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Sample records for carbon nanotube coatings

  1. Carbon nanotube coatings as chemical absorbers

    Science.gov (United States)

    Tillotson, Thomas M.; Andresen, Brian D.; Alcaraz, Armando

    2004-06-15

    Airborne or aqueous organic compound collection using carbon nanotubes. Exposure of carbon nanotube-coated disks to controlled atmospheres of chemical warefare (CW)-related compounds provide superior extraction and retention efficiencies compared to commercially available airborne organic compound collectors. For example, the carbon nanotube-coated collectors were four (4) times more efficient toward concentrating dimethylmethyl-phosphonate (DMMP), a CW surrogate, than Carboxen, the optimized carbonized polymer for CW-related vapor collections. In addition to DMMP, the carbon nanotube-coated material possesses high collection efficiencies for the CW-related compounds diisopropylaminoethanol (DIEA), and diisopropylmethylphosphonate (DIMP).

  2. Carbon nanotube based functional superhydrophobic coatings

    Science.gov (United States)

    Sethi, Sunny

    The main objective of this dissertation is synthesis of carbon nanotube (CNT) based superhydrophobic materials. The materials were designed such that electrical and mechanical properties of CNTs could be combined with superhydrophobicity to create materials with unique properties, such as self-cleaning adhesives, miniature flotation devices, ice-repellant coatings, and coatings for heat transfer furnaces. The coatings were divided into two broad categories based on CNT structure: Vertically aligned CNT arrays (VA coatings) and mesh-like (non-aligned) carbon nanotube arrays (NA coatings). VA coatings were used to create self-cleaning adhesives and flexible field emission devices. Coatings with self cleaning property along with high adhesiveness were inspired from structure found on gecko foot. Gecko foot is covered with thousands of microscopic hairs called setae; these setae are further divided into hundreds of nanometer sized hairs called spatulas. When gecko presses its foot against any surface, these hairs bend and conform to the topology of the surface resulting into very large area of contact. Such large area of intimate contact allows geckos to adhere to surfaces using van der Waals (vdW) interactions alone. VA-CNTs adhere to a variety of surfaces using a similar mechanism. CNTs of suitable diameter could withstand four times higher adhesion force than gecko foot. We found that upon soiling these CNT based adhesives (gecko tape) could be cleaned using a water droplet (lotus effect) or by applying vibrations. These materials could be used for applications requiring reversible adhesion. VA coatings were also used for developing field emission devices. A single CNT can emit electrons at very low threshold voltages. Achieving efficient electron emission on large scale has a lot of challenges such as screening effect, pull-off and lower current efficiency. We have explored the use of polymer-CNT composite structures to overcome these challenges in this work. NA

  3. Tough ceramic coatings: Carbon nanotube reinforced silica sol-gel

    Energy Technology Data Exchange (ETDEWEB)

    Lopez, A.J., E-mail: antoniojulio.lopez@urjc.es [Dept. de Ciencia e Ingenieria de Materiales, ESCET, Universidad Rey Juan Carlos, C/Tulipan s/n, Mostoles 28933, Madrid (Spain); Rico, A.; Rodriguez, J.; Rams, J. [Dept. de Ciencia e Ingenieria de Materiales, ESCET, Universidad Rey Juan Carlos, C/Tulipan s/n, Mostoles 28933, Madrid (Spain)

    2010-08-15

    Silica coatings reinforced with carbon nanotubes were produced via sol-gel route using two mixing techniques of the sol-gel precursors, mechanical and ultrasonic mixing, and dip-coating as deposition process on magnesium alloy substrates. Effective incorporation and distribution of 0.1 wt.% of carbon nanotubes in the amorphous silica matrix of the coatings were achieved using both techniques. Fabrication procedure determines the morphological aspects of the coating. Only mechanical mixing process produced coatings dense and free of defects. Nanoindentation technique was used to examine the influence of the fabrication process in the mechanical features of the final coatings, i.e. indentation fracture toughness, Young's modulus and hardness. A maximum toughening effect of about 24% was achieved in silica coatings reinforced with carbon nanotubes produced by the mechanical mixing route. Scanning electron microscopy investigation revealed that the toughening of these reinforced coatings was mainly due to bridging effect of the reinforcement.

  4. Multilayered Polymer Coated Carbon Nanotubes to Deliver Dasatinib

    OpenAIRE

    Moore, Thomas L.; Grimes, Stuart W.; Lewis, Robert L.; Alexis, Frank

    2013-01-01

    Multilayered, multifunctional polymer coatings were grafted onto carbon nanotubes (CNT) using a one-pot, ring-opening polymerization in order to control the release kinetic and therapeutic efficacy of dasatinib. Biocompatible, biodegradable multilayered coatings composed of poly(glycolide) (PGA), and poly(lactide) (PLA) were polymerized directly onto hydroxyl-functionalized CNT surfaces. Sequential addition of monomers into the reaction vessel enabled multilayered coatings of PLA-PGA, or PGA-...

  5. Multifunctional Polymer-Coated Carbon Nanotubes for Safe Drug Delivery.

    Science.gov (United States)

    Moore, Thomas L; Pitzer, Joshua E; Podila, Ramakrishna; Wang, Xiaojia; Lewis, Robert L; Grimes, Stuart W; Wilson, James R; Skjervold, Even; Brown, Jared M; Rao, Apparao; Alexis, Frank

    2013-04-01

    Though progress in the use carbon nanotubes in medicine has been most encouraging for therapeutic and diagnostic applications, any translational success must involve overcoming the toxicological and surface functionalization challenges inherent in the use of such nanotubes. Ideally, a carbon nanotube-based drug delivery system would exhibit low toxicity, sustained drug release, and persist in circulation without aggregation. We report a carbon nanotube (CNT) coated with a biocompatible block-co-polymer composed of poly(lactide)-poly(ethylene glycol) (PLA-PEG) to reduce short-term and long-term toxicity, sustain drug release of paclitaxel (PTX), and prevent aggregation. The copolymer coating on the surface of CNTs significantly reduces in vitro toxicity in human umbilical vein endothelial cells (HUVEC) and U-87 glioblastoma cells. Moreover, coating reduces in vitro inflammatory response in rat lung epithelial cells. Compared to non-coated CNTs, in vivo studies show no long-term inflammatory response with CNT coated with PLA-PEG (CLP) and the surface coating significantly decreases acute toxicity by doubling the maximum tolerated dose in mice. Using polymer coatings, we can encapsulate PTX and release over one week to increase the therapeutic efficacy compared to free drugs. In vivo biodistribution and histology studies suggests a lower degree of aggregation in tissues in that CLP accumulate more in the brain and less in the spleen than the CNT-PLA (CL) formulation.

  6. Carbon nanotube and graphene nanoribbon-coated conductive Kevlar fibers.

    Science.gov (United States)

    Xiang, Changsheng; Lu, Wei; Zhu, Yu; Sun, Zhengzong; Yan, Zheng; Hwang, Chi-Chau; Tour, James M

    2012-01-01

    Conductive carbon material-coated Kevlar fibers were fabricated through layer-by-layer spray coating. Polyurethane was used as the interlayer between the Kevlar fiber and carbon materials to bind the carbon materials to the Kevlar fiber. Strongly adhering single-walled carbon nanotube coatings yielded a durable conductivity of 65 S/cm without significant mechanical degradation. In addition, the properties remained stable after bending or water washing cycles. The coated fibers were analyzed using scanning electron microcopy and a knot test. The as-produced fiber had a knot efficiency of 23%, which is more than four times higher than that of carbon fibers. The spray-coating of graphene nanoribbons onto Kevlar fibers was also investigated. These flexible coated-Kevlar fibers have the potential to be used for conductive wires in wearable electronics and battery-heated armors. © 2011 American Chemical Society

  7. Textile fibers coated with carbon nanotubes for smart clothing applications

    Science.gov (United States)

    Lepak, Sandra; Lalek, Bartłomiej; Janczak, Daniel; Dybowska-Sarapuk, Łucja; Krzemiński, Jakub; Jakubowska, Małgorzata; Łekawa-Raus, Agnieszka

    2017-08-01

    Carbon nanomaterials: graphene, fullerenes and in particular carbon nanotubes (CNTs) are extremely interesting and extraordinary materials. It is mostly thanks to theirs unusual electrical and mechanical properties. Carbon nanotubes are increasingly examined to enable its usage in many fields of science and technology. It has been reported that there is a high possibility to use CNTs in electronics, optics, material engineering, biology or medicine. However, this material still interests and inspire scientists around the world and the list of different CNTs applications is constantly expanding. In this paper we are presenting a study on the possibility of application carbon nanotubes as a textile fiber coating for smart clothing applications. Various suspensions and pastes containing CNTs have been prepared as a possible coating onto textile fibers. Different application techniques have also been tested. Those techniques included painting with nanotube suspension, spray coating of suspensions and immersion. Following textile fibers were subject to tests: cotton, silk, polyester, polyamide and wool. Obtained composites materials were then characterized electrically by measuring the electrical resistance.

  8. Preparation of Nickel-Copper Bilayers Coated on Single-Walled Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Zhong Zheng

    2015-01-01

    Full Text Available Due to oxidizability of copper coating on carbon nanotubes, the interfacial bond strength between copper coating and its matrix is weak, which leads to the reduction of the macroscopic properties of copper matrix composite. The electroless coating technics was applied to prepare nickel-copper bilayers coated on single-walled carbon nanotubes. The coated single-walled carbon nanotubes were characterized through transmission electron microscope spectroscopy, field-emission electron microscope spectroscopy, X-ray diffractometry, and thermogravimetric analysis. The results demonstrated that the nickel-copper bilayers coated on single-walled carbon nanotubes possessed higher purity of unoxidized copper fine-grains than copper monolayers.

  9. Interactions between the glass fiber coating and oxidized carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Ku-Herrera, J.J., E-mail: jesuskuh@live.com.mx [Centro de Investigación Científica de Yucatán A.C., Unidad de Materiales, Calle 43 No.130, Col. Chuburná de Hidalgo. C.P., 97200 Mérida, Yucatán (Mexico); Avilés, F., E-mail: faviles@cicy.mx [Centro de Investigación Científica de Yucatán A.C., Unidad de Materiales, Calle 43 No.130, Col. Chuburná de Hidalgo. C.P., 97200 Mérida, Yucatán (Mexico); Nistal, A. [Instituto de Cerámica y Vidrio (ICV-CSIC), Kelsen 5, 28049 Madrid (Spain); Cauich-Rodríguez, J.V. [Centro de Investigación Científica de Yucatán A.C., Unidad de Materiales, Calle 43 No.130, Col. Chuburná de Hidalgo. C.P., 97200 Mérida, Yucatán (Mexico); Rubio, F.; Rubio, J. [Instituto de Cerámica y Vidrio (ICV-CSIC), Kelsen 5, 28049 Madrid (Spain); Bartolo-Pérez, P. [Departamento de Física Aplicada, Cinvestav, Unidad Mérida, C.P., 97310 Mérida, Yucatán (Mexico)

    2015-03-01

    Graphical abstract: - Highlights: • Oxidized multiwall carbon nanotubes (MWCNTs) were deposited onto E-glass fibers. • The role of the fiber coating on the deposition of MWCNTs on the fibers is studied. • A rather homogeneous deposition of MWCNTs is achieved if the coating is maintained. • Multiple oxygen-containing groups were found in the analysis of the fiber coating. • Evidence of chemical interaction between MWCNTs and the fiber coating was found. - Abstract: Chemically oxidized multiwall carbon nanotubes (MWCNTs) were deposited onto commercial E-glass fibers using a dipping procedure assisted by ultrasonic dispersion. In order to investigate the role of the fiber coating (known as “sizing”), MWCNTs were deposited on the surface of as-received E-glass fibers preserving the proprietary coating as well as onto glass fibers which had the coating deliberately removed. Scanning electron microscopy and Raman spectroscopy were used to assess the distribution of MWCNTs onto the fibers. A rather homogeneous coverage with high density of MWCNTs onto the glass fibers is achieved when the fiber coating is maintained. Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and nuclear magnetic resonance (NMR) analyses of the chemical composition of the glass fiber coating suggest that such coating is a complex mixture with multiple oxygen-containing functional groups such as hydroxyl, carbonyl and epoxy. FTIR and XPS of MWCNTs over the glass fibers and of a mixture of MWCNTs and fiber coating provided evidence that the hydroxyl and carboxyl groups of the oxidized MWCNTs react with the oxygen-containing functional groups of the glass fiber coating, forming hydrogen bonding and through epoxy ring opening. Hydrogen bonding and ester formation between the functional groups of the MWCNTs and the silane contained in the coating are also possible.

  10. Multilayered Polymer Coated Carbon Nanotubes to Deliver Dasatinib

    Science.gov (United States)

    Moore, Thomas L.; Grimes, Stuart W.; Lewis, Robert L.; Alexis, Frank

    2014-01-01

    Multilayered, multifunctional polymer coatings were grafted onto carbon nanotubes (CNT) using a one-pot, ring-opening polymerization in order to control the release kinetic and therapeutic efficacy of dasatinib. Biocompatible, biodegradable multilayered coatings composed of poly(glycolide) (PGA), and poly(lactide) (PLA) were polymerized directly onto hydroxyl-functionalized CNT surfaces. Sequential addition of monomers into the reaction vessel enabled multilayered coatings of PLA-PGA, or PGA-PLA. Poly(ethylene glycol) capped the polymer chain ends, resulting in a multifunctional amphiphilic coating. Multilayer polymer coatings on CNTs enabled control of anticancer dasatinib’s release kinetics and enhanced the in vitro therapeutic efficacy against U-87 glioblastoma compared to monolayer polymer coatings. PMID:24294824

  11. Multilayered polymer-coated carbon nanotubes to deliver dasatinib.

    Science.gov (United States)

    Moore, Thomas L; Grimes, Stuart W; Lewis, Robert L; Alexis, Frank

    2014-01-06

    Multilayered, multifunctional polymer coatings were grafted onto carbon nanotubes (CNTs) using a one-pot, ring-opening polymerization in order to control the release kinetic and therapeutic efficacy of dasatinib. Biocompatible, biodegradable multilayered coatings composed of poly(glycolide) (PGA) and poly(lactide) (PLA) were polymerized directly onto hydroxyl-functionalized CNT surfaces. Sequential addition of monomers into the reaction vessel enabled multilayered coatings of PLA-PGA or PGA-PLA. Poly(ethylene glycol) capped the polymer chain ends, resulting in a multifunctional amphiphilic coating. Multilayer polymer coatings on CNTs enabled control of the anticancer drug dasatinib's release kinetics and enhanced the in vitro therapeutic efficacy against U-87 glioblastoma compared to monolayer polymer coatings.

  12. Designing transparent superamphiphobic coatings directed by carbon nanotubes.

    Science.gov (United States)

    Zhu, Xiaotao; Zhang, Zhaozhu; Ren, Guina; Men, Xuehu; Ge, Bo; Zhou, Xiaoyan

    2014-05-01

    Creating surfaces with superamphiphobic property and optical transparency simultaneously would have fundamental and practical significance but has been proven extremely challenging. Herein, we develop a transparent superamphiphobic coating using carbon nanotubes (CNTs) as the template by a facile approach. CNTs enwrapped with SiO2 coating was produced by a sol-gel method and then sprayed onto the glass slides to form coatings. Subsequent thermal treatment and surface fluoration allowed the sprayed coating to exhibit enhanced transparency across a broad spectrum of ultraviolet and visible wavelengths and also display superrepellency toward water and a number of organic liquids, such as dodecane. The obtained transparent coating can sustain its superamphiphobicity even after thermal treatment at 400 °C. Separate experiment demonstrated that the CNTs-directed geometrical structure played a key role in establishing superamphiphobicity. Copyright © 2014. Published by Elsevier Inc.

  13. Thermal conductive epoxy enhanced by nanodiamond-coated carbon nanotubes

    Science.gov (United States)

    Zhao, Bo; Jiang, Guohua

    2017-11-01

    Nanodiamond (ND) particles were coated on the surface of carbon nanotubes (CNTs) by chemical reactions. Reliable bonding was formed by the combination of acyl chloride on NDs and amine group on CNTs. ND coated CNTs (CNT-ND) were dispersed into epoxy to fabricate thermal conductive resins. The results show that the surface energy of CNTs is decreased by the coated NDs, which is contributed to the excellent dispersion of CNT-NDs in the epoxy matrix. The heat-transfer channels were built by the venous CNTs cooperating with the coated NDs, which not only plays an effective role of heat conduction for CNTs and NDs, but also avoids the electrical leakage by the protection of NDs surrounding outside of CNTs. Electrical and thermal conductance measurements demonstrate that the influence of the CNT-ND incorporation on the electrical conductance is minor, however, the thermal conductivity is improved significantly for the epoxy filled with CNT-ND.[Figure not available: see fulltext.

  14. The in vitro biomineralization and cytocompatibility of polydopamine coated carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Yan Penghua [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, 18 Tianshui Middle Road, Lanzhou 730000 (China); Key Laboratory of Polymer Materials of Gansu Province, College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070 (China); Wang Jinqing, E-mail: jqwang@licp.cas.cn [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, 18 Tianshui Middle Road, Lanzhou 730000 (China); Wang Lin; Liu Bin [School of Stomatology, Lanzhou University, Lanzhou 730000 (China); Lei Ziqiang [Key Laboratory of Polymer Materials of Gansu Province, College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070 (China); Yang Shengrong, E-mail: sryang@lzb.ac.cn [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, 18 Tianshui Middle Road, Lanzhou 730000 (China); Key Laboratory of Polymer Materials of Gansu Province, College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou 730070 (China)

    2011-03-15

    In this work, polydopamine coated carbon nanotubes were firstly prepared by a simple and feasible route. Then, for comparison, the in vitro bioactivity and cytocompatibility of the carbon nanotubes and the polydopamine coated carbon nanotubes were assessed by immersion study in simulated body fluids and 3-(4,5-dimethyldiazol-2-yl)-2,5-diphenyl tetrazolium bromide test using osteoblast cells (MC3T3-E1), respectively. As a result, it has been demonstrated that the introduction of polydopamine coating can greatly enhance the bioactivity and promote cell proliferation of the carbon nanotubes. The improvement of bioactive behavior is attributed to the good combination of catecholamines structure of the polydopamine and the structural advantages of carbon nanotubes as a framework material. It is anticipated that the polydopamine coated carbon nanotubes would find potential applications in bone tissue engineering and other biomedical areas.

  15. Effects of Two Purification Pretreatments on Electroless Copper Coating over Single-Walled Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Zhong Zheng

    2014-01-01

    Full Text Available To achieve the reinforcement of copper matrix composite by single-walled carbon nanotubes, a three-step-refluxing purification of carbon nanotubes sample with HNO3-NaOH-HCl was proposed and demonstrated. A previously reported purification process using an electromagnetic stirring with H2O2/HCl mixture was also repeated. Then, the purified carbon nanotubes were coated with copper by the same electroless plating process. At the end, the effects of the method on carbon nanotubes themselves and on copper coating were determined by transmission electron microscope spectroscopy, scanning electron microscope spectroscopy, X-ray diffractometry, thermogravimetric analysis, Fourier transformed infrared spectroscopy, and energy dispersive spectrometry. It was clearly confirmed that both of the two processes could remove most of iron catalyst particles and carbonaceous impurities without significant damage to carbon nanotubes. The thermal stability of the sample purified by H2O2/HCl treatment was slightly higher than that purified by HNO3-NaOH-HCl treatment. Nevertheless, the purification by HNO3-NaOH-HCl treatment was more effective for carboxyl functionalization on nanotubes than that by H2O2/HCl treatment. The Cu-coating on carbon nanotubes purified by both purification processes was complete, homogenous, and continuous. However, the Cu-coating on carbon nanotubes purified by H2O2/HCl was oxidized more seriously than those on carbon nanotubes purified by HNO3-NaOH-HCl treatment.

  16. Polymer Coating of Carbon Nanotube Fibers for Electric Microcables.

    Science.gov (United States)

    Alvarez, Noe T; Ochmann, Timothy; Kienzle, Nicholas; Ruff, Brad; Haase, Mark R; Hopkins, Tracy; Pixley, Sarah; Mast, David; Schulz, Mark J; Shanov, Vesselin

    2014-11-04

    Carbon nanotubes (CNTs) are considered the most promising candidates to replace Cu and Al in a large number of electrical, mechanical and thermal applications. Although most CNT industrial applications require macro and micro size CNT fiber assemblies, several techniques to make conducting CNT fibers, threads, yarns and ropes have been reported to this day, and improvement of their electrical and mechanical conductivity continues. Some electrical applications of these CNT conducting fibers require an insulating layer for electrical insulation and protection against mechanical tearing. Ideally, a flexible insulator such as hydrogenated nitrile butadiene rubber (HNBR) on the CNT fiber can allow fabrication of CNT coils that can be assembled into lightweight, corrosion resistant electrical motors and transformers. HNBR is a largely used commercial polymer that unlike other cable-coating polymers such as polyvinyl chloride (PVC), it provides unique continuous and uniform coating on the CNT fibers. The polymer coated/insulated CNT fibers have a 26.54 μm average diameter-which is approximately four times the diameter of a red blood cell-is produced by a simple dip-coating process. Our results confirm that HNBR in solution creates a few microns uniform insulation and mechanical protection over a CNT fiber that is used as the electrically conducting core.

  17. Polymer Coating of Carbon Nanotube Fibers for Electric Microcables

    Directory of Open Access Journals (Sweden)

    Noe T. Alvarez

    2014-11-01

    Full Text Available Carbon nanotubes (CNTs are considered the most promising candidates to replace Cu and Al in a large number of electrical, mechanical and thermal applications. Although most CNT industrial applications require macro and micro size CNT fiber assemblies, several techniques to make conducting CNT fibers, threads, yarns and ropes have been reported to this day, and improvement of their electrical and mechanical conductivity continues. Some electrical applications of these CNT conducting fibers require an insulating layer for electrical insulation and protection against mechanical tearing. Ideally, a flexible insulator such as hydrogenated nitrile butadiene rubber (HNBR on the CNT fiber can allow fabrication of CNT coils that can be assembled into lightweight, corrosion resistant electrical motors and transformers. HNBR is a largely used commercial polymer that unlike other cable-coating polymers such as polyvinyl chloride (PVC, it provides unique continuous and uniform coating on the CNT fibers. The polymer coated/insulated CNT fibers have a 26.54 μm average diameter—which is approximately four times the diameter of a red blood cell—is produced by a simple dip-coating process. Our results confirm that HNBR in solution creates a few microns uniform insulation and mechanical protection over a CNT fiber that is used as the electrically conducting core.

  18. Smart Cellulose Fibers Coated with Carbon Nanotube Networks

    Directory of Open Access Journals (Sweden)

    Haisong Qi

    2014-11-01

    Full Text Available Smart multi-walled carbon nanotube (MWCNT-coated cellulose fibers with a unique sensing ability were manufactured by a simple dip coating process. The formation of electrically-conducting MWCNT networks on cellulose mono- and multi-filament fiber surfaces was confirmed by electrical resistance measurements and visualized by scanning electron microscopy. The interaction between MWCNT networks and cellulose fiber was investigated by Raman spectroscopy. The piezoresistivity of these fibers for strain sensing was investigated. The MWCNT-coated cellulose fibers exhibited a unique linear strain-dependent electrical resistance change up to 18% strain, with good reversibility and repeatability. In addition, the sensing behavior of these fibers to volatile molecules (including vapors of methanol, ethanol, acetone, chloroform and tetrahydrofuran was investigated. The results revealed a rapid response, high sensitivity and good reproducibility for these chemical vapors. Besides, they showed good selectivity to different vapors. It is suggested that the intrinsic physical and chemical features of cellulose fiber, well-formed MWCNT networks and favorable MWCNT-cellulose interaction caused the unique and excellent sensing ability of the MWCNT-coated cellulose fibers, which have the potential to be used as smart materials.

  19. Interaction of carbon nanotubes coatings with titanium substrate

    Science.gov (United States)

    Fraczek-Szczypta, Aneta; Wedel-Grzenda, Alicja; Benko, Aleksandra; Grzonka, Justyna; Mizera, Jaroslaw

    2017-02-01

    The aim of this study was to evaluate the impact of multi-walled carbon nanotubes (MWCNTs) after chemical surface functionalization on the interaction with a titanium surface. Two kinds of MWCNTs differing in terms of concentration of functional groups were deposited on the Ti surface using the electrophoretic deposition method (EPD). The study has shown the detailed analysis of the physicochemical properties of this form of carbon nanomaterial and received on their base coatings using various techniques, such as scanning electron microscopy (SEM), confocal microscopy, X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. The adhesion of the MWCNTs coatings to the Ti surface was determined using the shear test method, according to standard ASTM F-1044-05. These results indicated that one type of MWCNTs characterized by a higher concentration of functional groups has better adhesion to the metal surface than the second type. Analysis of the MWCNT-metal interface using Raman spectroscopy and SEM and STEM indicates the presence of phase built of MWCNT and TiO2. This phase could be a type of nanocomposite that affects the improvement of the adhesion of MWCNT to the Ti surface.

  20. Parylene coated carbon nanotube actuators for tactile stimulation

    Science.gov (United States)

    Bubak, Grzegorz; Ansaldo, Alberto; Gendron, David; Brayda, Luca; Ceseracciu, Luca; Ricci, Davide

    2015-04-01

    Ionic liquid/carbon nanotube based actuators have been constantly improved in recent years owing to their suitability for applications related to human-machine interaction and robotics thanks to their light-weight and low voltage operation. However, while great attention has been paid to the development of better electrodes and electrolytes, no adequate efforts were made to develop actuators to be used in direct contact with the human skin. Herein, we present our approach, based on the use of parylene-C coating. Indeed, owning to its physicochemical properties such as high dielectric strength, resistance to solvents, biological and chemical inactivity/inertness, parylene fulfils the requirements for use in biocompatible actuator fabrication. In this paper, we study the influence of the parylene coating on the actuator performance. To do so, we analyzed its mechanical and electrochemical properties. We looked into the role of parylene as a protection layer that can prevent alteration of the actuator performance likely caused by external conditions. In order to complete our study, we designed a haptic device and investigated the generated force, displacement and energy usage.

  1. Urea route to coat inorganic nanowires, carbon fibers and nanotubes by boron nitride

    Energy Technology Data Exchange (ETDEWEB)

    Gomathi, A.; Ramya Harika, M. [Chemistry and Physics of Materials Unit, DST Unit on Nanoscience and CSIR Centre of Excellence in Chemistry, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur P.O., Bangalore 560064 (India); Rao, C.N.R. [Chemistry and Physics of Materials Unit, DST Unit on Nanoscience and CSIR Centre of Excellence in Chemistry, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur P.O., Bangalore 560064 (India)], E-mail: cnrrao@jncasr.ac.in

    2008-03-15

    A simple route involving urea as the nitrogen source has been employed to carry out boron nitride coating on carbon fibers, multi-walled carbon nanotubes and inorganic nanowires. The process involves heating the carbon fibers and nanotubes or inorganic nanowires in a mixture of H{sub 3}BO{sub 3} and urea, followed by a heat treatment at 1000 deg. C in a N{sub 2} atmosphere. We have been able to characterize the BN coating by transmission electron microscopy as well as X-ray photoelectron spectroscopy. The urea decomposition route affords a simple method to coat boron nitride on one-dimensional nanostructures.

  2. Fabrication of barium/strontium carbonate coated amorphous carbon nanotubes as an improved field emitter

    Energy Technology Data Exchange (ETDEWEB)

    Maity, S. [Jadavpur University, Thin Film and Nanoscience Laboratory, Department of Physics, Kolkata (India); Jha, A.; Das, N.S. [Jadavpur University, School of Materials Science and Nanotechnology, Kolkata (India); Chattopadhyay, K.K. [Jadavpur University, Thin Film and Nanoscience Laboratory, Department of Physics, Kolkata (India); Jadavpur University, School of Materials Science and Nanotechnology, Kolkata (India)

    2013-02-15

    Amorphous carbon nanotubes (aCNTs) were synthesized by a chemical reaction between ferrocene and ammonium chloride at a temperature {proportional_to}250 {sup circle} C in an air furnace. As-synthesized aCNTs were coated with the barium/strontium carbonate through a simple chemical process. The coating of barium/strontium carbonate was confirmed by a high resolution transmission electron microscopy, X-ray diffraction, and Fourier transformed infrared spectroscopy. Morphology of the as-prepared samples was studied by field emission scanning electron microscopy. Thermal gravimetric analysis showed that barium/strontium carbonate coated aCNTs are more stable than the pristine aCNTs. As-prepared barium/strontium carbonate coated aCNTs showed significantly improved field emission properties with a turn-on field as low as 2.5 V/{mu}m. The variation of field emission characteristics of the barium/strontium carbonate coated aCNTs with interelectrode distances was also studied. (orig.)

  3. Magnetically Active and Coated Gadolinium-Filled Carbon Nanotubes

    KAUST Repository

    Fidiani, Elok

    2013-08-15

    Gd-filled carbon nanotubes (which include the so-called gadonanotubes(1)) have been attracting much interest due to their potential use in medical diagnostic applications. In the present work, a vacuum filling method was performed to confine gadolinium(III) iodide in carbon nanotubes (CNTs). Filling yields in excess of 50% were obtained. Cleaning and dosing of the external walls was undertaken, as well as the study of the filled CNT magnetic properties. Overall, we found that the encapsulating procedure can lead to reduction of the lanthanide metal and induce disorder in the initial GdI3-type structure. Notwithstanding, the magnetic response of the material is not compromised, retaining a strong paramagnetic response and an effective magnetic moment of similar to 6 mu B. Our results may entice further investigation into whether an analogous Gd3+ to Gd2+ reduction takes place in other Gd-filled CNT systems.

  4. Preparation and properties of in-situ growth of carbon nanotubes reinforced hydroxyapatite coating for carbon/carbon composites.

    Science.gov (United States)

    Liu, Shoujie; Li, Hejun; Su, Yangyang; Guo, Qian; Zhang, Leilei

    2017-01-01

    Carbon nanotubes (CNTs) possess excellent mechanical properties for their role playing in reinforcement as imparting strength to brittle hydroxyapatite (HA) bioceramic coating. However, there are few reports relating to the in-situ grown carbon nanotubes reinforced hydroxyapatite (CNTs-HA) coating. Here we demonstrate the potential application in reinforcing biomaterials by an attempt to use in-situ grown of CNTs strengthen HA coating, using a combined method composited of injection chemical vapor deposition (ICVD) and pulsed electrodeposition. The microstructure, phases and chemical compositions of CNTs-HA coatings were characterized by various advanced methods. The scanning electron microscopy (SEM) images indicated that CNTs-HA coatings avoided the inhomogeneous dispersion of CNTs inside HA coating. The result show that the interfacial shear strength between CNTs-HA coating and the C/C composite matrix reaches to 12.86±1.43MPa. Potenitodynamic polarization and electrochemical impedance spectroscopy (EIS) studies show that the content of CNTs affects the corrosion resistance of CNTs-HA coating. Cell culturing and simulated body fluid test elicit the biocompatibility with living cells and bioactivity of CNTs-HA coatings, respectively. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Field emission from entangled carbon nanotubes coated on/in a hollow metallic tube

    CERN Document Server

    Tokura, Y; Ohigashi, N; Akita, S; Nakayama, Y; Imasaki, K; Mima, K; Nakai, S

    2001-01-01

    Field emission properties of entangled carbon nanotubes were studied for an electron beam source of Cherenkov or Smith-Purcell free electron laser. The cathode was made of carbon nanotubes which were mixed with a very small amount of resin and coated on/in a hollow metallic tube with outer diameter of 0.5 mm. The emission current was as high as 2.2 mA with a fluctuation of <4%. It seems that some entangled nanotubes were frayed under the high electric field and then electrons were emitted mainly from their tips. Reduction of the work function of the carbon nanotubes was observed with the degradation of vacuum pressure in the experimental apparatus.

  6. Palladium-nanoparticle-coated carbon nanotube gas sensor

    Science.gov (United States)

    Han, Maeum; Jung, Daewoong; Lee, Gil S.

    2014-08-01

    Flexible hydrogen gas sensors were fabricated using multi-walled carbon nanotubes (MWCNTs) decorated with Pd nanoparticles for the detection of H2 gas at room temperature. A comparative gas-sensing study was carried out on both the Pd-nanoparticles-decorated and undecorated MWCNT sheets in order to examine the effect of Pd nanoparticles on the gas-sensing performances at room temperature. Experimental results showed that the MWCNTs/Pd sensor exhibited fast response and recovery as well as high sensitivity compared with the pure MWCNT sensor. The improved sensing properties of this sensor were attributed to the spillover effect of Pd nanoparticles and the highly conductive MWCNT sheet.

