

    2012-09-04

    A method for preparing a precursor solution for synthesis of carbon nanomaterials, where a polar solvent is added to at least one block copolymer and at least one carbohydrate compound, and the precursor solution is processed using a self-assembly process and subsequent heating to form nanoporous carbon films, porous carbon nanotubes, and porous carbon nanoparticles.

  17. Carbon nanotubes: engineering biomedical applications.

    Science.gov (United States)

    Gomez-Gualdrón, Diego A; Burgos, Juan C; Yu, Jiamei; Balbuena, Perla B

    2011-01-01

    Carbon nanotubes (CNTs) are cylinder-shaped allotropic forms of carbon, most widely produced under chemical vapor deposition. They possess astounding chemical, electronic, mechanical, and optical properties. Being among the most promising materials in nanotechnology, they are also likely to revolutionize medicine. Among other biomedical applications, after proper functionalization carbon nanotubes can be transformed into sophisticated biosensing and biocompatible drug-delivery systems, for specific targeting and elimination of tumor cells. This chapter provides an introduction to the chemical and electronic structure and properties of single-walled carbon nanotubes, followed by a description of the main synthesis and post-synthesis methods. These sections allow the reader to become familiar with the specific characteristics of these materials and the manner in which these properties may be dependent on the specific synthesis and post-synthesis processes. The chapter ends with a review of the current biomedical applications of carbon nanotubes, highlighting successes and challenges.

  18. CFD Analysis for Optimum Thermal Design of Carbon Nanotube Based Micro-Channel Heatsink

    Directory of Open Access Journals (Sweden)

    M. Mahbub

    2011-10-01

    Full Text Available Carbon nanotube (CNT is considered as an ideal material for thermal management in electronic packaging because of its extraordinary high thermal conductivity. Fabricated onto a silicon substrate to form micro-channels, the CNT based cooling fins show high heat dissipation efficiency. A series of 2D and 3D CFD simulations have been carried out for CNT based micro-channel cooling architectures based on one and two dimensional fin array in this paper using COMSOL 4.0a software. Micro-channels are generally regarded as an effective method for the heat transfer in electronic products. The influence of various fluids, micro-fin structures, fluid velocity and heating powers on cooling effects have been simulated and compared in this study. Steady-state thermal stress analyses for the forced convection heat transfer are also performed to determine maximum allowable stress and deflections for the different types of cooling assembly.

  19. Functionalization of Carbon Nanotubes

    Science.gov (United States)

    Khare, Bishun N. (Inventor); Meyyappan, Meyya (Inventor)

    2009-01-01

    Method and system for functionalizing a collection of carbon nanotubes (CNTs). A selected precursor gas (e.g., H2 or F2 or CnHm) is irradiated to provide a cold plasma of selected target species particles, such as atomic H or F, in a first chamber. The target species particles are d irected toward an array of CNTs located in a second chamber while suppressing transport of ultraviolet radiation to the second chamber. A CNT array is functionalized with the target species particles, at or below room temperature, to a point of saturation, in an exposure time interval no longer than about 30 sec. *Discrimination against non-target species is provided by (i) use of a target species having a lifetime that is much greater than a lifetime of a non-target species and/or (2) use of an applied magnetic field to discriminate between charged particle trajectories for target species and for non-target species.

  20. Carbon Nanotube Electron Gun

    Science.gov (United States)

    Nguyen, Cattien V. (Inventor); Ribaya, Bryan P. (Inventor)

    2013-01-01

    An electron gun, an electron source for an electron gun, an extractor for an electron gun, and a respective method for producing the electron gun, the electron source and the extractor are disclosed. Embodiments provide an electron source utilizing a carbon nanotube (CNT) bonded to a substrate for increased stability, reliability, and durability. An extractor with an aperture in a conductive material is used to extract electrons from the electron source, where the aperture may substantially align with the CNT of the electron source when the extractor and electron source are mated to form the electron gun. The electron source and extractor may have alignment features for aligning the electron source and the extractor, thereby bringing the aperture and CNT into substantial alignment when assembled. The alignment features may provide and maintain this alignment during operation to improve the field emission characteristics and overall system stability of the electron gun.

  1. Carbon nanotube biconvex microcavities

    Science.gov (United States)

    Butt, Haider; Yetisen, Ali K.; Ahmed, Rajib; Yun, Seok Hyun; Dai, Qing

    2015-03-01

    Developing highly efficient microcavities with predictive narrow-band resonance frequencies using the least amount of material will allow the applications in nonlinear photonic devices. We have developed a microcavity array that comprised multi-walled carbon nanotubes (MWCNT) organized in a biconvex pattern. The finite element model allowed designing microcavity arrays with predictive transmission properties and assessing the effects of the microarray geometry. The microcavity array demonstrated negative index and produced high Q factors. 2-3 μm tall MWCNTs were patterned as biconvex microcavities, which were separated by 10 μm in an array. The microcavity was iridescent and had optical control over the diffracted elliptical patterns with a far-field pattern, whose properties were predicted by the model. It is anticipated that the MWCNT biconvex microcavities will have implications for the development of highly efficient lenses, metamaterial antennas, and photonic circuits.

  2. Enhanced Carbon Nanotube Ultracapacitors Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed innovation utilizes carbon nanotubes (CNTs) coated with pseudo-capacitive MnO2 material as nano-composite electrode and ionic electrolyte for the...

  3. Carbon nanotubes for coherent spintronics

    DEFF Research Database (Denmark)

    Kuemmeth, Ferdinand; Churchill, H O H; Herring, P K;

    2010-01-01

    Carbon nanotubes bridge the molecular and crystalline quantum worlds, and their extraordinary electronic, mechanical and optical properties have attracted enormous attention from a broad scientific community. We review the basic principles of fabricating spin-electronic devices based on individua...

  4. Molybdenum Disulfide Sheathed Carbon Nanotubes

    Institute of Scientific and Technical Information of China (English)

    Xu Chun SONG; Zhu De XU; Yi Fan ZHENG; Gui HAN; Bo LIU; Wei Xiang CHEN

    2004-01-01

    Single and double layered MoS2-coated multiwalled carbon nanotubes (MWCNs) were successfully prepared by pyrolyzing (NH4)2MoS4-coated multiwalled carbon nanotubes in an H2 atmosphere at 900℃. MoS2-coated MWCNs would be expected to have different tribological and mechanical properties compared to MoS2, so it may have potential applications in many fields.

  5. Selective functionalization of carbon nanotubes

    Science.gov (United States)

    Strano, Michael S. (Inventor); Usrey, Monica (Inventor); Barone, Paul (Inventor); Dyke, Christopher A. (Inventor); Tour, James M. (Inventor); Kittrell, W. Carter (Inventor); Hauge, Robert H. (Inventor); Smalley, Richard E. (Inventor)

    2009-01-01

    The present invention is directed toward methods of selectively functionalizing carbon nanotubes of a specific type or range of types, based on their electronic properties, using diazonium chemistry. The present invention is also directed toward methods of separating carbon nanotubes into populations of specific types or range(s) of types via selective functionalization and electrophoresis, and also to the novel compositions generated by such separations.

  6. Carbon nanotubes for coherent spintronics

    DEFF Research Database (Denmark)

    Kuemmeth, Ferdinand; Churchill, H O H; Herring, P K

    2010-01-01

    Carbon nanotubes bridge the molecular and crystalline quantum worlds, and their extraordinary electronic, mechanical and optical properties have attracted enormous attention from a broad scientific community. We review the basic principles of fabricating spin-electronic devices based on individual......, electrically-gated carbon nanotubes, and present experimental efforts to understand their electronic and nuclear spin degrees of freedom, which in the future may enable quantum applications....

  7. Properties of Carbon Nanotubes

    Science.gov (United States)

    Masood, Samina; Bullmore, Daniel; Duran, Michael; Jacobs, Michael

    2012-10-01

    Different synthesizing methods are used to create various nanostructures of carbon; we are mainly interested in single and multi-wall carbon nanotubes, (SWCNTs) and (MWCNTs) respectively. The properties of these tubes are related to their synthetic methods, chirality, and diameter. The extremely sturdy structure of CNTs, with their distinct thermal and electromagnetic properties, suggests a tremendous use of these tubes in electronics and medicines. Here, we analyze various physical properties of SWCNTs with a special emphasis on electromagnetic and chemical properties. By examining their electrical properties, we demonstrate the viability of discrete CNT based components. After considering the advantages of using CNTs over microstructures, we make a case for the advancement and development of nanostructures based electronics. As for current CNT applications, it's hard to overlook their use and functionality in the development of cancer treatment. Whether the tubes are involved in chemotherapeutic drug delivery, molecular imaging and targeting, or photodynamic therapy, we show that the remarkable properties of SWCNTs can be used in advantageous ways by many different industries.

  8. Carbon nanotube computer.

    Science.gov (United States)

    Shulaker, Max M; Hills, Gage; Patil, Nishant; Wei, Hai; Chen, Hong-Yu; Wong, H-S Philip; Mitra, Subhasish

    2013-09-26

    The miniaturization of electronic devices has been the principal driving force behind the semiconductor industry, and has brought about major improvements in computational power and energy efficiency. Although advances with silicon-based electronics continue to be made, alternative technologies are being explored. Digital circuits based on transistors fabricated from carbon nanotubes (CNTs) have the potential to outperform silicon by improving the energy-delay product, a metric of energy efficiency, by more than an order of magnitude. Hence, CNTs are an exciting complement to existing semiconductor technologies. Owing to substantial fundamental imperfections inherent in CNTs, however, only very basic circuit blocks have been demonstrated. Here we show how these imperfections can be overcome, and demonstrate the first computer built entirely using CNT-based transistors. The CNT computer runs an operating system that is capable of multitasking: as a demonstration, we perform counting and integer-sorting simultaneously. In addition, we implement 20 different instructions from the commercial MIPS instruction set to demonstrate the generality of our CNT computer. This experimental demonstration is the most complex carbon-based electronic system yet realized. It is a considerable advance because CNTs are prominent among a variety of emerging technologies that are being considered for the next generation of highly energy-efficient electronic systems.

  9. Carbon Nanotube Purification

    Science.gov (United States)

    Delzeit, Lance D. (Inventor); Delzeit, Clement J. (Inventor)

    2005-01-01

    A method for cleaning or otherwise removing amorphous carbon and other residues that arise in growth of a carbon nanotube (CNT) array. The CNT array is exposed to a plurality of hydroxyls or hydrogen, produced from a selected vapor or liquid source such as H2O or H2O2. and the hydroxyls or hydrogen (neutral or electrically charged) react with the residues to produce partly or fully dissolved or hydrogenated or hydroxylizated products that can be removed or separated from the CNT array. The hydroxyls or hydrogen can be produced by heating the CNT array, residue and selected vapor or liquid source or by application of an electromagnetic excitation signal with a selected frequency or range of frequencies to dissociate the selected vapor or liquid. The excitation frequency can be chirped to cover a selected range of frequencies corresponding to dissociation of the selected vapor or liquid. Sonication may be uscd to supplement dissociation of the H2O and/or H2O2.

  10. Probing Photosensitization by Functionalized Carbon Nanotubes

    Science.gov (United States)

    Carbon nanotubes (CNTs) photosensitize the production of reactive oxygen species that can damage organisms by biomembrane oxidation or mediate CNTs' environmental transformations. The photosensitized nature of derivatized carbon nanotubes from various synthetic methods, and thus ...

  11. Carbon Nanotube Based Molecular Electronics

    Science.gov (United States)

    Srivastava, Deepak; Saini, Subhash; Menon, Madhu

    1998-01-01

    Carbon nanotubes and the nanotube heterojunctions have recently emerged as excellent candidates for nanoscale molecular electronic device components. Experimental measurements on the conductivity, rectifying behavior and conductivity-chirality correlation have also been made. While quasi-one dimensional simple heterojunctions between nanotubes with different electronic behavior can be generated by introduction of a pair of heptagon-pentagon defects in an otherwise all hexagon graphene sheet. Other complex 3- and 4-point junctions may require other mechanisms. Structural stability as well as local electronic density of states of various nanotube junctions are investigated using a generalized tight-binding molecular dynamics (GDBMD) scheme that incorporates non-orthogonality of the orbitals. The junctions investigated include straight and small angle heterojunctions of various chiralities and diameters; as well as more complex 'T' and 'Y' junctions which do not always obey the usual pentagon-heptagon pair rule. The study of local density of states (LDOS) reveal many interesting features, most prominent among them being the defect-induced states in the gap. The proposed three and four pointjunctions are one of the smallest possible tunnel junctions made entirely of carbon atoms. Furthermore the electronic behavior of the nanotube based device components can be taylored by doping with group III-V elements such as B and N, and BN nanotubes as a wide band gap semiconductor has also been realized in experiments. Structural properties of heteroatomic nanotubes comprising C, B and N will be discussed.

  12. Cytotoxicity of carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    ZHU Ying; LI WenXin

    2008-01-01

    With large-scale production and application at large scale, carbon nanotubes (CNTs) may cause ad-verse response to the environment and human health. Thus, study on bio-effects and safety of CNTs has attracted great attention from scientists and governments worldwide. This report briefly summa-rizes the main results from the in vitro toxicity study of CNTs. The emphasis is placed on the descrip-tion of a variety of factors affecting CNTs cytotoxicity, including species of CNTs, impurities contained,lengths of CNTs, aspect ratios, chemical modification, and assaying methods of cytotoxicity. However,experimental information obtained thus far on CNTs' cytotoxicity is lacking in comparability, and some-times there is controversy about it. In order to assess more accurately the potential risks of CNTs to human health, we suggest that care should be taken for issues such as chemical modification and quantitative characterization of CNTa in cytotoxicity assessment. More importantly, studies on physical and chemical mechanisms of CNTs' cytotoxicity should be strengthened; assaying methods and evaluating criteria characterized by nanotoxicology should be gradually established.

  13. Cytotoxicity of carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    With large-scale production and application at large scale, carbon nanotubes (CNTs) may cause ad-verse response to the environment and human health. Thus, study on bio-effects and safety of CNTs has attracted great attention from scientists and governments worldwide. This report briefly summa-rizes the main results from the in vitro toxicity study of CNTs. The emphasis is placed on the descrip-tion of a variety of factors affecting CNTs cytotoxicity, including species of CNTs, impurities contained, lengths of CNTs, aspect ratios, chemical modification, and assaying methods of cytotoxicity. However, experimental information obtained thus far on CNTs’ cytotoxicity is lacking in comparability, and some-times there is controversy about it. In order to assess more accurately the potential risks of CNTs to human health, we suggest that care should be taken for issues such as chemical modification and quantitative characterization of CNTs in cytotoxicity assessment. More importantly, studies on physical and chemical mechanisms of CNTs’ cytotoxicity should be strengthened; assaying methods and evaluating criteria characterized by nanotoxicology should be gradually established.

  14. Hybrid Composite of Polyaniline Containing Carbon Nanotube

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Carbon nanotube-polyaniline hybrid material was synthesized by emulsion polymerization in-situ. The morphology of hybrid material was studied by TEM and X-ray diffraction. The conductivity of nanocomposite increases with the increasing of carbon nanotube content because of the new conductivity passageways formed by carbon nanotubes.

  15. Synthesis and Application of Carbon Nanotubes

    Institute of Scientific and Technical Information of China (English)

    Qun Zeng; Zhenhua Li; Yuhong Zhou

    2006-01-01

    Owing to the unique structure, the superior physical and chemical properties, the super strong mechanical performances, and so on, carbon nanotubes have attracted the attention of researchers all over the world. In this article, the basic properties and the main production processes of carbon nanotubes are introduced in brief, and the progress of applied research for carbon nanotubes is reviewed.

  16. Hydrodynamic properties of carbon nanotubes.

    Science.gov (United States)

    Walther, J H; Werder, T; Jaffe, R L; Koumoutsakos, P

    2004-06-01

    We study water flowing past an array of single walled carbon nanotubes using nonequilibrium molecular dynamics simulations. For carbon nanotubes mounted with a tube spacing of 16.4 x 16.4 nm and diameters of 1.25 and 2.50 nm, respectively, we find drag coefficients in reasonable agreement with the macroscopic, Stokes-Oseen solution. The slip length is -0.11 nm for the 1.25 nm carbon nanotube, and 0.49 for the 2.50 nm tube for a flow speed of 50 m/s, respectively, and 0.28 nm for the 2.50 nm tube at 200 m/s. A slanted flow configuration with a stream- and spanwise velocity component of 100 ms(-1) recovers the two-dimensional results, but exhibits a significant 88 nm slip along the axis of the tube. These results indicate that slip depends on the particular flow configuration.

  17. Adsorption on the carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    DING Yi; YANG Xiao-bao; NI Jun

    2006-01-01

    Adsorption on single walled carbon nanotubes (SWCNTs) is a subject of growing experimental and theoretical interest.The possible adsorbed patterns of atoms and molecules on the single-walled carbon nanotubes vary with the diameters and chirality of the tubes due to the confinement.The curvature of the carbon nanotube surface enlarges the distance of the adsorbate atoms and thus enhances the stability of high coverage structures of adsorbate.There exist two novel high-coverage stable structures of potassium adsorbed on SWCNTs,which are not stable on graphite.The electronic properties of SWCNTs can be modified by adsorbate atoms and metal-semiconductor and semiconductor-semi-conductor transitions can be achieved by the doping of alkali atoms.

  18. Carbon nanotube-polymer composite actuators

    Science.gov (United States)

    Gennett, Thomas; Raffaelle, Ryne P.; Landi, Brian J.; Heben, Michael J.

    2008-04-22

    The present invention discloses a carbon nanotube (SWNT)-polymer composite actuator and method to make such actuator. A series of uniform composites was prepared by dispersing purified single wall nanotubes with varying weight percents into a polymer matrix, followed by solution casting. The resulting nanotube-polymer composite was then successfully used to form a nanotube polymer actuator.

  19. Modified carbon nanotubes and methods of forming carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Heintz, Amy M.; Risser, Steven; Elhard, Joel D.; Moore, Bryon P.; Liu, Tao; Vijayendran, Bhima R.

    2016-06-14

    In this invention, processes which can be used to achieve stable doped carbon nanotubes are disclosed. Preferred CNT structures and morphologies for achieving maximum doping effects are also described. Dopant formulations and methods for achieving doping of a broad distribution of tube types are also described.

  20. Effects of Fin Shape on Condensation Heat Transfer and Pressure Drop inside Herringbone Micro Fin Tubes

    Science.gov (United States)

    Miyara, Akio; Otsubo, Yusuke; Ohtsuka, Satoshi

    Experiments of in-tube condensation of R410A have been carried out for as mooth tube, a h elical micro fin tube and five types of herringbone micro fin tubes. In the herringbone micro fin tube, the micro fins work to remove liquid at fin-diverging parts and collect liquid at fin-converging parts. In the high mass velocity region, heat transfer coefficient of all the herringbone tubes is about 2-4 times higher than that of the helical micro fin tube. In the low mass velocity region, however, the heat transfer coefficients of the herringbone micro fin tubes are equal to or smaller than those of the helical micro fin tube. Up to the fin height of 0.18 mm, the heat transfer coefficient is higher for higher fin, whereas that of ah igher fin tube is saturated. The pressure drop increases with increasing fin height. The helix angle strongly affects the heat transfer and pressure drop. Higher helix angle causes higher heat transfer coefficient and higher pressure drop. In the case of the herringbone tube which has shorter fin and/or smaller helix angle, pressure drops are equal to or lower than that of the helical micro fin tube, whereas those of other tubes are higher.

  1. Characteristics and formation mechanism for stainless steel fiber with periodic micro-fins

    Science.gov (United States)

    Tang, Tao; Wan, Zhenping; Lu, Longsheng; Tang, Yong

    2016-05-01

    Metal fibers have been widely used in many industrial applications due to their unique advantages. In certain applications, such as catalyst supports or orthopedic implants, a rough surface or tiny outshoots on the surface of metal fibers to increase surface area are needed. However, it has not been concerned about the surface morphologies of metal fiber in the current research of metal fiber manufacturing. In this paper, a special multi-tooth tool composed of a row of triangular tiny teeth is designed. The entire cutting layer of multi-tooth tool bifurcates into several thin cutting layers due to tiny teeth involved in cutting. As a result, several stainless steel fibers with periodic micro-fins are produced simultaneously. Morphology of periodic micro-fins is found to be diverse and can be classified into three categories: unilateral plane, unilateral tapering and bilateral. There are two forming mechanisms for the micro-fins. One is that periodic burrs remained on the free side of cutting layer of a tiny tooth create micro-fins of stainless steel fiber produced by the next neighboring tiny tooth; the other is that the connections between two fibers stuck together come to be micro-fins if the two fibers are finally detached. Influence of cutting conditions on formation of micro-fins is investigated. Experimental results show that cutting depth has no significant effect on micro-fin formation, high cutting speed is conducive to micro-fin formation, and feed should be between 0.12 mm/r and 0.2 mm/r to reliably obtain stainless steel fiber with micro-fins. This research presents a new pattern of stainless steel fiber characterized by periodic micro-fins formed on the edge of fiber and its manufacturing method.

  2. Quantum transport in carbon nanotubes

    NARCIS (Netherlands)

    Laird, E.A.; Kuemmeth, F.; Steele, G.A.; Grove-Rasmussen, K.; Nygard, J.; Flensberg, K.; Kouwenhoven, L.P.

    2015-01-01

    Carbon nanotubes are a versatile material in which many aspects of condensed matter physics come together. Recent discoveries have uncovered new phenomena that completely change our understanding of transport in these devices, especially the role of the spin and valley degrees of freedom. This revie

  3. Peel test of spinnable carbon nanotube webs

    Science.gov (United States)

    Khandoker, Noman; Hawkins, Stephen C.; Ibrahim, Raafat; Huynh, Chi P.

    2014-06-01

    This paper presents results of peel tests with spinnable carbon nanotube webs. Peel tests were performed to study the effect of orientation angles on interface energies between nanotubes. In absence of any binding agent the interface energy represents the Van Der Waals energies between the interacting nanotubes. Therefore, the effect of the orientations on Van Der Waals energies between carbon nanotubes is obtained through the peel test. It is shown that the energy for crossed nanotubes at 90° angle is lower than the energy for parallel nanotubes at 0° angle. This experimental observation was validated by hypothetical theoretical calculations.

  4. From carbon nanotubes to carbon atomic chains

    Science.gov (United States)

    Casillas García, Gilberto; Zhang, Weijia; José-Yacamán, Miguel

    2010-10-01

    Carbyne is a linear allotrope of carbon. It is formed by a linear arrangement of carbon atoms with sp-hybridization. We present a reliable and reproducible experiment to obtain these carbon atomic chains using few-layer-graphene (FLG) sheets and a HRTEM. First the FLG sheets were synthesized from worm-like exfoliated graphite and then drop-casted on a lacey-carbon copper grid. Once in the TEM, two holes are opened near each other in a FLG sheet by focusing the electron beam into a small spot. Due to the radiation, the carbon atoms rearrange themselves between the two holes and form carbon fibers. The beam is concentrated on the carbon fibers in order excite the atoms and induce a tension until multi wall carbon nanotube (MWCNT) is formed. As the radiation continues the MWCNT breaks down until there is only a single wall carbon nanotube (SWCNT). Then, when the SWCNT breaks, an atomic carbon chain is formed, lasts for several seconds under the radiation and finally breaks. This demonstrates the stability of this carbon structure.

  5. Attachment of Gold Nanoparticles to Carbon Nanotubes

    Institute of Scientific and Technical Information of China (English)

    Xi Cheng MA; Ning LUN; Shu Lin WEN

    2005-01-01

    Carbon nanotubes were initially chemically modified with an H2SO4-HNO3 treatment,and subsequently activated with Pd-Sn catalytic nuclei via a one-step activation approach. These activated nanotubes were used as precursors for obtaining gold nanoparticles-attached nanotubes via simple electroless plating. This approach provides an efficient method for attachment of metal nanostructures to carbon nanotubes. Such novel hybrid nanostructures are attractive for many applications.

  6. Pulsed laser deposition of carbon nanotube and polystyrene-carbon nanotube composite thin films

    Science.gov (United States)

    Stramel, A. A.; Gupta, M. C.; Lee, H. R.; Yu, J.; Edwards, W. C.

    2010-12-01

    In this work, we report on the fabrication of carbon nanotube thin films via pulsed laser deposition using a pulsed, diode pumped, Tm:Ho:LuLF laser with 2 μm wavelength. The thin films were deposited on silicon substrates using pure carbon nanotube targets and polystyrene-carbon nanotube composite targets. Raman spectra, scanning electron micrographs, and transmission electron micrographs show that carbon nanotubes are present in the deposited thin films, and that the pulsed laser deposition process causes minimal degradation to the quality of the nanotubes when using pure carbon nanotube targets.

  7. Bloch oscillations in carbon nanotubes.

    Science.gov (United States)

    Jódar, Esther; Pérez-Garrido, Antonio; Rojas, Fernando

    2009-05-27

    Bloch oscillations arise when electrons are in a one-dimensional linear chain of atoms under a constant electric field. In this paper we show numerically that electrons in different types of carbon nanotubes show oscillations with a Bloch frequency proportional to the constant electric field applied along the nanotube axis. We show these oscillations, calculating the quadratic displacement as a function of the electric field. Because of the double periodicity of the nanotubes' geometry (the lattice constant and the lines of atoms) two frequencies appear, one twice the value of the other. These frequencies coincide perfectly with those predicted for a linear chain of atoms, taking into account the periodicity considered in each case.

  8. Bloch oscillations in carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Jodar, Esther; Perez-Garrido, Antonio [Departamento Fisica Aplicada, Antiguo Hospital de Marina Campus Muralla del Mar, UPCT, Cartagena 30202 Murcia (Spain); Rojas, Fernando [Centro de Nanociencias y Nanotecnologia-UNAM, Apartado Postal 356, Ensenada, Baja California 22800 (Mexico)], E-mail: ejodar@upct.es

    2009-05-27

    Bloch oscillations arise when electrons are in a one-dimensional linear chain of atoms under a constant electric field. In this paper we show numerically that electrons in different types of carbon nanotubes show oscillations with a Bloch frequency proportional to the constant electric field applied along the nanotube axis. We show these oscillations, calculating the quadratic displacement as a function of the electric field. Because of the double periodicity of the nanotubes' geometry (the lattice constant and the lines of atoms) two frequencies appear, one twice the value of the other. These frequencies coincide perfectly with those predicted for a linear chain of atoms, taking into account the periodicity considered in each case. (fast track communication)

  9. Characteristics of a micro-fin evaporator: Theoretical analysis and experimental verification

    Directory of Open Access Journals (Sweden)

    Zheng Hui-Fan

    2013-01-01

    Full Text Available A theoretical analysis and experimental verification on the characteristics of a micro-fin evaporator using R290 and R717 as refrigerants were carried out. The heat capacity and heat transfer coefficient of the micro-fin evaporator were investigated under different water mass flow rate, different refrigerant mass flow rate, and different inner tube diameter of micro-fin evaporator. The simulation results of the heat transfer coefficient are fairly in good agreement with the experimental data. The results show that heat capacity and the heat transfer coefficient of the micro-fin evaporator increase with increasing logarithmic mean temperature difference, the water mass flow rate and the refrigerant mass flow rate. Heat capacity of the micro-fin evaporator for diameter 9.52 mm is higher than that of diameter 7.00 mm with using R290 as refrigerant. Heat capacity of the micro-fin evaporator with using R717 as refrigerant is higher than that of R290 as refrigerant. The results of this study can provide useful guidelines for optimal design and operation of micro-fin evaporator in its present or future applications.

  10. Pressure-Induced Interlinking of Carbon Nanotubes

    OpenAIRE

    Yildirim, T.; Gulseren, O.; Kilic, C.; Ciraci, S.

    2000-01-01

    We predict new forms of carbon consisting of one and two dimensional networks of interlinked single wall carbon nanotubes, some of which are energetically more stable than van der Waals packing of the nanotubes on a hexagonal lattice. These interlinked nanotubes are further transformed with higher applied external pressures to more dense and complicated stable structures, in which curvature-induced carbon sp$^{3}$ re-hybridizations are formed. We also discuss the energetics of the bond format...

  11. Different Technical Applications of Carbon Nanotubes

    OpenAIRE

    Abdalla, S; Al-Marzouki, F.; Ahmed A. Al-Ghamdi; Abdel-Daiem, A.

    2015-01-01

    Carbon nanotubes have been of great interest because of their simplicity and ease of synthesis. The novel properties of nanostructured carbon nanotubes such as high surface area, good stiffness, and resilience have been explored in many engineering applications. Research on carbon nanotubes have shown the application in the field of energy storage, hydrogen storage, electrochemical supercapacitor, field-emitting devices, transistors, nanoprobes and sensors, composite material, templates, etc....

  12. Faster and Smaller with Carbon Nanotubes?

    OpenAIRE

    Seidel, Robert V.; Graham, Andrew P.; Duesberg, Georg S.; Liebau, Maik; Unger, Eugen; Kreupl, Franz; Hoenlein, Wolfgang

    2004-01-01

    Carbon Nanotubes seem to be one of the most promising candidates for nanoelectronic devices beyond presumable scaling limits of silicon and compound semiconductors and independent from lithographic limitations. Discovered only about a decade ago, there has been a tremendous advance in the field of carbon nanotubes. Their exciting properties, especially with respect to electronic applications, and their fabrication methods will be discussed. A variety of Carbon Nanotube...

  13. Carbon Nanotubes and Related Structures

    Directory of Open Access Journals (Sweden)

    Kingsuk Mukhopadhyay

    2008-07-01

    Full Text Available Carbon nanotubes have attracted the fancy of many scientists world wide. The small dimensions,strength, and the remarkable physical properties of these structures make them a unique material with a whole range of promising applications. In this review, the structural aspects, the advantages and disadvantages of different for their procedures synthesis, the qualitative and quantitative estimation of carbon nanotubes by different analytical techniques, the present status on their applications as well as the current challenges faced in the application field, national, in particular DRDO, DMSRDE status, and interest in this field, have been discussed.Defence Science Journal, 2008, 58(4, pp.437-450, DOI:http://dx.doi.org/10.14429/dsj.58.1666

  14. Ballistic Fracturing of Carbon Nanotubes.

    Science.gov (United States)

    Ozden, Sehmus; Machado, Leonardo D; Tiwary, ChandraSekhar; Autreto, Pedro A S; Vajtai, Robert; Barrera, Enrique V; Galvao, Douglas S; Ajayan, Pulickel M

    2016-09-21

    Advanced materials with multifunctional capabilities and high resistance to hypervelocity impact are of great interest to the designers of aerospace structures. Carbon nanotubes (CNTs) with their lightweight and high strength properties are alternative to metals and/or metallic alloys conventionally used in aerospace applications. Here we report a detailed study on the ballistic fracturing of CNTs for different velocity ranges. Our results show that the highly energetic impacts cause bond breakage and carbon atom rehybridizations, and sometimes extensive structural reconstructions were also observed. Experimental observations show the formation of nanoribbons, nanodiamonds, and covalently interconnected nanostructures, depending on impact conditions. Fully atomistic reactive molecular dynamics simulations were also carried out in order to gain further insights into the mechanism behind the transformation of CNTs. The simulations show that the velocity and relative orientation of the multiple colliding nanotubes are critical to determine the impact outcome.

  15. Carbon Nanotubes: Molecular Electronic Components

    Science.gov (United States)

    Srivastava, Deepak; Saini, Subhash; Menon, Madhu

    1997-01-01

    The carbon Nanotube junctions have recently emerged as excellent candidates for use as the building blocks in the formation of nanoscale molecular electronic networks. While the simple joint of two dissimilar tubes can be generated by the introduction of a pair of heptagon-pentagon defects in an otherwise perfect hexagonal graphene sheet, more complex joints require other mechanisms. In this work we explore structural characteristics of complex 3-point junctions of carbon nanotubes using a generalized tight-binding molecular-dynamics scheme. The study of pi-electron local densities of states (LDOS) of these junctions reveal many interesting features, most prominent among them being the defect-induced states in the gap.

  16. Torsional Carbon Nanotube Artificial Muscles

    Science.gov (United States)

    Foroughi, Javad; Spinks, Geoffrey M.; Wallace, Gordon G.; Oh, Jiyoung; Kozlov, Mikhail E.; Fang, Shaoli; Mirfakhrai, Tissaphern; Madden, John D. W.; Shin, Min Kyoon; Kim, Seon Jeong; Baughman, Ray H.

    2011-10-01

    Rotary motors of conventional design can be rather complex and are therefore difficult to miniaturize; previous carbon nanotube artificial muscles provide contraction and bending, but not rotation. We show that an electrolyte-filled twist-spun carbon nanotube yarn, much thinner than a human hair, functions as a torsional artificial muscle in a simple three-electrode electrochemical system, providing a reversible 15,000° rotation and 590 revolutions per minute. A hydrostatic actuation mechanism, as seen in muscular hydrostats in nature, explains the simultaneous occurrence of lengthwise contraction and torsional rotation during the yarn volume increase caused by electrochemical double-layer charge injection. The use of a torsional yarn muscle as a mixer for a fluidic chip is demonstrated.

  17. Carbon nanotubes in tissue engineering.

    Science.gov (United States)

    Bosi, Susanna; Ballerini, Laura; Prato, Maurizio

    2014-01-01

    As a result of their peculiar features, carbon nanotubes (CNTs) are emerging in many areas of nanotechnology applications. CNT-based technology has been increasingly proposed for biomedical applications, to develop biomolecule nanocarriers, bionanosensors and smart material for tissue engineering purposes. In the following chapter this latter application will be explored, describing why CNTs can be considered an ideal material able to support and boost the growth and the proliferation of many kinds of tissues.

  18. A Thermal Model for Carbon Nanotube Interconnects

    Science.gov (United States)

    Mohsin, Kaji Muhammad; Srivastava, Ashok; Sharma, Ashwani K.; Mayberry, Clay

    2013-01-01

    In this work, we have studied Joule heating in carbon nanotube based very large scale integration (VLSI) interconnects and incorporated Joule heating influenced scattering in our previously developed current transport model. The theoretical model explains breakdown in carbon nanotube resistance which limits the current density. We have also studied scattering parameters of carbon nanotube (CNT) interconnects and compared with the earlier work. For 1 µm length single-wall carbon nanotube, 3 dB frequency in S12 parameter reduces to ~120 GHz from 1 THz considering Joule heating. It has been found that bias voltage has little effect on scattering parameters, while length has very strong effect on scattering parameters.

  19. OPPORTUNITIES OF BIOMEDICAL USE OF CARBON NANOTUBES

    Directory of Open Access Journals (Sweden)

    I. V. Mitrofanova

    2014-01-01

    Full Text Available Nanomaterials  –  materials,  whouse  structure  elements  has  proportions  doesn’t  exceed  100  nm.  In superdispersed state matter acquire new properties. In the last decade, carbon nanotubes become the most popular nanomaterials, that cause attention of representatives of various scientific field. The сarbon nanotubes offer new opportunities for biological and medical applications: imaging at the molecular, cellular and tissue levels, biosensors and electrodes based on carbon nanotubes, target delivery of various substances, radiation and photothermal therapy. The most promising of carbon nanotubes in the context of biomedical applications is their ability to penetrate the various tissues of the body and carry large doses of agents, providing diagnostic and therapeutic effects. Functionalized nanotubes are biodegradable. Other current direction of using carbon nanotubes in medicine and biology is to visualize objects on the molecular, cellular and tissue level. Associated with carbon nanotubes contrasting substances improve the visualization of cells and tissues, which can detected new patterns of development of the pathological process. Due to the vagueness of the question of biocompatibility and cytotoxicity of carbon nanotubes possibility of their practical application is hampered. Before the introduction of carbon nanotubes into practical health care is necessary to provide all the possible consequences of using nanotubes. High rates of properties and development of new nanostructures based on carbon nanotubes in the near future will lead to new advances related to the application and development of new parameters that will determine their properties and effects. In these review attention is paid to the structure, physico-chemical properties of nanotubes, their functionalization, pharmacokinetics and pharmacodynamics and all aspects of using of carbon nanotubes.

  20. Liquid surface model for carbon nanotube energetics

    DEFF Research Database (Denmark)

    Solov'yov, Ilia; Mathew, Maneesh; Solov'yov, Andrey V.;

    2008-01-01

    an important insight in the energetics and stability of nanotubes of different chirality and might be important for the understanding of nanotube growth process. For the computations we use empirical Brenner and Tersoff potentials and discuss their applicability to the study of carbon nanotubes. From......In the present paper we developed a model for calculating the energy of single-wall carbon nanotubes of arbitrary chirality. This model, which we call as the liquid surface model, predicts the energy of a nanotube with relative error less than 1% once its chirality and the total number of atoms...... are known. The parameters of the liquid surface model and its potential applications are discussed. The model has been suggested for open end and capped nanotubes. The influence of the catalytic nanoparticle, atop which nanotubes grow, on the nanotube stability is also discussed. The suggested model gives...

  1. LDRD final report on carbon nanotube composites

    Energy Technology Data Exchange (ETDEWEB)

    Cahill, P.A.; Rand, P.B.

    1997-04-01

    Carbon nanotubes and their composites were examined using computational and experimental techniques in order to modify the mechanical and electrical properties of resins. Single walled nanotubes were the focus of the first year effort; however, sufficient quantities of high purity single walled nanotubes could not be obtained for mechanical property investigations. The unusually high electrical conductivity of composites loaded with <1% of multiwalled nanotubes is useful, and is the focus of continuing, externally funded, research.

  2. Engineering carbon nanotubes and nanotube circuits using electrical breakdown.

    Science.gov (United States)

    Collins, P G; Arnold, M S; Avouris, P

    2001-04-27

    Carbon nanotubes display either metallic or semiconducting properties. Both large, multiwalled nanotubes (MWNTs), with many concentric carbon shells, and bundles or "ropes" of aligned single-walled nanotubes (SWNTs), are complex composite conductors that incorporate many weakly coupled nanotubes that each have a different electronic structure. Here we demonstrate a simple and reliable method for selectively removing single carbon shells from MWNTs and SWNT ropes to tailor the properties of these composite nanotubes. We can remove shells of MWNTs stepwise and individually characterize the different shells. By choosing among the shells, we can convert a MWNT into either a metallic or a semiconducting conductor, as well as directly address the issue of multiple-shell transport. With SWNT ropes, similar selectivity allows us to generate entire arrays of nanoscale field-effect transistors based solely on the fraction of semiconducting SWNTs.

  3. Plasticity and Kinky Chemistry of Carbon Nanotubes

    Science.gov (United States)

    Srivastava, Deepak; Dzegilenko, Fedor

    2000-01-01

    Since their discovery in 1991, carbon nanotubes have been the subject of intense research interest based on early predictions of their unique mechanical, electronic, and chemical properties. Materials with the predicted unique properties of carbon nanotubes are of great interest for use in future generations of aerospace vehicles. For their structural properties, carbon nanotubes could be used as reinforcing fibers in ultralight multifunctional composites. For their electronic properties, carbon nanotubes offer the potential of very high-speed, low-power computing elements, high-density data storage, and unique sensors. In a continuing effort to model and predict the properties of carbon nanotubes, Ames accomplished three significant results during FY99. First, accurate values of the nanomechanics and plasticity of carbon nanotubes based on quantum molecular dynamics simulations were computed. Second, the concept of mechanical deformation catalyzed-kinky-chemistry as a means to control local chemistry of nanotubes was discovered. Third, the ease of nano-indentation of silicon surfaces with carbon nanotubes was established. The elastic response and plastic failure mechanisms of single-wall nanotubes were investigated by means of quantum molecular dynamics simulations.

  4. Dielectrophoretic assembly of carbon nanotube devices

    DEFF Research Database (Denmark)

    Dimaki, Maria

    The purpose of this project has been to assemble single-walled carbon nanotubes on electrodes at the tip of a biocompatible cantilever and use these for chemical species sensing in air and liquid, for example in order to measure the local activity from ion channels in the cell membrane....... The electrical resistance of carbon nanotubes has been shown to be extremely sensitive to gas molecules. Dielectrophoresis is a method capable of quickly attracting nanotubes on microelectrodes by using an electric field, thus enabling nanotube integration in microsystems. Dielectrophoresis offers also...... the potential of distinguishing between nanotubes of different electrical properties, which is very important for the optimisation of the properties of the carbon nanotube sensors. Various cantilever and planar structures were designed, fabricated and tested both with multi-walled and single-walled carbon...

  5. Sorting carbon nanotubes for electronics.

    Science.gov (United States)

    Martel, Richard

    2008-11-25

    Because of their unique structure and composition, single-wall carbon nanotubes (SWNTs) are at the interface between molecules and crystalline solids. They also present properties that are ideal for making lightweight, inexpensive, and flexible electronics. The raw material is composed of a heterogeneous mixture of SWNTs that differ in helicity and diameter and, therefore, requires purification and separation. In a series of groundbreaking experiments, a robust process serving this purpose was developed based on SWNTs encapsulated in surfactants and water. Ultracentrifugation in a density gradient combined with surfactant mixtures provided buoyant density differences, enabling enrichment for both diameter and electronic properties. A new paper in this issue explores further the process through the hydrodynamic properties of SWNT-surfactant complexes. The study reveals that we have just begun to uncover the dynamics and properties of nanotube-surfactant interactions and highlights the potential that could be gained from a better understanding of their chemistry. The time scale of integration of carbon nanotubes into electronics applications remains unclear, but the recent developments in sorting out SWNTs paves the way for improving on the properties of network-based SWNTs.

  6. Study of Carbon Nanotube-Substrate Interaction

    Directory of Open Access Journals (Sweden)

    Jaqueline S. Soares

    2012-01-01

    Full Text Available Environmental effects are very important in nanoscience and nanotechnology. This work reviews the importance of the substrate in single-wall carbon nanotube properties. Contact with a substrate can modify the nanotube properties, and such interactions have been broadly studied as either a negative aspect or a solution for developing carbon nanotube-based nanotechnologies. This paper discusses both theoretical and experimental studies where the interaction between the carbon nanotubes and the substrate affects the structural, electronic, and vibrational properties of the tubes.

  7. CARBON NANOTUBES: PROPERTIES AND APPLICATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, John, E.

    2009-07-24

    Carbon nanotubes were discovered in 1991 as a minority byproduct of fullerene synthesis. Remarkable progress has been made in the ensuing years, including the discovery of two basic types of nanotubes (single-wall and multi-wall), great strides in synthesis and purification, elucidation of many fundamental physical properties, and important steps towards practical applications. Both the underlying science and technological potential of SWNT can profitably be studied at the scale of individual tubes and on macroscopic assemblies such as fibers. Experiments on single tubes directly reveal many of the predicted quantum confinement and mechanical properties. Semiconductor nanowires have many features in common with nanotubes, and many of the same fundamental and practical issues are in play – quantum confinement and its effect on properties; possible device structures and circuit architectures; thermal management; optimal synthesis, defect morphology and control, etc. In 2000 we began a small effort in this direction, conducted entirely by undergraduates with minimal consumables support from this grant. With DOE-BES approval, this grew into a project in parallel with the carbon nanotube work, in which we studied of inorganic semiconductor nanowire growth, characterization and novel strategies for electronic and electromechanical device fabrication. From the beginnings of research on carbon nanotubes, one of the major applications envisioned was hydrogen storage for fuel-cell powered cars and trucks. Subsequent theoretical models gave mixed results, the most pessimistic indicating that the fundamental H2-SWNT interaction was similar to flat graphite (physisorption) with only modest binding energies implying cryogenic operation at best. New material families with encouraging measured properties have emerged, and materials modeling has gained enormously in predictive power, sophistication, and the ability to treat a realistically representative number of atoms. One of

  8. Amorphous Carbon-Boron Nitride Nanotube Hybrids

    Science.gov (United States)

    Kim, Jae Woo (Inventor); Siochi, Emilie J. (Inventor); Wise, Kristopher E. (Inventor); Lin, Yi (Inventor); Connell, John (Inventor)

    2016-01-01

    A method for joining or repairing boron nitride nanotubes (BNNTs). In joining BNNTs, the nanotube structure is modified with amorphous carbon deposited by controlled electron beam irradiation to form well bonded hybrid a-C/BNNT structures. In repairing BNNTs, the damaged site of the nanotube structure is modified with amorphous carbon deposited by controlled electron beam irradiation to form well bonded hybrid a-C/BNNT structures at the damage site.

  9. A Tunable Carbon Nanotube Oscillator

    Science.gov (United States)

    Sazonova, Vera

    2005-03-01

    Nanoelectromechanical systems (NEMS) hold promise for a number of scientific and technological applications. Carbon nanotubes (NT) are perhaps the ultimate material for realizing a NEMS device as they are the stiffest material known, have low density, ultrasmall cross sections and can be defect-free. Equally important, a nanotube can act as a transistor and thus is able to sense its own motion. Here, we report the electrical actuation and detection of the guitar-string oscillation modes of doubly-clamped NT oscillators. We observed resonance frequencies in the 5MHz to 150MHz range with quality factors in the 50 to 100 range. We showed that the resonance frequencies can be widely tuned by a gate voltage. We also report on the temperature dependence of the quality factor and present a discussion of possible loss mechanisms.

  10. Mechanics of filled carbon nanotubes

    KAUST Repository

    Monteiro, A.O.

    2014-04-01

    The benefits of filling carbon nanotubes (CNTs) with assorted molecular and crystalline substances have been investigated for the past two decades. Amongst the study of new structural phases, defects, chemical reactions and varied types of host-guest interactions, there is one fundamental characterisation aspect of these systems that continues to be overlooked: the mechanical behaviour of filled CNTs. In contrast to their empty counterparts, the mechanics of filled CNTs is a subject where reports appear far and apart, this despite being key to the application of these materials in technological devices. In the following paragraphs, we review the work that has been carried out up to the present on the mechanics of filled CNTs. The studies discussed range from experimental resonant frequency essays performed within electron microscopes to modelling, via molecular dynamics, of three-point bending of nanotubes filled with gases. (C) 2014 Elsevier B.V. All rights reserved.

  11. Hydrogen Storage in Carbon Nanotubes

    Science.gov (United States)

    Gilbert, Joseph; Gilbert, Matthew; Naab, Fabian; Savage, Lauren; Holland, Wayne; Duggan, Jerome; McDaniel, Floyd

    2004-10-01

    Hydrogen as a fuel source is an attractive, relatively clean alternative to fossil fuels. However, a major limitation in its use for the application of automobiles has been the requirement for an efficient hydrogen storage medium. Current hydrogen storage systems are: physical storage in high pressure tanks, metal hydride, and gas-on-solid absorption. However, these methods do not fulfill the Department of Energy's targeted requirements for a usable hydrogen storage capacity of 6.5 wt.%, operation near ambient temperature and pressure, quick extraction and refueling, reliability and reusability.Reports showing high capacity hydrogen storage in single-walled carbon nanotubes originally prompted great excitement in the field, but further research has shown conflicting results. Results for carbon nanostructures have ranged from less than 1 wt.% to 70 wt.%. The wide range of adsorption found in previous experiments results from the difficulty in measuring hydrogen in objects just nanometers in size. Most previous experiments relied on weight analysis and residual gas analysis to determine the amount of hydrogen being adsorbed by the CNTs. These differing results encouraged us to perform our own analysis on single-walled (SWNTs), double-walled (DWNTs), and multi-walled carbon nanotubes (MWNTs), as well as carbon fiber. We chose to utilize direct measurement of hydrogen in the materials using elastic recoil detection analysis (ERDA). This work was supported by the National Science Foundation's Research Experience for Undergraduates and the University of North Texas.

  12. Glucose oxidase immobilization onto carbon nanotube networking

    CERN Document Server

    Karachevtsev, V A; Zarudnev, E S; Karachevtsev, M V; Leontiev, V S; Linnik, A S; Lytvyn, O S; Plokhotnichenko, A M; Stepanian, S G

    2012-01-01

    When elaborating the biosensor based on single-walled carbon nanotubes (SWNTs), it is necessary to solve such an important problem as the immobilization of a target biomolecule on the nanotube surface. In this work, the enzyme (glucose oxidase (GOX)) was immobilized on the surface of a nanotube network, which was created by the deposition of nanotubes from their solution in 1,2-dichlorobenzene by the spray method. 1-Pyrenebutanoic acid succinimide ester (PSE) was used to form the molecular interface, the bifunctional molecule of which provides the covalent binding with the enzyme shell, and its other part (pyrene) is adsorbed onto the nanotube surface. First, the usage of such a molecular interface leaves out the direct adsorption of the enzyme (in this case, its activity decreases) onto the nanotube surface, and, second, it ensures the enzyme localization near the nanotube. The comparison of the resonance Raman (RR) spectrum of pristine nanotubes with their spectrum in the PSE environment evidences the creat...

  13. Polymer Self-assembly on Carbon Nanotubes

    Science.gov (United States)

    Giulianini, Michele; Motta, Nunzio

    This chapter analyses the poly(3-hexylthiophene) self-assembly on carbon nanotubes and the interaction between the two materials forming a new hybrid nanostructure. The chapter starts with a review of the several studies investigating polymers and biomolecules self-assembled on nanotubes. Then conducting polymers and polythiophenes are briefly introduced. Accordingly, carbon nanotube structure and properties are reported in Sect. 3. The experimental section starts with the bulk characterisation of polymer thin films with the inclusion of uniformly distributed carbon nanotubes. By using volume film analysis techniques (AFM, TEM, UV-Vis and Raman), we show how the polymer's higher degree of order is a direct consequence of interaction with carbon nanotubes. Nevertheless, it is through the use of nanoscale analysis and molecular dynamic simulations that the self-assembly of the polymer on the nanotube surface can be clearly evidenced and characterised. In Sect. 6, the effect of the carbon templating structure on the P3HT organisation on the surface is investigated, showing the chirality-driven polymer assembly on the carbon nanotube surface. The interaction between P3HT and CNTs brings also to charge transfer, with the modification of physical properties for both species. In particular, the alteration of the polymer electronic properties and the modification of the nanotube mechanical structure are a direct consequence of the P3HT π-π stacking on the nanotube surface. Finally, some considerations based on molecular dynamics studies are reported in order to confirm and support the experimental results discussed.

  14. Suspended carbon nanotubes coupled to superconducting circuits

    NARCIS (Netherlands)

    Schneider, B.H.

    2014-01-01

    Carbon nanotubes are unique candidates to study quantum mechanical properties of a nanomechanical resonator. However to access this quantum regime, present detectors are not yet sensitive enough. In this thesis we couple a carbon nanotube CNT mechanical resonator to a superconducting circuit which i

  15. Carbon Nanotubes – Interactions with Biological Systems

    OpenAIRE

    Reis, Joana; Capela-Silva, Fernando; Potes, José; Fonseca, Alexandra; Oliveira, Mónica; Kanagaraj, Subramani; Marques, António Torres

    2011-01-01

    his book chapter discusses the prospective biomedical applications of carbon nanotubes based materials, the impact of carbon nanotubes properties in the interaction with biological systems. Protein adsorption, impact on cell viability and cytokine production are explored. Potential respiratory and dermal toxicity are reviewed, as the difficulties on studying the biological response. In face of recent studies, special attention is drawn upon promising orthopaedic use.

  16. Multiscale Simulations of Carbon Nanotubes and Liquids

    Science.gov (United States)

    Koumoutsakos, Petros

    2005-11-01

    We present molecular dynamics and hybrid continuum/atomistic simulations of carbon nanotubes in liquid environments with an emphasis on aqueous solutions. We emphasize computational issues such as interaction potentials and coupling techniques and their influence on the simulated physics. We present results from simulations of water flows inside and outside doped and pure carbon nanotubes and discuss their implications for experimental studies.

  17. Development of supercapacitors based on carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Block-type electrodes made of carbon nanotubes were fabricated by different processes. The volumetric specific capacitance based on such electrodes reached 107 F/cm3, which proves carbon nanotubes to be ideal candidate materials for supercapacitors. The composite electrodes consisting of carbon nanotubes and RuO2.xH2O were developed by the deposition of RuO2 on the surface of carbon nanotubes. Supercapacitors based on the composite electrodes show much higher specific capacitance than those based on pure carbon nanotube ones. A specific capacitance of 600 F/g can be achieved when the weight percent of RuO2.xH2O in the composite electrodes reaches 75%. In addition, supercapacitors based on the composite electrodes show both high energy density and high power density characteristics.

  18. Development of supercapacitors based on carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    马仁志; 魏秉庆; 徐才录; 梁吉; 吴德海

    2000-01-01

    Block-type electrodes made of carbon nanotubes were fabricated by different processes. The volumetric specific capacitance based on such electrodes reached 107 F/cm3, which proves carbon nanotubes to be ideal candidate materials for supercapacitors. The composite electrodes consisting of carbon nanotubes and RuO2 ·xH2O were developed by the deposition of RuO2 on the surface of carbon nanotubes. Supercapacitors based on the composite electrodes show much higher specific capacitance than those based on pure carbon nanotube ones. A specific capacitance of 600 F/g can be achieved when the weight percent of RuO2· xH2O in the composite electrodes reaches 75% . In addition , supercapacitors based on the composite electrodes show both high energy density and high power density characteristics.

  19. Epitaxial Approaches to Carbon Nanotube Organization

    Science.gov (United States)

    Ismach, Ariel

    Carbon nanotubes have unique electronic, mechanical, optical and thermal properties, which make them ideal candidates as building blocks in nano-electronic and electromechanical systems. However, their organization into well-defined geometries and arrays on surfaces remains a critical challenge for their integration into functional nanosystems. In my PhD, we developed a new approach for the organization of carbon nanotubes directed by crystal surfaces. The principle relies on the guided growth of single-wall carbon nanotubes (SWNTs) by atomic features presented on anisotropic substrates. We identified three different modes of surface-directed growth (or 'nanotube epitaxy'), in which the growth of carbon nanotubes is directed by crystal substrates: We first observed the nanotube unidirectional growth along atomic steps ('ledge-directed epitaxy') and nanofacets ('graphoepitaxy') on the surface of miscut C-plane sapphire and quartz. The orientation along crystallographic directions ('lattice-directed epitaxy') was subsequently observed by other groups on different crystals. We have proposed a "wake growth" mechanism for the nanotube alignment along atomic steps and nanofacets. In this mechanism, the catalyst nanoparticle slides along the step or facet, leaving the nanotube behind as a wake. In addition, we showed that the combination of surface-directed growth with external forces, such as electric-field and gas flow, can lead to the simultaneous formation of complex nanotube structures, such as grids and serpentines. The "wake growth" model, which explained the growth of aligned nanotubes, could not explain the formation of nanotube serpentines. For the latter, we proposed a "falling spaghetti" mechanism, in which the nanotube first grows by a free-standing process, aligned in the direction of the gas flow, then followed by absorption on the stepped surface in an oscillatory manner, due to the competition between the drag force caused by the gas flow on the suspended

  20. Growing carbon nanotubes

    Directory of Open Access Journals (Sweden)

    Yoshinori Ando

    2004-10-01

    Full Text Available The discovery of ‘fullerenes’ added a new dimension to the knowledge of carbon science1; and the subsequent discovery of ‘carbon nanotubes’ (CNTs, the elongated fullerene added a new dimension to the knowledge of technology2;. Today, ‘nanotechnology’ is a hot topic attracting scientists, industrialists, journalists, governments, and even the general public. Nanotechnology is the creation of functional materials, devices, and systems through control of matter on the nanometer scale and the exploitation of novel phenomena and properties of matter (physical, chemical, biological, electrical, etc. at that length scale. CNTs are supposed to be a key component of nanotechnology. Almost every week a new potential application of CNTs is identified, stimulating scientists to peep into this tiny tube with ever increasing curiosity.

  1. Improved synthesis of carbon nanotubes with junctions and of single-walled carbon nanotubes

    Indian Academy of Sciences (India)

    F L Deepak; A Govindaraj; C N R Rao

    2006-01-01

    Pyrolysis of thiophene over nickel nanoparticles dispersed on silica is shown to yield Yjunction carbon nanotubes with smaller diameters than those obtained by the pyrolysis of organometallicthiophene mixtures. In the presence of water vapour, the pyrolysis of organometallic-hydrocarbon mixtures yields single-walled nanotubes, as well as relatively narrow-diameter carbon nanotubes with Y-junctions. Pyrolysis of organometallic-hydrocarbon mixtures, in the absence of water vapour, only gives nanotubes with T- and Y-junctions.

  2. Coated carbon nanotube array electrodes

    Science.gov (United States)

    Ren, Zhifeng; Wen, Jian; Chen, Jinghua; Huang, Zhongping; Wang, Dezhi

    2008-10-28

    The present invention provides conductive carbon nanotube (CNT) electrode materials comprising aligned CNT substrates coated with an electrically conducting polymer, and the fabrication of electrodes for use in high performance electrical energy storage devices. In particular, the present invention provides conductive CNTs electrode material whose electrical properties render them especially suitable for use in high efficiency rechargeable batteries. The present invention also provides methods for obtaining surface modified conductive CNT electrode materials comprising an array of individual linear, aligned CNTs having a uniform surface coating of an electrically conductive polymer such as polypyrrole, and their use in electrical energy storage devices.

  3. Carbon nanotube growth density control

    Science.gov (United States)

    Delzeit, Lance D. (Inventor); Schipper, John F. (Inventor)

    2010-01-01

    Method and system for combined coarse scale control and fine scale control of growth density of a carbon nanotube (CNT) array on a substrate, using a selected electrical field adjacent to a substrate surface for coarse scale density control (by one or more orders of magnitude) and a selected CNT growth temperature range for fine scale density control (by multiplicative factors of less than an order of magnitude) of CNT growth density. Two spaced apart regions on a substrate may have different CNT growth densities and/or may use different feed gases for CNT growth.

  4. Purification of carbon nanotube by wet oxidation; Shisshiki sanka ni yoru carbon nanotube no seisei

    Energy Technology Data Exchange (ETDEWEB)

    Morishita, K.; Takarada, T. [Gunma University, Gunma (Japan)

    1997-07-10

    In order to efficiently recover carbon nanotubes, the purification method by wet oxidation with orthoperiodic acid and perchloric acid is investigated. The reactivity of the carbonaceous material toward the acids depends on the type of carbon. Carbon nanotubes are selectively recovered under the mild oxidation conditions. The degree of purification depends on the concentration of orthoperiodic acid. It is suggested that wet oxidation is an effective method for purification of carbon nanotubes. 17 refs., 6 figs.

  5. Functionalized carbon nanotubes: biomedical applications

    Directory of Open Access Journals (Sweden)

    Vardharajula S

    2012-10-01

    Full Text Available Sandhya Vardharajula,1 Sk Z Ali,2 Pooja M Tiwari,1 Erdal Eroğlu,1 Komal Vig,1 Vida A Dennis,1 Shree R Singh11Center for NanoBiotechnology and Life Sciences Research, Alabama State University, Montgomery, AL, USA; 2Department of Microbiology, Osmania University, Hyderabad, IndiaAbstract: Carbon nanotubes (CNTs are emerging as novel nanomaterials for various biomedical applications. CNTs can be used to deliver a variety of therapeutic agents, including biomolecules, to the target disease sites. In addition, their unparalleled optical and electrical properties make them excellent candidates for bioimaging and other biomedical applications. However, the high cytotoxicity of CNTs limits their use in humans and many biological systems. The biocompatibility and low cytotoxicity of CNTs are attributed to size, dose, duration, testing systems, and surface functionalization. The functionalization of CNTs improves their solubility and biocompatibility and alters their cellular interaction pathways, resulting in much-reduced cytotoxic effects. Functionalized CNTs are promising novel materials for a variety of biomedical applications. These potential applications are particularly enhanced by their ability to penetrate biological membranes with relatively low cytotoxicity. This review is directed towards the overview of CNTs and their functionalization for biomedical applications with minimal cytotoxicity.Keywords: carbon nanotubes, cytotoxicity, functionalization, biomedical applications

  6. Selective intercalation of polymers in carbon nanotubes.

    Science.gov (United States)

    Bazilevsky, Alexander V; Sun, Kexia; Yarin, Alexander L; Megaridis, Constantine M

    2007-07-03

    A room-temperature, open-air method is devised to selectively intercalate relatively low-molecular-weight polymers (approximately 10-100 kDa) from dilute, volatile solutions into open-end, as-grown, wettable carbon nanotubes with 50-100 nm diameters. The method relies on a novel self-sustained diffusion mechanism driving polymers from dilute volatile solutions into carbon nanotubes and concentrating them there. Relatively low-molecular-weight polymers, such as poly(ethylene oxide) (PEO, 600 kDa) and poly(caprolactone) (PCL, 80 kDa), were encapsulated in graphitic nanotubes as confirmed by transmission electron microscopy, which revealed morphologies characteristic of mixtures in nanoconfinements affected by intermolecular forces. Whereas relatively small, flexible polymer molecules can conform to enter these nanotubes, larger macromolecules (approximately 1000 kDa) remain outside. The selective nature of this process is useful for filling nanotubes with polymers and could also be valuable in capping nanotubes.

  7. SYNTHESIS OF CARBON NANOTUBES FOR ACETYLENE DETECTION

    Directory of Open Access Journals (Sweden)

    M.Y. FAIZAH

    2008-04-01

    Full Text Available A gas sensor, utilizing carbon nanotubes (CNTs in a pellet form for acetylene detection has been developed. This research was carried out to investigate the absorption effect of acetylene (C2H2 towards the change of resistance of carbon nanotubes pellet as sensor signal. Source Measurement Unit (SMU was used to study the gas sensing behaviour of resistance based sensors employing carbon nanotubes pellet as the active sensing element. Studies revealed that the absorption of acetylene into the carbon nanotubes pellet resulting in increase in pellet resistance. The changes are attributed to p-type conductivity in semiconducting carbon nanotubes. Carbon nanotubes used in this research was synthesized by means of Floating Catalyst Chemical Vapor Deposition (FC-CVD method. Benzene was used as a hydrocarbon source while ferrocene as a source of catalyst with Hydrogen and Argon as carrier and purge gas respectively. From the research, it was shown that carbon nanotubes show high sensitivity towards acetylene. The highest sensitivity recorded was 1.21, 1.16 and 17.86 for S1, S2 and S3 respectively. It is expected that many applications of CNT-based sensors will be explored in future as the interest of the nanotechnology research in this field increases.

  8. A Tester for Carbon Nanotube Mode Lockers

    Science.gov (United States)

    Song, Yong-Won; Yamashita, Shinji

    2007-05-01

    We propose and demonstrate a tester for laser pulsating operation of carbon nanotubes employing a circulator with the extra degree of freedom of the second port to access diversified nanotube samples. The nanotubes are deposited onto the end facet of a dummy optical fiber by spray method that guarantees simple sample loading along with the minimized perturbation of optimized laser cavity condition. Resultant optical spectra, autocorrelation traces and pulse train of the laser outputs with qualified samples are presented.

  9. Enzymatic degradation of multiwalled carbon nanotubes.

    Science.gov (United States)

    Zhao, Yong; Allen, Brett L; Star, Alexander

    2011-09-01

    Because of their unique properties, carbon nanotubes and, in particular, multiwalled carbon nanotubes (MWNTs) have been used for the development of advanced composite and catalyst materials. Despite their growing commercial applications and increased production, the potential environmental and toxicological impacts of MWNTs are not fully understood; however, many reports suggest that they may be toxic. Therefore, a need exists to develop protocols for effective and safe degradation of MWNTs. In this article, we investigated the effect of chemical functionalization of MWNTs on their enzymatic degradation with horseradish peroxidase (HRP) and hydrogen peroxide (H(2)O(2)). We investigated HRP/H(2)O(2) degradation of purified, oxidized, and nitrogen-doped MWNTs and proposed a layer-by-layer degradation mechanism of nanotubes facilitated by side wall defects. These results provide a better understanding of the interaction between HRP and carbon nanotubes and suggest an eco-friendly way of mitigating the environmental impact of nanotubes.

  10. Carbon nanotube fiber spun from wetted ribbon

    Science.gov (United States)

    Zhu, Yuntian T; Arendt, Paul; Zhang, Xiefei; Li, Qingwen; Fu, Lei; Zheng, Lianxi

    2014-04-29

    A fiber of carbon nanotubes was prepared by a wet-spinning method involving drawing carbon nanotubes away from a substantially aligned, supported array of carbon nanotubes to form a ribbon, wetting the ribbon with a liquid, and spinning a fiber from the wetted ribbon. The liquid can be a polymer solution and after forming the fiber, the polymer can be cured. The resulting fiber has a higher tensile strength and higher conductivity compared to dry-spun fibers and to wet-spun fibers prepared by other methods.

  11. Methods for producing reinforced carbon nanotubes

    Science.gov (United States)

    Ren, Zhifen; Wen, Jian Guo; Lao, Jing Y.; Li, Wenzhi

    2008-10-28

    Methods for producing reinforced carbon nanotubes having a plurality of microparticulate carbide or oxide materials formed substantially on the surface of such reinforced carbon nanotubes composite materials are disclosed. In particular, the present invention provides reinforced carbon nanotubes (CNTs) having a plurality of boron carbide nanolumps formed substantially on a surface of the reinforced CNTs that provide a reinforcing effect on CNTs, enabling their use as effective reinforcing fillers for matrix materials to give high-strength composites. The present invention also provides methods for producing such carbide reinforced CNTs.

  12. Ordered phases of cesium in carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Jeong Won; Hwang, Ho Jung; Song, Ki Oh; Choi, Won Young; Byun, Ki Ryang [Chung-Ang University, Seoul (Korea, Republic of); Kwon, Oh Keun [Semyung University, Jecheon (Korea, Republic of); Lee, Jun Ha [Sangmyung University, Chonan (Korea, Republic of); Kim, Won Woo [Juseong College, Cheongwon (Korea, Republic of)

    2003-10-15

    We investigate the structural phases of Cs in carbon nanotubes by using a structural optimization process applied to an atomistic simulation method. As the radius of the carbon nanotubes is increased, the structures are found in various phases from an atomic strand to multishell packs composed of coaxial cylindrical shells. Both helical structures and layered structures are found. The numbers of helical atom rows composed of coaxial tubes and the orthogonal vectors of the circular rolling of a triangular network can explain the structural phases of Cs in carbon nanotubes.

  13. Microcapsule carbon nanotube devices for therapeutic applications

    Science.gov (United States)

    Kulamarva, Arun; Raja, Pavan M. V.; Bhathena, Jasmine; Chen, Hongmei; Talapatra, Saikat; Ajayan, Pulickel M.; Nalamasu, Omkaram; Prakash, Satya

    2009-01-01

    Carbon nanotubes are a new class of nanomaterials that have immense potential in the field of biomedicine. Their ability to carry large quantities of therapeutic molecules makes them prime candidates for providing targeted delivery of therapeutics for use in various diseases. However, their utility is limited due to the problems faced during their delivery to target sites. This article for the first time describes the design of a novel microcapsule carbon nanotube targeted delivery device. This device has potential in the targeted delivery of carbon nanotubes in suitable membranes along with their cargo, safely and effectively to the target loci.

  14. Highly oriented carbon nanotube papers made of aligned carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Wang Ding; Song Pengcheng; Liu Changhong; Wu Wei; Fan Shoushan [Tsinghua-Foxconn Nanotechnology Research Center and Department of Physics, Tsinghua University, Beijing 100084 (China)], E-mail: chliu@tsinghua.edu.cn

    2008-02-20

    Paper-like carbon nanotube (CNT) materials have many important applications such as in catalysts, in filtration, actuators, capacitor or battery electrodes, and so on. Up to now, the most popular way of preparing buckypapers has involved the procedures of dispersion and filtration of a suspension of CNTs. In this work, we present a simple and effective macroscopic manipulation of aligned CNT arrays called 'domino pushing' in the preparation of the aligned thick buckypapers with large areas. This simple method can efficiently ensure that most of the CNTs are well aligned tightly in the buckypaper. The initial measurements indicate that these buckypapers have better performance on thermal and electrical conductance. These buckypapers with controllable structure also have many potential applications, including supercapacitor electrodes.

  15. The electrical conduction variation in stained carbon nanotubes

    Science.gov (United States)

    Sun, Shih-Jye; Wei Fan, Jun; Lin, Chung-Yi

    2012-01-01

    Carbon nanotubes become stained from coupling with foreign molecules, especially from adsorbing gas molecules. The charge exchange, which is due to the orbital hybridization, occurred in the stained carbon nanotube induces electrical dipoles that consequently vary the electrical conduction of the nanotube. We propose a microscopic model to evaluate the electrical current variation produced by the induced electrical dipoles in a stained zigzag carbon nanotube. It is found that stronger orbital hybridization strengths and larger orbital energy differences between the carbon nanotube and the gas molecules help increasing the induced electrical dipole moment. Compared with the stain-free carbon nanotube, the induced electrical dipoles suppress the current in the nanotube. In the carbon nanotubes with induced dipoles the current increases as a result of increasing orbital energy dispersion via stronger hybridization couplings. In particular, at a fixed hybridization coupling, the current increases with the bond length for the donor-carbon nanotube but reversely for the acceptor-carbon nanotube.

  16. Methods for preparation of carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Rakov, Eduard G [D.I. Mendeleev Russian University of Chemical Technology, Moscow (Russian Federation)

    2000-01-31

    The most important methods of synthesis and purification of carbon nanotubes, a new form of material, are described. The prospects for increasing the scale of preparation processes and for more extensive application of nanotubes are evaluated. The bibliography includes 282 references.

  17. Carbon nanotubes for RF and microwaves

    OpenAIRE

    Burke, P. J.; Yu, Z; Rutherglen, C.

    2005-01-01

    In this invited overview paper we provide a brief up-to-date summary of the potential applications of carbon nanotubes for RF and microwave devices and systems. We focus in particular on the use of nanotubes as ultra-high speed interconnects in integrated circuits.

  18. Carbon nanotubes as heat dissipaters in microelectronics

    DEFF Research Database (Denmark)

    Pérez Paz, Alejandro; García-Lastra, Juan María; Markussen, Troels

    2013-01-01

    We review our recent modelling work of carbon nanotubes as potential candidates for heat dissipation in microelectronics cooling. In the first part, we analyze the impact of nanotube defects on their thermal transport properties. In the second part, we investigate the loss of thermal properties...

  19. Carbon Nanotubes for Human Space Flight

    Science.gov (United States)

    Scott, Carl D.; Files, Brad; Yowell, Leonard

    2003-01-01

    Single-wall carbon nanotubes offer the promise of a new class of revolutionary materials for space applications. The Carbon Nanotube Project at NASA Johnson Space Center has been actively researching this new technology by investigating nanotube production methods (arc, laser, and HiPCO) and gaining a comprehensive understanding of raw and purified material using a wide range of characterization techniques. After production and purification, single wall carbon nanotubes are processed into composites for the enhancement of mechanical, electrical, and thermal properties. This "cradle-to-grave" approach to nanotube composites has given our team unique insights into the impact of post-production processing and dispersion on the resulting material properties. We are applying our experience and lessons-learned to developing new approaches toward nanotube material characterization, structural composite fabrication, and are also making advances in developing thermal management materials and electrically conductive materials in various polymer-nanotube systems. Some initial work has also been conducted with the goal of using carbon nanotubes in the creation of new ceramic materials for high temperature applications in thermal protection systems. Human space flight applications such as advanced life support and fuel cell technologies are also being investigated. This discussion will focus on the variety of applications under investigation.

  20. Condensation and evaporation of new refrigerants in advanced micro-finned tubes

    Energy Technology Data Exchange (ETDEWEB)

    Laterrible, P. [Trefimetaux, 92 - Courbevoie (France); Marvillet, C. [CEA/Grenoble, Dept. de Thermohydraulique et de Physique (DTP-GRETH), 38 (France)

    1999-07-01

    Due to the European deadline for the phase-out of HCFCs, the air-conditioning manufacturers are launching new product range purpose-designed to operate on the non-ozone depleting refrigerants: R404A, R134a or R407C. The micro-finned tubes optimised for finned heat exchangers as for shell and tube evaporators and condensers are one of these recent techniques which may allow increase performance of refrigerating units the new refrigerants. Two models of thermal correlation have been established resulting from experimental measurements on single micro-fin tubes: in evaporation, the model is a modification of Gungor-Winterton which concerns the addition of nucleation and convection processes within the inner grooves. In condensation, this model is a modification of Cavallini-Zecchin correlation. With these models, it is possible to predict the behaviour micro-fin tubes in specific conditions. This permits the necessary adaptation of heat-exchangers. (authors)

  1. Coulomb drag in multiwall armchair carbon nanotubes

    DEFF Research Database (Denmark)

    Lunde, A.M.; Jauho, Antti-Pekka

    2004-01-01

    We calculate the transresistivity rho(21) between two concentric armchair nanotubes in a diffusive multiwall carbon nanotube as a function of temperature T and Fermi level epsilon(F). We approximate the tight-binding band structure by two crossing bands with a linear dispersion near the Fermi...... surface. The cylindrical geometry of the nanotubes and the different parities of the Bloch states are accounted for in the evaluation of the effective Coulomb interaction between charges in the concentric nanotubes. We find a broad peak in rho(21) as a function of temperature at roughly T similar to 0.4T...

  2. Microfabricated electroactive carbon nanotube actuators

    Science.gov (United States)

    Ahluwalia, Arti; Baughman, Ray H.; De Rossi, Danilo; Mazzoldi, Alberto; Tesconi, Mario; Tognetti, Alessandro; Vozzi, Giovanni

    2001-07-01

    A variety of microfabrication techniques have been developed at the University of Pisa. They are based either on pressure or piston actuated microsyringes or modified ink-jet printers. This work present the results of a study aimed at fabricating carbon nanotube (NT) actuators using micro-syringes. In order to prevent the nanotubes from aggregating into clumps, they were enclosed in a partially cross-linked polyvinylalcohol - polyallylamine matrix. After sonication the solution remained homogenously dispersed for about 40 minutes, which was sufficient time for deposition. Small strips of NT, about 5 mm across and 15 mm long were deposited. Following deposition, the films were baked at 80 degree(s)C and their thickness, impedance and mechanical resistance measured. The results indicate that 50 minutes of baking time is sufficient to give a constant resistivity of 1.12 x 10-2 (Omega) m per layer similar to a typical semiconductor, and each layer has a thickness of about 6 micrometers .

  3. Flightweight Carbon Nanotube Magnet Technology

    Science.gov (United States)

    Chapman, J. N.; Schmidt, H. J.; Ruoff, R. S.; Chandrasekhar, V.; Dikin, D. A.; Litchford, R. J.

    2003-01-01

    Virtually all plasma-based systems for advanced airborne/spaceborne propulsion and power depend upon the future availability of flightweight magnet technology. Unfortunately, current technology for resistive and superconducting magnets yields system weights that tend to counteract the performance advantages normally associated with advanced plasma-based concepts. The ongoing nanotechnology revolution and the continuing development of carbon nanotubes (CNT), however, may ultimately relieve this limitation in the near future. Projections based on recent research indicate that CNTs may achieve current densities at least three orders of magnitude larger than known superconductors and mechanical strength two orders of magnitude larger than steel. In fact, some published work suggests that CNTs are superconductors. Such attributes imply a dramatic increase in magnet performance-to-weight ratio and offer real hope for the construction of true flightweight magnets. This Technical Publication reviews the technology status of CNTs with respect to potential magnet applications and discusses potential techniques for using CNT wires and ropes as a winding material and as an integral component of the containment structure. The technology shortfalls are identified and a research and technology strategy is described that addresses the following major issues: (1) Investigation and verification of mechanical and electrical properties, (2) development of tools for manipulation and fabrication on the nanoscale, (3) continuum/molecular dynamics analysis of nanotube behavior when exposed to practical bending and twisting loads, and (4) exploration of innovative magnet fabrication techniques that exploit the natural attributes of CNTs.

  4. Modification of carbon nanotubes and synthesis of polymeric composites involving the nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Badamshina, E R; Gafurova, M P; Estrin, Yakov I [Institute of Problems of Chemical Physics, Russian Academy of Sciences, Chernogolovka, Moscow Region (Russian Federation)

    2010-12-29

    The results of studies, mainly published in recent years, on modification of carbon nanotubes and design of composites with these nanotubes for the manufacture of new-generation materials are generalized and analyzed. The methods of modification of the nanotubes by low- and high-molecular compounds and methods of polymer modification by carbon nanotubes are considered. Data on the properties of modified nanotubes are presented. The current and potential applications of materials based on the nanotubes are indicated.

  5. Purification of Carbon Nanotubes: Alternative Methods

    Science.gov (United States)

    Files, Bradley; Scott, Carl; Gorelik, Olga; Nikolaev, Pasha; Hulse, Lou; Arepalli, Sivaram

    2000-01-01

    Traditional carbon nanotube purification process involves nitric acid refluxing and cross flow filtration using surfactant TritonX. This is believed to result in damage to nanotubes and surfactant residue on nanotube surface. Alternative purification procedures involving solvent extraction, thermal zone refining and nitric acid refiuxing are used in the current study. The effect of duration and type of solvent to dissolve impurities including fullerenes and P ACs (polyaromatic compounds) are monitored by nuclear magnetic reasonance, high performance liquid chromatography, and thermogravimetric analysis. Thermal zone refining yielded sample areas rich in nanotubes as seen by scanning electric microscopy. Refluxing in boiling nitric acid seem to improve the nanotube content. Different procedural steps are needed to purify samples produced by laser process compared to arc process. These alternative methods of nanotube purification will be presented along with results from supporting analytical techniques.

  6. Deconvoluting hepatic processing of carbon nanotubes

    Science.gov (United States)

    Alidori, Simone; Bowman, Robert L.; Yarilin, Dmitry; Romin, Yevgeniy; Barlas, Afsar; Mulvey, J. Justin; Fujisawa, Sho; Xu, Ke; Ruggiero, Alessandro; Riabov, Vladimir; Thorek, Daniel L. J.; Ulmert, Hans David S.; Brea, Elliott J.; Behling, Katja; Kzhyshkowska, Julia; Manova-Todorova, Katia; Scheinberg, David A.; McDevitt, Michael R.

    2016-07-01

    Single-wall carbon nanotubes present unique opportunities for drug delivery, but have not advanced into the clinic. Differential nanotube accretion and clearance from critical organs have been observed, but the mechanism not fully elucidated. The liver has a complex cellular composition that regulates a range of metabolic functions and coincidently accumulates most particulate drugs. Here we provide the unexpected details of hepatic processing of covalently functionalized nanotubes including receptor-mediated endocytosis, cellular trafficking and biliary elimination. Ammonium-functionalized fibrillar nanocarbon is found to preferentially localize in the fenestrated sinusoidal endothelium of the liver but not resident macrophages. Stabilin receptors mediate the endocytic clearance of nanotubes. Biocompatibility is evidenced by the absence of cell death and no immune cell infiltration. Towards clinical application of this platform, nanotubes were evaluated for the first time in non-human primates. The pharmacologic profile in cynomolgus monkeys is equivalent to what was reported in mice and suggests that nanotubes should behave similarly in humans.

  7. Carbon Nanotube Composites: Strongest Engineering Material Ever?

    Science.gov (United States)

    Mayeaux, Brian; Nikolaev, Pavel; Proft, William; Nicholson, Leonard S. (Technical Monitor)

    1999-01-01

    The primary goal of the carbon nanotube project at Johnson Space Center (JSC) is to fabricate structural materials with a much higher strength-to-weight ratio than any engineered material today, Single-wall nanotubes present extraordinary mechanical properties along with new challenges for materials processing. Our project includes nanotube production, characterization, purification, and incorporation into applications studies. Now is the time to move from studying individual nanotubes to applications work. Current research at JSC focuses on structural polymeric materials to attempt to lower the weight of spacecraft necessary for interplanetary missions. These nanoscale fibers present unique new challenges to composites engineers. Preliminary studies show good nanotube dispersion and wetting by the epoxy materials. Results of tensile strength tests will also be reported. Other applications of nanotubes are also of interest for energy storage, gas storage, nanoelectronics, field emission, and biomedical uses.

  8. Functionalized carbon nanotubes: biomedical applications.

    Science.gov (United States)

    Vardharajula, Sandhya; Ali, Sk Z; Tiwari, Pooja M; Eroğlu, Erdal; Vig, Komal; Dennis, Vida A; Singh, Shree R

    2012-01-01

    Carbon nanotubes (CNTs) are emerging as novel nanomaterials for various biomedical applications. CNTs can be used to deliver a variety of therapeutic agents, including biomolecules, to the target disease sites. In addition, their unparalleled optical and electrical properties make them excellent candidates for bioimaging and other biomedical applications. However, the high cytotoxicity of CNTs limits their use in humans and many biological systems. The biocompatibility and low cytotoxicity of CNTs are attributed to size, dose, duration, testing systems, and surface functionalization. The functionalization of CNTs improves their solubility and biocompatibility and alters their cellular interaction pathways, resulting in much-reduced cytotoxic effects. Functionalized CNTs are promising novel materials for a variety of biomedical applications. These potential applications are particularly enhanced by their ability to penetrate biological membranes with relatively low cytotoxicity. This review is directed towards the overview of CNTs and their functionalization for biomedical applications with minimal cytotoxicity.

  9. Carbon Nanotube Tape Vibrating Gyroscope

    Science.gov (United States)

    Tucker, Dennis Stephen (Inventor)

    2016-01-01

    A vibrating gyroscope includes a piezoelectric strip having length and width dimensions. The piezoelectric strip includes a piezoelectric material and carbon nanotubes (CNTs) substantially aligned and polled along the strip's length dimension. A spindle having an axis of rotation is coupled to the piezoelectric strip. The axis of rotation is parallel to the strip's width dimension. A first capacitance sensor is mechanically coupled to the spindle for rotation therewith. The first capacitance sensor is positioned at one of the strip's opposing ends and is spaced apart from one of the strip's opposing faces. A second capacitance sensor is mechanically coupled to the spindle for rotation therewith. The second capacitance sensor is positioned at another of the strip's opposing ends and is spaced apart from another of the strip's opposing faces. A voltage source applies an AC voltage to the piezoelectric strip.

  10. Aligned carbon nanotubes for nanoelectronics

    Science.gov (United States)

    Choi, Won Bong; Bae, Eunju; Kang, Donghun; Chae, Soodoo; Cheong, Byung-ho; Ko, Ju-hye; Lee, Eungmin; Park, Wanjun

    2004-10-01

    We discuss the central issues to be addressed for realizing carbon nanotube (CNT) nanoelectronics. We focus on selective growth, electron energy bandgap engineering and device integration. We have introduced a nanotemplate to control the selective growth, length and diameter of CNTs. Vertically aligned CNTs are synthesized for developing a vertical CNT-field effect transistor (FET). The ohmic contact of the CNT/metal interface is formed by rapid thermal annealing. Diameter control, synthesis of Y-shaped CNTs and surface modification of CNTs open up the possibility for energy bandgap modulation. The concepts of an ultra-high density transistor based on the vertical-CNT array and a nonvolatile memory based on the top gate structure with an oxide-nitride-oxide charge trap are also presented. We suggest that the deposited memory film can be used for the quantum dot storage due to the localized electric field created by a nano scale CNT-electron channel.

  11. Carbon nanotubes – becoming clean

    Directory of Open Access Journals (Sweden)

    Nicole Grobert

    2007-01-01

    Full Text Available Carbon nanotubes (CNTs are now well into their teenage years. Early on, theoretical predictions and experimental data showed that CNTs possess chemical and mechanical properties that exceed those of many other materials. This has triggered intense research into CNTs. A variety of production methods for CNTs have been developed; chemical modification, functionalization, filling, and doping have been achieved; and manipulation, separation, and characterization of individual CNTs is now possible. Today, products containing CNTs range from tennis rackets and golf clubs to vehicle fenders, X-ray tubes, and Li ion batteries. Breakthroughs for CNT-based technologies are anticipated in the areas of nanoelectronics, biotechnology, and materials science. In this article, I review the current situation in CNT production and highlight the importance of clean CNT material for the success of future applications.

  12. Carbon nanotube polymer composition and devices

    Science.gov (United States)

    Liu, Gao; Johnson, Stephen; Kerr, John B.; Minor, Andrew M.; Mao, Samuel S.

    2011-06-14

    A thin film device and compound having an anode, a cathode, and at least one light emitting layer between the anode and cathode, the at least one light emitting layer having at least one carbon nanotube and a conductive polymer.

  13. Carbon nanotube heat-exchange systems

    Science.gov (United States)

    Hendricks, Terry Joseph; Heben, Michael J.

    2008-11-11

    A carbon nanotube heat-exchange system (10) and method for producing the same. One embodiment of the carbon nanotube heat-exchange system (10) comprises a microchannel structure (24) having an inlet end (30) and an outlet end (32), the inlet end (30) providing a cooling fluid into the microchannel structure (24) and the outlet end (32) discharging the cooling fluid from the microchannel structure (24). At least one flow path (28) is defined in the microchannel structure (24), fluidically connecting the inlet end (30) to the outlet end (32) of the microchannel structure (24). A carbon nanotube structure (26) is provided in thermal contact with the microchannel structure (24), the carbon nanotube structure (26) receiving heat from the cooling fluid in the microchannel structure (24) and dissipating the heat into an external medium (19).

  14. A Thermal Model for Carbon Nanotube Interconnects

    Directory of Open Access Journals (Sweden)

    Clay Mayberry

    2013-04-01

    Full Text Available In this work, we have studied Joule heating in carbon nanotube based very large scale integration (VLSI interconnects and incorporated Joule heating influenced scattering in our previously developed current transport model. The theoretical model explains breakdown in carbon nanotube resistance which limits the current density. We have also studied scattering parameters of carbon nanotube (CNT interconnects and compared with the earlier work. For 1 µm length single-wall carbon nanotube, 3 dB frequency in S12 parameter reduces to ~120 GHz from 1 THz considering Joule heating. It has been found that bias voltage has little effect on scattering parameters, while length has very strong effect on scattering parameters.

  15. Fabrication of porous carbon nanotube network.

    Science.gov (United States)

    Su, Jun-Wei; Fu, Shu-Juan; Gwo, Shangjr; Lin, Kuan-Jiuh; Lin, Kuna-Jiuh

    2008-11-21

    We used the spin-coating method combined with ultrasonic atomization as a continuous, one-step process to generate a two-dimensional honeycomb network that was constructed from pure multi-walled carbon nanotubes.

  16. Self Assembled Carbon Nanotube Enhanced Ultracapacitors Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of this NASA STTR program is to develop single wall carbon nanotube (SWCNT) based ultracapacitors for energy storage devices (ESD) application, using...

  17. Piezoresistive Sensors Based on Carbon Nanotube Films

    Institute of Scientific and Technical Information of China (English)

    L(U) Jian-wei; WANG Wan-lu; LIAO Ke-jun; WANG Yong-tian; LIU CHang-lin; Zeng Qing-gao

    2005-01-01

    Piezoresistive effect of carbon nanotube films was investigated by a three-point bending test.Carbon nanotubes were synthesized by hot filament chemical vapor deposition.The experimental results showed that the carbon nanotubes have a striking piezoresistive effect.The relative resistance was changed from 0 to 10.5×10-2 and 3.25×10-2 for doped and undoped films respectively at room temperature when the microstrain under stress from 0 to 500. The gauge factors for doped and undoped carbon nanotube films under 500 microstrain were about 220 and 67 at room temperature, respectively, exceeding that of polycrystalline silicon (30) at 35℃.The origin of the resistance changes in the films may be attributed to a strain-induced change in the band gap for the doped tubes and the defects for the undoped tubes.

  18. Controlled Deposition and Alignment of Carbon Nanotubes

    Science.gov (United States)

    Smits, Jan M. (Inventor); Wincheski, Russell A. (Inventor); Patry, JoAnne L. (Inventor); Watkins, Anthony Neal (Inventor); Jordan, Jeffrey D. (Inventor)

    2012-01-01

    A carbon nanotube (CNT) attraction material is deposited on a substrate in the gap region between two electrodes on the substrate. An electric potential is applied to the two electrodes. The CNT attraction material is wetted with a solution defined by a carrier liquid having carbon nanotubes (CNTs) suspended therein. A portion of the CNTs align with the electric field and adhere to the CNT attraction material. The carrier liquid and any CNTs not adhered to the CNT attraction material are then removed.

  19. Carbon nanotube temperature and pressure sensors

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, Ilia N.; Geohegan, David B.

    2016-12-13

    The present invention, in one embodiment, provides a method of measuring pressure or temperature using a sensor including a sensor element composed of a plurality of carbon nanotubes. In one example, the resistance of the plurality of carbon nanotubes is measured in response to the application of temperature or pressure. The changes in resistance are then recorded and correlated to temperature or pressure. In one embodiment, the present invention provides for independent measurement of pressure or temperature using the sensors disclosed herein.

  20. Carbon nanotube temperature and pressure sensors

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, Ilia N.; Geohegan, David B.

    2016-11-15

    The present invention, in one embodiment, provides a method of measuring pressure or temperature using a sensor including a sensor element composed of a plurality of carbon nanotubes. In one example, the resistance of the plurality of carbon nanotubes is measured in response to the application of temperature or pressure. The changes in resistance are then recorded and correlated to temperature or pressure. In one embodiment, the present invention provides for independent measurement of pressure or temperature using the sensors disclosed herein.

  1. Carbon nanotube temperature and pressure sensors

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, Ilia N.; Geohegan, David B.

    2016-10-25

    The present invention, in one embodiment, provides a method of measuring pressure or temperature using a sensor including a sensor element composed of a plurality of carbon nanotubes. In one example, the resistance of the plurality of carbon nanotubes is measured in response to the application of temperature or pressure. The changes in resistance are then recorded and correlated to temperature or pressure. In one embodiment, the present invention provides for independent measurement of pressure or temperature using the sensors disclosed herein.

  2. [Hygienic evaluation of multilayer carbon nanotubes].

    Science.gov (United States)

    Haliullin, T O; Zalyalov, R R; Shvedova, A A; Tkachov, A G

    2015-01-01

    The authors demonstrate that traditional methods evaluating work conditions on contemporary innovative enterprises producing nanomaterials assess these conditions as harmless and safe. At the same time, special investigation methods enable to reveal new hazards for workers' health: the study results prove that workers engaged into multilayer carbon nanotubes production are exposed to multilayer carbon nanotubes aerosols in concentrations exceeding internationally acceptable levels of 1 μg/ml (NIOSH)--that can harm the workers' health.

  3. Carbon nanotube temperature and pressure sensors

    Science.gov (United States)

    Ivanov, Ilia N; Geohegan, David Bruce

    2013-10-29

    The present invention, in one embodiment, provides a method of measuring pressure or temperature using a sensor including a sensor element composed of a plurality of carbon nanotubes. In one example, the resistance of the plurality of carbon nanotubes is measured in response to the application of temperature or pressure. The changes in resistance are then recorded and correlated to temperature or pressure. In one embodiment, the present invention provides for independent measurement of pressure or temperature using the sensors disclosed herein.

  4. Carbon nanotubes field effect transistors biosensors

    OpenAIRE

    Martínez, M.T.; Tseng, Y. C.; Ormategui, N.; Loinaz, I.; Eritja Casadellà, Ramón; Salvador, Juan Pablo; Marco, María Pilar; Bokor, J.

    2012-01-01

    [EN] Carbon nanotube transistor arrays (CNTFETs) were used as biosensors to detect NA hybridization and to recognize two anabolic steroids, stanozolol (Stz) and methylboldenone (MB). Single strand DNA and antibodies specific for STz and MB were immobilized on the carbon nanotubes (CNTs) in situ in the device using two different approaches: direct noncovalent bonding of antibodies to the devices and covalently trough a polymer previously attached to the CNTFETs. A new approach to ensure specif...

  5. Filling of carbon nanotubes and nanofibres

    Directory of Open Access Journals (Sweden)

    Reece D. Gately

    2015-02-01

    Full Text Available The reliable production of carbon nanotubes and nanofibres is a relatively new development, and due to their unique structure, there has been much interest in filling their hollow interiors. In this review, we provide an overview of the most common approaches for filling these carbon nanostructures. We highlight that filled carbon nanostructures are an emerging material for biomedical applications.

  6. ON THE CONTINUUM MODELING OF CARBON NANOTUBES

    Institute of Scientific and Technical Information of China (English)

    张鹏; 黄永刚; Philippe H.Geubelle; 黄克智

    2002-01-01

    We have recently proposed a nanoscale continuum theory for carbonnanotubes. The theory links continuum analysis with atomistic modeling by incor-porating interatomic potentials and atomic structures of carbon nanotubes directlyinto the constitutive law. Here we address two main issues involved in setting upthe nanoscale continuum theory for carbon nanotubes, namely the multi-body in-teratomic potentials and the lack of centrosymmetry in the nanotube structure. Weexplain the key ideas behind these issues in establishing a nanoscale continuum theoryin terms of interatomic potentials and atomic structures.

  7. Method for nano-pumping using carbon nanotubes

    Science.gov (United States)

    Insepov, Zeke; Hassanein, Ahmed

    2009-12-15

    The present invention relates generally to the field of nanotechnology, carbon nanotubes and, more specifically, to a method and system for nano-pumping media through carbon nanotubes. One preferred embodiment of the invention generally comprises: method for nano-pumping, comprising the following steps: providing one or more media; providing one or more carbon nanotubes, the one or more nanotubes having a first end and a second end, wherein said first end of one or more nanotubes is in contact with the media; and creating surface waves on the carbon nanotubes, wherein at least a portion of the media is pumped through the nanotube.

  8. Fast readout of carbon nanotube mechanical resonators

    Science.gov (United States)

    Meerwaldt, Harold; Singh, Vibhor; Schneider, Ben; Schouten, Raymond; van der Zant, Herre; Steele, Gary

    2013-03-01

    We perform fast readout measurements of carbon nanotube mechanical resonators. Using an electronic mixing scheme, we can detect the amplitude of the mechanical motion with an intermediate frequency (IF) of 46 MHz and a timeconstant of 1 us, up to 5 orders of magnitude faster than before. Previous measurements suffered from a low bandwidth due to the combination of the high resistance of the carbon nanotube and a large stray capacitance. We have increased the bandwidth significantly by using a high-impedance, close-proximity HEMT amplifier. The increased bandwidth should allow us to observe the nanotube's thermal motion and its transient response, approaching the regime of real-time detection of the carbon nanotube's mechanical motion.

  9. Manipulation and cutting of carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Nanomanipulation plays an important role in nanofabrication, it is also a technology necessary in exploring the secrets of nanoworld, and it thus beco mesa start point to research future nanomachine. In this study, manipulation and cutting of carbon nanotubes have been conducted in order to examine whether we can move a nanocomponent from one site to another by using the tip of atomic fo rce microscope (AFM). The technique may also be valuable for providing the const ructive materials of nanofabrication. While exploring the method for manipulatin g and cutting of nanotubes, some new phenomena have been observed during the process. Results show that carbon nanotubes present a feature of deformation combin ing bending and distortion when subjected to large mechanical forces exerted by the tip of AFM. In special cases, long carbon nanotubes can be cut into two part s, by which we can remove the part where crystal lattice is flawed, and therefor e a perfect nanocomponent can be obtained.

  10. Static and dynamic wetting measurements of single carbon nanotubes.

    Science.gov (United States)

    Barber, Asa H; Cohen, Sidney R; Wagner, H Daniel

    2004-05-07

    Individual carbon nanotubes were immersed and removed from various organic liquids using atomic force microscopy. The carbon nanotube-liquid interactions could be monitored in situ, and accurate measurements of the contact angle between liquids and the nanotube surface were made. These wetting data were used to produce Owens and Wendt plots giving the dispersive and polar components of the nanotube surface.

  11. Polymerization initated at sidewalls of carbon nanotubes

    Science.gov (United States)

    Tour, James M. (Inventor); Hudson, Jared L. (Inventor); Krishnamoorti, Ramanan (Inventor); Yurekli, Koray (Inventor); Mitchell, Cynthia A. (Inventor)

    2011-01-01

    The present invention is directed to aryl halide (such as aryl bromide) functionalized carbon nanotubes that can be utilized in anionic polymerization processes to form polymer-carbon nanotube materials with improved dispersion ability in polymer matrices. In this process the aryl halide is reacted with an alkyllithium species or is reacted with a metal to replace the aryl-bromine bond with an aryl-lithium or aryl-metal bond, respectively. It has further been discovered that other functionalized carbon nanotubes, after deprotonation with a deprotonation agent, can similarly be utilized in anionic polymerization processes to form polymer-carbon nanotube materials. Additionally or alternatively, a ring opening polymerization process can be performed. The resultant materials can be used by themselves due to their enhanced strength and reinforcement ability when compared to their unbound polymer analogs. Additionally, these materials can also be blended with pre-formed polymers to establish compatibility and enhanced dispersion of nanotubes in otherwise hard to disperse matrices resulting in significantly improved material properties. The resultant polymer-carbon nanotube materials can also be used in drug delivery processes due to their improved dispersion ability and biodegradability, and can also be used for scaffolding to promote cellular growth of tissue.

  12. Enhancenment of In-tube Condensation of Nonazeotropic Refrigerant Mixtures with a Micro-fin Tube

    Science.gov (United States)

    Koyama, Shigeru; Gao, Lei; Hujii, Tetsu

    Condensation heat transfer and pressure drop characteristics of nonazeotropic refrigerant mixtures (NARMs) of HCFC22 and CFC114 inside horizontal smooth and micro-fin tubes are experimentally investigated. The local Nusselt number for both tubes based on the temperature difference between bulk refrigerant and tube wall is compared. Data for the micro-fin tube are about 50% higher than those for the smooth tube in both cases of pure refrigerants and NARMs. In case of NARMs, however, the decrease of Nesselt number due to vapor mass transfer resistance is observed for the micro-fin tube as well as for the smooth tube. By assuming that heat transfer characteristics of the condensate of NARMs are similar to those for pure refrigerants, the vapor mass transfer coefficient of NARMs is evaluated. Comparison of frictional pressure drop for both tubes is also performed in the Lockharte-Martinelli relation. Data for the micro-fin tube are higer than those for the smooth tube. The maximum increase of the frictional pressure drop is about 30%.

  13. Oscillatory characteristics of carbon nanotubes inside carbon nanotube bundles

    Science.gov (United States)

    Ansari, R.; Alipour, A.; Sadeghi, F.

    2012-12-01

    This article presents a comprehensive study on the mechanics of carbon nanotubes (CNTs) oscillating in CNT bundles. Using the continuum approximation along with Lennard-Jones (LJ) potential function, new semi-analytical expressions in terms of double integrals are presented to evaluate van der Waals (vdW) potential energy and interaction force upon which the equation of motion is directly solved. The obtained potential expression enables one to arrive at a new semi-analytical formula for the exact evaluation of oscillation frequency. Also, an algebraic frequency formula is extracted on the basis of the simplifying assumption of constant vdW force. Based on the present expressions, a thorough study on various aspects of operating frequencies under different system parameters is given, which permits fresh insight into the problem. The strong dependence of oscillation frequency on system parameters, such as the extrusion distance and initial velocity of the core as initial conditions for the motion is indicated. Interestingly, a specific initial velocity is found at which the oscillation frequency is independent of the core length. In addition, a relation between this specific initial velocity and the escape velocity is disclosed.

  14. 75 FR 56880 - Multi-Walled Carbon Nanotubes and Single-Walled Carbon Nanotubes; Significant New Use Rules

    Science.gov (United States)

    2010-09-17

    ... structural characteristics entitled ``Material Characterization of Carbon Nanotubes for Molecular Identity... AGENCY 40 CFR Parts 9 and 721 RIN 2070-AB27 Multi-Walled Carbon Nanotubes and Single-Walled Carbon...). The two chemical substances are identified generically as multi-walled carbon nanotubes (MWCNT) (PMN...

  15. Carbon nanotube ecotoxicity in amphibians: assessment of multiwalled carbon nanotubes and comparison with double-walled carbon nanotubes.

    Science.gov (United States)

    Mouchet, Florence; Landois, Perine; Puech, Pascal; Pinelli, Eric; Flahaut, Emmanuel; Gauthier, Laury

    2010-08-01

    The potential impact of industrial multiwalled carbon nanotubes (MWNTs) was investigated under normalized laboratory conditions according to the International Standard micronucleus assay ISO 21427-1 for 12 days of half-static exposure to 0.1, 1, 10 and 50 mg/l of MWNTs in water. Three different end points were carried out for 12 days of exposure: mortality, growth inhibition and micronuclei induction in erythrocytes of the circulating blood of larvae. Raman spectroscopy analysis was used to study the presence of carbon nanotubes in the biological samples. Considering the high diversity of carbon nanotubes according to their different characteristics, MWNTs were analyzed in Xenopus larvae, comparatively to double-walled carbon nanotubes used in a previous study in similar conditions. Growth inhibition in larvae exposed to 50 mg/l of MWNTs was evidenced; however, no genetoxicity (micronucleus assay) was noticed, at any concentration. Carbon nanotube localization in the larvae leads to different possible hypothesis of mechanisms explaining toxicity in Xenopus.

  16. Carbon Nanotube-Based Synthetic Gecko Tapes

    Science.gov (United States)

    Dhinojwala, Ali

    2008-03-01

    Wall-climbing geckos have unique ability to attach to different surfaces without the use of any viscoelastic glues. On coming in contact with any surface, the micron-size gecko foot-hairs deform, enabling molecular contact over large areas, thus translating weak van der Waals (vdW) interactions into enormous shear forces. We will present our recent results on the development of synthetic gecko tape using aligned carbon nanotubes to mimic the keratin hairs found on gecko feet. The patterned carbon nanotube-based gecko tape can support a shear stress (36 N/cm^2) nearly four times higher than the gecko foot and sticks to a variety of surfaces, including Teflon. Both the micron-size setae (replicated by nanotube bundles) and nanometer-size spatulas (individual nanotubes) are necessary to achieve macroscopic shear adhesion and to translate the weak vdW interactions into high shear forces. The carbon nanotube based tape offers an excellent synthetic option as a dry conductive reversible adhesive in microelectronics, robotics and space applications. The mechanism behind these large shear forces and self-cleaning properties of these carbon nanotube based synthetic gecko tapes will be discussed. This work was performed in collaboration with graduate students Liehui Ge, and Sunny Sethi, and collaborators from RPI; Lijie Ci and Professor Pulickel Ajayan.