  7. Preparation and Application of Conductive Textile Coatings Filled with Honeycomb Structured Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Filip Govaert

    2014-01-01

    Full Text Available Electrical conductive textile coatings with variable amounts of carbon nanotubes (CNTs are presented. Formulations of textile coatings were prepared with up to 15 wt % of CNT, based on the solid weight of the binder. The binders are water based polyacrylate dispersions. The CNTs were mixed into the binder dispersion starting from a commercially available aqueous CNT dispersion that is compatible with the binder dispersion. Coating formulations with variable CNT concentrations were applied on polyester and cotton woven and knitted fabrics by different textile coating techniques: direct coating, transfer coating, and screen printing. The coatings showed increasing electrical conductivity with increasing CNT concentration. The coatings can be regarded to be electrically conductive (sheet resistivity<103 Ohm/sq starting at 3 wt% CNT. The degree of dispersion of the carbon nanotubes particles inside the coating was visualized by scanning electron microscopy. The CNT particles form honeycomb structured networks in the coatings, proving a high degree of dispersion. This honeycomb structure of CNT particles is forming a conductive network in the coating leading to low resistivity values.

  8. Pyrolytic-carbon coating in carbon nanotube foams for better performance in supercapacitors

    Science.gov (United States)

    He, Nanfei; Yildiz, Ozkan; Pan, Qin; Zhu, Jiadeng; Zhang, Xiangwu; Bradford, Philip D.; Gao, Wei

    2017-03-01

    Nowadays, the wide-spread adoption of supercapacitors has been hindered by their inferior energy density to that of batteries. Here we report the use of our pyrolytic-carbon-coated carbon nanotube foams as lightweight, compressible, porous, and highly conductive current collectors in supercapacitors, which are infiltrated with chemically-reduced graphene oxide and later compressed via mechanical and capillary forces to generate the active electrodes. The pyrolytic carbon coatings, introduced by chemical vapor infiltration, wrap around the CNT junctions and increase the surface roughness. When active materials are infiltrated, the pyrolytic-carbon coatings help prevent the π-stacking, enlarge the accessible surface area, and increase the electrical conductivity of the scaffold. Our best-performing device offers 48% and 57% higher gravimetric energy and power density, 14% and 23% higher volumetric energy and power density, respectively, and two times higher knee frequency, than the device with commercial current collectors, while the "true-performance metrics" are strictly followed in our measurements. We have further clarified the solution resistance, charge transfer resistance/capacitance, double-layer capacitance, and Warburg resistance in our system via comprehensive impedance analysis, which will shed light on the design and optimization of similar systems.

  9. Carbon nanotubes decorating methods

    OpenAIRE

    A.D. Dobrzańska-Danikiewicz; Łukowiec, D.; D. Cichock; W. Wolany

    2013-01-01

    Purpose: The work is to present and characterise various methods of depositing carbon nanotubes with nanoparticles of precious metals, and also to present the results of own works concerning carbon nanotubes coated with platinum nanoparticles.Design/methodology/approach: Electron transmission and scanning microscopy has been used for imaging the structure and morphology of the nanocomposites obtained and the distribution of nanoparticles on the surface of carbon nanotubes.Findings: The studie...

  10. Progammed synthesis of magnetic mesoporous silica coated carbon nanotubes for organic pollutant adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Tong, Yue; Zhang, Min, E-mail: congmingyang123@163.com; Xia, Peixiong; Wang, Linlin; Zheng, Jing; Li, Weizhen; Xu, Jingli, E-mail: xujingli@sues.edu.cn

    2016-05-15

    Magnetic mesoporous silica coated carbon nanotubes were produced from hydrophilic monodisperse magnetic nanoparticles decorated carbon nanotubes using well controlled programmed synthesis method and were characterized by TEM, XRD, FTIR, TGA, N{sub 2} adsorption–desorption and VSM. The well-designed mesoporous magnetic nanotubes had a large specific area, a highly open mesoporous structure and high magnetization. Firstly, SiO{sub 2}-coated maghemite/CNTs nanoparticles (CNTs/Fe{sub 3}O{sub 4}@SiO{sub 2} composites) were synthesized by the combination of high temperature decomposition process and an sol–gel method, in which the iron acetylacetonate as well as TEOS acted as the precursor for maghemite and SiO{sub 2}, respectively. The CNTs/Fe{sub 3}O{sub 4}@SiO{sub 2} composites revealed a core–shell structure, Then, CNTs/Fe{sub 3}O{sub 4}@mSiO{sub 2} was obtained by extracting cetyltrimethylammonium bromide (CTAB) via an ion-exchange procedure. The resulting composites show not only a magnetic response to an externally applied magnetic field, but also can be a good adsorbent for the organic pollutant in the ambient temperature. - Graphical abstract: Magnetic mesoporous silica coated carbon nanotubes were produced from hydrophilic monodisperse magnetic nanoparticles decorated carbon nanotubes using well controlled programmed synthesis, which can be a good adsorbent for the organic pollutant in the ambient temperature. - Highlights: • The surface of CNTs/Fe{sub 3}O{sub 4} is hydrophilic, which facilitates the silica coating. • The CNTs/Fe{sub 3}O{sub 4}@mSiO{sub 2} was synthesized by a facile method. • The CNTs/Fe{sub 3}O{sub 4}@mSiO{sub 2} can be a good adsorbent for the organic pollutant.

  11. Regrowth of Carbon Nanotubes Array on Al Layer Coated Substrate

    Directory of Open Access Journals (Sweden)

    Chien-Chao Chiu

    2010-01-01

    Full Text Available Carbon nanotube (CNT arrays have been synthesized by a repeated growth method using a custom-fabricated plasma-enhanced thermal chemical vapor deposition (PE-thermal CVD apparatus. The initial catalyst is a layered structure prepared by depositing 10 nm of Al followed by 3 nm of Fe on an oxidized silicon substrate. Following CNT growth, the CNT arrays are removed using an ultrasonic cleaner, and another CNT array is grown on the remaining Fe-Al bimetalic nanoparticles without the addition of more catalyst. Annealing the catalytic substrate in air between growth cycles results in the removal of residual amorphous carbon along with the CNTs, and oxidation of the Fe-Al nanoparticles. The diameter of CNTs is reduced with repeated growth-annealing cycles, an effect of which is attributed to the diminishing size of the catalytically active nanoparticles with each cycle. After two growth cycles, SWNTs with the extraordinarily narrow diameter of 0.86 nm are synthesized. The ID/IG ratio derived from the Raman spectrum of these of the SWNT arrays shows the remarkably low value of 0.22.

  12. ZnO-coated carbon nanotubes: inter-diffusion of carboxyl groups and enhanced photocurrent generation.

    Science.gov (United States)

    Hung, Chia-I; Wen, Hua-Chiang; Lai, Yao-Cheng; Chang, Shih-Hsin; Chou, Wu-Ching; Hsu, Wen-Kuang

    2015-03-16

    ZnO is a defect-governed oxide and emits light at both visible and UV regimes. This work employs atomic layer deposition to produce oxide particles on oxygenated carbon nanotubes, and the composites only show emission profiles at short wavelengths. The quenching of defect-related emissions at long wavelengths is verified, owing to carboxyl diffusion into oxygen vacancies, and doping is supported by ZnCO3 formation in oxide lattice. Fully coated tubes display an increased photocurrent and the quantum efficiency increases by 22 % relative to the bare nanotubes. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. CO2 sensing at room temperature using carbon nanotubes coated core fiber Bragg grating.

    Science.gov (United States)

    Shivananju, B N; Yamdagni, S; Fazuldeen, R; Sarin Kumar, A K; Hegde, G M; Varma, M M; Asokan, S

    2013-06-01

    The sensing of carbon dioxide (CO2) at room temperature, which has potential applications in environmental monitoring, healthcare, mining, biotechnology, food industry, etc., is a challenge for the scientific community due to the relative inertness of CO2. Here, we propose a novel gas sensor based on clad-etched Fiber Bragg Grating (FBG) with polyallylamine-amino-carbon nanotube coated on the surface of the core for detecting the concentrations of CO2 gas at room temperature, in ppm levels over a wide range (1000 ppm-4000 ppm). The limit of detection observed in polyallylamine-amino-carbon nanotube coated core-FBG has been found to be about 75 ppm. In this approach, when CO2 gas molecules interact with the polyallylamine-amino-carbon nanotube coated FBG, the effective refractive index of the fiber core changes, resulting in a shift in Bragg wavelength. The experimental data show a linear response of Bragg wavelength shift for increase in concentration of CO2 gas. Besides being reproducible and repeatable, the technique is fast, compact, and highly sensitive.

  14. Coating individual single-walled carbon nanotubes with nylon 6,10 through emulsion polymerization.

    Science.gov (United States)

    Chen, Wei-Chiang; Wang, Randy K; Ziegler, Kirk J

    2009-08-01

    Solvent microenvironments are formed around individual single-walled carbon nanotubes (SWNTs) by mixing SWNT suspensions with water-immiscible organic solvents. These microenvironments are used to encapsulate the SWNTs with the monomer sebacoyl chloride. Hexamethylene diamine is then injected into the aqueous phase so the formation of nylon 6,10 is restricted to the interface between the microenvironment and water. This emulsion polymerization process results in uniform coatings of nylon 6,10 around individual SWNTs. The nylon-coated SWNTs remain dispersed in the aqueous phase and are highly luminescent at pH values ranging from 3 to 12. This emulsion polymerization method provides a general approach to coat nanotubes with various polymers.

  15. Bump Bonding Using Metal-Coated Carbon Nanotubes

    Science.gov (United States)

    Lamb, James L.; Dickie, Matthew R.; Kowalczyk, Robert S.; Liao, Anna; Bronikowski, Michael J.

    2012-01-01

    Bump bonding hybridization techniques use arrays of indium bumps to electrically and mechanically join two chips together. Surface-tension issues limit bump sizes to roughly as wide as they are high. Pitches are limited to 50 microns with bumps only 8-14 microns high on each wafer. A new process uses oriented carbon nanotubes (CNTs) with a metal (indium) in a wicking process using capillary actions to increase the aspect ratio and pitch density of the connections for bump bonding hybridizations. It merges the properties of the CNTs and the metal bumps, providing enhanced material performance parameters. By merging the bumps with narrow and long CNTs oriented in the vertical direction, higher aspect ratios can be obtained if the metal can be made to wick. Possible aspect ratios increase from 1:1 to 20:1 for most applications, and to 100:1 for some applications. Possible pitch density increases of a factor of 10 are possible. Standard capillary theory would not normally allow indium or most other metals to be drawn into the oriented CNTs, because they are non-wetting. However, capillary action can be induced through the ability to fabricate oriented CNT bundles to desired spacings, and the use of deposition techniques and temperature to control the size and mobility of the liquid metal streams and associated reservoirs. This hybridization of two technologies (indium bumps and CNTs) may also provide for some additional benefits such as improved thermal management and possible current density increases.

  16. Beneficial effect of multi-wall carbon nanotubes on the graphitization of polyacrylonitrile (PAN coating

    Directory of Open Access Journals (Sweden)

    Mária Darányi

    2010-06-01

    Full Text Available Polyacrylonitrile (PAN solutions were deposited on quartz plates by spin coating to yield 2–3 µm thick PAN films. The films were decomposed at 1000°C in N2 atmosphere into electrically conducting carbonaceous coatings. When the precursor solution contained cobalt (0.2 g Co-acetate per 1 g PAN and/or multi-wall carbon nanotubes (MWCNTs, 2 mg MWCNT per 1 g PAN the specific electrical resistance of the product film dropped from the original 492 Ω·cm-1 value down to 46 Ω·cm-1. By excluding all other possibilities we came to the conclusion that the beneficial effect of carbon nanotubes is related to their catalytic action in the final graphitization of condensed nitrogen-containing rings into graphitic nanocrystallites.

  17. Ferromagnetic behaviour of polyaniline-coated multi-wall carbon nanotubes containing nickel nanoparticles

    Czech Academy of Sciences Publication Activity Database

    Konyushenko, Elena; Kazantseva, N. E.; Stejskal, Jaroslav; Trchová, Miroslava; Kovářová, Jana; Sapurina, I.; Tomishko, M. M.

    2008-01-01

    Roč. 320, 3-4 (2008), s. 231-240 ISSN 0304-8853 R&D Projects: GA AV ČR IAA4050313; GA AV ČR IAA400500504; GA MŠk ME 847; GA ČR GA202/06/0419 Institutional research plan: CEZ:AV0Z40500505 Keywords : multi-wall carbon nanotube * conducting polymer * polyaniline coating Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.283, year: 2008

  18. Carbon nanotube-coating accelerated cell adhesion and proliferation on poly (L-lactide)

    Energy Technology Data Exchange (ETDEWEB)

    Hirata, Eri, E-mail: erieri@den.hokudai.ac.jp [Graduate School of Dental Medicine, Hokkaido University, Sapporo (Japan); Akasaka, Tsukasa [Graduate School of Dental Medicine, Hokkaido University, Sapporo (Japan); Uo, Motohiro [Graduate School of Medical and Dental Science, Tokyo Medical and Dental University, Tokyo (Japan); Takita, Hiroko; Watari, Fumio; Yokoyama, Atsuro [Graduate School of Dental Medicine, Hokkaido University, Sapporo (Japan)

    2012-12-01

    Highlights: Black-Right-Pointing-Pointer The surface of a polylactic acid (PLLA) was coated multiwalled carbon nanotubes (MWCNTs). Black-Right-Pointing-Pointer MWCNT-coated PLLA showed remarkable higher wettability than uncoated PLLA. Black-Right-Pointing-Pointer More Human osteosarcoma cell line (Saos2) adhered on the CNT-coated than those on uncoated PLLA at 2 h after seeding. Black-Right-Pointing-Pointer MWCNT-coating on PLLA improved the surface wettability and initial cell attachment at early stage. - Abstract: The surface of a polylactic acid (PLLA) was coated multiwalled carbon nanotubes (MWCNTs) in order to improve the surface properties. In addition, its surface characteristics and cell culturing properties were examined. Whole surface of PLLA was homogeneously covered by MWCNTs maintained a unique tubular structure. MWCNT-coated PLLA showed remarkable higher wettability than uncoated PLLA. Human osteosarcoma cell line (Saos2) adhered well on the CNT-coated PLLA whereas there are few cells attached on the uncoated PLLA at 2 h after seeding. The number of the cells on uncoated PLLA was still smaller than on the MWCNT-coated PLLA at 1 and 3 days. Moreover, The DNA content in the cells attached to the MWCNT-coated PLLA was significantly higher than that on the uncoated PLLA (p < 0.05) at 1 and 3 days. There was no significant difference between the scaffolds for ALP activity normalized by DNA content at both term (p > 0.1). Therefore MWCNT-coating on PLLA improved the surface wettability and initial cell attachment at early stage.

  19. Switchable surfactant-assisted carbon nanotube coatings: Innovation through pH shift

    Directory of Open Access Journals (Sweden)

    Carlos eSanchís

    2015-01-01

    Full Text Available The inner surface of fused silica capillaries has been coated with a dense/homogeneous coating of commercial multi-wall carbon nanotubes (MWCNTs using a stable ink as deposit precursor. Solubilization of the MWCNTs was achieved in water/ethanol/dimethylformamide by the action of a surfactant which can switch between a neutral or an ionic form depending on the pH of the medium, which thus becomes the driving force for the entire deposition process. Careful control of the experimental conditions have allowed us to selectively deposit CNTs on the inner surface of insulating silica capillaries by a simple, reproducible, and easily adaptable method.

  20. Surfactant-coated single-walled carbon nanotubes as a novel pseudostationary phase in capillary EKC.

    Science.gov (United States)

    Suárez, Beatriz; Simonet, Bartolomé M; Cárdenas, Soledad; Valcárcel, Miguel

    2007-06-01

    The analytical potential of the use of surfactant-coated single-walled carbon nanotubes (SC-SWNTs) as pseudostationary phase in CE is described. The pseudostationary phase shows an efficient alternative in enhancing electrochromatographic resolution of compounds which are capable of interacting with a nanotube surface, such as aromatic compounds. In general, the resolution is enhanced by increasing nanotube concentration in the buffer but the maximum amount of SWNTs that can be added to background electrolyte was found limited by compatibility with the UV/visible detection. As an alternative, a low-extension partial filling was used, consisting of the introduction into the capillary of concentrated SC-SWNT, just before the sample, with a plug length similar to the sample one. This has been showed as a reliable procedure in increasing resolution and sensitivity by sweeping phenomena. Finally, the potential of SC-SWNTs to perform chiral separations is discussed.

  1. Single-walled carbon nanotubes coated with ZnO by atomic layer deposition

    Science.gov (United States)

    Pal, Partha P.; Gilshteyn, Evgenia; Jiang, Hua; Timmermans, Marina; Kaskela, Antti; Tolochko, Oleg V.; Kurochkin, Alexey V.; Karppinen, Maarit; Nisula, Mikko; Kauppinen, Esko I.; Nasibulin, Albert G.

    2016-12-01

    The possibility of ZnO deposition on the surface of single-walled carbon nanotubes (SWCNTs) with the help of an atomic layer deposition (ALD) technique was successfully demonstrated. The utilization of pristine SWCNTs as a support resulted in a non-uniform deposition of ZnO in the form of nanoparticles. To achieve uniform ZnO coating, the SWCNTs first needed to be functionalized by treating the samples in a controlled ozone atmosphere. The uniformly ZnO coated SWCNTs were used to fabricate UV sensing devices. An UV irradiation of the ZnO coated samples turned them from hydrophobic to hydrophilic behaviour. Furthermore, thin films of the ZnO coated SWCNTs allowed us switch p-type field effect transistors made of pristine SWCNTs to have ambipolar characteristics.

  2. Synthesis and Photocatalytic Activity of Anatase TiO2 Nanoparticles-coated Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Xie Yi

    2009-01-01

    Full Text Available Abstract A simple and straightforward approach to prepare TiO2-coated carbon nanotubes (CNTs is presented. Anatase TiO2 nanoparticles (NPs with the average size ~8 nm were coated on CNTs from peroxo titanic acid (PTA precursor even at low temperature of 100 °C. We demonstrate the effects of CNTs/TiO2 molar ratio on the adsorption capability and photocatalytic efficiency under UV–visible irradiation. The samples showed not only good optical absorption in visible range, but also great adsorption capacity for methyl orange (MO dye molecules. These properties facilitated the great enhancement of photocatalytic activity of TiO2 NPs-coated CNTs photocatalysts. The TiO2 NPs-coated CNTs exhibited 2.45 times higher photocatalytic activity for MO degradation than that of pure TiO2.

  3. A novel processing of carbon nanotubes grown on molecular sieve coated porous ceramics

    Science.gov (United States)

    Mazumder, Sangram; Sarkar, Naboneeta; Park, Jung Gyu; Zhao, Wei; Kim, Sukyoung; Kim, Ik Jin

    2015-08-01

    The present study focuses on the growth of carbon nanotubes (CNTs) on Fe-containing zeolites coated porous ceramics by implementing three different and independent techniques, successively. Direct foaming-derived porous ceramics were subjected to hydrothermal reaction for on-site growth of NaA zeolites within it. The porous ceramics-zeolite composite was subjected to ion-exchange reaction to obtain the catalyst for CNT synthesis. Multi-walled CNTs (MWCNTs) were grown by catalytic chemical vapour deposition (CCVD) process using acetylene as carbon source. Microstructural, thermogravimetric and spectroscopic analyses showed distinctive differences in terms of hollow structural feature, yield and crystallinity of the MWCNTs with different reaction temperatures.

  4. Influence of carbon nanotubes coatings onto carbon fiber by oxidative treatments combined with electrophoretic deposition on interfacial properties of carbon fiber composite

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Chao; Jiang, Jianjun, E-mail: jianjun@nwpu.edu.cn; Liu, Fa; Fang, Liangchao; Wang, Junbiao; Li, Dejia; Wu, Jianjun

    2015-12-01

    Graphical abstract: Carbon nanotube/carbon fiber hybrid fiber was proposed by the treatment with hydrogen peroxide and concentrated nitric acid combined with electrophoretic deposition process. - Highlights: • Carbon nanotube coated carbon fiber was prepared by two methods. • Uniform and dense CNTs network formed by oxidative treatments combined with EPD. • Pretreatment of the CF is beneficial to EPD of CNTs on carbon fiber surface. • CNTs enhanced the surface activity and wettability of carbon fibers. • CNTs have contributed to the interfacial properties of composite. - Abstract: To improve the interfacial performance of carbon fiber (CF) and epoxy resin, carbon nanotubes (CNTs) coatings were utilized to achieve this purpose through coating onto CF by the treatment with hydrogen peroxide and concentrated nitric acid combined with electrophoretic deposition (EPD) process. The influence of electrophoretically deposited CNTs coatings on the surface properties of CFs were investigated by Fourier transform infrared spectrometer, atomic force microscopy, scanning electron microscopy and dynamic contact angle analysis. The results indicated that the deposition of carbon nanotubes introduced some polar groups to carbon fiber surfaces, enhanced surface roughness and changed surface morphologies of carbon fibers. Surface wettability of carbon fibers may be significantly improved by increasing surface free energy of the fibers due to the deposition of CNTs. The thickness and density of the coatings increases with the introduction of pretreatment of the CF during the EPD process. Short beam shear test was performed to examine the effect of carbon fiber functionalization on mechanical properties of the carbon fiber/epoxy resin composites. The interfacial adhesion of CNTs/CF reinforced epoxy composites showed obvious enhancement of interlaminar shear strength by 60.2% and scanning electron microscope photographs showed that the failure mode of composites was changed

  5. Carbon-coated SnO2 nanotubes: template-engaged synthesis and their application in lithium-ion batteries.

    Science.gov (United States)

    Wu, Ping; Du, Ning; Zhang, Hui; Yu, Jingxue; Qi, Yue; Yang, Deren

    2011-02-01

    This paper reports the synthesis of carbon-coated SnO2 (SnO2-C) nanotubes through a simple glucose hydrothermal and subsequent carbonization approach by using Sn nanorods as sacrificial templates. The as-synthesized SnO2-C nanotubes have been applied as anode materials for lithium-ion batteries, which exhibit improved cyclic performance compared to pure SnO2 nanotubes. The hollow nanostructure, together with the carbon matrix which has good buffering effect and high electronic conductivity, can be responsible for the improved cyclic performance.

  6. Mechanical characterization of copper coated carbon nanotubes reinforced aluminum matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Maqbool, Adnan, E-mail: adnanmaqbool247@gmail.com [Faculty of Materials Science and Engineering, GIK Institute of Engineering Sciences and Technology, Topi 23640, KP (Pakistan); School of Nano and Advanced Material Engineering, Changwon National University, Gyeongnam 641-773 (Korea, Republic of); Hussain, M. Asif; Khalid, F. Ahmad; Bakhsh, Nabi [Faculty of Materials Science and Engineering, GIK Institute of Engineering Sciences and Technology, Topi 23640, KP (Pakistan); Hussain, Ali; Kim, Myong Ho [School of Nano and Advanced Material Engineering, Changwon National University, Gyeongnam 641-773 (Korea, Republic of)

    2013-12-15

    In this investigation, carbon nanotube (CNT) reinforced aluminum composites were prepared by the molecular-level mixing process using copper coated CNTs. The mixing of CNTs was accomplished by ultrasonic mixing and ball milling. Electroless Cu-coated CNTs were used to enhance the interfacial bonding between CNTs and aluminum. Scanning electron microscope analysis revealed the homogenous dispersion of Cu-coated CNTs in the composite samples compared with the uncoated CNTs. The samples were pressureless sintered under vacuum followed by hot rolling to promote the uniform microstructure and dispersion of CNTs. In 1.0 wt.% uncoated and Cu-coated CNT/Al composites, compared to pure Al, the microhardness increased by 44% and 103%, respectively. As compared to the pure Al, for 1.0 wt.% uncoated CNT/Al composite, increase in yield strength and ultimate tensile strength was estimated about 58% and 62%, respectively. However, in case of 1.0 wt.% Cu-coated CNT/Al composite, yield strength and ultimate tensile strength were increased significantly about 121% and 107%, respectively. - Graphical Abstract: Copper coated CNTs were synthesized by the electroless plating process. Optimizing the plating bath to (1:1) by wt CNTs with Cu, thickness of Cu-coated CNTs has been reduced to 100 nm. Cu-coated CNTs developed the stronger interfacial bonding with the Al matrix which resulted in the efficient transfer of load. Highlights: • Copper coated CNTs were synthesized by the electroless plating process. • Thickness of Cu-coated CNTs has been reduced to 100 nm by optimized plating bath. • In 1.0 wt.% Cu-coated CNT/Al composite, microhardness increased by 103%. • Cu-coated CNTs transfer load efficiently with stronger interfacial bonding. • In 1.0 wt.% Cu-coated CNT/Al composite, Y.S and UTS increased by 126% and 105%.

  7. Steam purification for the removal of graphitic shells coating catalytic particles and the shortening of single-walled carbon nanotubes.

    Science.gov (United States)

    Ballesteros, Belén; Tobias, Gerard; Shao, Lidong; Pellicer, Eva; Nogués, Josep; Mendoza, Ernest; Green, Malcolm L H

    2008-09-01

    Purification and shortening of single-walled carbon nanotubes (SWNTs) is carried out by treatment with steam. During the steam purification the graphitic shells coating the catalytic metal particles are removed. Consequently, the exposed catalytic particles can be easily dissolved by treatment with hydrochloric acid. No damage to the carbon nanotube tubular structure is observed, even after prolonged treatment with steam. Samples are characterized by HRTEM, TGA, magnetic measurements, Raman spectroscopy, AFM, and XPS.

  8. Glassy carbon electrode coated with polyaniline-functionalized carbon nanotubes for detection of trace lead in acetate solution

    Energy Technology Data Exchange (ETDEWEB)

    Wang Zhaomeng; Liu Erjia, E-mail: mejliu@ntu.edu.sg; Gu Donghao; Wang Yongsheng

    2011-05-31

    The performance of glassy carbon electrodes (GCEs) coated with polyaniline-multiwalled carbon nanotube (MWCNT-CO-PANI) nanocomposite coatings was investigated in detection of Pb{sup 2+} ions in a 0.1 M acetate buffer solution using square wave anodic stripping voltammetry (SWASV). It was found that the MWCNT-CO-PANI coated electrodes had a better performance than the bare GCEs. Different solvents were used to get a better dispersion of MWCNTs in the PANI matrix for higher stripping signals. The surface morphology and structure of the coated electrodes were examined using field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and micro Raman spectroscopy, showing that the conductive PANI matrix worked as both a conductor to electrically connect the individual MWCNTs, and a binder to mechanically join the MWCNTs.

  9. Bioinspired and biocompatible carbon nanotube-Ag nanohybrid coatings for robust antibacterial applications.

    Science.gov (United States)

    Nie, Chuanxiong; Yang, Ye; Cheng, Chong; Ma, Lang; Deng, Jie; Wang, Lingren; Zhao, Changsheng

    2017-03-15

    The design of self-sterilizing surfaces with favorable biocompatibility is acknowledged as an effective approach to deal with the bacterial infections of biomedical devices. In this study, we report an intriguing protocol for the large-scale fabrication of self-sterilizing and biocompatible surface film coatings by using polymer shielded silver nanoparticle loaded oxidized carbon nanotube (AgNPs@oCNT) nano-dispersions. To achieve the antibacterial coatings, the bioinspired positively charged and negatively charged AgNPs@oCNTs were alternately deposited onto substrates by spray-coating assisted layer-by-layer assembly. Then the bacterial inhibitory zones, optical density value monitoring, bacterial killing efficiency and adhesion were investigated; and all the results revealed that the AgNPs@oCNTs thin film coatings exhibited robust and long-term antibacterial activity against both Gram negative and Gram positive bacteria. Moreover, due to the shielding effects of polymer layers, the coatings showed extraordinary blood compatibility and limited toxicity against human umbilical vein endothelial cells. It is believed that the proposed large-scale fabrication of bactericidal, blood and cell compatible AgNPs@oCNT based thin film coatings will have great potential to forward novel operational pathogenic inhibition strategies to avoid undesired bacterial contaminations of biomedical implants or biological devices. Bacterial infection of medical devices has been considered to be a world-wide clinical threat towards patients' health. In this study, a bioinspired and biocompatible antibacterial coating was prepared via the spray-assisted layer-by-layer (LbL) assembly. The silver nanopartilces loaded oxidized carbon nanotube (AgNPs@oCNT), which were coated by functional polymers (chitosan and synthetic heparin mimicking polymers), were prepared via mussel inspired chemistry; and the spray-assisted assembly process allowed the fast construction on devices. Owing to the

  10. Evaluation of Different Single-Walled Carbon Nanotube Surface Coatings for Single-Particle Tracking Applications in Biological Environments.

    Science.gov (United States)

    Gao, Zhenghong; Danné, Noémie; Godin, Antoine Guillaume; Lounis, Brahim; Cognet, Laurent

    2017-11-16

    Fluorescence imaging of biological systems down to the single-molecule level has generated many advances in cellular biology. For applications within intact tissue, single-walled carbon nanotubes (SWCNTs) are emerging as distinctive single-molecule nanoprobes, due to their near-infrared photoluminescence properties. For this, SWCNT surfaces must be coated using adequate molecular moieties. Yet, the choice of the suspension agent is critical since it influences both the chemical and emission properties of the SWCNTs within their environment. Here, we compare the most commonly used surface coatings for encapsulating photoluminescent SWCNTs in the context of bio-imaging applications. To be applied as single-molecule nanoprobes, encapsulated nanotubes should display low cytotoxicity, and minimal unspecific interactions with cells while still being highly luminescent so as to be imaged and tracked down to the single nanotube level for long periods of time. We tested the cell proliferation and cellular viability of each surface coating and evaluated the impact of the biocompatible surface coatings on nanotube photoluminescence brightness. Our study establishes that phospholipid-polyethylene glycol-coated carbon nanotube is the best current choice for single nanotube tracking experiments in live biological samples.

  11. Preparation and Photocatalytic Properties of SnO2 Coated on Nitrogen-Doped Carbon Nanotubes

    OpenAIRE

    Lingling Wang; Long Shen; Luping Zhu; Haiying Jin; Naici Bing; Lijun Wang

    2012-01-01

    SnO2 nanoparticles coated on nitrogen-doped carbon nanotubes were prepared successfully via a simple wet-chemical route. The as-obtained SnO2/CNx composites were characterized using X-ray powder diffraction, scanning electron microscopy, and transmission electron microscopy. The photocatalytic activity of as-prepared SnO2/CNx for degradation Rhodamine B under UV light irradiation was investigated. The results show that SnO2/CNx nanocomposites have a higher photocatalytic activity than pure Sn...

  12. Coatings of Different Carbon Nanotubes on Platinum Electrodes for Neuronal Devices: Preparation, Cytocompatibility and Interaction with Spiral Ganglion Cells.

    Directory of Open Access Journals (Sweden)

    Niklas Burblies

    Full Text Available Cochlear and deep brain implants are prominent examples for neuronal prostheses with clinical relevance. Current research focuses on the improvement of the long-term functionality and the size reduction of neural interface electrodes. A promising approach is the application of carbon nanotubes (CNTs, either as pure electrodes but especially as coating material for electrodes. The interaction of CNTs with neuronal cells has shown promising results in various studies, but these appear to depend on the specific type of neurons as well as on the kind of nanotubes. To evaluate a potential application of carbon nanotube coatings for cochlear electrodes, it is necessary to investigate the cytocompatibility of carbon nanotube coatings on platinum for the specific type of neuron in the inner ear, namely spiral ganglion neurons. In this study we have combined the chemical processing of as-delivered CNTs, the fabrication of coatings on platinum, and the characterization of the electrical properties of the coatings as well as a general cytocompatibility testing and the first cell culture investigations of CNTs with spiral ganglion neurons. By applying a modification process to three different as-received CNTs via a reflux treatment with nitric acid, long-term stable aqueous CNT dispersions free of dispersing agents were obtained. These were used to coat platinum substrates by an automated spray-coating process. These coatings enhance the electrical properties of platinum electrodes, decreasing the impedance values and raising the capacitances. Cell culture investigations of the different CNT coatings on platinum with NIH3T3 fibroblasts attest an overall good cytocompatibility of these coatings. For spiral ganglion neurons, this can also be observed but a desired positive effect of the CNTs on the neurons is absent. Furthermore, we found that the well-established DAPI staining assay does not function on the coatings prepared from single-wall nanotubes.