  17. A carbon nanotube wall membrane for water treatment.

    Science.gov (United States)

    Lee, Byeongho; Baek, Youngbin; Lee, Minwoo; Jeong, Dae Hong; Lee, Hong H; Yoon, Jeyong; Kim, Yong Hyup

    2015-05-14

    Various forms of carbon nanotubes have been utilized in water treatment applications. The unique characteristics of carbon nanotubes, however, have not been fully exploited for such applications. Here we exploit the characteristics and corresponding attributes of carbon nanotubes to develop a millimetre-thick ultrafiltration membrane that can provide a water permeability that approaches 30,000 l m(-2) h(-1) bar(-1), compared with the best water permeability of 2,400 l m(-2) h(-1) bar(-1) reported for carbon nanotube membranes. The developed membrane consists only of vertically aligned carbon nanotube walls that provide 6-nm-wide inner pores and 7-nm-wide outer pores that form between the walls of the carbon nanotubes when the carbon nanotube forest is densified. The experimental results reveal that the permeance increases as the pore size decreases. The carbon nanotube walls of the membrane are observed to impede bacterial adhesion and resist biofilm formation.

  18. A Review: Carbon Nanotube-Based Piezoresistive Strain Sensors

    Directory of Open Access Journals (Sweden)

    Waris Obitayo

    2012-01-01

    Full Text Available The use of carbon nanotubes for piezoresistive strain sensors has acquired significant attention due to its unique electromechanical properties. In this comprehensive review paper, we discussed some important aspects of carbon nanotubes for strain sensing at both the nanoscale and macroscale. Carbon nanotubes undergo changes in their band structures when subjected to mechanical deformations. This phenomenon makes them applicable for strain sensing applications. This paper signifies the type of carbon nanotubes best suitable for piezoresistive strain sensors. The electrical resistivities of carbon nanotube thin film increase linearly with strain, making it an ideal material for a piezoresistive strain sensor. Carbon nanotube composite films, which are usually fabricated by mixing small amounts of single-walled or multiwalled carbon nanotubes with selected polymers, have shown promising characteristics of piezoresistive strain sensors. Studies also show that carbon nanotubes display a stable and predictable voltage response as a function of temperature.

  19. Methods for Gas Sensing with Single-Walled Carbon Nanotubes

    Science.gov (United States)

    Kaul, Anupama B. (Inventor)

    2013-01-01

    Methods for gas sensing with single-walled carbon nanotubes are described. The methods comprise biasing at least one carbon nanotube and exposing to a gas environment to detect variation in temperature as an electrical response.

  20. Release characteristics of selected carbon nanotube polymer composites

    Science.gov (United States)

    Multi-walled carbon nanotubes (MWCNTs) are commonly used in polymer formulations to improve strength, conductivity, and other attributes. A developing concern is the potential for carbon nanotube polymer nanocomposites to release nanoparticles into the environment as the polymer ...

  1. Carbon Nanotube Reinforced Polymers for Radiation Shielding Applications

    Science.gov (United States)

    Thibeault, S. (Technical Monitor); Vaidyanathan, Ranji

    2004-01-01

    This viewgraph presentation provides information on the use of Extrusion Freeform Fabrication (EEF) for the fabrication of carbon nanotubes. The presentation addresses TGA analysis, Raman spectroscopy, radiation tests, and mechanical properties of the carbon nanotubes.

  2. Physical Removal of Metallic Carbon Nanotubes from Nanotube Network Devices Using a Thermal and Fluidic Process

    OpenAIRE

    Ford, Alexandra C.; Shaughnessy, Michael; Wong, Bryan M.; Kane, Alexander A.; Kuznetsov, Oleksandr V.; Krafcik, Karen L.; Billups, W. E.; Hauge, Robert H.; Léonard, François

    2013-01-01

    Electronic and optoelectronic devices based on thin films of carbon nanotubes are currently limited by the presence of metallic nanotubes. Here we present a novel approach based on nanotube alkyl functionalization to physically remove the metallic nanotubes from such network devices. The process relies on preferential thermal desorption of the alkyls from the semiconducting nanotubes and the subsequent dissolution and selective removal of the metallic nanotubes in chloroform. The approach is ...

  3. Carbon Nanotube Tower-Based Supercapacitor

    Science.gov (United States)

    Meyyappan, Meyya (Inventor)

    2012-01-01

    A supercapacitor system, including (i) first and second, spaced apart planar collectors, (ii) first and second arrays of multi-wall carbon nanotube (MWCNT) towers or single wall carbon nanotube (SWCNT) towers, serving as electrodes, that extend between the first and second collectors where the nanotube towers are grown directly on the collector surfaces without deposition of a catalyst and without deposition of a binder material on the collector surfaces, and (iii) a porous separator module having a transverse area that is substantially the same as the transverse area of at least one electrode, where (iv) at least one nanotube tower is functionalized to permit or encourage the tower to behave as a hydrophilic structure, with increased surface wettability.

  4. Carbon Nanotube-Based Permeable Membranes

    Energy Technology Data Exchange (ETDEWEB)

    Holt, J K; Park, H G; Bakajin, O; Noy, A; Huser, T; Eaglesham, D

    2004-04-06

    A membrane of multiwalled carbon nanotubes embedded in a silicon nitride matrix was fabricated for use in studying fluid mechanics on the nanometer scale. Characterization by fluorescent tracer diffusion and scanning electron microscopy suggests that the membrane is void-free near the silicon substrate on which it rests, implying that the hollow core of the nanotube is the only conduction path for molecular transport. Assuming Knudsen diffusion through this nanotube membrane, a maximum helium transport rate (for a pressure drop of 1 atm) of 0.25 cc/sec is predicted. Helium flow measurements of a nanoporous silicon nitride membrane, fabricated by sacrificial removal of carbon, give a flow rate greater than 1x10{sup -6} cc/sec. For viscous, laminar flow conditions, water is estimated to flow across the nanotube membrane (under a 1 atm pressure drop) at up to 2.8x10{sup -5} cc/sec (1.7 {micro}L/min).

  5. Functionalized carbon nanotubes for potential medicinal applications.

    Science.gov (United States)

    Zhang, Yi; Bai, Yuhong; Yan, Bing

    2010-06-01

    Functionalized carbon nanotubes display unique properties that enable a variety of medicinal applications, including the diagnosis and treatment of cancer, infectious diseases and central nervous system disorders, and applications in tissue engineering. These potential applications are particularly encouraged by their ability to penetrate biological membranes and relatively low toxicity. High aspect ratio, unique optical property and the likeness as small molecule make carbon nanotubes an unusual allotrope of element carbon. After functionalization, carbon nanotubes display potentials for a variety of medicinal applications, including the diagnosis and treatment of cancer, infectious diseases and central nervous system disorders, and applications in tissue engineering. These potential applications are particularly encouraged by their ability to penetrate biological membranes and relatively low toxicity.

  6. Carbon Nanotubes and Chronic Granulomatous Disease

    Directory of Open Access Journals (Sweden)

    Barbara P. Barna

    2014-06-01

    Full Text Available Use of nanomaterials in manufactured consumer products is a rapidly expanding industry and potential toxicities are just beginning to be explored. Combustion-generated multiwall carbon nanotubes (MWCNT or nanoparticles are ubiquitous in non-manufacturing environments and detectable in vapors from diesel fuel, methane, propane, and natural gas. In experimental animal models, carbon nanotubes have been shown to induce granulomas or other inflammatory changes. Evidence suggesting potential involvement of carbon nanomaterials in human granulomatous disease, has been gathered from analyses of dusts generated in the World Trade Center disaster combined with epidemiological data showing a subsequent increase in granulomatous disease of first responders. In this review we will discuss evidence for similarities in the pathophysiology of carbon nanotube-induced pulmonary disease in experimental animals with that of the human granulomatous disease, sarcoidosis.

  7. Elastomer Reinforced with Carbon Nanotubes

    Science.gov (United States)

    Hudson, Jared L.; Krishnamoorti, Ramanan

    2009-01-01

    Elastomers are reinforced with functionalized, single-walled carbon nanotubes (SWNTs) giving them high-breaking strain levels and low densities. Cross-linked elastomers are prepared using amine-terminated, poly(dimethylsiloxane) (PDMS), with an average molecular weight of 5,000 daltons, and a functionalized SWNT. Cross-link densities, estimated on the basis of swelling data in toluene (a dispersing solvent) indicated that the polymer underwent cross-linking at the ends of the chains. This thermally initiated cross-linking was found to occur only in the presence of the aryl alcohol functionalized SWNTs. The cross-link could have been via a hydrogen-bonding mechanism between the amine and the free hydroxyl group, or via attack of the amine on the ester linage to form an amide. Tensile properties examined at room temperature indicate a three-fold increase in the tensile modulus of the elastomer, with rupture and failure of the elastomer occurring at a strain of 6.5.

  8. Localized Excitons in Carbon Nanotubes.

    Science.gov (United States)

    Adamska, Lyudmyla; Doorn, Stephen K.; Tretiak, Sergei

    2015-03-01

    It has been historically known that unintentional defects in carbon nanotubes (CNTs) may fully quench the fluorescence. However, some dopants may enhance the fluorescence by one order of magnitude thus turning the CNTs, which are excellent light absorbers, in good emitters. We have correlated the experimentally observed photoluminescence spectra to the electronic structure simulations. Our experiment reveals multiple sharp asymmetric emission peaks at energies 50-300 meV red-shifted from that of the lowest bright exciton peak. Our simulations suggest an association of these peaks with deep trap states tied to different specific chemical adducts. While the wave functions of excitons in undoped CNTs are delocalized, those of the deep-trap states are strongly localized and pinned to the dopants. These findings are consistent with the experimental observation of asymmetric broadening of the deep trap emission peaks, which can result from scattering of acoustic phonons on localized excitons. Our work lays the foundation to utilize doping as a generalized route for wave function engineering and direct control of carrier dynamics in SWCNTs toward enhanced light emission properties for photonic applications.

  9. Thermal Transport in Carbon Nanotubes

    Science.gov (United States)

    Christman, Jeremy; Moore, Andrew; Khatun, Mahfuza

    2011-10-01

    Recent advances in nanostructure technology have made it possible to create small devices at the nanoscale. Carbon nanotubes (CNT's) are among the most exciting building blocks of nanotechnology. Their versatility and extremely desirable properties for electronic and other devices have driven intense research and development efforts in recent years. A review of electrical and thermal conduction of the structures will be presented. The theoretical investigation is mainly based on molecular dynamics. Green Kubo relation is used for the study of thermal conductivity. Results include kinetic energy, potential energy, heat flux autocorrelation function, and heat conduction of various CNT structures. Most of the computation and simulation has been conducted on the Beowulf cluster at Ball State University. Various software packages and tools such as Visual Molecular Dynamics (VMD), Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS), and NanoHUB, the open online resource at Purdue University have been used for the research. The work has been supported by the Indiana Academy of Science Research Fund, 2010-2011.

  10. Different Technical Applications of Carbon Nanotubes.

    Science.gov (United States)

    Abdalla, S; Al-Marzouki, F; Al-Ghamdi, Ahmed A; Abdel-Daiem, A

    2015-12-01

    Carbon nanotubes have been of great interest because of their simplicity and ease of synthesis. The novel properties of nanostructured carbon nanotubes such as high surface area, good stiffness, and resilience have been explored in many engineering applications. Research on carbon nanotubes have shown the application in the field of energy storage, hydrogen storage, electrochemical supercapacitor, field-emitting devices, transistors, nanoprobes and sensors, composite material, templates, etc. For commercial applications, large quantities and high purity of carbon nanotubes are needed. Different types of carbon nanotubes can be synthesized in various ways. The most common techniques currently practiced are arc discharge, laser ablation, and chemical vapor deposition and flame synthesis. The purification of CNTs is carried out using various techniques mainly oxidation, acid treatment, annealing, sonication, filtering chemical functionalization, etc. However, high-purity purification techniques still have to be developed. Real applications are still under development. This paper addresses the current research on the challenges that are associated with synthesis methods, purification methods, and dispersion and toxicity of CNTs within the scope of different engineering applications, energy, and environmental impact.

  11. Chemical reactions confined within carbon nanotubes.

    Science.gov (United States)

    Miners, Scott A; Rance, Graham A; Khlobystov, Andrei N

    2016-08-22

    In this critical review, we survey the wide range of chemical reactions that have been confined within carbon nanotubes, particularly emphasising how the pairwise interactions between the catalysts, reactants, transition states and products of a particular molecular transformation with the host nanotube can be used to control the yields and distributions of products of chemical reactions. We demonstrate that nanoscale confinement within carbon nanotubes enables the control of catalyst activity, morphology and stability, influences the local concentration of reactants and products thus affecting equilibria, rates and selectivity, pre-arranges the reactants for desired reactions and alters the relative stability of isomeric products. We critically evaluate the relative advantages and disadvantages of the confinement of chemical reactions inside carbon nanotubes from a chemical perspective and describe how further developments in the controlled synthesis of carbon nanotubes and the incorporation of multifunctionality are essential for the development of this ever-expanding field, ultimately leading to the effective control of the pathways of chemical reactions through the rational design of multi-functional carbon nanoreactors.

  12. Different Technical Applications of Carbon Nanotubes

    Science.gov (United States)

    Abdalla, S.; Al-Marzouki, F.; Al-Ghamdi, Ahmed A.; Abdel-Daiem, A.

    2015-09-01

    Carbon nanotubes have been of great interest because of their simplicity and ease of synthesis. The novel properties of nanostructured carbon nanotubes such as high surface area, good stiffness, and resilience have been explored in many engineering applications. Research on carbon nanotubes have shown the application in the field of energy storage, hydrogen storage, electrochemical supercapacitor, field-emitting devices, transistors, nanoprobes and sensors, composite material, templates, etc. For commercial applications, large quantities and high purity of carbon nanotubes are needed. Different types of carbon nanotubes can be synthesized in various ways. The most common techniques currently practiced are arc discharge, laser ablation, and chemical vapor deposition and flame synthesis. The purification of CNTs is carried out using various techniques mainly oxidation, acid treatment, annealing, sonication, filtering chemical functionalization, etc. However, high-purity purification techniques still have to be developed. Real applications are still under development. This paper addresses the current research on the challenges that are associated with synthesis methods, purification methods, and dispersion and toxicity of CNTs within the scope of different engineering applications, energy, and environmental impact.

  13. Edge effects in finite elongated carbon nanotubes

    CERN Document Server

    Hod, O; Scuseria, G E; Hod, Oded; Peralta, Juan E.; Scuseria, Gustavo E.

    2006-01-01

    The importance of finite-size effects for the electronic structure of long zigzag and armchair carbon nanotubes is studied. We analyze the electronic structure of capped (6,6), (8,0), and (9,0) single walled carbon nanotubes as a function of their length up to 60 nm, using a divide and conquer density functional theory approach. For the metallic nanotubes studied, most of the physical features appearing in the density of states of an infinite carbon nanotube are recovered at a length of 40 nm. The (8,0) semi-conducting nanotube studied exhibits pronounced edge effects within the energy gap that scale as the inverse of the length of the nanotube. As a result, the energy gap reduces from the value of ~1 eV calculated for the periodic system to a value of ~0.25 eV calculated for a capped 62 nm long CNT. These edge effects are expected to become negligible only at tube lengths exceeding 6 micrometers. Our results indicate that careful tailoring of the nature of the system and its capping units should be applied w...

  14. Bulk Cutting of Carbon Nanotubes Using Electron Beam Irradiation

    Science.gov (United States)

    Ziegler, Kirk J. (Inventor); Rauwald, Urs (Inventor); Hauge, Robert H. (Inventor); Schmidt, Howard K. (Inventor); Smalley, Richard E. (Inventor); Kittrell, W. Carter (Inventor); Gu, Zhenning (Inventor)

    2013-01-01

    According to some embodiments, the present invention provides a method for attaining short carbon nanotubes utilizing electron beam irradiation, for example, of a carbon nanotube sample. The sample may be pretreated, for example by oxonation. The pretreatment may introduce defects to the sidewalls of the nanotubes. The method is shown to produces nanotubes with a distribution of lengths, with the majority of lengths shorter than 100 tun. Further, the median length of the nanotubes is between about 20 nm and about 100 nm.

  15. Chitosan-mediated synthesis of carbon nanotube-gold nanohybrids

    Institute of Scientific and Technical Information of China (English)

    GRAVEL; Edmond; FOILLARD; Stéphanie; DORIS; Eric

    2010-01-01

    Metal-nanotube nanohybrids were produced by in situ synthesis and stabilization of gold nanoparticles on chitosan-functionalized carbon nanotubes.The formation of gold nanoparticles from tetrachloroauric acid was observed after only a few minutes of contact with the functionalized nanotubes,at room temperature.These results suggest that adsorption of chitosan at the surface of carbon nanotubes permits smooth reduction of the metallic salt and efficient anchoring of gold nanoparticles to the nanotubes.

  16. Effects of single-walled carbon nanotubes on lysozyme gelation.

    Science.gov (United States)

    Tardani, Franco; La Mesa, Camillo

    2014-09-01

    The possibility to disperse carbon nanotubes in biocompatible matrices has got substantial interest from the scientific community. Along this research line, the inclusion of single walled carbon nanotubes in lysozyme-based hydrogels was investigated. Experiments were performed at different nanotube/lysozyme weight ratios. Carbon nanotubes were dispersed in protein solutions, in conditions suitable for thermal gelation. The state of the dispersions was determined before and after thermal treatment. Rheology, dynamic light scattering and different microscopies investigated the effect that carbon nanotubes exert on gelation. The gelation kinetics and changes in gelation temperature were determined. The effect of carbon and lysozyme content on the gel properties was, therefore, determined. At fixed lysozyme content, moderate amounts of carbon nanotubes do not disturb the properties of hydrogel composites. At moderately high volume fractions in carbon nanotubes, the gels become continuous in both lysozyme and nanotubes. This is because percolating networks are presumably formed. Support to the above statements comes by rheology.

  17. Deposition of the platinum crystals on the carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A new technique and the affecting factors for depositing platinum on the carbon nanotubes were investigated. The results show that the deposited platinum crystals in the atmosphere of hydrogen or nitrogen have a small size and a homogeneous distribution on the surface of the carbon nanotubes. The pretreatment would decrease the platinum particles on the carbon nanotubes significantly.

  18. Transport Properties of Carbon-Nanotube/Cement Composites

    NARCIS (Netherlands)

    Han, B.; Yang, Z.; Shi, X.; Yu, X.

    2012-01-01

    This paper preliminarily investigates the general transport properties (i.e., water sorptivity, water permeability, and gas permeability) of carbon-nanotube/cement composites. Carboxyl multi-walled carbon nanotubes (MWNTs) are dispersed into cement mortar to fabricate the carbon nanotubes (CNTs) rei

  19. Interaction of pristine and functionalized carbon nanotubes with lipid membranes.

    Science.gov (United States)

    Baoukina, Svetlana; Monticelli, Luca; Tieleman, D Peter

    2013-10-10

    Carbon nanotubes are widely used in a growing number of applications. Their interactions with biological materials, cell membranes in particular, is of interest in applications including drug delivery and for understanding the toxicity of carbon nanotubes. We use extensive molecular dynamics simulations with the MARTINI model to study the interactions of model nanotubes of different thickness, length, and patterns of chemical modification with model membranes. In addition, we characterize the interactions of small bundles of carbon nanotubes with membrane models. Short pristine carbon nanotubes readily insert into membranes and adopt an orientation parallel to the plane of the membrane in the center of the membrane. Larger aggregates and functionalized nanotubes exhibit a range of possible interactions. The distribution and orientation of carbon nanotubes can be controlled by functionalizing the nanotubes. Free energy calculations provide thermodynamic insight into the preferred orientations of different nanotubes and quantify structural defects in the lipid matrix.

  20. Graphene-carbon nanotube hybrid materials and use as electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Tour, James M.; Zhu, Yu; Li, Lei; Yan, Zheng; Lin, Jian

    2016-09-27

    Provided are methods of making graphene-carbon nanotube hybrid materials. Such methods generally include: (1) associating a graphene film with a substrate; (2) applying a catalyst and a carbon source to the graphene film; and (3) growing carbon nanotubes on the graphene film. The grown carbon nanotubes become covalently linked to the graphene film through carbon-carbon bonds that are located at one or more junctions between the carbon nanotubes and the graphene film. In addition, the grown carbon nanotubes are in ohmic contact with the graphene film through the carbon-carbon bonds at the one or more junctions. The one or more junctions may include seven-membered carbon rings. Also provided are the formed graphene-carbon nanotube hybrid materials.

  1. Carbon nanotube suspensions, dispersions, & composites

    Science.gov (United States)

    Simmons, Trevor John

    Carbon Nanotubes (CNTs) are amazing structures that hold the potential to revolutionize many areas of scientific research. CNTs can be behave both as semiconductors and metals, can be grown in highly ordered arrays and patterns or in random orientation, and can be comprised of one graphene cylinder (single wall nanotube, SWNT) or several concentric graphene cylinders (multi-wall nanotube, MWNT). Although these structures are usually only a few nanometers wide, they can be grown up to centimeter lengths, and in massive quantities. CNTs can be produced in a variety of processes ranging from repeated combustion of organic material such as dried grass, arc-discharge with graphite electrodes, laser ablation of a graphitic target, to sophisticated chemical vapor deposition (CVD) techniques. CNTs are stronger than steel but lighter than aluminum, and can be more conductive than copper or semiconducting like silicon. This variety of properties has been matched by the wide variety of applications that have been developed for CNTs. Many of these applications have been limited by the inability of researchers to tame these structures, and incorporating CNTs into existing technologies can be exceedingly difficult and prohibitively expensive. It is therefore the aim of the current study to develop strategies for the solution processing and deposition of CNTs and CNT-composites, which will enable the use of CNTs in existing and emerging technologies. CNTs are not easily suspended in polar solvents and are extremely hydrophobic materials, which has limited much of the solution processing to organic solvents, which also cannot afford high quality dispersions of CNTs. The current study has developed a variety of aqueous CNT solutions that employ surfactants, water-soluble polymers, or both to create suspensions of CNTs. These CNT 'ink' solutions were deposited with a variety of techniques that have afforded many interesting structures, both randomly oriented as well as highly

  2. High frequency conductivity in carbon nanotubes

    Directory of Open Access Journals (Sweden)

    S. S. Abukari

    2012-12-01

    Full Text Available We report on theoretical analysis of high frequency conductivity in carbon nanotubes. Using the kinetic equation with constant relaxation time, an analytical expression for the complex conductivity is obtained. The real part of the complex conductivity is initially negative at zero frequency and become more negative with increasing frequency, until it reaches a resonance minimum at ω ∼ ωB for metallic zigzag CNs and ω < ωB for armchair CNs. This resonance enhancement is indicative for terahertz gain without the formation of current instabilities induced by negative dc conductivity. We noted that due to the high density of states of conduction electrons in metallic zigzag carbon nanotubes and the specific dispersion law inherent in hexagonal crystalline structure result in a uniquely high frequency conductivity than the corresponding values for metallic armchair carbon nanotubes. We suggest that this phenomenon can be used to suppress current instabilities that are normally associated with a negative dc differential conductivity.

  3. Carbon nanotubes in neuroregeneration and repair.

    Science.gov (United States)

    Fabbro, Alessandra; Prato, Maurizio; Ballerini, Laura

    2013-12-01

    In the last decade, we have experienced an increasing interest and an improved understanding of the application of nanotechnology to the nervous system. The aim of such studies is that of developing future strategies for tissue repair to promote functional recovery after brain damage. In this framework, carbon nanotube based technologies are emerging as particularly innovative tools due to the outstanding physical properties of these nanomaterials together with their recently documented ability to interface neuronal circuits, synapses and membranes. This review will discuss the state of the art in carbon nanotube technology applied to the development of devices able to drive nerve tissue repair; we will highlight the most exciting findings addressing the impact of carbon nanotubes in nerve tissue engineering, focusing in particular on neuronal differentiation, growth and network reconstruction.

  4. Boron-Filled Hybrid Carbon Nanotubes

    Science.gov (United States)

    Patel, Rajen B.; Chou, Tsengming; Kanwal, Alokik; Apigo, David J.; Lefebvre, Joseph; Owens, Frank; Iqbal, Zafar

    2016-07-01

    A unique nanoheterostructure, a boron-filled hybrid carbon nanotube (BHCNT), has been synthesized using a one-step chemical vapor deposition process. The BHCNTs can be considered to be a novel form of boron carbide consisting of boron doped, distorted multiwalled carbon nanotubes (MWCNTs) encapsulating boron nanowires. These MWCNTs were found to be insulating in spite of their graphitic layered outer structures. While conventional MWCNTs have great axial strength, they have weak radial compressive strength, and do not bond well to one another or to other materials. In contrast, BHCNTs are shown to be up to 31% stiffer and 233% stronger than conventional MWCNTs in radial compression and have excellent mechanical properties at elevated temperatures. The corrugated surface of BHCNTs enables them to bond easily to themselves and other materials, in contrast to carbon nanotubes (CNTs). BHCNTs can, therefore, be used to make nanocomposites, nanopaper sheets, and bundles that are stronger than those made with CNTs.

  5. A review on protein functionalized carbon nanotubes.

    Science.gov (United States)

    Nagaraju, Kathyayini; Reddy, Roopa; Reddy, Narendra

    2015-12-18

    Carbon nanotubes (CNTs) have been widely recognized and used for controlled drug delivery and in various other fields due to their unique properties and distinct advantages. Both single-walled carbon nanotubes (SWCNTs) and multiwalled (MWCNTs) carbon nanotubes are used and/or studied for potential applications in medical, energy, textile, composite, and other areas. Since CNTs are chemically inert and are insoluble in water or other organic solvents, they are functionalized or modified to carry payloads or interact with biological molecules. CNTs have been preferably functionalized with proteins because CNTs are predominantly used for medical applications such as delivery of drugs, DNA and genes, and also for biosensing. Extensive studies have been conducted to understand the interactions, cytotoxicity, and potential applications of protein functionalized CNTs but contradicting results have been published on the cytotoxicity of the functionalized CNTs. This paper provides a brief review of CNTs functionalized with proteins, methods used to functionalize the CNTs, and their potential applications.

  6. Boron-Filled Hybrid Carbon Nanotubes

    Science.gov (United States)

    Patel, Rajen B.; Chou, Tsengming; Kanwal, Alokik; Apigo, David J.; Lefebvre, Joseph; Owens, Frank; Iqbal, Zafar

    2016-01-01

    A unique nanoheterostructure, a boron-filled hybrid carbon nanotube (BHCNT), has been synthesized using a one-step chemical vapor deposition process. The BHCNTs can be considered to be a novel form of boron carbide consisting of boron doped, distorted multiwalled carbon nanotubes (MWCNTs) encapsulating boron nanowires. These MWCNTs were found to be insulating in spite of their graphitic layered outer structures. While conventional MWCNTs have great axial strength, they have weak radial compressive strength, and do not bond well to one another or to other materials. In contrast, BHCNTs are shown to be up to 31% stiffer and 233% stronger than conventional MWCNTs in radial compression and have excellent mechanical properties at elevated temperatures. The corrugated surface of BHCNTs enables them to bond easily to themselves and other materials, in contrast to carbon nanotubes (CNTs). BHCNTs can, therefore, be used to make nanocomposites, nanopaper sheets, and bundles that are stronger than those made with CNTs. PMID:27460526

  7. Carbon Nanotube Bolometer for Absolute FTIR Spectroscopy

    Science.gov (United States)

    Woods, Solomon; Neira, Jorge; Tomlin, Nathan; Lehman, John

    We have developed and calibrated planar electrical-substitution bolometers which employ absorbers made from vertically-aligned carbon nanotube arrays. The nearly complete absorption of light by the carbon nanotubes from the visible range to the far-infrared can be exploited to enable a device with read-out in native units equivalent to optical power. Operated at cryogenic temperatures near 4 K, these infrared detectors are designed to have time constant near 10 ms and a noise floor of about 10 pW. Built upon a micro-machined silicon platform, each device has an integrated heater and thermometer, either a carbon nanotube thermistor or superconducting transition edge sensor, for temperature control. We are optimizing temperature-controlled measurement techniques to enable high resolution spectral calibrations using these devices with a Fourier-transform spectrometer.

  8. Carbon Nanotubes Synthesis Through Gamma Radiation

    Science.gov (United States)

    Tirado, Pablo; Garcia, Rafael; Montes, Jorge; Melendrez, Rodrigo; Barboza, Marcelino; Contreras, Oscar

    2015-03-01

    Carbon nanotubes show a great potential of applications since there discovery by Iijima in 1991[1] due to their numerous physical-chemical properties such as their high weight to strength relationship, which make them ideal to use in high resistance compound materials, and in many other applications[2] In this work, a novel method for the synthesis of carbon nanotubes is presented, starting from an ultra-thin sheet of graphite synthesized by the chemical vapor decomposition technique (CVD), using ultra high purity methane and hydrogen at 1200°C in a horizontal quartz reactor. For the synthesis of carbon nanotubes, the graphite sheets were exposed to different doses of radiation, with the objective of breaking the graphite bonds and form carbon nanotubes; a Gammacell equipment model 220 Excel was used for the purpose, which counts with a radiation source of cobalt 60, and a current radiation rate of 0.9 Gy/seconds. The time of exposure to radiation was varied in each sample, according to the desired dose of radiation in each case, afterwards the samples were characterized using the Raman spectroscopy and TEM microscopy techniques with the objective of observing the kind of nanotubes formed, their morphology and their number of defects. Results will be shown during the poster session.

  9. A carbon nanotube optical rectenna

    Science.gov (United States)

    Sharma, Asha; Singh, Virendra; Bougher, Thomas L.; Cola, Baratunde A.

    2015-12-01

    An optical rectenna—a device that directly converts free-propagating electromagnetic waves at optical frequencies to direct current—was first proposed over 40 years ago, yet this concept has not been demonstrated experimentally due to fabrication challenges at the nanoscale. Realizing an optical rectenna requires that an antenna be coupled to a diode that operates on the order of 1 PHz (switching speed on the order of 1 fs). Diodes operating at these frequencies are feasible if their capacitance is on the order of a few attofarads, but they remain extremely difficult to fabricate and to reliably couple to a nanoscale antenna. Here we demonstrate an optical rectenna by engineering metal-insulator-metal tunnel diodes, with a junction capacitance of ˜2 aF, at the tip of vertically aligned multiwalled carbon nanotubes (˜10 nm in diameter), which act as the antenna. Upon irradiation with visible and infrared light, we measure a d.c. open-circuit voltage and a short-circuit current that appear to be due to a rectification process (we account for a very small but quantifiable contribution from thermal effects). In contrast to recent reports of photodetection based on hot electron decay in a plasmonic nanoscale antenna, a coherent optical antenna field appears to be rectified directly in our devices, consistent with rectenna theory. Finally, power rectification is observed under simulated solar illumination, and there is no detectable change in diode performance after numerous current-voltage scans between 5 and 77 °C, indicating a potential for robust operation.

  10. Micromechanics of carbon nanotube turfs

    Science.gov (United States)

    Torabi, Hamid

    Complex structures consisting of intertwined, nominally vertical carbon nanotubes (CNTs) are called turfs. Unique electrical, thermal, optical, and permeability properties of these turfs have attracted growing attention during the past decade, and have rendered them as appropriate candidates for applications such as contact thermal switches. These properties are controlled by the details of the turf microstructures. Due to the application of the turfs in different fields, they are subjected to different loading conditions. Deformation changes the microstructure of a CNT turf, which results in change of effective properties. Many researchers have recently studied the collective mechanical behavior of CNT turfs to compression loading, as this behavior determines their performance. However, their complex and intertwined structure must be investigated in more details to find the relation between their deformation and their underlying morphology. Under uniform compression experiments, CNT turfs exhibit irreversible collective buckling of a layer preceded by reorientation of CNT segments. Experimentally observed independence of the buckling stress and the buckling wavelength on the turf width suggests the existence of an intrinsic material length. To investigate the relationship the macroscopic material properties and the statistical parameters describing the nano-scale geometry of the turf (tortuosity, density and connectivity) we develop a nano-scale computational model, based on the representation of CNT segments as elastica finite elements with van der Waals interactions. The virtual turfs are generated by means of a constrained random walk algorithm and subsequent relaxation. The resulting computational model is robust and is capable of modeling the collective behavior of CNTs. We first establish the dependence of statistical parameters on the computational parameters used for turf generation, then establish relationships between post-buckling stress, initial

  11. Laser ablative synthesis of carbon nanotubes

    Science.gov (United States)

    Smith, Michael W.; Jordan, Kevin; Park, Cheol

    2010-03-02

    An improved method for the production of single walled carbon nanotubes that utilizes an RF-induction heated side-pumped synthesis chamber for the production of such. Such a method, while capable of producing large volumes of carbon nanotubes, concurrently permits the use of a simplified apparatus that allows for greatly reduced heat up and cool down times and flexible flowpaths that can be readily modified for production efficiency optimization. The method of the present invention utilizes a free electron laser operating at high average and peak fluence to illuminate a rotating and translating graphite/catalyst target to obtain high yields of SWNTs without the use of a vacuum chamber.

  12. Carbon nanotubes for in vivo cancer nanotechnology

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The latest progress of using carbon nanotubes(CNTs) for in vivo cancer nanotechnology is reviewed.CNTs can be functionalized by either covalent or non-covalent chemistry to produce functional bioconjugates for many in vivo applications.In vivo behaviors and toxicology studies of CNTs are summarized,suggesting no significant toxicity of well functionalized CNTs to the treated mice.Owing to their unique chemical and physical properties,CNTs,especially single-walled carbon nanotubes(SWNTs),have been widely used for various modalities of in vivo cancer treatment and imaging.Future development of CNT-based nanomedicine may bring novel opportunities to cancer diagnosis and therapy.

  13. Piezoresistive effect in carbon nanotube films

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The piezoresistive effect of the pristine carbon nanotube (CNT) films has been studied. Carbon nanotubes were synthesized by hot filament chemical vapor deposition. The piezoresistive effect in the pristine CNT films was studied by a three-point bending test. The gauge factor for the pristine CNT films under 500 microstrains was found to be at least 65 at room temperature, and increased with temperature, exceeding that of polycrystalline silicon (30) at 35℃. The origin of the piezoresistivity in CNT films may be ascribed to a pressure-induced change in the band gap and the defects.

  14. Nanoscale atomic waveguides with suspended carbon nanotubes

    CERN Document Server

    Peano, V; Kasper, A; Egger, R

    2005-01-01

    We propose an experimentally viable setup for the realization of one-dimensional ultracold atom gases in a nanoscale magnetic waveguide formed by single doubly-clamped suspended carbon nanotubes. We show that all common decoherence and atom loss mechanisms are small guaranteeing a stable operation of the trap. Since the extremely large current densities in carbon nanotubes are spatially homogeneous, our proposed architecture allows to overcome the problem of fragmentation of the atom cloud. Adding a second nanowire allows to create a double-well potential with a moderate tunneling barrier which is desired for tunneling and interference experiments with the advantage of tunneling distances being in the nanometer regime.

  15. Carbon nanotube based transparent conductive thin films.

    Science.gov (United States)

    Yu, X; Rajamani, R; Stelson, K A; Cui, T

    2006-07-01

    Carbon nanotube (CNT) based optically transparent and electrically conductive thin films are fabricated on plastic substrates in this study. Single-walled carbon nanotubes (SWNTs) are chemically treated with a mixture of concentrated sulfuric acid and nitric acid before being dispersed in aqueous surfactant-contained solutions. SWNT thin films are prepared from the stable SWNT solutions using wet coating techniques. The 100 nm thick SWNT thin film exhibits a surface resistivity of 6 kohms/square nanometer with an average transmittance of 88% on the visible light range, which is three times better than the films prepared from the high purity as-received SWNTs.

  16. Quantum transport in carbon nanotubes

    DEFF Research Database (Denmark)

    Laird, Edward A.; Kuemmeth, Ferdinand; Steele, Gary A.;

    2015-01-01

    by recent advances in theory. As well as the well-understood overall picture, we also state clearly open questions for the field. These advances position nanotubes as a leading system for the study of spin and valley physics in one dimension where electronic disorder and hyperfine interaction can both...... and valley degrees of freedom. This review describes the modern understanding of transport through nanotube devices. Unlike conventional semiconductors, electrons in nanotubes have two angular momentum quantum numbers, arising from spin and from valley freedom. We focus on the interplay between the two....... In single quantum dots defined in short lengths of nanotube, the energy levels associated with each degree of freedom, and the spin-orbit coupling between them, are revealed by Coulomb blockade spectroscopy. In double quantum dots, the combination of quantum numbers modifies the selection rules of Pauli...

  17. A tunable carbon nanotube electromechanical oscillator

    Science.gov (United States)

    Sazonova, Vera; Yaish, Yuval; Üstünel, Hande; Roundy, David; Arias, Tomás A.; McEuen, Paul L.

    2004-09-01

    Nanoelectromechanical systems (NEMS) hold promise for a number of scientific and technological applications. In particular, NEMS oscillators have been proposed for use in ultrasensitive mass detection, radio-frequency signal processing, and as a model system for exploring quantum phenomena in macroscopic systems. Perhaps the ultimate material for these applications is a carbon nanotube. They are the stiffest material known, have low density, ultrasmall cross-sections and can be defect-free. Equally important, a nanotube can act as a transistor and thus may be able to sense its own motion. In spite of this great promise, a room-temperature, self-detecting nanotube oscillator has not been realized, although some progress has been made. Here we report the electrical actuation and detection of the guitar-string-like oscillation modes of doubly clamped nanotube oscillators. We show that the resonance frequency can be widely tuned and that the devices can be used to transduce very small forces.

  18. Shear Flow Induced Alignment of Carbon Nanotubes in Natural Rubber

    Directory of Open Access Journals (Sweden)

    Yan He

    2015-01-01

    Full Text Available A new procedure for the fabrication of natural rubber composite with aligned carbon nanotubes is provided in this study. The two-step approach is based on (i the preparation of mixture latex of natural rubber, multiwalled carbon nanotubes, and other components and (ii the orientation of carbon nanotubes by a flow field. Rubber composite sheets filled with variable volume fraction of aligned carbon nanotubes were fabricated and then confirmed by transmission electron microscopy and Raman spectroscopy studies. An obvious increase in thermal conductivity has been obtained after the alignment of carbon nanotubes. The dynamic mechanical analysis was carried out in a tear mode for the composite.

  19. Carbon nanotubes as tips for atomic force microscopy

    Institute of Scientific and Technical Information of China (English)

    国立秋; 徐宗伟; 赵铁强; 赵清亮; 张飞虎; 董申

    2004-01-01

    Ordinary AFM probes' characters prevent the AFM' s application in various scopes. Carbon nanotubes represent ideal AFM probe materials for their higher aspect ratio, larger Young' s modulus, unique chemical structure, and well-defined electronic property. Carbon nanotube AFM probes are obtained by using a new method of attaching carbon nanotubes to the end of ordinary AFM probes, and are then used for doing AFM experiments. These experiments indicated that carbon nanotube probes have higher elastic deformation, higher resolution and higher durability. And it was also found that carbon nanotube probes can accurately reflect the morphology of deep narrow gaps, while ordinary probes can not reflect.

  20. Computational Nanomechanics of Carbon Nanotubes and Composites

    Science.gov (United States)

    Srivastava, Deepak; Wei, Chenyu; Cho, Kyeongjae; Biegel, Bryan (Technical Monitor)

    2002-01-01

    Nanomechanics of individual carbon and boron-nitride nanotubes and their application as reinforcing fibers in polymer composites has been reviewed with interplay of theoretical modeling, computer simulations and experimental observations. The emphasis in this work is on elucidating the multi-length scales of the problems involved, and of different simulation techniques that are needed to address specific characteristics of individual nanotubes and nanotube polymer-matrix interfaces. Classical molecular dynamics simulations are shown to be sufficient to describe the generic behavior such as strength and stiffness modulus but are inadequate to describe elastic limit and nature of plastic buckling at large strength. Quantum molecular dynamics simulations are shown to bring out explicit atomic nature dependent behavior of these nanoscale materials objects that are not accessible either via continuum mechanics based descriptions or through classical molecular dynamics based simulations. As examples, we discus local plastic collapse of carbon nanotubes under axial compression and anisotropic plastic buckling of boron-nitride nanotubes. Dependence of the yield strain on the strain rate is addressed through temperature dependent simulations, a transition-state-theory based model of the strain as a function of strain rate and simulation temperature is presented, and in all cases extensive comparisons are made with experimental observations. Mechanical properties of nanotube-polymer composite materials are simulated with diverse nanotube-polymer interface structures (with van der Waals interaction). The atomistic mechanisms of the interface toughening for optimal load transfer through recycling, high-thermal expansion and diffusion coefficient composite formation above glass transition temperature, and enhancement of Young's modulus on addition of nanotubes to polymer are discussed and compared with experimental observations.

  1. Boiling heat transfer correlations for refrigerant mixtures flowing inside micro-fin tubes

    Institute of Scientific and Technical Information of China (English)

    Xiaoyan ZHANG; Xingqun ZHANG; Yunguang CHEN; Xiuling YUAN

    2008-01-01

    Based on experimental results of ternary non-azeotropic refrigerant mixture R417A flowing and boiling in one smooth and two internally grooved horizontal tubes with different geometrical parameters, a boiling heat transfer correlations was developed for refrigerant mix-tures flowing inside micro-fin tubes by applying the enhancement factor in the present modified-Kattan model which was modified by the experimental data of R417A in a smooth tube. The comparison between the calculation and the experimental results indicates that the prediction by the present correlations is in good agreement with the experiment of refrigerant mixtures inside different micro-fin tubes with a standard deviation of ± 30% for vapor qualities below 80%.

  2. Nickel oxide nanotube synthesis using multiwalled carbon nanotubes as sacrificial templates for supercapacitor application

    Science.gov (United States)

    Abdalla, Ahmed M.; Sahu, Rakesh P.; Wallar, Cameron J.; Chen, Ri; Zhitomirsky, Igor; Puri, Ishwar K.

    2017-02-01

    A novel approach for the fabrication of nickel oxide nanotubes based on multiwalled carbon nanotubes as a sacrificial template is described. Electroless deposition is employed to deposit nickel onto carbon nanotubes. The subsequent annealing of the product in the presence of air oxidizes nickel to nickel oxide, and carbon is released as gaseous carbon dioxide, leaving behind nickel oxide nanotubes. Electron microscopy and elemental mapping confirm the formation of nickel oxide nanotubes. New chelating polyelectrolytes are used as dispersing agents to achieve high colloidal stability for both the nickel-coated carbon nanotubes and the nickel oxide nanotubes. A gravimetric specific capacitance of 245.3 F g-1 and an areal capacitance of 3.28 F cm-2 at a scan rate of 2 mV s-1 is achieved, with an electrode fabricated using nickel oxide nanotubes as the active element with a mass loading of 24.1 mg cm-2.

  3. Flexible microdevices based on carbon nanotubes

    Science.gov (United States)

    Allen, Ashante'; Cannon, Andrew; Lee, Jungchul; King, William P.; Graham, Samuel

    2006-12-01

    This work reports the fabrication and testing of flexible carbon nanotube microdevices made using hot embossing material transfer. Both micro-plasma and photodetector devices were made using as-grown unpurified multi-wall carbon nanotubes printed on PMMA substrates. Optical detectors were fabricated by attaching metal wires and monitoring the resistance as a function of light exposure. The electrical resistance of the nanotubes showed a strong sensitivity to light exposure which was also enhanced by heating the devices. While such processes in MWCNTs are not fully understood, the addition of thermal energy is believed to generate additional free charge carriers in the nanotubes. The plasma-generating microdevices consisted of a thin layer of thermoplastic polymer having the CNT electrode on one side and a metal electrode on the reverse side. The devices were electrically tested under atmospheric conditions with 0.01-1 kV ac and at 2.5 kHz, with the plasma igniting near 0.7 kV. The fabrication of these flexible organic devices demonstrates the ability to pattern useful carbon nanotube microdevices in low-cost thermoplastic polymers.

  4. Carbon nanotubes as optical biomedical sensors.

    Science.gov (United States)

    Kruss, Sebastian; Hilmer, Andrew J; Zhang, Jingqing; Reuel, Nigel F; Mu, Bin; Strano, Michael S

    2013-12-01

    Biosensors are important tools in biomedical research. Moreover, they are becoming an essential part of modern healthcare. In the future, biosensor development will become even more crucial due to the demand for personalized-medicine, point-of care devices and cheaper diagnostic tools. Substantial advances in sensor technology are often fueled by the advent of new materials. Therefore, nanomaterials have motivated a large body of research and such materials have been implemented into biosensor devices. Among these new materials carbon nanotubes (CNTs) are especially promising building blocks for biosensors due to their unique electronic and optical properties. Carbon nanotubes are rolled-up cylinders of carbon monolayers (graphene). They can be chemically modified in such a way that biologically relevant molecules can be detected with high sensitivity and selectivity. In this review article we will discuss how carbon nanotubes can be used to create biosensors. We review the latest advancements of optical carbon nanotube based biosensors with a special focus on near-infrared (NIR)-fluorescence, Raman-scattering and fluorescence quenching.

  5. Improved Method of Purifying Carbon Nanotubes

    Science.gov (United States)

    Delzeit, Lance D.

    2004-01-01

    An improved method of removing the residues of fabrication from carbon nanotubes has been invented. These residues comprise amorphous carbon and metal particles that are produced during the growth process. Prior methods of removing the residues include a variety of processes that involved the use of halogens, oxygen, or air in both thermal and plasma processes. Each of the prior methods entails one or more disadvantages, including non-selectivity (removal or damage of nanotubes in addition to removal of the residues), the need to dispose of toxic wastes, and/or processing times as long as 24 hours or more. In contrast, the process described here does not include the use of toxic chemicals, the generation of toxic wastes, causes little or no damage to the carbon nanotubes, and involves processing times of less than 1 hour. In the improved method, purification is accomplished by flowing water vapor through the reaction chamber at elevated temperatures and ambient pressures. The impurities are converted to gaseous waste products by the selective hydrogenation and hydroxylation by the water in a reaction chamber. This process could be performed either immediately after growth or in a post-growth purification process. The water used needs to be substantially free of oxygen and can be obtained by a repeated freeze-pump-thaw process. The presence of oxygen will non-selectively attach the carbon nanotubes in addition to the amorphous carbon.

  6. The cooling heat transfer characteristics of the supercritical CO2 in micro-fin tube

    Science.gov (United States)

    Lee, Ho-Saeng; Kim, Hyeon-Ju; Yoon, Jung-In; Choi, Kwang-Hwan; Son, Chang-Hyo

    2013-02-01

    This study intended to verify the cooling heat transfer characteristics of supercritical gas for refrigerating and air-conditioning devices that use CO2, a natural refrigerant, as the operating fluid. Experiments were performed with a gas cooler, which was the test part. The gas cooler was a heat exchanger made of a micro-fin tube with an inner diameter of 4.6 mm and an outer diameter of 5.0 mm. The experiment results are summarized as follows. The heat transfer coefficient, according to the mass flux, peaked at the low cooling pressure of 8.0 MPa in the gas cooler, and reached its minimum at the high pressure of 10.0 MPa. Furthermore, when the mass flux of the refrigerant increased, the coefficient increased faster with the lower cooling pressure in the gas cooler. The heat transfer coefficient, according to the shape of the heat transfer tube, showed that the maximum values of the CO2 cooling heat transfer coefficients of the smooth tube and the micro-fin tube were found at 44.7 °C, which were the pseudo-critical temperatures for the entrance pressures. It was found that the cooling heat transfer coefficient of the micro-fin tube increased by 12-39 % more than that of the smooth tube. The experiment results for the CO2 heat transfer coefficients of the smooth tube and the micro-fin tube were compared with the results estimated from previous correlations. It was found that the experiment values generally significantly differed from and the experiment values greater than the estimated values. The differences were especially greater in the vicinity of the critical temperature points. Based on these results, a new correlation was suggested that includes the density ratio and the specific heat ratio.

  7. Carbon Nanotube Membranes: Carbon Nanotube Membranes for Energy-Efficient Carbon Sequestration

    Energy Technology Data Exchange (ETDEWEB)

    None

    2010-03-01

    Broad Funding Opportunity Announcement Project: Porifera is developing carbon nanotube membranes that allow more efficient removal of CO2 from coal plant exhaust. Most of today’s carbon capture methods use chemical solvents, but capture methods that use membranes to draw CO2 out of exhaust gas are potentially more efficient and cost effective. Traditionally, membranes are limited by the rate at which they allow gas to flow through them and the amount of CO2 they can attract from the gas. Smooth support pores and the unique structure of Porifera’s carbon nanotube membranes allows them to be more permeable than other polymeric membranes, yet still selective enough for CO2 removal. This approach could overcome the barriers facing membrane-based approaches for capturing CO2 from coal plant exhausts.

  8. Structure Stability of Ⅰ-Type Carbon Nanotube Junctions

    Institute of Scientific and Technical Information of China (English)

    夏丹; 袁喆; 李家明

    2002-01-01

    Carbon nanotubes with junctions may play an important role in future ‘nanoelectronics' and future ‘nano devices'.In particular, junctions constructed with metal and semiconducting nanotubes have potential applications. Basedon the orthogonal tight-binding molecular dynamics method, we present our study of the structure stability ofI-type carbon nanotube junctions.

  9. Bioaccumulation and ecotoxicity of carbon nanotubes

    DEFF Research Database (Denmark)

    Jackson, Petra; Jacobsen, Nicklas Raun; Baun, Anders;

    2013-01-01

    Carbon nanotubes (CNT) have numerous industrial applications and may be released to the environment. In the aquatic environment, pristine or functionalized CNT have different dispersion behavior, potentially leading to different risks of exposure along the water column. Data included in this review...

  10. Effective models for excitons in carbon nanotubes

    DEFF Research Database (Denmark)

    Cornean, Horia; Duclos, Pierre; Ricaud, Benjamin

    2007-01-01

    We analyse the low lying spectrum of a model of excitons in carbon nanotubes. Consider two particles with opposite charges and a Coulomb self-interaction, placed on an infinitely long cylinder. If the cylinder radius becomes small, the low lying spectrum of their relative motion is well described...

  11. Effective models for excitons in carbon nanotubes

    DEFF Research Database (Denmark)

    Cornean, Horia; Duclos, Pierre; Ricaud, Benjamin

    We analyse the low lying spectrum of a model of excitons in carbon nanotubes. Consider two particles with a Coulomb self-interaction, placed on an infinitely long cylinder. If the cylinder radius becomes small, the low lying spectrum is well described by a one-dimensional effective Hamiltonian...

  12. In-line manufacture of carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Brambilla, Nicol Michele; Signorelli, Riccardo; Martini, Fabrizio; Corripio Luna, Oscar Enrique

    2015-04-28

    Mass production of carbon nanotubes (CNT) are facilitated by methods and apparatus disclosed herein. Advantageously, the methods and apparatus make use of a single production unit, and therefore provide for uninterrupted progress in a fabrication process. Embodiments of control systems for a variety of CNT production apparatus are included.

  13. Biodistribution of Carbon Nanotubes in Animal Models

    DEFF Research Database (Denmark)

    Jacobsen, Nicklas Raun; Møller, Peter; Clausen, Per Axel

    2016-01-01

    The many physical and chemical properties of carbon nanotubes (CNT) make it one of the most commercially attractive materials in the era of nanotechnology. Here, we review the recent publications on in vivo biodistribution of pristine and functionalized forms of single-walled and multi-walled CNT...

  14. Conductance of AFM Deformed Carbon Nanotubes

    Science.gov (United States)

    Svizhenko, Alexei; Maiti, Amitesh; Anatram, M. P.; Biegel, Bryan (Technical Monitor)

    2002-01-01

    This viewgraph presentation provides information on the electrical conductivity of carbon nanotubes upon deformation by atomic force microscopy (AFM). The density of states and conductance were computed using four orbital tight-binding method with various parameterizations. Different chiralities develop bandgap that varies with chirality.