  13. Final Technical Report CONDUCTIVE COATINGS FOR SOLAR CELLS USING CARBON NANOTUBES

    Energy Technology Data Exchange (ETDEWEB)

    Paul J Glatkowski; Jorma Peltola; Christopher Weeks; Mike Trottier; David Britz

    2007-09-30

    US Department of Energy (DOE) awarded a grant for Eikos Inc. to investigate the feasibility of developing and utilizing Transparent Conducting Coatings (TCCs) based on carbon nanotubes (CNT) for solar cell applications. Conventional solar cells today employ metal oxide based TCCs with both Electrical Resistivity (R) and Optical Transparency (T), commonly referred to as optoelectronic (RT) performance significantly higher than with those possible with CNT based TCCs available today. Transparent metal oxide based coatings are also inherently brittle requiring high temperature in vacuum processing and are thus expensive to manufacture. One such material is indium tin oxide (ITO). Global demand for indium has recently increased rapidly while supply has diminished causing substantial spikes in raw material cost and availability. In contrast, the raw material, carbon, needed for CNT fabrication is abundantly available. Transparent Conducting Coatings based on CNTs can overcome not only cost and availability constraints while also offering the ability to be applied by existing, low cost process technologies under ambient conditions. Processes thus can readily be designed both for rigid and flexible PV technology platforms based on mature spray or dip coatings for silicon based solar cells and continuous roll to roll coating processes for polymer solar applications.

  14. Fabrication and Characterization of Multi-Walled Carbon Nanotube (MWCNT) and Ni-Coated Multi-Walled Carbon Nanotube (Ni-MWCNT) Repair Patches for Carbon Fiber Reinforced Composite Systems

    Science.gov (United States)

    Johnson, Brienne; Caraccio, Anne; Tate, LaNetra; Jackson, Dionne

    2011-01-01

    Multi-walled carbon nanotube (MWCNT)/epoxy and nickel-coated multi-walled carbon nanotube (Ni-MWCNT)/epoxy systems were fabricated into carbon fiber composite repair patches via vacuum resin infusion. Two 4 ply patches were manufactured with fiber orientations of [90/ 90/ 4590] and [0/90/ +45/ -45]. Prior to resin infusion, the MWCNT/Epoxy system and NiMWCNT/ epoxy systems were optimized for dispersion quality. Scanning electron microscopy (SEM) and optical microscopy (OM) were used to determine the presence ofcarbon nanotubes and assess dispersion quality. Decomposition temperatures were determined via thermogravametric analysis (TGA). SEM and TGA were also used to evaluate the composite repair patches.

  15. Silica-coated multi-walled carbon nanotubes impregnated with polyethyleneimine for carbon dioxide capture under the flue gas condition

    Science.gov (United States)

    Lee, Min-Sang; Park, Soo-Jin

    2015-03-01

    In this study, silica-coated multi-walled carbon nanotubes impregnated with polyethyleneimine (PEI) were prepared via a two-step process: (i) hydrolysis of tetraethylorthosilicate onto multi-walled carbon nanotubes, and (ii) impregnation of PEI. The adsorption properties of CO2 were investigated using CO2 adsorption-desorption isotherms at 298 K and thermogravimetric analysis under the flue gas condition (15% CO2/85% N2). The results obtained in this study indicate that CO2 adsorption increases after impregnation of PEI. The increase in CO2 capture was attributed to the affinity between CO2 and the amine groups. CO2 adsorption-desorption experiments, which were repeated five times, also showed that the prepared adsorbents have excellent regeneration properties.

  16. Multi-Walled Carbon Nanotube-Assisted Electrodeposition of Silver Dendrite Coating as a Catalytic Film

    Directory of Open Access Journals (Sweden)

    Li Fu

    2017-12-01

    Full Text Available A multi-walled carbon nanotube (MWCNT-coated indium tin oxide (ITO slide was used as a platform for the growth of a silver dendrite (Ag-D film using cyclic voltammetry. The particular dendritic nanostructures were formed by the diffusion-limited-aggregation model due to the potential difference between the MWCNTs and the ITO surface. The Ag-D-coated ITO film was then used for the catalytic degradation of methyl orange (MO and methylene blue (MB under static aqueous conditions. The network structure of the Ag-D allows the efficient diffusion of MO and MB, and consequently enhances the catalytic performance. Since the thin film is much easier to use for the post-treatment of powder catalysts, the proposed method shows great potential in many catalytic applications.

  17. Dynamic Response of Tapered Optical Multimode Fiber Coated with Carbon Nanotubes for Ethanol Sensing Application

    Directory of Open Access Journals (Sweden)

    Arafat Shabaneh

    2015-05-01

    Full Text Available Ethanol is a highly combustible chemical universally designed for biomedical applications. In this paper, optical sensing performance of tapered multimode fiber tip coated with carbon nanotube (CNT thin film towards aqueous ethanol with different concentrations is investigated. The tapered optical multimode fiber tip is coated with CNT using drop-casting technique and is annealed at 70 °C to enhance the binding of the nanomaterial to the silica fiber tip. The optical fiber tip and the CNT sensing layer are micro-characterized using FESEM and Raman spectroscopy techniques. When the developed sensor was exposed to different concentrations of ethanol (5% to 80%, the sensor reflectance reduced proportionally. The developed sensors showed high sensitivity, repeatability and fast responses (<55 s towards ethanol.

  18. High Sensitivity Carbon Nanotubes Flow-Rate Sensors and Their Performance Improvement by Coating

    Directory of Open Access Journals (Sweden)

    Xing Yang

    2010-05-01

    Full Text Available A new type of hot-wire flow-rate sensor (HWFS with a sensing element made of a macro-sized carbon nanotube (CNT strand is presented in this study. An effective way to improve repeatability of the CNT flow-rate sensor by coating a layer of Al2O3 on the CNT surface is proposed. Experimental results show that due to the large surface-to-volume ratio and thin coated Al2O3 layer, the CNT flow-rate sensor has higher sensitivity and faster response than a conventional platinum (Pt HWFS. It is also demonstrated that the covered CNT flow-rate sensor has better repeatability than its bare counterpart due to insulation from the surrounding environment. The proposed CNT flow-rate sensor shows application potential for high-sensitivity measurement of flow rate.

  19. Carbon Nanotube Composite Electrode Coated with Polypyrrole for Microbial Fuel Cell Application.

    Science.gov (United States)

    Roh, Sung-Hee; Woo, Hee-Gweon

    2015-01-01

    Microbial fuel cells (MFCs) are bio-electrochemical system that can convert biomass spontaneously into electricity through the metabolic activity of microorganisms. We constructed MFCs of polypyrrole (PPy) coated carbon nanotube (CNT) composite as an electrode material and Shewanella oneidensis as the biocatalyst to increase power density. The PPy-coated CNT were synthesized by the in-situ chemical polymerization of pyrrole on CNT, and the electrochemical properties and performance of the modified electrode as an anode in MFC were then investigated. Treatment with 0.1 wt% Ge-132 on the acid-treated MWNTs helped to form better PPy-MWNT composite. The PPy-CNT/CF anode showed a noteworthy 38% power production improvement when compared to plain CF anode. The PPy-CNT composite could be a very efficient and promising electrode material for electricity generation of MFC.

  20. Chitosan/silica coated carbon nanotubes composite proton exchange membranes for fuel cell applications.

    Science.gov (United States)

    Liu, Hai; Gong, Chunli; Wang, Jie; Liu, Xiaoyan; Liu, Huanli; Cheng, Fan; Wang, Guangjin; Zheng, Genwen; Qin, Caiqin; Wen, Sheng

    2016-01-20

    Silica-coated carbon nanotubes (SCNTs), which were obtained by a simple sol-gel method, were utilized in preparation of chitosan/SCNTs (CS/SCNTs) composite membranes. The thermal and oxidative stability, morphology, mechanical properties, water uptake and proton conductivity of CS/SCNTs composite membranes were investigated. The insulated and hydrophilic silica layer coated on CNTs eliminates the risk of electronic short-circuiting and enhances the interaction between SCNTs and chitosan to ensure the homogenous dispersion of SCNTs, although the water uptake of CS/SCNTs membranes is reduced owing to the decrease of the effective number of the amino functional groups of chitosan. The CS/SCNTs composite membranes are superior to the pure CS membrane in thermal and oxidative stability, mechanical properties and proton conductivity. The results of this study suggest that CS/SCNTs composite membranes exhibit promising potential for practical application in proton exchange membranes. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. High Sensitivity Carbon Nanotubes Flow-Rate Sensors and Their Performance Improvement by Coating

    Science.gov (United States)

    Yang, Xing; Zhou, Zhaoying; Wang, Dingqu; Liu, Xiaoli

    2010-01-01

    A new type of hot-wire flow-rate sensor (HWFS) with a sensing element made of a macro-sized carbon nanotube (CNT) strand is presented in this study. An effective way to improve repeatability of the CNT flow-rate sensor by coating a layer of Al2O3 on the CNT surface is proposed. Experimental results show that due to the large surface-to-volume ratio and thin coated Al2O3 layer, the CNT flow-rate sensor has higher sensitivity and faster response than a conventional platinum (Pt) HWFS. It is also demonstrated that the covered CNT flow-rate sensor has better repeatability than its bare counterpart due to insulation from the surrounding environment. The proposed CNT flow-rate sensor shows application potential for high-sensitivity measurement of flow rate. PMID:22399913

  2. Molecular dynamics study of effects of nickel coating on torsional behavior of single-walled carbon nanotube

    Energy Technology Data Exchange (ETDEWEB)

    Song Haiyang, E-mail: gsfshy@sohu.co [School of Science, Xi' an University of Posts and Telecommunications, Xi' an 710121 (China); Zha Xinwei [School of Science, Xi' an University of Posts and Telecommunications, Xi' an 710121 (China)

    2011-02-15

    The effects of nickel coating on the torsional behaviors of single-walled carbon nanotubes (SWCNTs) subject to torsion motion are investigated using the molecular dynamics (MD) simulation method. The simulation results show that regardless of chirality, defect or radius, nickel coating can considerably enhance the critical torque of SWCNTs. However, by comparing the critical torsion angle between nickel-coated SWCNTs and corresponding pristine SWCNTs, it is found that nickel coating in small-radius nanotubes does induce a reduction in the critical torsion angle. The results also show that the structural failure of nickel coated imperfect (9,0) SWCNT occurs at an obviously higher critical torque in comparison with uncoated (9,0) SWCNT with a vacancy defect. Furthermore, we also find that the critical torque of a short nickel coated SWCNT is bigger than that of a long one, while the critical torsion angle for a short tube is smaller than that for a long one.

  3. Carbon nanotube-coated solid-phase microextraction metal fiber based on sol-gel technique.

    Science.gov (United States)

    Jiang, Ruifen; Zhu, Fang; Luan, Tiangang; Tong, Yexiang; Liu, Hong; Ouyang, Gangfeng; Pawliszyn, Janusz

    2009-05-29

    A novel carbon nanotube (CNT)-coated solid-phase microextraction fiber was prepared based on sol-gel technique. Commonly used fragile fused silica fiber was replaced with stainless steel wire, which made the fiber unbreakable. An approach was also proposed for batch producing, and good reproducibilities for fiber to fiber and between fibers were achieved. Experiments showed that the sol-gel-CNT fiber exhibited high thermal stability to resist 350 degrees C and excellent solvent durability in methanol and acetonitrile. Compared to commercial polydimethylsiloxane (PDMS) fiber, the sol-gel-CNT fiber represented significantly improved extraction efficiencies for both polar (phenols) and non-polar (benzene, toluene, ethylbenzene, and o-xylene) compounds. Meanwhile, no replacement effect, low carry-over and wide linear range demonstrated that the newly prepared sol-gel-CNT coating has liquid properties, which allow a relatively easy quantification procedure. Moreover, the characterization of the sol-gel-CNT coating was also evaluated with McReynold probe solutes. The results showed that the coating has better affinity for all the five types of solutes compared to commercial 7microm PDMS fiber, which suggested that the coating has the potential to be developed as GC stationary phase.

  4. Microwave synthesis and characterisation of tin dioxide (SnO2) coated multi-walled carbon nanotubes

    CSIR Research Space (South Africa)

    Motshekga, S

    2010-09-01

    Full Text Available Metal nanoparticles coated onto carbon nanotubes (CNTs) provide a way to obtain novel materials with useful properties for gas sensing and catalyst application. Metal oxides are well-known materials suitable for detecting a wide spectrum of gases...

  5. Improved tensile and buckling behavior of defected carbon nanotubes utilizing boron nitride coating – A molecular dynamic study

    Energy Technology Data Exchange (ETDEWEB)

    Badjian, H.; Setoodeh, A.R., E-mail: setoodeh@sutech.ac.ir

    2017-02-15

    Synthesizing inorganic nanostructures such as boron nitride nanotubes (BNNTs) have led to immense studies due to their many interesting functional features such as piezoelectricity, high temperature resistance to oxygen, electrical insulation, high thermal conductivity and very long lengths as physical features. In order to utilize the superior properties of pristine and defected carbon nanotubes (CNTs), a hybrid nanotube is proposed in this study by forming BNNTs surface coating on the CNTs. The benefits of such coating on the tensile and buckling behavior of single-walled CNTs (SWCNTs) are illustrated through molecular dynamics (MD) simulations of the resulted nanostructures during the deformation. The AIREBO and Tersoff-Brenner potentials are employed to model the interatomic forces between the carbon and boron nitride atoms, respectively. The effects of chiral indices, aspect ratio, presence of mono-vacancy defects and coating dimension on coated/non-coated CNTs are examined. It is demonstrated that the coated defective CNTs exhibit remarkably enhanced ultimate strength, buckling load capacity and Young's modulus. The proposed coating not only enhances the mechanical properties of the resulted nanostructure, but also conceals it from few external factors impacting the behavior of the CNT such as humidity and high temperature.

  6. Lignin-Modified Carbon Nanotube/Graphene Hybrid Coating as Efficient Flame Retardant

    Directory of Open Access Journals (Sweden)

    Kunlin Song

    2017-11-01

    Full Text Available To reduce fire hazards and expand high-value applications of lignocellulosic materials, thin films comprising graphene nanoplatelets (GnPs and multi-wall carbon nanotubes (CNTs pre-adsorbed with alkali lignin were deposited by a Meyer rod process. Lightweight and highly flexible papers with increased gas impermeability were obtained by coating a protective layer of carbon nanomaterials in a randomly oriented and overlapped network structure. Assessment of the thermal and flammability properties of papers containing as low as 4 wt % carbon nanomaterials exhibited self-extinguishing behavior and yielded up to 83.5% and 87.7% reduction in weight loss and burning area, respectively, compared to the blank papers. The maximum burning temperature as measured by infrared pyrometry also decreased from 834 °C to 705 °C with the presence of flame retardants. Furthermore, papers coated with composites of GnPs and CNTs pre-adsorbed with lignin showed enhanced thermal stability and superior fire resistance than samples treated with either component alone. These outstanding flame-retardant properties can be attributed to the synergistic effects between GnPs, CNTs and lignin, enhancing physical barrier characteristics, formation of char and thermal management of the material. These results provide great opportunities for the development of efficient, cost-effective and environmentally sustainable flame retardants.

  7. Carbon nanotubes

    OpenAIRE

    SLOBODAN N. MARINKOVIC

    2008-01-01

    Nanotubes, the last in the focus of scientists in a series of “all carbon” materials discovered over the last several decades are the most interesting and have the greatest potential. This review aims at presenting in a concise manner the considerable amount of knowledge accumulated since the discovery of this amazing form of solid carbon, particularly during the last 15 years. The topics include methods of synthesis, mathematical description, characterization by Raman spectroscopy, most impo...

  8. Synthesis of ZnO coated multi-walled carbon nanotubes and their antibacterial activities.

    Science.gov (United States)

    Sui, Minghao; Zhang, Lingdian; Sheng, Li; Huang, Shuhang; She, Lei

    2013-05-01

    ZnO coated multi-walled carbon nanotubes (ZnO/MWCNTs) were prepared and evaluated for their application potentials as an antimicrobial material for simultaneous concentrating and inactivating pathogenic bacteria. X-ray energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), and X-ray photoelectron spectra (XPS) were used to characterize the ZnO/MWCNTs. Escherichia coli (E. coli) was employed as the target bacterium. Comparing with the raw and the purified MWCNTs (r-MWCNTs and p-MWCNTs), which have been reported to possess antibacterial activity towards E. coli, ZnO/MWCNTs exhibited stronger antibacterial ability. The deposited ZnO was suggested to play an important role in the bactericidal action of ZnO/MWCNTs, while, the r-MWCNTs and p-MWCNTs served as more like adsorbing materials for E. coli. Copyright © 2013 Elsevier B.V. All rights reserved.

  9. Capture of unstable protein complex on the streptavidin-coated single-walled carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Liu Zunfeng, E-mail: liuz2@chem.leidenuniv.nl; Voskamp, Patrick [Cell Observatory, Biophysical Structural Chemistry, Leiden Institute of Chemistry (Netherlands); Zhang Yue; Chu Fuqiang [Changzhou University, School of Pharmaceutical Engineering and Life Science (China); Abrahams, Jan Pieter, E-mail: abrahams@chem.leidenuniv.nl [Cell Observatory, Biophysical Structural Chemistry, Leiden Institute of Chemistry (Netherlands)

    2013-04-15

    Purification of unstable protein complexes is a bottleneck for investigation of their 3D structure and in protein-protein interaction studies. In this paper, we demonstrate that streptavidin-coated single-walled carbon nanotubes (Strep Bullet SWNT) can be used to capture the biotinylated DNA-EcoRI complexes on a 2D surface and in solution using atomic force microscopy and electrophoresis analysis, respectively. The restriction enzyme EcoRI forms unstable complexes with DNA in the absence of Mg{sup 2+}. Capturing the EcoRI-DNA complexes on the Strep Bullet SWNT succeeded in the absence of Mg{sup 2+}, demonstrating that the Strep Bullet SWNT can be used for purifying unstable protein complexes.

  10. High stability electron field emitters made of nanocrystalline diamond coated carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Sankaran, K. J.; Tai, N. H., E-mail: nhtai@mx.nthu.edu.tw [Department of Materials Science and Engineering, National Tsing-Hua University, Hsinchu 300, Taiwan (China); Srinivasu, K.; Leou, K. C. [Department of Engineering and System Science, National Tsing-Hua University, Hsinchu 300, Taiwan (China); Lin, I. N., E-mail: inanlin@mail.tku.edu.tw [Department of Physics, Tamkang University, Tamsui 251, Taiwan (China)

    2013-12-16

    We report enhanced life-time stability for the electron field emitters prepared by coating nanocrystalline diamond (NCD) on carbon nanotubes (CNTs). Upon overcoming the problem of poor stability in CNTs, the NCD-CNTs exhibit excellent life-time stability of 250 min tested at different applied voltages of 600 and 900 V. In contrast, the life-time stability of CNTs is only 33 min even at relatively low voltage of 360 V and starts arcing at 400 V. Hence, the NCD-CNTs with improved life-time stability have great potential for the applications as cathodes in flat panel displays and microplasma display devices.

  11. Effect of tetrahedral amorphous carbon coating on the resistivity and wear of single-walled carbon nanotube network

    Energy Technology Data Exchange (ETDEWEB)

    Iyer, Ajai, E-mail: ajai.iyer@aalto.fi; Etula, Jarkko; Liu, Xuwen; Koskinen, Jari [Department of Materials Science and Engineering, School of Chemical Technology, Aalto University, P.O. Box 16200, 00076 Espoo (Finland); Kaskela, Antti; Kauppinen, Esko I. [NanoMaterials Group, Department of Applied Physics, School of Science, Aalto University, P.O. Box 15100, 00076 Espoo (Finland); Novikov, Serguei [Department of Micro and Nanosciences, Aalto University, P.O. Box 13500, 00076 Aalto (Finland)

    2016-05-14

    Single walled carbon nanotube networks (SWCNTNs) were coated by tetrahedral amorphous carbon (ta-C) to improve the mechanical wear properties of the composite film. The ta-C deposition was performed by using pulsed filtered cathodic vacuum arc method resulting in the generation of C+ ions in the energy range of 40–60 eV which coalesce to form a ta-C film. The primary disadvantage of this process is a significant increase in the electrical resistance of the SWCNTN post coating. The increase in the SWCNTN resistance is attributed primarily to the intrinsic stress of the ta-C coating which affects the inter-bundle junction resistance between the SWCNTN bundles. E-beam evaporated carbon was deposited on the SWCNTNs prior to the ta-C deposition in order to protect the SWCNTN from the intrinsic stress of the ta-C film. The causes of changes in electrical resistance and the effect of evaporated carbon thickness on the changes in electrical resistance and mechanical wear properties have been studied.

  12. Sol-gel synthesis of tantalum oxide and phosphonic acid-modified carbon nanotubes composite coatings on titanium surfaces.

    Science.gov (United States)

    Maho, Anthony; Detriche, Simon; Delhalle, Joseph; Mekhalif, Zineb

    2013-07-01

    Carbon nanotubes used as fillers in composite materials are more and more appreciated for the outstanding range of accessible properties and functionalities they generate in numerous domains of nanotechnologies. In the framework of biological and medical sciences, and particularly for orthopedic applications and devices (prostheses, implants, surgical instruments, …), titanium substrates covered by tantalum oxide/carbon nanotube composite coatings have proved to constitute interesting and successful platforms for the conception of solid and biocompatible biomaterials inducing the osseous regeneration processes (hydroxyapatite growth, osteoblasts attachment). This paper describes an original strategy for the conception of resistant and homogeneous tantalum oxide/carbon nanotubes layers on titanium through the introduction of carbon nanotubes functionalized by phosphonic acid moieties (-P(=O)(OH)2). Strong covalent C-P bonds are specifically inserted on their external sidewalls with a ratio of two phosphonic groups per anchoring point. Experimental results highlight the stronger "tantalum capture agent" effect of phosphonic-modified nanotubes during the sol-gel formation process of the deposits compared to nanotubes bearing oxidized functions (-OH, -C=O, -C(=O)OH). Particular attention is also paid to the relative impact of the rate of functionalization and the dispersion degree of the carbon nanotubes in the coatings, as well as their wrapping level by the tantalum oxide matrix material. The resulting effect on the in vitro growth of hydroxyapatite is also evaluated to confirm the primary osseous bioactivity of those materials. Chemical, structural and morphological features of the different composite deposits described herein are assessed by X-ray photoelectron spectroscopy (XPS), scanning (SEM) and transmission (TEM) electronic microscopies, energy dispersive X-rays analysis (EDX) and peeling tests. Copyright © 2013 Elsevier B.V. All rights reserved.

  13. Size reduction of 3D-polymer-coated single-walled carbon nanotubes by ultracentrifugation

    Science.gov (United States)

    Tsutsumi, Yusuke; Fujigaya, Tsuyohiko; Nakashima, Naotoshi

    2015-11-01

    We describe a novel single-walled carbon nanotube (SWNT) cutting method without introducing any structural defects on the tubes; namely, the finding that simple ultracentrifugation at 600 000g for the SWNTs coated with a cross-linked polymer formed by poly(N-isopropylacrylamide) (PNIPAM) or the polyethylene glycol-carrying PNIPAM copolymer provides shortened (water and buffer solution due to the remaining cross-linked polymer structures on the SWNTs. The present method is very simple (only ultracentrifugation) and the yield is very high, which are the advantages in the preparation of many shortened isolated SWNTs with specific properties and functions that are applicable in many fields including bioapplications in vivo, such as imaging, NIR-hyperthermic treatment, photodynamic therapy, etc.We describe a novel single-walled carbon nanotube (SWNT) cutting method without introducing any structural defects on the tubes; namely, the finding that simple ultracentrifugation at 600 000g for the SWNTs coated with a cross-linked polymer formed by poly(N-isopropylacrylamide) (PNIPAM) or the polyethylene glycol-carrying PNIPAM copolymer provides shortened (water and buffer solution due to the remaining cross-linked polymer structures on the SWNTs. The present method is very simple (only ultracentrifugation) and the yield is very high, which are the advantages in the preparation of many shortened isolated SWNTs with specific properties and functions that are applicable in many fields including bioapplications in vivo, such as imaging, NIR-hyperthermic treatment, photodynamic therapy, etc. Electronic supplementary information (ESI) available: DLS profile of the supernatant after one ultracentrifugation at 600 000g for SWNT/PNIPAM (NIPAM : BIS = 100 : 1). DLS profiles, AFM images and length histograms, average length as a function of the number of repeated centrifugations, Raman spectra, absorption spectra and PL mappings of SWNT/PNIPAM (NIPAM : BIS = 18 : 1). See DOI: 10.1039/c5

  14. Facile Preparation of Octadecyl Monoliths with Incorporated Carbon Nanotubes and Neutral Monoliths with Coated Carbon Nanotubes Stationary Phases for HPLC of Small and Large Molecules by Hydrophobic and π-π Interactions

    Science.gov (United States)

    Mayadunne, Erandi; Rassi, Ziad El

    2014-01-01

    Two approaches for incorporating carbon nanotubes into monolithic columns for HPLC are described in this report. They pertain to the investigation of carbon nanotubes either (i) as entities to modulate solute retention on monolithic columns bearing well defined retentive ligands or (ii) as entities that constitute the stationary phase responsible for solute retention and separation. Approach (i) involved the incorporation of carbon nanotubes into octadecyl monolithic columns while approach (ii) concerns the preparation and evaluation of an ideal monolithic support and coating it with carbon nanotubes to yield a real “carbon nanotube stationary phase” for the HPLC separation of a wide range of solutes. First, an octadecyl monolithic column based on the in situ polymerization of octadecyl acrylate and trimethylolpropane trimethacrylate was optimized for use in HPLC separations of small and large solutes (e.g., proteins). To further modulate the retention and separation of proteins, small amounts of carbon nanotubes were incorporated into the octadecyl monolith column. In approach (ii), an inert, relatively polar monolith based on the in situ polymerization of glyceryl monomethacrylate (GMM) and ethylene glycol dimethacrylate (EDMA) proved to be the most suitable support for the preparation of “carbon nanotube stationary phase”. This carbon nanotube “coated” monolith proved useful in the HPLC separation of a wide range of small solutes including enantiomers. In approach (ii), a more homogeneous incorporation of carbon nanotubes into the diol monolithic columns (i.e., GMM/EDMA) was achieved when hydroxyl functionalized carbon nanotubes were incorporated into the GMM/EDMA monolithic support. In addition, high power sonication for a short time enhanced further the homogeneity of the monolith incorporated with nanotubes. In all cases, nonpolar and π interactions were responsible for solute retention on the monolith incorporated carbon nanotubes. PMID:25127634

  15. 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...

  16. Silica-coated multi-walled carbon nanotubes impregnated with polyethyleneimine for carbon dioxide capture under the flue gas condition

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Min-Sang; Park, Soo-Jin, E-mail: sjpark@inha.ac.kr

    2015-03-15

    In this study, silica-coated multi-walled carbon nanotubes impregnated with polyethyleneimine (PEI) were prepared via a two-step process: (i) hydrolysis of tetraethylorthosilicate onto multi-walled carbon nanotubes, and (ii) impregnation of PEI. The adsorption properties of CO{sub 2} were investigated using CO{sub 2} adsorption–desorption isotherms at 298 K and thermogravimetric analysis under the flue gas condition (15% CO{sub 2}/85% N{sub 2}). The results obtained in this study indicate that CO{sub 2} adsorption increases after impregnation of PEI. The increase in CO{sub 2} capture was attributed to the affinity between CO{sub 2} and the amine groups. CO{sub 2} adsorption–desorption experiments, which were repeated five times, also showed that the prepared adsorbents have excellent regeneration properties. - Graphical abstract: Fabrication and CO{sub 2} adsorption process of the S-MWCNTs impregnated with PEI. - Highlights: • Silica coated-MWCNT impregnated with PEI was synthesized. • Amine groups of PEI gave CO{sub 2} affinity sites on MWCNT surfaces. • The S-MWCNT/PEI(50) exhibited the highest CO{sub 2} adsorption capacity.

  17. Thermal Conductivity of Epoxy Resin Reinforced with Magnesium Oxide Coated Multiwalled Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Fei-Peng Du

    2013-01-01

    Full Text Available Magnesium oxide coated multiwalled carbon nanotubes (MgO@MWNT were fabricated and dispersed into epoxy matrix. The microstructures of MgO@MWNT and epoxy/MgO@MWNT nanocomposites were characterized by TEM and SEM. Electrical resistivity and thermal conductivity of epoxy nanocomposites were investigated with high resistance meter and thermal conductivity meter, respectively. MgO@MWNT has core-shell structure with MgO as shell and nanotube as core, and the thickness of MgO shell is ca. 15 nm. MgO@MWNT has been dispersed well in the epoxy matrix. MgO@MWNT loaded epoxy nanocomposites still retain electrical insulation inspite of the filler content increase. However, thermal conductivity of epoxy was increased with the MgO@MWNT content increasing. When MgO@MWNT content reached 2.0 wt.%, thermal conductivity was increased by 89% compared to neat epoxy, higher than that of unmodified MWNT nanocomposites with the same loading content.

  18. Comprehensive Environmental Assessment Applied to Multiwalled Carbon Nanotube Flame-Retardant Coatings in Upholstery Textiles: A Case Study Presenting Priority Research Gaps for Future Risk Assessments (Final Report)

    Science.gov (United States)

    In September 2013, EPA announced the availability of the final report, Comprehensive Environmental Assessment Applied to Multiwalled Carbon Nanotube Flame-Retardant Coatings in Upholstery Textiles: A Case Study Presenting Priority Research Gaps for Future Risk Assessments...

  19. Coating carbon nanotubes with a polystyrene-based polymer protects against pulmonary toxicity

    Directory of Open Access Journals (Sweden)

    Rossi Michel J

    2011-01-01

    Full Text Available Abstract Background carbon nanotubes (CNT can have adverse effects on health. Therefore, minimizing the risk associated with CNT exposure is of crucial importance. The aim of this work was to evaluate if coating multi-walled CNT (MWCNT with polymers could modify their toxicity, thus representing a useful strategy to decrease adverse health effects of CNT. We used industrially-produced MWCNT uncoated (NT1 or coated (50/50 wt% with acid-based (NT2 or polystyrene-based (NT3 polymer, and exposed murine macrophages (RAW 264.7 cell line or Balb/c mice by intratracheal administration. Biological experiments were performed both in vitro and in vivo, examining time- and dose-dependent effects of CNT, in terms of cytotoxicity, expression of genes and proteins related to oxidative stress, inflammation and tissue remodeling, cell and lung tissue morphology (optical and transmission electron microscopy, and bronchoalveolar lavage fluid content analysis. Results extensive physico-chemical characterization of MWCNT was performed, and showed, although similar dimensions for the 3 MWCNT, a much smaller specific surface area for NT2 and NT3 as compared to NT1 (54.1, 34 and 227.54 m2/g respectively, along with different surface characteristics. MWCNT-induced cytotoxicity, oxidative stress, and inflammation were increased by acid-based and decreased by polystyrene-based polymer coating both in vitro in murine macrophages and in vivo in lung of mice monitored for 6 months. Conclusions these results demonstrate that coating CNT with polymers, without affecting their intrinsic structure, may constitute a useful strategy for decreasing CNT toxicity, and may hold promise for improving occupational safety and that of general the user.

  20. Carbon nanotube composite materials

    Science.gov (United States)

    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.

  1. Large-area fluidic assembly of single-walled carbon nanotubes through dip-coating and directional evaporation

    Science.gov (United States)

    Kim, Pilnam; Kang, Tae June

    2017-12-01

    We present a simple and scalable fluidic-assembly approach, in which bundles of single-walled carbon nanotubes (SWCNTs) are selectively aligned and deposited by directionally controlled dip-coating and solvent evaporation processes. The patterned surface with alternating regions of hydrophobic polydimethyl siloxane (PDMS) (height 100 nm) strips and hydrophilic SiO2 substrate was withdrawn vertically at a constant speed ( 3 mm/min) from a solution bath containing SWCNTs ( 0.1 mg/ml), allowing for directional evaporation and subsequent selective deposition of nanotube bundles along the edges of horizontally aligned PDMS strips. In addition, the fluidic assembly was applied to fabricate a field effect transistor (FET) with highly oriented SWCNTs, which demonstrate significantly higher current density as well as high turn-off ratio (T/O ratio 100) as compared to that with randomly distributed carbon nanotube bundles (T/O ratio <10).

  2. Specifically Grafting Hematin on MPTS-Coated Carbon Nanotubes for Catalyzing the Oxidation of Aniline

    Directory of Open Access Journals (Sweden)

    Kunkun Zheng

    2016-08-01

    Full Text Available Catalysts supported on nanomaterials have been widely investigated for the treatment of hazardous materials. This work has developed a novel method for grafting hematin on nanomaterials for catalyzing the oxidation of aniline in order to remove aniline from wastewater. Magnetic multi-walled carbon nanotubes (M-MWCNTs were coated with a layer formed through the hydrolysis and condensation of 3-mercaptopropyltriethoxysilane (MPTS. Hematin was specifically grafted on the MPTS-coated M-MWCNTs through thiol-alkene reaction. Hematin-MPTS-M-MWCNTs were used to catalyze the oxidation of aniline, and a high efficiency has been obtained. Consecutive use of the conjugate of hematin-MPTS-M-MWCNTs has been investigated, and the activity has been retained to a significant extent after five reaction/cleaning cycles. The result demonstrates that hematin-MPTS-M-MWCNTs are efficient for catalyzing the oxidation of aniline. The methodology for the specific grafting of hematin is of general utility, it is an easy-to-operate method and can be extended to other supports. Potentially, hematin-MPTS-based conjugates have a widespread application in catalyzing the removal of aniline from wastewater.

  3. Carbon nanotube-coated macroporous sponge for microbial fuel cell electrodes

    KAUST Repository

    Xie, Xing

    2012-01-01

    The materials that are used to make electrodes and their internal structures significantly affect microbial fuel cell (MFC) performance. In this study, we describe a carbon nanotube (CNT)-sponge composite prepared by coating a sponge with CNTs. Compared to the CNT-coated textile electrodes evaluated in prior studies, CNT-sponge electrodes had lower internal resistance, greater stability, more tunable and uniform macroporous structure (pores up to 1 mm in diameter), and improved mechanical properties. The CNT-sponge composite also provided a three-dimensional scaffold that was favorable for microbial colonization and catalytic decoration. Using a batch-fed H-shaped MFC outfitted with CNT-sponge electrodes, an areal power density of 1.24 W m -2 was achieved when treating domestic wastewater. The maximum volumetric power density of a continuously fed plate-shaped MFC was 182 W m -3. To our knowledge, these are the highest values obtained to date for MFCs fed domestic wastewater: 2.5 times the previously reported maximum areal power density and 12 times the previously reported maximum volumetric power density. © 2011 The Royal Society of Chemistry.

  4. Highly sensitive strain gauges with carbon nanotubes: From bulk nanocomposites to multifunctional coatings for damage sensing

    Science.gov (United States)

    Sánchez-Romate, Xoan F.; Moriche, Rocío; Jiménez-Suárez, Alberto; Sánchez, María; Prolongo, Silvia G.; Güemes, Alfredo; Ureña, Alejandro

    2017-12-01

    Sensing capabilities of carbon nanotube (CNT) epoxy materials have been studied in order to develop multifunctional coatings for damage detection. For that purposes CNT doped epoxy nmixtures have been manufacturing using toroidal stirring. The microstructural characterization of CNT dispersion has been carried out by optical microscopy, showing the good homogenization effect induced by toroidal stirring. Then, electromechanical tests have been carried out on bulk nanocomposites and strain gauges. From tensile tests, it has been noticed that the Gauge Factor (GF) of strain gauges is much higher than those of bulk nanocomposites and conventional metallic gauges. Bending tests, which gauges made over tensile or compressive faces of the samples show that strain gauges have different behaviors while bulk materials show similar ones due to electrical volume interactions, proving the potential of strain gauges for monitoring complex load states. Damage sensing of CNT/epoxy materials has been also proved by inducing artificial defects on a monitored coating as changes in electrical resistance related to damage size. Thus damage detection, location and quantification have been achieved.

  5. Single Carbon Fibers with a Macroscopic-Thickness, 3D Highly Porous Carbon Nanotube Coating.

    Science.gov (United States)

    Zou, Mingchu; Zhao, Wenqi; Wu, Huaisheng; Zhang, Hui; Xu, Wenjing; Yang, Liusi; Wu, Shiting; Wang, Yunsong; Chen, Yijun; Xu, Lu; Cao, Anyuan

    2018-02-19

    Carbon fiber (CF) grafted with a layer of carbon nanotubes (CNTs) plays an important role in composite materials and other fields; to date, the applications of CNTs@CF multiscale fibers are severely hindered by the limited amount of CNTs grafted on individual CFs and the weak interfacial binding force. Here, monolithic CNTs@CF fibers consisting of a 3D highly porous CNT sponge layer with macroscopic-thickness (up to several millimeters), which is directly grown on a single CF, are fabricated. Mechanical tests reveal high sponge-CF interfacial strength owing to the presence of a thin transitional layer, which completely inhibits the CF slippage from the matrix upon fracture in CNTs@CF fiber-epoxy composites. The porous conductive CNTs@CF hybrid fibers also act as a template for introducing active materials (pseudopolymers and oxides), and a solid-state fiber-shaped supercapacitor and a fiber-type lithium-ion battery with high performances are demonstrated. These CNTs@CF fibers with macroscopic CNT layer thickness have many potential applications in areas such as hierarchically reinforced composites and flexible energy-storage textiles. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Label-free capture of breast cancer cells spiked in buffy coats using carbon nanotube antibody micro-arrays

    Science.gov (United States)

    Khosravi, Farhad; Trainor, Patrick; Rai, Shesh N.; Kloecker, Goetz; Wickstrom, Eric; Panchapakesan, Balaji

    2016-04-01

    We demonstrate the rapid and label-free capture of breast cancer cells spiked in buffy coats using nanotube-antibody micro-arrays. Single wall carbon nanotube arrays were manufactured using photo-lithography, metal deposition, and etching techniques. Anti-epithelial cell adhesion molecule (EpCAM) antibodies were functionalized to the surface of the nanotube devices using 1-pyrene-butanoic acid succinimidyl ester functionalization method. Following functionalization, plain buffy coat and MCF7 cell spiked buffy coats were adsorbed on to the nanotube device and electrical signatures were recorded for differences in interaction between samples. A statistical classifier for the ‘liquid biopsy’ was developed to create a predictive model based on dynamic time warping to classify device electrical signals that corresponded to plain (control) or spiked buffy coats (case). In training test, the device electrical signals originating from buffy versus spiked buffy samples were classified with ˜100% sensitivity, ˜91% specificity and ˜96% accuracy. In the blinded test, the signals were classified with ˜91% sensitivity, ˜82% specificity and ˜86% accuracy. A heatmap was generated to visually capture the relationship between electrical signatures and the sample condition. Confocal microscopic analysis of devices that were classified as spiked buffy coats based on their electrical signatures confirmed the presence of cancer cells, their attachment to the device and overexpression of EpCAM receptors. The cell numbers were counted to be ˜1-17 cells per 5 μl per device suggesting single cell sensitivity in spiked buffy coats that is scalable to higher volumes using the micro-arrays.

  7. Label-free capture of breast cancer cells spiked in buffy coats using carbon nanotube antibody micro-arrays.

    Science.gov (United States)

    Khosravi, Farhad; Trainor, Patrick; Rai, Shesh N; Kloecker, Goetz; Wickstrom, Eric; Panchapakesan, Balaji

    2016-04-01

    We demonstrate the rapid and label-free capture of breast cancer cells spiked in buffy coats using nanotube-antibody micro-arrays. Single wall carbon nanotube arrays were manufactured using photo-lithography, metal deposition, and etching techniques. Anti-epithelial cell adhesion molecule (EpCAM) antibodies were functionalized to the surface of the nanotube devices using 1-pyrene-butanoic acid succinimidyl ester functionalization method. Following functionalization, plain buffy coat and MCF7 cell spiked buffy coats were adsorbed on to the nanotube device and electrical signatures were recorded for differences in interaction between samples. A statistical classifier for the 'liquid biopsy' was developed to create a predictive model based on dynamic time warping to classify device electrical signals that corresponded to plain (control) or spiked buffy coats (case). In training test, the device electrical signals originating from buffy versus spiked buffy samples were classified with ∼100% sensitivity, ∼91% specificity and ∼96% accuracy. In the blinded test, the signals were classified with ∼91% sensitivity, ∼82% specificity and ∼86% accuracy. A heatmap was generated to visually capture the relationship between electrical signatures and the sample condition. Confocal microscopic analysis of devices that were classified as spiked buffy coats based on their electrical signatures confirmed the presence of cancer cells, their attachment to the device and overexpression of EpCAM receptors. The cell numbers were counted to be ∼1-17 cells per 5 μl per device suggesting single cell sensitivity in spiked buffy coats that is scalable to higher volumes using the micro-arrays.

  8. Influence of Carbon Nanotube Coatings on Carbon Fiber by Ultrasonically Assisted Electrophoretic Deposition on Its Composite Interfacial Property

    Directory of Open Access Journals (Sweden)

    Jianjun Jiang

    2016-08-01

    Full Text Available Carbon nanotube (CNT coatings were utilized to enhance the interfacial properties of carbon fiber (CF/epoxy(EP composites by ultrasonically assisted electrophoretic deposition (EPD. A characterization of the CF surface properties was done before and after coating (surface chemistry, surface morphologies, and surface energy. The result shows that oxygenated groups concentrations of the CF surfaces experienced significant increases from 12.11% to 24.78%. Moreover, the uniform and homogeneous CNT films were tightly attached on the surface of CF, and the surface wettability of CF is significant improved by enhanced surface free energy when introduced ultrasonic during the EPD process. In addition, the interlaminar shear strength (ILSS and water absorption of CF/EP composite were measured. Scanning electron microscopy (SEM revealed that the fracture mechanisms of the new interface layer formed by depositing CNTs on the CF surface contributed to the enhancement of the mechanical performance of the epoxy. This means that the efficient method to improve interfacial performance of composites has shown great commercial application potential.

  9. New catalyst supports prepared by surface modification of graphene- and carbon nanotube structures with nitrogen containing carbon coatings

    Science.gov (United States)

    Oh, Eun-Jin; Hempelmann, Rolf; Nica, Valentin; Radev, Ivan; Natter, Harald

    2017-02-01

    We present a new and facile method for preparation of nitrogen containing carbon coatings (NCC) on the surface of graphene- and carbon nanotubes (CNT), which has an increased electronic conductivity. The modified carbon system can be used as catalyst support for electrocatalytic applications, especially for polymer electrolyte membrane fuel cells (PEMFC). The surface modification is performed by impregnating carbon structures with a nitrogen containing ionic liquid (IL) with a defined C:N ratio, followed by a thermal treatment under ambient conditions. We investigate the influence of the main experimental parameters (IL amount, temperature, substrate morphology) on the formation of the NCC. Additionally, the structure and the chemical composition of the resulting products are analyzed by electron microscopic techniques (SEM, TEM), energy disperse X-ray analysis (EDX), X-ray photoelectron spectroscopy (XPS) and hot extraction analysis. The modified surface has a nitrogen content of 29 wt% which decreases strongly at temperatures above 600 °C. The new catalyst supports are used for the preparation of PEMFC anodes which are characterized by polarization measurements and electrochemical impedance spectroscopy (EIS). Compared to unmodified graphene and CNT samples the electronic conductivity of the modified systems is increased by a factor of 2 and shows improved mass transport properties.

  10. Extraction of ochratoxin A in red wine with dopamine-coated magnetic multi-walled carbon nanotubes.

    Science.gov (United States)

    Wan, Hong; Zhang, Bo; Bai, Xiao-Lin; Zhao, Yan; Xiao, Meng-Wei; Liao, Xun

    2017-10-01

    A new, rapid, green, and cost-effective magnetic solid-phase extraction of ochratoxin A from red wine samples was developed using polydopamine-coated magnetic multi-walled carbon nanotubes as the absorbent. The polydopamine-coated magnetic multi-walled carbon nanotubes were fabricated with magnetic multi-walled carbon nanotubes and dopamine by an in situ oxidative self-polymerization approach. Transmission electron microscopy, dynamic light scattering, X-ray photoelectron spectroscopy and vibrating sample magnetometry were used to characterize the absorbents. Ochratoxin A was quantified with high-performance liquid chromatography coupled with fluorescence detection, with excitation and emission wavelengths of 338 and 455 nm, respectively. The conditions affecting the magnetic solid-phase extraction procedure, such as pH, extraction solution, extraction time, absorbent amount, desorption solution and desorption time were investigated to obtain the optimal extraction conditions. Under the optimized conditions, the extraction recovery was 91.8-104.5% for ochratoxin A. A linear calibration curve was obtained in the range of 0.1-2.0 ng/mL. The limit of detection was 0.07 ng/mL, and the limit of quantitation was 0.21 ng/mL. The recoveries of ochratoxin A for spiked red wine sample ranged from 95.65 to 100.65% with relative standard deviation less than 8%. The polydopamine-coated magnetic multi-walled carbon nanotubes showed a high affinity toward ochratoxin A, allowing selective extraction and quantification of ochratoxin A from complex sample matrixes. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Preparation and properties of natural rubber reinforced with polydopamine-coating modified carbon nanotubes

    Directory of Open Access Journals (Sweden)

    Y-L. Lu

    2017-01-01

    Full Text Available Multi-walled carbon nanotubes (MWCNTs were functionalized by polydopamine (PDA-coating and mixed with natural rubber (NR via latex compounding. Compared with pristine MWCNTs, the surface of MWCNT-PDA was covered by an amorphous and nanometer-scale PDA layer which had a large amount of oxygenic and nitric functional groups. So the MWCNT-PDA showed a perfect dispersion in NR matrix. The tensile strength of NR/MWCNT-PDA (5 phr composites is 28.6 MPa, compared with the pure NR, which increased by 42%. For the electrical properties, when the content of MWCNTPDA or MWCNTs is 2 phr, the volume resistivity of NR/MWCNT-PDA composites falls to about 2.7·109 Ω·cm, compared with 3.3·1013 Ω·cm of NR/MWCNT composites. The thermal conductivity of NR composites increased only by 28.2% when 5 phr MWCNT-PDA was added. A model proposed by Nan was used to calculate the thermal conductivity of NR/MWCNT composites, and the calculated values were compared with the experimental values, the results showed that the interface thermal resistance is the main reason why MWCNTs could not significantly increase the thermal conductivity of natural rubber.

  12. The detection of formaldehyde using microelectromechanical acoustic resonator with multiwalled carbon nanotubes-polyethyleneimine composite coating

    Science.gov (United States)

    Wang, Jingjing; Zhan, Da; Wang, Ke; Hang, Weiwei

    2018-01-01

    A micro-scale gas sensor based on mass-sensitive film bulk acoustic resonator is demonstrated for the detection of trace formaldehyde at room temperature. The composites mixed with multiwalled carbon nanotubes and polyethyleneimine (MWNTs-PEI) were coated on the resonator surface as the sensitive layer to specifically absorb formaldehyde molecules using a facile spray process. The influence of spraying processes on the formaldehyde sensing properties were investigated. Different response behaviors were determined by both the chemical absorption between formaldehyde molecules and the amine functional groups on PEI and the increase of absorption surface came from the nanostructure. The combination of high frequency of the film bulk acoustic resonator (~4.3 GHz) and the specific absorbability of MWNTs-PEI composites provided a high sensitivity in the detections of trace formaldehyde. The obtained ultra-low limit of detection was as low as 60 ppb with linear response, quick response/recovery time, good reproducibility and selectivity. The proposed sensor shows potential as a portable and convenient gas-sensing system for monitoring the low-level concentration of indoor air pollution.

  13. Detection of organophosphorous pesticides in soil samples with multiwalled carbon nanotubes coating SPME fiber.

    Science.gov (United States)

    Feng, Xilan; Li, Ying; Jing, Ruijun; Jiang, Xiaoying; Tian, Mengkui

    2014-12-01

    A headspace solid phase microextraction (HS-SPME) technique using stainless steel fiber coated with 20 μm multi-walled carbon nanotubes (MWCNTs) and gas chromatography with thermionic specific detector (GC-TSD) was developed to determine organophosphorous pesticides (OPPs) in soil. Parameters affecting the extraction efficiency such as extraction time and temperature, ionic strength, the volume of water added to the soil, sample solution volume to headspace volume ratio, desorption time, and desorption temperature were investigated and optimized. Compared to commercial polydimethylsiloxane (PDMS, 7 μm) fiber, the PDMS fiber was better to be corrected as phorate, whereas the MWCNTs fiber gave slightly better results for methyl parathion, chlorpyrifos and parathion. The optimized SPME method was applied to analyze OPPs in spiked soil samples. The limits of detection (LODs, S/N = 3) for the four pesticides were <0.216 ng g(-1), and their calibration curves were all linear (r (2) ≥ 0.9908) in the range from 1 to 200 ng g(-1). The precision (RSD, n = 6) for peak areas was 6.5 %-8.8 %. The recovery of the OPPs spiked real soil samples at 50 and 150 ng g(-1) ranged from 89.7 % to 102.9 % and 94.3 % to 118.1 %, respectively.

  14. Greener corona discharge for enhanced wind generation with a simple dip-coated carbon nanotube decoration

    Science.gov (United States)

    Wu, Yishan; Li, Jun; Ye, Jianchun; Chen, Xiaohong; Li, Huili; Huang, Sumei; Zhao, Ran; Ou-Yang, Wei

    2017-10-01

    Corona discharge-induced wind (CDIW) has been widely utilized in production lines in the food and semiconductor industries and in indoor devices such as electrostatic precipitators. Some ozone is inevitably emitted, posing serious health risks to respiratory system and lung function of a human being. In this work, a greener corona discharge with enhanced wind generation for a needle-to-cylinder discharge structure is demonstrated using a simple dip-coating method to attach carbon nanotubes (CNTs) to the discharge electrode of a stainless steel needle. Compared with a conventional discharge electrode without CNT decoration, the velocity of the CDIW is greatly enhanced, the onset voltage is lowered, the energy conversion efficiency is greatly improved and the concentration of generated ozone is much reduced, making this easy method of CNT decoration a promising candidate for greener corona discharge systems. In addition, several impact factors for improved performance are discussed mathematically and phenomenologically, providing an insight into the corona discharge and wind generation.

  15. Propagation characteristics of shock waves from a plane carbon-nanotube-coated optoacoustic transducer in water

    Science.gov (United States)

    Fan, Xiaofeng; Baek, Yonggeun; Ha, Kanglyeol; Kim, Moojoon; Kim, Jungsoon; Kim, Duckjong; Kang, Hyun Wook; Oh, Junghwan

    2017-07-01

    An optoacoustic transducer made of light-absorbing and elastomeric materials can generate high-pressure wide-band ultrasound waves in water when it is illuminated by a pulse laser. To generate such waves with high efficiency, carbon nanotubes (CNTs) and poly(dimethylsiloxane) (PDMS) are widely used as the light-absorbing and elastomeric materials, respectively. It was previously reported that an optoacoustic concave transducer made of these materials can produce strong shock waves, namely, blast waves, within its focal zone. In this study, we have shown that these waves can also be generated by a plane optoacoustic transducer fabricated by coating CNTs-PDMS on a poly(methyl methacrylate) (PMMA) plate. Some propagation characteristics of the blast wave generated were measured and compared with the calculated results. It was found that the propagation speed and attenuation of the wave are different from those of usual sounds. From the comparison of the measured and the calculated acoustic fields, it is assumed that every point on the transducer surface produces almost the same blast wave.

  16. Synergistic Ultrathin Functional Polymer-Coated Carbon Nanotube Interlayer for High Performance Lithium-Sulfur Batteries.

    Science.gov (United States)

    Kim, Joo Hyun; Seo, Jihoon; Choi, Junghyun; Shin, Donghyeok; Carter, Marcus; Jeon, Yeryung; Wang, Chengwei; Hu, Liangbing; Paik, Ungyu

    2016-08-10

    Lithium-sulfur (Li-S) batteries have been intensively investigated as a next-generation rechargeable battery due to their high energy density of 2600 W·h kg(-1) and low cost. However, the systemic issues of Li-S batteries, such as the polysulfide shuttling effect and low Coulombic efficiency, hinder the practical use in commercial rechargeable batteries. The introduction of a conductive interlayer between the sulfur cathode and separator is a promising approach that has shown the dramatic improvements in Li-S batteries. The previous interlayer work mainly focused on the physical confinement of polysulfides within the cathode part, without considering the further entrapment of the dissolved polysulfides. Here, we designed an ultrathin poly(acrylic acid) coated single-walled carbon nanotube (PAA-SWNT) film as a synergic functional interlayer to address the issues mentioned above. The designed interlayer not only lowers the charge transfer resistance by the support of the upper current collector but also localizes the dissolved polysulfides within the cathode part by the aid of a physical blocking and chemical bonding. With the synergic combination of PAA and SWNT, the sulfur cathode with a PAA-SWNT interlayer maintained higher capacity retention over 200 cycles and achieved better rate retention than the sulfur cathode with a SWNT interlayer. The proposed approach of combining a functional polymer and conductive support material can provide an optimiztic strategy to overcome the fundamental challenges underlying in Li-S batteries.

  17. Super-hydrophobic multi-walled carbon nanotube coatings for stainless steel

    Science.gov (United States)

    De Nicola, Francesco; Castrucci, Paola; Scarselli, Manuela; Nanni, Francesca; Cacciotti, Ilaria; De Crescenzi, Maurizio

    2015-04-01

    We have taken advantage of the native surface roughness and the iron content of AISI 316 stainless steel to directly grow multi-walled carbon nanotube (MWCNT) random networks by chemical vapor deposition (CVD) at low-temperature (\\lt 1000{}^\\circ C) without the addition of any external catalysts or time-consuming pre-treatments. In this way, super-hydrophobic MWCNT films on stainless steel sheets were obtained, exhibiting high contact angle values (154{}^\\circ ) and high adhesion force (high contact angle hysteresis). Furthermore, the investigation of MWCNT films with scanning electron microscopy (SEM) reveals a two-fold hierarchical morphology of the MWCNT random networks made of hydrophilic carbonaceous nanostructures on the tip of hydrophobic MWCNTs. Owing to the Salvinia effect, the hydrophobic and hydrophilic composite surface of the MWCNT films supplies a stationary super-hydrophobic coating for conductive stainless steel. This biomimetical inspired surface not only may prevent corrosion and fouling, but also could provide low friction and drag reduction.

  18. Enzyme precipitate coating of pyranose oxidase on carbon nanotubes and their electrochemical applications.

    Science.gov (United States)

    Kim, Jae Hyun; Hong, Sung-Gil; Wee, Youngho; Hu, Shuozhen; Kwon, Yongchai; Ha, Su; Kim, Jungbae

    2017-01-15

    Pyranose oxidase (POx), which doesn't have electrically non-conductive glycosylation moiety, was immobilized on carbon nanotubes (CNTs) via three different preparation methods: covalent attachment (CA), enzyme coating (EC) and enzyme precipitate coating (EPC). CA, EC and EPC of POx on CNTs were used to fabricate enzymatic electrodes for enzyme-based biosensors and biofuel cells. Improved enzyme loading of EPC resulted in 6.5 and 4.5 times higher activity per weight of CNTs than those of CA and EC, respectively. After 34 days at room temperature, EPC retained 65% of initial activity, while CA and EC maintained 9.2% and 26% of their initial activities, respectively. These results indicate that precipitation and crosslinking steps of EPC have an important role in maintaining enzyme activity. To demonstrate the feasibility of POx-based biosensors and biofuel cells, the enzyme electrodes were prepared using CA, EC, and EPC samples. In the case of biosensor, the sensitivities of the CA, EC, and EPC electrodes without BQ were measured to be 0.27, 0.76 and 3.7mA/M/cm(2), while CA, EC and EPC electrode with BQ showed 25, 25, and 60mA/M/cm(2) of sensitivities, respectively. The maximum power densities of biofuel cells using CA, EC and EPC electrodes without BQ were 41, 47 and 53µW/cm(2), while CA, EC and EPC electrodes with BQ showed 260, 330 and 500µW/cm(2), respectively. The POx immobilization and stabilization via the EPC approach can lead us to develop continuous glucose monitoring biosensors and high performing biofuel cells. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Plastic membrane, carbon paste and multiwalled carbon nanotube composite coated copper wire sensors for determination of oxeladin citrate using batch and flow injection techniques

    OpenAIRE

    Zayed,Sayed I. M.; Yousry M Issa

    2013-01-01

    The fabrication and performance characteristics of three novel potentiometric sensors for the determination of oxeladin citrate are described. The proposed sensors include a PVC plastic membrane sensor, a carbon paste sensor and a multiwalled carbon nanotube (MWCNT) composite coated copper wire sensor. The sensors are based on the oxeladin-phosphotungstate ion associate as electroactive material and dibutyl phthalate as solvent mediator. The developed sensors exhibited near nernstian slopes o...

  20. TiO{sub 2} coated multi-wall carbon nanotube as a corrosion inhibitor for improving the corrosion resistance of BTESPT coatings

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yuping; Zhu, Hongzheng; Zhuang, Chen [Institute of Materials Science and Engineering, Ocean University of China, Songling Road 238, Qingdao, 266100 (China); Chen, Shougang, E-mail: sgchen@ouc.edu.cn [Institute of Materials Science and Engineering, Ocean University of China, Songling Road 238, Qingdao, 266100 (China); Wang, Longqiang [Institute of Materials Science and Engineering, Ocean University of China, Songling Road 238, Qingdao, 266100 (China); Dong, Lihua [Institute of Ocean Materials and Engineering, Shanghai Maritime University, Shanghai, 200135 (China); Yin, Yansheng, E-mail: ysyin@shmtu.edu.cn [Institute of Ocean Materials and Engineering, Shanghai Maritime University, Shanghai, 200135 (China)

    2016-08-15

    The composite coatings of TiO{sub 2} coated multi-wall carbon nanotube (MWCNTs)/bis-[triethoxysilylpropyl]tetrasulfide (BTESPT) with different components were prepared on AA 2024 by the cathodic electrophoretic deposition technique and the experimental conditions were optimized to attain the appropriate volume ratio. The modified MWCNTs obviously improved the corrosion resistance of BTESPT and BTESPT/TiO{sub 2} coatings, especially for the long-term corrosion resistance ability because of the good dispersion of MWCNTs. The geometry of composite coatings were explored by scanning electron microscopy, fourier transform infrared spectra and the surface coverage rate (θ), the results indicate that the composite coatings produce good cross-linked structure at the interfacial layer, the coating compactness increases gradually with the addition of TiO{sub 2} and/or MWCNTs, and the composite coating effectively postpones the production of cracks with the addition of MWCNTs. - Highlights: • The composite coatings with different components were prepared on AA 2024 by the cathodic electrophoretic deposition technology. • The formation of composite coating on AA 2024 surface considerably improved the corrosion resistance ability. • The composite coating with a TiO{sub 2} to MWCNTs volume ratio of 4/1 shows the best corrosion resistance. • The kinetic evaluation of inhibitive behavior for different coatings against immersion time was explored.

  1. Biomedical applications of carbon-nanotube composites.

    Science.gov (United States)

    Meredith, Jay Russell; Jin, Chunming; Narayan, Roger J; Aggarwal, Ravi

    2013-01-01

    The unique physical, chemical and mechanical properties of carbon nanotubes make them attractive for a variety of biomedical applications. Carbon nanotubes have been used to modify conventional biomedical materials to enhance mechanical properties, biocompatibility, or to impart other functionalities. New multifunctional composite materials using carbon nanotubes have been developed by combining them with inorganic, polymeric or biological materials. The biomedical applications for which novel carbon nanotube composites have been investigated include antimicrobial coatings, neural implants, tissue engineering scaffolds and electrochemical biosensors. In this paper, research on development and application of carbon nanotube composites for biomedical applications has been reviewed.

  2. 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.

  3. Carbon Nanotubes and Modern Nanoagriculture

    KAUST Repository

    Serag, Maged F.

    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

  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

  5. Stable Wettability Control of Nanoporous Microstructures by iCVD Coating of Carbon Nanotubes.

    Science.gov (United States)

    Sojoudi, Hossein; Kim, Sanha; Zhao, Hangbo; Annavarapu, Rama Kishore; Mariappan, Dhanushkodi; Hart, A John; McKinley, Gareth H; Gleason, Karen K

    2017-11-13

    Scalable manufacturing of structured materials with engineered nanoporosity is critical for applications in energy storage devices (i.e. batteries and supercapacitors) and wettability control of surfaces (i.e. superhydrophobic and superomniphobic surfaces). Patterns formed in arrays of vertically aligned carbon nanotubes (VA-CNTs) have been extensively studied for these applications. However, the as-deposited features are often undesirably altered upon liquid infiltration and evaporation due to capillarity-driven aggregation of the low density CNTs. Here, it is found that an ultrathin, conformal, and low surface energy layer of poly-perfluorodecylacrylate, poly-(1H, 1H, 2H, 2H-perfluorodecylacrylate) (pPFDA) makes the VA-CNTs robust against surface-tension driven aggregation and densification. This single vapor-deposition step allows the fidelity of the as-deposited VA-CNT patterns to be retained during wet processing such as inking and subsequent drying. It is demonstrated how to establish omniphobicity or liquid infiltration by controlling the surface morphology. Retaining a crust of entangled CNTs and pPFDA clusters on top of the patterned VA-CNTs, produces micropillars with re-entrant features that prevent the infiltration of low surface tension liquids and thus gives rise to stable omniphobicity. Plasma treatments before and after polymer deposition removes the crust of the entangled CNTs and the pPFDA clusters, enabling liquid infiltration yet preventing densification of the highly-porous CNTs. The latter observation indicates the protective character of the pPFDA coating with potential application of these surfaces for direct contact printing of microelectronic features.

  6. Electrochemical detection of uric acid using ruthenium-dioxide-coated carbon nanotube directly grown onto Si wafer

    Science.gov (United States)

    Shih, Yi-Ting; Lee, Kuei-Yi; Lin, Chung-Kuang

    2015-12-01

    Carbon nanotubes (CNTs) directly grown onto a Si substrate by thermal chemical vapor deposition were used in uric acid (UA) detection. The process is simple and formation is easy without the need for additional chemical treatments. However, CNTs lack selectivity and sensitivity to UA. To enhance the electrochemical analysis, ruthenium oxide was used as a catalytic mediator in the modification of electrodes. The electrochemical results show that RuO2 nanostructures coated onto CNTs can strengthen the UA signal. The peak currents of RuO2 nanostructures coated onto CNTs linearly increase with increasing UA concentration, meaning that they can work as electrodes for UA detection. The lowest detection limit and highest sensitivity were 55 nM and 4.36 µA/µM, respectively. Moreover, the characteristics of RuO2 nanostructures coated onto CNTs were examined by scanning electron microscopy, transmission electron microscopy, and Raman spectroscopy.

  7. Separation of total lipids on human lipoproteins using surfactant-coated multiwalled carbon nanotubes as pseudostationary phase in capillary electrophoresis.