  15. Multiwall carbon nanotubes reinforced epoxy nanocomposites

    Science.gov (United States)

    Chen, Wei

    The emergence of carbon nanotubes (CNTs) has led to myriad possibilities for structural polymer composites with superior specific modulus, strength, and toughness. While the research activities in carbon nanotube reinforced polymer composites (NRPs) have made enormous progress towards fabricating next-generation advanced structural materials with added thermal, optical, and electrical advantages, questions concerning the filler dispersion, interface, and CNT alignment in these composites remain partially addressed. In this dissertation, the key technical challenges related to the synthesis, processing, and reinforcing mechanics governing the effective mechanical properties of NRPs were introduced and reviewed in the first two chapters. Subsequently, issues on the dispersion, interface control, hierarchical structure, and multi-functionality of NRPs were addressed based on functionalized multi-walled carbon nanotube reinforced DGEBA epoxy systems (NREs). In chapter 3, NREs with enhanced flexural properties were discussed in the context of improved dispersion and in-situ formation of covalent bonds at the interface. In chapter 4, NREs with controlled interface and tailored thermomechanical properties were demonstrated through the judicious choice of surface functionality and resin chemistry. In chapter 5, processing-condition-induced CNT organization in hierarchical epoxy nanocomposites was analyzed. In Chapter 6, possibilities were explored for multi-functional NREs for underwater acoustic structural applications. Finally, the findings of this dissertation were concluded and future research was proposed for ordered carbon nanotube array reinforced nanocomposites in the last chapter. Four journal publications resulted from this work are listed in Appendix.

  16. Spatially resolved spectroscopy on carbon nanotubes

    NARCIS (Netherlands)

    Janssen, J.W.

    2001-01-01

    Carbon nanotubes are small cylindrical molecules with a typical diameter of 1 nm and lengths of up to micrometers. These intriguing molecules exhibit, depending on the exact atomic structure, either semiconducting or metallic behavior. This makes them ideal candidates for possible future molecular e

  17. Chemistry of Carbon Nanotubes for Everyone

    Science.gov (United States)

    Basu-Dutt, Sharmistha; Minus, Marilyn L.; Jain, Rahul; Nepal, Dhriti; Kumar, Satish

    2012-01-01

    Carbon nanotubes (CNTs) have the extraordinary potential to change our lives by improving existing products and enabling new ones. Current and future research and industrial workforce professionals are very likely to encounter some aspects of nanotechnology including CNT science and technology in their education or profession. The simple structure…

  18. Single electron-ics with carbon nanotubes

    NARCIS (Netherlands)

    Götz, G.T.J.

    2010-01-01

    We experimentally investigate Quantum Dots, formed in Carbon Nanotubes. The first part of this thesis deals with charge sensing on such quantum dots. The charge sensor is a metallic Single-electron-transistor, sensitive to the charge of a single electron on the quantum dot. We use this technique for

  19. Photothermal effects of immunologically modified carbon nanotubes

    Science.gov (United States)

    Griswold, Ryan T.; Henderson, Brock; Goddard, Jessica; Tan, Yongqiang; Hode, Tomas; Liu, Hong; Nordquist, Robert E.; Chen, Wei R.

    2013-02-01

    Carbon nanotubes have a great potential in the biomedical applications. To use carbon nanotubes in the treatment of cancer, we synthesized an immunologically modified single-walled carbon nanotube (SWNT) using a novel immunomodifier, glycated chitosan (GC), as an effective surfactant for SWNT. This new composition SWNT-GC was stable due to the strong non-covalent binding between SWNT and GC. The structure of SWNT-GC is presented in this report. The photothermal effect of SWNT-GC was investigated under irradiation of a near-infrared laser. SWNT-GC retained the optical properties of SWNT and the immunological properties of GC. Specifically, the SWNT-GC could selectively absorb a 980-nm light and induce desirable thermal effects in tissue culture and in animals. It could also induce tumor cell destruction, controlled by the laser settings and the doses of SWNT and GC. Laser+SWNT-GC treatment could also induce strong expression of heat shock proteins on the surface of tumor cells. This immunologically modified carbon nanotube could be used for selective photothermal interactions in noninvasive tumor treatment.

  20. Synthesis of Carbon Nanotube (CNT Composite Membranes

    Directory of Open Access Journals (Sweden)

    Dusan Losic

    2010-12-01

    Full Text Available Carbon nanotubes are attractive approach for designing of new membranes for advanced molecular separation because of their unique transport properties and ability to mimic biological protein channels. In this work the synthetic approach for fabrication of carbon nanotubes (CNTs composite membranes is presented. The method is based on growth of multi walled carbon nanotubes (MWCNT using chemical vapour deposition (CVD on the template of nanoporous alumina (PA membranes. The influence of experimental conditions including carbon precursor, temperature, deposition time, and PA template on CNT growth process and quality of fabricated membranes was investigated. The synthesis of CNT/PA composites with controllable nanotube dimensions such as diameters (30–150 nm, and thickness (5–100 µm, was demonstrated. The chemical composition and morphological characteristics of fabricated CNT/PA composite membranes were investigated by various characterisation techniques including scanning electron microscopy (SEM, energy-dispersive x-ray spectroscopy (EDXS, high resolution transmission electron microscopy (HRTEM and x-ray diffraction (XRD. Transport properties of prepared membranes were explored by diffusion of dye (Rose Bengal used as model of hydrophilic transport molecule.

  1. A New Resistance Formulation for Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Ji-Huan He

    2008-01-01

    Full Text Available A new resistance formulation for carbon nanotubes is suggested using fractal approach. The new formulation is also valid for other nonmetal conductors including nerve fibers, conductive polymers, and molecular wires. Our theoretical prediction agrees well with experimental observation.

  2. A new mechanism for carbon nanotube evolution

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ Key discoveries on the growth mechanism of carbon nanotubes(CNTs) have recently been achieved by CAS researcher ZHU Zhenping and his research group at the State Key Laboratory of Coal Conversion,the Institute of Coal Chemistry of CAS, funded by the National Natural Science Foundation of China and the CAS Bairen Program.

  3. Quantum transport in carbon nanotubes

    DEFF Research Database (Denmark)

    Laird, Edward A.; Kuemmeth, Ferdinand; Steele, Gary A.

    2015-01-01

    modifies their transport behaviour. Interaction between electrons inside and outside a quantum dot is manifested in SU(4) Kondo behavior and level renormalization. Interaction within a dot leads to Wigner molecules and more complex correlated states. This review takes an experimental perspective informed...... and valley degrees of freedom. This review describes the modern understanding of transport through nanotube devices. Unlike conventional semiconductors, electrons in nanotubes have two angular momentum quantum numbers, arising from spin and from valley freedom. We focus on the interplay between the two....... In single quantum dots defined in short lengths of nanotube, the energy levels associated with each degree of freedom, and the spin-orbit coupling between them, are revealed by Coulomb blockade spectroscopy. In double quantum dots, the combination of quantum numbers modifies the selection rules of Pauli...

  4. Making junctions between carbon nanotubes using an ion beam

    CERN Document Server

    Krasheninnikov, A V; Keinonen, J; Banhart, F

    2003-01-01

    Making use of empirical potential molecular dynamics, we study ion bombardment of crossed single-walled carbon nanotubes as a tool to join the nanotubes. We demonstrate that ion irradiation should result in welding of crossed nanotubes, both suspended and deposited on substrates. We further predict optimum ion doses and energies for ion-mediated nanotube welding which may potentially be used for developing complicated networks of joined nanotubes.

  5. Carbon nanotubes for stem cell control

    Directory of Open Access Journals (Sweden)

    David A. Stout

    2012-07-01

    Full Text Available In the past decade, two major advancements have transformed the world of tissue engineering and regenerative medicine—stem cells and carbon nano-dimensional materials. In the past, stem cell therapy seemed like it may present a cure for all medical ailments, but problems arose (i.e., immune system clearance, control of differentiation in the body, etc. that have hindered progress. But, with the synergy of carbon nano-dimensional materials, researchers have been able to overcome these tissue engineering and regenerative medicine obstacles and have begun developing treatments for strokes, bone failure, cardiovascular disease, and many other conditions. Here, we briefly review research involving carbon nanotubes which are relevant to the tissue engineering and regenerative medicine field with a special emphasis on carbon nanotube applications for stem cell delivery, drug delivery applications, and their use as improved medical devices.

  6. Aluminum-based one- and two-dimensional micro fin array structures: high-throughput fabrication and heat transfer testing

    Science.gov (United States)

    Primeaux, Philip A.; Zhang, Bin; Zhang, Xiaoman; Miller, Jacob; Meng, W. J.; KC, Pratik; Moore, Arden L.

    2017-02-01

    Microscale fin array structures were replicated onto surfaces of aluminum 1100 and aluminum 6061 alloy (Al1100/Al6061) sheet metals through room-temperature instrumented roll molding. Aluminum-based micro fin arrays were replicated at room temperature, and the fabrication process is one with high throughput and low cost. One-dimensional (1D) micro fin arrays were made through one-pass rolling, while two-dimensional (2D) micro fin arrays were made by sequential 90° cross rolling with the same roller sleeve. For roll molding of 1D micro fins, fin heights greater than 600 µm were achieved and were shown to be proportional to the normal load force per feature width. At a given normal load force, the fin height was further shown to scale inversely with the hardness of the sheet metal. For sequential 90° cross rolling, morphologies of roll molded 2D micro fin arrays were examined, which provided clues to understand how plastic deformation occurred under cross rolling conditions. A series of pool boiling experiments on low profile Al micro fin array structures were performed within Novec 7100, a widely used commercial dielectric coolant. Results for both horizontal and vertical surface orientations show that roll molded Al micro fin arrays can increase heat flux at fixed surface temperature as compared to un-patterned Al sheet. The present results further suggest that many factors beyond just increased surface area can influence heat transfer performance, including surface finish and the important multiphase transport mechanisms in and around the fin geometry. These factors must also be considered when designing and optimizing micro fin array structures for heat transfer applications.

  7. Convective Boiling of Near-Azeotropic Refrigerant R410A in the Horizontal Micro-fin Tube

    Institute of Scientific and Technical Information of China (English)

    DUAN Xue-tao; MA Hu-gen; WU Zhi-min; WANG Fang

    2007-01-01

    Using near-azeotropic refrigerant R410A as the working fluid, the experimental studies on the horizontal micro-fin tubes were conducted. Several factors affecting heat transfer coefficients were analyzed, and the characteristics of flow boiling of the refrigerant in the horizontal micro-fin tubes were discussed. The local heat transfer coefficients increase with mass flux, heat flux and quality. And the heat transfer enhancement factor of those testing tubes is about 1.6 to 2.2.

  8. Pure carbon nanoscale devices: Nanotube heterojunctions

    Energy Technology Data Exchange (ETDEWEB)

    Chico, L.; Crespi, V.H.; Benedict, L.X.; Louie, S.G.; Cohen, M.L. [Department of Physics, University of California at Berkeley, Berkeley, California 94720 (United States)]|[Materials Sciences Division, Lawrence Berkeley Laboratory, Berkeley, California 94720 (United States)

    1996-02-01

    Introduction of pentagon-heptagon pair defects into the hexagonal network of a single carbon nanotube can change the helicity of the tube and alter its electronic structure. Using a tight-binding method to calculate the electronic structure of such systems we show that they behave as nanoscale metal/semiconductor or semiconductor/semiconductor junctions. These junctions could be the building blocks of nanoscale electronic devices made entirely of carbon. {copyright} {ital 1996 The American Physical Society.}

  9. Exploring the Immunotoxicity of Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Yu Yanmei

    2008-01-01

    Full Text Available Abstract Mass production of carbon nanotubes (CNTs and their applications in nanomedicine lead to the increased exposure risk of nanomaterials to human beings. Although reports on toxicity of nanomaterials are rapidly growing, there is still a lack of knowledge on the potential toxicity of such materials to immune systems. This article reviews some existing studies assessing carbon nanotubes’ toxicity to immune system and provides the potential mechanistic explanation.

  10. Preparation of double-walled carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    JIANG Bin; WEI Jinquan; CI Lijie; WU Dehai

    2004-01-01

    Double-walled carbon nanotubes were prepared using the floating chemical vapor deposition with methane as carbon source and adding small amount of sulfur into the ferrocene catalyst. The optimized technological parameters are: the reaction temperature is 1200℃; the catalyst vapor temperature is 80℃; the flow rate of argon is 2000 SCCM; the flow rate of methane is 5 SCCM. The purified DWNTs under these optimized technological parameters have high purity above 90 wt%.

  11. Synthesis, characterisation and applications of coiled carbon nanotubes.

    Science.gov (United States)

    Hanus, Monica J; Harris, Andrew T

    2010-04-01

    Coiled carbon nanotubes are helical carbon structures formed when heptagonal and pentagonal rings are inserted into the hexagonal backbone of a 'straight' nanotube. Coiled carbon nanotubes have been reported with both regular and irregular helical structures. In this work the structure, growth mechanism(s), synthesis, properties and potential applications of coiled carbon nanotubes are reviewed. Published data suggests that coiled carbon nanotube synthesis occurs due to nonuniform extrusion of carbon from a catalyst surface. To date, coiled carbon nanotubes have been synthesised using catalyst modification techniques including: (i) the addition of S or P containing compounds during synthesis; (ii) the use of binary or ternary metal catalysts; (iii) the use of microwaves to create a local temperature gradient around individual catalyst particles and; (iv) the use of pH control during catalyst preparation. In most instances coiled carbon nanotubes are produced as a by-product; high yield and/or large-scale synthesis of coiled carbon nanotubes remains problematic. The qualitative analysis of coiled carbon nanotubes is currently hindered by the absence of specific characterisation data in the literature, e.g., oxidation profiles measured by thermogravimetric analysis and Raman spectra of pure coiled carbon nanotube samples.

  12. Carbon nanotube oscillators for applications as nanothermometers

    Science.gov (United States)

    Rahmat, Fainida; Thamwattana, Ngamta; Hill, James M.

    2010-10-01

    Nanostructures such as carbon nanotubes have a broad range of potential applications such as nanomotors, nano-oscillators and electromechanical nanothermometers, and a proper understanding of the molecular interaction between nanostructures is fundamentally important for these applications. In this paper, we determine the molecular interaction potential of interacting carbon nanotubes for two configurations. The first is a shuttle configuration involving a short outer tube sliding on a fixed inner tube, and the second involves a telescopic configuration for which an inner tube moves both in the region between two outer tubes and through the tubes themselves. For the first configuration we examine two cases of semi-infinite and finite inner carbon nanotubes. We employ the continuum approximation and the 6-12 Lennard-Jones potential for non-bonded molecules to determine the molecular interaction potential and the resulting van der Waals force, and we evaluate the resulting surface integrals numerically. We also investigate the acceptance condition and suction energy for the first configuration. Our results show that for the shuttle configuration with a semi-infinite inner tube, the suction energy is maximum when the difference between the outer and inner tubes radii is approximately 3.4 Å, which is the ideal inter-wall spacing between graphene sheets. For the finite inner tube, the potential energy is dependent on both the inner and outer tube lengths as well as on the inter-wall spacing. In terms of the oscillating frequency, the critical issue is the length of the moving outer tube, and the shorter the length, the higher the frequency. Further, for the telescopic configuration with two semi-infinite outer nanotubes of different radii, we find that the interaction energy also depends on the difference of the tube radii. For two outer nanotubes of equal radii we observe that the shorter the distance between the two outer nanotubes, the higher the magnitude of the

  13. Field-effect transistors assembled from functionalized carbon nanotubes

    OpenAIRE

    Klinke, Christian; Hannon, James B.; Afzali, Ali; Avouris, Phaedon

    2006-01-01

    We have fabricated field effect transistors from carbon nanotubes using a novel selective placement scheme. We use carbon nanotubes that are covalently bound to molecules containing hydroxamic acid functionality. The functionalized nanotubes bind strongly to basic metal oxide surfaces, but not to silicon dioxide. Upon annealing, the functionalization is removed, restoring the electronic properties of the nanotubes. The devices we have fabricated show excellent electrical characteristics.

  14. Porous carbon nanotubes: Molecular absorption, transport, and separation

    Science.gov (United States)

    Yzeiri, Irena; Patra, Niladri; Král, Petr

    2014-03-01

    We use classical molecular dynamics simulations to study nanofluidic properties of porous carbon nanotubes. We show that saturated water vapor condenses on the porous nanotubes, can be absorbed by them and transported in their interior. When these nanotubes are charged and placed in ionic solutions, they can selectively absorb ions in their interior and transport them. Porous carbon nanotubes can also be used as selective molecular sieves, as illustrated on a room temperature separation of benzene and ethanol.

  15. Carbon nanotubes on a spider silk scaffold

    Science.gov (United States)

    Steven, Eden; Saleh, Wasan R.; Lebedev, Victor; Acquah, Steve F. A.; Laukhin, Vladimir; Alamo, Rufina G.; Brooks, James S.

    2013-09-01

    Understanding the compatibility between spider silk and conducting materials is essential to advance the use of spider silk in electronic applications. Spider silk is tough, but becomes soft when exposed to water. Here we report a strong affinity of amine-functionalised multi-walled carbon nanotubes for spider silk, with coating assisted by a water and mechanical shear method. The nanotubes adhere uniformly and bond to the silk fibre surface to produce tough, custom-shaped, flexible and electrically conducting fibres after drying and contraction. The conductivity of coated silk fibres is reversibly sensitive to strain and humidity, leading to proof-of-concept sensor and actuator demonstrations.

  16. Localization in single-walled carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Fuhrer, M.S.; Cohen, M.L.; Zettl, A.; Crespi, V.H.

    1998-08-15

    We demonstrate that in low temperature semiconductor-like regions the electrical resistance of single-walled carbon nanotube mats is highly nonlinear with a temperature-dependent threshold field for the onset of nonohmic conduction. The modest applied electric field completely suppresses the upturn in resistance and recovers metallic behavior over the entire temperature range 2.2K < T < 300K. The transport data indicate low-temperature localization of charge carriers arise from disorder on the nanotube bundles themselves and not from granularity caused by weak interbundle connections. The temperature-independent localization radius a is determined to be approximately 330 nm.

  17. Heat transfer characteristics in micro-fin tube equipped with double twisted tapes: Effect of twisted tape and micro-fin tube arrangements

    Institute of Scientific and Technical Information of China (English)

    EIAMSA-ARD S.; WONGCHAREE K.

    2013-01-01

    An experimental study was carried out to investigate the influence of double twisted-tape inserts (DTs) in micro-fin tubes (MFs) on heat transfer,friction factor and thermal performance factor characteristics of the compound devices in the following configurations:(1) twisted tapes acted in the same direction (for co-swirl) while MF and twisted tapes acted in the same (parallel) direction (MF-CoDTs:P),(2) twisted tapes acted in the same direction (for co-swirl) while micro-fin tube and twisted tapes acted in opposite directions (MF-CoDTs:O) and (3) twisted tapes acted in opposite directions for counter swirl (MF-CDTs).The MF alone and the MF equipped with a single twisted tape in parallel/opposite arrangement were also considered for comparison.The experiments were conducted for the flows with the Reynolds numbers between 5 650 and 17 000,under uniform heat flux condition.The experimental results indicate that MF-CDTs induce stronger swirl/turbulence flow,resulting in higher heat transfer rate,friction factor and thermal performance factor than other combined devices.The thermal performance factors associated with the use of MF-CDTs were found to be higher than those associated with the uses of MF-CoDTs:P,MF-CoDTs:O and MF alone up to 9.3%,6.5% and 56.4%,respectively.The empirical correlations developed using the present experimental data for the Nusselt number,friction factor and thermal performance factor are also reported.

  18. A new method of preparing single-walled carbon nanotubes

    OpenAIRE

    Vivekchang, SRC; Govindaraj, A.

    2003-01-01

    A novel method of purification for single-walled carbon nanotubes, prepared by an arc-discharge method, is described. The method involves a combination of acid washing followed by high temperature hydrogen treatment to remove the metal nanoparticles and amorphous carbon present in the as-synthesized single-walled carbon nanotubes. The purified single-walled carbon nanotubes have been characterised by low-angle X-ray diffraction, electron microscopy, thermo-gravimetric analysis and Raman spect...

  19. Carbon Nanotubes Hybrid Hydrogels in Drug Delivery: A Perspective Review

    OpenAIRE

    Giuseppe Cirillo; Silke Hampel; Umile Gianfranco Spizzirri; Ortensia Ilaria Parisi; Nevio Picci; Francesca Iemma

    2014-01-01

    The use of biologics, polymers, silicon materials, carbon materials, and metals has been proposed for the preparation of innovative drug delivery devices. One of the most promising materials in this field are the carbon-nanotubes composites and hybrid materials coupling the advantages of polymers (biocompatibility and biodegradability) with those of carbon nanotubes (cellular uptake, stability, electromagnatic, and magnetic behavior). The applicability of polymer-carbon nanotubes composites i...

  20. A new method of preparing single-walled carbon nanotubes

    Indian Academy of Sciences (India)

    S R C Vivekchand; A Govindaraj

    2003-10-01

    A novel method of purification for single-walled carbon nanotubes, prepared by an arc-discharge method, is described. The method involves a combination of acid washing followed by high temperature hydrogen treatment to remove the metal nanoparticles and amorphous carbon present in the as-synthesized singlewalled carbon nanotubes. The purified single-walled carbon nanotubes have been characterised by low-angle X-ray diffraction, electron microscopy, thermo-gravimetric analysis and Raman spectroscopy.

  1. Thin Coatings of Polymeric Carbon and Carbon Nanotubes for Corrosion Protection

    Science.gov (United States)

    2009-02-01

    Carbon Nanotube Functionalization /Doping Polyvinylpyrrolidone (PVP) A) p-Doping C) Polymer Wrapping Model B) n-Doping Polyethyleneimine ( PEI ) SWCNT Paint...fluorine-containing) groups functions as the barrier layer Multilayer Smart Carbon Nanotube Coating Insoluble polymer layer top coating -PMMA Substrate...Thin Coatings of Polymeric Carbon and Carbon Nanotubes for Corrosion Protection Zafar Iqbal Department of Chemistry and Environmental Science New

  2. Functionalization of vertically aligned carbon nanotubes

    Directory of Open Access Journals (Sweden)

    Eloise Van Hooijdonk

    2013-02-01

    Full Text Available This review focuses and summarizes recent studies on the functionalization of carbon nanotubes oriented perpendicularly to their substrate, so-called vertically aligned carbon nanotubes (VA-CNTs. The intrinsic properties of individual nanotubes make the VA-CNTs ideal candidates for integration in a wide range of devices, and many potential applications have been envisaged. These applications can benefit from the unidirectional alignment of the nanotubes, the large surface area, the high carbon purity, the outstanding electrical conductivity, and the uniformly long length. However, practical uses of VA-CNTs are limited by their surface characteristics, which must be often modified in order to meet the specificity of each particular application. The proposed approaches are based on the chemical modifications of the surface by functionalization (grafting of functional chemical groups, decoration with metal particles or wrapping of polymers to bring new properties or to improve the interactions between the VA-CNTs and their environment while maintaining the alignment of CNTs.

  3. Carbon nanotubes degraded by neutrophil myeloperoxidase induce less pulmonary inflammation

    Science.gov (United States)

    Kagan, Valerian E.; Konduru, Nagarjun V.; Feng, Weihong; Allen, Brett L.; Conroy, Jennifer; Volkov, Yuri; Vlasova, Irina I.; Belikova, Natalia A.; Yanamala, Naveena; Kapralov, Alexander; Tyurina, Yulia Y.; Shi, Jingwen; Kisin, Elena R.; Murray, Ashley R.; Franks, Jonathan; Stolz, Donna; Gou, Pingping; Klein-Seetharaman, Judith; Fadeel, Bengt; Star, Alexander; Shvedova, Anna A.

    2010-05-01

    We have shown previously that single-walled carbon nanotubes can be catalytically biodegraded over several weeks by the plant-derived enzyme, horseradish peroxidase. However, whether peroxidase intermediates generated inside human cells or biofluids are involved in the biodegradation of carbon nanotubes has not been explored. Here, we show that hypochlorite and reactive radical intermediates of the human neutrophil enzyme myeloperoxidase catalyse the biodegradation of single-walled carbon nanotubes in vitro, in neutrophils and to a lesser degree in macrophages. Molecular modelling suggests that interactions of basic amino acids of the enzyme with the carboxyls on the carbon nanotubes position the nanotubes near the catalytic site. Importantly, the biodegraded nanotubes do not generate an inflammatory response when aspirated into the lungs of mice. Our findings suggest that the extent to which carbon nanotubes are biodegraded may be a major determinant of the scale and severity of the associated inflammatory responses in exposed individuals.

  4. Adsorption of Gases on Carbon Nanotubes

    Science.gov (United States)

    Mbaye, Mamadou Thiao

    2014-01-01

    This research focus in studying the interaction between various classical and quantum gases with novel carbon nanostructures, mainly carbon nanotubes (CNTs). Since their discovery by the Japanese physicist Sumio Iijima [1] carbon nanotubes have, experimentally and theoretically, been subjected to many scientific investigation. Studies of adsorption on CNTs are particularly directed toward their better usage in gas storage, gas separation, catalyst, drug delivery, and water purification. We explore the adsorption of different gases entrapped in a single, double, or multi-bundles of CNTs using computer simulations. The first system we investigate consists of Ar and Kr films adsorbed on zigzag or armchair nanotubes. Our simulations revealed that Kr atoms on intermediate size zigzag NTs undergo two phase transitions: A liquid-vapor (L→V), and liquid-commensurate (L→CS) with a fractional coverage of one Kr atoms adsorbed for every four carbon atoms. For Ar on zigzag and armchair NTs, the only transition observed is a L→V. In the second problem, we explore the adsorption of CO2 molecules in a nanotube bundle and calculate the isosteric heat of adsorption of the entrapped molecules within the groove. We observed that the lower the temperature, the higher the isosteric of adsorption. Last, we investigate the adsorption of hydrogen, Helium, and Neon gases on the groove site of two parallel nanotubes. At low temperature, the transverse motion on the plane perpendicular to the tubes' axis is frozen out and as a consequence, the heat capacity is reduced to 1/2. At high temperature, the atoms gain more degree of freedom and as a consequence the heat capacity is 5/2.

  5. Purification of Carbon Nanotubes by Proton Irradiation

    Science.gov (United States)

    Kim, Euikwoun; Lee, Jeonggil; Lee, Younman; Jeon, Jaekyun; Kim, Jae-Yong; Kim, Jeongha; Shin, Kwanwoo; Youn, Sang-Pil; Kim, Kyeryung

    2007-10-01

    Carbon nanotubes (CNTs) exhibit variety of superior physical properties including well-defined nanodimensional structure, high electrical and thermal conductivity, and good mechanical stability against external irradiations. Further, a large specific surface area per unit weight suggests that carbon nanotubes could be excellent candidates for gas storage, purification, and separation. However, the practical application of CNTs is limited mainly due to the metallic impurities that were used as a catalyst during the fabrication process. Here, we irradiated CNTs by using high energy proton beams (35.7 MeV at the Bragg Peak). Interestingly, metallic impurities such as Fe, Ni, Co and chunk of amorphous carbon that were attached on the surface of CNTs were completely removed after the irradiation. The mechanism of such the purification process is not understood. The possible speculation will be demonstrated combined with the changes of physical properties including the appearance of the magnetism after the irradiation.

  6. Mechanical properties of functionalized carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Z Q; Liu, B; Chen, Y L; Hwang, K C [FML, Department of Engineering Mechanics, Tsinghua University, Beijing 100084 (China); Jiang, H [Department of Mechanical and Aerospace Engineering, Arizona State University, Tempe, AZ 85287 (United States); Huang, Y [Department of Civil and Environmental Engineering, Northwestern University, Evanston, IL 60208 (United States)], E-mail: liubin@tsinghua.edu.cn, E-mail: y-huang@northwestern.edu

    2008-10-01

    Carbon nanotubes (CNTs) used to reinforce polymer matrix composites are functionalized to form covalent bonds with the polymer in order to enhance the CNT/polymer interfaces. These bonds destroy the perfect atomic structures of a CNT and degrade its mechanical properties. We use atomistic simulations to study the effect of hydrogenization on the mechanical properties of single-wall carbon nanotubes. The elastic modulus of CNTs gradually decreases with the increasing functionalization (percentage of C-H bonds). However, both the strength and ductility drop sharply at a small percentage of functionalization, reflecting their sensitivity to C-H bonds. The cluster C-H bonds forming two rings leads to a significant reduction in the strength and ductility. The effect of carbonization has essentially the same effect as hydrogenization.

  7. On the Nanoindentation of the Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Petre P. Teodorescu

    2010-01-01

    Full Text Available A new inverse approach is proposed in this paper, which combines elements of nonlocal theory and molecular mechanics, based on the experimental results available in the nanoindentation literature. The effect of the inlayer van der Waals atomistic interactions for carbon nanotubes with multiple walls (MWCNT is included by means of the Brenner-Tersoff potential and experimental results. The neighboring walls of MWCNT are coupled through van der Waals interactions, and the shell buckling would initiate in the outermost shell, when nanotubes are short. The nanoindentation technique is simulated for the axially compressed of individual nanotubes, in order to evaluate the load-unloaded-displacement, the curve critical buckling and the appropriate values for local Lamé constants.

  8. Carbon nanotube materials from hydrogen storage

    Energy Technology Data Exchange (ETDEWEB)

    Dillon, A.C.; Bekkedahl, T.A.; Cahill, A.F. [National Renewable Energy Laboratory, Golden, CO (United States)

    1995-09-01

    The lack of convenient and cost-effective hydrogen storage is a major impediment to wide scale use of hydrogen in the United States energy economy. Improvements in the energy densities of hydrogen storage systems, reductions in cost, and increased compatibility with available and forecasted systems are required before viable hydrogen energy use pathways can be established. Carbon-based hydrogen adsorption materials hold particular promise for meeting and exceeding the U.S. Department of Energy hydrogen storage energy density targets for transportation if concurrent increases in hydrogen storage capacity and carbon density can be achieved. These two goals are normally in conflict for conventional porous materials, but may be reconciled by the design and synthesis of new adsorbent materials with tailored pore size distributions and minimal macroporosity. Carbon nanotubes offer the possibility to explore new designs for adsorbents because they can be fabricated with small size distributions, and naturally tend to self-assemble by van der Waals forces. This year we report heats of adsorption for hydrogen on nanotube materials that are 2 and 3 times greater than for hydrogen on activated carbon. The hydrogen which is most strongly bound to these materials remains on the carbon surface to temperatures greater than 285 K. These results suggest that nanocapillary forces are active in stabilizing hydrogen on the surfaces of carbon nanotubes, and that optimization of the adsorbent will lead to effective storage at higher temperatures. In this paper we will also report on our activities which are targeted at understanding and optimizing the nucleation and growth of single wall nanotubes. These experiments were made possible by the development of a unique feedback control circuit which stabilized the plasma-arc during a synthesis run.

  9. Carbon Nanotubes for Space Photovoltaic Applications

    Science.gov (United States)

    Efstathiadis, Harry; Haldar, Pradeep; Landi, Brian J.; Denno, Patrick L.; DiLeo, Roberta A.; VanDerveer, William; Raffaelle, Ryne P.

    2007-01-01

    Carbon nanotubes (CNTs) can be envisioned as an individual graphene sheet rolled into a seamless cylinder (single-walled, SWNT), or concentric sheets as in the case of a multi-walled carbon nanotube (MWNT) (1). The role-up vector will determine the hexagonal arrangement and "chirality" of the graphene sheet, which will establish the nanotube to be metallic or semiconducting. The optoelectronic properties will depend directly on this chiral angle and the diameter of the SWNT, with semiconductor types exhibiting a band gap energy (2). Characteristic of MWNTs are the concentric graphene layers spaced 0.34 nm apart, with diameters from 10-200 nm and lengths up to hundreds of microns (2). In the case of SWNTs, the diameters range from 0.4 - 2 nm and lengths have been reported up to 1.5 cm (3). SWNTs have the distinguishable property of "bundling" together due to van der Waal's attractions to form "ropes." A comparison of these different structural types is shown in Figure 1. The use of SWNTS in space photovoltaic (PV) applications is attractive for a variety of reasons. Carbon nanotubes as a class of materials exhibit unprecedented optical, electrical, mechanical properties, with the added benefit of being nanoscale in size which fosters ideal interaction in nanomaterial-based devices like polymeric solar cells. The optical bandgap of semiconducting SWNTs can be varied from approx. 0.4 - 1.5 eV, with this property being inversely proportional to the nanotube diameter. Recent work at GE Global Research has shown where a single nanotube device can behave as an "ideal" pn diode (5). The SWNT was bridged over a SiO2 channel between Mo contacts and exhibited an ideality factor of 1, based on a fit of the current-voltage data using the diode equation. The measured PV efficiency under a 0.8 eV monochromatic illumination showed a power conversion efficiency of 0.2 %. However, the projected efficiency of these junctions is estimated to be > 5 %, especially when one considers the

  10. Carbon Micronymphaea: Graphene on Vertically Aligned Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Jong Won Choi

    2013-01-01

    Full Text Available This paper describes the morphology of carbon nanomaterials such as carbon nanotube (CNT, graphene, and their hybrid structure under various operating conditions during a one-step synthesis via plasma-enhanced chemical vapor deposition (PECVD. We focus on the synthetic aspects of carbon hybrid material composed of heteroepitaxially grown graphene on top of a vertical array of carbon nanotubes, called carbon micronymphaea. We characterize the structural features of this unique nanocomposite by uses of electron microscopy and micro-Raman spectroscopy. We observe carbon nanofibers, poorly aligned and well-aligned vertical arrays of CNT sequentially as the growth temperature increases, while we always discover the carbon hybrids, called carbon micronymphaea, at specific cooling rate of 15°C/s, which is optimal for the carbon precipitation from the Ni nanoparticles in this study. We expect one-pot synthesized graphene-on-nanotube hybrid structure poses great potential for applications that demand ultrahigh surface-to-volume ratios with intact graphitic nature and directional electronic and thermal transports.

  11. Multifunctional Carbon Nanotube Fiber Composites

    Science.gov (United States)

    2007-11-02

    coagulant. The second process (patent pending) is novel in that it directly results polymer-free nanotube fibers without using a super acid spinning...chemical and electrochemical stability, hydrophobicity and viscosity . The generic structure, chemical name and abbreviations for the most common ions...modification procedure involved the electrochemical infiltration of small amounts of the polypyrrole/p-toluene sulphonate (PPy/PTS) conducting polymer

  12. Use of Functionalized Carbon Nanotubes for Covalent Attachment of Nanotubes to Silicon

    Science.gov (United States)

    Tour, James M.; Dyke, Christopher A.; Maya, Francisco; Stewart, Michael P.; Chen, Bo; Flatt, Austen K.

    2012-01-01

    The purpose of the invention is to covalently attach functionalized carbon nanotubes to silicon. This step allows for the introduction of carbon nanotubes onto all manner of silicon surfaces, and thereby introduction of carbon nano - tubes covalently into silicon-based devices, onto silicon particles, and onto silicon surfaces. Single-walled carbon nanotubes (SWNTs) dispersed as individuals in surfactant were functionalized. The nano - tube was first treated with 4-t-butylbenzenediazonium tetrafluoroborate to give increased solubility to the carbon nanotube; the second group attached to the sidewall of the nanotube has a silyl-protected terminal alkyne that is de-protected in situ. This gives a soluble carbon nanotube that has functional groups appended to the sidewall that can be attached covalently to silicon. This reaction was monitored by UV/vis/NJR to assure direct covalent functionalization.

  13. Metal-enhanced fluorescence of carbon nanotubes.

    Science.gov (United States)

    Hong, Guosong; Tabakman, Scott M; Welsher, Kevin; Wang, Hailiang; Wang, Xinran; Dai, Hongjie

    2010-11-17

    The photoluminescence (PL) quantum yield of single-walled carbon nanotubes (SWNTs) is relatively low, with various quenching effects by metallic species reported in the literature. Here, we report the first case of metal enhanced fluorescence (MEF) of surfactant-coated carbon nanotubes on nanostructured gold substrates. The photoluminescence quantum yield of SWNTs is observed to be enhanced more than 10-fold. The dependence of fluorescence enhancement on metal-nanotube distance and on the surface plasmon resonance (SPR) of the gold substrate for various SWNT chiralities is measured to reveal the mechanism of enhancement. Surfactant-coated SWNTs in direct contact with metal exhibit strong MEF without quenching, suggesting a small quenching distance for SWNTs on the order of the van der Waals distance, beyond which the intrinsically fast nonradiative decay rate in nanotubes is little enhanced by metal. The metal enhanced fluorescence of SWNTs is attributed to radiative lifetime shortening through resonance coupling of SWNT emission to the reradiating dipolar plasmonic modes in the metal.

  14. Spectroscopy of Optical Excitations in Carbon Nanotubes

    Science.gov (United States)

    Ma, Yingzhong

    2006-03-01

    Understanding the optical spectra and electronic excited state dynamics of carbon naotubes is important both for fundamental research and a wide variety of potential applications. In this presentation, we will report the results of a systematic study on semiconducting single-walled carbon nanotubes (SWNTs) obtained by utilizing complementary femtosecond spectroscopic techniques, including fluorescence up-conversion, frequency-resolved transient absorption, and three-pulse photon echo peakshift (3PEPS) spectroscopy. Our efforts have focused on optically selective detection of the spectra and dynamics associated with structurally distinct semiconducting SWNT species. Using individual nanotube enriched micelle-dispersed SWNT preparations, in combination with resonant excitation and detection, has enabled us to independently access selected species, such as the (8,3), (6,5), (7,5), (11,0), (7,6) and (9,5) nanotubes. We will discuss the following topics: (1) the excitonic nature of the elementary excitation and its unambiguous identification from direct determination of the exciton binding energy for a selected semiconducting nanotube, the (8,3) tube; (2) the spectroscopic and dynamical signatures of exciton-exciton annihilation and its predominant role in governing ultrafast excited state relaxation; (3) the annihilation-concomitant exciton dissociation and the spectroscopic and dynamic features of the resulting electron-hole continuum; (4) timescales characterizing the ultrafast thermalization processes. In addition, we will demonstrate the power of 3PEPS spectroscopy to elucidate the spectral properties and dynamics of SWNTs. This work was supported by the NSF.

  15. Developing Carbon Nanotube Standards at NASA

    Science.gov (United States)

    Nikolaev, Pasha; Arepalli, Sivaram; Sosa, Edward; Gorelik, Olga; Yowell, Leonard

    2007-01-01

    Single wall carbon nanotubes (SWCNTs) are currently being produced and processed by several methods. Many researchers are continuously modifying existing methods and developing new methods to incorporate carbon nanotubes into other materials and utilize the phenomenal properties of SWCNTs. These applications require availability of SWCNTs with known properties and there is a need to characterize these materials in a consistent manner. In order to monitor such progress, it is critical to establish a means by which to define the quality of SWCNT material and develop characterization standards to evaluate of nanotube quality across the board. Such characterization standards should be applicable to as-produced materials as well as processed SWCNT materials. In order to address this issue, NASA Johnson Space Center has developed a protocol for purity and dispersion characterization of SWCNTs. The NASA JSC group is currently working with NIST, ANSI and ISO to establish purity and dispersion standards for SWCNT material. A practice guide for nanotube characterization is being developed in cooperation with NIST. Furthermore, work is in progress to incorporate additional characterization methods for electrical, mechanical, thermal, optical and other properties of SWCNTs.

  16. Remote Joule heating by a carbon nanotube

    Science.gov (United States)

    Baloch, Kamal H.; Voskanian, Norvik; Bronsgeest, Merijntje; Cumings, John

    2012-05-01

    Minimizing Joule heating remains an important goal in the design of electronic devices. The prevailing model of Joule heating relies on a simple semiclassical picture in which electrons collide with the atoms of a conductor, generating heat locally and only in regions of non-zero current density, and this model has been supported by most experiments. Recently, however, it has been predicted that electric currents in graphene and carbon nanotubes can couple to the vibrational modes of a neighbouring material, heating it remotely. Here, we use in situ electron thermal microscopy to detect the remote Joule heating of a silicon nitride substrate by a single multiwalled carbon nanotube. At least 84% of the electrical power supplied to the nanotube is dissipated directly into the substrate, rather than in the nanotube itself. Although it has different physical origins, this phenomenon is reminiscent of induction heating or microwave dielectric heating. Such an ability to dissipate waste energy remotely could lead to improved thermal management in electronic devices.

  17. Graphene nanoribbons production from flat carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Melo, W. S.; Guerini, S.; Diniz, E. M., E-mail: eduardo.diniz@ufma.br [Departamento de Física, Universidade Federal do Maranhão, São Luís - MA 65080-805 (Brazil)

    2015-11-14

    Graphene nanoribbons are of great interest for pure and applied sciences due to their unique properties which depend on the nanoribbon edges, as, for example, energy gap and antiferromagnetic coupling. Nevertheless, the synthesis of nanoribbons with well-defined edges remains a challenge. To collaborate with this subject, here we propose a new route for the production of graphene nanoribbons from flat carbon nanotubes filled with a one-dimensional chain of Fe atoms by first principles calculations based on density functional theory. Our results show that Fe-filled flat carbon nanotubes are energetically more stable than non flattened geometries. Also we find that by hydrogenation or oxygenation of the most curved region of the Fe-filled flat armchair carbon nanotube, it occurred a spontaneous production of zigzag graphene nanoribbons which have metallic or semiconducting behavior depending on the edge and size of the graphene nanoribbon. Such findings can be used to create a new method of synthesis of regular-edge carbon nanoribbons.

  18. Carbon nanotube catalysts: recent advances in synthesis, characterization and applications.

    Science.gov (United States)

    Yan, Yibo; Miao, Jianwei; Yang, Zhihong; Xiao, Fang-Xing; Yang, Hong Bin; Liu, Bin; Yang, Yanhui

    2015-05-21

    Carbon nanotubes are promising materials for various applications. In recent years, progress in manufacturing and functionalizing carbon nanotubes has been made to achieve the control of bulk and surface properties including the wettability, acid-base properties, adsorption, electric conductivity and capacitance. In order to gain the optimal benefit of carbon nanotubes, comprehensive understanding on manufacturing and functionalizing carbon nanotubes ought to be systematically developed. This review summarizes methodologies of manufacturing carbon nanotubes via arc discharge, laser ablation and chemical vapor deposition and functionalizing carbon nanotubes through surface oxidation and activation, doping of heteroatoms, halogenation, sulfonation, grafting, polymer coating, noncovalent functionalization and nanoparticle attachment. The characterization techniques detecting the bulk nature and surface properties as well as the effects of various functionalization approaches on modifying the surface properties for specific applications in catalysis including heterogeneous catalysis, photocatalysis, photoelectrocatalysis and electrocatalysis are highlighted.

  19. CARBON NANOTUBES: AN APPROACH TO NOVEL DRUG DELIVERY SYSTEM

    Directory of Open Access Journals (Sweden)

    M. H. Alai et al.

    2012-01-01

    Full Text Available Carbon nanotubes are cylindrical carbon molecules have novel properties, making them potentially useful in many applications in nanotechnology, electronics, optics, and other fields of material science as well as potential uses in architectural fields. They have unique electronic, mechanical, optical and chemical properties that make them good candidates for a wide variety of applications, including drug transporters, new therapeutics, delivery systems and diagnostics. Their unique surface area, stiffness, strength and resilience have led to much excitement in the field of pharmacy. Nanotubes are categorized as single-walled nanotubes, multiple walled nanotubes. Various techniques have been developed to produce nanotubes in sizeable quantities, including arc discharge, laser ablation, chemical vapor deposition. They can pass through membranes, carrying therapeutic drugs, vaccines and nucleic acids deep into the cell to targets previously unreachable. Purification of the tubes can be divided into a couple of main techniques: oxidation, acid treatment, annealing, sonication, filtering and functionalization techniques. The main problem of insolubility in aqueous media has been solved by developing a synthetic protocol that allows highly water-soluble carbon NTs to be obtained. The modifications are done to improve efficiency of carbon nanotubes by formulating luminescent carbon nanotubes, ultrathin carbon nanoneedles, magnetically guided nanotubes. The application of carbon nanotube in tissue engineering, drug carrier release system, wound healing, in cancer treatment and as biosensor. Researchers have recently developed a new approach to Boron Neutron Capture Therapy in the treatment of cancer using substituted Carborane-Appended Water-Soluble single-wall carbon nanotubes.

  20. Van der Waals interaction between two crossed carbon nanotubes

    OpenAIRE

    Zhbanov, Alexander I.; Pogorelov, Evgeny G.; Chang, Yia-Chung

    2008-01-01

    The analytical expressions for the van der Waals potential energy and force between two crossed carbon nanotubes are presented. The Lennard-Jones potential for two carbon atoms and the method of the smeared out approximation suggested by L.A. Girifalco were used. The exact formula is expressed in terms of rational and elliptical functions. The potential and force for carbon nanotubes were calculated. The uniform potential curves for single- and multi- wall nanotubes were plotted. The equilibr...

  1. Raman spectroscopy on carbon nanotubes at high pressure

    OpenAIRE

    Loa, I.

    2003-01-01

    Raman spectroscopy has been the most extensively employed method to study carbon nanotubes at high pressures. This review covers reversible pressure-induced changes of the lattice dynamics and structure of single- and multi-wall carbon nanotubes as well as irreversible transformations induced by high pressures. The interplay of covalent and van-der-Waals bonding in single-wall nanotube bundles and a structural distortion near 2 GPa are discussed in detail. Attempts of transforming carbon nano...

  2. Varied morphology carbon nanotubes and method for their manufacture

    Science.gov (United States)

    Li, Wenzhi; Wen, Jian Guo; Ren, Zhi Feng

    2007-01-02

    The present invention describes the preparation of carbon nanotubes of varied morphology, catalyst materials for their synthesis. The present invention also describes reactor apparatus and methods of optimizing and controlling process parameters for the manufacture carbon nanotubes with pre-determined morphologies in relatively high purity and in high yields. In particular, the present invention provides methods for the preparation of non-aligned carbon nanotubes with controllable morphologies, catalyst materials and methods for their manufacture.

  3. Thermogravimetric Analysis of Single-Wall Carbon Nanotubes

    Science.gov (United States)

    Arepalli, Sivram; Nikolaev, Pavel; Gorelik, Olga

    2010-01-01

    An improved protocol for thermogravimetric analysis (TGA) of samples of single-wall carbon nanotube (SWCNT) material has been developed to increase the degree of consistency among results so that meaningful comparisons can be made among different samples. This improved TGA protocol is suitable for incorporation into the protocol for characterization of carbon nanotube material. In most cases, TGA of carbon nanotube materials is performed in gas mixtures that contain oxygen at various concentrations. The improved protocol is summarized.

  4. A statistical mechanics model of carbon nanotube macro-films

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Carbon nanotube macro-films are two-dimensional films with micrometer thickness and centimeter by centimeter in-plane dimension.These carbon nanotube macroscopic assemblies have attracted significant attention from the material and mechanics communities recently because they can be easily handled and tailored to meet specific engineering needs.This paper reports the experimental methods on the preparation and characterization of single-walled carbon nanotube macro-films,and a statistical mechanics model on ...

  5. Simulations of Electrophoretic RNA Transport Through Transmembrane Carbon Nanotubes

    OpenAIRE

    Zimmerli, Urs; Koumoutsakos, Petros

    2008-01-01

    The study of interactions between carbon nanotubes and cellular components, such as membranes and biomolecules, is fundamental for the rational design of nanodevices interfacing with biological systems. In this work, we use molecular dynamics simulations to study the electrophoretic transport of RNA through carbon nanotubes embedded in membranes. Decorated and naked carbon nanotubes are inserted into a dodecane membrane and a dimyristoylphosphatidylcholine lipid bilayer, and the system is sub...

  6. Continuous Growth of Vertically Aligned Carbon Nanotubes Forests

    OpenAIRE

    Guzman de Villoria, Roberto; Wardle, Brian L.

    2011-01-01

    Vertically aligned carbon nanotubes are one of the most promising materials due their numerous applications in flexible electronic devices, biosensors and multifunctional aircraft materials, among others. However, the costly production of aligned carbon nanotubes, generally in a batch process, prevents their commercial use. For the first time, a controlled process to grow aligned carbon nanotubes in a continuous manner is presented. Uniform growth is achieved using 2D and 3D substrates. A sig...

  7. Nanoscale Continuum Modelling of Carbon Nanotubes by Polyhedral Finite Elements

    Directory of Open Access Journals (Sweden)

    Logah Perumal

    2016-01-01

    Full Text Available As the geometry of a cell of carbon nanotube is hexagonal, a new approach is presented in modelling of single-walled carbon nanotubes using polyhedral finite elements. Effect of varying length, diameter, and thickness of carbon nanotubes on Young’s modulus is studied. Both armchair and zigzag configurations are modelled and simulated in Mathematica. Results from current approach found good agreement with the other published data.

  8. A Carbon Nanotube Cable for a Space Elevator

    Science.gov (United States)

    Bochnícek, Zdenek

    2013-01-01

    In this paper the mechanical properties of carbon nanotubes are discussed in connection with the possibility to use them for the construction of a space elevator. From the fundamental information about the structure of a carbon nanotube and the chemical bond between carbon atoms, Young's modulus and the ultimate tensile strength are…

  9. Carbon nanotube based stationary phases for microchip chromatography

    DEFF Research Database (Denmark)

    Mogensen, Klaus Bo; Kutter, Jörg Peter

    2012-01-01

    The objective of this article is to provide an overview and critical evaluation of the use of carbon nanotubes and related carbon-based nanomaterials for microchip chromatography. The unique properties of carbon nanotubes, such as a very high surface area and intriguing adsorptive behaviour, have...

  10. Electrostatic sensing and electrochemistry with single carbon nanotubes

    NARCIS (Netherlands)

    Heller, I.

    2009-01-01

    This thesis describes the experimental study of devices based on single carbon nanotubes in the context of (bio)sensing in aqueous solutions. Carbon nanotubes are cylindrical molecules of sp2- carbon, about one nanometer in diameter and typically several micrometers long, which have semiconducting o

  11. Carbon Nanotube Flexible and Stretchable Electronics

    Science.gov (United States)

    Cai, Le; Wang, Chuan

    2015-08-01

    The low-cost and large-area manufacturing of flexible and stretchable electronics using printing processes could radically change people's perspectives on electronics and substantially expand the spectrum of potential applications. Examples range from personalized wearable electronics to large-area smart wallpapers and from interactive bio-inspired robots to implantable health/medical apparatus. Owing to its one-dimensional structure and superior electrical property, carbon nanotube is one of the most promising material platforms for flexible and stretchable electronics. Here in this paper, we review the recent progress in this field. Applications of single-wall carbon nanotube networks as channel semiconductor in flexible thin-film transistors and integrated circuits, as stretchable conductors in various sensors, and as channel material in stretchable transistors will be discussed. Lastly, state-of-the-art advancement on printing process, which is ideal for large-scale fabrication of flexible and stretchable electronics, will also be reviewed in detail.