    Science.gov (United States)

    Su, Mei-Yu; Chen, Yen-Yi; Yang, Jian-Ying; Lin, You-Sian; Lin, Yang-Wei; Liu, Mine-Yine

    2014-04-01

    Surfactant-coated multiwalled carbon nanotubes (MWNTs) were used as pseudostationary phase (PSP) in CE to investigate the total lipids of high-density lipoproteins and low-density lipoproteins. To optimize the CE conditions, several experimental factors including carbon nanotube concentration, bile salt concentration, sodium phosphate (PB) concentration, organic modifier concentration and buffer pH value have been examined. In addition, the CE capillary temperature and applied voltage have also been examined. The optimal separation buffer selected was a mixture of 3.2 mg/L MWNT, 50 mM bile salt, 10 mM PB, 20% 1-propanol, pH 9.5. The optimal capillary temperature and applied voltage selected were 50°C and 20 kV, respectively. Phosphatidyl choline (PC) has been used as a model analyte and investigated by the optimal CE method. The linear range for PC was 0.1-3 mg/mL with a correlation coefficient of 0.9934, and the concentration LOD was 0.055 mg/mL. The optimal CE method has been used to characterize the total lipids of high-density lipoprotein and low-density lipoprotein. At absorbance 200 nm, one major peak and two or three minor peaks showed for the total lipids of lipoproteins within 13 minutes. Resolutions of the total lipids were enhanced using surfactant-coated MWNTs as PSPs in the CE separation buffer. However, resolutions of the total lipids were not enhanced using surfactant-coated single-walled carbon nanotubes as PSPs in the CE separation buffer. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Visibility and oxidation stability of hybrid-type copper mesh electrodes with combined nickel-carbon nanotube coating

    Science.gov (United States)

    Kim, Bu-Jong; Hwang, Young-Jin; Park, Jin-Seok

    2017-04-01

    Hybrid-type transparent conductive electrodes (TCEs) were fabricated by coating copper (Cu) meshes with carbon nanotube (CNT) via electrophoretic deposition, and with nickel (Ni) via electroplating. For the fabricated electrodes, the effects of the coating with CNT and Ni on their transmittance and reflectance in the visible-light range, electrical sheet resistance, and chromatic parameters (e.g., redness and yellowness) were characterized. Also, an oxidation stability test was performed by exposing the electrodes to air for 20 d at 85 °C and 85% temperature and humidity conditions, respectively. It was discovered that the CNT coating considerably reduced the reflectance of the Cu meshes, and that the Ni coating effectively protected the Cu meshes against oxidation. Furthermore, after the coating with CNT, both the redness and yellowness of the Cu mesh regardless of the Ni coating approached almost zero, indicating a natural color. The experiment results confirmed that the hybrid-type Cu meshes with combined Ni-CNT coating improved characteristics in terms of reflectance, sheet resistance, oxidation stability, and color, superior to those of the primitive Cu mesh, and also simultaneously satisfied most of the requirements for TCEs.

  9. Multifunctional, biocompatible and pH-responsive carbon nanotube- and graphene oxide/tectomer hybrid composites and coatings.

    Science.gov (United States)

    Garriga, Rosa; Jurewicz, Izabela; Seyedin, Shayan; Bardi, Niki; Totti, Stella; Matta-Domjan, Brigitta; Velliou, Eirini G; Alkhorayef, Mohammed A; Cebolla, Vicente L; Razal, Joselito M; Dalton, Alan B; Muñoz, Edgar

    2017-06-14

    Here we present a route for non-covalent functionalization of carboxylated multi-walled carbon nanotubes and graphene oxide with novel two-dimensional peptide assemblies. We show that self-assembled amino-terminated biantennary and tetraantennary oligoglycine peptides (referred to as tectomers) effectively coat carboxylated multi-walled carbon nanotubes and also strongly interact with graphene oxide due to electrostatic interactions and hydrogen bonding as the driving force, respectively. The resulting hybrids can be made into free-standing conducting composites or applied in the form of thin, pH-switchable bioadhesive coatings onto graphene oxide fibers. Monitoring of cell viability of pancreatic cell lines, seeded on those CNT hybrids, show that they can be used as two- and three-dimensional scaffolds to tissue engineer tumour models for studying ex vivo the tumour development and response to treatment. This highly versatile method in producing pH-responsive hybrids and coatings offers an attractive platform for a variety of biomedical applications and for the development of functional materials such as smart textiles, sensors and bioelectronic devices.

  10. Evaluation of Carbon Nanotubes Functionalized Polydimethylsiloxane Based Coatings for In-Tube Solid Phase Microextraction Coupled to Capillary Liquid Chromatography

    Directory of Open Access Journals (Sweden)

    Neus Jornet-Martínez

    2015-08-01

    Full Text Available In the present work, the performance of carbon nanotubes (c-CNTs functionalized polydimethylsiloxane (PDMS based coatings as extractive phases for in-tube solid phase microextraction (IT-SPME coupled to Capillary LC (CapLC has been evaluated. Carboxylic-single walled carbon nanotubes (c-SWNTs and carboxylic-multi walled carbon nanotubes (c-MWNTs have been immobilized on the activated surface of PDMS capillary columns. The effect of different percentages of diphenyl groups in the PDMS extractive phase has also been evaluated. The extraction capability of the capillary columns has been tested for different organic pollutants, nitrogen heterocyclic compounds and polycyclic aromatic compounds (PAHs. The results indicated that the use of the c-CNTs-PDMS capillary columns improve pyriproxyfen and mainly PAH extraction. Triazines were better extracted by unmodified TRB-35 and modified c-CNTs-PDMSTRB-5. The results showed that the extraction capability of the c-CNT capillary columns depends not only on the polarity of the analytes (as it occurs with PDMS columns but also on the interactions that the analytes can establish with the immobilized c-CNTs on the PDMS columns. The extraction efficiency has been evaluated on the basis of the preconcentration rate that can be achieved, and, in this sense, the best c-CNTs-PDMS capillary column for each group of compounds can be proposed.

  11. Deposition of nanocrystalline nonstoichiometric chromium oxide coatings on the surface of multiwalled carbon nanotubes by chromium acetylacetonate vapor pyrolysis

    Science.gov (United States)

    Kremlev, K. V.; Ob'edkov, A. M.; Ketkov, S. Yu.; Kaverin, B. S.; Semenov, N. M.; Gusev, S. A.; Andreev, P. V.

    2017-04-01

    Nanocrystalline coatings of nonstoichiometric chromium oxide have been obtained for the first time on the surface of multiwalled carbon nanotubes (MWCNTs) by the method of metalorganic chemical-vapor deposition using chromium acetylacetonate as a precursor. The new hybrid nanomaterial (Cr2O2.4/MWCNT) has been characterized by X-ray diffraction, scanning electron microscopy, and thermogravimetric analysis. It is established that oxidation of the hybrid nanomaterial in air under soft conditions (at 380°C) leads to the formation of nanocrystalline chromium oxide (Cr2O3) on the surface of MWCNTs.

  12. Amperometric detection of carbohydrates and thiols by using a glassy carbon electrode coated with Co oxide/multi-wall carbon nanotubes catalytic system.

    Science.gov (United States)

    Buratti, Susanna; Brunetti, Barbara; Mannino, Saverio

    2008-07-15

    A glassy carbon electrode coated with cobalt oxide/multi-wall carbon nanotubes (MWCNT) system was used for the detection of carbohydrates and thiols. The modification of the glassy carbon electrode increased the anodic current response of these organic compounds and decreased their overvoltage. The amperometric responses were extremely stable with no loss of sensitivity over many days of storage. Such attractive performance characteristics indicate great promise for using this new catalytic system for monitoring in fast and simple way compounds of great interest for food industry, biotechnology and clinical diagnostics.

  13. Synthesis and properties of carbon nanotubes coated tin dioxide for gas sensing applications

    OpenAIRE

    2012-01-01

    M.Tech. Among the materials being used for gas sensors, metal oxides are the most important materials because of their potential to detect many gases at low concentrations. Nevertheless, sensors made of metal oxide need to be operated at high temperatures (above 200°C) and have a weak sel ectivity. In order to overcome this difficulty, the materials are being investigated for gas sensing applications. Carbon nanotubes (CNTs) are promising materials with unique properties, such as high elec...

  14. Laser-driven coating of vertically aligned carbon nanotubes with manganese oxide from metal organic precursors for energy storage

    Science.gov (United States)

    Pérez del Pino, A.; György, E.; Alshaikh, I.; Pantoja-Suárez, F.; Andújar, J. L.; Pascual, E.; Amade, R.; Bertran-Serra, E.

    2017-09-01

    Carbon nanotubes-transition metal oxide systems are intensively studied due to their excellent properties for electrochemical applications. In this work, an innovative procedure is developed for the synthesis of vertically aligned multi-walled carbon nanotubes (VACNTs) coated with transition metal oxide nanostructures. VACNTs are grown by plasma enhanced chemical vapor deposition and coated with a manganese-based metal organic precursor (MOP) film based on manganese acetate solution. Subsequent UV pulsed laser irradiation induces the effective heating-decomposition of the MOP leading to the crystallization of manganese oxide nanostructures on the VACNT surface. The study of the morphology, structure and composition of the synthesized materials shows the formation of randomly oriented MnO2 crystals, with few nanometers in size, and to their alignment in hundreds of nm long filament-like structures, parallel to the CNT’s long axis. Electrochemical measurements reveal a significant increase of the specific capacitance of the MnO2-VACNT system (100 F g-1) as compared to the initial VACNT one (21 F g-1).

  15. Study on the effect of carbon nanotube coating on the refractive index sensing sensitivity of fiber modal interferometer

    Science.gov (United States)

    Zhang, Ya-nan; Xie, Wen-ge; Wang, Jianzhang; Wang, Pengzhao

    2018-01-01

    Refractive index sensing of liquid is important in the domain of chemistry and biology. Fiber optical sensors provide an excellent way to measure the refractive index due to their feasible integration to other fiber optics components, high sensitivity, small size, and distributed sensing. However, conventional optical sensors have different shortages. To find a practical way to measure the refractive index of liquid, this paper intended to combine Carbon Nanotube (CNT) with non-core fiber (NCF) to prepare a kind of modal interferometer sensor and to explore the effect of CNT coating on refractive index sensing properties of the modal interferometer. Firstly, a structure of single mode non-core single mode (SNS) fiber with a CNT film coating was proposed and simulated. The simulation results showed that the CNT coating could improve the refractive index sensitivity of the interferometer sensor. Then in the experiment part, the CNT solution was fabricated and deposited onto the NCF, and a refractive index sensing system was built to examine the property of the CNT-coated SNS interferometer sensor. During the experiment, the influence factors of sensitivity were summarized by testing the sensing performance under different conditions, and it was demonstrated that the CNT coating could improve the contrast of the interference spectrum, and also had the possibility to increase the refractive index sensitivity of the interferometer sensor.

  16. Carbon coated titanium dioxide nanotubes: synthesis, characterization and potential application as sorbents in dispersive micro solid phase extraction.

    Science.gov (United States)

    García-Valverde, M T; Lucena, R; Galán-Cano, F; Cárdenas, S; Valcárcel, M

    2014-05-23

    In this article, carbon coated titanium dioxide nanotubes (c-TNTs) have been synthesized. The synthesis of the bare TNTs (b-TNTs) using anatase as precursor and their coating with a caramel layer have been performed by simple and cheap hydrothermal processes. The final conversion of the caramel layer in a carbon coating has been accomplished by a thermal treatment (600°C) in an inert (Ar) atmosphere. The c-TNTs have been characterized by different techniques including transmission microscopy, infrared spectroscopy, X-ray powder diffraction, thermogravimetry and Brunauer, Emmett and Teller (BET) adsorption isotherms. The extraction performance of the c-TNTs under a microextraction format has been evaluated and compared with that provided by b-TNTs and multiwalled carbon nanotubes (MWCNTs) using naproxen and ketoprofen as model analytes. c-TNTs provided better results than the other nanoparticles, especially at low acidic pH values. In addition, c-TNTs presented a better dispersibility than MWCNTs, which is very interesting for their use in dispersive micro-solid phase extraction. Finally, a microextraction format, adapted to low sample volumes, has been proposed and applied for the determination of naproxen and ketoprofen in saliva and urine samples by liquid chromatography with UV detection. The results indicate that this approach is promising for the analysis of biological samples. In fact, the recoveries were in the range between 96% and 119% while the precision, expressed as relative standard deviation, was better than 8.5% and 26.3% for urine and saliva, respectively. The detection limits were in the range 34.1-40.8μg/L for saliva samples and 81.1-110μg/L for urine samples. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Multi-walled carbon nanotubes/graphene oxide hybrid and nanohydroxyapatite composite: A novel coating to prevent dentin erosion.

    Science.gov (United States)

    Nahorny, Sídnei; Zanin, Hudson; Christino, Vinie Abreu; Marciano, Fernanda Roberta; Lobo, Anderson Oliveira; Soares, Luís Eduardo Silva

    2017-10-01

    To date is emergent the development of novel coatings to protect erosion, especially to preventive dentistry and restorative dentistry. Here, for the first time we report the effectiveness of multi-walled carbon nanotube/graphene oxide hybrid carbon-base material (MWCNTO-GO) combined with nanohydroxyapatite (nHAp) as a protective coating for dentin erosion. Fourier transform Raman spectroscopy (FT-Raman), scanning electron (SEM), and transmission electron (TEM) microscopy were used to investigated the coatings and the effect of acidulated phosphate fluoride gel (APF) treatment on bovine teeth root dentin before and after erosion. The electrochemical corrosion performance of the coating was evaluated. Raman spectra identified that: (i) the phosphate (ν 1 PO 4 3- ) content of dentin was not significantly affected by the treatments and (ii) the carbonate (ν 1 CO 3 2- ) content in dentin increased when nHAp was used. However, the nHAp/MWCNTO-GO composite exposited lower levels of organic matrix (CH bonds) after erosion compared to other treatments. Interesting, SEM micrographs identified that the nHAp/MWCNTO-GO formed layers after erosive cycling when associate with APF treatment, indicating a possible chemical bond among them. Treatments of root dentin with nHAp, MWCNTO-GO, APF_MWCNTO-GO, and APF_nHAp/MWCNTO-GO increased the carbonate content, carbonate/phosphate ratio, and organic matrix band area after erosion. The potentiodynamic polarization curves and Nyquist plot showed that nHAp, MWCNT-GO and nHAp/MWCNT-GO composites acted as protective agents against corrosion process. Clearly, the nHAp/MWCNTO-GO composite was stable after erosive cycling and a thin and acid-resistant film was formed when associated to APF treatment. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Immobilization of ruthenium phthalocyanine on silica-coated multi-wall partially oriented carbon nanotubes: Electrochemical detection of fenitrothion pesticide

    Energy Technology Data Exchange (ETDEWEB)

    Canevari, Thiago C., E-mail: tccanevari@gmail.com [Engineering School, Mackenzie Presbyterian University, 01302-907 São Paulo, SP (Brazil); Prado, Thiago M.; Cincotto, Fernando H.; Machado, Sergio A.S. [Institute of Chemistry, State University of São Paulo, P.O. Box 780, 13560-970 São Carlos, SP (Brazil)

    2016-04-15

    Highlights: • Hybrid material, SiO{sub 2}/MWCNTs containing ruthenium phthalocyanine (RuPc) synthesized in situ. • Silica containing multi-walled carbon nanotube partially oriented. • Determination of pesticide fenitrothion in orange juice. - Abstract: This paper reports on the determination of the pesticide fenitrothion using a glassy carbon electrode modified with silica-coated, multi-walled, partially oriented carbon nanotubes, SiO{sub 2}/MWCNTs, containing ruthenium phthalocyanine (RuPc) synthesized in situ. The hybrid SiO{sub 2}/MWCNTs/RuPc material was characterized by UV–vis absorption spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM) and differential pulse voltammetry. The modified electrode showed well-defined peaks in the presence of fenitrothion in acetate buffer, pH 4.5, with a sensitivity of 0.0822 μA μM{sup −1} mm{sup −2} and a detection limit of 0.45 ppm. Notably, the modified SiO{sub 2}/MWCNTs/RuPc electrodes with did not suffer from significant influences in the presence of other organophosphorus pesticides during the determination of the fenitrothion pesticide. Moreover, this modified electrode showed excellent performance in the determination of fenitrothion in orange juice.

  19. Interaction between polymer-coated carbon nanotubes with coarse-grained computations

    Science.gov (United States)

    Vo, Minh D.; Papavassiliou, Dimitrios V.

    2017-10-01

    Dissipative particle dynamics computations were used to study the interaction between two carbon nanotubes (CNTs) stabilized with a polymer in an aqueous solution. The calculated interaction forces quantitatively described the steric effects of the adsorbed polymer on CNT agglomeration. It was found that the repulsive peak depended on the orientation of the CNTs relative to each other. A general equation describing the forces between polymer-stabilized CNTs was established, and its parameters were evaluated based on the results of the simulations. The procedure can be extended to other adsorbed molecules, like surfactants or biomolecules.

  20. Nanomaterial Case Study: A Comparison of Multiwalled Carbon Nanotube and Decabromodiphenyl Ether Flame-Retardant Coatings Applied to Upholstery Textiles (Independent Peer Review Draft)

    Science.gov (United States)

    This Independent Peer Review Draft document presents a case study of multiwalled carbon nanotubes (MWCNTs); it focuses on the specific example of MWCNTs as used in flame-retardant coatings applied to upholstery textiles. This case study is organized around the comprehensive envir...

  1. Carbon nanotubes with silver nanoparticle decoration and conductive polymer coating for improving the electrical conductivity of polycarbonate composites

    KAUST Repository

    Patole, Archana S.

    2015-01-01

    We proposed a strategy to enhance the conductivity of polycarbonate by using three-phase hybrid metallic/non-metallic fillers. Ethylene diamine (EDA) functionalized multiwalled carbon nanotubes (MWCNT-EDA) are first decorated with silver nanoparticles. These Ag/ MWCNT-EDA fillers are then coated with a conductive layer of ethylene glycol treated PEDOT: PSS (poly [3,4-ethylenedioxythiophene]: poly [styrenesulfonate]) (EP). In such an approach, the MWCNT backbone is covered by a highly conductive coating made of Ag nanoparticles surrounded by EP. To understand how Ag and EP form a highly conductive coating, the effect of different wt% of Ag nanoparticles on EP was studied. Ag nanoparticles around the size of 128 ± 28 nmeffectively lowered the volume resistivity of bulk EP, resulting in a highly conducting Ag/EP blend. We found that in the final Ag/MWCNT-EDA/EP assembly, the EP coating enhances the electrical conductivity in two ways: (1) it is an efficient dispersing agent that helps in achieving a uniform dispersion of the Ag/MWCNT-EDA and (2) it acts as a conductive bridge between particles (Ag and MWCNT-EDA), reducing the particle to particle resistivity. When inserted into polycarbonate, this three-phase blend successfully reduced the volume resistivity of the polymer by two orders of magnitude compared with previous approaches.

  2. Removal of Trace Arsenic to Meet Drinking Water Standards Using Iron Oxide Coated Multiwall Carbon Nanotubes.

    Science.gov (United States)

    Ntim, Susana Addo; Mitra, Somenath

    2011-05-12

    This study presents the removal of trace level arsenic to meet drinking water standards using an iron oxide-multi-walled carbon nanotube (Fe-MWCNT) hybrid as a sorbent. The synthesis was facilitated by the high degree of nanotube functionalization using a microwave assisted process, and a controlled assembly of iron oxide was possible where the MWCNT served as an effective support for the oxide. In the final product, 11 % of the carbon atoms were attached to Fe. The Fe-MWCNT was effective in arsenic removal to below the drinking water standard levels of 10 µg L(-1). The absorption capacity of the composite was 1723 µg g(-1) and 189 µg g(-1) for As(III) and As(V) respectively. The adsorption of As(V) on Fe-MWCNT was faster than that of As(III). The pseudo-second order rate equation was found to effectively describe the kinetics of arsenic adsorption. The adsorption isotherms for As(III) and As(V) fitted both the Langmuir and Freundlich models.

  3. Investigating the Inter-Tube Conduction Mechanism in Polycarbonate Nanocomposites Prepared with Conductive Polymer-Coated Carbon Nanotubes

    KAUST Repository

    Ventura, Isaac Aguilar

    2015-12-16

    A well-known strategy to improve the electrical conductivity of polymers is to dope them with high-aspect-ratio and conductive nanoparticles such as carbon nanotubes (CNTs). However, these nanocomposites also exhibit undesirable properties such as damage-sensitive and history-dependent conductivity because their macroscopic electrical conductivity is largely determined by the tunneling effect at the tube/tube interface. To reduce these issues, new nanocomposites have been developed with CNTs that have been coated with a conductive layer of poly(3,4-ethylenedioxythiophene)poly(styrenesulfonate) (PEDOT/PSS). It has been posited that the insulating region between the CNTs is replaced by a conductive polymer bridge; this has not been proven up to now. We propose here to investigate in-depth how the macroscopic conductivity of these materials is changing when (1) varying the frequency of the electrical loading (impedance spectroscopy), (2) varying the mechanical hydrostatic pressure, and (3) varying the voltage of the electrical loading. The response is systematically compared to the one of conventional carbon nanotube/polycarbonate (CNT/PC) nanocomposites so we can clarify how efficiently the tunneling effect is suppressed from these composites. The objective is to elucidate further the mechanism for conduction in such material formulations.

  4. Facile synthesis of titania nanoparticles coated carbon nanotubes for selective enrichment of phosphopeptides for mass spectrometry analysis.

    Science.gov (United States)

    Yan, Yinghua; Lu, Jin; Deng, Chunhui; Zhang, Xiangmin

    2013-03-30

    In this work, titania nanoparticles coated carbon nanotubes (denoted as CNTs/TiO2 composites) were synthesized through a facile but effective solvothermal reaction using titanium isopropoxide as the titania source, isopropyl alcohol as the solvent and as the basic catalyst in the presence of hydrophilic carbon nanotubes. Characterizations using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) indicate that the CNTs/TiO2 composites consist of CNT core and a rough outer layer formed by titania nanoparticles (5-10nm). Measurements using wide angle X-ray diffraction (WAXRD), zeta potential and N2 sorption reveal that the titania shell is formed by anatase titania nanoparticles, and the composites have a high specific surface area of about 104 m(2)/g. By using their high surface area and affinity to phosphopeptides, the CNTs/TiO2 composites were applied to selectively enrich phosphopeptides for mass spectrometry analysis. The high selectivity and capacity of the CNTs/TiO2 composites have been demonstrated by effective enrichment of phosphopeptides from digests of phosphoprotein, protein mixtures of β-casein and bovine serum albumin, human serum and rat brain samples. These results foresee a promising application of the novel CNTs/TiO2 composites in the selective enrichment of phosphopeptides. Copyright © 2013 Elsevier B.V. All rights reserved.

  5. Carbon nanotubes cement composites

    OpenAIRE

    Simone Musso; Jean-Marc Tulliani; Giuseppe Ferro

    2011-01-01

    The present paper reviews the current state of the art of carbon nanotubes cement-based composites and the possible applications. The influence of carbon nanotubes additions onto cement paste mechanical and electrical properties are discussed in detail. Though promising, several challenges have still to be solved before the introduction of these new materials into the public sphere through civil infrastructures.

  6. Multiwall Carbon Nanotube Coated with Conducting Polyaniline Nanocomposites for Quasi-Solid-State Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Mohammad Rezaul Karim

    2013-01-01

    Full Text Available Multiwalled carbon nanotube (MWNT coated with conducting polyaniline (PAni nanocomposites has been enforced as for quasi-solid-state electrolyte layer in the dye-sensitized solar cells (DSSCs, and the incorporation of MWNT-PAni nanoparticles on the cell performance has been examined. The MWNT-PAni nanoparticles exploited as the extended electron transfer materials, which can reduce charge diffusion length and serve simultaneously as catalyst for the electrochemical reduction of I3-. An ionic liquid of 1-methyl-3-propyl-imidazolium iodide (PMII together with the hybrid MWNT-PAni nanocomposites was placed between the dye-sensitized porous TiO2 and the Pt counter electrode without adding iodine and achieved a moderately higher cell efficiency (3.15%, as compared to that containing bare PMII (0.26%.

  7. Secondary doping in polyaniline layers coated on multi-walled carbon nanotubes

    Directory of Open Access Journals (Sweden)

    Zhou Yi

    2015-01-01

    Full Text Available HC1 doped coaxial polyaniline/multiwalled carbon nanotubes (MWCNTs nanocomposites were first prepared by in–situ chemical polymerization of aniline monomers in the presence of MWCNTs with less structural defects. P-toluene sulfonic acid (TSA and 5-sulfosalicylic acid dihydrate (SSA redoped PANI/MWCNT nanocomposites were achieved after the as-prepared nanocomposites were treated by ammonia respectively. The redoped nanocomposites were characterized by field emission scanning electron microscopy, transmission electron microscopy, fourier transform infrared spectroscopy, Raman, X–ray diffraction, thermogravimetric analysis and cyclic voltammetry, respectively. The results indicated that the thermal stability and electrochemical behaviour of TSA doped PANI/MWCNT nanocomposites were better than that of SSA doped PANI/MWCNT nanocomposites.

  8. A Flexible and Highly Sensitive Piezoresistive Pressure Sensor Based on Micropatterned Films Coated with Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Jia-lin Yao

    2016-01-01

    Full Text Available Excellent flexibility, high sensitivity, and low consumption are essential characteristics in flexible microtube pressure sensing occasion, for example, implantable medical devices, industrial pipeline, and microfluidic chip. This paper reports a flexible, highly sensitive, and ultrathin piezoresistive pressure sensor for fluid pressure sensing, whose sensing element is micropatterned films with conductive carbon nanotube layer. The flexible pressure sensor, the thickness of which is 40 ± 10 μm, could be economically fabricated by using biocompatible polydimethylsiloxane (PDMS. Experimental results show that the flexible pressure sensor has high sensitivity (0.047 kPa−1 in gas sensing and 5.6 × 10−3 kPa−1 in liquid sensing and low consumption (<180 μW, and the sensor could be used to measure the pressure in curved microtubes.

  9. Electron field emission characteristics of different surface morphologies of ZnO nanostructures coated on carbon nanotubes.

    Science.gov (United States)

    Li, Kuan-Wei; Lian, Huan-Bin; Cai, Jhen-Hong; Wang, Yao-Te; Lee, Kuei-Yi

    2011-12-01

    The optimal carbon nanotube (CNT) bundles with a hexagonal arrangement were synthesized using thermal chemical vapor deposition (TCVD). To enhance the electron field emission characteristics of the pristine CNTs, the zinc oxide (ZnO) nanostructures coated on CNT bundles using another TCVD technique. Transmission electron microscopy (TEM) images showed that the ZnO nanostructures were grown onto the CNT surface uniformly, and the surface morphology of ZnO nanostructures varied with the distance between the CNT bundle and the zinc acetate. The results of field emissions showed that the ZnO nanostructures grown onto the CNTs could improve the electron field emission characteristics. The enhancement of field emission characteristics was attributed to the increase of emission sites formed by the nanostructures of ZnO grown onto the CNT surface, and each ZnO nanostructure could be regarded as an individual field emission site. In addition, ZnO-coated CNT bundles exhibited a good emission uniformity and stable current density. These results demonstrated that ZnO-coated CNTs is a promising field emitter material.

  10. Purification of carbon nanotubes via selective heating

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, John A.; Wilson, William L.; Jin, Sung Hun; Dunham, Simon N.; Xie, Xu; Islam, Ahmad; Du, Frank; Huang, Yonggang; Song, Jizhou

    2017-11-21

    The present invention provides methods for purifying a layer of carbon nanotubes comprising providing a precursor layer of substantially aligned carbon nanotubes supported by a substrate, wherein the precursor layer comprises a mixture of first carbon nanotubes and second carbon nanotubes; selectively heating the first carbon nanotubes; and separating the first carbon nanotubes from the second carbon nanotubes, thereby generating a purified layer of carbon nanotubes. Devices benefiting from enhanced electrical properties enabled by the purified layer of carbon nanotubes are also described.

  11. Facile template-directed synthesis of carbon-coated SnO{sub 2} nanotubes with enhanced Li-storage capabilities

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Xiaoshu; Zhu, Jingyi; Yao, Yinan; Zhou, Yiming; Tang, Yawen; Wu, Ping, E-mail: zjuwuping@njnu.edu.cn

    2015-08-01

    Herein, a novel type of carbon-coated SnO{sub 2} nanotubes has been designed and synthesized through a facile two-step hydrothermal approach by using ZnO nanorods as templates. During the synthetic route, SnO{sub 2} nanocrystals and carbon layer have been uniformly deposited on the rod-like templates in sequence, meanwhile ZnO nanorods could be in situ dissolved owing to the generated alkaline and acidic environments during hydrothermal coating of SnO{sub 2} nanocrystals and hydrothermal carbonization of glucose, respectively. When utilized as an anode material in lithium-ion batteries, the carbon-coated SnO{sub 2} nanotubes manifests markedly enhanced Li-storage capabilities in terms of specific capacity and cycling stability in comparison with bare SnO{sub 2} nanocrystals. - Graphical abstract: Display Omitted - Highlights: • C-coated SnO{sub 2} nanotubes prepared via facile ZnO-nanorod-templated hydrothermal route. • Unique morphological and structural features toward lithium storage. • Enhanced Li-storage performance in terms of specific capacity and cycling stability.

  12. Enhanced photoelectrochemical water splitting performance of TiO2 nanotube arrays coated with an ultrathin nitrogen-doped carbon film by molecular layer deposition.

    Science.gov (United States)

    Tong, Xili; Yang, Peng; Wang, Yunwei; Qin, Yong; Guo, Xiangyun

    2014-06-21

    Vertically oriented TiO2 nanotube arrays (TNTAs) were conformally coated with an ultrathin nitrogen-doped (N-doped) carbon film via the carbonization of a polyimide film deposited by molecular layer deposition and simultaneously hydrogenated, thereby creating a core/shell nanostructure with a precisely controllable shell thickness. The core/shell nanostructure provides a larger heterojunction interface to substantially reduce the recombination of photogenerated electron-hole pairs, and hydrogenation enhances solar absorption of TNTAs. In addition, the N-doped carbon film coating acts as a high catalytic active surface for oxygen evolution reaction, as well as a protective film to prevent hydrogen-treated TiO2 nanotube oxidation by electrolyte or air. As a result, the N-doped carbon film coated TNTAs displayed remarkably improved photocurrent and photostability. The TNTAs with a N-doped carbon film of ∼ 1 nm produces a current density of 3.6 mA cm(-2) at 0 V vs. Ag/AgCl under the illumination of AM 1.5 G (100 mW cm(-2)), which represents one of the highest values achieved with modified TNTAs. Therefore, we propose that ultrathin N-doped carbon film coating on materials is a viable approach to enhance their PEC water splitting performance.

  13. As(III) and As(V) adsorption on nanocomposite of hydrated zirconium oxide coated carbon nanotubes.

    Science.gov (United States)

    Liu, Dengchao; Deng, Shubo; Maimaiti, Ayiguli; Wang, Bin; Huang, Jun; Wang, Yujue; Yu, Gang

    2018-02-01

    Novel hydrated zirconium oxide (ZrO(OH)2) coated carbon nanotubes (CNTs) were prepared via a filtration-steam hydrolysis method, and were used to remove As(III) and As(V) from drinking water. This adsorbent was characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM). The ZrO(OH)2 coated on the surface of CNTs was amorphous, and the coating thickness was in the range of 1-8 nm. The ZrO(OH)2/CNTs nanocomposite showed high adsorption for both As(III) and As(V) with the maximum adsorption capacities of 78.2 and 124.6 mg/g, respectively, according to the Langmuir fitting. The adsorption capacities of ZrO(OH)2/CNTs at the equilibrium concentration of 10 μg/L were 2.0 mg/g for As(III) and 7.2 mg/g for As(V) at pH 7, much higher than those of ZrO(OH)2 nanoparticles. Meanwhile, the adsorption rates of As(III) and As(V) on the ZrO(OH)2/CNTs were higher than the ZrO(OH)2 nanoparticles. The spent adsorbent can be regenerated by re-coating ZrO(OH)2 as the preparation method, and the adsorbed amounts of As(III) and As(V) on the ZrO(OH)2/CNTs changed little within six cycles. This ZrO(OH)2/CNTs nanocomposite shows a promising application potential for the removal of As(III) and As(V) from drinking water. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Multifunctional Carbon Nanotube Fiber Composites

    Science.gov (United States)

    2004-12-26

    First, both sides of the membrane were sputter-coated with a thin layer of platinum. On one side, a thin film of CNT was next deposited by filtration...absorption spectra of thin films or solutions containing predominantly aggregated SWNTs are dominated by inhomogeneously broadened optical transitions...electrochemical actuation. This objective was attained by welding carbon nanotube structures with polymer derived ceramic (PDC), silicon carbonitride (SiCN

  15. Carbon nanotube macroelectronics

    Science.gov (United States)

    Zhang, Jialu

    In this dissertation, I discuss the application of carbon nanotubes in macroelectronis. Due to the extraordinary electrical properties such as high intrinsic carrier mobility and current-carrying capacity, single wall carbon nanotubes are very desirable for thin-film transistor (TFT) applications such as flat panel display, transparent electronics, as well as flexible and stretchable electronics. Compared with other popular channel material for TFTs, namely amorphous silicon, polycrystalline silicon and organic materials, nanotube thin-films have the advantages of low-temperature processing compatibility, transparency, and flexibility, as well as high device performance. In order to demonstrate scalable, practical carbon nanotube macroelectroncis, I have developed a platform to fabricate high-density, uniform separated nanotube based thin-film transistors. In addition, many other essential analysis as well as technology components, such as nanotube film density control, purity and diameter dependent semiconducting nanotube electrical performance study, air-stable n-type transistor fabrication, and CMOS integration platform have also been demonstrated. On the basis of the above achievement, I have further demonstrated various kinds of applications including AMOLED display electronics, PMOS and CMOS logic circuits, flexible and transparent electronics. The dissertation is structured as follows. First, chapter 1 gives a brief introduction to the electronic properties of carbon nanotubes, which serves as the background knowledge for the following chapters. In chapter 2, I will present our approach of fabricating wafer-scale uniform semiconducting carbon nanotube thin-film transistors and demonstrate their application in display electronics and logic circuits. Following that, more detailed information about carbon nanotube thin-film transistor based active matrix organic light-emitting diode (AMOLED) displays is discussed in chapter 3. And in chapter 4, a technology to

  16. An effective route for the room temperature formation of Pd coatings on multiwalled carbon nanotubes in aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yeong Joon [Dept. of Chemistry, Chungnam National University, Daejeon (Korea, Republic of); Lee, Im Kyu; Song, Jae Hee [Dept. of Chemistry, Sunc hon National University, Suncheon (Korea, Republic of)

    2016-10-15

    We present an easy one-pot synthesis route for the production of palladium nanoparticles and multiwalled carbon nanotubes (MWCNTs)-supported Pd-nanomaterial composites by a simple proton beam irradiation process in an aqueous solution at room temperature. Pristine and surface-modified MWCNTs were used to prepare MWCNT–Pd hybrids. Pd nanoparticles on the surfaces of MWCNTs were produced in situ in an aqueous solution without the addition of any harsh reducing agent. Pristine and thiolated MWCNTs were both densely decorated with spherical Pd nanoparticles and eventually Pd nanowire formation on MWCNTs was realized when reaction times exceeded 60 min. The thicknesses of Pd coatings on MWCNT surfaces were controlled by varying the concentration of MWCNTs in the reaction mixture. MWCNT-Pd composites were characterized by time-resolved transmission electron microscopy, selected area electron diffraction, and energy dispersive X-ray spectroscopy, and the results obtained showed that Pd coatings were continuous, and resulted in a MWCNT-supported Pd nanowire structure.