  12. Carbon Nanotube Flexible and Stretchable Electronics.

    Science.gov (United States)

    Cai, Le; Wang, Chuan

    2015-12-01

    The low-cost and large-area manufacturing of flexible and stretchable electronics using printing processes could radically change people's perspectives on electronics and substantially expand the spectrum of potential applications. Examples range from personalized wearable electronics to large-area smart wallpapers and from interactive bio-inspired robots to implantable health/medical apparatus. Owing to its one-dimensional structure and superior electrical property, carbon nanotube is one of the most promising material platforms for flexible and stretchable electronics. Here in this paper, we review the recent progress in this field. Applications of single-wall carbon nanotube networks as channel semiconductor in flexible thin-film transistors and integrated circuits, as stretchable conductors in various sensors, and as channel material in stretchable transistors will be discussed. Lastly, state-of-the-art advancement on printing process, which is ideal for large-scale fabrication of flexible and stretchable electronics, will also be reviewed in detail.

  13. Printed Carbon Nanotube Electronics and Sensor Systems.

    Science.gov (United States)

    Chen, Kevin; Gao, Wei; Emaminejad, Sam; Kiriya, Daisuke; Ota, Hiroki; Nyein, Hnin Yin Yin; Takei, Kuniharu; Javey, Ali

    2016-06-01

    Printing technologies offer large-area, high-throughput production capabilities for electronics and sensors on mechanically flexible substrates that can conformally cover different surfaces. These capabilities enable a wide range of new applications such as low-cost disposable electronics for health monitoring and wearables, extremely large format electronic displays, interactive wallpapers, and sensing arrays. Solution-processed carbon nanotubes have been shown to be a promising candidate for such printing processes, offering stable devices with high performance. Here, recent progress made in printed carbon nanotube electronics is discussed in terms of materials, processing, devices, and applications. Research challenges and opportunities moving forward from processing and system-level integration points of view are also discussed for enabling practical applications.

  14. Aerosol printed carbon nanotube strain sensor

    Science.gov (United States)

    Thompson, Bradley; Yoon, Hwan-Sik

    2012-04-01

    In recent years, printed electronics have received attention as a method to produce low-cost macro electronics on flexible substrates. In this regard, inkjet and aerosol printing have been the primary printing methods for producing passive electrical components, transistors, and a number of sensors. In this research, a custom aerosol printer was utilized to create a strain sensor capable of measuring static and dynamic strain. The proposed sensor was created by aerosol printing a multiwall carbon nanotube solution onto an aluminum beam covered with an insulating layer. After printing the carbon nanotube-based sensor, the sensor was tested under quasi-static and vibration strain conditions, and the results are presented. The results show that the printed sensor could potentially serve as an effective method for measuring dynamic strain of structural components.

  15. Advanced technology for functionalization of carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    Lingjie Meng; Chuanlong Fu; Qinghua Lu

    2009-01-01

    Functionalization of carbon nanotubes (CNTs) has attracted considerable interest in the fields of physics, chemistry, material science and biology. The functionalized CNTs exhibit improved properties enabling facile fabrication of novel nanomaterials and nanodevices. Most of the functionalization approaches developed at present could be categorized into the covalent attachment of functional groups and the non-covalent adsorption of various functional molecules onto the surface of CNTs. This review highlights recent development and our work in functionalization of carbon nanotubes, leading to bio-compatible CNTs, fluorescent CNTs and transition metal func-tionalizcd CNTs. These novel methods possess advantages such as simplified technical procedures and reduced cost of novel nanoma-terials and nanodcvices fabrication.

  16. Density controlled carbon nanotube array electrodes

    Science.gov (United States)

    Ren, Zhifeng F.; Tu, Yi

    2008-12-16

    CNT materials comprising aligned carbon nanotubes (CNTs) with pre-determined site densities, catalyst substrate materials for obtaining them and methods for forming aligned CNTs with controllable densities on such catalyst substrate materials are described. The fabrication of films comprising site-density controlled vertically aligned CNT arrays of the invention with variable field emission characteristics, whereby the field emission properties of the films are controlled by independently varying the length of CNTs in the aligned array within the film or by independently varying inter-tubule spacing of the CNTs within the array (site density) are disclosed. The fabrication of microelectrode arrays (MEAs) formed utilizing the carbon nanotube material of the invention is also described.

  17. Computation of powder diffraction patterns for carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Koloczek, J.; Burian, A

    2004-11-17

    An approach based on the Debye equations has been developed to compute the powder diffraction patterns of single-wall carbon nanotubes (CNs). A set of Cartesian coordinates of atoms which form nanotubes has been generated yielding interatomic distances. This leads to direct calculations of the kinematical diffraction profiles for nanotubes of arbitrary helicity and size.

  18. Excited State Dynamics in Carbon Nanotubes

    Science.gov (United States)

    Miyamoto, Yoshiyuki

    2004-03-01

    Carbon nanotube, one of the most promising materials for nano-technology, still suffers from its imperfection in crystalline structure that will make performance of nanotube behind theoretical limit. From the first-principles simulations, I propose efficient methods to overcome the imperfection. I show that photo-induced ion dynamics can (1) identify defects in nanotubes, (2) stabilize defected nanotubes, and (3) purify contaminated nanotubes. All of these methods can be alternative to conventional heat treatments and will be important techniques for realizing nanotube-devices. Ion dynamics under electronic excitation has been simulated with use of the computer code FPSEID (First-Principles Simulation tool for Electron Ion Dynamics) [1], which combines the time-dependent density functional method [2] to classical molecular dynamics. This very challenging approach is time-consuming but can automatically treat the level alternation of differently occupied states, and can observe initiation of non-adiabatic decay of excitation. The time-dependent Kohn-Sham equation has been solved by using the Suzuki-Trotter split operator method [3], which is a numerically stable method being suitable for plane wave basis, non-local pseudopotentials, and parallel computing. This work has been done in collaboration with Prof. Angel Rubio, Prof. David Tomanek, Dr. Savas Berber and Mina Yoon. Most of present calculations have been done by using the SX5 Vector-Parallel system in the NEC Fuchu-plant, and the Earth Simulator in Yokohama Japan. [1] O. Sugino and Y. Miyamoto, Phys. Rev. B59, 2579 (1999); ibid, B66 089901(E) (2001) [2] E. Runge and E. K. U. Gross, Phys. Rev. Lett. 52, 997 (1984). [3] M. Suzuki, J. Phys. Soc. Jpn. 61, L3015 (1992).

  19. Carbon Nanotubes by CVD and Applications

    Science.gov (United States)

    Cassell, Alan; Delzeit, Lance; Nguyen, Cattien; Stevens, Ramsey; Han, Jie; Meyyappan, M.; Arnold, James O. (Technical Monitor)

    2001-01-01

    Carbon nanotube (CNT) exhibits extraordinary mechanical and unique electronic properties and offers significant potential for structural, sensor, and nanoelectronics applications. An overview of CNT, growth methods, properties and applications is provided. Single-wall, and multi-wall CNTs have been grown by chemical vapor deposition. Catalyst development and optimization has been accomplished using combinatorial optimization methods. CNT has also been grown from the tips of silicon cantilevers for use in atomic force microscopy.

  20. Aqueous solution dispersement of carbon nanotubes

    Science.gov (United States)

    Kim, Jae-Woo (Inventor); Park, Cheol (Inventor); Choi, Sang H. (Inventor); Lillehei, Peter T. (Inventor); Harrison, Joycelyn S. (Inventor)

    2011-01-01

    Carbon nanotubes (CNTs) are dispersed in an aqueous buffer solution consisting of at least 50 weight percent water and a remainder weight percent that includes a buffer material. The buffer material has a molecular structure defined by a first end, a second end, and a middle disposed between the first and second ends. The first end is a cyclic ring with nitrogen and oxygen heteroatomes, the middle is a hydrophobic alkyl chain, and the second end is a charged group.

  1. Torsional electromechanical systems based on carbon nanotubes.

    Science.gov (United States)

    Hall, A R; Paulson, S; Cui, T; Lu, J P; Qin, L-C; Washburn, S

    2012-11-01

    Carbon nanotubes (CNTs) are among the most highly studied nanomaterials due to their unique (and intertwined) mechanical and electrical properties. Recent advances in fabrication have allowed devices to be fabricated that are capable of applying a twisting force to individual CNTs while measuring mechanical and electrical response. Here, we review major results from this emerging field of study, revealing new properties of the material itself and opening possibilities for advances in future devices.

  2. Carbon Nanotubes Reinforced Composites for Biomedical Applications

    OpenAIRE

    Wei Wang; Yuhe Zhu; Susan Liao; Jiajia Li

    2014-01-01

    This review paper reported carbon nanotubes reinforced composites for biomedical applications. Several studies have found enhancement in the mechanical properties of CNTs-based reinforced composites by the addition of CNTs. CNTs reinforced composites have been intensively investigated for many aspects of life, especially being made for biomedical applications. The review introduced fabrication of CNTs reinforced composites (CNTs reinforced metal matrix composites, CNTs reinforced polymer matr...

  3. Octagonal Defects at Carbon Nanotube Junctions

    Science.gov (United States)

    Jaskólski, W.; Pelc, M.; Chico, Leonor; Ayuela, A.

    2013-01-01

    We investigate knee-shaped junctions of semiconductor zigzag carbon nanotubes. Two dissimilar octagons appear at such junctions; one of them can reconstruct into a pair of pentagons. The junction with two octagons presents two degenerate localized states at Fermi energy (EF). The reconstructed junction has only one state near EF, indicating that these localized states are related to the octagonal defects. The inclusion of Coulomb interaction splits the localized states in the junction with two octagons, yielding an antiferromagnetic system. PMID:24089604

  4. Air Brush Fabricated Carbon Nanotube Supercapacitor Electrodes

    Science.gov (United States)

    2010-09-01

    dispersant is not contributing to the capacitance. The electrochemical, cyclic voltametry , measurements were made using a Keithley 4200 Semiconductor...reference electrode. The cyclic voltamogram (CV) was performed in potential ranges of anywhere between –0.9–0.5 V at scan rates ranging from 1–100 mV...Symbols, Acronyms, and Abbreviations AL aluminum CNT carbon nanotube Cu copper CV cyclic voltamogram ESEM environmental scanning electron microscope

  5. Nanoparticle Decoration of Carbon Nanotubes by Sputtering

    Science.gov (United States)

    2013-02-01

    on metal morphology, as does diffusion activation energy. Comparison of the metal– graphene interfa- cial energy to the surface energy of the metal...Nanotechnology 2009;20:375501–11. [17] O. Yaglioglu, Thesis . Massachusetts Institute of Technology, Department of Mechanical Engineering; 2007. [18] Venables...25] Osswald S, Flahaut E, Ye H, Gogotsi Y. Elimination of D-band in Raman spectra of double-wall carbon nanotubes by oxidation . Chem Phys Lett

  6. Thermophoresis of water droplets inside carbon nanotubes

    DEFF Research Database (Denmark)

    Zambrano, Harvey; Walther, Jens Honore; Oyarzua, Elton

    2016-01-01

    Carbon Nanotubes(CNTs) offer unique possibilities as fluid conduits with applications ranging from lab on a chip devices to encapsulation media for drug delivery. CNTs feature high mechanical strength, chemical and thermalstability and biocompatibility therefore they are promising candidates...... for nanodevice fabrication. Thermal gradients have been proposed as mechanism to drive particles, fullerenes and droplets inside CNTs. Here, by conducting Molecular Dynamics (MD) simulations, we study thermophoresis of water droplets inside CNTs. We systematically change the size of the droplets, the axial...

  7. Defect-induced loading of Pt nanoparticles on carbon nanotubes

    Science.gov (United States)

    Kim, Sung Jin; Park, Yong Jin; Ra, Eun Ju; Kim, Ki Kang; An, Kay Hyeok; Lee, Young Hee; Choi, Jae Young; Park, Chan Ho; Doo, Seok Kwang; Park, Min Ho; Yang, Cheol Woong

    2007-01-01

    Carbon nanotubes-supported Pt nanoparticles were loaded using a microwave oven on the defective carbon nanotubes generated by an additional oxidant during acid treatment. The authors' Raman spectra and x-ray diffraction analysis demonstrated that defects created during oxidation and microwave treatment acted as nucleation seeds for Pt adsorption. The generated Pt nanoparticles had the size distributions of 2-3nm and were uniformly distributed on the defects of carbon nanotubes. The authors' density functional calculations showed that the adsorption of Pt atom on the vacancy of nanotube was significantly stronger by s-p hybridization with carbon atoms near the defect site.

  8. Role of carbon nanotubes in electroanalytical chemistry: a review.

    Science.gov (United States)

    Agüí, Lourdes; Yáñez-Sedeño, Paloma; Pingarrón, José M

    2008-08-01

    This review covers recent advances in the development of new designs of electrochemical sensors and biosensors that make use of electrode surfaces modification with carbon nanotubes. Applications based on carbon nanotubes-driven electrocatalytic effects, and the construction and analytical usefulness of new hybrid materials with polymers or other nanomaterials will be treated. Moreover, electrochemical detection using carbon nanotubes-modified electrodes as detecting systems in separation techniques such as high performance liquid chromatography (HPLC) or capillary electrophoresis (CE) will be also considered. Finally, the preparation of electrochemical biosensors, including enzyme electrodes, immunosensors and DNA biosensors, in which carbon nanotubes play a significant role in their sensing performance will be separately considered.

  9. Carbon nanotubes from synthesis to in vivo biomedical applications.

    Science.gov (United States)

    Sajid, Muhammad Imran; Jamshaid, Usama; Jamshaid, Talha; Zafar, Nadiah; Fessi, H; Elaissari, Abdelhamid

    2016-03-30

    Owing to their unique and interesting properties, extensive research round the globe has been carried out on carbon nanotubes and carbon nanotubes based systems to investigate their practical usefulness in biomedical applications. The results from these studies demonstrate a great promise in their use in targeted drug delivery systems, diagnostic techniques and in bio-analytical applications. Although, carbon nanotubes possess quite interesting properties, which make them potential candidates in the biomedical science, but they also have some inherent properties which arise great concern regarding their biosafety. In this comprehensive review, we have discussed different aspects of carbon nanotubes and carbon nanotube based systems related to biomedical applications. In the beginning, a short historical account of these tiny yet powerful particles is given followed by discussion regarding their types, properties, methods of synthesis, large scale production method, purification techniques and characterization aspects of carbon nanotubes. In the second part of the review, the functionalization of carbon nanotubes is reviewed in detail, which is not only important to make them biocompatible and stable in biological systems but also render them a great property of loading various biomolecules, diagnostic and therapeutic moieties resulting in diversified applications. In the final part of the review, emphasis is given on the pharmacokinetic aspects of carbon nanotubes including administration routes, absorption mechanisms, distribution and elimination of carbon nanotubes based systems. Lastly, a comprehensive account about the potential biomedical applications has been given followed by insights into the future.

  10. Conformational changes of fibrinogen in dispersed carbon nanotubes

    Directory of Open Access Journals (Sweden)

    Park SJ

    2012-08-01

    Full Text Available Sung Jean Park,1 Dongwoo Khang21College of Pharmacy, Gachon University, Yeonsu-gu, Incheon, South Korea; 2School of Nano and Advanced Materials Science Engineering and Center for PRC and RIGET, Gyeongsang National University, Jinju, South KoreaAbstract: The conformational changes of plasma protein structures in response to carbon nanotubes are critical for determining the nanotoxicity and blood coagulation effects of carbon nanotubes. In this study, we identified that the functional intensity of carboxyl groups on carbon nanotubes, which correspond to the water dispersity or hydrophilicity of carbon nanotubes, can induce conformational changes in the fibrinogen domains. Also, elevation of carbon nanotube density can alter the secondary structures (ie, helices and beta sheets of fibrinogen. Furthermore, fibrinogen that had been in contact with the nanoparticle material demonstrated a different pattern of heat denaturation compared with free fibrinogen as a result of a variation in hydrophilicity and concentration of carbon nanotubes. Considering the importance of interactions between carbon nanotubes and plasma proteins in the drug delivery system, this study elucidated the correlation between nanoscale physiochemical material properties of carbon nanotubes and associated structural changes in fibrinogen.Keywords: carbon nanotubes, fibrinogen, nanotoxicity, conformational change, denaturation

  11. Development of matrix photoreceivers based on carbon nanotubes array

    Science.gov (United States)

    Blagov, E. V.; Gerasimenko, A. Y.; Dudin, A. A.; Ichkitidze, L. P.; Kitsyuk, E. P.; Orlov, A. P.; Pavlov, A. A.; Polokhin, A. A.; Shaman, Yu. P.

    2016-04-01

    The technology of production of matrix photoreceivers based on carbon nanotubes (CNTs) consisting of 16 sensitive elements was developed. Working wavelength range, performance and sensitivity were studied.

  12. Carbon nanotube materials for hydrogen storage

    Energy Technology Data Exchange (ETDEWEB)

    Dillon, A.C.; Parilla, P.A.; Jones, K.M.; Riker, G.; Heben, M.J. [National Renewable Energy Lab., Golden, CO (United States)

    1998-08-01

    Carbon single-wall nanotubes (SWNTs) are essentially elongated pores of molecular dimensions and are capable of adsorbing hydrogen at relatively high temperatures and low pressures. This behavior is unique to these materials and indicates that SWNTs are the ideal building block for constructing safe, efficient, and high energy density adsorbents for hydrogen storage applications. In past work the authors developed methods for preparing and opening SWNTs, discovered the unique adsorption properties of these new materials, confirmed that hydrogen is stabilized by physical rather than chemical interactions, measured the strength of interaction to be {approximately} 5 times higher than for adsorption on planar graphite, and performed infrared absorption spectroscopy to determine the chemical nature of the surface terminations before, during, and after oxidation. This year the authors have made significant advances in synthesis and characterization of SWNT materials so that they can now prepare gram quantities of high-purity SWNT samples and measure and control the diameter distribution of the tubes by varying key parameters during synthesis. They have also developed methods which purify nanotubes and cut nanotubes into shorter segments. These capabilities provide a means for opening the tubes which were unreactive to the oxidation methods that successfully opened tubes, and offer a path towards organizing nanotube segments to enable high volumetric hydrogen storage densities. They also performed temperature programmed desorption spectroscopy on high purity carbon nanotube material obtained from collaborator Prof. Patrick Bernier and finished construction of a high precision Seivert`s apparatus which will allow the hydrogen pressure-temperature-composition phase diagrams to be evaluated for SWNT materials.

  13. Fast Electromechanical Switches Based on Carbon Nanotubes

    Science.gov (United States)

    Kaul, Anupama; Wong, Eric; Epp, Larry

    2008-01-01

    Electrostatically actuated nanoelectromechanical switches based on carbon nanotubes have been fabricated and tested in a continuing effort to develop high-speed switches for a variety of stationary and portable electronic equipment. As explained below, these devices offer advantages over electrostatically actuated microelectromechanical switches, which, heretofore, have represented the state of the art of rapid, highly miniaturized electromechanical switches. Potential applications for these devices include computer memories, cellular telephones, communication networks, scientific instrumentation, and general radiation-hard electronic equipment. A representative device of the present type includes a single-wall carbon nanotube suspended over a trench about 130 nm wide and 20 nm deep in an electrically insulating material. The ends of the carbon nanotube are connected to metal electrodes, denoted the source and drain electrodes. At bottom of the trench is another metal electrode, denoted the pull electrode (see figure). In the off or open switch state, no voltage is applied, and the nanotube remains out of contact with the pull electrode. When a sufficiently large electric potential (switching potential) is applied between the pull electrode and either or both of the source and drain electrodes, the resulting electrostatic attraction bends and stretches the nanotube into contact with the pull electrode, thereby putting the switch into the "on" or "closed" state, in which substantial current (typically as much as hundreds of nanoamperes) is conducted. Devices of this type for use in initial experiments were fabricated on a thermally oxidized Si wafer, onto which Nb was sputter-deposited for use as the pull-electrode layer. Nb was chosen because its refractory nature would enable it to withstand the chemical and thermal conditions to be subsequently imposed for growing carbon nanotubes. A 200- nm-thick layer of SiO2 was formed on top of the Nb layer by plasma

  14. Carbon Nanotube Paper-Based Electroanalytical Devices

    Directory of Open Access Journals (Sweden)

    Youngmi Koo

    2016-04-01

    Full Text Available Here, we report on carbon nanotube paper-based electroanalytical devices. A highly aligned-carbon nanotube (HA-CNT array, grown using chemical vapor deposition (CVD, was processed to form bi-layered paper with an integrated cellulose-based Origami-chip as the electroanalytical device. We used an inverse-ordered fabrication method from a thick carbon nanotube (CNT sheet to a thin CNT sheet. A 200-layered HA-CNT sheet and a 100-layered HA-CNT sheet are explored as a working electrode. The device was fabricated using the following methods: (1 cellulose-based paper was patterned using a wax printer, (2 electrical connection was made using a silver ink-based circuit printer, and (3 three electrodes were stacked on a 2D Origami cell. Electrochemical behavior was evaluated using electrochemical impedance spectroscopy (EIS and cyclic voltammetry (CV. We believe that this platform could attract a great deal of interest for use in various chemical and biomedical applications.

  15. Fluoride and lead adsorption on carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    WANG Shuguang; LI Yanhui

    2004-01-01

    The properties and applications of CNT have been studied extensively since Iijima discovered them in 1991[1,2]. They have exceptional mechanical properties and unique electrical property, highly chemical stability and large specific surface area. Thus far, they have widely potential applications in many fields. They can be used as reinforcing materials in composites[3], field emissions[4], hydrogen storage[5], nanoelectronic components[6], catalyst supports[7], adsorption material and so on. However, the study on the potential application of CNT, environmental protection field in particular, was hardly begun.Long[8] et al. reported that CNT had a significantly higher dioxin removal efficiency than that of activated carbon. The Langmuir adsorption constant is 2.7 × 1052, 1.3 × 1018 respectively. The results indicated that CNT is potential candidate for the removal of micro-organic pollutants. However, the reports on the CNT used as fluoride and heavy metal adsorbent are seldom.In this paper, A novel material, alumina supported on carbon nanotubes (Al2O3/CNT), was prepared from carbon nanotubes and Al(NO3)3. X-ray diffraction (XRD) spectra demonstrate that alumina is amorphous, and scanning electron microscope (SEM) images show that CNT and alumina are homogeneously mixed. Furthermore, the fluoride adsorption behavior on the surface of Al2O3/CNT has been investigated and compared with other adsorbents. The results indicate that Al2O3/CNT has a high adsorption capacity, with a saturation adsorption capacity of 39.4 mg/g. It is also found that the adsorption capacity of Al2O3/CNT is 3.0~4.5 times that of γ-Al2O3while almost equal to that of IRA-410 polymeric resin at 25 ℃. The adsorption isotherms of fluoride on Al2O3/CNT is fit the Freundlich equation well, optimal pH ranging from 5.0 to 9.0.Also in this paper, a novel material, modified carbon nanotubes (CNT), was prepared from carbon nanotubes and HNO3 under boiling condition. Infrared spectroscopy (IR

  16. Carbon Nanotubes:from Nanoscale Building Blocks to Macrostructures

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    1 Results Carbon nanotubes (CNTs) have fascinating properties.In order to use these novel one-dimensional structures for applications such as in nano-electronic,nano-mechanical and electrochemical energy storage device and as structural elements in various composites,the structure of nanotubes needs to be tailored and various architectures and macroscale assembles have to be configured using nanotube building blocks.Nanotube macrostructures are macroscopically organized groups of CNTs,which are expecte...

  17. Electronic transport properties of metallic single-walled carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    曹觉先; 颜晓红; 肖杨; 丁建文

    2003-01-01

    We have calculated the differential conductance of metallic carbon nanotubes by the scatter matrix method. It is found that the differential conductance of metallic nanotube-based devices oscillates as a function of the bias voltage between the two leads and the gate voltage. Oscillation period T is directly proportional to the reciprocal of nanotube length. In addition, we found that electronic transport properties are sensitive to variation of the length of the nanotube.

  18. Carbon nanotubes linked with pitavastatin: synthesis and characterisation.

    Science.gov (United States)

    Borowiak-Palen, E; Skupin, P; Kruszynska, M; Sobotta, L; Mielcarek, J

    2011-04-01

    The paper presents a study on functionalisation of multi-walled carbon nanotubes in the area of lattice defects and an attempt to bind the nanotubes with pitavastatin. Carbon nanotubes were synthesised by alcohol-chemical vapour deposition in the presence of the catalyst Fe-Co/MgO. The nanotubes were purified and the product was subjected to chemical functionalisation. Functional groups were introduced in the reaction of the purified nanotubes with thionyl chloride to obtain acidic chlorides linked to pitavastatin. The properties and structure of the nanotubes were analysed by FT-IR and Raman spectroscopies, transmission electron microscopy and liquid chromatography coupled with mass spectrometry. Photochemical stability of pitavastatin linked with carbon nanotubes has been found to be increased.

  19. Fluid flow in carbon nanotubes and nanopipes

    Science.gov (United States)

    Whitby, M.; Quirke, N.

    2007-02-01

    Nanoscale carbon tubes and pipes can be readily fabricated using self-assembly techniques and they have useful electrical, optical and mechanical properties. The transport of liquids along their central pores is now of considerable interest both for testing classical theories of fluid flow at the nanoscale and for potential nanofluidic device applications. In this review we consider evidence for novel fluid flow in carbon nanotubes and pipes that approaches frictionless transport. Methods for controlling such flow and for creating functional device architectures are described and possible applications are discussed.

  20. Terahertz Response of Carbon Nanotubes and Graphene

    Science.gov (United States)

    Kawano, Yukio

    2015-12-01

    The terahertz (THz) research field is expected to serve as a new platform for studying low-energy excitation in solids and higher-order structures in large molecules, and for realizing applications in medicine, agriculture, security, and high-capacity communications. The THz frequency region, however, is located between the electronic and photonic bands, hampering the development of basic components like detectors and sources. This article presents an overview of basic background information about THz waves and THz detector applications and describes the THz response of carbon-based low-dimensional systems, such as single carbon nanotubes (CNT), CNT-array films, and graphene.

  1. Quantum transport in carbon nanotubes

    NARCIS (Netherlands)

    Jarillo-Herrero, P.D.

    2005-01-01

    Electronic transport through nanostructures can be very different from trans- port in macroscopic conductors, especially at low temperatures. Carbon na- notubes are tiny cylinders made of carbon atoms. Their remarkable electronic and mechanical properties, together with their small size (a few nm in

  2. Self-assembly of single-walled carbon nanotubes into multiwalled carbon nanotubes in water: molecular dynamics simulations.

    Science.gov (United States)

    Zou, Jian; Ji, Baohua; Feng, Xi-Qiao; Gao, Huajian

    2006-03-01

    We report discoveries from a series of molecular dynamics simulations that single-walled carbon nanotubes, with different diameters, lengths, and chiralities, can coaxially self-assemble into multiwalled carbon nanotubes in water via spontaneous insertion of smaller tubes into larger ones. The assembly process is tube-size-dependent, and the driving force is primarily the intertube van der Waals interactions. The simulations also suggest that a multiwalled carbon nanotube may be separated into single-walled carbon nanotubes under appropriate solvent conditions. This study suggests possible bottom-up self-assembly routes for the fabrication of novel nanodevices and systems.

  3. Carbon nanotube materials for hydrogen storage

    Energy Technology Data Exchange (ETDEWEB)

    Dillon, A.C.; Jones, K.M.; Heben, M.J. [National Renewable Energy Lab., Golden, CO (United States)

    1996-10-01

    Hydrogen burns pollution-free and may be produced from renewable energy resources. It is therefore an ideal candidate to replace fossil fuels as an energy carrier. However, the lack of a convenient and cost-effective hydrogen storage system greatly impedes the wide-scale use of hydrogen in both domestic and international markets. Although several hydrogen storage options exist, no approach satisfies all of the efficiency, size, weight, cost and safety requirements for transportation or utility use. A material consisting exclusively of micropores with molecular dimensions could simultaneously meet all of the requirements for transportation use if the interaction energy for hydrogen was sufficiently strong to cause hydrogen adsorption at ambient temperatures. Small diameter ({approx}1 mm) carbon single-wall nanotubes (SWNTs) are elongated micropores of molecular dimensions, and materials composed predominantly of SWNTs may prove to be the ideal adsorbent for ambient temperature storage of hydrogen. Last year the authors reported that hydrogen could be adsorbed on arc-generated soots containing 12{Angstrom} diameter nanotubes at temperatures in excess of 285K. In this past year they have learned that such adsorption does not occur on activated carbon materials, and that the cobalt nanoparticles present in their arc-generated soots are not responsible for the hydrogen which is stable at 285 K. These results indicate that enhanced adsorption forces within the internal cavities of the SWNTs are active in stabilizing hydrogen at elevated temperatures. This enhanced stability could lead to effective hydrogen storage under ambient temperature conditions. In the past year the authors have also demonstrated that single-wall carbon nanotubes in arc-generated soots may be selectively opened by oxidation in H{sub 2}O resulting in improved hydrogen adsorption, and they have estimated experimentally that the amount of hydrogen stored is {approximately}10% of the nanotube weight.

  4. Nanotube substituted source/drain regions for carbon nanotube transistors for VLSI circuits.

    Science.gov (United States)

    Dutta, Shibesh; Shankar, Balakrishnan

    2011-12-01

    Aggressive scaling of silicon technology over the years has pushed CMOS devices to their fundamental limits. Pioneering works on carbon nanotube during the last decade possessing exceptional electrical properties have provided an intriguing solution for high performance integrated circuits. So far, at best, carbon nanotubes have been considered only for the channel, with metal electrodes being used for source/drain. Here, alternative schemes of 'All-Nanotube' transistor are presented where even the transistor components are derived from carbon nanotubes which hold the promise for smaller, faster, denser and more power efficient electronics.

  5. Carbon nanotube-based functional materials for optical limiting.

    Science.gov (United States)

    Chen, Yu; Lin, Ying; Liu, Ying; Doyle, James; He, Nan; Zhuang, Xiaodong; Bai, Jinrui; Blau, Werner J

    2007-01-01

    Optical limiting is an important application of nonlinear optics, useful for the protection of human eyes, optical elements, and optical sensors from intense laser pulses. An optical limiter is such a device that strongly attenuates high intensity light and potentially damaging light such as focused laser beams, whilst allowing for the high transmission of ambient light. Optical limiting properties of carbon nanotube suspensions, solubilized carbon nanotubes, small molecules doped carbon nanotubes and polymer/carbon nanotube composites have been reviewed. The optical limiting responses of carbon nanotube suspensions are shown to be dominated by nonlinear scattering as a result of thermally induced solvent-bubble formation and sublimation of the nanotubes, while the solubilized carbon nanotubes optically limit through nonlinear absorption mechanism and exhibit significant solution-concentration-dependent optical limiting responses. In the former case the optical limiting results are independent of nanotube concentrations at the same linear transmittance as that of the solubilized systems. Many efforts have been invested into the research of polymer/carbon nanotube composites in an attempt to allow for the fabrication of films required for the use of nanotubes in a real optical limiting application. The higher carbon nanotube content samples block the incident light more effectively at higher incident energy densities or intensities. The optical limiting mechanism of these composite materials is quite complicated. Besides nonlinear scattering contribution to the optical limiting, there may also be other contributions e.g., nonlinear absorption, nonlinear refraction, electronic absorption and others to the optical limiting. Further improvements in the optical limiting efficiency of the composites and in the dispersion and alignment properties of carbon nanotubes in the polymer matrix could be realized by variation of both nanostructured guest and polymer host, and by

  6. Oscillation of carbon molecules inside carbon nanotube bundles

    Science.gov (United States)

    Thamwattana, Ngamta; Cox, Barry J.; Hill, James M.

    2009-04-01

    In this paper, we investigate the mechanics of a nanoscaled gigahertz oscillator comprising a carbon molecule oscillating within the centre of a uniform concentric ring or bundle of carbon nanotubes. Two kinds of oscillating molecules are considered, which are a carbon nanotube and a C60 fullerene. Using the Lennard-Jones potential and the continuum approach, we obtain a relation between the bundle radius and the radii of the nanotubes forming the bundle, as well as the optimum bundle size which gives rise to the maximum oscillatory frequency for both the nanotube-bundle and the C60-bundle oscillators. While previous studies in this area have been undertaken through molecular dynamics simulations, this paper emphasizes the use of applied mathematical modelling techniques, which provides considerable insight into the underlying mechanisms of the nanoscaled oscillators. The paper presents a synopsis of the major results derived in detail by the present authors (Cox et al 2007 Proc. R. Soc. A 464 691-710 and Cox et al 2007 J. Phys. A: Math. Theor. 40 13197-208).

  7. Chaotic region of elastically restrained single-walled carbon nanotube

    Science.gov (United States)

    Hu, Weipeng; Song, Mingzhe; Deng, Zichen; Zou, Hailin; Wei, Bingqing

    2017-02-01

    The occurrence of chaos in the transverse oscillation of the carbon nanotube in all of the precise micro-nano mechanical systems has a strong impact on the stability and the precision of the micro-nano systems, the conditions of which are related with the boundary restraints of the carbon nanotube. To generalize some transverse oscillation problems of the carbon nanotube studied in current references, the elastic restraints at both ends of the single-walled carbon nanotube are considered by means of rotational and translational springs to investigate the effects of the boundary restraints on the chaotic properties of the carbon nanotube in this paper. Based on the generalized multi-symplectic theory, both the generalized multi-symplectic formulations for the governing equation describing the transverse oscillation of the single-walled carbon nanotube subjected to the transverse load and the constraint equations resulting from the elastic restraints are presented firstly. Then, the structure-preserving scheme with discrete constraint equations is constructed to simulate the transverse oscillation process of the carbon nanotube. Finally, the chaotic region of the carbon nanotube is captured, and the oscillations of the two extreme cases (including simply supported and cantilever) are investigated in the numerical investigations. From the numerical results, it can be concluded that the relative bending stiffness coefficient and the absolute bending stiffness coefficients at both ends of the carbon nanotube are two important factors that affect the chaotic region of the carbon nanotube, which provides guidance on the design and manufacture of precise micro-nano mechanical systems. In addition, the different routes to the chaos of the carbon nanotube in two extreme cases are revealed.

  8. Massive radius-dependent flow slippage in carbon nanotubes

    Science.gov (United States)

    Siria, Alessandro; Secchi, Eleonora; Marbach, Sophie; Niguès, Antoine; Stein, Derek; Bocquet, Lydéric

    2016-11-01

    Nanofluidics is the frontier where the continuum picture of fluid mechanics confronts the atomic nature of matter. Recent reports indicate that carbon nanotubes exhibit exceptional water transport properties due to nearly frictionless interfaces and this has stimulated interest in nanotube-based membranes for desalination, nano-filtration, and energy harvesting. However, the fundamental mechanisms of water transport inside nanotubes and at water-carbon interfaces remain controversial, as existing theories fail to provide a satisfying explanation for the limited experimental results. We report a study of water jets emerging from single nanotubes made of carbon and boron-nitride materials. Our experiments reveal extensive and radius-dependent surface slippage in carbon nanotubes (CNT). In stark contrast, boron-nitride nanotubes (BNNT), which are crystallographically similar to CNTs but electronically different, exhibit no slippage. This shows that slippage originates in subtle atomic-scale details of the solid-liquid interface. ERC StG - NanoSOFT.

  9. Mechanical and Electrical Properties of Organogels with Multiwall Carbon Nanotubes

    Science.gov (United States)

    Moniruzzaman, Mohammad; Winey, Karen

    2008-03-01

    Organogels are fascinating thermally reversible viscoelastic materials that are comprised of an organic liquid and low concentrations (typically organogel/carbon nanotube composites using 12-hydroxystearic acid (HSA) as the gelator molecule and pristine and carboxylated multi-wall carbon nanotubes as the nanofillers and 1,2-dichlorobenzene as the organic solvent. We have achieved significant improvements in the mechanical and electrical properties of organogels by incorporating these carbon nanotubes. For example, the linear viscoelastic regime of the HSA organogel, an indicator of the strength of the gel, extends by a factor of 4 with the incorporation of 0.2 wt% of the carboxylated nanotubes. Also, the carbon nanotubes (specially the pristine tubes) improve the electrical conductivity of the organogels, e.g. six orders of magnitude enhancement in electrical conductivity with 0.2 wt% of pristine tubes. Differential scanning calorimetry experiments indicate that the nanotubes do not affect the thermoreversibility of the organogels.

  10. Preparation of array of long carbon nanotubes and fibers therefrom

    Science.gov (United States)

    Arendt, Paul N.; DePaula, Ramond F.; Zhu, Yuntian T.; Usov, Igor O.

    2015-11-19

    An array of carbon nanotubes is prepared by exposing a catalyst structure to a carbon nanotube precursor. Embodiment catalyst structures include one or more trenches, channels, or a combination of trenches and channels. A system for preparing the array includes a heated surface for heating the catalyst structure and a cooling portion that cools gas above the catalyst structure. The system heats the catalyst structure so that the interaction between the precursor and the catalyst structure results in the formation of an array of carbon nanotubes on the catalyst structure, and cools the gas near the catalyst structure and also cools any carbon nanotubes that form on the catalyst structure to prevent or at least minimize the formation of amorphous carbon. Arrays thus formed may be used for spinning fibers of carbon nanotubes.

  11. Controlling growth of aligned carbon nanotubes from porous silicon templates

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Fabricating well-aligned carbon nanotubes, especially, on a silicon substrate is very important for their applications. In this paper, an aligned carbon nanotube array has been prepared by pyrolysis of hydrocarbons catalyzed by nickel nanoparticles embedded in porous silicon (PS) templates. High-magnification transmission electron microscopy images confirm that the nanotubes are well graphitized. The PS substrates with pore sizes between 10 and 100 nm play a control role on the growth of carbon nanotubes and the diameters of the tubes increase with the enlargement of the pores of the substrates. However, such a control role cannot be found in the macro-PS substrates.

  12. The effect of carbon nanotubes on chiral chemical reactions

    Science.gov (United States)

    Rance, Graham A.; Miners, Scott A.; Chamberlain, Thomas W.; Khlobystov, Andrei N.

    2013-02-01

    The intrinsic helicity of carbon nanotubes influences the formation of chiral molecules in chemical reactions. A racemic mixture of P and M enantiomers of nanotubes affects the enantiomeric excess of the products of the autocatalytic Soai reaction proportional to the amount of nanotubes added in the reaction mixture. An intermediate complex formed between the nanotube and the organometallic reagent is essential and explains the observed correlation between the enantiomeric distribution of products and the curvature of the carbon nanostructure. This Letter establishes a key mechanism for harnessing the helicity of nanoscale carbon surfaces for preparative organic reactions.

  13. An experimental investigation of heat transfer enhancement in minichannel: Combination of nanofluid and micro fin structure techniques

    DEFF Research Database (Denmark)

    Zhang, Ji; Diao, Yanhua; Zhao, Yaohua;

    2017-01-01

    This work experimentally studied the single-phase heat transfer and pressure drop characteristics by using two heat transfer enhancement techniques (micro fin structure and nanofluids) in multiport minichannel flat tube (MMFT). MMFT consisted of numerous parallel rectangular minichannels and is w......This work experimentally studied the single-phase heat transfer and pressure drop characteristics by using two heat transfer enhancement techniques (micro fin structure and nanofluids) in multiport minichannel flat tube (MMFT). MMFT consisted of numerous parallel rectangular minichannels...... with different micro fin numbers (N = 0, 1, 2, 3 and 4) and nanofluids with three volume concentrations (φ = 0.005%, 0.01% and 0.1%) were used as test sections and working fluids respectively. Secondly, the experiments using two combined enhancement technique were performed. By using conjunctively two...

  14. Carbon Nanotubes Synthesis via Arc Discharge with a Yttria Catalyst

    OpenAIRE

    M. I. Mohammad; Ahmed A. Moosa; J.H. Potgieter; Mustafa K. Ismael

    2013-01-01

    A facile method is proposed to use a computer controlled Arc discharge gap between graphite electrodes together with an yttria-nickel catalyst to synthesize carbon nanotubes under an Ar-H2 gases mixture atmosphere by applying different DC currents and pressure. This produces carbon nanotubes with decreased diameters and increased length. XRD evidence indicated a shift toward higher crystallinity nanotubes. Yields of the CNTs after purification were also enhanced.

  15. Site-selective radiation damage of collapsed carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Crespi, V.H. [Department of Physics, 104 Davey Lab, The Pennsylvania State University, University Park, Pennsylvania 16802-6300 (United States); Chopra, N.G.; Cohen, M.L.; Zettl, A. [Department of Physics, University of California at Berkeley and Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Radmilovic, V. [Department of Physical Metallurgy, University of Belgrade Karnegijeva 4, P.O. Box 494, Belgrade, 11001 (Yugoslavia)

    1998-10-01

    Carbon nanotubes can flatten into collapsed tubes with bulbs along either edge. The strong anisotropy in the graphitic radiation damage threshold both explains the rapid destruction of face-on flattened nanotubes and can be exploited to selectively modify the structure of edge-on flattened nanotubes, thereby creating one-dimensional sp{sup 2} carbon with noncontinuous transverse boundary conditions. {copyright} {ital 1998 American Institute of Physics.}

  16. Storage of hydrogen in floating catalytic carbon nanotubes after graphitizing

    Institute of Scientific and Technical Information of China (English)

    朱宏伟; 李雪松; 慈立杰; 徐才录; 毛宗强; 梁吉; 吴德海

    2002-01-01

    Hydrogen storage under moderate pressure (~10 Mpa) and ambient temperature (~25℃) in multi-walled carbon nanotubes (MWNTs) prepared by the floating catalyst method is investigated. The capacity of hydrogen adsorption is evaluated based on both the nanotubes diameter and morphology. Indirect evidence indicates that hydrogen adsorption not only occurs on tube surface and interiors, but also in tube interlayers. The results show that the floating catalytic carbon nanotubes might be a candidate hydrogen storage material for fuel cell electric vehicles.

  17. Carbon nanotube growth by PECVD: a review

    Energy Technology Data Exchange (ETDEWEB)

    Meyyappan, M; Delzeit, Lance; Cassell, Alan; Hash, David [NASA Ames Research Center, Moffett Field, CA 94035 (United States)

    2003-05-01

    Carbon nanotubes (CNTs), due to their unique electronic and extraordinary mechanical properties, have been receiving much attention for a wide variety of applications. Recently, plasma enhanced chemical vapour deposition (PECVD) has emerged as a key growth technique to produce vertically-aligned nanotubes. This paper reviews various plasma sources currently used in CNT growth, catalyst preparation and growth results. Since the technology is in its early stages, there is a general lack of understanding of growth mechanisms, the role of the plasma itself, and the identity of key species responsible for growth. This review is aimed at the low temperature plasma research community that has successfully addressed such issues, through plasma and surface diagnostics and modelling, in semiconductor processing and diamond thin film growth.

  18. Catalytic growth of carbon nanotubes with large inner diameters

    Directory of Open Access Journals (Sweden)

    WEI REN ZHONG

    2005-02-01

    Full Text Available Carbon nanotubes (2.4 g/g catalyst, with large inner diameters were successfully synthesized through pyrolysis of methane on a Ni–Cu–Al catalyst by adding sodium carbonate into the carbon nanotubes growth system. The inner diameter of the carbon nanotubes prepared by this method is about 20–60 nm, while their outer diameter is about 40–80 nm. Transmission electron microscopy and X-ray diffraction were employed to investigate the morphology and microstructures of the carbon nanotubes. The analyses showed that these carbon nanotubes have large inner diameters and good graphitization. The addition of sodium carbonate into the reaction system brings about a slight decrease in the methane conversion and the yield of carbon. The experimental results showed that sodium carbonate is a mildly toxic material which influenced the catalytic activity of the Ni–Cu–Al catalyst and resulted in the formation of carbon nanotubes with large inner diameters. The growth mechanism of the carbon nanotubes with large inner diameters is discussed in this paper.

  19. Catalysts for Efficient Production of Carbon Nanotubes

    Science.gov (United States)

    Sun, Ted X.; Dong, Yi

    2009-01-01

    Several metal alloys have shown promise as improved catalysts for catalytic thermal decomposition of hydrocarbon gases to produce carbon nanotubes (CNTs). Heretofore almost every experiment on the production of carbon nanotubes by this method has involved the use of iron, nickel, or cobalt as the catalyst. However, the catalytic-conversion efficiencies of these metals have been observed to be limited. The identification of better catalysts is part of a continuing program to develop means of mass production of high-quality carbon nanotubes at costs lower than those achieved thus far (as much as $100/g for purified multi-wall CNTs or $1,000/g for single-wall CNTs in year 2002). The main effort thus far in this program has been the design and implementation of a process tailored specifically for high-throughput screening of alloys for catalyzing the growth of CNTs. The process includes an integral combination of (1) formulation of libraries of catalysts, (2) synthesis of CNTs from decomposition of ethylene on powders of the alloys in a pyrolytic chemical-vapor-decomposition reactor, and (3) scanning- electron-microscope screening of the CNTs thus synthesized to evaluate the catalytic efficiencies of the alloys. Information gained in this process is put into a database and analyzed to identify promising alloy compositions, which are to be subjected to further evaluation in a subsequent round of testing. Some of these alloys have been found to catalyze the formation of carbon nano tubes from ethylene at temperatures as low as 350 to 400 C. In contrast, the temperatures typically required for prior catalysts range from 550 to 750 C.

  20. Very short functionalized carbon nanotubes for membrane applications

    NARCIS (Netherlands)

    Fonseca, A.; Reijerkerk, S.R.; Potreck, J.; Nijmeijer, D.C.; Mekhalif, Z.; Delhalle, J.

    2010-01-01

    The cutting and functionalization of carbon nanotubes is described, applying a single-step ball-mill based process. Very short carbon nanotubes bearing primary amine functions were produced, characterized and incorporated in polymeric membranes. The gas separation performance of the composite membra

  1. Apparatus for the laser ablative synthesis of carbon nanotubes

    Science.gov (United States)

    Smith, Michael W.; Jordan, Kevin

    2010-02-16

    An RF-induction heated side-pumped synthesis chamber for the production of carbon nanotubes. Such an apparatus, while capable of producing large volumes of carbon nanotubes, concurrently provides a simplified apparatus that allows for greatly reduced heat up and cool down times and flexible flowpaths that can be readily modified for production efficiency optimization.

  2. Carbon Nanotubes as Active Components for Gas Sensors

    OpenAIRE

    Wei-De Zhang; Wen-Hui Zhang

    2009-01-01

    The unique structure of carbon nanotubes endows them with fantastic physical and chemical characteristics. Carbon nanotubes have been widely studied due to their potential applications in many fields including conductive and high-strength composites, energy storage and energy conversion devices, sensors, field emission displays and radiation...

  3. Compositions and methods for cancer treatment using targeted carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Harrison, Jr., Roger G.; Resasco, Daniel E.; Neves, Luis Filipe Ferreira

    2016-11-29

    Compositions for detecting and/or destroying cancer tumors and/or cancer cells via photodynamic therapy are disclosed, as well as methods of use thereof. The compositions comprise a linking protein or peptide attached to or otherwise physically associated with a carbon nanotube to form a targeted protein-carbon nanotube complex.

  4. Re-grown aligned carbon nanotubes with improved field emission.

    Science.gov (United States)

    Lim, Xiaodai; Zhu, Yanwu; Varghese, Binni; Gao, Xingyu; Wee, Andrew Thye Shen; Sow, Chorng-Haur

    2012-01-01

    In this work, a simple technique to improve the field emission property of multi-walled carbon nanotubes is presented. Re-grown multi-walled carbon nanotubes are grown on the same substrates after the as-grown multi-walled carbon nanotubes are transferred to other substrates using polydimethylsiloxane as intermediation. For the duration of the synthesis of the re-grown multi-walled carbon nanotubes, similar synthesis parameters used in growing the as-grown multi-walled carbon nanotubes are utilized. As a form of possible application, field emission studies show -2.6 times improvement in field enhancement factor and more uniform emission for the re-grown multi-walled carbon nanotubes. In addition, the turn-on field is reduced from 2.85 V/microm to 1.40 V/microm. Such significant improvements are attributed to new emission sites comprising of sharp carbonaceous impurities encompassing both tip and upper portion of the multi-walled carbon nanotubes. As such, this technique presents a viable route for the production of multi-walled carbon nanotubes with better field emission quality.

  5. A New Application of Carbon Nanotubes Constructing Biosensor

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Carbon nanotubes used for constructing biosensor was described for the first time. Single-wall carbon nanotubes (SWNTs) functionalized with carboxylic acid groups were used to immobilize glucose oxidase forming a glucose biosensor. The biosensor response can be determined by amperometric method at a low applied potential (0.40 V).

  6. Catalytic systems of cumene oxidation based on multiwalled carbon nanotubes

    Science.gov (United States)

    Kobotaeva, N. S.; Skorokhodova, T. S.; Ryabova, N. V.

    2015-03-01

    Catalytic systems for cumene oxidation were prepared on the basis of silver-activated carbon nanotubes. Silver lies on the surface of the carbon nanotubes in the nanocrystalline state and has a size of 15-20 nm. The use of the obtained catalytic systems in cumene oxidation with molecular oxygen allowed a considerable decrease in the oxidation temperature and an increase in selectivity.

  7. Properties of Single-Wall Carbon Nanotubes with Finite Lengths

    Institute of Scientific and Technical Information of China (English)

    HU Di-Li; PAN Bi-Cai

    2001-01-01

    Carbon nanotubes with finite lengths should be natural components of future "nano devices". Based on orthogonal tight-binding molecular dynamics simulations, we report on our study of formation energies, optimal geometrical structures and active sites of carbon nanotubes with finite lengths. This should be useful to understand the properties of such natural components.

  8. Nitrogen doped carbon nanotubes : synthesis, characterization and catalysis

    NARCIS (Netherlands)

    van Dommele, S.

    2008-01-01

    Nitrogen containing Carbon Nanotubes (NCNT) have altered physical- and chemical properties with respect to polarity, conductivity and reactivity as compared to conventional carbon nanotubes (CNT) and have potential for use in electronic applications or catalysis. In this thesis the incorporation of

  9. Activity of catalase adsorbed to carbon nanotubes: effects of carbon nanotube surface properties.

    Science.gov (United States)

    Zhang, Chengdong; Luo, Shuiming; Chen, Wei

    2013-09-15

    Nanomaterials have been studied widely as the supporting materials for enzyme immobilization. However, the interactions between enzymes and carbon nanotubes (CNT) with different morphologies and surface functionalities may vary, hence influencing activities of the immobilized enzyme. To date how the adsorption mechanisms affect the activities of immobilized enzyme is not well understood. In this study the adsorption of catalase (CAT) on pristine single-walled carbon nanotubes (SWNT), oxidized single-walled carbon nanotubes (O-SWNT), and multi-walled carbon nanotubes (MWNT) was investigated. The adsorbed enzyme activities decreased in the order of O-SWNT>SWNT>MWNT. Fourier transforms infrared spectroscopy (FTIR) and circular dichrois (CD) analyses reveal more significant loss of α-helix and β-sheet of MWNT-adsorbed than SWNT-adsorbed CAT. The difference in enzyme activities between MWNT-adsorbed and SWNT-adsorbed CAT indicates that the curvature of surface plays an important role in the activity of immobilized enzyme. Interestingly, an increase of β-sheet content was observed for CAT adsorbed to O-SWNT. This is likely because as opposed to SWNT and MWNT, O-SWNT binds CAT largely via hydrogen bonding and such interaction allows the CAT molecule to maintain the rigidity of enzyme structure and thus the biological function.