  17. Polydopamine Coated Single-Walled Carbon Nanotubes as a Versatile Platform with Radionuclide Labeling for Multimodal Tumor Imaging and Therapy.

    Science.gov (United States)

    Zhao, He; Chao, Yu; Liu, Jingjing; Huang, Jie; Pan, Jian; Guo, Wanliang; Wu, Jizhi; Sheng, Mao; Yang, Kai; Wang, Jian; Liu, Zhuang

    2016-01-01

    Single-walled carbon nanotubes (SWNTs) with various unique properties have attracted great attention in cancer theranostics. Herein, SWNTs are coated with a shell of polydopamine (PDA), which is further modified by polyethylene glycol (PEG). The PDA shell in the obtained SWNT@PDA-PEG could chelate Mn(2+), which together with metallic nanoparticulate impurities anchored on SWNTs offer enhanced both T1 and T2 contrasts under magnetic resonance (MR) imaging. Meanwhile, also utilizing the PDA shell, radionuclide (131)I could be easily labeled onto SWNT@PDA-PEG, enabling nuclear imaging and radioisotope cancer therapy. As revealed by MR & gamma imaging, efficient tumor accumulation of SWNT@PDA-(131)I-PEG is observed after systemic administration into mice. By further utilizing the strong near-infarared (NIR) absorbance of SWNTs, NIR-triggered photothermal therapy in combination with (131)I-based radioisotope therapy is realized in our animal experiments, in which a remarkable synergistic antitumor therapeutic effect is observed compared to monotherapies. Our work not only presents a new type of theranostic nanoplatform based on SWNTs, but also suggests the promise of PDA coating as a general approach to modify nano-agents and endow them with highly integrated functionalities.

  18. Multiwalled carbon nanotubes-doped polymeric ionic liquids coating for multiple headspace solid-phase microextraction.

    Science.gov (United States)

    Feng, Juanjuan; Sun, Min; Li, Leilei; Wang, Xiaojiao; Duan, Huimin; Luo, Chuannan

    2014-06-01

    Multiple headspace solid-phase microextraction (SPME) has proved high efficiency in analysis of volatile compounds in complex samples. Fibers used in multiple headspace SPME must provide a logarithm relationship between peak areas and extraction times. The aim of this work was to investigate the potential of a carbon nanotube doped-polymeric ionic liquid (PILs) fiber for multiple headspace SPME of 2-naphthol in fruit samples, using gas chromatography (GC) for analysis. Based on theory of multiple headspace SPME, β parameters of fruit and aqueous samples were obtained and used for quantitation. The interference effects of sample matrix on proposed multiple headspace SPME method were investigated and compared with that of headspace SPME by determination of significant differences (P) of peak areas. It showed high independence from matrix effects. The proposed multiple headspace SPME-GC method also exhibited high repeatability (relative standard deviation of 2.56%) and recoveries (81.9-110%) for the analysis of real samples. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Novel polydopamine imprinting layers coated magnetic carbon nanotubes for specific separation of lysozyme from egg white.

    Science.gov (United States)

    Gao, Ruixia; Zhang, Lili; Hao, Yi; Cui, Xihui; Liu, Dechun; Zhang, Min; Tang, Yuhai

    2015-11-01

    Novel core-shell nanocomposites, consisting of magnetic carbon nanotubes (MCNTs) core surrounded by a thin polydopamine (PDA) imprinting shell for specific recognition of lysozyme (Lyz), were fabricated for the first time. The obtained products were characterized and the results showed that the PDA layer was successfully attached onto the surface of MCNTs and the corresponding thickness of imprinting layer was just about 10nm which could enable the template access the recognition cavities easily. The polymerization conditions and adsorption performance of the resultant nanomaterials were investigated in detail. The results indicated that the obtained imprinted polymers showed fast kinetic and high affinity towards Lyz and could be used to specifically separate Lyz from real egg white. In addition, the prepared materials had excellent stability and no obvious deterioration after five adsorption-regeneration cycles. Easy preparation, rapid separation, high binding capacity, and satisfactory selectivity for the template protein make this polymer attractive in biotechnology and biosensors. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Nanoconfined phosphorus film coating on interconnected carbon nanotubes as ultrastable anodes for lithium ion batteries

    Science.gov (United States)

    Xu, Zhiwei; Zeng, Yan; Wang, Liyuan; Li, Nan; Chen, Cheng; Li, Cuiyu; Li, Jing; Lv, Hanming; Kuang, Liyun; Tian, Xu

    2017-07-01

    Elemental phosphorus (P) is extensively explored as promising anode candidates due to its abundance, low-cost and high theoretical specific capacity. However, it is of great challenge for P-based materials as practical high-energy-density and long-cycling anodes for its large volume expansion and low conductibility. Here, we significantly improve both cycling and rate performance of red P by cladding the nanoconfined P film on interconnected multi-walled carbon nanotube networks (P-MWCNTs composite) via facile wet ball-milling. The red P-MWCNTs anode presents a superior high reversible capacity of 1396.6 mAh g-1 on the basis of P-MWCNTs composite weight at 50 mA g-1 with capacity retention reaching at ∼90% over 50 cycles. Even at 1000 mA g-1, it still maintains remarkable specific reversible capacity of 934.0 mAh g-1. This markedly enhanced performance is ascribed to synergistic advantages of this unique structure: Intimate contacts between nanosized red P and entangled MWCNTs not only shorten the transmission routes of ions through MWCNTs toward red P, but also motivate the access with electrolyte to open structures of P film. Besides, the confined nanosized P film moderate volume expansions effectively and the entangled MWCNTs networks acted as conductive channels activate high ionic/electronic conductivity of the whole electrodes.

  1. Miniemulsion copolymerization of (methacrylates in the presence of functionalized multiwalled carbon nanotubes for reinforced coating applications

    Directory of Open Access Journals (Sweden)

    Bertha T. Pérez-Martínez

    2017-06-01

    Full Text Available Film forming, stable hybrid latexes made of methyl metacrylate (MMA, butyl acrylate (BA and 2-hydroxyethyl methacrylate (HEMA copolymer reinforced with modified multiwalled carbon nanotubes (MWCNTs were synthesized by in situ miniemulsion polymerization. The MWCNTs were pretreated by an air sonication process and stabilized by polyvinylpyrrolidone. The presence of the MWCNTs had no significant effect on the polymerization kinetics, but strongly affected the polymer characteristics (Tg and insoluble polymer fraction. The performance of the in situ composites was compared with that of the neat polymer dispersion as well as with those of the polymer/MWCNT physical blends. The in situ composites showed the presence of an additional phase likely due to the strong interaction between the polymer and MWNCTs (including grafting that reduced the mobility of the polymer chains. As a result, a substantial increase of both the storage and the loss moduli was achieved. At 60 °C, which is above the main transition region of the polymer, the in situ composites maintained the reinforcement, whereas the blends behaved as a liquid-like material. This suggests the formation of a 3D network, in good agreement with the high content of insoluble polymer in the in situ composites.

  2. Transport in Carbon Nanotubes

    Science.gov (United States)

    Datta, S.; Xue, Yong-Qinag; Anantram, M. P.; Saini, Subhash (Technical Monitor)

    1999-01-01

    This presentation discusses coupling between carbon nanotubes (CNT), simple metals (FEG) and a graphene sheet. The graphene sheet did not couple well with FEG, but the combination of a graphene strip and CNT did couple well with most simple metals.

  3. Carbon nanotubes for supercapacitor

    National Research Council Canada - National Science Library

    Pan, Hui; Li, Jianyi; Feng, Yuanping

    2010-01-01

    .... 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...

  4. Carbon nanotube biosensors

    National Research Council Canada - National Science Library

    Tîlmaciu, Carmen-Mihaela; Morris, May C

    2015-01-01

    .... 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...

  5. Morphing Carbon Nanotube Microstructures

    Science.gov (United States)

    2015-02-20

    muscle inspired by spider dragline silk. Nat. Commun. 5, 3322 (2014). 13. Hart, A. J. & Slocum , A. H. Rapid Growth and Flow-Mediated Nucleation of...Phys. Lett. 87, 123110 (2005). 15. A. J. Hart, A. H. Slocum . Rapid growth and flow-mediated nucleation of millimeter-scale aligned carbon nanotube... Slocum , B. L. Wardle. High-yield growth and morphology control of aligned carbon nanotubes on ceramic fibers for multifunctional enhancement of

  6. Carbon Nanotubes in Neuroscience

    OpenAIRE

    Malarkey, Erik B.; Parpura, Vladimir

    2010-01-01

    Carbon nanotubes have electrical, mechanical and chemical properties that make them one of the most promising materials for applications in neuroscience. Single-walled and multi-walled carbon nanotubes have been increasingly used as scaffolds for neuronal growth and more recently for neural stem cell growth and differentiation. They are also used in interfaces with neurons, where they can detect neuronal electrical activity and also deliver electrical stimulation to these cells. The emerging ...

  7. Removals of aqueous sulfur dioxide and hydrogen sulfide using CeO2-NiAl-LDHs coating activated carbon and its mix with carbon nano-tubes

    KAUST Repository

    Li, Jing

    2015-07-01

    Ce-doped NiAl/layered double hydroxide was coated at activated carbon by urea hydrolysis method (CeO2-NiAl-LDHs/AC) in one pot, which was characterized by X-ray diffraction, infrared spectra, field emission scanning electron microscope and electrochemical techniques. CeO2-NiAl-LDHs/AC shows good uptake for aqueous sulfur dioxide (483.09mg/g) and hydrogen sulfide (181.15mg/g), respectively at 25°C. Meanwhile, the electrochemical removals of aqueous sulfur dioxide and hydrogen sulfide were respectively investigated at the mix of CeO2-NiAl-LDHs/AC and carbon nano-tubes modified homed paraffin-impregnated electrode. Both sulfur dioxide and hydrogen sulfide could be effectively oxidized to sulfuric acid at 1.0V in alkaline aqueous solution. © 2015 Elsevier B.V.

  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. Bioactivity and electrochemical behavior of hydroxyapatite-silicon-multi walled carbon nano-tubes composite coatings synthesized by EPD on NiTi alloys in simulated body fluid.

    Science.gov (United States)

    Khalili, V; Khalil-Allafi, J; Frenzel, J; Eggeler, G

    2017-02-01

    In order to improve the surface bioactivity of NiTi bone implant and corrosion resistance, hydroxyapatite coating with addition of 20wt% silicon, 1wt% multi walled carbon nano-tubes and both of them were deposited on a NiTi substrate using a cathodic electrophoretic method. The apatite formation ability was estimated using immersion test in the simulated body fluid for 10days. The SEM images of the surface of coatings after immersion in simulated body fluid show that the presence of silicon in the hydroxyapatite coatings accelerates in vitro growth of apatite layer on the coatings. The Open-circuit potential and electrochemical impedance spectroscopy were measured to evaluate the electrochemical behavior of the coatings in the simulated body fluid at 37°C. The results indicate that the compact structure of hydroxyapatite-20wt% silicon and hydroxyapatite-20wt% silicon-1wt% multi walled carbon nano-tubes coatings could efficiently increase the corrosion resistance of NiTi substrate. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Multiwalled carbon nanotube coated polyester fabric as textile based flexible counter electrode for dye sensitized solar cell.

    Science.gov (United States)

    Arbab, Alvira Ayoub; Sun, Kyung Chul; Sahito, Iftikhar Ali; Qadir, Muhammad Bilal; Jeong, Sung Hoon

    2015-05-21

    Textile wearable electronics offers the combined advantages of both electronics and textile characteristics. The essential properties of these flexible electronics such as lightweight, stretchable, and wearable power sources are in strong demand. Here, we have developed a facile route to fabricate multi walled carbon nanotube (MWCNT) coated polyester fabric as a flexible counter electrode (CE) for dye sensitized solar cells (DSSCs). A variety of MWCNT and enzymes with different structures were used to generate individual enzyme-dispersed MWCNT (E-MWCNT) suspensions by non-covalent functionalization. A highly concentrated colloidal suspension of E-MWCNT was deposited on polyester fabric via a simple tape casting method using an air drying technique. In view of the E-MWCNT coating, the surface structure is represented by topologically randomly assembled tubular graphene units. This surface morphology has a high density of colloidal edge states and oxygen-containing surface groups which execute multiple catalytic sites for iodide reduction. A highly conductive E-MWCNT coated fabric electrode with a surface resistance of 15 Ω sq(-1) demonstrated 5.69% power conversion efficiency (PCE) when used as a flexible CE for DSSCs. High photo voltaic performance of our suggested system of E-MWCNT fabric-based DSSCs is associated with high sheet conductivity, low charge transfer resistance (RCT), and excellent electro catalytic activity (ECA). Such a conductive fabric demonstrated stable conductivity against bending cycles and strong mechanical adhesion of E-MWCNT on polyester fabric. Moreover, the polyester fabric is hydrophobic and, therefore, has good sealing capacity and retains the polymer gel electrolyte without seepage. This facile E-MWCNT fabric CE configuration provides a concrete fundamental background towards the development of textile-integrated solar cells.

  11. Coating carbon nanotubes with humic acid using an eco-friendly mechanochemical method: Application for Cu(II) ions removal from water and aquatic ecotoxicity.

    Science.gov (United States)

    Côa, Francine; Strauss, Mathias; Clemente, Zaira; Rodrigues Neto, Laís L; Lopes, Josias R; Alencar, Rafael S; Souza Filho, Antônio G; Alves, Oswaldo L; Castro, Vera Lúcia S S; Barbieri, Edison; Martinez, Diego Stéfani T

    2017-12-31

    In this work, industrial grade multi-walled carbon nanotubes (MWCNT) were coated with humic acid (HA) for the first time by means of a milling process, which can be considered an eco-friendly mechanochemical method to prepare materials and composites. The HA-MWCNT hybrid material was characterized by atomic force microscopy (AFM), scanning electron microscopies (SEM and STEM), X-ray photoelectron spectroscopy (XPS), termogravimetric analysis (TGA), and Raman spectroscopy. STEM and AFM images demonstrated that the MWCNTs were efficiently coated by the humic acid, thus leading to an increase of 20% in the oxygen content at the nanotube surface as observed by the XPS data. After the milling process, the carbon nanotubes were shortened as unveiled by SEM images and the values of ID/IG intensity ratio increased due to shortening of the nanotubes and increasing in the number defects at the graphitic structure of carbon nanotubes walls. The analysis of TGA data showed that the quantity of the organic matter of HA on the nanotube surface was 25%. The HA coating was responsible to favor the dispersion of MWCNTs in ultrapure water (i.e. -42mV, zeta-potential value) and to improve their capacity for copper removal. HA-MWCNTs hybrid material adsorbed 2.5 times more Cu(II) ions than oxidized MWCNTs with HNO3, thus evidencing that it is a very efficient adsorbent material for removing copper ions from reconstituted water. The HA-MWCNTs hybrid material did not show acute ecotoxicity to the tested aquatic model organisms (Hydra attenuata, Daphnia magna, and Danio rerio embryos) up to the highest concentration evaluated (10mgL-1). The results allowed concluding that the mechanochemical method is effective to coat carbon nanotubes with humic acid, thus generating a functional hybrid material with low aquatic toxicity and great potential to be applied in environmental nanotechnologies such as the removal of heavy metal ions from water. Copyright © 2017 Elsevier B.V. All rights

  12. Label-free SERS detection of relevant bioanalytes on silver-coated carbon nanotubes: The case of cocaine

    Science.gov (United States)

    Sanles-Sobrido, Marcos; Rodríguez-Lorenzo, Laura; Lorenzo-Abalde, Silvia; González-Fernández, África; Correa-Duarte, Miguel A.; Alvarez-Puebla, Ramón A.; Liz-Marzán, Luis M.

    2009-09-01

    Surface-enhanced Raman scattering (SERS) spectroscopy can be used for the label-free determination and quantification of relevant small biometabolites that are hard to identify by conventional immunological methods, in the absence of labelling. In this work, detection is based on monitoring the vibrational changes occurring at a specific biointerface (a monoclonal antibody, mAb) supported on silver-coated carbon nanotubes (CNT@Ag). Engineered CNT@Ag play a key role, as they offer a stable substrate to support the biointerface, with a high density of hot spots. Proof of concept is demonstrated through the analysis and quantification of the main cocaine metabolite benzoylecgonine. These results open a new avenue toward the generation of portable sensors for fast ultradetection and quantification of relevant metabolites. The use of discrete particles (CNT@Ag@mAb) rather than rough films, or other conventional SERS supports, will also enable a safe remote interrogation of highly toxic sources in environmental problems or in biological fluids.Surface-enhanced Raman scattering (SERS) spectroscopy can be used for the label-free determination and quantification of relevant small biometabolites that are hard to identify by conventional immunological methods, in the absence of labelling. In this work, detection is based on monitoring the vibrational changes occurring at a specific biointerface (a monoclonal antibody, mAb) supported on silver-coated carbon nanotubes (CNT@Ag). Engineered CNT@Ag play a key role, as they offer a stable substrate to support the biointerface, with a high density of hot spots. Proof of concept is demonstrated through the analysis and quantification of the main cocaine metabolite benzoylecgonine. These results open a new avenue toward the generation of portable sensors for fast ultradetection and quantification of relevant metabolites. The use of discrete particles (CNT@Ag@mAb) rather than rough films, or other conventional SERS supports, will also

  13. Enhanced Flux and Electrochemical Cleaning of Silicate Scaling on Carbon Nanotube-Coated Membrane Distillation Membranes Treating Geothermal Brines

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Li [Department; Iddya, Arpita [Department; Zhu, Xiaobo [Department; Dudchenko, Alexander V. [Department; Duan, Wenyan [Department; Turchi, Craig [Department; Vanneste, Johann [Department; Cath, Tzahi Y. [Department; Jassby, David [Department

    2017-10-24

    The desalination of inland brackish groundwater offers the opportunity to provide potable drinking water to residents and industrial cooling water to industries located in arid regions. Geothermal brines are used to generate electricity, but often contain high concentrations of dissolved salt. Here, we demonstrate how the residual heat left in spent geothermal brines can be used to drive a membrane distillation (MD) process and recover desalinated water. Porous polypropylene membranes were coated with a carbon nanotube (CNT)/poly(vinyl alcohol) layer, resulting in composite membranes having a binary structure that combines the hydrophobic properties critical for MD with the hydrophilic and conductive properties of the CNTs. We demonstrate that the addition of the CNT layer increases membrane flux due to enhanced heat transport from the bulk feed to the membrane surface, a result of CNT's high thermal transport properties. Furthermore, we show how hydroxide ion generation, driven by water electrolysis on the electrically conducting membrane surface, can be used to efficiently dissolve silicate scaling that developed during the process of desalinating the geothermal brine, negating the need for chemical cleaning.

  14. Direct electron transfer and electrocatalysis of hemoglobin in ZnO coated multiwalled carbon nanotubes and Nafion composite matrix.

    Science.gov (United States)

    Ma, Wei; Tian, Danbi

    2010-06-01

    ZnO coated multiwalled carbon nanotubes (ZnO-MWCNTs) nano-composite was synthesized by the hydrothermal method and expected to offer a promising template for biosensor fabrication due to satisfying biocompatibility and improved properties. The ZnO-MWCNTs nano-composite was mixed with Nafion solution to form a composite matrix for the fabrication of hemoglobin (Hb) biosensor. This composite matrix combined the advantages of inorganic composite (ZnO-MWCNTs) and organic polymer (Nafion) and could promote the direct electron transfer of Hb. The Hb/ZnO-MWCNTs/Nafion film exhibited a pair of well-defined, quasi-reversible redox peaks with a formal potential of -0.353V (vs. SCE), characteristic of heme redox couple (Fe(III)/Fe(II)) of Hb. Hb retained its near-native conformation in the composite film. The immobilized Hb showed fast and excellent electrocatalytic activity to H(2)O(2) with a linear range from 2x10(-7) to 1.2x10(-5)M, and the detection limit was 8.4x10(-8)M. The sensitivity and apparent Michaelis-Menten constant were 1.31A/(M x cm(2)) and 82.8microM, respectively, which indicated that Hb had a high affinity to H(2)O(2). This biosensor also showed excellent electrocatalytic activity towards trichloroacetic acid. Crown Copyright 2009. Published by Elsevier B.V. All rights reserved.

  15. Fabrication of enzyme-based coatings on intact multi-walled carbon nanotubes as highly effective electrodes in biofuel cells

    Science.gov (United States)

    Kim, Byoung Chan; Lee, Inseon; Kwon, Seok-Joon; Wee, Youngho; Kwon, Ki Young; Jeon, Chulmin; An, Hyo Jin; Jung, Hee-Tae; Ha, Su; Dordick, Jonathan S.; Kim, Jungbae

    2017-01-01

    CNTs need to be dispersed in aqueous solution for their successful use, and most methods to disperse CNTs rely on tedious and time-consuming acid-based oxidation. Here, we report the simple dispersion of intact multi-walled carbon nanotubes (CNTs) by adding them directly into an aqueous solution of glucose oxidase (GOx), resulting in simultaneous CNT dispersion and facile enzyme immobilization through sequential enzyme adsorption, precipitation, and crosslinking (EAPC). The EAPC achieved high enzyme loading and stability because of crosslinked enzyme coatings on intact CNTs, while obviating the chemical pretreatment that can seriously damage the electron conductivity of CNTs. EAPC-driven GOx activity was 4.5- and 11-times higher than those of covalently-attached GOx (CA) on acid-treated CNTs and simply-adsorbed GOx (ADS) on intact CNTs, respectively. EAPC showed no decrease of GOx activity for 270 days. EAPC was employed to prepare the enzyme anodes for biofuel cells, and the EAPC anode produced 7.5-times higher power output than the CA anode. Even with a higher amount of bound non-conductive enzymes, the EAPC anode showed 1.7-fold higher electron transfer rate than the CA anode. The EAPC on intact CNTs can improve enzyme loading and stability with key routes of improved electron transfer in various biosensing and bioelectronics devices.

  16. Manganese Oxide-Coated Carbon Nanotubes As Dual-Modality Lymph Mapping Agents for Photothermal Therapy of Tumor Metastasis.

    Science.gov (United States)

    Wang, Sheng; Zhang, Qin; Yang, Peng; Yu, Xiangrong; Huang, Li-Yong; Shen, Shun; Cai, Sanjun

    2016-02-17

    Lymph node (LN) status is a major indicator of stage and survival of lung cancer patients. LN dissection is a primary option for lung cancer LN metastasis; however, this strategy elicits adverse effects and great trauma. Therefore, developing a minimally invasive technique to cure LN metastasis of lung cancer is desired. In this study, multiwalled carbon nanotubes (MWNTs) coated with manganese oxide (MnO) and polyethylene glycol (PEG) (namely MWNTs-MnO-PEG) was employed as a lymphatic theranostic agent to diagnose and treat metastatic LNs. After single local injection and lymph drainage were performed, regional LNs were clearly mapped by T1-weighted magnetic resonance (MR) of MnO and dark dye imaging of MWNTs. Meanwhile, metastatic LNs could be simultaneously ablated by near-infrared (NIR) irradiation under the guidance of dual-modality mapping. The excellent result was obtained in mice bearing LNs metastasis models, showing that MWNTs-MnO-PEG as a multifunctional theranostic agent was competent for dual-modality mapping guided photothermal therapy of metastatic LNs.

  17. Enhanced Flux and Electrochemical Cleaning of Silicate Scaling on Carbon Nanotube-Coated Membrane Distillation Membranes Treating Geothermal Brines.

    Science.gov (United States)

    Tang, Li; Iddya, Arpita; Zhu, Xiaobo; Dudchenko, Alexander V; Duan, Wenyan; Turchi, Craig; Vanneste, Johann; Cath, Tzahi Y; Jassby, David

    2017-11-08

    The desalination of inland brackish groundwater offers the opportunity to provide potable drinking water to residents and industrial cooling water to industries located in arid regions. Geothermal brines are used to generate electricity, but often contain high concentrations of dissolved salt. Here, we demonstrate how the residual heat left in spent geothermal brines can be used to drive a membrane distillation (MD) process and recover desalinated water. Porous polypropylene membranes were coated with a carbon nanotube (CNT)/poly(vinyl alcohol) layer, resulting in composite membranes having a binary structure that combines the hydrophobic properties critical for MD with the hydrophilic and conductive properties of the CNTs. We demonstrate that the addition of the CNT layer increases membrane flux due to enhanced heat transport from the bulk feed to the membrane surface, a result of CNT's high thermal transport properties. Furthermore, we show how hydroxide ion generation, driven by water electrolysis on the electrically conducting membrane surface, can be used to efficiently dissolve silicate scaling that developed during the process of desalinating the geothermal brine, negating the need for chemical cleaning.

  18. Performance improvement induced by asymmetric Y2O3-coated device structure to carbon-nanotube-film based photodetectors

    Science.gov (United States)

    Wang, Fanglin; Xu, Haitao; Huang, Huixin; Ma, Ze; Wang, Sheng; Peng, Lian-Mao

    2017-11-01

    Film-based semiconducting carbon nanotube (CNT) photodetectors are promising candidates for industrial applications. However, unintentional doping from the environment such as water/oxygen (H2O/O2) redox, polymers, etc. changes the doping level of the CNT film. Here, we evaluate the performance of film-based barrier-free bipolar diodes (BFBDs), which are basically semiconducting CNT films asymmetrically contacted by perfect n-type ohmic contact (scandium, Sc) and p-type ohmic contact (palladium, Pd) at the two ends of the diode. We show that normal BFBD devices have large variances of forward current, reverse current, and photocurrent for different doping levels of the channel. We propose an asymmetric Y2O3-coated BFBD device in which the channel is covered by a layer of an Y2O3 film and an overlap between the Sc electrode and the Y2O3 film is designed. The Y2O3 film provides p-type doping to the channel. The overlap section increases the length of the base of the pn junction, and the diffusion current of holes is suppressed. In this way, the rectifier factors (current ratio when voltages are at +0.5 V and -0.5 V) of the asymmetric Y2O3-coated BFBD devices are around two orders of magnitude larger and the photocurrent generation is more stable compared to that of normal devices. Our results provide a way to conquer the influence of unintentional doping from the environment and suppress reverse current in pn diodes. This is beneficial to applications of CNT-based photodetectors and of importance for inspiring methods to improve the performances of devices based on other low dimensional materials.

  19. 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

  20. Carbon Nanotubes for Supercapacitor

    Science.gov (United States)

    2010-01-01

    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. PMID:20672061

  1. 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.

  2. 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.

  3. Behaviour of one-step spray-coated carbon nanotube supercapacitor in ambient light harvester circuit with printed organic solar cell and electrochromic display.

    Science.gov (United States)

    Tuukkanen, Sampo; Välimäki, Marja; Lehtimäki, Suvi; Vuorinen, Tiina; Lupo, Donald

    2016-03-09

    A printed energy harvesting and storage circuit powered by ambient office lighting and its use to power a printed display is reported. The autonomous device is composed of three printed electronic components: an organic photovoltaic module, a carbon-nanotubes-only supercapacitor and an electrochromic display element. Components are fabricated from safe and environmentally friendly materials, and have been fabricated using solution processing methods, which translate into low-cost and high-throughput manufacturing. A supercapacitor made of spray-coated carbon nanotube based ink and aqueous NaCl electrolyte was charged using a printed organic photovoltaic module exposed to office lighting conditions. The supercapacitor charging rate, self-discharge rate and display operation were studied in detail. The supercapacitor self-discharge rate was found to depend on the charging rate. The fully charged supercapacitor was used as a power source to run the electrochromic display over 50 times.

  4. 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

    2017-02-17

    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).

  5. Polymer functionalized single-walled carbon nanotube composites and semi-fluorinated quaternary ammonium polymer colloids and coatings

    Science.gov (United States)

    Paul, Abhijit

    Scope and Method of Study: Current study focused on understanding of "wetting" and "dewetting" phenomena between surfaces of single-walled carbon nanotubes (SWCNT) which are lightly grafted with polymer chains by reversible-deactivation radical polymerization, when they are mixed with matrix chains of the same architecture as grafts. Effects of grafts to matrix chain lengths on SWCNT dispersion in matrix polymers were studied by measuring electrical conductivity, glass transition temperature, and storage and loss moduli of nanocomposites. Another area of work was to design semi-fluorinated copolymers with core-shell morphology by emulsion polymerization, study their catalytic activities for hydrolyses of Paraoxon, a toxic insecticide, in the forms of both colloidal dispersions and films, and to characterize the surfaces of the films by atomic force microscopy and by dynamic contact angle measurements. Findings and Conclusions: The glass transition temperature ( Tg) of polystyrene (PS) filled with SWCNT grafted with PS of different lengths increased from 99 to 109 °C at 6 wt% of SWCNT followed by a plateau. The heat capacity (DeltaCp ) at Tg continued to decrease only for the smallest chain length grafted PS nanocomposites. SWCNT/PS nanocomposites had low electrical conductivity and showed no percolation threshold due to the thick polymer coatings. A key finding was that the SWCNT surface can accommodate only a fixed numbers of styrene units. Similar results on change in Tg were obtained for SWCNT/PMMA nanocomposites when molecular weight of matrix (Mmatrix) ≥ molecular weight of grafts (Mgraft). No change in DeltaCp was observed for SWCNT/PMMA nanocomposites. "Wetting" to "dewetting" occurred Mmatrix/ Mgraft ≈ 1. For Mmatrix > Mgraft, electrical conductivity of nanocomposites reached the value of 10-9 S cm-1 at 1.0 wt% nanotube loading and had percolation threshold of electrical conductivity at ˜0.25 wt% SWCNT. Raman and UV-vis-NIR data confirmed that

  6. Preparation and characterization of multi-walled carbon nanotube/hydroxyapatite nanocomposite film dip coated on Ti–6Al–4V by sol–gel method for biomedical applications: An in vitro study

    Energy Technology Data Exchange (ETDEWEB)

    Abrishamchian, Alireza [Department of Dental Biomaterials, School of Dentistry/Research Center for Science and Technology in Medicine, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Hooshmand, Tabassom, E-mail: hoshmand@sina.tums.ac.ir [Department of Dental Biomaterials, School of Dentistry/Research Center for Science and Technology in Medicine, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Mohammadi, Mohammadreza [Department of Materials Science and Engineering, Sharif University of Technology, Tehran (Iran, Islamic Republic of); Najafi, Farhood [Department of Resin and Additives, Institute for Color Science and Technology, Tehran (Iran, Islamic Republic of)

    2013-05-01

    In the present research, the introduction of multi-walled carbon nanotubes (MWCNTs) into the hydroxyapatite (HA) matrix and dip coating of nanocomposite on titanium alloy (Ti–6Al–4V) plate was conducted in order to improve the performance of the HA-coated implant via the sol–gel method. The structural characterization and electron microscopy results confirmed well crystallized HA–MWCNT coating and homogenous dispersion of carbon nanotubes in the ceramic matrix at temperatures as low as 500 °C. The evaluation of the mechanical properties of HA and HA/MWCNT composite coatings with different weight percentages of MWCNTs showed that the addition of low concentrations of MWCNTs (0.5 and 1 wt.%) had improved effect on the mechanical properties of nanocomposite coatings. Moreover, this in vitro study ascertained the biocompatibility of the prepared sol–gel-derived HA/MWCNT composite coatings. - Highlights: ► Carbon nanotube/hydroxyapatite composite was successfully dip-coated on Ti by sol–gel. ► Well-crystallized HA–MWCNT and homogenous dispersion of nanotubes were obtained. ► Low concentration of CNTs improved the mechanical properties of composite coating. ► Biocompatibility of the prepared sol–gel-derived HA/MWCNT films was ascertained.