  10. Carbon Nanotube Field Emission Arrays

    Science.gov (United States)

    2011-06-01

    together in hexagons and pentagons forming a sphere like a soccer ball. Fullerenes of all sizes are single molecules, which is uniquely different from the...10] Bhushan, B. Springer Handbook of Nanotechnology. Springer - Verlag. 2007 [11] Pierson, H. Handbook of Carbon, Graphite, Diamond and Fullerenes

  11. Massive radius-dependent flow slippage in carbon nanotubes

    Science.gov (United States)

    Secchi, Eleonora; Marbach, Sophie; Niguès, Antoine; Stein, Derek; Siria, Alessandro; Bocquet, Lydéric

    2016-09-01

    Measurements and simulations have found that water moves through carbon nanotubes at exceptionally high rates owing to nearly frictionless interfaces. These observations have stimulated interest in nanotube-based membranes for applications including desalination, nano-filtration and energy harvesting, yet the exact mechanisms of water transport inside the nanotubes and at the water-carbon interface continue to be debated because existing theories do not provide a satisfactory explanation for the limited number of experimental results available so far. This lack of experimental results arises because, even though controlled and systematic studies have explored transport through individual nanotubes, none has met the considerable technical challenge of unambiguously measuring the permeability of a single nanotube. Here we show that the pressure-driven flow rate through individual nanotubes can be determined with unprecedented sensitivity and without dyes from the hydrodynamics of water jets as they emerge from single nanotubes into a surrounding fluid. Our measurements reveal unexpectedly large and radius-dependent surface slippage in carbon nanotubes, and no slippage in boron nitride nanotubes that are crystallographically similar to carbon nanotubes, but electronically different. This pronounced contrast between the two systems must originate from subtle differences in the atomic-scale details of their solid-liquid interfaces, illustrating that nanofluidics is the frontier at which the continuum picture of fluid mechanics meets the atomic nature of matter.

  12. Massive radius-dependent flow slippage in carbon nanotubes.

    Science.gov (United States)

    Secchi, Eleonora; Marbach, Sophie; Niguès, Antoine; Stein, Derek; Siria, Alessandro; Bocquet, Lydéric

    2016-09-08

    Measurements and simulations have found that water moves through carbon nanotubes at exceptionally high rates owing to nearly frictionless interfaces. These observations have stimulated interest in nanotube-based membranes for applications including desalination, nano-filtration and energy harvesting, yet the exact mechanisms of water transport inside the nanotubes and at the water-carbon interface continue to be debated because existing theories do not provide a satisfactory explanation for the limited number of experimental results available so far. This lack of experimental results arises because, even though controlled and systematic studies have explored transport through individual nanotubes, none has met the considerable technical challenge of unambiguously measuring the permeability of a single nanotube. Here we show that the pressure-driven flow rate through individual nanotubes can be determined with unprecedented sensitivity and without dyes from the hydrodynamics of water jets as they emerge from single nanotubes into a surrounding fluid. Our measurements reveal unexpectedly large and radius-dependent surface slippage in carbon nanotubes, and no slippage in boron nitride nanotubes that are crystallographically similar to carbon nanotubes, but electronically different. This pronounced contrast between the two systems must originate from subtle differences in the atomic-scale details of their solid-liquid interfaces, illustrating that nanofluidics is the frontier at which the continuum picture of fluid mechanics meets the atomic nature of matter.

  13. ELECTROCHEMICAL INVESTIGATION ON CARBON NANOTUBE FILM WITH DIFFERENT PRETREATMENTS

    Institute of Scientific and Technical Information of China (English)

    C.G. Hu; W.L. Wang; Y. Ma; W. Zhu

    2003-01-01

    Wide potential windows were found at carbon nanotube film electrodes in neutral solutions after being treated with nitric acid and mixed acid. Electrochemical reversibility was investigated at carbon nanotube films with different pretreatments for ferri/ferrocyanide and quinone /hydroquinone. Carbon nanotube film electrodes presented quasi-reversible electrochemical behavior for both electrolytes. In the range of scan rate, carbon nanotube film electrodes treated with acids showed heterogeneous electron-transfer properties, which was mainly controlled by its electron state density on the surface of the film. On the whole, the carbon nanotube electrode with nitric acid treatment presented the best electrochemical behaviors, so we chose it as an analytical electrode to determine the trace compound in dilute solution. The results demonstrated that this new electrode material exhibits superior performance characteristics for the detection of azide anion.

  14. An improved fabrication method for carbon nanotube probe

    Institute of Scientific and Technical Information of China (English)

    XU Zong-wei; GUO Li-qiu; DONG Shen; ZHAO Qing-liang

    2008-01-01

    An improved arc discharge method is developed to fabricate the carbon nanotube probe.In this method,the silicon probe and the carbon nanotube were manipulated under an optical microscope.When the silicon probe and the carbon nanotube were very close,30-60 V dc or ac was applied between them,and the carbon nanotube was divided and attached to the end of the silicon probe.Comparing with the arc discharge method,the new method need not coat the silicon probe with metal in advance,which Can greatly reduce the fabrication difficulty and cost.The fabricated carbon nanotube probe exhibits the good property of hish aspect ratio and can reflect the true topography more accurately than the silicon probe.

  15. Genotoxicity and carcinogenicity risk of carbon nanotubes.

    Science.gov (United States)

    Toyokuni, Shinya

    2013-12-01

    Novel materials are often commercialized without a complete assessment of the risks they pose to human health because such assessments are costly and time-consuming; additionally, sometimes the methodology needed for such an assessment does not exist. Carbon nanotubes have the potential for widespread application in engineering, materials science and medicine. However, due to the needle-like shape and high durability of multiwalled carbon nanotubes (MWCNTs), concerns have been raised that they may induce asbestos-like pathogenicity when inhaled. Indeed, experiments in rodents supported this hypothesis. Notably, the genetic alterations in MWCNT-induced rat malignant mesothelioma were similar to those induced by asbestos. Single-walled CNTs (SWCNTs) cause mitotic disturbances in cultured cells, but thus far, there has been no report that SWCNTs are carcinogenic. This review summarizes the recent noteworthy publications on the genotoxicity and carcinogenicity of CNTs and explains the possible molecular mechanisms responsible for this carcinogenicity. The nanoscale size and needle-like rigid structure of CNTs appear to be associated with their pathogenicity in mammalian cells, where carbon atoms are major components in the backbone of many biomolecules. Publishing adverse events associated with novel materials is critically important for alerting people exposed to such materials. CNTs still have a bright future with superb economic and medical merits. However, appropriate regulation of the production, distribution and secondary manufacturing processes is required, at least to protect the workers.

  16. Spin transport in ferromagnetically contacted carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, C.; Morgan, C.; Schneider, C.M. [Peter Gruenberg Institut, PGI-6, Forschungszentrum Juelich and JARA Juelich Aachen Research Alliance, 52425 Juelich (Germany)

    2011-11-15

    We present magnetoresistance (MR) measurements on carbon nanotubes (CNTs) with different ferromagnetic leads. A sample with permalloy (Ni{sub 80}Fe{sub 20}) contacts shows the expected tunneling-type MR effect. Measurements on devices with CoPd contacts show a larger change of resistance with magnetic field. However, only minor loops are observed, which is explained with domain wall pinning. This is supported by magnetic force microscopy (MFM) measurements, which reveal a complicated bubble and stripe domain pattern. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  17. Carbon nanotubes reinforced composites for biomedical applications.

    Science.gov (United States)

    Wang, Wei; Zhu, Yuhe; Liao, Susan; Li, Jiajia

    2014-01-01

    This review paper reported carbon nanotubes reinforced composites for biomedical applications. Several studies have found enhancement in the mechanical properties of CNTs-based reinforced composites by the addition of CNTs. CNTs reinforced composites have been intensively investigated for many aspects of life, especially being made for biomedical applications. The review introduced fabrication of CNTs reinforced composites (CNTs reinforced metal matrix composites, CNTs reinforced polymer matrix composites, and CNTs reinforced ceramic matrix composites), their mechanical properties, cell experiments in vitro, and biocompatibility tests in vivo.

  18. Carbon nanotubes: present and future commercial applications.

    Science.gov (United States)

    De Volder, Michael F L; Tawfick, Sameh H; Baughman, Ray H; Hart, A John

    2013-02-01

    Worldwide commercial interest in carbon nanotubes (CNTs) is reflected in a production capacity that presently exceeds several thousand tons per year. Currently, bulk CNT powders are incorporated in diverse commercial products ranging from rechargeable batteries, automotive parts, and sporting goods to boat hulls and water filters. Advances in CNT synthesis, purification, and chemical modification are enabling integration of CNTs in thin-film electronics and large-area coatings. Although not yet providing compelling mechanical strength or electrical or thermal conductivities for many applications, CNT yarns and sheets already have promising performance for applications including supercapacitors, actuators, and lightweight electromagnetic shields.

  19. Carbon nanotubes for ultrafast fibre lasers

    Directory of Open Access Journals (Sweden)

    Chernysheva Maria

    2016-06-01

    Full Text Available Carbon nanotubes (CNTs possess both remarkable optical properties and high potential for integration in various photonic devices. We overview, here, recent progress in CNT applications in fibre optics putting particular emphasis on fibre lasers. We discuss fabrication and characterisation of different CNTs, development of CNT-based saturable absorbers (CNT-SA, their integration and operation in fibre laser cavities putting emphasis on state-of-the-art fibre lasers, mode locked using CNT-SA. We discuss new design concepts of high-performance ultrafast operation fibre lasers covering ytterbium (Yb, bismuth (Bi, erbium (Er, thulium (Tm and holmium (Ho-doped fibre lasers.

  20. Carbon nanotubes for ultrafast fibre lasers

    Science.gov (United States)

    Chernysheva, Maria; Rozhin, Aleksey; Fedotov, Yuri; Mou, Chengbo; Arif, Raz; Kobtsev, Sergey M.; Dianov, Evgeny M.; Turitsyn, Sergei K.

    2017-01-01

    Carbon nanotubes (CNTs) possess both remarkable optical properties and high potential for integration in various photonic devices. We overview, here, recent progress in CNT applications in fibre optics putting particular emphasis on fibre lasers. We discuss fabrication and characterisation of different CNTs, development of CNT-based saturable absorbers (CNT-SA), their integration and operation in fibre laser cavities putting emphasis on state-of-the-art fibre lasers, mode locked using CNT-SA. We discuss new design concepts of high-performance ultrafast operation fibre lasers covering ytterbium (Yb), bismuth (Bi), erbium (Er), thulium (Tm) and holmium (Ho)-doped fibre lasers.

  1. Increased Alignment in Carbon Nanotube Growth

    Science.gov (United States)

    Delzeit, Lance D. (Inventor)

    2007-01-01

    Method and system for fabricating an array of two or more carbon nanotube (CNT) structures on a coated substrate surface, the structures having substantially the same orientation with respect to a substrate surface. A single electrode, having an associated voltage source with a selected voltage, is connected to a substrate surface after the substrate is coated and before growth of the CNT structures, for a selected voltage application time interval. The CNT structures are then grown on a coated substrate surface with the desired orientation. Optionally, the electrode can be disconnected before the CNT structures are grown.

  2. Carbon Nanotubes Filled with Ferromagnetic Materials

    Directory of Open Access Journals (Sweden)

    Albrecht Leonhardt

    2010-08-01

    Full Text Available Carbon nanotubes (CNT filled with ferromagnetic metals like iron, cobalt or nickel are new and very interesting nanostructured materials with a number of unique properties. In this paper we give an overview about different chemical vapor deposition (CVD methods for their synthesis and discuss the influence of selected growth parameters. In addition we evaluate possible growth mechanisms involved in their formation. Moreover we show their identified structural and magnetic properties. On the basis of these properties we present different application possibilities. Some selected examples reveal the high potential of these materials in the field of medicine and nanotechnology.

  3. Carbon nanotubes: controlled growth and application

    Directory of Open Access Journals (Sweden)

    Chang Liu

    2013-01-01

    Full Text Available Notable progress has been made on the synthesis, properties and uses of carbon nanotubes (CNTs in the past two decades. However, the controlled growth of single-wall CNTs (SWCNTs with predefined and uniform structures remains a big challenge, and making full use of CNTs in applications still requires great effort. In this article, our strategies and recent progress on the controlled synthesis of SWCNTs by chemical vapor deposition are reviewed, and the applications of CNTs in lithium-ion batteries, transparent conductive films, and as connectors of metal atomic chains are discussed. Finally, future prospects for CNTs are considered.

  4. Carbon Nanotubes Reinforced Composites for Biomedical Applications

    Directory of Open Access Journals (Sweden)

    Wei Wang

    2014-01-01

    Full Text Available This review paper reported carbon nanotubes reinforced composites for biomedical applications. Several studies have found enhancement in the mechanical properties of CNTs-based reinforced composites by the addition of CNTs. CNTs reinforced composites have been intensively investigated for many aspects of life, especially being made for biomedical applications. The review introduced fabrication of CNTs reinforced composites (CNTs reinforced metal matrix composites, CNTs reinforced polymer matrix composites, and CNTs reinforced ceramic matrix composites, their mechanical properties, cell experiments in vitro, and biocompatibility tests in vivo.

  5. Octagonal Defects at Carbon Nanotube Junctions

    Directory of Open Access Journals (Sweden)

    W. Jaskólski

    2013-01-01

    Full Text Available We investigate knee-shaped junctions of semiconductor zigzag carbon nanotubes. Two dissimilar octagons appear at such junctions; one of them can reconstruct into a pair of pentagons. The junction with two octagons presents two degenerate localized states at Fermi energy (EF. The reconstructed junction has only one state near EF, indicating that these localized states are related to the octagonal defects. The inclusion of Coulomb interaction splits the localized states in the junction with two octagons, yielding an antiferromagnetic system.

  6. Solidification of gold nanoparticles in carbon nanotubes.

    Science.gov (United States)

    Arcidiacono, S; Walther, J H; Poulikakos, D; Passerone, D; Koumoutsakos, P

    2005-03-18

    The structure and the solidification of gold nanoparticles in a carbon nanotube are investigated using molecular dynamics simulations. The simulations indicate that the predicted solidification temperature of the enclosed particle is lower than its bulk counterpart, but higher than that observed for clusters placed in vacuum. A comparison with a phenomenological model indicates that, in the considered range of tube radii (R(CNT)) of 0.5 < R(CNT) < 1.6 nm, the solidification temperature depends mainly on the length of the particle with a minor dependence on R(CNT).

  7. Carbon Nanotube Integration with a CMOS Process

    OpenAIRE

    Perez, Maximiliano S.; Betiana Lerner; Resasco, Daniel E.; Pareja Obregon, Pablo D.; Pedro M. Julian; Pablo S. Mandolesi; Fabian A. Buffa; Alfredo Boselli; Alberto Lamagna

    2010-01-01

    This work shows the integration of a sensor based on carbon nanotubes using CMOS technology. A chip sensor (CS) was designed and manufactured using a 0.30 μm CMOS process, leaving a free window on the passivation layer that allowed the deposition of SWCNTs over the electrodes. We successfully investigated with the CS the effect of humidity and temperature on the electrical transport properties of SWCNTs. The possibility of a large scale integration of SWCNTs with CMOS process opens a new rout...

  8. Carbon nanotube integration with a CMOS process.

    Science.gov (United States)

    Perez, Maximiliano S; Lerner, Betiana; Resasco, Daniel E; Pareja Obregon, Pablo D; Julian, Pedro M; Mandolesi, Pablo S; Buffa, Fabian A; Boselli, Alfredo; Lamagna, Alberto

    2010-01-01

    This work shows the integration of a sensor based on carbon nanotubes using CMOS technology. A chip sensor (CS) was designed and manufactured using a 0.30 μm CMOS process, leaving a free window on the passivation layer that allowed the deposition of SWCNTs over the electrodes. We successfully investigated with the CS the effect of humidity and temperature on the electrical transport properties of SWCNTs. The possibility of a large scale integration of SWCNTs with CMOS process opens a new route in the design of more efficient, low cost sensors with high reproducibility in their manufacture.

  9. Carbon Nanotube Integration with a CMOS Process

    Directory of Open Access Journals (Sweden)

    Maximiliano S. Perez

    2010-04-01

    Full Text Available This work shows the integration of a sensor based on carbon nanotubes using CMOS technology. A chip sensor (CS was designed and manufactured using a 0.30 μm CMOS process, leaving a free window on the passivation layer that allowed the deposition of SWCNTs over the electrodes. We successfully investigated with the CS the effect of humidity and temperature on the electrical transport properties of SWCNTs. The possibility of a large scale integration of SWCNTs with CMOS process opens a new route in the design of more efficient, low cost sensors with high reproducibility in their manufacture.

  10. Superconductivity in single wall carbon nanotubes

    Directory of Open Access Journals (Sweden)

    H Yavari

    2009-08-01

    Full Text Available   By using Greens function method we first show that the effective interaction between two electrons mediated by plasmon exchange can become attractive which in turn can lead to superconductivity at a high critical temperature in a singl wall carbon nanotubes (SWCNT. The superconducting transition temperature Tc for the SWCNT (3,3 obtained by this mechanism agrees with the recent experimental result. We also show as the radius of SWCNT increases, plasmon frequency becomes lower and leads to lower Tc.

  11. Carbohydrate functionalized carbon nanotubes and their applications.

    Science.gov (United States)

    Gorityala, Bala Kishan; Ma, Jimei; Wang, Xin; Chen, Peng; Liu, Xue-Wei

    2010-08-01

    Carbon nanotubes (CNTs) have attracted tremendous attention in biomedical applications due to their molecular size and unique properties. This tutorial review summarizes the strategies to functionalize CNTs with bioactive carbohydrates, which improve their solubility, biocompatibility and biofunctionalities while preserving their desired properties. In addition, studies on the usage of carbohydrate functionalized CNTs to detect bacteria, to bind to specific lectins, to deliver glycomimetic drug molecules into cells and to probe cellular activities as biosensors are reviewed. Improvement in biocompatibility and introduction of bio-functionalities by integration of carbohydrate with CNTs are paving the way to glyconanotechnology and may provide new tools for glycobiological studies.

  12. Carbon Nanotube Array for Infrared Detection

    Science.gov (United States)

    2011-09-28

    mechanical strength, and infrared absorption efficiency are also important. [7] In these regards, thin membranes of carbon nanotubes have much to offer...Kimball, J. Carlson, D. Ziegler , G. E. Fernandes, Z. Liu, J. H. Kim, and J. Xu, “Coupled, large-format gold nanowire arrays for nanorectenna energy...Phys. Lett. 95, 231113 (2009). 10. R. Osgood III, J.B. Carlson, B.R. Kimball, D.P. Ziegler , J.R. Welch, L.E. Belton, G. Fernandes, Z. Liu, J.M. Xu

  13. Cell mobility after endocytosis of carbon nanotubes

    Science.gov (United States)

    Pirbhai, Massooma; Flores, Thomas; Jedlicka, Sabrina; Rotkin, Slava

    2013-03-01

    Directed cell movement plays a crucial role in cellular behaviors such as neuronal cell division, cell migration, and cell differentiation. There is evidence in preclinical in vivo studies that small fields have successfully been used to enhance regrowth of damages spinal cord axons but with a small success rate. Fortunately, the evolution of functional biomaterials and nanotechnology may provide promising solutions for enhancing the application of electric fields in guiding neuron migration and neurogenesis within the central nervous system. In this work, we studied how endocytosis and subsequent retention of carbon nanotubes affects the mobility of cells under the influence of an electric field, including the directed cell movement.

  14. Coating Carbon Nanotubes with Europium Oxide

    Institute of Scientific and Technical Information of China (English)

    Hui Qun CAO; Guang Yan HONG; Jing Hui YAN; Ji Lin ZHANG; Gui Xia LIU

    2003-01-01

    Carbon nanotubes (CNTS) coating with europium oxide by a simple method is reported in this letter for the first time. The CNTS were refluxed in a solution of nitric acid containing europium nitrate, and the pH value was subsequently ajusted with ammonia solution. At last, the mixture was filtered and annealed. The TEM micrograph showed that the CNTS were covered with a uniform thin layer with thickness of about 15 nm. The XRD results revealed that the CNTS were coated with europium oxide.

  15. Carbon Nanotube Integration with a CMOS Process

    Science.gov (United States)

    Perez, Maximiliano S.; Lerner, Betiana; Resasco, Daniel E.; Pareja Obregon, Pablo D.; Julian, Pedro M.; Mandolesi, Pablo S.; Buffa, Fabian A.; Boselli, Alfredo; Lamagna, Alberto

    2010-01-01

    This work shows the integration of a sensor based on carbon nanotubes using CMOS technology. A chip sensor (CS) was designed and manufactured using a 0.30 μm CMOS process, leaving a free window on the passivation layer that allowed the deposition of SWCNTs over the electrodes. We successfully investigated with the CS the effect of humidity and temperature on the electrical transport properties of SWCNTs. The possibility of a large scale integration of SWCNTs with CMOS process opens a new route in the design of more efficient, low cost sensors with high reproducibility in their manufacture. PMID:22319330

  16. Metallic Carbon Nanotubes and Ag Nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Brus, Louis E

    2014-03-04

    The goal of this DOE solar energy research was to understand how visible light interacts with matter, and how to make electric excitations evolve into separated electrons and holes in photovoltaic cells, especially in nanoparticles and nanowires. Our specific experiments focused on A) understanding plasmon enhanced spectroscopy and charge-transfer (metal-to-molecule) photochemistry on the surface of metallic particles and B) the spectroscopy and photochemistry of carbon nanotubes and graphene. I also worked closely with R. Friesner on theoretical studies of photo-excited electrons near surfaces of titanium dioxide nanoparticles; this process is relevant to the Gratzel photovoltaic cell.

  17. Molecular mechanics methods for individual carbon nanotubes and nanotube assemblies

    Science.gov (United States)

    Eberhardt, Oliver; Wallmersperger, Thomas

    2015-04-01

    Since many years, carbon nanotubes (CNTs) have been considered for a wide range of applications due to their outstanding mechanical properties. CNTs are tubular structures, showing a graphene like hexagonal lattice. Our interest in the calculation of the mechanical properties is motivated by several applications which demand the knowledge of the material behavior. One application in which the knowledge of the material behavior is vital is the CNT based fiber. Due to the excellent stiffness and strength of the individual CNTs, these fibers are expected to be a promising successor for state of the art carbon fibers. However, the mechanical properties of the fibers fall back behind the properties of individual CNTs. It is assumed that this gap in the properties is a result of the van-der-Waals interactions of the individual CNTs within the fiber. In order to understand the mechanical behavior of the fibers we apply a molecular mechanics approach. The mechanical properties of the individual CNTs are investigated by using a modified structural molecular mechanics approach. This is done by calculating the properties of a truss-beam element framework representing the CNT with the help of a chemical force field. Furthermore, we also investigate the interactions of CNTs arranged in basic CNT assemblies, mimicking the ones in a simple CNT fiber. We consider the van-der-Waals interactions in the structure and calculate the potential surface of the CNT assemblies.

  18. Carbon nanotube oscillator surface profiling device and method of use

    Science.gov (United States)

    Popescu, Adrian; Woods, Lilia M.; Bondarev, Igor V.

    2011-11-15

    The proposed device is based on a carbon nanotube oscillator consisting of a finite length outer stationary nanotube and a finite length inner oscillating nanotube. Its main function is to measure changes in the characteristics of the motion of the carbon nanotube oscillating near a sample surface, and profile the roughness of this surface. The device operates in a non-contact mode, thus it can be virtually non-wear and non-fatigued system. It is an alternative to the existing atomic force microscope (AFM) tips used to scan surfaces to determine their roughness.

  19. Ubiquity of Exciton Localization in Cryogenic Carbon Nanotubes.

    Science.gov (United States)

    Hofmann, Matthias S; Noé, Jonathan; Kneer, Alexander; Crochet, Jared J; Högele, Alexander

    2016-05-11

    We present photoluminescence studies of individual semiconducting single-wall carbon nanotubes at room and cryogenic temperatures. From the analysis of spatial and spectral features of nanotube photoluminescence, we identify characteristic signatures of unintentional exciton localization. Moreover, we quantify the energy scale of exciton localization potentials as ranging from a few to a few tens of millielectronvolts and stemming from both environmental disorder and shallow covalent side-wall defects. Our results establish disorder-induced crossover from the diffusive to the localized regime of nanotube excitons at cryogenic temperatures as a ubiquitous phenomenon in micelle-encapsulated and as-grown carbon nanotubes.

  20. Modification of Carbon Nanotube Powder Microelectrode and Nitrite Reduction

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The properties of the carbon nanotube powder microelectrodes (denoted CNTPME) are remarkably altered by anodic pretreatment and preadsorption of mediators. It seems that anodic pretreatment leads the long and tangled carbon nanotubes to be partially cut shorter, resulting in more openings as shown by TEM. Besides, the anodic pretreatment may adjust the hydrophobicity of nanotubes to match with that of Os(bpy)32+. As a result, the real surface area and the ability of adsorbing mediator Os(bpy)32+ of the nanotubes are markedly increased so as to effectively catalyze NO2- reduction in acidic solution.

  1. Modification of Carbon Nanotube Powder Microelectrode and Nitrite Reduction

    Institute of Scientific and Technical Information of China (English)

    PeiFangLIU; JunFuHU

    2002-01-01

    The properties of the carbon nanotube powder microelectroes (denoted CNTPME) are remarkably altered by anodic pretreatment and preadsorption of mediators. It seems that anodic pretreatment leads the long and tangled carbon nanotubes to be partially cut shorter, resulting in more openings as shown by TEM. Besides, the anodic pretreatment may adjust the hydrophobicity of nanotubes to match with that of Os(bpy)32+. As a result, the real surface area and the ability of adsorbing mediator Os(bpy)32+ of the nanotubes are markedly increased so as to effectively catalyze NO2- reduction in acidic solution.

  2. Carbon Nanotubes Hybrid Hydrogels in Drug Delivery: A Perspective Review

    Directory of Open Access Journals (Sweden)

    Giuseppe Cirillo

    2014-01-01

    Full Text Available The use of biologics, polymers, silicon materials, carbon materials, and metals has been proposed for the preparation of innovative drug delivery devices. One of the most promising materials in this field are the carbon-nanotubes composites and hybrid materials coupling the advantages of polymers (biocompatibility and biodegradability with those of carbon nanotubes (cellular uptake, stability, electromagnatic, and magnetic behavior. The applicability of polymer-carbon nanotubes composites in drug delivery, with particular attention to the controlled release by composites hydrogel, is being extensively investigated in the present review.

  3. Carbon nanotubes hybrid hydrogels in drug delivery: a perspective review.

    Science.gov (United States)

    Cirillo, Giuseppe; Hampel, Silke; Spizzirri, Umile Gianfranco; Parisi, Ortensia Ilaria; Picci, Nevio; Iemma, Francesca

    2014-01-01

    The use of biologics, polymers, silicon materials, carbon materials, and metals has been proposed for the preparation of innovative drug delivery devices. One of the most promising materials in this field are the carbon-nanotubes composites and hybrid materials coupling the advantages of polymers (biocompatibility and biodegradability) with those of carbon nanotubes (cellular uptake, stability, electromagnatic, and magnetic behavior). The applicability of polymer-carbon nanotubes composites in drug delivery, with particular attention to the controlled release by composites hydrogel, is being extensively investigated in the present review.

  4. Torsional wave propagation in multiwalled carbon nanotubes using nonlocal elasticity

    Science.gov (United States)

    Arda, Mustafa; Aydogdu, Metin

    2016-03-01

    Torsional wave propagation in multiwalled carbon nanotubes is studied in the present work. Governing equation of motion of multiwalled carbon nanotube is obtained using Eringen's nonlocal elasticity theory. The effect of van der Waals interaction coefficient is considered between inner and outer nanotubes. Dispersion relations are obtained and discussed in detail. Effect of nonlocal parameter and van der Waals interaction to the torsional wave propagation behavior of multiwalled carbon nanotubes is investigated. It is obtained that torsional van der Waals interaction between adjacent tubes can change the rotational direction of multiwalled carbon nanotube as in-phase or anti-phase. The group and escape velocity of the waves converge to a limit value in the nonlocal elasticity approach.

  5. Synthesis of Aligned Carbon Nanotubes by Thermal Chemical Vapor Deposition

    Institute of Scientific and Technical Information of China (English)

    LI Gang; ZHOU Ming; MA Weiwei; CAI Lan

    2009-01-01

    Single crystal silicon was found to be very beneficial to the growth of aligned carbon nanotubes by chemical vapor deposition with C2H2 as carbon source. A thin film of Ni served as catalyst was deposited on the Si substrate by the K575X Peltier Cooled High Resolution Sputter Coater before growth. The growth properties of carbon nanotubes were studied as a function of the Ni catalyst layer thickness. The diameter, growth rate and areal density of the carbon nanotubes were controlled by the initial thickness of the catalyst layer. Steric hindrance between nanotubes forces them to grow in well-aligned manner at an initial stage of growth. Transmission electron microscope analysis revealed that nanotubes grew by a tip growth mechanism.

  6. CO2 Removal from Biogas Using Carbon Nanotubes Mixed Matrix Membranes

    Directory of Open Access Journals (Sweden)

    Tutuk Djoko Kusworo

    2010-07-01

    Full Text Available A new type of mixed matrix membrane consisting of polyethersulfone (PES and carbon nanotubes (CNTs is prepared for biogas purification application. PES mixed matrix membrane with and without modification of carbon nanotubes were prepared by a dry/wet phase inversion technique using a pneumatically membrane casting machine system. The modified carbon nanotubes were prepared by treating the carbon nanotubes with chemical modification using acid treatment to allow PES chains to be grafted on carbon nanotubes surface. The results from the FESEM, DSC and FTIR analysis confirmed that chemical modification on carbon nanotubes surface had taken place. Meanwhile, the nanogaps in the interface of polymer and carbon nanotubes were appeared in the PES mixed matrix membrane with unmodified of carbon nanotubes. The modified carbon nanotubes mixed matrix membrane increases the mechanical properties and the permeability of all gases. For PES-modified carbon nanotubes mixed matrix membrane the maximum selectivity achieved for CO2/CH4 is 23.54

  7. Modeling of HiPco Process for Carbon Nanotube Production

    Science.gov (United States)

    Gokcen, T.; Dateo, C. E.; Meyyappan, M.; Colbert, D. T.; Smith, D. T.; Smith, K.; Smalley, R. E.; Arnold, James O. (Technical Monitor)

    2000-01-01

    High-pressure carbon monoxide (HiPco) reactor, developed at Rice University, is used to produce single-walled carbon nanotubes (SWNT) from gas-phase reactions of iron carbonyl and nickel carbonyl in carbon monoxide at high pressures (10 - 100 atm). Computational modeling is used to better understand the HiPco process. In the present model, decomposition of the precursor, metal cluster formation and growth, and carbon nanotube growth are addressed. Decomposition of precursor molecules is necessary to initiate metal cluster formation. The metal clusters serve as catalysts for carbon nanotube growth. Diameter of metal clusters and number of atoms in these clusters are some of the essential information for predicting carbon nanotube formation and growth, which is then modeled by Boudouard reaction (2CO ---> C(s) + CO2) with metal catalysts. The growth kinetic model is integrated with a two-dimensional axisymmetric reactor flow model to predict reactor performance.

  8. Carbon nanotubes enhanced the lead toxicity on the freshwater fish

    Science.gov (United States)

    Martinez, D. S. T.; Alves, O. L.; Barbieri, E.

    2013-04-01

    Carbon nanotubes are promising nanostructures for many applications in materials industry and biotechnology. However, it is mandatory to evaluate their toxicity and environmental implications. We evaluated nitric acid treated multiwalled carbon nanotubes (HNO3-MWCNT) toxicity in Nile tilapia (Oreochromis niloticus) and also the lead (Pb) toxicity modulation after the nanotube interaction. Industrial grade multiwalled carbon nanotubes [Ctube 100, CNT Co. Ltd] were treated with 9M HNO3 for 12h at 150°C to generate oxygenated groups on the nanotube surface, to improve water dispersion and heavy metal interaction. The HNO3-treated multiwalled carbon nanotubes were physico-chemically characterized by several techniques [e.g. TEM, FE-SEM, TGA, ζ-potential and Raman spectroscopy]. HNO3-MWCNT did not show toxicity on Nile tilapia when the concentration ranged from 0.1 to 3.0 mg/L, and the maximum exposure time was 96h. After 24, 48, 72 and 96h the LC50 values of Pb were 1.65, 1.32, 1.10 and 0.99 mg/L, respectively. To evaluate the Pb-nanotube interaction influence on the ecotoxicity, we submitted the Nile tilapia to different concentrations of Pb mixed with a non-toxic concentration of HNO3-MWCNT (1.0 mg/L). After 24, 48, 72, 96 h the LC50 values of Pb plus nanotubes were: 0.32, 0.25, 0.20, 0.18 mg/L, respectively. These values showed a synergistic effect after Pb-nanotube interaction since Pb toxicity increased over five times. X-ray energy dispersive spectroscopy (EDS) was used to confirm lead adsorption on the carbon nanotube oxidized surface. The exposure of Nile tilapia to Pb plus HNO3-MWCNT caused both oxygen consumption and ammonium excretion decrease, when compared to the control. Finally, our results show that carbon nanotubes interact with classical pollutants drawing attention to the environmental implications.

  9. Exciton Dynamics in Semiconducting Carbon Nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Graham, Matt [University of California, Berkeley; Chmeliov, Javgenij [Vilnius University, Lithuania; Ma, Yingzhong [ORNL; Shinohara, Nori [Nagoya University, Japan; Green, Alexander A. [Northwestern University, Evanston; Hersam, Mark C. [Northwestern University, Evanston; Valkunas, Leonas [Vilnius University, Lithuania; Fleming, Graham [University of California, Berkeley

    2010-01-01

    We report femtosecond transient absorption spectroscopic study on the (6, 5) single-walled carbon nanotubes and the (7, 5) inner tubes of a dominant double-walled carbon nanotube species. We found that the dynamics of exciton relaxation probed at the first transition-allowed state (E11) of a given tube type exhibits a markedly slower decay when the second transition-allowed state (E22) is excited than that measured by exciting its first transition-allowed state (E11). A linear intensity dependence of the maximal amplitude of the transient absorption signal is found for the E22 excitation, whereas the corresponding amplitude scales linearly with the square root of the E11 excitation intensity. Theoretical modeling of these experimental findings was performed by developing a continuum model and a stochastic model with explicit consideration of the annihilation of coherent excitons. Our detailed numerical simulations show that both models can reproduce reasonably well the initial portion of decay kinetics measured upon the E22 and E11 excitation of the chosen tube species, but the stochastic model gives qualitatively better agreement with the intensity dependence observed experimentally than those obtained with the continuum model.

  10. Carbon nanotube integrated multifunctional multiscale composites

    Energy Technology Data Exchange (ETDEWEB)

    Qiu Jingjing; Zhang, Chuck; Wang, Ben; Liang, Richard [High-Performance Materials Institute, Department of Industrial and Manufacturing Engineering, Florida A and M University-Florida State University College of Engineering, 2525 Pottsdamer Street, Tallahassee, FL 32310-6046 (United States)

    2007-07-11

    Carbon nanotubes (CNTs) demonstrate extraordinary properties and show great promise in enhancing out-of-plane properties of traditional polymer composites and enabling functionality, but current manufacturing challenges hinder the realization of their potential. This paper presents a method to fabricate multifunctional multiscale composites through an effective infiltration-based vacuum-assisted resin transfer moulding (VARTM) process. Multi-walled carbon nanotubes (MWNTs) were infused through and between glass-fibre tows along the through-thickness direction. Both pristine and functionalized MWNTs were used in fabricating multiscale glass-fibre-reinforced epoxy composites. It was demonstrated that the mechanical properties of multiscale composites were remarkably enhanced, especially in the functionalized MWNT multiscale composites. With only 1 wt% loading of functionalized MWNTs, tensile strength was increased by 14% and Young's modulus by 20%, in comparison with conventional fibre-reinforced composites. Moreover, the shear strength and short-beam modulus were increased by 5% and 8%, respectively, indicating the improved inter-laminar properties. The strain-stress tests also suggested noticeable enhancement in toughness. Scanning electron microscopy (SEM) characterization confirmed an enhanced interfacial bonding when functionalized MWNTs were integrated into epoxy/glass-fibre composites. The coefficient thermal expansion (CTE) of functionalized nanocomposites indicated a reduction of 25.2% compared with epoxy/glass-fibre composites. The desired improvement of electrical conductivities was also achieved. The multiscale composites indicated a way to leverage the benefits of CNTs and opened up new opportunities for high-performance multifunctional multiscale composites.

  11. Carbon nanotube integrated multifunctional multiscale composites

    Science.gov (United States)

    Qiu, Jingjing; Zhang, Chuck; Wang, Ben; Liang, Richard

    2007-07-01

    Carbon nanotubes (CNTs) demonstrate extraordinary properties and show great promise in enhancing out-of-plane properties of traditional polymer composites and enabling functionality, but current manufacturing challenges hinder the realization of their potential. This paper presents a method to fabricate multifunctional multiscale composites through an effective infiltration-based vacuum-assisted resin transfer moulding (VARTM) process. Multi-walled carbon nanotubes (MWNTs) were infused through and between glass-fibre tows along the through-thickness direction. Both pristine and functionalized MWNTs were used in fabricating multiscale glass-fibre-reinforced epoxy composites. It was demonstrated that the mechanical properties of multiscale composites were remarkably enhanced, especially in the functionalized MWNT multiscale composites. With only 1 wt% loading of functionalized MWNTs, tensile strength was increased by 14% and Young's modulus by 20%, in comparison with conventional fibre-reinforced composites. Moreover, the shear strength and short-beam modulus were increased by 5% and 8%, respectively, indicating the improved inter-laminar properties. The strain-stress tests also suggested noticeable enhancement in toughness. Scanning electron microscopy (SEM) characterization confirmed an enhanced interfacial bonding when functionalized MWNTs were integrated into epoxy/glass-fibre composites. The coefficient thermal expansion (CTE) of functionalized nanocomposites indicated a reduction of 25.2% compared with epoxy/glass-fibre composites. The desired improvement of electrical conductivities was also achieved. The multiscale composites indicated a way to leverage the benefits of CNTs and opened up new opportunities for high-performance multifunctional multiscale composites.

  12. Carbon Nanotube Thin-Film Antennas.

    Science.gov (United States)

    Puchades, Ivan; Rossi, Jamie E; Cress, Cory D; Naglich, Eric; Landi, Brian J

    2016-08-17

    Multiwalled carbon nanotube (MWCNT) and single-walled carbon nanotube (SWCNT) dipole antennas have been successfully designed, fabricated, and tested. Antennas of varying lengths were fabricated using flexible bulk MWCNT sheet material and evaluated to confirm the validity of a full-wave antenna design equation. The ∼20× improvement in electrical conductivity provided by chemically doped SWCNT thin films over MWCNT sheets presents an opportunity for the fabrication of thin-film antennas, leading to potentially simplified system integration and optical transparency. The resonance characteristics of a fabricated chlorosulfonic acid-doped SWCNT thin-film antenna demonstrate the feasibility of the technology and indicate that when the sheet resistance of the thin film is >40 ohm/sq no power is absorbed by the antenna and that a sheet resistance of antenna. The dependence of the return loss performance on the SWCNT sheet resistance is consistent with unbalanced metal, metal oxide, and other CNT-based thin-film antennas, and it provides a framework for which other thin-film antennas can be designed.

  13. Carbon nanotubes field effect transistors biosensors

    Directory of Open Access Journals (Sweden)

    M.P. Marco

    2012-03-01

    Full Text Available Carbon nanotube transistor arrays (CNTFETs wereused as biosensors to detect DNA hybridization andto recognize two anabolic steroids, stanozolol (Stzand methylboldenone (MB. Single strand DNA andantibodies specific for STz and MB were immobilizedon the carbon nanotubes (CNTs in situ in the deviceusing two different approaches: direct noncovalentbonding of antibodies to the devices and covalentlytrough a polymer previously attached to theCNTFETs. A new approach to ensure specificadsorption of the biomolecules to the nanotubeswas developed. The polymer poly(methylmethacrylate0.8-co-poly (ethyleneglycolmethacrylate0.8-co-N-succinimidyl methacrylate0.1was synthesized and bonded noncovalently to thenanotube. Aminated single-strand DNA or antibodiesspecific for Stz and MB were then attached covalentlyto the polymer. Statistically significant changes wereobserved in key transistor parameters for both DNAhybridization and steroids recognition. Regardingthe detection mechanism, in addition to chargetransfer, Schottky barrier, SB, modification, andscattering potential reported by other authors, anelectron/hole trapping mechanism leading tohysteresis modification has been determined. Thepresence of polymer seems to hinder the modulationof the electrode-CNT contact.

  14. A cell nanoinjector based on carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xing; Kis, Andras; Zettl, Alex; Bertozzi, Carolyn R.

    2007-01-30

    Technologies for introducing molecules into living cells are vital for probing the physical properties and biochemical interactions that govern the cell's behavior. Here we report the development of a nanoscale cell injection system-termed the nanoinjector-that uses carbon nanotubes to deliver cargo into cells. A single multi-walled carbon nanotube attached to an atomic force microscope tip was functionalized with cargo via a disulfide-based linker. Penetration of cell membranes with this 'nanoneedle', followed by reductive cleavage of the disulfide bonds within the cell's interior, resulted in the release of cargo inside the cells. The capability of the nanoinjector was demonstrated by injection of protein-coated quantum dots into live human cells. Single-particle tracking was employed to characterize the diffusion dynamics of injected quantum dots in the cytosol. This new technique causes no discernible membrane or cell damage, and can deliver a discrete number of molecules to the cell's interior without the requirement of a carrier solvent.

  15. Fermentation based carbon nanotube multifunctional bionic composites

    Science.gov (United States)

    Valentini, Luca; Bon, Silvia Bittolo; Signetti, Stefano; Tripathi, Manoj; Iacob, Erica; Pugno, Nicola M.

    2016-06-01

    The exploitation of the processes used by microorganisms to digest nutrients for their growth can be a viable method for the formation of a wide range of so called biogenic materials that have unique properties that are not produced by abiotic processes. Here we produced living hybrid materials by giving to unicellular organisms the nutrient to grow. Based on bread fermentation, a bionic composite made of carbon nanotubes (CNTs) and a single-cell fungi, the Saccharomyces cerevisiae yeast extract, was prepared by fermentation of such microorganisms at room temperature. Scanning electron microscopy analysis suggests that the CNTs were internalized by the cell after fermentation bridging the cells. Tensile tests on dried composite films have been rationalized in terms of a CNT cell bridging mechanism where the strongly enhanced strength of the composite is governed by the adhesion energy between the bridging carbon nanotubes and the matrix. The addition of CNTs also significantly improved the electrical conductivity along with a higher photoconductive activity. The proposed process could lead to the development of more complex and interactive structures programmed to self-assemble into specific patterns, such as those on strain or light sensors that could sense damage or convert light stimulus in an electrical signal.

  16. Fully printed flexible carbon nanotube photodetectors

    Science.gov (United States)

    Zhang, Suoming; Cai, Le; Wang, Tongyu; Miao, Jinshui; Sepúlveda, Nelson; Wang, Chuan

    2017-03-01

    Here, we report fully printed flexible photodetectors based on single-wall carbon nanotubes and the study of their electrical characteristics under laser illumination. Due to the photothermal effect and the use of high purity semiconducting carbon nanotubes, the devices exhibit gate-voltage-dependent photoresponse with the positive photocurrent or semiconductor-like behavior (conductivity increases at elevated temperatures) under positive gate biases and the negative photocurrent or metal-like behavior (conductivity decreases at elevated temperatures) under negative gate biases. Mechanism for such photoresponse is attributed to the different temperature dependencies of carrier concentration and carrier mobility, which are two competing factors that ultimately determine the photothermal effect-based photoresponse. The photodetectors built on the polyimide substrate also exhibit superior mechanical compliance and stable photoresponse after thousands of bending cycles down to a curvature radius as small as 3 mm. Furthermore, due to the low thermal conductivity of the plastic substrate, the devices show up to 6.5 fold improvement in responsivity compared to the devices built on the silicon substrate. The results presented here provide a viable path to low cost and high performance flexible photodetectors fabricated entirely by the printing process.

  17. Crystallization and mechanical properties of functionalized single-walled carbon nanotubes/polyvinylidene fluoride composites

    DEFF Research Database (Denmark)

    Ma, Jing; Iftekharul Haque, Rubaiyet; Larsen, Mikael

    2012-01-01

    Single-walled carbon nanotubes were purified and functionalized by nitric acid and octadecylamine. Raman and Fourier transform infrared spectroscopy were used to characterize the functionalization of the single-walled carbon nanotubes. Polyvinylidene flouride nanocomposites containing 1 wt......% purified or functionalized single-walled carbon nanotubes were prepared by solution blending and injection molding. The dispersion of different carbon nanotubes in dimethylformamide and in polyvinylidene flouride has been investigated. Mechanical properties show that adding single-walled carbon nanotubes...

  18. Advanced Physical Chemistry of Carbon Nanotubes

    Science.gov (United States)

    Li, Jun; Pandey, Gaind P.

    2015-04-01

    The past decade has seen a surge of exciting research and applications of carbon nanotubes (CNTs) stimulated by deeper understanding of their fundamental properties and increasing production capability. The intrinsic properties of various CNTs were found to strongly depend on their internal microstructures. This review summarizes the fundamental structure-property relations of seamless tube-like single- and multiwalled CNTs and conically stacked carbon nanofibers, as well as the organized architectures of these CNTs (including randomly stacked thin films, parallel aligned thin films, and vertically aligned arrays). It highlights the recent development of CNTs as key components in selected applications, including nanoelectronics, filtration membranes, transparent conductive electrodes, fuel cells, electrical energy storage devices, and solar cells. Particular emphasis is placed on the link between the basic physical chemical properties of CNTs and the organized CNT architectures with their functions and performance in each application.

  19. Carbon nanotube prepared from carbon monoxide by CVD method and its application as electrode materials

    Institute of Scientific and Technical Information of China (English)

    AN Yuliang; YUAN Xia; CHENG Shinan; GEN Xin

    2006-01-01

    Carbon nanotubes with larger inner diameter were synthesized by the chemical vapor deposition of carbon monoxide (CO) on iron catalyst using H2S as promoting agent.It is found that the structure and morphology of carbon nanotubes can be tailored, to some degree, by varying the experimental conditions such as precursor components and process parameters.The results show that the presence of H2S may play key role for growing Y-branched carbon nanotubes.The products were characterized by SEM, TEM, and Raman spectroscopy, respectively.Furthermore, the obtained carbon nanotubes were explored as electrode materials for supercapacitor.

  20. Sorption interactions between ethylene glycol and carbon nanotubes

    Science.gov (United States)

    Butyrskaya, E. V.; Belyakova, N. V.; Nechaeva, L. S.; Shaposhnik, V. A.; Selemenev, V. F.

    2017-03-01

    The adsorption of ethylene glycol by carbon nanoparticles is studied. Carbon nanoparticles with the highest affinity to ethylene glycol are identified, and an adsorption isotherm is constructed. Based on quantum chemical calculations of the energies of interaction between the sorbate and nanotubes with (4,4) and (6,6) chirality, a change in mechanism is revealed upon the monomolecular adsorption of ethylene glycol on carbon nanotubes, and the adsorption isotherm is thus interpreted.

  1. Carbon Nanotubes as Active Components for Gas Sensors

    Directory of Open Access Journals (Sweden)

    Wei-De Zhang

    2009-01-01

    Full Text Available The unique structure of carbon nanotubes endows them with fantastic physical and chemical characteristics. Carbon nanotubes have been widely studied due to their potential applications in many fields including conductive and high-strength composites, energy storage and energy conversion devices, sensors, field emission displays and radiation sources, hydrogen storage media, and nanometer-sized semiconductor devices, probes, and quantum wires. Some of these applications have been realized in products, while others show great potentials. The development of carbon nanotubes-based sensors has attracted intensive interest in the last several years because of their excellent sensing properties such as high selectivity and prompt response. Carbon nanotube-based gas sensors are summarized in this paper. Sensors based on single-walled, multiwalled, and well-aligned carbon nanotubes arrays are introduced. Modification of carbon nanotubes with functional groups, metals, oxides, polymers, or doping carbon nanotubes with other elements to enhance the response and selectivity of the sensors is also discussed.

  2. Differentiating Left- and Right-Handed Carbon Nanotubes by DNA.

    Science.gov (United States)

    Ao, Geyou; Streit, Jason K; Fagan, Jeffrey A; Zheng, Ming

    2016-12-28

    New structural characteristics emerge when solid-state crystals are constructed in lower dimensions. This is exemplified by single-wall carbon nanotubes, which exhibit a degree of freedom in handedness and a multitude of helicities that give rise to three distinct types of electronic structures: metals, quasi-metals, and semiconductors. Here we report the use of intrinsically chiral single-stranded DNA to achieve simultaneous handedness and helicity control for all three types of nanotubes. We apply polymer aqueous two-phase systems to select special DNA-wrapped carbon nanotubes, each of which we argue must have an ordered DNA structure that binds to a nanotube of defined handedness and helicity and resembles a well-folded biomacromolecule with innate stereoselectivity. We have screened over 300 short single-stranded DNA sequences with palindrome symmetry, leading to the selection of more than 20 distinct carbon nanotube structures that have defined helicity and handedness and cover the entire chiral angle range and all three electronic types. The mechanism of handedness selection is illustrated by a DNA sequence that adopts two distinct folds on a pair of (6,5) nanotube enantiomers, rendering them large differences in fluorescence intensity and chemical reactivity. This result establishes a first example of functionally distinguishable left- and right-handed carbon nanotubes. Taken together, our work demonstrates highly efficient enantiomer differentiation by DNA and offers a first comprehensive solution to achieve simultaneous handedness and helicity control for all three electronic types of carbon nanotubes.