  7. Gas diffusion layers coated with a microporous layer containing hydrophilic carbon nanotubes for performance enhancement of polymer electrolyte fuel cells under both low and high humidity conditions

    Science.gov (United States)

    Kitahara, Tatsumi; Nakajima, Hironori; Okamura, Kosuke

    2015-06-01

    Gas diffusion layers (GDLs) coated with a hydrophobic microporous layer (MPL) composed of carbon black and polytetrafluoroethylene (PTFE) have been commonly used to improve the water management characteristics of polymer electrolyte fuel cells (PEFCs). However, the hydrophobic MPL coated GDL designed to prevent dehydration of the membrane under low humidity conditions is generally inferior at reducing flooding under high humidity conditions. It is therefore important to develop a robust MPL coated GDL that can enhance the PEFC performance regardless of the humidity conditions. In the present study, a GDL coated with an MPL containing hydrophilic carbon nanotubes (CNTs) was developed. The less hydrophobic pores incorporating CNTs are effective at conserving the membrane humidity under low humidity conditions. The MPL with CNTs is also effective at expelling excess water from the catalyst layer while maintaining oxygen flow pathways from the GDL substrate, allowing the mean flow pore diameter to be decreased to 2 μm without reducing the ability of the MPL to prevent flooding under high humidity conditions. An MPL coated GDL with a CNT content of 4 mass% exhibits significantly higher performance under both low and high humidity conditions than a hydrophobic MPL coated GDL.

  8. Titanium coated with functionalized carbon nanotubes--a promising novel material for biomedical application as an implantable orthopaedic electronic device.

    Science.gov (United States)

    Przekora, Agata; Benko, Aleksandra; Nocun, Marek; Wyrwa, Jan; Blazewicz, Marta; Ginalska, Grazyna

    2014-12-01

    The aim of the study was to fabricate titanium (Ti) material coated with functionalized carbon nanotubes (f-CNTs) that would have potential medical application in orthopaedics as an implantable electronic device. The novel biomedical material (Ti-CNTs-H2O) would possess specific set of properties, such as: electrical conductivity, non-toxicity, and ability to inhibit connective tissue cell growth and proliferation protecting the Ti-CNTs-H2O surface against covering by cells. The novel material was obtained via an electrophoretic deposition of CNTs-H2O on the Ti surface. Then, physicochemical, electrical, and biological properties were evaluated. Electrical property evaluation revealed that a Ti-CNTs-H2O material is highly conductive and X-ray photoelectron spectroscopy analysis demonstrated that there are mainly COOH groups on the Ti-CNTs-H2O surface that are found to inhibit cell growth. Biological properties were assessed using normal human foetal osteoblast cell line (hFOB 1.19). Conducted cytotoxicity tests and live/dead fluorescent staining demonstrated that Ti-CNTs-H2O does not exert toxic effect on hFOB cells. Moreover, fluorescence laser scanning microscope observation demonstrated that Ti-CNTs-H2O surface retards to a great extent cell proliferation. The study resulted in successful fabrication of highly conductive, non-toxic Ti-CNTs-H2O material that possesses ability to inhibit osteoblast proliferation and thus has a great potential as an orthopaedic implantable electronic device. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Multi-walled carbon nanotube-coated cotton fabric for possible ...

    Indian Academy of Sciences (India)

    This is in corroboration with − characteristics, and is attributed to increased loading of MWCNT through hydrogen bonding with glycosidic group present in cotton (cellulose) fibres. The series capacitance of the MWCNT-coated fabric is about 40 F cm-2, which is found to decrease with the increase in frequency, close to ...

  10. Tantalum oxide/carbon nanotubes composite coatings on titanium, and their functionalization with organophosphonic molecular films: a high quality scaffold for hydroxyapatite growth.

    Science.gov (United States)

    Maho, A; Linden, S; Arnould, C; Detriche, S; Delhalle, J; Mekhalif, Z

    2012-04-01

    Nowadays, titanium is a very commonly used biomaterial for the preparation of orthopedic and dental implants. Its excellent mechanical and biochemical bulk properties are nevertheless counterbalanced by its propensity to long term degradation in physiological conditions and its weak osseointegrative capacities. In this context, surface modifications can significantly hinder titanium weaknesses. The approach considered in this work relies on the preparation of thin composite coatings based on tantalum oxide and carbon nanotubes by sol-gel process. Tantalum is particularly interesting for its high biocompatibility and bioactivity, as well as its strong resistance to bio-corrosion. Carbon nanotubes are exploited to reinforce the compactness and homogeneity of the coatings, and can act as a favorable factor to strengthen the interaction with bone components by biomimicry. The composite layers are further modified with specific organophosphonic acid molecular films, able to chemically bind the tantalum oxide surface and improve the hydroxyapatite formation process. The characteristics and the qualities of these hybrid inorganic/organic coatings are evaluated by XPS, SEM, TEM, peeling tests, contact angle measurements, and electrochemical characterizations (free potential, polarization curves). Copyright © 2012 Elsevier Inc. All rights reserved.

  11. 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.

  12. Preparation of Solid Phase Microextraction (SPME) Probes through Polyaniline Multiwalled Carbon Nanotubes (PANI/MWCNTs) Coating for the Extraction of Palmitic Acid and Oleic Acid in Organic Solvents.

    Science.gov (United States)

    Khajeamiri, Alireza

    2012-01-01

    A fiber coating from polyaniline (PANI) was electrochemically prepared and employed for Solid phase micreoextraction (SPME). The PANI film was directly electrodeposited on the platinum wire surface using cyclic voltametry (CV) technique. The same method was applied for the preparation of SPME fiber coated by polyaniline multiwalled carbon nanotubes (PANI/MWCNTs) composite. The concentration of sulfuric acid for electropolymerization was 0.1 M in the presence of 0.045 M aniline in aqueous solution. For the electrodeposition of PANI/MWCNT composite, 4 μg/mL of MWCNTs was dispersed into the solution. Film coating was carried out on the platinum wire by repetitive cycling of potentials between 0 and 1.0 V at the scan rate of 0.05 V/s. The applicability of these coatings were assessed through employing a laboratory-made SPME injecting device and gas chromatography with mass spectrometry (GC-MS) for the extraction of palmitic acid and oleic acid from chloroform. The developed method proved to be simple and easy, offering high reproducibility. Both PANI coated and PANI/CNT coated probes had the ability to concentrate palmitic acid and oleic acid on their coating and produced strong signals in GC-MS chromatograms. In the meantime, PANI/CNT coated SPME probes produced signals which were stronger than those produced by PANI coated SPME probes. The amount of extracted palmitic acid and oleic acid from chloroform by the PANI/MWCNTs coating was about 6 and 12 times higher than the amount extracted by plane PANI SPME fibers respectively. It could be suggested that the composite material with CNTs has both an increased surface area and an elevated absorptive capacity which leads to this overall increase in extracted palmitic acid and oleic acid.

  13. Enhancement of NH3 Gas Sensitivity at Room Temperature by Carbon Nanotube-Based Sensor Coated with Co Nanoparticles

    OpenAIRE

    Lich Quang Nguyen; Pho Quoc Phan; Chien Duc Nguyen; Huyen Ngoc Duong; Lam Huu Nguyen

    2013-01-01

    Multi-walled carbon nanotube (MWCNT) film has been fabricated onto Pt-patterned alumina substrates using the chemical vapor deposition method for NH3 gas sensing applications. The MWCNT-based sensor is sensitive to NH3 gas at room temperature. Nanoclusters of Co catalysts have been sputtered on the surface of the MWCNT film to enhance gas sensitivity with respect to unfunctionalized CNT films. The gas sensitivity of Co-functionalized MWCNT-based gas sensors is thus significantly improved. The...

  14. Synthesis and characterization of polyamidoamine dendrimer-coated multi-walled carbon nanotubes and their application in gene delivery systems

    Energy Technology Data Exchange (ETDEWEB)

    Pan Bifeng; Cui Daxiang; Xu Ping; Feng Gao; Huang Tuo; Li Qing; He Rong [Department of Bio-Nano-Science and Engineering, National Key Laboratory of Nano/Micro Fabrication Technology, Key Laboratory for Thin Film and Microfabrication of Ministry of Education, Institute of Micro-Nano Science and Technology, Shanghai JiaoTong University, 800 Dongchuan Road, Shanghai 200240 (China); Ozkan, Cengiz [Mechanical Engineering Department, University of California Riverside, 900 University Avenue-Riverside, CA 92521 (United States); Ozkan, Mihri [Electrical Engineering Department, University of California Riverside, 900 University Avenue, Riverside, CA 92521 (United States); Chu, Bingfeng [Department of Stomatology, General Hospital of PLA, 28 Fuxing Road, Beijing100853 (China); Hu Guohan [Department of Neurosurgery of Changzheng Hospital, 415 Fengyang Road, Second Military Medical University, Shanghai 20003 (China)], E-mail: dxcui@sjtu.edu.cn, E-mail: huguohan6504@sina.com

    2009-03-25

    With the aim of improving the amount and delivery efficiency of genes taken by carbon nanotubes into human cancer cells, different generations of polyamidoamine dendrimer modified multi-walled carbon nanotubes (dMNTs) were fabricated, and characterized by high-resolution transmission electron microscopy, atomic force microscopy, x-ray photoelectron spectroscopy, Raman spectroscopy, Fourier transform infrared spectroscopy and thermogravimetric analysis, revealing the presence of dendrimer capped on the surface of carbon nanotubes. The dMNTs fully conjugated with FITC-labeled antisense c-myc oligonucleotides (asODN), those resultant asODN-dMNTs composites were incubated with human breast cancer cell line MCF-7 cells and MDA-MB-435 cells, and liver cancer cell line HepG2 cells, and confirmed to enter into tumor cells within 15 min by laser confocal microscopy. These composites inhibited the cell growth in time- and dose-dependent means, and down-regulated the expression of the c-myc gene and C-Myc protein. Compared with the composites of CNT-NH{sub 2}-asODN and dendrimer-asODN, no. 5 generation of dendrimer-modified MNT-asODN composites exhibit maximal transfection efficiencies and inhibition effects on tumor cells. The intracellular gene transport and uptake via dMNTs should be generic for the mammalian cell lines. The dMNTs have potentials in applications such as gene or drug delivery for cancer therapy and molecular imaging.

  15. Coating of carbon nanotube fibers: variation of tensile properties, failure behavior and adhesion strength

    Science.gov (United States)

    Mäder, Edith; Liu, Jian-Wen; Hiller, Janett; Lu, Weibang; Li, Qingwen; Zhandarov, Serge; Chou, Tsu-Wei

    2015-07-01

    An experimental study of the tensile properties of CNT fibers and their interphasial behavior in epoxy matrices is reported. One of the most promising applications of CNT fibers is their use as reinforcement in multifunctional composites. For this purpose, an increase of the tensile strength of the CNT fibers in unidirectional composites as well as strong interfacial adhesion strength is desirable. However, the mechanical performance of the CNT fiber composites manufactured so far is comparable to that of commercial fiber composites. The interfacial properties of CNT fiber/polymer composites have rarely been investigated and provided CNT fiber/epoxy interfacial shear strength of 14.4 MPa studied by the microbond test. In order to improve the mechanical performance of the CNT fibers, an epoxy compatible coating with nano-dispersed aqueous based polymeric film formers and low viscous epoxy resin, respectively, was applied. For impregnation of high homogeneity, low molecular weight epoxy film formers and polyurethane film formers were used. The aqueous based epoxy film formers were not crosslinked and able to interdiffuse with the matrix resin after impregnation. Due to good wetting of the individual CNT fibers by the film formers, the degree of activation of the fibers was improved leading to increased tensile strength and Young’s modulus. Cyclic tensile loading and simultaneous determination of electric resistance enabled to characterize the fiber’s durability in terms of elastic recovery and hysteresis. The pull-out tests and SEM study reveal different interfacial failure mechanisms in CNT fiber/epoxy systems for untreated and film former treated fibers, on the one hand, and epoxy resin treated ones, on the other hand. The epoxy resin penetrated between the CNT bundles in the reference or film former coated fiber, forming a relatively thick CNT/epoxy composite layer and thus shifting the fracture zone within the fiber. In contrast to this, shear sliding along

  16. Coating of carbon nanotube fibers: variation of tensile properties, failure behavior and adhesion strength

    Directory of Open Access Journals (Sweden)

    Edith eMäder

    2015-07-01

    Full Text Available An experimental study of the tensile properties of CNT fibers and their interphasial behavior in epoxy matrices is reported. One of the most promising applications of CNT fibers is their use as reinforcement in multifunctional composites. For this purpose, an increase of the tensile strength of the CNT fibers in unidirectional composites as well as strong interfacial adhesion strength is desirable. However, the mechanical performance of the CNT fiber composites manufactured so far is comparable to that of commercial fiber composites. The interfacial properties of CNT fiber/polymer composites have rarely been investigated and provided CNT fiber/epoxy interfacial shear strength of 14.4 MPa studied by the microbond test.In order to improve the mechanical performance of the CNT fibers, an epoxy compatible coating with nano-dispersed aqueous based polymeric film formers and low viscous epoxy resin, respectively, was applied. For impregnation of high homogeneity, low molecular weight epoxy film formers and polyurethane film formers were used. The aqueous based epoxy film formers were not crosslinked and able to interdiffuse with the matrix resin after impregnation. Due to good wetting of the individual CNT fibers by the film formers, the degree of activation of the fibers was improved leading to increased tensile strength and Young’s modulus. Cyclic tensile loading and simultaneous determination of electric resistance enabled to characterize the fiber’s durability in terms of elastic recovery and hysteresis.The pull-out tests and SEM study reveal different interfacial failure mechanisms in CNT fiber/epoxy systems for untreated and film former treated fibers, on the one hand, and epoxy resin treated ones, on the other hand. The epoxy resin penetrated between the CNT bundles in the reference or film former coated fiber, forming a relatively thick CNT/epoxy composite layer and thus shifting the fracture zone within the fiber. In contrast to this

  17. Carbon Nanotubes for Supercapacitor

    OpenAIRE

    Li Jianyi; Pan Hui; Feng YuanPing

    2010-01-01

    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 disad...

  18. 148. Carbon Nanotubes

    OpenAIRE

    Hedmer, Maria; Kåredal, Monica; Gustavsson, Per; Rissler, Jenny

    2013-01-01

    Carbon nanotubes (CNTs) can be seen as graphene sheets rolled to form cylinders. CNTs may be categorised as single- (SWCNT) or multi-walled (MWCNT). Due to the small size, the number of particles as well as the surface area per mass unit is extremely high. CNTs are highly diverse, differing with respect to e.g., diameter, length, chiral angles, chemical functionalisation, purity, stiffness and bulk density. Today, CNTs are utilised primarily for the reinforcement of composite polymers, but th...

  19. Carbon nanotube IR detectors (SV)

    Energy Technology Data Exchange (ETDEWEB)

    Leonard, F. L.

    2012-03-01

    Sandia National Laboratories (Sandia) and Lockheed Martin Corporation (LMC) collaborated to (1) evaluate the potential of carbon nanotubes as channels in infrared (IR) photodetectors; (2) assemble and characterize carbon nanotube electronic devices and measure the photocurrent generated when exposed to infrared light;(3) compare the performance of the carbon nanotube devices with that of traditional devices; and (4) develop and numerically implement models of electronic transport and opto-electronic behavior of carbon nanotube infrared detectors. This work established a new paradigm for photodetectors.

  20. Noncovalently silylated carbon nanotubes decorated with quantum dots

    OpenAIRE

    Bottini, Massimo; Magrini, Andrea; Dawson, Marcia I.; Rosato, Nicola; Bergamaschi, Antonio; Mustelin, Tomas

    2007-01-01

    A nanoassembly of single-walled carbon nanotubes coated by a thin layer of silica followed by quantum dots was prepared. That the quantum dots retained their photoluminescent properties after deposition onto the silylated carbon nanotubes suggests that the thin layer of silica prevented the quenching of the fluorescence by the nanotubes. This fluorescent nanoassembly represents an excellent building block for photoelectric and optical devices and biological nanoprobes.

  1. Preparing hydroxyapatite-silicon composite suspensions with homogeneous distribution of multi-walled carbon nano-tubes for electrophoretic coating of NiTi bone implant and their effect on the surface morphology

    Energy Technology Data Exchange (ETDEWEB)

    Khalili, Vida [Research Center for Advanced Materials and Mineral Processing, Faculty of Materials Engineering, Sahand University of Technology, Tabriz (Iran, Islamic Republic of); Department of Mechanical Engineering, University of Bonab, P.O.Box: 5551761167, Bonab (Iran, Islamic Republic of); Khalil-Allafi, Jafar, E-mail: allafi@sut.ac.ir [Research Center for Advanced Materials and Mineral Processing, Faculty of Materials Engineering, Sahand University of Technology, Tabriz (Iran, Islamic Republic of); Xia, Wei [Institute for Industrial Chemistry, Ruhr-University Bochum, Bochum, 44780 Germany (Germany); Parsa, Alireza B.; Frenzel, Jan; Somsen, Christoph; Eggeler, Gunther [Institute for Materials, Faculty of Mechanical Engineering, Ruhr-University Bochum Bochum, 44801 (Germany)

    2016-03-15

    Graphical abstract: - Highlights: • The stable composite suspensions of hydroxyapatite, silicon and multi-walled carbon nano-tubes was prepared using functionalization of and multi-walled carbon nano-tubes in HNO{sub 3} vapor and triethanolamine as dispersing agent. • The zeta potential of composite suspensions is less than that of hydroxyapatite suspension. • The silicon particles presence in suspension causes to decrease the charge carrier in suspension and current density during electrophoretic deposition. • The orientation of multi-walled carbon nano-tubes to parallel direction of the applied electric field during electrophoretic deposition can facilitate their moving towards the cathode and increase current density. • The more zeta potential of suspension, the lower roughness of coatings during electrophoretic deposition. - Abstract: Preparing a stable suspension is a main step towards the electrophoretically depositing of homogeneous and dense composite coatings on NiTi for its biomedical application. In the present study, different composite suspensions of hydroxyapatite, silicon and multi-walled carbon nano-tubes were prepared using n-butanol and triethanolamine as media and dispersing agent, respectively. Multi-walled carbon nanotubes were first functionalized in the nitric acid vapor for 15 h at 175 °C, and then mixed into suspensions. Thermal desorption spectroscopy profiles indicate the formation of functional groups on multi-walled carbon nano-tubes. An excellent suspension stability can be achieved for different amounts of triethanolamine. The amount of triethanolamine can be increased by adding a second component to a stable hydroxyapatite suspension due to an electrostatic interaction between components in suspension. The stability of composite suspension is less than that of the hydroxyapatite suspension, due to density differences, which under the gravitational force promote the demixing. The scanning electron microscopy images of the

  2. RGD-conjugated silica-coated gold nanorods on the surface of carbon nanotubes for targeted photoacoustic imaging of gastric cancer

    Science.gov (United States)

    Wang, Can; Bao, Chenchen; Liang, Shujing; Fu, Hualin; Wang, Kan; Deng, Min; Liao, Qiande; Cui, Daxiang

    2014-05-01

    Herein, we reported for the first time that RGD-conjugated silica-coated gold nanorods on the surface of multiwalled carbon nanotubes were successfully used for targeted photoacoustic imaging of in vivo gastric cancer cells. A simple strategy was used to attach covalently silica-coated gold nanorods (sGNRs) onto the surface of multiwalled carbon nanotubes (MWNTs) to fabricate a hybrid nanostructure. The cross-linked reaction occurred through the combination of carboxyl groups on the MWNTs and the amino group on the surface of sGNRs modified with a silane coupling agent. RGD peptides were conjugated with the sGNR/MWNT nanostructure; resultant RGD-conjugated sGNR/MWNT probes were investigated for their influences on viability of MGC803 and GES-1 cells. The nude mice models loaded with gastric cancer cells were prepared, the RGD-conjugated sGNR/MWNT probes were injected into gastric cancer-bearing nude mice models via the tail vein, and the nude mice were observed by an optoacoustic imaging system. Results showed that RGD-conjugated sGNR/MWNT probes showed good water solubility and low cellular toxicity, could target in vivo gastric cancer cells, and obtained strong photoacoustic imaging in the nude model. RGD-conjugated sGNR/MWNT probes will own great potential in applications such as targeted photoacoustic imaging and photothermal therapy in the near future.

  3. Anticorrosion Coating of Carbon Nanotube/Polytetrafluoroethylene Composite Film on the Stainless Steel Bipolar Plate for Proton Exchange Membrane Fuel Cells

    Directory of Open Access Journals (Sweden)

    Yoshiyuki Show

    2013-01-01

    Full Text Available Composite film of carbon nanotube (CNT and polytetrafluoroethylene (PTFE was formed from dispersion fluids of CNT and PTFE. The composite film showed high electrical conductivity in the range of 0.1–13 S/cm and hydrophobic nature. This composite film was applied to stainless steel (SS bipolar plates of the proton exchange membrane fuel cell (PEMFC as anticorrosion film. This coating decreased the contact resistance between the surface of the bipolar plate and the membrane electrode assembly (MEA of the PEMFC. The output power of the fuel cell is increased by 1.6 times because the decrease in the contact resistance decreases the series resistance of the PEMFC. Moreover, the coating of this composite film protects the bipolar plate from the surface corrosion.

  4. The controlled deposition of metal oxides onto carbon nanotubes by atomic layer deposition: examples and a case study on the application of V2O4 coated nanotubes in gas sensing.

    Science.gov (United States)

    Willinger, Marc-Georg; Neri, Giovanni; Bonavita, Anna; Micali, Giuseppe; Rauwel, Erwan; Herntrich, Tobias; Pinna, Nicola

    2009-05-21

    A new atomic layer deposition (ALD) process was applied for the uniform coating of carbon nanotubes with a number of transition-metal oxide thin films (vanadium, titanium, and hafnium oxide). The presented approach is adapted from non-aqueous sol-gel chemistry and utilizes metal alkoxides and carboxylic acids as precursors. It allows the coating of the inner and outer surface of the tubes with a highly conformal film of controllable thickness and hence, the production of high surface area hybrid materials. The morphology and the chemical composition as well as the high purity of the films are evidenced through a combination of electron microscopic and electron-energy-loss spectrometric techniques. Furthermore, in order to highlight a possible application of the obtained hybrids, the electrical and sensing properties of resistive gas sensors based on hybrid vanadium oxide-coated carbon nanotubes (V2O4-CNTs) are reported and the effect of thermal treatment on the gas sensing properties is studied.

  5. A simple preparation of very high methanol tolerant cathode electrocatalyst for direct methanol fuel cell based on polymer-coated carbon nanotube/platinum.

    Science.gov (United States)

    Yang, Zehui; Nakashima, Naotoshi

    2015-07-20

    The development of a durable and methanol tolerant electrocatalyst with a high oxygen reduction reaction activity is highly important for the cathode side of direct methanol fuel cells. Here, we describe a simple and novel methodology to fabricate a practically applicable electrocatalyst with a high methanol tolerance based on poly[2,2'-(2,6-pyridine)-5,5'-bibenzimidazole]-wrapped multi-walled carbon nanotubes, on which Pt nanoparticles have been deposited, then coated with poly(vinylphosphonic acid) (PVPA). The polymer coated electrocatalyst showed an ~3.3 times higher oxygen reduction reaction activity compared to that of the commercial CB/Pt and methanol tolerance in the presence of methanol to the electrolyte due to a 50% decreased methanol adsorption on the Pt after coating with the PVPA. Meanwhile, the peroxide generation of the PVPA coated electrocatalyst was as low as 0.8% with 2 M methanol added to the electrolyte, which was much lower than those of the non-PVPA-coated electrocatalyst (7.5%) and conventional CB/Pt (20.5%). Such a high methanol tolerance is very important for the design of a direct methanol fuel cell cathode electrocatalyst with a high performance.

  6. Electrically conductive poly-ɛ-caprolactone/polyethylene glycol/multi-wall carbon nanotube nanocomposite scaffolds coated with fibrin glue for myocardial tissue engineering

    Science.gov (United States)

    Mehdikhani, Mehdi; Ghaziof, Sharareh

    2018-01-01

    In this research, poly-ɛ-caprolactone (PCL), polyethylene glycol (PEG), multi-wall carbon nanotubes (MWCNTs), and nanocomposite scaffolds containing 0.5 and 1% (w/w) MWCNTs coated with fibrin glue (FG) were prepared via solvent casting and freeze-drying technique for cardiac tissue engineering. Scanning electron microscopy, transmission electron microscopy, Fourier transform-infrared spectroscopy, and X-ray diffraction were used to characterize the samples. Furthermore, mechanical properties, electrical conductivity, degradation, contact angle, and cytotoxicity of the samples were evaluated. Results showed the uniform distribution of the MWCNTs with some aggregates in the prepared nanocomposite scaffolds. The scaffolds containing 1% (w/w) MWCNTs with and without FG coating illustrated optimum modulus of elasticity, high electrical conductivity, and wettability compared with PCL/PEG and PCL/PEG/0.5%(w/w) MWCNTs' scaffolds. FG coating enhanced electrical conductivity and cell response, and increased wettability of the constructs. The prepared scaffolds were degraded significantly after 60 days of immersion in PBS. Meanwhile, the nanocomposite containing 1% (w/w) MWCNTs with FG coating (S3) showed proper spreading and viability of the myoblasts seeded on it after 1, 4, and 7 days of culture. The scaffold containing 1% (w/w) MWCNTs with FG coating demonstrated optimal properties including acceptable mechanical properties, proper wettability, high electrical conductivity, satisfactory degradation, and excellent myoblasts response to it.

  7. Black silicon maskless templates for carbon nanotube forests

    DEFF Research Database (Denmark)

    Wierzbicki, Rafal; Schmidt, Michael Stenbæk; Boisen, Anja

    2013-01-01

    We present here a proof of concept for a novel fabrication method of vertically aligned carbon nanotube forests, utilizing black silicon nanograss (a forest of silicon nanometer-sized spikes created with reactive ion etching) coated with titanium tungsten diffusion barrier as a template. The method...... allows maskless definition of carbon nanotube forests with control of their density, nanotube diameter and height. Four nanograss reactive ion etching recipes are investigated and their wafer-to-wafer repeatability, wafer uniformity, and density control is discussed. Evaluation of carbon nanotube forests...

  8. Enhancement of NH3 Gas Sensitivity at Room Temperature by Carbon Nanotube-Based Sensor Coated with Co Nanoparticles

    Directory of Open Access Journals (Sweden)

    Lich Quang Nguyen

    2013-01-01

    Full Text Available Multi-walled carbon nanotube (MWCNT film has been fabricated onto Pt-patterned alumina substrates using the chemical vapor deposition method for NH3 gas sensing applications. The MWCNT-based sensor is sensitive to NH3 gas at room temperature. Nanoclusters of Co catalysts have been sputtered on the surface of the MWCNT film to enhance gas sensitivity with respect to unfunctionalized CNT films. The gas sensitivity of Co-functionalized MWCNT-based gas sensors is thus significantly improved. The sensor exhibits good repeatability and high selectivity towards NH3, compared with alcohol and LPG.

  9. Enhancement of NH3 gas sensitivity at room temperature by carbon nanotube-based sensor coated with Co nanoparticles.

    Science.gov (United States)

    Nguyen, Lich Quang; Phan, Pho Quoc; Duong, Huyen Ngoc; Nguyen, Chien Duc; Nguyen, Lam Huu

    2013-01-30

    Multi-walled carbon nanotube (MWCNT) film has been fabricated onto Pt-patterned alumina substrates using the chemical vapor deposition method for NH(3) gas sensing applications. The MWCNT-based sensor is sensitive to NH(3) gas at room temperature. Nanoclusters of Co catalysts have been sputtered on the surface of the MWCNT film to enhance gas sensitivity with respect to unfunctionalized CNT films. The gas sensitivity of Co-functionalized MWCNT-based gas sensors is thus significantly improved. The sensor exhibits good repeatability and high selectivity towards NH(3), compared with alcohol and LPG.

  10. Electrochemical Detection of Anti-Breast-Cancer Agents in Human Serum by Cytochrome P450-Coated Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Camilla Baj-Rossi

    2012-05-01

    Full Text Available We report on the electrochemical detection of anti-cancer drugs in human serum with sensitivity values in the range of 8–925 nA/µM. Multi-walled carbon nanotubes were functionalized with three different cytochrome P450 isoforms (CYP1A2, CYP2B6, and CYP3A4. A model used to effectively describe the cytochrome P450 deposition onto carbon nanotubes was confirmed by Monte Carlo simulations. Voltammetric measurements were performed in phosphate buffer saline (PBS as well as in human serum, giving well-defined current responses upon addition of increasing concentrations of anti-cancer drugs. The results assert the capability to measure concentration of drugs in the pharmacological ranges in human serum. Another important result is the possibility to detect pairs of drugs present in the same sample, which is highly required in case of therapies with high side-effects risk and in anti-cancer pharmacological treatments based on mixtures of different drugs. Our technology holds potentials for inexpensive multi-panel drug-monitoring in personalized therapy.

  11. Electron configuration of carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Stojkovic, S.M.; Setrajcic, J.P. [Novi Sad Univ. (Yugoslavia). Inst. of Physics; Vragovic, I.D. [Technical Faculty M. Pupin, Zrenjanin (Yugoslavia)

    2000-07-01

    In the paper the analysis of electron band structure of infinite carbon nanotubes was performed using Green's function method. The electron dispersion law was found in harmonic and nearest neighbor approximation. One can see that carbon nanotubes of infinite length can be divided into two classes: metallic and semiconducting. Additional spatial confinement of the system along the nanotube axes leads to the opening of the forbidden gap even in nanotubes that are metallic for infinite length. The value of the forbidden gap decreases by increasing the tube length. The dependence of the forbidden gap on the tube length is not monotonic; it has oscillatory character for short tubes. (orig.)

  12. 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.

  13. Titania carbon nanotube composites for enhanced photocatalysis

    Science.gov (United States)

    Pyrgiotakis, Georgios

    Photocatalytic composites have been used for the past few decades in a wide range of applications. The most common application is the purification of air and water by removing toxic compounds. There is limited use however towards biocidal applications. Despite their high efficiency, photocatalytic materials are not comparable to the effectiveness of conventional biocidal compounds such as chlorine and alcoholic disinfectants. On the other hand, nearly a decade ago with the discovery of the carbon nanotubes a new vibrant scientific field emerged. Nanotubes are unique structures of carbon that posse amazing electrical, mechanical and thermal properties. In this research carbon nanotubes are used as photocatalytic enhancers. They were coated with anatase titania to form a composite material. Two different types of nanotubes (metallic versus non-metallic) were used and the photocatalytic activity was measured. The metallic tubes demonstrated exceptional photocatalytic properties, while non-metallic tubes had low photocatalytic efficiency. The reason for that difference was investigated and was the major focus of this research. The research concluded that the reasons for the high efficiency of the carbon nanotubes were (i) the metallic nature of the tubes and (ii) the possible bond between the titania coating and the underlying graphite layers (C-O-Ti). Since both composites had the same indications regarding the C-O-Ti bond, the metallic nature of the carbon nanotubes is believed to be the most dominant factor contributing to the enhancement of the photocatalysis. The composite material may have other potential applications such as for sensing and photovoltaic uses.