  3. Carbon Nanotube Microarrays Grown on Nanoflake Substrates

    Science.gov (United States)

    Schmidt, Howard K.; Hauge, Robert H.; Pint, Cary; Pheasant, Sean

    2013-01-01

    This innovation consists of a new composition of matter where single-walled carbon nanotubes (SWNTs) are grown in aligned arrays from nanostructured flakes that are coated in Fe catalyst. This method of growth of aligned SWNTs, which can yield well over 400 percent SWNT mass per unit substrate mass, exceeds current yields for entangled SWNT growth. In addition, processing can be performed with minimal wet etching treatments, leaving aligned SWNTs with superior properties over those that exist in entangled mats. The alignment of the nanotubes is similar to that achieved in vertically aligned nanotubes, which are called "carpets. " Because these flakes are grown in a state where they are airborne in a reactor, these flakes, after growing SWNTs, are termed "flying carpets. " These flakes are created in a roll-to-roll evaporator system, where three subsequent evaporations are performed on a 100-ft (approx. =30-m) roll of Mylar. The first layer is composed of a water-soluble "release layer, " which can be a material such as NaCl. After depositing NaCl, the second layer involves 40 nm of supporting layer material . either Al2O3 or MgO. The thickness of the layer can be tuned to synthesize flakes that are larger or smaller than those obtained with a 40-nm deposition. Finally, the third layer consists of a thin Fe catalyst layer with a thickness of 0.5 nm. The thickness of this layer ultimately determines the diameter of SWNT growth, and a layer that is too thick will result in the growth of multiwalled carbon nanotubes instead of single-wall nanotubes. However, between a thickness of 0.5 nm to 1 nm, single-walled carbon nanotubes are known to be the primary constituent. After this three-layer deposition process, the Mylar is rolled through a bath of water, which allows catalyst-coated flakes to detach from the Mylar. The flakes are then collected and dried. The method described here for making such flakes is analogous to that which is used to make birefringent ink that is

  4. Carbon nanotubes on carbon fibers: Synthesis, structures and properties

    Science.gov (United States)

    Zhang, Qiuhong

    The interface between carbon fibers (CFs) and the resin matrix in traditional high performance composites is characterized by a large discontinuity in mechanical, electrical, and thermal properties which can cause inefficient energy transfer. Due to the exceptional properties of carbon nanotubes (CNTs), their growth at the surface of carbon fibers is a promising approach to controlling interfacial interactions and achieving the enhanced bulk properties. However, the reactive conditions used to grow carbon nanotubes also have the potential to introduce defects that can degrade the mechanical properties of the carbon fiber (CF) substrate. In this study, using thermal chemical vapor deposition (CVD) method, high density multi-wall carbon nanotubes have been successfully synthesized directly on PAN-based CF surface without significantly compromising tensile properties. The influence of CVD growth conditions on the single CF tensile properties and carbon nanotube (CNT) morphology was investigated. The experimental results revealed that under high temperature growth conditions, the tensile strength of CF was greatly decreased at the beginning of CNT growth process with the largest decrease observed for sized CFs. However, the tensile strength of unsized CFs with CNT was approximately the same as the initial CF at lower growth temperature. The interfacial shear strength of CNT coated CF (CNT/CF) in epoxy was studied by means of the single-fiber fragmentation test. Results of the test indicate an improvement in interfacial shear strength with the addition of a CNT coating. This improvement can most likely be attributed to an increase in the interphase yield strength as well as an improvement in interfacial adhesion due to the presence of the nanotubes. CNT/CF also offers promise as stress and strain sensors in CF reinforced composite materials. This study investigates fundamental mechanical and electrical properties of CNT/CF using nanoindentation method by designed

  5. Preparation of very long and open aligned carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    潘正伟; 常保和; 孙连峰; 钱露茜; 刘祖琴; 唐东升; 王刚; 解思深

    2000-01-01

    Very long and open aligned carbon nanotubes that reach about 2 mm long, an order of magnitude longer than previously reached, have been prepared by chemical vapor deposition over silica dioxide substrates on the surface, where iron/silica nano-composite particles are evenly positioned. The nanotubes are naturally opened at the bottom ends. The growth mechanism of the very long and open-ended nanotubes is also discussed.

  6. Multiscale carbon nanotube-carbon fiber reinforcement for advanced epoxy composites.

    Science.gov (United States)

    Bekyarova, E; Thostenson, E T; Yu, A; Kim, H; Gao, J; Tang, J; Hahn, H T; Chou, T-W; Itkis, M E; Haddon, R C

    2007-03-27

    We report an approach to the development of advanced structural composites based on engineered multiscale carbon nanotube-carbon fiber reinforcement. Electrophoresis was utilized for the selective deposition of multi- and single-walled carbon nanotubes (CNTs) on woven carbon fabric. The CNT-coated carbon fabric panels were subsequently infiltrated with epoxy resin using vacuum-assisted resin transfer molding (VARTM) to fabricate multiscale hybrid composites in which the nanotubes were completely integrated into the fiber bundles and reinforced the matrix-rich regions. The carbon nanotube/carbon fabric/epoxy composites showed approximately 30% enhancement of the interlaminar shear strength as compared to that of carbon fiber/epoxy composites without carbon nanotubes and demonstrate significantly improved out-of-plane electrical conductivity.

  7. Multiporous carbon allotropes transformed from symmetry-matched carbon nanotubes

    Directory of Open Access Journals (Sweden)

    Yingxiang Cai

    2016-06-01

    Full Text Available Carbon nanotubes (CNTs with homogeneous diameters have been proven to transform into new carbon allotropes under pressure but no studies on the compression of inhomogeneous CNTs have been reported. In this study, we propose to build new carbon allotropes from the bottom-up by applying pressure on symmetry-matched inhomogeneous CNTs. We find that the (3,0 CNT with point group C3v and the (6,0 CNT with point group C6v form an all sp3 hybridized hexagonal 3060-Carbon crystal, but the (4,0 CNT with point group D4h and the (8,0 CNT with point group D8h polymerize into a sp2+sp3 hybridized tetragonal 4080-Carbon structure. Their thermodynamic, mechanical and dynamic stabilities show that they are potential carbon allotropes to be experimentally synthesized. The multiporous structures, excellently mechanical properties and special electronic structures (semiconductive 3060-Carbon and semimetallic 4080-Carbon imply their many potential applications, such as gases purification, hydrogen storage and lightweight semiconductor devices. In addition, we simulate their feature XRD patterns which are helpful for identifying the two carbon crystals in future experimental studies.

  8. Multiporous carbon allotropes transformed from symmetry-matched carbon nanotubes

    Science.gov (United States)

    Cai, Yingxiang; Wang, Hao; Xu, Shengliang; Hu, Yujie; Liu, Ning; Xu, Xuechun

    2016-06-01

    Carbon nanotubes (CNTs) with homogeneous diameters have been proven to transform into new carbon allotropes under pressure but no studies on the compression of inhomogeneous CNTs have been reported. In this study, we propose to build new carbon allotropes from the bottom-up by applying pressure on symmetry-matched inhomogeneous CNTs. We find that the (3,0) CNT with point group C3v and the (6,0) CNT with point group C6v form an all sp3 hybridized hexagonal 3060-Carbon crystal, but the (4,0) CNT with point group D4h and the (8,0) CNT with point group D8h polymerize into a sp2+sp3 hybridized tetragonal 4080-Carbon structure. Their thermodynamic, mechanical and dynamic stabilities show that they are potential carbon allotropes to be experimentally synthesized. The multiporous structures, excellently mechanical properties and special electronic structures (semiconductive 3060-Carbon and semimetallic 4080-Carbon) imply their many potential applications, such as gases purification, hydrogen storage and lightweight semiconductor devices. In addition, we simulate their feature XRD patterns which are helpful for identifying the two carbon crystals in future experimental studies.

  9. Structural and electronic properties of carbon nanotubes under hydrostatic pressures

    Institute of Scientific and Technical Information of China (English)

    Zhang Ying; Cao Jue-Xian; Yang Wei

    2008-01-01

    We studied the structural and electronic properties of carbon nanotubes under hydrostatic pressures based on molecular dynamics simulations and first principles band structure calculations.It is found that carbon nanotubes experience a hard-to-soft transition as external pressure increases.The bulk modulus of soft phase is two orders of magnitude smaller than that of hard phase.The band structure calculations show that band gap of (10,0) nanotube increases with the increase of pressure at low pressures. Above a critical pressure (5.70GPa),band gap of (10,0) nanotube drops rapidly and becomes zero at 6.62GPa. Moreover,the calculated charge density shows that a large pressure can induce an sp2-to-sp3 bonding transition,which is confirmed by recent experiments on deformed carbon nanotubes.

  10. Toward Distinct Element Method Simulations of Carbon Nanotube Systems

    Science.gov (United States)

    Akatyeva, Evgeniya; Anderson, Tyler; Nikiforov, Ilia; Potyondy, David; Ballarini, Roberto; Dumitrica, Traian

    2011-03-01

    We propose distinct element method modeling of carbon nanotube systems. The atomic-level description of an individual nanotube is coarse-grained into a chain of spherical elements that interact by parallel bonds located at their contacts. The spherical elements can lump multiple translational unit cells of the carbon nanotube and have both translational and rotational degrees of freedom. The discrete long ranged interaction between nanotubes is included in a van der Waals contact of nonmechanical nature that acts simultaneously with the parallel bonds. The created mesoscopic model is put into service by simulating a realistic carbon nanotube ring. The ring morphology arises from the energy balance stored in both parallel and van der Waals bonds. We thank NSF CAREER under Grant No. CMMI-0747684, NSF under Grant No. CMMI 0800896.

  11. Van der Waals interaction between two crossed carbon nanotubes.

    Science.gov (United States)

    Zhbanov, Alexander I; Pogorelov, Evgeny G; Chang, Yia-Chung

    2010-10-26

    The analytical expressions for the van der Waals potential energy and force between two crossed carbon nanotubes are presented. The Lennard-Jones potential between pairs of carbon atoms and the smeared-out approximation suggested by L. A. Girifalco (J. Phys. Chem. 1992, 96, 858) were used. The exact formula is expressed in terms of rational and elliptical functions. The potential and force for carbon nanotubes were calculated. The uniform potential curves for single- and multiwall nanotubes were plotted. The equilibrium distance, maximal attractive force, and potential energy have been evaluated.

  12. Correlation and dimensional effects of trions in carbon nanotubes

    DEFF Research Database (Denmark)

    Rønnow, Troels Frimodt; Pedersen, Thomas Garm; Cornean, Horia

    2010-01-01

    We study the binding energies of singlet trions, i.e., charged excitons, in carbon nanotubes. The problem is modeled, through the effective-mass model, as a three-particle complex on the surface of a cylinder, which we investigate using both one- and two-dimensional expansions of the wave function...... are used to compute physical binding energies for a wide selection of carbon nanotubes. In addition, the dependence on dielectric screening is examined. Our findings indicate that trions are detectable at room temperature in carbon nanotubes with radius below 8 Å....

  13. Carbon nanotube-polymer composites manufacture, properties, and applications

    CERN Document Server

    Grady, Brian P

    2011-01-01

    The accessible compendium of polymers in carbon nanotubes (CNTs) Carbon nanotubes (CNTs)-extremely thin tubes only a few nanometers in diameter but able to attain lengths thousands of times greater-are prime candidates for use in the development of polymer composite materials. Bringing together thousands of disparate research works, Carbon Nanotube-Polymer Composites: Manufacture, Properties, and Applications covers CNT-polymers from synthesis to potential applications, presenting the basic science and engineering of this dynamic and complex area in an accessible, readable way. Desi

  14. Closely packed sodium and potassium nanowires in ultrathin carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Jeong Won; Hwang, Ho Jung [Chung-Ang University, Seoul (Korea, Republic of); Lee, Jun Ha; Lee, Hoong Ju [Sangmyung University, Chonan (Korea, Republic of)

    2004-07-15

    We have investigated the structural phases of sodium and potassium encapsulated in ultrathin carbon nanotubes by using a structural optimization process applied to an atomistic simulation method. As the radius of the carbon nanotubes is increased, structures are found in various phases from an atomic strand to multi-shell packs composed of coaxial cylindrical shells and in both helical and layered structures. The numbers of helical atom rows composed of coaxial tubes and the orthogonal vectors of a circular rolling of a triangular network can explain multi-shell phases of sodium and potassium in carbon nanotubes.

  15. Ultra High Energy Density Cathodes with Carbon Nanotubes

    Science.gov (United States)

    2013-12-10

    34Enhanced Capacity and Rate Capability of Carbon Nanotube Based Anodes with Titanium Contacts for Lithium Ion Batteries," ACS Nano, vol. 4, pp. 6121- 6131...2010/10/26 2010. [2] S. L. Chou, et al., "Silicon/Single-Walled Carbon Nanotube Composite Paper as a Flexible Anode Material for Lithium Ion...AFRL-RV-PS- AFRL-RV-PS- TR-2013-0170 TR-2013-0170 ULTRA HIGH ENERGY DENSITY CATHODES WITH CARBON NANOTUBES Brian J. Landi, et al. Rochester

  16. Phonon assisted thermophoretic motion of gold nanoparticles inside carbon nanotubes

    Science.gov (United States)

    Schoen, Philipp A. E.; Walther, Jens H.; Poulikakos, Dimos; Koumoutsakos, Petros

    2007-06-01

    The authors investigate the thermally driven mass transport of gold nanoparticles confined inside carbon nanotubes using molecular dynamics simulations. The observed thermophoretic motion of the gold nanoparticles correlates with the phonon dispersion exhibited by a standard carbon nanotube and, in particular, with the breathing mode of the tube. Additionally, the results show an increased static friction for gold nanoparticles confines inside a zig-zag carbon nanotube when increasing the size (length) of the nanoparticles. However, an unexpected, opposite trend is observed for the same nanoparticles inside armchair tubes.

  17. Synthesis of anisotropic gold shell on carbon nanotube

    Energy Technology Data Exchange (ETDEWEB)

    Minati, L., E-mail: luminati@fbk.eu [CNR-IFN, CSMFO Lab. (Italy); Torrengo, S. [FBK (Italy); Ischia, G. [University of Trento, Department of Industrial Engineering (Italy); Speranza, G. [FBK (Italy)

    2013-11-15

    This paper reports a simple procedure to synthesize gold-coated carbon nanotubes. The method involves the reduction of gold precursor on oxidized carbon nanotubes. UV–Visible absorption spectroscopy and electron microscopy were used to study the gold precursor reduction on the carbon nanotubes. Scanning and transmission electron microscopy analysis showed the formation of an irregular gold layer around the CNT surface. The resulting nanoparticles show an anisotropic shape with dimensions between 100 and 200 nm. This hybrid material displays an intense absorption in the near infrared range with an absorption maximum at 840 nm.

  18. Interaction of microwaves with carbon nanotubes to facilitate modification

    Science.gov (United States)

    Tour, James M. (Inventor); Dyke, Christopher A. (Inventor); Stephenson, Jason J. (Inventor); Yakobson, Boris I. (Inventor)

    2011-01-01

    The present invention is directed toward methods of crosslinking carbon nanotubes to each other using microwave radiation, articles of manufacture produced by such methods, compositions produced by such methods, and applications for such compositions and articles of manufacture. The present invention is also directed toward methods of radiatively modifying composites and/or blends comprising carbon nanotubes with microwaves, and to the compositions produced by such methods. In some embodiments, the modification comprises a crosslinking process, wherein the carbon nanotubes serve as a conduit for thermally and photolytically crosslinking the host matrix with microwave radiation.

  19. Phonon assisted thermophoretic motion of gold nanoparticles inside carbon nanotubes

    DEFF Research Database (Denmark)

    Schoen, Philipp A.E.; Walther, Jens Honore; Poulikakos, Dimos

    2007-01-01

    The authors investigate the thermally driven mass transport of gold nanoparticles confined inside carbon nanotubes using molecular dynamics simulations. The observed thermophoretic motion of the gold nanoparticles correlates with the phonon dispersion exhibited by a standard carbon nanotube and......, in particular, with the breathing mode of the tube. Additionally, the results show an increased static friction for gold nanoparticles confines inside a zig-zag carbon nanotube when increasing the size length of the nanoparticles. However, an unexpected, opposite trend is observed for the same nanoparticles...

  20. Vibrational characteristics of carbon nanotubes as nanomechanical resonators.

    Science.gov (United States)

    Kwon, Y W; Manthena, C; Oh, J J; Srivastava, D

    2005-05-01

    Using eigenvalue analysis of mass and stiffness matrices directly computed from atomistic simulations, natural frequencies and mode shapes of various carbon nanotubes are studied. The stiffness matrix was developed from the Tersoff-Brenner potential for carbon-carbon interactions. The computed frequencies of the radial breathing modes of a variety of armchair (n, n) nanotubes agree well with results obtained by others using different techniques. In addition, the study reveals diverse mode shapes such as accordion-like axial modes, lateral bending modes, torsional modes, axial shear modes, and radial breathing modes for a variety of single-wall, multi-wall, and bamboo-type carbon nanotubes. The effects of different constraints on the carbon nanotube ends on the computed frequencies and mode shapes have been investigated for possible applications in vibration sensors or electromechanical resonators.

  1. Integrating carbon nanotubes into silicon by means of vertical carbon nanotube field-effect transistors

    KAUST Repository

    Li, Jingqi

    2014-01-01

    Single-walled carbon nanotubes have been integrated into silicon for use in vertical carbon nanotube field-effect transistors (CNTFETs). A unique feature of these devices is that a silicon substrate and a metal contact are used as the source and drain for the vertical transistors, respectively. These CNTFETs show very different characteristics from those fabricated with two metal contacts. Surprisingly, the transfer characteristics of the vertical CNTFETs can be either ambipolar or unipolar (p-type or n-type) depending on the sign of the drain voltage. Furthermore, the p-type/n-type character of the devices is defined by the doping type of the silicon substrate used in the fabrication process. A semiclassical model is used to simulate the performance of these CNTFETs by taking the conductance change of the Si contact under the gate voltage into consideration. The calculation results are consistent with the experimental observations. This journal is © the Partner Organisations 2014.

  2. General hypothesis and shell model for the synthesis of semiconductor nanotubes, including carbon nanotubes

    Science.gov (United States)

    Mohammad, S. Noor

    2010-09-01

    Semiconductor nanotubes, including carbon nanotubes, have vast potential for new technology development. The fundamental physics and growth kinetics of these nanotubes are still obscured. Various models developed to elucidate the growth suffer from limited applicability. An in-depth investigation of the fundamentals of nanotube growth has, therefore, been carried out. For this investigation, various features of nanotube growth, and the role of the foreign element catalytic agent (FECA) in this growth, have been considered. Observed growth anomalies have been analyzed. Based on this analysis, a new shell model and a general hypothesis have been proposed for the growth. The essential element of the shell model is the seed generated from segregation during growth. The seed structure has been defined, and the formation of droplet from this seed has been described. A modified definition of the droplet exhibiting adhesive properties has also been presented. Various characteristics of the droplet, required for alignment and organization of atoms into tubular forms, have been discussed. Employing the shell model, plausible scenarios for the formation of carbon nanotubes, and the variation in the characteristics of these carbon nanotubes have been articulated. The experimental evidences, for example, for the formation of shell around a core, dipole characteristics of the seed, and the existence of nanopores in the seed, have been presented. They appear to justify the validity of the proposed model. The diversities of nanotube characteristics, fundamentals underlying the creation of bamboo-shaped carbon nanotubes, and the impurity generation on the surface of carbon nanotubes have been elucidated. The catalytic action of FECA on growth has been quantified. The applicability of the proposed model to the nanotube growth by a variety of mechanisms has been elaborated. These mechanisms include the vapor-liquid-solid mechanism, the oxide-assisted growth mechanism, the self

  3. Fracture of Carbon Nanotube - Amorphous Carbon Composites: Molecular Modeling

    Science.gov (United States)

    Jensen, Benjamin D.; Wise, Kristopher E.; Odegard, Gregory M.

    2015-01-01

    Carbon nanotubes (CNTs) are promising candidates for use as reinforcements in next generation structural composite materials because of their extremely high specific stiffness and strength. They cannot, however, be viewed as simple replacements for carbon fibers because there are key differences between these materials in areas such as handling, processing, and matrix design. It is impossible to know for certain that CNT composites will represent a significant advance over carbon fiber composites before these various factors have been optimized, which is an extremely costly and time intensive process. This work attempts to place an upper bound on CNT composite mechanical properties by performing molecular dynamics simulations on idealized model systems with a reactive forcefield that permits modeling of both elastic deformations and fracture. Amorphous carbon (AC) was chosen for the matrix material in this work because of its structural simplicity and physical compatibility with the CNT fillers. It is also much stiffer and stronger than typical engineering polymer matrices. Three different arrangements of CNTs in the simulation cell have been investigated: a single-wall nanotube (SWNT) array, a multi-wall nanotube (MWNT) array, and a SWNT bundle system. The SWNT and MWNT array systems are clearly idealizations, but the SWNT bundle system is a step closer to real systems in which individual tubes aggregate into large assemblies. The effect of chemical crosslinking on composite properties is modeled by adding bonds between the CNTs and AC. The balance between weakening the CNTs and improving fiber-matrix load transfer is explored by systematically varying the extent of crosslinking. It is, of course, impossible to capture the full range of deformation and fracture processes that occur in real materials with even the largest atomistic molecular dynamics simulations. With this limitation in mind, the simulation results reported here provide a plausible upper limit on

  4. Gas Composition Sensing Using Carbon Nanotube Arrays

    Science.gov (United States)

    Li, Jing; Meyyappan, Meyya

    2012-01-01

    This innovation is a lightweight, small sensor for inert gases that consumes a relatively small amount of power and provides measurements that are as accurate as conventional approaches. The sensing approach is based on generating an electrical discharge and measuring the specific gas breakdown voltage associated with each gas present in a sample. An array of carbon nanotubes (CNTs) in a substrate is connected to a variable-pulse voltage source. The CNT tips are spaced appropriately from the second electrode maintained at a constant voltage. A sequence of voltage pulses is applied and a pulse discharge breakdown threshold voltage is estimated for one or more gas components, from an analysis of the current-voltage characteristics. Each estimated pulse discharge breakdown threshold voltage is compared with known threshold voltages for candidate gas components to estimate whether at least one candidate gas component is present in the gas. The procedure can be repeated at higher pulse voltages to estimate a pulse discharge breakdown threshold voltage for a second component present in the gas. The CNTs in the gas sensor have a sharp (low radius of curvature) tip; they are preferably multi-wall carbon nanotubes (MWCNTs) or carbon nanofibers (CNFs), to generate high-strength electrical fields adjacent to the tips for breakdown of the gas components with lower voltage application and generation of high current. The sensor system can provide a high-sensitivity, low-power-consumption tool that is very specific for identification of one or more gas components. The sensor can be multiplexed to measure current from multiple CNT arrays for simultaneous detection of several gas components.

  5. Synthesis of Carbon Nanotubes by MWPCVD at Low Temperature

    Institute of Scientific and Technical Information of China (English)

    王升高; 汪建华; 王传新; 马志彬; 满卫东

    2002-01-01

    Growth of carbon nanotubes (CNTs) at low temperature is very important to the applications of nanotubes. In this paper, under the catalytic effect of cobalt nanoparticles supported by SiO2, CNTs were synthesized by microwave plasma chemical vapor deposition (MWPCVD)below 500℃. It demonstrates that MWPCVD can be a very efficient process for the synthesis of CNTs at low temperature.

  6. Silver decorated multiwalled carbon nanotubes and their characterization

    Science.gov (United States)

    Gahlot, Swati; Kulshrestha, Vaibhav; Shahi, V. K.

    2014-04-01

    Deposition of silver nanoparticles on functionalized multiwalled carbon nanotubes is done in the present study. To decorate silver nanoparticles on CNT walls silver nitrate (AgNO3) was used as precursor. Finally prepared nanotubes (Ag-CNT) were analyzed by TEM, XRD and FTIR for the structural and chemical characterization.

  7. A Computational Experiment on Single-Walled Carbon Nanotubes

    Science.gov (United States)

    Simpson, Scott; Lonie, David C.; Chen, Jiechen; Zurek, Eva

    2013-01-01

    A computational experiment that investigates single-walled carbon nanotubes (SWNTs) has been developed and employed in an upper-level undergraduate physical chemistry laboratory course. Computations were carried out to determine the electronic structure, radial breathing modes, and the influence of the nanotube's diameter on the…

  8. Submicrosecond-timescale readout of carbon nanotube mechanical motion

    NARCIS (Netherlands)

    Meerwaldt, H.B.; Johnston, S.R.; Van der Zant, H.S.J.; Steele, G.A.

    2013-01-01

    We report fast readout of the motion of a carbon nanotube mechanical resonator. A close-proximity high electron mobility transistor amplifier is used to increase the bandwidth of the measurement of nanotube displacements from the kHz to the MHz regime. Using an electrical detection scheme with the n

  9. Scattering of terahertz radiation from oriented carbon nanotube films

    DEFF Research Database (Denmark)

    Eichhorn, Finn; Jepsen, Peter Uhd; Schroeder, Nicholas;

    2009-01-01

    Session title: IThC-THz Interactions with Condensed Matter. We report on the use of terahertz time-domain spectroscopy to measure scattering from multi-walled carbon nanotubes aligned normal to the film plane. Measurements indicate scattering from the nanotubes is significantly stronger than...

  10. Locally addressable tunnel barriers within a carbon nanotube

    DEFF Research Database (Denmark)

    Biercuk, M.; Mason, N.; Chow, J.;

    2003-01-01

    We report the realization and characterization of independently controllable tunnel barriers within a carbon nanotube. The nanotubes are mechanically bent or kinked using an atomic force microscope, and top gates are subsequently placed near each kink. Transport measurements indicate that the kinks...

  11. Carbon Nanotubes: Printed Carbon Nanotube Electronics and Sensor Systems (Adv. Mater. 22/2016).

    Science.gov (United States)

    Chen, Kevin; Gao, Wei; Emaminejad, Sam; Kiriya, Daisuke; Ota, Hiroki; Nyein, Hnin Yin Yin; Takei, Kuniharu; Javey, Ali

    2016-06-01

    Printed electronics and sensors enable new applications ranging from low-cost disposable analytical devices to large-area sensor networks. Recent progress in printed carbon nanotube electronics in terms of materials, processing, devices, and applications is discussed on page 4397 by A. Javey and co-workers. The research challenges and opportunities regarding the processing and system-level integration are also discussed for enabling of practical applications.

  12. Carbon Nanotube Synthesis Using Coal Pyrolysis.

    Science.gov (United States)

    Moothi, Kapil; Simate, Geoffrey S; Falcon, Rosemary; Iyuke, Sunny E; Meyyappan, M

    2015-09-01

    This study investigates carbon nanotube (CNT) production from coal pyrolysis wherein the output gases are used in a chemical vapor deposition reactor. The carbon products are similar to those using commercial coal gas as feedstock, but coal is a relatively cheaper feedstock compared to high purity source gases. A Gibbs minimization model has been developed to predict the volume percentages of product gases from coal pyrolysis. Methane and carbon monoxide were the largest carbon components of the product stream and thus formed the primary source for CNT synthesis. Both the model and the observations showed that increasing the furnace temperature led to a decrease in the absolute quantities of "useful" product gases, with the optimal temperature between 400 and 500 °C. Based on the experimental data, a kinetic rate law for CNT from coal pyrolysis was derived as d[CNT]/dt = K([CO][CH4])(1/2), where K is a function of several equilibrium constants representing various reactions in the CNT formation process.

  13. Carbon nanotubes and graphene towards soft electronics

    Science.gov (United States)

    Chae, Sang Hoon; Lee, Young Hee

    2014-04-01

    Although silicon technology has been the main driving force for miniaturizing device dimensions to improve cost and performance, the current application of Si to soft electronics (flexible and stretchable electronics) is limited due to material rigidity. As a result, various prospective materials have been proposed to overcome the rigidity of conventional Si technology. In particular, nano-carbon materials such as carbon nanotubes (CNTs) and graphene are promising due to outstanding elastic properties as well as an excellent combination of electronic, optoelectronic, and thermal properties compared to conventional rigid silicon. The uniqueness of these nano-carbon materials has opened new possibilities for soft electronics, which is another technological trend in the market. This review covers the recent progress of soft electronics research based on CNTs and graphene. We discuss the strategies for soft electronics with nano-carbon materials and their preparation methods (growth and transfer techniques) to devices as well as the electrical characteristics of transparent conducting films (transparency and sheet resistance) and device performances in field effect transistor (FET) (structure, carrier type, on/off ratio, and mobility). In addition to discussing state of the art performance metrics, we also attempt to clarify trade-off issues and methods to control the trade-off on/off versus mobility). We further demonstrate accomplishments of the CNT network in flexible integrated circuits on plastic substrates that have attractive characteristics. A future research direction is also proposed to overcome current technological obstacles necessary to realize commercially feasible soft electronics.

  14. Growth of Ag nanocrystals on multiwalled carbon nanotubes and Ag-carbon nanotube interaction

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The experimental investigations on the interaction between Ag-nanocrystal particles (Ag-NCPs) and carbon nanotubes (CNTs) in Ag-nanocrystal particles/carbon nanotubes (Ag-NCPs/CNTs) hybrid structures were reported. The growth of Ag-NCPs on multiwalled carbon nanotubes (MWCNTs) was carried out by thermal evaporation deposition. High-resolution transmission electron microscopy and X-ray diffraction analyses revealed that Ag-NCPs had the crystal lattice feature of face-centered cube (fcc). The growth of Ag-NCPs on MWCNTs induced the cross-section deformation of MWCNT. The experimental results also showed that the synthesized Ag-NCPs/CNTs hybrid structure appeared as quasi-one dimensional nanowires containing the Ag-NCP/CNT hetero-junction. There was local cross-section deformation on MWCNTs at the interface of hetero-junction. These results involve the important topic about fundamental and practical studies for structure of MNCPs on CNTs and also find clues to further research of Ag nanocrystal growing on MWCNTs and related Ag-CNT interaction.

  15. Carbon nanotube--poly(3-octylthiophene) composite photovoltaic cells.

    Science.gov (United States)

    Carroll, David L; Czerw, Richard; Harrison, Benjamin

    2006-07-01

    The effects of varying nanotube loading/concentration in carbon nanotube-poly(3-octylthiophene) blends used as thin film photovoltaic cells, have been studied. The network of single walled nanotubes clearly aids in exciton separation and modifies carrier mobility within the active layer as suggested by a bulk heterojunction model. Further, modifications to the metal-polymer interface occur with the addition of nanotubes leading to variations in the observed VOC of the photovoltaic cells. Finally, the "nanocomposite" devices exhibit significant enhancements to external power conversion efficiencies, with the overall efficiency strongly dependent on device design parameters such as the addition of buffer layers.

  16. Locally addressable tunnel barriers within a carbon nanotube

    DEFF Research Database (Denmark)

    Biercuk, M.; Mason, N.; Chow, J.;

    2003-01-01

    We report the realization and characterization of independently controllable tunnel barriers within a carbon nanotube. The nanotubes are mechanically bent or kinked using an atomic force microscope, and top gates are subsequently placed near each kink. Transport measurements indicate that the kinks...... form gate-controlled tunnel barriers, and that gates placed away from the kinks have little or no effect on conductance. The overall conductance of the nanotube can be controlled by tuning the transmissions of either the kinks or the metal-nanotube contacts....

  17. Carbon nanotube based NEMS actuators and sensors

    Science.gov (United States)

    Forney, Michael; Poler, Jordan

    2011-03-01

    Single-walled carbon nanotubes (SWNTs) have been widely studied due to superior mechanical and electrical properties. We have grown vertically aligned SWNTs (VA-SWNTs) onto microcantilever (MC) arrays, which provides an architecture for novel actuators and sensors. Raman spectroscopy confirms that the CVD-grown nanotubes are SWNTs and SEM confirms aligned growth. As an actuator, this hybrid MC/VA-SWNT system can be electrostatically modulated. SWNTs are excellent electron acceptors, so we can charge up the VA-SWNT array by applying a voltage. The electrostatic repulsion among the charged SWNTs provides a surface stress that induces MC deflection. Simulation results show that a few electrons per SWNT are needed for measureable deflections, and experimental actuators are being characterized by SEM, Raman, and an AFM optical lever system. The applied voltage is sinusoidally modulated, and deflection is measured with a lock-in amplifier. These actuators could be used for nano-manipulation, release of drugs from a capsule, or nano-valves. As a sensor, this MC/VA-SWNT system offers an improved sensitivity for chemical and bio-sensing compared to surface functionalized MC-based sensors. Those sensors only have a 2D sensing surface, but a MC/VA-SWNT system has significantly more sensing surface because the VA-SWNTs extend microns off the MC surface.

  18. Microtribology of aqueous carbon nanotube dispersions

    KAUST Repository

    Kristiansen, Kai De Lange

    2011-09-23

    The tribological behavior of carbon nanotubes (CNTs) in aqueous humic acid (HA) solutions was studied using a surface forces apparatus (SFA) and shows promising lubricant additive properties. Adding CNTs to the solution changes the friction forces between two mica surfaces from "adhesion controlled" to "load controlled" friction. The coefficient of friction with either single-walled (SW) or multi-walled (MW) CNT dispersions is in the range 0.30-0.55 and is independent of the load and sliding velocity. More importantly, lateral sliding promotes a redistribution or accumulation, rather than squeezing out, of nanotubes between the surfaces. This accumulation reduced the adhesion between the surfaces (which generally causes wear/damage of the surfaces), and no wear or damage was observed during continuous shearing experiments that lasted several hours even under high loads (pressures â∼10 MPa). The frictional properties can be understood in terms of the Cobblestone Model where the friction force is related to the fraction of the adhesion energy dissipated during impacts of the nanoparticles. We also develop a simple generic model based on the van der Waals interactions between particles and surfaces to determine the relation between the dimensions of nanoparticles and their tribological properties when used as additives in oil- or water-based lubricants. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Carbon nanotubes and carbon nanotube paper%碳纳米管材料和碳纳米管纸

    Institute of Scientific and Technical Information of China (English)

    黄鸿; 黄鲲

    2015-01-01

    碳纳米管的发现,揭开了人类科技史上新的一页。本文介绍了碳纳米管、碳纳米管纸、巴基纸的特性、生产工艺技术、应用及市场前景。%The discovery of carbon nanotubes has opened a new chapter in the history of human technology. In this paper was described the characteristics of carbon nanotubes, carbon nanotube paper, technology for bucky paper production, application and market prospects.

  20. Morphology, structure and Raman scattering of carbon nanotubes produced by using mesoporous materials

    Institute of Scientific and Technical Information of China (English)

    解思深; 李文治; 王超英; 徐丽雯; 张昊; 张云; 钱露茜

    1997-01-01

    Carbon nanotubes were prepared by chemical vapor deposition (CVD) of hydrocarbon gas on various substrates.The effect of substrates on the growth,morphology and structure of carbon nanotubes were investigated.Aligned carbon nanotubes with high density and purity were achieved by CVD on mesoporous silica substrate.The Raman scattering of aligned carbon nanotubes was carried out,and the dependence of the phonon properties on the mi-crostructure of the nanotubes has been discussed.

  1. DFT Studies on Electronic Structures of Boro-Nitride-Carbon Nanotubes

    Institute of Scientific and Technical Information of China (English)

    YAN Ming; HUANG Chun-Hui

    2005-01-01

    In this paper, the configurations of Boro-Nitride-Carbon nanotubes with BNC2 composition were optimized by ROHF method. According to the density functional theory, the electronic structures of Boro-Nitride-Carbon nanotubes were calculated by DFT/ROB3LYP method. By analyzing the energy gap, density of electronic state and bonding maps of atoms, the conductive properties of Boro-Nitride-Carbon nanotubes were obtained, and compared with those of carbon nanotubes and other Boro-Nitride nanotubes.

  2. Carbon nanotubes grown on bulk materials and methods for fabrication

    Science.gov (United States)

    Menchhofer, Paul A.; Montgomery, Frederick C.; Baker, Frederick S.

    2011-11-08

    Disclosed are structures formed as bulk support media having carbon nanotubes formed therewith. The bulk support media may comprise fibers or particles and the fibers or particles may be formed from such materials as quartz, carbon, or activated carbon. Metal catalyst species are formed adjacent the surfaces of the bulk support material, and carbon nanotubes are grown adjacent the surfaces of the metal catalyst species. Methods employ metal salt solutions that may comprise iron salts such as iron chloride, aluminum salts such as aluminum chloride, or nickel salts such as nickel chloride. Carbon nanotubes may be separated from the carbon-based bulk support media and the metal catalyst species by using concentrated acids to oxidize the carbon-based bulk support media and the metal catalyst species.

  3. Process for separating metallic from semiconducting single-walled carbon nanotubes

    Science.gov (United States)

    Sun, Ya-Ping (Inventor)

    2008-01-01

    A method for separating semiconducting single-walled carbon nanotubes from metallic single-walled carbon nanotubes is disclosed. The method utilizes separation agents that preferentially associate with semiconducting nanotubes due to the electrical nature of the nanotubes. The separation agents are those that have a planar orientation, .pi.-electrons available for association with the surface of the nanotubes, and also include a soluble portion of the molecule. Following preferential association of the separation agent with the semiconducting nanotubes, the agent/nanotubes complex is soluble and can be solubilized with the solution enriched in semiconducting nanotubes while the residual solid is enriched in metallic nanotubes.

  4. Production and Characterization of Carbon Nanotubes and Nanotube-Based Composites

    Science.gov (United States)

    Nikolaev, Pavel; Arepalli, Sivaram; Holmes, William; Gorelik, Olga; Files, Brad; Scott, Carl; Santos, Beatrice; Mayeaux, Brian; Victor, Joe

    1999-01-01

    The Nobel Prize winning discovery of the Buckuball (C60) in 1985 at Rice University by a group including Dr. Richard Smalley led to the whole new class of carbon allotropes including fullerenes and nanotubes. Especially interesting from many viewpoints are single-walled carbon nanotubes, which structurally are like a single graphitic sheet wrapped around a cylinder and capped at the ends. This cylinders have diameter as small as 0.5 - 2 nm (1/100,000th the diameter of a human hair) and are as long as 0.1 - 1 mm. Nanotubes are really individual molecules and believed to be defect-free, leading to high tensile strength despite their low density. Additionally, these fibers exhibit electrical conductivity as high as copper, thermal conductivity as high as diamond, strength 100 times higher than steel at one-sixth the weight, and high strain to failure. Thus it is believed that developments in the field of nanotechnology will lead to stronger and lighter composite materials for next generation spacecraft. Lack of a bulk method of production is the primary reason nanotubes are not used widely today. Toward this goal JSC nanotube team is exploring three distinct production techniques: laser ablation, arc discharge and chemical vapor deposition (CVD, in collaboration with Rice University). In laser ablation technique high-power laser impinges on the piece of carbon containing small amount of catalyst, and nanotubes self-assemble from the resulting carbon vapor. In arc generator similar vapor is created in arc discharge between carbon electrodes with catalyst. In CVD method nanotubes grow at much lower temperature on small catalyst particles from carbon-containing feedstock gas (methane or carbon monoxide). As of now, laser ablation produces cleanest material, but mass yield is rather small. Arc discharge produces grams of material, but purity is low. CVD technique is still in baby steps, but preliminary results look promising, as well as perspective of scaling the process

  5. Fluorescence labeling of carbon nanotubes and visualization of a nanotube-protein hybrid under fluorescence microscope.

    Science.gov (United States)

    Yoshimura, Shige H; Khan, Shahbaz; Maruyama, Hiroyuki; Nakayama, Yoshikazu; Takeyasu, Kunio

    2011-04-11

    Biological applications of carbon nanotubes have been hampered by the inability to visualize them using conventional optical microscope, which is the most common tool for the observation and measurement of biological processes. Recently, a number of fluorescence labeling methods for biomolecules and various fluorescence probes have been developed and widely utilized in biological fields. Therefore, labeling carbon nanotubes with such fluorophores under physiological conditions will be highly useful in their biological applications. In this Article, we present a method to fluorescently label nanotubes by combining a detergent and a fluorophore commonly used in biological experiments. Fluorophores carrying an amino group (Texas Red hydrazide or BODIPY FL-hydrazide) were covalently attached to the hydroxyl groups of Tween 20 using carbonyldiimidazole. Fluorescence microscopy demonstrated that nanotubes were efficiently solubilized and labeled by this fluorescently labeled detergent. By using this technique, we also demonstrated multicolor fluorescence imaging of a nanotube-protein hybrid.

  6. Small Diameter Few- Walled Carbon Nanotubes: An Alternative for Single Walled nanotubes in Bulk Applications

    Institute of Scientific and Technical Information of China (English)

    Jie Liu

    2005-01-01

    @@ 1Introduction Although Single walled carbon nanotubes have shown tremendous potential in many applications due to their unique electrical and mechanical properties, the lack of a large scale synthesis method at low cost is still the main limiting factor for the realization of the full potential of this unique materials. On the other hand, multiwalled carbon nanotubes are being made in tons per year quantity and found their application in conducting plastic and other bulk applications.

  7. Exploring Carbon Nanotubes for Nanoscale Devices

    Science.gov (United States)

    Han, Jie; Dai; Anantram; Jaffe; Saini, Subhash (Technical Monitor)

    1998-01-01

    Carbon nanotubes (CNTs) are shown to promise great opportunities in nanoelectronic devices and nanoelectromechanical systems (NEMS) because of their inherent nanoscale sizes, intrinsic electric conductivities, and seamless hexagonal network architectures. I present our collaborative work with Stanford on exploring CNTs for nanodevices in this talk. The electrical property measurements suggest that metallic tubes are quantum wires. Furthermore, two and three terminal CNT junctions have been observed experimentally. We have proposed and studied CNT-based molecular switches and logic devices for future digital electronics. We also have studied CNTs based NEMS inclusing gears, cantilevers, and scanning probe microscopy tips. We investigate both chemistry and physics based aspects of the CNT NEMS. Our results suggest that CNT have ideal stiffness, vibrational frequencies, Q-factors, geometry-dependent electric conductivities, and the highest chemical and mechanical stabilities for the NEMS. The use of CNT SPM tips for nanolithography is presented for demonstration of the advantages of the CNT NEMS.

  8. Biochemical Sensors Using Carbon Nanotube Arrays

    Science.gov (United States)

    Li, Jun (Inventor); Meyyappan, Meyya (Inventor); Cassell, Alan M. (Inventor)

    2011-01-01

    Method and system for detecting presence of biomolecules in a selected subset, or in each of several selected subsets, in a fluid. Each of an array of two or more carbon nanotubes ("CNTs") is connected at a first CNT end to one or more electronics devices, each of which senses a selected electrochemical signal that is generated when a target biomolecule in the selected subset becomes attached to a functionalized second end of the CNT, which is covalently bonded with a probe molecule. This approach indicates when target biomolecules in the selected subset are present and indicates presence or absence of target biomolecules in two or more selected subsets. Alternatively, presence of absence of an analyte can be detected.

  9. Carbon-Nanotube-Based Chemical Gas Sensor

    Science.gov (United States)

    Kaul, Arunpama B.

    2010-01-01

    Conventional thermal conductivity gauges (e.g. Pirani gauges) lend themselves to applications such as leak detectors, or in gas chromatographs for identifying various gas species. However, these conventional gauges are physically large, operate at high power, and have a slow response time. A single-walled carbon-nanotube (SWNT)-based chemical sensing gauge relies on differences in thermal conductance of the respective gases surrounding the CNT as it is voltage-biased, as a means for chemical identification. Such a sensor provides benefits of significantly reduced size and compactness, fast response time, low-power operation, and inexpensive manufacturing since it can be batch-fabricated using Si integrated-circuit (IC) process technology.

  10. Electrochemical Sensors Based on Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Md. Aminur Rahman

    2009-03-01

    Full Text Available This review focuses on recent contributions in the development of the electrochemical sensors based on carbon nanotubes (CNTs. CNTs have unique mechanical and electronic properties, combined with chemical stability, and behave electrically as a metal or semiconductor, depending on their structure. For sensing applications, CNTs have many advantages such as small size with larger surface area, excellent electron transfer promoting ability when used as electrodes modifier in electrochemical reactions, and easy protein immobilization with retention of its activity for potential biosensors. CNTs play an important role in the performance of electrochemical biosensors, immunosensors, and DNA biosensors. Various methods have been developed for the design of sensors using CNTs in recent years. Herein we summarize the applications of CNTs in the construction of electrochemical sensors and biosensors along with other nanomaterials and conducting polymers.

  11. Fabrication of 3D carbon nanotube networks

    Science.gov (United States)

    Laera, Anna Maria; Mirenghi, Luciana; Schioppa, Monica; Nobile, Concetta; Capodieci, Laura; Grazia Scalone, Anna; Di Benedetto, Francesca; Tapfer, Leander

    2016-08-01

    We report on the synthesis and characterization of a hyperbranched polymer englobing single-wall carbon nanotubes (SWCNTs). This new material was obtained by using SWCNTs functionalized with carboxylic groups as starting reagent. The acid groups were firstly converted in acyl chloride moieties and afterwards were bound to hexamethylenediamine (HMDA) via formation of amide functionality. The acquired spectra of attenuated total reflectance and the analysis performed through x-ray photoelectron spectroscopy confirmed the amide bond formation. The hyperbranched polymer characterization was completed by using scanning and transmission electron microscopy, thermo-gravimetric analysis and Raman spectroscopy. The electron microscopy analyses showed the formation of an amorphous polymeric material englobing a dense network of SWCNTs without phase segregation, demonstrating that the reaction with HMDA allows a reorganization of SWCNTs in a complex three-dimensional network.

  12. Carbon nanotube-based coatings on titanium

    Indian Academy of Sciences (India)

    Elzbieta Dlugon; Wojciech Simka; Aneta Fraczek-Szczypta; Wiktor Niemiec; Jaroslaw Markowski; Marzena Szymanska; Marta Blazewicz

    2015-09-01

    This paper reports results of the modification of titanium surface with multiwalled carbon nanotubes (CNTs). The Ti samples were covered with CNTs via electrophoretic deposition (EPD) process. Prior to EPD process, CNTs were functionalized by chemical treatment. Mechanical, electrochemical and biological properties of CNT-covered Ti samples were studied and compared to those obtained for unmodified titanium surface. Atomic force microscopy was used to investigate the surface topography. To determine micromechanical characteristics of CNT-covered metallic samples indentation tests were conducted. Throughout electrochemical studies were performed in order to characterize the impact of the coating on the corrosion of titanium substrate. In vitro experiments were conducted using the human osteoblast NHOst cell line. CNT layers shielded titanium from corrosion gave the surface-enhanced biointegrative properties. Cells proliferated better on the modified surface in comparison to unmodified titanium. The deposited layer enhanced cell adhesion and spreading as compared to titanium sample.

  13. Carbon nanotubes for sustainable energy applications.

    Science.gov (United States)

    Centi, Gabriele; Perathoner, Siglinda

    2011-07-18

    The grand challenge of a sustainable production and use of energy has focused research on the nanostructure of materials. This aspect is considered of critical importance for improving the performance of advanced materials and electrodes to meet demanding expectations. Carbon nanotubes (CNTs) are the first and most-successful example of nanomaterials, and play a central role in the development of advanced solutions for sustainable energy applications. However, notwithstanding the rising scientific and technological interest in CNTs, their use is still largely based on phenomenological observations that miss the complexities of the nanostructure and characteristics of these materials. This Concept paper addresses the need for a rational design of CNTs for energy applications, based on an understanding of the key aspects to be considered for their optimization in different applications such as lithium ion batteries, supercapacitors, solar cells, and fuel cells.

  14. Sorption of indium (III) onto carbon nanotubes.

    Science.gov (United States)

    Alguacil, F J; Lopez, F A; Rodriguez, O; Martinez-Ramirez, S; Garcia-Diaz, I

    2016-08-01

    Indium has numerous applications in different industrial sectors and is not an abundant element. Therefore appropriate technology to recover this element from various process wastes is needed. This research reports high adsorption capacity of multiwalled carbon nanotubes (MWCNT) for In(III). The effects of pH, kinetics, isotherms and adsorption mechanism of MWCNT on In(III) adsorption were investigated and discussed in detail. The pH increases improves the adsorption capacity for In(III). The Langmuir adsorption model is the best fit with the experimental data. For the kinetic study, the adsorption onto MWCNT could be fitted to pseudo second-order. The adsorption of indium(III) can be described to a mechanism which consists of a film diffusion controlled process. Metal desorption can be achieved with acidic solutions.

  15. Analysis of ionic conductance of carbon nanotubes

    CERN Document Server

    Biesheuvel, P M

    2016-01-01

    We use space-charge (SC) theory (also called the capillary pore model) to describe the ionic conductance, $G$, of charged carbon nanotubes (CNTs). Based on the reversible adsorption of hydroxyl ions to CNT pore walls, we use a Langmuir isotherm for surface ionization and make calculations as function of pore size, salt concentration $c$, and pH. Using realistic values for surface site density and pK, SC theory well describes published experimentally data on the conductance of CNTs. At extremely low salt concentration, when the electric potential becomes uniform across the pore, and surface ionization is low, we derive the scaling $G\\sim \\sqrt{c}$, while for realistic salt concentrations, SC theory does not lead to a simple power law for $G(c)$.

  16. Fabrication of Microscale Carbon Nanotube Fibers

    Directory of Open Access Journals (Sweden)

    Gengzhi Sun

    2012-01-01

    Full Text Available Carbon nanotubes (CNTs have excellent mechanical, chemical, and electronic properties, but realizing these excellences in practical applications needs to assemble individual CNTs into larger-scale products. Recently, CNT fibers demonstrate the potential of retaining CNT's superior properties at macroscale level. High-performance CNT fibers have been widely obtained by several fabrication approaches. Here in this paper, we review several key spinning techniques including surfactant-based coagulation spinning, liquid-crystal-based solution spinning, spinning from vertical-aligned CNT arrays, and spinning from CNT aerogel. The method, principle, limitations, and recent progress of each technique have been addressed, and the fiber properties and their dependences on spinning parameters are also discussed.

  17. Thermal Conductivity of Carbon Nanotube Composite Films

    Science.gov (United States)

    Ngo, Quoc; Cruden, Brett A.; Cassell, Alan M.; Walker, Megan D.; Koehne, Jessica E.; Meyyappan, M.; Li, Jun; Yang, Cary Y.

    2004-01-01

    State-of-the-art ICs for microprocessors routinely dissipate power densities on the order of 50 W/sq cm. This large power is due to the localized heating of ICs operating at high frequencies, and must be managed for future high-frequency microelectronic applications. Our approach involves finding new and efficient thermally conductive materials. Exploiting carbon nanotube (CNT) films and composites for their superior axial thermal conductance properties has the potential for such an application requiring efficient heat transfer. In this work, we present thermal contact resistance measurement results for CNT and CNT-Cu composite films. It is shown that Cu-filled CNT arrays enhance thermal conductance when compared to as-grown CNT arrays. Furthermore, the CNT-Cu composite material provides a mechanically robust alternative to current IC packaging technology.

  18. Carbon Nanotube Templated Asembly of Protein

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Guodong; Lin, Yuehe

    2006-04-01

    This paper describes a novel general strategy for fabricating protein-polyion multilayers by electrostatic layer-by-layer (LBL) self-assembly on a carbon nanotube (CNT) template. Such a noncovalent functionalization method is important for preserving the activity of biomolecules and the mechanical and electrical properties of CNTs. Glucose oxidase and poly (diallydimethylammonium) chloride polymer were used as a model to investigate the LBL process on a CNT template. High-resolution transmission electron microscopy and electrochemical characterization confirm the formation of LBL nanostructures on carboxyl functionalized CNTs. We have also demonstrated the applications of these nanoshell bioreactors to the direct electrochemistry of proteins and biosensing. This strategy can be applied to assemble other biological molecules, such as antibodies, antigens, and DNA, for wide bioassay applications.

  19. Electrochemical potential at the interface between carbon nanotubes and electrolyte

    Institute of Scientific and Technical Information of China (English)

    LU Jian-wei; WANG Wan-lu; WU Zi-hua; WANG Yong-tian

    2004-01-01

    The dependences of electrochemical potential at the interface between carbon nanotubes and electrolyte upon temperature and electrolyte concentration are studied. Carbon nanotubes were synthesized by hot filament chemical vapor deposition with Si as the substrate. Four substances were tested: NaCl solution, KCl solution, water and alcohol. It is found that for NaCl and KCl solutions, at the interface, there is a large electrochemical potential which increases with temperature and is larger for an electrolyte of higher concentration. There is a significant field effect of carbon nanotubes with electrolyte as the gate,and the effect depends on the ionizability of the electrolyte. Such physicochemical property invests carbon nanotube a potential application in nanoelectronics.

  20. Radical scavenging reaction kinetics with multiwalled carbon nanotubes

    NARCIS (Netherlands)

    Tsuruoka, Shuji; Matsumoto, Hidetoshi; Koyama, Kenichi; Akiba, Eiji; Yanagisawa, Takashi; Cassee, Flemming R.; Saito, Naoto; Usui, Yuki; Kobayashi, Shinsuke; Porter, Dale W.; Castranova, Vincent; Endo, Morinobu

    2015-01-01

    Progress in the development of carbon nanotubes (CNTs) has stimulated great interest among industries providing new applications. Meanwhile, toxicological evaluations on nanomaterials are advancing leading to a predictive exposure limit for CNTs, which implies the possibility of designing safer CNTs

  1. Polymerization Initiated at the Sidewalls of Carbon Nanotubes

    Science.gov (United States)

    Tour, James M.; Hudson, Jared L.

    2011-01-01

    A process has been developed for growing polymer chains via anionic, cationic, or radical polymerization from the side walls of functionalized carbon nanotubes, which will facilitate greater dispersion in polymer matrices, and will greatly enhance reinforcement ability in polymeric material.

  2. Aligned carbon nanotubes physics, concepts, fabrication and devices

    CERN Document Server

    Ren, Zhifeng; Wang, Yang

    2012-01-01

    This book surveys the physics and fabrication of carbon nanotubes and their applications in optics, electronics, chemistry and biotechnology. The text illustrates major fabrication methods in detail, particularly the most widely used PECVD growth techniques.

  3. Selective growth of carbon nanotube on silicon substrates

    Institute of Scientific and Technical Information of China (English)

    ZOU Xiao-ping; H. ABE; T. SHIMIZU; A. ANDO; H. TOKUMOT; ZHU Shen-ming; ZHOU Hao-shen

    2006-01-01

    The carbon nanotube (CNT) growth of iron oxide-deposited trench-patterns and the locally-ordered CNT arrays on silicon substrate were achieved by simple thermal chemical vapor deposition(STCVD) of ethanol vapor. The CNTs were uniformly synthesized with good selectivity on trench-patterned silicon substrates. This fabrication process is compatible with currently used semiconductor-processing technologies,and the carbon-nanotube fabrication process can be widely applied for the development of electronic devices using carbon-nanotube field emitters as cold cathodes and can revolutionize the area of field-emitting electronic devices. The site-selective growth of CNT from an iron oxide nanoparticle catalyst patterned were also achieved by drying-mediated self-assembly technique. The present method offers a simple and cost-effective method to grow carbon nanotubes with self-assembled patterns.

  4. Multiwalled Carbon Nanotube Deposition on Model Environmental Surfaces

    Science.gov (United States)

    Deposition of multiwalled carbon nanotubes (MWNTs) on model environmental surfaces was investigated using a quartz crystal microbalance with dissipation monitoring (QCM-D). Deposition behaviors of MWNTs on positively and negatively charged surfaces were in good agreement with Der...

  5. High-Conductance Thermal Interfaces Based on Carbon Nanotubes Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to develop a novel thermal interface material (TIM) that is based on an array of vertical carbon nanotubes (CNTs) for high heat flux applications. For...

  6. Real-Time Observation of Cell and Carbon Nanotube Interactions

    Science.gov (United States)

    Chen, Michelle; Broman, Melanie; Mathews, Claire; McPherson, Eric

    2014-03-01

    Carbon nanotubes have been widely researched for disease diagnosis and drug delivery applications. However, its impact on biological systems is yet to be sufficiently understood. We studied optical imaging of Chinese hamster ovarian (CHO) cells exposed to various carbon nanotubes concentrations at various time points. The cell stress due to carbon nanotubes exposure is accessed via morphological changes of the CHO cells. Data showed that cell death increases with increasing carbon nanotube concentration and time exposure. To continuously view such changes of any one individual cell, we constructed an optically transparent miniaturized incubator that fits on a microscope stage. This specific incubator is able to maintain desirable temperature, humidity, and CO2 concentration to allow proper cell growth. Such incubator can be used to track real-time interactions of any cells and nanomaterials for future data collection.

  7. Carbon nanotubes for interconnects process, design and applications

    CERN Document Server

    Dijon, Jean; Maffucci, Antonio

    2017-01-01

    This book provides a single-source reference on the use of carbon nanotubes (CNTs) as interconnect material for horizontal, on-chip and 3D interconnects. The authors demonstrate the uses of bundles of CNTs, as innovative conducting material to fabricate interconnect through-silicon vias (TSVs), in order to improve the performance, reliability and integration of 3D integrated circuits (ICs). This book will be first to provide a coherent overview of exploiting carbon nanotubes for 3D interconnects covering aspects from processing, modeling, simulation, characterization and applications. Coverage also includes a thorough presentation of the application of CNTs as horizontal on-chip interconnects which can potentially revolutionize the nanoelectronics industry. This book is a must-read for anyone interested in the state-of-the-art on exploiting carbon nanotubes for interconnects for both 2D and 3D integrated circuits. Provides a single-source reference on carbon nanotubes for interconnect applications; Includes c...

  8. Conformal Carbon Nanotubes for Stray Light Suppression Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Our objective is to apply CVD and non-CVD carbon nanotubes to complex shapes that numerous scientists have requested for stray light control.  Currently, CVD...

  9. Synthesis of carbon nanotubes with Ni/CNTs catalyst

    Institute of Scientific and Technical Information of China (English)

    李春华; 姚可夫; 阮殿波; 梁吉; 徐才录; 吴德海

    2003-01-01

    Carbon nanotubes (CNTs), owing to their large specific area, good chemical stability and modifiable surface properties after acidic or basic treatment, can be used as catalytic support materials. In this paper, the activities and selectivities of two catalysts, i. e. Ni catalyst supported by carbon nanotubes (Ni/CNTs) and that supported by diatomite (Ni/SiO2), are compared. It is found that the quality of the carbon nanotubes synthesized by the two catalysts is similar, but the yield of the former is 1.5 times higher than that of the latter. The excellent performance of the Ni/CNTs catalyst should be ascribed to the larger specific surface area and proper pore distribution and the structure of the carbon nanotube support.

  10. Piezoresistive Effect of Doped carbon Nanotube/Cellulose Films

    Institute of Scientific and Technical Information of China (English)

    王万录; 廖克俊; 李勇; 王永田

    2003-01-01

    The strain-induced resistance changes in iodine-doped and undoped carbon nanotube films were investigated by a three-point bending test. Carbon nanotubes were fabricated by hot filament chemical vapour deposition. The experimental results showed that there has a striking piezoresistive effect in carbon nanotube films. The gauge factor for I-doped and undoped carbon nanotube films under 500 microstrain was about 125 and 65 respectively at room temperature, exceeding that of polycrystalline silicon (30) at 35℃. The origin of the piezoresistivity in the films may be ascribed to a strain-induced change in the band gap for the doped tubes and to the intertube contact resistance for the undoped tubes.

  11. Controlling electrical percolation in multicomponent carbon nanotube dispersions

    NARCIS (Netherlands)

    Kyrylyuk, A.V.; Hermant, M. -C; Schilling, T.; Klumperman, B.; van der Schoot, P. P. A. M.

    2011-01-01

    Carbon nanotube reinforced polymeric composites can have favourable electrical properties, which make them useful for applications such as flat-panel displays and photovoltaic devices. However, using aqueous dispersions to fabricate composites with specific physical properties requires that the proc

  12. Carbon nanotube-based separation columns for microchip electrochromatography

    DEFF Research Database (Denmark)

    Mogensen, K. B.; Delacourt, B.; Kutter, Jörg P.

    2015-01-01

    the fabrication and operation protocols for devices with microfabricated carbon nanotube stationary phases for reversephase chromatography. In this protocol, the lithographically defined stationary phase is fabricated in the channel before bonding of a lid, thereby circumventing the difficult packaging procedures...

  13. Hydrogen isotherms in palladium loaded carbon nanotubes and activated carbons

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, M. T.; Anson, A.; Lafuente, E.; Urriolabeitia, E.; Navarro, R.; Benito, A. M.; Maser, W. K.

    2005-07-01

    Session 5a In order to increase the hydrogen sorption capacity of carbon materials, a sample of single-wall carbon nanotubes (SWNTs) and the activated carbon MAXSORB have been loaded with palladium nanoparticles. While carbon materials adsorb hydrogen due to physical interactions, palladium can capture hydrogen into the bulk structure or chemically react to form hydrides. Experiental SWNTs have been synthesized in an electric arc reactor, using Ni and Y as catalysts in a 660 mbar He atmosphere. MAXSORB is a commercial activated carbon obtained from petroleum coke through a chemical treatment with KOH. Palladium has been deposited over the carbon support by means of a reflux method in a solution of an organometallic complex. Different samples have been prepared depending on the weight ratio (Carbon material / Pd) in the original reactants. The effectiveness of the deposition method has been examined by means of X-ray diffraction (XRD), induction coupled plasma spectrometry (ICPS) and transmission electron microscopy (TEM). The volumetric system Autosorb-1 from Quantachrome Instruments has been used to obtain the nitrogen adsorption isotherms at 77 K for all the materials. The hydrogen isotherms at 77 K and room temperature and up to 800 torr have also been obtained in the Autosorb-1. The BET specific surface area and the micropore volume have been calculated from the nitrogen adsorption data. High pressure hydrogen isotherms up to 90 bar have been carried out at room temperature in a VTI system provided with a Rubotherm microbalance. (Author)

  14. Synthesis of carbon nanotubes using natural carbon precursor: Castor oil

    Science.gov (United States)

    Raziah, A. Z.; Junizah, A. R.; Saifuddin, N.

    2012-09-01

    Castor oil has long been an article of commerce due to its versatility as it is widely used as a starting material for many industrial chemical products because of its unique structure. In this study, carbon nanotubes has been synthesized by thermal decomposition of castor oil in nitrogen atmosphere at 300-400δC using custom-made microwave processing unit. The precursor material was catalyzed by iron clusters originating from the addition of ferrocene. The morphology and characterization of the CNTs were studied and discussed by transmission electron microscopy (TEM).

  15. A concise review of carbon nanotube's toxicology

    Directory of Open Access Journals (Sweden)

    Seyed Yazdan Madani

    2013-12-01

    Full Text Available Carbon nanotubes can be either single-walled or multi-walled, each of which is known to have a different electron arrangement and as a result have different properties. However, the shared unique properties of both types of carbon nanotubes (CNT allow for their potential use in various biomedical devices and therapies. Some of the most common properties of these materials include the ability to absorb near-infra-red light and generate heat, the ability to deliver drugs in a cellular environment, their light weight, and chemical stability. These properties have encouraged scientists to further investigate CNTs as a tool for thermal treatment of cancer and drug delivery agents. Various promising data have so far been obtained about the usage of CNTs for cancer treatment; however, toxicity of pure CNTs represents a major challenge for clinical application. Various techniques both in vivo and in in vitro have been conducted by a number of different research groups to establish the factors which have a direct effect on CNT-mediated cytotoxicity. The main analysis techniques include using Alamar blue, MTT, and Trypan blue assays. Successful interpretation of these results is difficult because the CNTs can significantly disrupt the emission of the certain particles, which these assays detect. In contrast, in vivo studies allow for the measurement of toxicity and pathology caused by CNTs on an organismal level. Despite the drawbacks of in vitro studies, they have been invaluable in identifying important toxicity factors, such as size, shape, purity, and functionalisation, the latter of which can attenuate CNT toxicity.

  16. Single-Walled Carbon Nanotubes for Flexible Electronics and Sensors

    Institute of Scientific and Technical Information of China (English)

    Xiuyun SUN; Yugang SUN

    2008-01-01

    This article reviews the use of electronic quality single-walled carbon nanotubes grown via chemical vapor deposition (CVD) approaches at high temperatures as building blocks for fabricating flexible field-effect devices, such as thin-film transistors (TFTs) and chemical sensors. Dry transfer printing technique is developed for forming films of CVD nanotubes on low-temperature plastic substrates. Examples of TFTs with the use of nanotubes and thin dielectrics and hydrogen sensors with the use of nanotubes decorated with palladium nanoparticles are discussed in detail to demonstrate the promising potentiality of single-walled carbon nanotubes for building high performance flexible devices, which can find applications where traditional devices on rigid substrates are not suitable.

  17. Simulation of Carbon Nanotube Welding through Ar bombardment

    CERN Document Server

    Kucukkal, Mustafa U

    2014-01-01

    Single-walled carbon nanotubes show promise as nanoscale transistors, for nanocomputing applications. This use will require appropriate methods for creating electrical connections between distinct nanotubes, analogous to welding of metallic wires at larger length scales, but methods for performing nanoscale chemical welding are not yet sufficiently understood. This study examined the effect of Ar bombardment on the junction of two crossed single-walled carbon nanotubes, to understand the value and limitations of this method for generating connections between nanotubes. A geometric criterion was used to assess the quality of the junctions formed, with the goal of identifying the most productive conditions for experimental ion bombardment. In particular, the effects of nanotube chirality, Ar impact kinetic energy, impact particle flux and fluence, and annealing temperature were considered. The most productive bombardment conditions, leading to the most crosslinking of the tubes with the smallest loss of graphit...

  18. Engineering of Carbon Nanotube Actuators and Tools for Their Characterization

    Science.gov (United States)

    Kozlov, Mikhail; Chang, Heping; Cui, Changxing; Liu, Lo-Min; Morris, Bob; Spinks, Geoff; Khayrullin, Ilyas; Zakhidov, Anvar; Iqbal, Zafar; Baughman, Ray

    2000-03-01

    We report comparative data on electromechanical response as a function of voltage for carbon actuators based on single-wall and multi-wall nanotubes, graphite and nanotube-polymer composites. The measurements were carried out in aqueous NaCl electrolyte, under variable load, in broad voltage and temperature ranges. A specially designed tensile tester provided isometric conditions for sample characterization. Data on stress-strain generation, elastic constants, and thermal expansion was obtained from our apparatus. Measurements show that isometric stress generation in an actuator based on low-surface- area graphite is less than 0.01 MPa, whereas for single-wall nanotubes this stress readily exceeds 0.7 MPa. Experimental data are compared with predictions for the dimensional changes in carbon nanotubes caused by charge injection and temperature variation. Tensile, cantilever and helical actuation mechanisms in single-wall nanotubes are discussed.

  19. Membranes with functionalized carbon nanotube pores for selective transport

    Science.gov (United States)

    Bakajin, Olgica; Noy, Aleksandr; Fornasiero, Francesco; Park, Hyung Gyu; Holt, Jason K; Kim, Sangil

    2015-01-27

    Provided herein composition and methods for nanoporous membranes comprising single walled, double walled, or multi-walled carbon nanotubes embedded in a matrix material. Average pore size of the carbon nanotube can be 6 nm or less. These membranes are a robust platform for the study of confined molecular transport, with applications in liquid and gas separations and chemical sensing including desalination, dialysis, and fabric formation.

  20. Production of single-walled carbon nanotube grids

    Science.gov (United States)

    Hauge, Robert H; Xu, Ya-Qiong; Pheasant, Sean

    2013-12-03

    A method of forming a nanotube grid includes placing a plurality of catalyst nanoparticles on a grid framework, contacting the catalyst nanoparticles with a gas mixture that includes hydrogen and a carbon source in a reaction chamber, forming an activated gas from the gas mixture, heating the grid framework and activated gas, and controlling a growth time to generate a single-wall carbon nanotube array radially about the grid framework. A filter membrane may be produced by this method.

  1. Methods for selective functionalization and separation of carbon nanotubes

    Science.gov (United States)

    Strano, Michael S. (Inventor); Usrey, Monica (Inventor); Barone, Paul (Inventor); Dyke, Christopher A. (Inventor); Tour, James M. (Inventor); Kittrell, W. Carter (Inventor); Hauge, Robert H (Inventor); Smalley, Richard E. (Inventor); Marek, legal representative, Irene Marie (Inventor)

    2011-01-01

    The present invention is directed toward methods of selectively functionalizing carbon nanotubes of a specific type or range of types, based on their electronic properties, using diazonium chemistry. The present invention is also directed toward methods of separating carbon nanotubes into populations of specific types or range(s) of types via selective functionalization and electrophoresis, and also to the novel compositions generated by such separations.

  2. Continuous Production of Carbon Nanotubes by Using Moving Bed Reactor

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    High-quality carbon nanotubes were continuously produced by using moving bed reactor. The studies of scanning electron microscopy and transmission electron microscopy reveal their homogeneity both in inner (~ 10 nm) and outer diameter (20-40 nm) of the tubes. The studies of X-ray photoelectron spectroscopy and the oxidation of carbon nanotubes in air demonstrate that the tubes have good graphitic degree.

  3. Controllable method for fabricating single-wall carbon nanotube tips

    Science.gov (United States)

    Zhang, Y.; Iijima, S.

    2000-08-01

    Single-wall carbon nanotubes (SWCNTs) were abruptly cut with a niobium substrate after a heating process in an ultrahigh vacuum transmission electron microscope. The cutting was attributed to a break of weakly bonded interface between carbon nanotubes and niobium carbide that formed as a product of a solid-phase reaction. This effect provided a controllable method for preparing well-defined SWCNT tips in future field-emission applications.

  4. Functionalized Carbon Nanotube-Polymer Composites and Interactions with Radiation

    Science.gov (United States)

    Barrera, Enrique V. (Inventor); Wilkins, Richard (Inventor); Shofner, Meisha (Inventor); Pulikkathara, Merlyn X. (Inventor); Vaidyanathan, Ranjii (Inventor)

    2014-01-01

    The present invention involves the interaction of radiation with functionalized carbon nanotubes that have been incorporated into various host materials, particularly polymeric ones. The present invention is directed to chemistries, methods, and apparatuses which exploit this type of radiation interaction, and to the materials which result from such interactions. The present invention is also directed toward the time dependent behavior of functionalized carbon nanotubes in such composite systems.

  5. Vertically aligned multiwalled carbon nanotubes as electronic interconnects.

    OpenAIRE

    Gopee, Vimal C.

    2017-01-01

    The drive for miniaturisation of electronic circuits provides new materials challenges for the electronics industry. Indeed, the continued downscaling of transistor dimensions, described by Moore’s Law, has led to a race to find suitable replacements for current interconnect materials to replace copper. Carbon nanotubes have been studied as a suitable replacement for copper due to its superior electrical, thermal and mechanical properties. One of the advantages of using carbon nanotubes is th...

  6. Adsorption of multimeric T cell antigens on carbon nanotubes

    DEFF Research Database (Denmark)

    Fadel, Tarek R; Li, Nan; Shah, Smith;

    2013-01-01

    Antigen-specific activation of cytotoxic T cells can be enhanced up to three-fold more than soluble controls when using functionalized bundled carbon nanotube substrates ((b) CNTs). To overcome the denaturing effects of direct adsorption on (b) CNTs, a simple but robust method is demonstrated...... to stabilize the T cell stimulus on carbon nanotube substrates through non-covalent attachment of the linker neutravidin....

  7. Carbon Nanotube Electrodes for Effective Interfacing with Retinal Tissue

    OpenAIRE

    Shoval, Asaf; Adams, Christopher; David-Pur, Moshe; Shein, Mark; Hanein, Yael; Sernagor, Evelyne

    2009-01-01

    We have investigated the use of carbon nanotube coated microelectrodes as an interface material for retinal recording and stimulation applications. Test devices were micro-fabricated and consisted of 60, 30 μm diameter electrodes at spacing of 200 μm. These electrodes were coated via chemical vapor deposition of carbon nanotubes, resulting in conducting, three dimensional surfaces with a high interfacial area. These attributes are important both for the quality of the cell-surface coupling as...

  8. One dimensional models of excitons in carbon nanotubes

    DEFF Research Database (Denmark)

    Cornean, Horia Decebal; Duclos, P.; Pedersen, Thomas Garm

    Excitons in carbon nanotubes may be modeled by two oppositely charged particles living on the surface of a cylinder. We derive three one dimensional effective Hamiltonians which become exact as the radius of the cylinder vanishes. Two of them are solvable.......Excitons in carbon nanotubes may be modeled by two oppositely charged particles living on the surface of a cylinder. We derive three one dimensional effective Hamiltonians which become exact as the radius of the cylinder vanishes. Two of them are solvable....

  9. Carbon Nanotube/Graphene Supercapacitors Containing Manganese Oxide Nanoparticles

    Science.gov (United States)

    2012-12-01

    electrolytes : 0.5 M K2SO4, 1 M sodium chloride (NaCl), and 1 M calcium chloride (CaCl2). The qualitative CV behavior of the three electrolytes can be seen...Carbon Nanotube/ Graphene Supercapacitors Containing Manganese Oxide Nanoparticles by Matthew Ervin, Vinay Raju, Mary Hendrickson, and...Laboratory Adelphi, MD 20783-1197 ARL-TR-6289 December 2012 Carbon Nanotube/ Graphene Supercapacitors Containing Manganese Oxide

  10. Exposure to Carbon Nanotube Material: Assessment of Nanotube Cytotoxicity Using Human Keratinocyte Cells

    Science.gov (United States)

    Shvedova, Anna A.; Castranova, Vincent; Kisin, Elena R.; Schwegler-Berry, Diane; Murray, Ashley R.; Gandelsman, Vadim Z.; Maynard, Andrew; Baron, Paul

    2003-01-01

    Carbon nanotubes are new members of carbon allotropes similar to fullerenes and graphite. Because of their unique electrical, mechanical, and thermal properties, carbon nanotubes are important for novel applications in the electronics, aerospace, and computer industries. Exposure to graphite and carbon materials has been associated with increased incidence of skin diseases, such as carbon fiber dermatitis, hyperkeratosis, and naevi. We investigated adverse effects of single-wall carbon nanotubes (SWCNT) using a cell culture of immortalized human epidermal keratinocytes (HaCaT). After 18 h of exposure of HaCaT to SWCNT, oxidative stress and cellular toxicity were indicated by formation of free radicals, accumulation of peroxidative products, antioxidant depletion, and loss of cell viability. Exposure to SWCNT also resulted in ultrastructural and morphological changes in cultured skin cells. These data indicate that dermal exposure to unrefined SWCNT may lead to dermal toxicity due to accelerated oxidative stress in the skin of exposed workers.

  11. The growth of carbon nanotubes on montmorillonite and zeolite (clinoptilolite)

    Energy Technology Data Exchange (ETDEWEB)

    Kadlecikova, M. [Department of Microelectronics, Faculty of Electrical Engineering and Information Technology, Slovak University of Technology, Ilkovicova 3, 812 19 Bratislava (Slovakia); Breza, J. [Department of Microelectronics, Faculty of Electrical Engineering and Information Technology, Slovak University of Technology, Ilkovicova 3, 812 19 Bratislava (Slovakia)], E-mail: juraj.breza@stuba.sk; Jesenak, K.; Pastorkova, K.; Luptakova, V. [Department of Inorganic Chemistry, Faculty of Natural Sciences, Comenius University, Mlynska Dolina, 842 15 Bratislava (Slovakia); Kolmacka, M.; Vojackova, A. [Department of Microelectronics, Faculty of Electrical Engineering and Information Technology, Slovak University of Technology, Ilkovicova 3, 812 19 Bratislava (Slovakia); Michalka, M. [International Laser Centre, Ilkovicova 3, 812 19 Bratislava (Slovakia); Vavra, I. [Institute of Electrical Engineering, Slovak Academy of Sciences, Dubravska Cesta 9, 841 04 Bratislava (Slovakia); Krizanova, Z. [Department of Microelectronics, Faculty of Electrical Engineering and Information Technology, Slovak University of Technology, Ilkovicova 3, 812 19 Bratislava (Slovakia)

    2008-06-15

    Synthesis of carbon nanotubes described in the present work is based on activation of methane in a hot filament CVD reactor and subsequent creation of nanostructures on a catalyst pre-treated polished surface of silicon. An essential step of the synthesis is the use of natural minerals as catalysts. We have studied the catalyst parameters, the way of its application and the amount of Fe{sup 3+} cations on the surface of aluminosilicates on the quality of the grown nanotube layers. The growth of carbon nanotubes catalyzed by montmorillonite and zeolite (clinoptilolite) was confirmed by scanning electron microscopy and Raman spectroscopy.

  12. The growth of carbon nanotubes on montmorillonite and zeolite (clinoptilolite)

    Science.gov (United States)

    Kadlečíková, M.; Breza, J.; Jesenák, K.; Pastorková, K.; Luptáková, V.; Kolmačka, M.; Vojačková, A.; Michalka, M.; Vávra, I.; Križanová, Z.

    2008-06-01

    Synthesis of carbon nanotubes described in the present work is based on activation of methane in a hot filament CVD reactor and subsequent creation of nanostructures on a catalyst pre-treated polished surface of silicon. An essential step of the synthesis is the use of natural minerals as catalysts. We have studied the catalyst parameters, the way of its application and the amount of Fe 3+ cations on the surface of aluminosilicates on the quality of the grown nanotube layers. The growth of carbon nanotubes catalyzed by montmorillonite and zeolite (clinoptilolite) was confirmed by scanning electron microscopy and Raman spectroscopy.

  13. Effect of temperature on deformation of carbon nanotube under compression

    Institute of Scientific and Technical Information of China (English)

    王宇; 倪向贵; 王秀喜; 吴恒安

    2003-01-01

    The mechanical behaviour of carbon nanotubes is one of the basic research fields on the nanotube composites and nano machinery.Molecular dynamics is an effective way for investigating the behaviour of nano structure.The compression deformation of carbon nanotubes(CNTs)under different temperature is simulated,by using the Tersoff-Brenner potential to describe the interactions in CNTs.The results show that thermal fluctuations may induce the strained CNT to overcome the local energy barrier and develop the plastic deformation.

  14. Polymer cantilever platform for dielectrophoretic assembly of carbon nanotubes

    DEFF Research Database (Denmark)

    Johansson, Alicia; Calleja, M.; Dimaki, Maria;

    2004-01-01

    A polymer cantilever platform for dielectrophoretic assembly of carbon nanotubes has been designed and realized. Multi-walled carbon nanotubes from aqueous solution have been assembled between two metal electrodes that are separated by 2 mu m and embedded in the polymer cantilever. The entire chip......, except for the metallic electrodes and wiring, was fabricated in the photoresist SU-8. SU-8 allows for an inexpensive, flexible and fast fabrication method, and the cantilever platform provides a hydrophobic surface that should be well suited for nanotube assembly. The device can be integrated in a micro...

  15. Neutron activation study of gold-decorated singlewall carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Goncalves, Rafael G.F.; Oliveira, Arno H. de [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Engenharia Nuclear; Ladeira, Luiz O.; Lacerda, Rodrigo G.; Oliveira, Sergio de; Pinheiro, Mauricio V.B. [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Fisica; Ferreira, Andrea V. [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2007-07-01

    Single-wall carbon nanotubes (SWNT) were synthesized by arc discharge technique of doped graphite electrodes and purified by burning the amorphous carbon and removing the metals with hydrochloric acid (HCl). The nanotubes were also functionalized with carboxyl groups (-COOH) by ultrasonification with nitric (HNO{sub 3}) and sulfuric (H{sub 2}SO{sub 4}) acids. The nanotubes were then decorated with gold by reducing chloroauric acid (HAuCl{sub 4}) with UV and hydrazine (N{sub 2}H{sub 4}). Atomic Force Microscope (AFM) images confirmed the decoration with the hydrazine route. The gold concentration in the samples was analyzed by neutron activation analysis. (author)

  16. In situ Diagnostics During Carbon Nanotube Production by Laser Ablation

    Science.gov (United States)

    Arepalli, Sivaram

    1999-01-01

    The preliminary results of spectral analysis of the reaction zone during the carbon nanotube production by laser ablation method indicate synergetic dependence on dual laser setup. The emission spectra recorded from different regions of the laser ablated plume at different delay times from the laser pulses are used to map the temperatures of C2 and C3. These are compared with Laser Induced Fluorescence (LIF) spectra also obtained during production to model the growth mechanism of carbon nanotubes. Experiments conducted to correlate the spectral features with nanotube yields as a function of different production parameters will be discussed.

  17. Obtaining New Dental Materials Reinforced with Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    I.V. Zaporotskova

    2014-07-01

    Full Text Available The article seeks to explore the change of strength properties of composite polymer material on the basis of fast-hardening dental plastic "Carbogen", when reinforcing its coal-native nanotubes. Were discussed peculiarities of composition of Carboante, ways of creation of polymeric composition deposits by doping their carbon nanotubes, the results of measuring the strength characteristic characteristics obtained new polymer materials. On the basis of the analysis of the practical and the theoretical-sky research, conclusions were drawn on the feasibility of a new filling material with the use of carbon nanotubes with unique strength characteristics and use of their in dentistry.

  18. Dielectrophoretic manipulation of fluorescing single-walled carbon nanotubes.

    Science.gov (United States)

    Mureau, Natacha; Mendoza, Ernest; Silva, S Ravi P

    2007-05-01

    We investigate the behavior of fluorescing single-walled carbon nanotubes (SWCNTs) under dielectrophoretic conditions and demonstrate their collection with fluorescence microscopy. SWCNTs are dispersed in water with the aid of a nonionic surfactant, Triton X-100, and labeled through noncovalent binding with the dye 3,3'-dihexyloxacarbocyanine iodide (diOC(6)). The chromophore's affinity to the SWCNTs is due to pi-stacking interactions. Carbon nanotube (CNT) localization is clearly identified on the fluorescence images, showing that the nanotubes concentrate between the electrodes and align along the electric field lines.

  19. Molecular Dynamics Simulations of Laser Powered Carbon Nanotube Gears

    Science.gov (United States)

    Srivastava, Deepak; Globus, Al; Han, Jie; Chancellor, Marisa K. (Technical Monitor)

    1997-01-01

    Dynamics of laser powered carbon nanotube gears is investigated by molecular dynamics simulations with Brenner's hydrocarbon potential. We find that when the frequency of the laser electric field is much less than the intrinsic frequency of the carbon nanotube, the tube exhibits an oscillatory pendulam behavior. However, a unidirectional rotation of the gear with oscillating frequency is observed under conditions of resonance between the laser field and intrinsic gear frequencies. The operating conditions for stable rotations of the nanotube gears, powered by laser electric fields are explored, in these simulations.

  20. Thermophoretic Motion of Water Nanodroplets confined inside Carbon Nanotubes

    DEFF Research Database (Denmark)

    Zambrano, Harvey A; Walther, Jens Honore; Koumoutsakos, Petros

    2009-01-01

    We study the thermophoretic motion of water nanodroplets confined inside carbon nanotubes using molecular dynamics simulations. We find that the nanodroplets move in the direction opposite the imposed thermal gradient with a terminal velocity that is linearly proportional to the gradient. The tra......We study the thermophoretic motion of water nanodroplets confined inside carbon nanotubes using molecular dynamics simulations. We find that the nanodroplets move in the direction opposite the imposed thermal gradient with a terminal velocity that is linearly proportional to the gradient....... The translational motion is associated with a solid body rotation of the water nanodroplet coinciding with the helical symmetry of the carbon nanotube. The thermal diffusion displays a weak dependence on the wetting of the water-carbon nanotube interface. We introduce the use of the Moment Scaling Spectrum (MSS......) in order to determine the characteristics of the motion of the nanoparticles inside the carbon nanotube. The MSS indicates that affinity of the nanodroplet with the walls of the carbon nanotubes is important for the isothermal diffusion, and hence for the Soret coefficient of the system....

  1. Nonlinear buckling analyses of a small-radius carbon nanotube

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Ning, E-mail: liuxiao@ase.buaa.edu.cn; Li, Min; Jia, Jiao [School of Aeronautic Science and Engineering, Beihang University, Beijing 100091 (China); Wang, Yong-Gang [Department of Applied Mechanics, China Agricultural University, Beijing 100083 (China)

    2014-04-21

    Carbon nanotube (CNT) was first discovered by Sumio Iijima. It has aroused extensive attentions of scholars from all over the world. Over the past two decades, we have acquired a lot of methods to synthesize carbon nanotubes and learn their many incredible mechanical properties such as experimental methods, theoretical analyses, and computer simulations. However, the studies of experiments need lots of financial, material, and labor resources. The calculations will become difficult and time-consuming, and the calculations may be even beyond the realm of possibility when the scale of simulations is large, as for computer simulations. Therefore, it is necessary for us to explore a reasonable continuum model, which can be applied into nano-scale. This paper attempts to develop a mathematical model of a small-radius carbon nanotube based on continuum theory. An Isotropic circular cross-section, Timoshenko beam model is used as a simplified mechanical model for the small-radius carbon nanotube. Theoretical part is mainly based on modified couple stress theory to obtain the numerical solutions of buckling deformation. Meanwhile, the buckling behavior of the small radius carbon nanotube is simulated by Molecular Dynamics method. By comparing with the numerical results based on modified couple stress theory, the dependence of the small-radius carbon nanotube mechanical behaviors on its elasticity constants, small-size effect, geometric nonlinearity, and shear effect is further studied, and an estimation of the small-scale parameter of a CNT (5, 5) is obtained.

  2. Nonlinear buckling analyses of a small-radius carbon nanotube

    Science.gov (United States)

    Liu, Ning; Wang, Yong-Gang; Li, Min; Jia, Jiao

    2014-04-01

    Carbon nanotube (CNT) was first discovered by Sumio Iijima. It has aroused extensive attentions of scholars from all over the world. Over the past two decades, we have acquired a lot of methods to synthesize carbon nanotubes and learn their many incredible mechanical properties such as experimental methods, theoretical analyses, and computer simulations. However, the studies of experiments need lots of financial, material, and labor resources. The calculations will become difficult and time-consuming, and the calculations may be even beyond the realm of possibility when the scale of simulations is large, as for computer simulations. Therefore, it is necessary for us to explore a reasonable continuum model, which can be applied into nano-scale. This paper attempts to develop a mathematical model of a small-radius carbon nanotube based on continuum theory. An Isotropic circular cross-section, Timoshenko beam model is used as a simplified mechanical model for the small-radius carbon nanotube. Theoretical part is mainly based on modified couple stress theory to obtain the numerical solutions of buckling deformation. Meanwhile, the buckling behavior of the small radius carbon nanotube is simulated by Molecular Dynamics method. By comparing with the numerical results based on modified couple stress theory, the dependence of the small-radius carbon nanotube mechanical behaviors on its elasticity constants, small-size effect, geometric nonlinearity, and shear effect is further studied, and an estimation of the small-scale parameter of a CNT (5, 5) is obtained.

  3. Improved Composites Using Crosslinked, Surface-Modified Carbon Nanotube Materials

    Science.gov (United States)

    Baker, James Stewart

    2014-01-01

    Individual carbon nanotubes (CNTs) exhibit exceptional tensile strength and stiffness; however, these properties have not translated well to the macroscopic scale. Premature failure of bulk CNT materials under tensile loading occurs due to the relatively weak frictional forces between adjacent CNTs, leading to poor load transfer through the material. When used in polymer matrix composites (PMCs), the weak nanotube-matrix interaction leads to the CNTs providing less than optimal reinforcement.Our group is examining the use of covalent crosslinking and surface modification as a means to improve the tensile properties of PMCs containing carbon nanotubes. Sheet material comprised of unaligned multi-walled carbon nanotubes (MWCNT) was used as a drop-in replacement for carbon fiber in the composites. A variety of post-processing methods have been examined for covalently crosslinking the CNTs to overcome the weak inter-nanotube shear interactions, resulting in improved tensile strength and modulus for the bulk sheet material. Residual functional groups from the crosslinking chemistry may have the added benefit of improving the nanotube-matrix interaction. Composites prepared using these crosslinked, surface-modified nanotube sheet materials exhibit superior tensile properties to composites using the as received CNT sheet material.

  4. In silico assembly and nanomechanical characterization of carbon nanotube buckypaper.

    Science.gov (United States)

    Cranford, Steven W; Buehler, Markus J

    2010-07-01

    Carbon nanotube sheets or films, also known as 'buckypaper', have been proposed for use in actuating, structural and filtration systems, based in part on their unique and robust mechanical properties. Computational modeling of such a fibrous nanostructure is hindered by both the random arrangement of the constituent elements as well as the time- and length-scales accessible to atomistic level molecular dynamics modeling. Here we present a novel in silico assembly procedure based on a coarse-grain model of carbon nanotubes, used to attain a representative mesoscopic buckypaper model that circumvents the need for probabilistic approaches. By variation in assembly parameters, including the initial nanotube density and ratio of nanotube type (single- and double-walled), the porosity of the resulting buckypaper can be varied threefold, from approximately 0.3 to 0.9. Further, through simulation of nanoindentation, the Young's modulus is shown to be tunable through manipulation of nanotube type and density over a range of approximately 0.2-3.1 GPa, in good agreement with experimental findings of the modulus of assembled carbon nanotube films. In addition to carbon nanotubes, the coarse-grain model and assembly process can be adapted for other fibrous nanostructures such as electrospun polymeric composites, high performance nonwoven ballistic materials, or fibrous protein aggregates, facilitating the development and characterization of novel nanomaterials and composites as well as the analysis of biological materials such as protein fiber films and bulk structures.

  5. Experiments on Void Fraction of CO2 Flow Boiling in a Horizontal Micro-fin Tube

    Science.gov (United States)

    Kondou, Chieko; Higashiiue, Shinya; Kuwahara, Ken; Koyama, Shigeru

    This paper deals with an experimental investigation on the void fraction of CO2 flow boiling in a horizontal micro-fin tube. The mean void fraction in the insulated 400 mm length sampling section, which is located next to the test evaporator, has measured by the quick closing valve method. The experimental data have been obtained in mass flux range of 200 to 455 kg/(m2s) and the refrigerant pressure range of 3.5 to 5.0 MPa. It is confirmed that the relation between void fraction and quality is affected by both mass flux and pressure. The experimental results are also compared with two previous correlations for horizontal smooth tubes, which are proposed by Butterworth and Smith. The present data satisfactorily agreed with Butterworth's correlation in the range of quality from 0.03 to 0.99. However, Smith's correlation is found to predict slightly higher than present data. As a trial, the empirical correlation of void fraction, based on the experimental slip ratios, is proposed.

  6. Yarn spun from carbon nanotube forests: Production, structure, properties and applications

    Institute of Scientific and Technical Information of China (English)

    Menghe Miao

    2013-01-01

    The discovery ofdrawable carbon nanotube forests opened up the possibility of constructing a wide range of pure carbon nanotube macrostructures and sparked interests in developing applications from these structures,especially pure carbon nanotube yarns.This review examines the various facets of the drawable carbon nanotube forests,synthesis and drawability,and their resulting yarns,structure,production,properties and applications.The structure,formation and properties of carbon nanotube yarns are compared with those of conventional textile yarns in order to obtain a better understanding of the science,structural mechanics and processing technology involved in carbon nanotube yarns.

  7. Ultra-small Palladium Nanoparticle Decorated Carbon Nanotubes: Conductivity and Reactivity.

    Science.gov (United States)

    Li, Xiuting; Batchelor-McAuley, Christopher; Tschulik, Kristina; Shao, Lidong; Compton, Richard G

    2015-08-03

    Carbon nanotubes decorated with ultra-small metal nanoparticles are of great value in catalysis. We report that individual multiwalled carbon nanotubes decorated with ultra-small palladium nanoparticles can be detected by using the nano-impacts method. The high conductivity and reactivity of each decorated carbon nanotube is directly evidenced; this is achieved through studying the proton-reduction reaction for the underpotential deposition of hydrogen onto the nanoparticles decorated on the carbon nanotube walls. The reductive spikes from current amplification are analyzed to estimate the approximate length of the decorated carbon nanotubes, revealing that the decorated carbon nanotubes are electroactive along its entire length of several micrometers.

  8. Enhancing the crystalline degree of carbon nanotubes by acid treatment, air oxidization and heat treatment

    Institute of Scientific and Technical Information of China (English)

    Chensha Li; Baoyou Zhang; Xingjuan Chen; Xiaoqing Hu; Ji Liang

    2005-01-01

    Three approaches of treating carbon nanotubes (CNTs) including acid treatment, air oxidization and heat treatment at high temperature were studied to enhance the crystalline degree of carbon nanotubes. High temperature heat-treatment elevates the crystalline degree of carbon nanotubes. Acid treatment removes parts of amorphous carbonaceous matter through its oxidization effect.Air oxidization disperses carbon nanotubes and amorphous carbonaceous matter. The treatment of combining acid treatment with heat-treatment further elevates the crystalline degree of carbon nanotubes comparing with acid treatment or heat-treatment. The combination of the three treatments creates the thorough effects of enhancing the crystalline degree of carbon nanotubes.

  9. Radial breathing mode of carbon nanotubes subjected to axial pressure.

    Science.gov (United States)

    Lei, Xiao-Wen; Ni, Qing-Qing; Shi, Jin-Xing; Natsuki, Toshiaki

    2011-08-11

    In this paper, a theoretical analysis of the radial breathing mode (RBM) of carbon nanotubes (CNTs) subjected to axial pressure is presented based on an elastic continuum model. Single-walled carbon nanotubes (SWCNTs) are described as an individual elastic shell and double-walled carbon nanotubes (DWCNTs) are considered to be two shells coupled through the van der Waals force. The effects of axial pressure, wave numbers and nanotube diameter on the RBM frequency are investigated in detail. The validity of these theoretical results is confirmed through the comparison of the experiment, calculation and simulation. Our results show that the RBM frequency is linearly dependent on the axial pressure and is affected by the wave numbers. We concluded that RBM frequency can be used to characterize the axial pressure acting on both ends of a CNT.

  10. Electronic properties of multi-defected zigzag carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Electronic properties of multi-defected zigzag single-walled carbon nanotubes are investigated by use of the tight-binding Green’s function method. The Stone-Wales defects and the vacancies are considered. We find that the conductance sensitively depends on the realistic defect configurations for the metallic zigzag carbon nanotubes. Interestingly, the electronic transport properties of the nanotubes with three vacancies can be considered as the sum effect of two double-vacancies, while those with Stone-Wales defects can not. The electron interference along the longitudinal axis and the transport blocking are observed, which may be useful for understanding the electron transport behavior of carbon nanotube in experiments.

  11. Impact response by a foamlike forest of coiled carbon nanotubes

    Science.gov (United States)

    Daraio, Chiara; Nesterenko, Vitali F.; Jin, Sungho; Wang, Wei; Rao, Apparao M.

    2006-09-01

    We studied the dynamic response of a foamlike forest of coiled carbon nanotubes under high strain rate deformation using a simple drop-ball test. The method is based on measuring the dynamic force between the ball and the foam on the substrate during the stages of penetration and restitution. The analysis of the forest's morphology after impact has shown no trace of plastic deformation and a full recovery of the foamlike layer of coiled carbon nanotubes under various impact velocities. The contact force exhibits a strongly nonlinear dependence on displacement and appears fundamentally different from the response of a forest of straight carbon nanotubes, and from the Hertzian type of plane-sphere interaction. "Brittle" fracture of the foamlike layer is observed after repeated high velocity impacts. Such layers of coiled nanotubes may be used as a strongly nonlinear spring in discrete systems for monitoring their dynamic behavior and as a nanostructure for localized microimpact protection.

  12. GUIDED CIRCUMFERENTIAL WAVES IN DOUBLE-WALLED CARBON NANOTUBES

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A model of guided circumferential waves propagating in double-walled carbon nanotubes is built by the theory of wave propagation in continuum mechanics, while the van der Waals force between the inner and outer nanotube has been taken into account in the model. The dispersion curves of the guided circumferential wave propagation are studied, and some dispersion characteristics are illustrated by comparing with those of single-walled carbon nanotubes. It is found that in double-walled carbon nanotubes, the guided circumferential waves will propagate in more dispersive ways. More interactions between neighboring wave modes may take place. In particular, it has been found that a couple of wave modes may disappear at a certain frequency and that, while a couple of wave modes disappear, another new couple of wave modes are excited at the same wave number.

  13. Dispersion and reinforcing mechanism of carbon nanotubes in epoxy nanocomposites

    Indian Academy of Sciences (India)

    Smrutisikha Bal

    2010-02-01

    Carbon nanotube based epoxy composites have been fabricated at room temperature and refrigeration process using sonication principle. Flexural moduli, electrical conductivity, glass transition temperature of epoxy resin as well as nanocomposite samples have been determined. Distribution behaviour of carbon nanotubes in the epoxy matrix was examined through scanning electron microscopy. Composite samples showed better properties than resin samples due to strengthening effect of the filled nanotubes. Refrigerated nanocomposites obtained increasing mechanical property because of better dispersion due to low temperature settlement of polymers. Improvement of electrical conductivity was due to the fact that aggregated phases form a conductive three-dimensional network throughout the whole sample. The increasing glass transition temperature was indicative of restricting movement of polymer chains that ascribe strong interaction presented between carbon nanotubes and epoxy chains that was again supplemented by Raman study and SEM.

  14. Carbon nanotube and conducting polymer composites for supercapacitors

    Institute of Scientific and Technical Information of China (English)

    Chuang Peng; Shengwen Zhang; Daniel Jewell; George Z. Chen

    2008-01-01

    Composites of carbon nanotubes and conducting polymers can be prepared via chemical synthesis, electrochemical deposition on pre-formed carbon nanotube electrodes, or by electrochemical co-deposition. The composites combine the large pseudocapacitance of the conducting polymers with the fast charging/discharging double-layer capacitance and excellent mechanical properties of the carbon nanotubes. The electrochemically co-deposited composites are the most homogeneous and show an unusual interaction between thepolymer and nanotubes, giving rise to a strengthened electron delocalisation and conjugation along the polymer chains. As a result they exhibit excellent electrochemical charge storage properties and fast charge/discharge switching, making them promising electrode mate-rials for high power supercapacitors.

  15. How fast does water flow in carbon nanotubes?

    DEFF Research Database (Denmark)

    Kannam, Sridhar; Todd, Billy; Hansen, Jesper Schmidt

    2013-01-01

    the slip length using equilibrium molecular dynamics (EMD) simulations, from which the interfacial friction between water and carbon nanotubes can be found, and also via external field driven non-equilibrium molecular dynamics simulations (NEMD). We discuss some of the issues in simulation studies which......The purpose of this paper is threefold. First, we review the existing literature on flow rates of water in carbon nanotubes. Data for the slip length which characterizes the flow rate are scattered over 5 orders of magnitude for nanotubes of diameter 0.81–10 nm. Second, we precisely compute...... and reliably extrapolate the results for the slip length to values of the field corresponding to experimentally accessible pressure gradients. Finally, we comment on several issues concerning water flow rates in carbon nanotubes which may lead to some future research directions in this area....

  16. Electroluminescent Polymers and Carbon Nanotubes for Flat Panel Displays

    Institute of Scientific and Technical Information of China (English)

    Liming Dai; Limin Dong; Mei Gao; Shaoming Huang; Oddvar Johansen; Albert W.H.Mau,Zoran Vasic; Berthold Winkler; Yongyuang Yang

    2000-01-01

    polymeric light-emitting diodes(LEDs) with sufficient brightness. efficiencies, low driving voltages, and various interesting features have been reported. The relatively short device lifetime, however, still remains as a major problem to be solved before any commercial applications will be realized. In this regard,carbon nanotubes have recently been proposed as more robust electron field emitters for flat panel displays. We have synthesised large arrays of vertically aligned carbon nanotubes, from which micropatterns of the aligned nanotubes suitable for flat panel displays were fabricated on various substrates. In this paper, we summarise our work on the synthesis and microfabrication of electroluminescent polymers and carbon nanotubes for flat panel displays with reference to other complementary work as appropriate.

  17. Electronic and optoelectronic nano-devices based on carbon nanotubes.

    Science.gov (United States)

    Scarselli, M; Castrucci, P; De Crescenzi, M

    2012-08-08

    The discovery and understanding of nanoscale phenomena and the assembly of nanostructures into different devices are among the most promising fields of material science research. In this scenario, carbon nanostructures have a special role since, in having only one chemical element, they allow physical properties to be calculated with high precision for comparison with experiment. Carbon nanostructures, and carbon nanotubes (CNTs) in particular, have such remarkable electronic and structural properties that they are used as active building blocks for a large variety of nanoscale devices. We review here the latest advances in research involving carbon nanotubes as active components in electronic and optoelectronic nano-devices. Opportunities for future research are also identified.

  18. Mechanical behavior of ultralong multiwalled carbon nanotube mats

    Science.gov (United States)

    Deck, Christian P.; Flowers, Jason; McKee, Gregg S. B.; Vecchio, Kenneth

    2007-01-01

    Carbon nanotubes (CNTs) have been a subject of great interest partially due to their potential for exceptional material properties. Improvements in synthesis methods have facilitated the production of ultralong CNT mats, with lengths in the millimeter range. The increased length of these ultralong mats has, in return, opened the way to greater flexibility to probe their mechanical response. In this work, mats of dense, well-aligned, multiwalled carbon nanotubes were grown with a vapor-phase chemical vapor deposition technique using ferrocene and benzene as reactants, and subsequently tested in both tension and compression using two methods, in a thermomechanical analyzer and in situ inside a scanning electron microscope. In compression, measured stiffness was very low, due to buckling of the nanotubes. In tension, the nanotube mats behaved considerably stiffer; however, they were still more compliant than expected for nanotubes (˜1TPa). Analysis of both the growth method used and the nanotube mat fracture surface suggests that the mats grown in this method are not composed of continuous nanotubes and their strengths actually closely match those of woven nanotube yarns and ropes.

  19. Highly Ordered Carbon Nanotube Arrays with Open Ends Grown in Anodic Alumina Nanoholes

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Highly ordered multiwalled carbon nanotube arrays were fabricated by pyrolysis of acetylene within anodic alumina templates.Nanotubes are very uniform in diameter and open at both ends. High resolution transmission electron microscopy and electron diffraction analysis show that the carbon nanotubes are well graphitized. These standing and open carbon nanotubes are possible to offer a potential elegant technique for electron emitting devices,chemical functionalization and nanotube composites.

  20. Understanding the toxicity of carbon nanotubes.

    Science.gov (United States)

    Liu, Ying; Zhao, Yuliang; Sun, Baoyun; Chen, Chunying

    2013-03-19

    Because of their unique physical, chemical, electrical, and mechanical properties, carbon nanotubes (CNTs) have attracted a great deal of research interest and have many potential applications. As large-scale production and application of CNTs increases, the general population is more likely to be exposed to CNTs either directly or indirectly, which has prompted considerable attention about human health and safety issues related to CNTs. Although considerable experimental data related to CNT toxicity at the molecular, cellular, and whole animal levels have been published, the results are often conflicting. Therefore, a systematic understanding of CNT toxicity is needed but has not yet been developed. In this Account, we highlight recent investigations into the basis of CNT toxicity carried out by our team and by other laboratories. We focus on several important factors that explain the disparities in the experimental results of nanotoxicity, such as impurities, amorphous carbon, surface charge, shape, length, agglomeration, and layer numbers. The exposure routes, including inhalation, intravenous injection, or dermal or oral exposure, can also influence the in vivo behavior and fate of CNTs. The underlying mechanisms of CNT toxicity include oxidative stress, inflammatory responses, malignant transformation, DNA damage and mutation (errors in chromosome number as well as disruption of the mitotic spindle), the formation of granulomas, and interstitial fibrosis. These findings provide useful insights for de novo design and safe application of carbon nanotubes and their risk assessment to human health. To obtain reproducible and accurate results, researchers must establish standards and reliable detection methods, use standard CNT samples as a reference control, and study the impact of various factors systematically. In addition, researchers need to examine multiple types of CNTs, different cell lines and animal species, multidimensional evaluation methods, and