  14. Effect of dentin surface modification using carbon nanotubes on dental bonding and antibacterial ability.

    Science.gov (United States)

    Suo, Lai; Li, Zhongjie; Luo, Feng; Chen, Junyu; Jia, Lingling; Wang, Tong; Pei, Xibo; Wan, Qianbing

    2017-11-03

    This study developed carbon nanotube coatings for the dentin surface and investigated the bonding strength and the in vitro antibacterial properties of carbon nanotube-coated dentin. Single-walled carbon nanotubes and multi-walled carbon nanotubes were first modified and then characterized using Fourier-transform infrared spectroscopy, scanning electron microscope, and transmission electron microscopy. Second, dentin samples were coated using either single-walled carbon nanotubes or multi-walled carbon nanotubes and observed under a scanning electron microscope. Then, the shear bonding strength and antibacterial properties of the dentin samples were tested. The results showed that both modified single-walled carbon nanotubes and multi-walled carbon nanotubes formed a stable coating on the dentin surface without affecting the shear bonding strength. Moreover, the antibacterial properties of the single-walled carbon nanotube-coated samples was obviously superior to those of the multi-walled carbon nanotubecoated samples. Consequently, single-walled carbon nanotube coating may be an antibacterial agent for potential application in the dental bonding field.

  15. Highly Stretchable Conductive Fibers from Few-Walled Carbon Nanotubes Coated on Poly(m-phenylene isophthalamide) Polymer Core/Shell Structures.

    Science.gov (United States)

    Jiang, Shujuan; Zhang, Hongbo; Song, Shaoqing; Ma, Yanwen; Li, Jinghua; Lee, Gyeong Hee; Han, Qiwei; Liu, Jie

    2015-10-27

    A core/shell stretchable conductive composite of a few-walled carbon nanotube network coated on a poly(m-phenylene isophthalamide) fiber (FWNT/PMIA) was fabricated by a dip-coating method and an annealing process that greatly enhanced interactions between the FWNT network and PMIA core as well as within the FWNT network. The first strain-conductivity test of the as-prepared FWNT/PMIA fiber showed a stretching-induced alignment of nanotubes in the shell during the deformation process and a good conductivity stability with a slight conductivity drop from 109.63 S/cm to 98.74 S/cm (Δσ/σ0 = 10%) at a strain of ∼150% (2.5 times the original length). More importantly, after the first stretching process, the fiber can be recovered with a slight increase in length but a greatly improved conductivity of 167.41 S/cm through an additional annealing treatment. The recovered fiber displays a similarly superb conductivity stability against stretching, with a decrease of only ∼13 S/cm to 154.49 S/cm (Δσ/σ0 = 8%) at a strain of ∼150%. We believe that this conductivity stability came from the formation and maintaining of aligned nanotube structures during the stretching process, which ensures the good tube-tube contacts and the elongation of the FWNT network without losing its conductivity. Such stable conductivity in stretchable fibers will be important for applications in stretchable electronics.

  16. Advanced carbon nanotubes functionalization

    Science.gov (United States)

    Setaro, A.

    2017-10-01

    Similar to graphene, carbon nanotubes are materials made of pure carbon in its sp2 form. Their extended conjugated π-network provides them with remarkable quantum optoelectronic properties. Frustratingly, it also brings drawbacks. The π-π stacking interaction makes as-produced tubes bundle together, blurring all their quantum properties. Functionalization aims at modifying and protecting the tubes while hindering π-π stacking. Several functionalization strategies have been developed to circumvent this limitation in order for nanotubes applications to thrive. In this review, we summarize the different approaches established so far, emphasizing the balance between functionalization efficacy and the preservation of the tubes’ properties. Much attention will be given to a functionalization strategy overcoming the covalent-noncovalent dichotomy and to the implementation of two advanced functionalization schemes: (a) conjugation with molecular switches, to yield hybrid nanosystems with chemo-physical properties that can be tuned in a controlled and reversible way, and; (b) plasmonic nanosystems, whose ability to concentrate and enhance the electromagnetic fields can be taken advantage of to enhance the optical response of the tubes.

  17. 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

  18. Carbon Nanotube Biosensors

    Science.gov (United States)

    Tilmaciu, Carmen-Mihaela; Morris, May

    2015-10-01

    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 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.

  19. 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.

  20. 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.

  1. 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. Copyright © 2011 Elsevier Inc. All rights reserved.

  2. Improving the Sound Pressure Level of Two-Dimensional Audio Actuators by Coating Single-Walled Carbon Nanotubes on Piezoelectric Films.

    Science.gov (United States)

    Um, Keehong

    2015-10-01

    As devices for amplifying or transforming electronic signals into audible signals through electromechanical operations, acoustic actuators in the form of loudspeakers are usually solid structures in three dimensional space. Recently there has been increasing demand for mobile electronic devices, such as mobile phones, to become smaller, thinner, and lighter. In contrast to a three dimensional audio system with magnets, we have invented a new type of flexible two dimensional device by utilizing the reverse piezoelectric effect in certain piezoelectric materials. Crystalline piezoelectric materials show electromechanical interaction between the mechanical state and the electrically-charged state. The piezoelectric effect is a reversible process in that materials exhibiting the direct piezoelectric effect (the internal generation of electrical charge resulting from an applied mechanical force) also exhibit the reverse piezoelectric effect (the internal generation of a mechanical strain resulting from an applied electrical field). We have adopted the plasma surface treatment in order to put coating materials on the surface of piezoelectric film. We compared two kinds of coating material, indium tin oxide and single-walled carbon nanotube, and found that single-walled carbon nanotube shows better performance. The results showed improvement of output power in a wider range of operating frequency; for the surface resistance of 0.5 kΩ/square, the single-walled CNT shows the range of operating frequency to be 0.75-17.5 kHz, but ITO shows 2.5-13.4 kHz. For the surface resistance of 1 kΩ/square, single-walled CNT shows the range of operating frequency to be 0.81-17 kHz, but ITO shows it cannot generate audible sound.

  3. Construction of a new selective coated disk electrode for Ag (I) based on modified polypyrrole-carbon nanotubes composite with new lariat ether.

    Science.gov (United States)

    Abbaspour, A; Tashkhourian, J; Ahmadpour, S; Mirahmadi, E; Sharghi, H; Khalifeh, R; Shahriyari, M R

    2014-01-01

    A poly (vinyl chloride) (PVC) matrix membrane ion-selective electrode for silver (I) ion is fabricated based on modified polypyrrole - multiwalled carbon nanotubes composite with new lariat ether. This sensor has a Nernstian slope of 59.4±0.5mV/decade over a wide linear concentration range of 1.0×10(-7) to 1.0×10(-1)molL(-1) for silver (I) ion. It has a short response time of about 8.0s and can be used for at least 50days. The detection limit is 9.3×10(-8)molL(-1) for silver (I) ion, and the electrode was applicable in the wide pH range of 1.6 -7.7. The electrode shows good selectivity for silver ion against many cations such as Hg (II), which usually imposes serious interference in the determination of silver ion concentration. The use of multiwalled carbon nanotubes (MWCNTs) in a polymer matrix improves the linear range and sensitivity of the electrode. In addition by coating the solid contact with a layer of the polypyrrole (Ppy) before coating the membrane on it, not only did it reduce the drift in potential, but a shorter response time was also resulted. The proposed electrode was used as an indicator electrode for potentiometric titration of silver ions with chloride anions and in the titration of mixed halides. This electrode was successfully applied for the determination of silver ions in silver sulphadiazine as a burning cream. © 2013.

  4. Single carbon nanotube photovoltaic device

    NARCIS (Netherlands)

    Barkelid, K.M.; Zwiller, V.G.

    2013-01-01

    Here we present photocurrent measurements on a single suspended carbon nanotube p-n junction. The p-n junction was induced by electrostatic doping by local gates, and the E11 and E22 resonances in the nanotube could be probed using photocurrent spectroscopy. Current-voltage characteristics were

  5. Ultra strong silicon-coated carbon nanotube nonwoven fabric as a multifunctional lithium-ion battery anode.

    Science.gov (United States)

    Evanoff, Kara; Benson, Jim; Schauer, Mark; Kovalenko, Igor; Lashmore, David; Ready, W Jud; Yushin, Gleb

    2012-11-27

    Materials that can perform simultaneous functions allow for reductions in the total system mass and volume. Developing technologies to produce flexible batteries with good performance in combination with high specific strength is strongly desired for weight- and power-sensitive applications such as unmanned or aerospace vehicles, high-performance ground vehicles, robotics, and smart textiles. State of the art battery electrode fabrication techniques are not conducive to the development of multifunctional materials due to their inherently low strength and conductivities. Here, we present a scalable method utilizing carbon nanotube (CNT) nonwoven fabric-based technology to develop flexible, electrochemically stable (∼494 mAh·g(-1) for 150 cycles) battery anodes that can be produced on an industrial scale and demonstrate specific strength higher than that of titanium, copper, and even a structural steel. Similar methods can be utilized for the formation of various cathode and anode composites with tunable strength and energy and power densities.

  6. N-Epoxypropyl poly(p-phenylene terephthalamide) covalently and non-covalently coated multi-walled carbon nanotubes for PVC reinforcement

    Science.gov (United States)

    Pan, Fangwei; Qu, Rongjun; Jia, Xinhua; Sun, Changmei; Sun, Hushan; An, Kai; Mu, Yinglei; Ji, Chunnuan; Yin, Ping; Zhang, Ying

    2017-09-01

    Poly(p-phenylene terephthalamide) (PPTA) coated multi-walled carbon nanotubes (PPTA-MWNTs) showed an enhancement effect on the yield strength and Young's modulus of PVC composite films, but no improvement in toughness. In this paper, MWNTs were covalently and non-covalently coated by N-epoxypropyl PPTA (PPTA-ECH) to prepare PPTA-ECH-MWNTs-NH2-x and PPTA-ECH-MWNTs-x, which were used as additives to reinforce PVC composite films. It was found that the maximum yield strength, Young's modulus, and toughness of PPTA-ECH-MWNTs-NH2-x/PVC composite films increased by 227.84%, 201.56%, and 589.96%, respectively, in comparison to pure PVC, while those of PPTA-ECH-MWNTs-x/PVC composite films increased by 215.08%, 153.13%, and 540.81%, respectively. The maximum yield strength, maximum Young's modulus, and maximum toughness of both PPTA-ECH-MWNTs-NH2-x/PVC and PPTA-ECH-MWNTs-x/PVC showed significant improvement as compared to PPTA-MWNTs/PVC composite film and PPTA-MWNTs-NH2/PVC. This indicates that N-epoxypropyl PPTA covalently and non-covalently coated MWNTs are promising additives for reinforcing PVC.

  7. Characteristics of Carbon Nanotubes/Graphene Coatings on Stainless Steel Meshes Used as Electrodes for Air-Cathode Microbial Fuel Cells

    Directory of Open Access Journals (Sweden)

    Wei-Hsuan Hsu

    2017-01-01

    Full Text Available Microbial fuel cells (MFCs generate low-pollution power by feeding organic matter to bacteria; MFC applications have become crucial for energy recovery and environmental protection. The electrode materials of any MFC affect its power generation capacity. In this research, nine single-chamber MFCs with various electrode configurations were investigated and compared with each other. A fabrication process for carbon-based electrode coatings was proposed, and Escherichia coli HB101 was used in the studied MFC system. The results show that applying a coat of either graphene or carbon nanotubes (CNTs to a stainless steel mesh electrode can improve the power density and reduce the internal resistance of an MFC system. Using the proposed surface modification method, CNTs and graphene used for anodic and cathodic modification can increase power generation by approximately 3–7 and 1.5–4.5 times, respectively. Remarkably, compared to a standard MFC with an untreated anode, the internal resistances of MFCs with CNTs- and graphene-modified anodes were reduced to 18 and 30% of standard internal resistance. Measurements of the nine systems we studied clearly presented the performance levels of CNTs and graphene applied as surface modification of stainless steel mesh electrodes.

  8. 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.

  9. Transparent, Conductive Carbon Nanotube Films

    National Research Council Canada - National Science Library

    Zhuangchun Wu; Zhihong Chen; Xu Du; Jonathan M. Logan; Jennifer Sippel; Maria Nikolou; Katalin Kamaras; John R. Reynolds; David B. Tanner; Arthur F. Hebard; Andrew G. Rinzler

    2004-01-01

    We describe a simple process for the fabrication of ultrathin, transparent, optically homogeneous, electrically conducting films of pure single-walled carbon nanotubes and the transfer of those films...

  10. 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.

  11. Carbon Nanotubes and Related Structures

    OpenAIRE

    Kingsuk Mukhopadhyay; Kanik Ram; K.U. Bhasker Rao

    2008-01-01

    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 a...

  12. 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....

  13. 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.

  14. Synthesis and application of ion imprinting polymer coated magnetic multi-walled carbon nanotubes for selective adsorption of nickel ion

    Science.gov (United States)

    He, Junnan; Shang, Hongzhou; Zhang, Xing; Sun, Xiaoran

    2018-01-01

    A novel nickel ion imprinted polymers (IIPs) based on multi-walled carbon nanotubes (MWCNTs) were synthesized inverse emulsion system, using chitosan(CS) and acrylic acid as the functional monomers, Ni (II) as the template, and N' N-methylene bis-acrylamide as the cross-linker. The chemical structure and morphological feature of the IIPs were characterized by scanning electron microscopy (SEM), Thermogravimetry (TG), X-ray diffraction (XRD), and Fourier transform infrared spectrometer (FTIR). The studies indicated that the gel layer was well grafted on the surface of MWCNTs. Studies on the adsorption ability of the IIPs, by atomic absorption spectrophotometry, demonstrated that IIPs possessed excellent adsorption and selective ability towards Ni (II), fitting to pseudo second-order kinetic isotherms and with a maximum capacity of 19.86 mg/g, and selectivity factor of 13.09 and 4.42. The electrochemical performance of ion imprinting carbon paste electrode (CPE/IIPs) was characterized by Cyclic voltammetry (CV). Studies have shown that CPE/IIPs showed excellent electrochemical performance.

  15. Highly sensitive and selective sensor for sunset yellow based on molecularly imprinted polydopamine-coated multi-walled carbon nanotubes.

    Science.gov (United States)

    Yin, Zheng-Zhi; Cheng, Shu-Wen; Xu, Li-Bin; Liu, Hong-Ying; Huang, Kai; Li, Lei; Zhai, Yun-Yun; Zeng, Yan-Bo; Liu, Hai-Qing; Shao, Yong; Zhang, Zu-Lei; Lu, Yi-Xia

    2018-02-15

    Polydopamine (PDA) can be formed by monomeric self-polymerization in water. This convenient behavior was exploited to prepare a molecularly imprinted polymer (MIP) layer on the surface of multi-walled carbon nanotubes (MWCNTs) with sunset yellow (SY) as a template molecule. The prepared nanocomposites were characterized, and their electrochemical behavior towards SY was investigated. Under the optimized conditions, a glassy carbon electrode modified with the imprinted nanocomposite showed a highly selective and ultrasensitive electrochemical response to SY compared with the performance of control electrodes and previously reported electrochemical sensors for SY. The improved behavior of the developed sensor can be attributed to its superficial highly matched imprinted cavities on the excellent electrocatalytic matrix of MWCNTs and the electronic barrier of the non-imprinted PDA to outside molecules. The fabricated sensor expressed a linear relationship to SY concentrations from 2.2nM to 4.64μM with a detection limit of 1.4nM (S/N = 3). The sensor also exhibited excellent selectivity for SY over its structural analogs, good stability, and adequate reproducibility. The prepared sensor was successfully used to detect SY in real spiked samples. This methodology has potential application value and may be readily adapted to design other PDA-based MIP sensors. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Physico-chemical studies of cuprous oxide (Cu{sub 2}O) nanoparticles coated on amorphous carbon nanotubes (α-CNTs)

    Energy Technology Data Exchange (ETDEWEB)

    Johan, Mohd Rafie, E-mail: mrafiej@um.edu.my; Meriam Suhaimy, Syazwan Hanani; Yusof, Yusliza, E-mail: yus_liza@siswa.um.edu.my

    2014-01-15

    Amorphous carbon nanotubes (α-CNTs) were synthesized by a chemical reaction between ferrocene and ammonium chloride at a temperature (∼250 °C) in an air furnace. As- synthesized α-CNTs were purified with deionized water and hydrochloric acid. A purified α-CNTs were hybridized with cuprous oxide nanoparticles (Cu{sub 2}O) through a simple chemical process. Morphology of the samples was analyzed with field emission scanning electron microscope (FESEM) and transmission electron microscopy (TEM). Fourier transform infrared (FTIR) spectra showed the attachment of acidic functional groups onto the surface of α-CNTs and the formation of hybridized α-CNTs-Cu{sub 2}O. Raman spectra reveal the amorphous nature of the carbon. X-ray diffraction (XRD) pattern confirmed the amorphous phase of the carbon and the formation of Cu{sub 2}O crystalline phase. The coating of Cu{sub 2}O was confirmed by FESEM, TEM, and XRD. Optical absorption of the samples has also been investigated and the quantum confinement effect was illustrated in the absorption spectra.

  17. 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.

  18. Probing the role of poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) -coated multiwalled carbon nanotubes in the thermal and mechanical properties of polycarbonate nanocomposites

    KAUST Repository

    Zhou, Jian

    2014-03-05

    The role played by multiwalled carbon nanotubes (MWCNTs) coated with poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT/PSS) in the thermal and mechanical properties of polycarbonate (PC) nanocomposites was analyzed. We used differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) to demonstrate that the glass transition temperature of polycarbonate nanocomposites decreased whereas the storage modulus of the samples increased by including PEDOT/PSS-coated MWCNTs. These results indicated that PEDOT/PSS acts as an antiplasticizer. We attributed the enhancement of the storage modulus to the strong hydrogen bonding between PSS and the PC matrix and the reduction of the free volume in the PC matrix due to the shrinkage of PEDOT/PSS upon heating. We also investigated changes in the thermal conductivity and thermal degradation behavior of the nanocomposites. The results indicated that PEDOT/PSS did not play a significant role in improving the thermal conductivity and thermal stability of PC nanocomposites. The relative improvements in the conductivity and thermal stability of the samples that contained PEDOT/PSS were attributed to the better dispersion of the MWCNTs in the PC matrix. © 2014 American Chemical Society.

  19. Molecular Dynamics Study on the Effect of Temperature on the Tensile Properties of Single-Walled Carbon Nanotubes with a Ni-Coating

    Directory of Open Access Journals (Sweden)

    Fulong Zhu

    2015-01-01

    Full Text Available The effect of temperature on the tensile behavior of the armchair (6, 6 single-walled carbon nanotubes with a Ni-coating (SWCNT-Ni was investigated using molecular dynamics (MD methods. The mechanical properties of SWCNT-Ni and SWCNT were calculated and analyzed at different temperatures in the range from 220 K to 1200 K. From the MD results, temperature was determined to be the crucial factor affecting the mechanical properties of SWCNT-Ni and SWCNT. After coating nickel atoms onto the surface of a SWCNT, the Young’s modulus, tensile strength, and tensile failure strain of SWCNT were greatly reduced with temperature rising, indicating that the nickel atoms on the surface of SWCNT degrade its mechanical properties. However, at high temperature, the Young’s modulus of both the SWCNT and the SWCNT-Ni exhibited significantly greater temperature sensitivity than at low temperatures, as the mechanical properties of SWCNT-Ni were primarily dominated by temperature and C-Ni interactions. During these stretching processes at different temperatures, the nickel atoms on the surface of SWCNT-Ni could obtain the amount of energy sufficient to break the C-C bonds as the temperature increases.

  20. Investigations of carbon nanotubes and polyacrylonitrile composites for flexible textronics

    Science.gov (United States)

    Sowiński, J.; Wróblewski, G.; Janczak, D.; Jakubowska, M.

    2017-08-01

    Thin composite layers based on polyacrylonitrile (PAN) and carbon nanotubes (CNT) were fabricated by means of spray coating with pneumatic atomization. Research was conducted to achieve transparent and flexible electrodes. Prepared suspensions in different proportions of functional phase provided good dispersion quality of CNTs and the stability. The carbon nanotubes were dispersed in dimethylformamide and then added to polyacrylonitrile solution. Suspension was sprayed onto Polyethylene terephthalate (PET) foil. After thermal treatment, samples were mechanically and electrically tested. Thanks to carbon nanomaterials used in prepared coatings, high electrical conductivity and mechanical resistance was observed. Use of a polyacrylonitrile guarantee the flexibility of electrodes and high potential in integration with polyacrylonitrile based fabrics.

  1. Theoretical properties of carbon nanotubes

    CERN Document Server

    Palser, A H

    2000-01-01

    Carbon nanotubes are invariably terminated with hemi-fullerene caps. In order to investigate the effect of these caps on the electronic structure, a method is developed to enumerate every hemi-fullerene cap which is commensurate with a given nanotube body. This algorithm is then applied to nanotubes for which I + m <= 25. The results of this algorithm are then used to study the effects of caps with different symmetries on the electronic structure of metallic and semi-conducting nanotubes within the Hueckel model. It is found that caps can cause localised and resonance states, although the likelihood of localised states occurring in capped metallic nanotubes is shown to be small. In addition, caps induce a non-uniform charge distribution, in which negative charge tends to accumulate on pentagon vertices. The thesis ends by describing two new density matrix methods for performing linear-scaling electronic-structure calculations within the independent electron approximation. Example calculations demonstrate t...

  2. Microenvironment effects in electrocatalysis: ionic-liquid-like coating on carbon nanotubes enhances the Pd-electrocatalytic alcohol oxidation.

    Science.gov (United States)

    Li, Shuwen; Dong, Zhengping; Yang, Honglei; Guo, Shujing; Gou, Galian; Ren, Ren; Zhu, Zhejun; Jin, Jun; Ma, Jiantai

    2013-02-11

    A new catalyst consisting of ionic liquid (IL)-functionalized carbon nanotubes (CNTs) obtained through 1,3-dipolar cycloaddition support-enhanced electrocatalytic Pd nanoparticles (Pd@IL(Cl(-))-CNTs) was successfully fabricated and applied in direct ethanol alkaline fuel cells. The morphology, structure, component and stability of Pd@IL(Cl(-))-CNTs were systematic characterized by transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), Raman spectra, thermogravimetric analysis (TGA) and X-ray diffraction (XRD). The new catalyst exhibited higher electrocatalytic activity, better tolerance and electrochemical stability than the Pd nanoparticles (NPs) immobilized on CNTs (Pd@CNTs), which was ascribed to the effects of the IL, larger electrochemically active surface area (ECSA), and greater processing performance. Cyclic voltammograms (CVs) at various scan rates illustrated that the oxidation behaviors of ethanol at all electrodes were controlled by diffusion processes. The investigation of the different counteranions demonstrated that the performance of the IL-CNTs hybrid material was profoundly influenced by the subtly varied structures of the IL moiety. All the results indicated that the Pd@IL(Cl(-))-CNTs catalyst is an efficient anode catalyst, which has potential applications in direct ethanol fuel cells and the strategy of IL functionalization of CNTs could be available to prepare other carbonaceous carrier supports to enhance the dispersivity, stability, and catalytic performance of metal NPs as well. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Miniemulsion copolymerization of (meth)acrylates in the presence of functionalized multiwalled carbon nanotubes for reinforced coating applications.

    Science.gov (United States)

    Pérez-Martínez, Bertha T; Farías-Cepeda, Lorena; Ovando-Medina, Víctor M; Asua, José M; Rosales-Marines, Lucero; Tomovska, Radmila

    2017-01-01

    Film forming, stable hybrid latexes made of methyl metacrylate (MMA), butyl acrylate (BA) and 2-hydroxyethyl methacrylate (HEMA) copolymer reinforced with modified multiwalled carbon nanotubes (MWCNTs) were synthesized by in situ miniemulsion polymerization. The MWCNTs were pretreated by an air sonication process and stabilized by polyvinylpyrrolidone. The presence of the MWCNTs had no significant effect on the polymerization kinetics, but strongly affected the polymer characteristics (Tg and insoluble polymer fraction). The performance of the in situ composites was compared with that of the neat polymer dispersion as well as with those of the polymer/MWCNT physical blends. The in situ composites showed the presence of an additional phase likely due to the strong interaction between the polymer and MWNCTs (including grafting) that reduced the mobility of the polymer chains. As a result, a substantial increase of both the storage and the loss moduli was achieved. At 60 °C, which is above the main transition region of the polymer, the in situ composites maintained the reinforcement, whereas the blends behaved as a liquid-like material. This suggests the formation of a 3D network, in good agreement with the high content of insoluble polymer in the in situ composites.

  4. Carbon nanotube based multi electrode arrays for neuronal interfacing: progress and prospects

    Directory of Open Access Journals (Sweden)

    Yael eHanein

    2013-01-01

    Full Text Available Carbon nanotube coatings have been demonstrated over the past several years as a promising material for neuronal interfacing applications. In particular, in the realm of neuronal implants, carbon nanotubes have major advantages owing to their unique mechanical and electrical properties. Here we review recent investigations utilizing carbon nanotubes in neuro-interfacing applications. Cell adhesion, neuronal engineering and multi electrode recordings with carbon nanotubes are described. We also highlight prospective advances in this field, in particular, progress towards flexible, bio-compatible carbon nanotubes technology.

  5. 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 ...

  6. Titanate nanotube coatings on biodegradable photopolymer scaffolds

    Energy Technology Data Exchange (ETDEWEB)

    Beke, S., E-mail: szabolcs.beke@iit.it [Department of Nanophysics, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genova (Italy); Kőrösi, L. [Department of Biotechnology, Nanophage Therapy Center, Enviroinvest Corporation, Kertváros u. 2, H-7632, Pécs (Hungary); Scarpellini, A. [Department of Nanochemistry, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genova (Italy); Anjum, F.; Brandi, F. [Department of Nanophysics, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genova (Italy)

    2013-05-01

    Rigid, biodegradable photopolymer scaffolds were coated with titanate nanotubes (TNTs) by using a spin-coating method. TNTs were synthesized by a hydrothermal process at 150 °C under 4.7 bar ambient pressure. The biodegradable photopolymer scaffolds were produced by mask-assisted excimer laser photocuring at 308 nm. For scaffold coating, a stable ethanolic TNT sol was prepared by a simple colloid chemical route without the use of any binding compounds or additives. Scanning electron microscopy along with elemental analysis revealed that the scaffolds were homogenously coated by TNTs. The developed TNT coating can further improve the surface geometry of fabricated scaffolds, and therefore it can further increase the cell adhesion. Highlights: ► Biodegradable scaffolds were produced by mask-assisted UV laser photocuring. ► Titanate nanotube deposition was carried out without binding compounds or additives. ► The titanate nanotube coating can further improve the surface geometry of scaffolds. ► These reproducible platforms will be of high importance for biological applications.

  7. Universally dispersible carbon nanotubes.

    Science.gov (United States)

    Prevoteau, Alexandre; Soulié-Ziakovic, Corinne; Leibler, Ludwik

    2012-12-12

    We show that supramolecular chemistry provides a convenient tool to prepare carbone nanotubes (CNTs) that can be dispersed in solvents of any chemical nature, easily recovered and redispersed. Thymine-modified CNTs (CNT-Thy) can be dispersed in solution in the presence of diaminotriazine (DAT) end-functionalized polymers, through supramolecular Thy/DAT association. DAT-polymer chains are selected according to the solvent chemical nature: polystyrene (PS) for hydrophobic/low polarity solvents and a propylene oxide/ethylene oxide copolymer (predominantly propylene oxide based, PPO/PEO) for polar solvents or water. Long-term stable supramolecular CNT dispersions are reversibly aggregated by adding a few droplets of a selective dissociating agent of the Thy/DAT association (DMSO). CNT-Thy, simply recycled by centrifugation or filtration, can be redispersed in another solvent in presence of a suitable soluble DAT-polymer. Dispersion and aggregation can also be switched on and off by choosing a polymer for which a given solvent is close to Θ-conditions, e.g., PS in cyclohexane or PPO/PEO in water.

  8. Atomic layer deposition coating of carbon nanotubes with zinc oxide causes acute phase immune responses in human monocytes in vitro and in mice after pulmonary exposure.

    Science.gov (United States)

    Dandley, Erinn C; Taylor, Alexia J; Duke, Katherine S; Ihrie, Mark D; Shipkowski, Kelly A; Parsons, Gregory N; Bonner, James C

    2016-06-08

    Atomic layer deposition (ALD) is a method for applying conformal nanoscale coatings on three-dimensional structures. We hypothesized that surface functionalization of multi-walled carbon nanotubes (MWCNTs) with polycrystalline ZnO by ALD would alter pro-inflammatory cytokine expression by human monocytes in vitro and modulate the lung and systemic immune response following oropharyngeal aspiration in mice. Pristine (U-MWCNTs) were coated with alternating doses of diethyl zinc and water over increasing ALD cycles (10 to 100 ALD cycles) to yield conformal ZnO-coated MWCNTs (Z-MWCNTs). Human THP-1 monocytic cells were exposed to U-MWCNTs or Z-MWCNTs in vitro and cytokine mRNAs measured by Taqman real-time RT-PCR. Male C57BL6 mice were exposed to U- or Z-MWCNTs by oropharyngeal aspiration (OPA) and lung inflammation evaluated at one day post-exposure by histopathology, cytokine expression and differential counting of cells in bronchoalveolar lavage fluid (BALF) cells. Lung fibrosis was evaluated at 28 days. Cytokine mRNAs (IL-6, IL-1β, CXCL10, TNF-α) in lung, heart, spleen, and liver were quantified at one and 28 days. DNA synthesis in lung tissue was measured by bromodeoxyuridine (BrdU) uptake. ALD resulted in a conformal coating of MWCNTs with ZnO that increased proportionally to the number of coating cycles. Z-MWCNTs released Zn(+2) ions in media and increased IL-6, IL-1β, CXCL10, and TNF-α mRNAs in THP-1 cells in vitro. Mice exposed to Z-MWCNTs by OPA had exaggerated lung inflammation and a 3-fold increase in monocytes and neutrophils in BALF compared to U-MWCNTs. Z-MWCNTs, but not U-MWCNTs, induced IL-6 and CXCL10 mRNA and protein in the lungs of mice and increased IL-6 mRNA in heart and liver. U-MWCNTs but not Z-MWCNTs stimulated airway epithelial DNA synthesis in vivo. Lung fibrosis at 28 days was not significantly different between mice treated with U-MWCNT or Z-MWCNT. Pulmonary exposure to ZnO-coated MWCNTs produces a systemic acute phase response that

  9. High loading of uniformly dispersed Pt nanoparticles on polydopamine coated carbon nanotubes and its application in simultaneous determination of dopamine and uric acid.

    Science.gov (United States)

    Lin, Mouhong; Huang, Haoliang; Liu, Yingju; Liang, Canjian; Fei, Shidong; Chen, Xiaofen; Ni, Chunlin

    2013-02-15

    Multiwalled carbon nanotubes (MWCNT) were homogeneously covered with a bio-functional polydopamine (PDOP) by a simple dip-coating approach in mild basic solution. Then, uniformly dispersed and highly loaded platinum nanoparticles (PtNPs) were deposited on MWCNT@PDOP by a mild reductant, and were characterized by transmission electron microscopy and x-ray photoelectron spectroscopy. Afterwards, this nanocomposite was modified on the glass carbon electrode and applied to simultaneously determine dopamine (DA) and uric acid (UA) by differential pulse voltammetry (DPV). Results showed that a linear electro-oxidation response was found for DA and UA in the range of 0.25-20 μM and 0.3-13 μM with the detection limit (S/N = 3) of 0.08 μM and 0.12 μM, respectively. In addition, the detection sensitivities for DA and UA by DPV were 1.03 μA μM(-1) and 2.09 μA μM(-1), respectively, which were much higher than those from a cyclic voltammogram. Finally, the reproducibility and stability of the nanocomposite were also evaluated, demonstrating that such MWCNT@PDOP@PtNPs can be a promising candidate for advanced electrode material in electrochemical sensing and other electrocatalytic applications.

  10. Creep- and fatigue-resistant, rapid piezoresistive responses of elastomeric graphene-coated carbon nanotube aerogels over a wide pressure range.

    Science.gov (United States)

    Tsui, Michelle N; Islam, Mohammad F

    2017-01-19

    Lightweight, flexible piezoresistive materials with wide operational pressure ranges are in demand for applications such as human physical activity and health monitoring, robotics, and for functional interfacing between living systems and wearable electronics. Piezoresistivity of many elastomeric foams of polymers and carbon allotropes satisfies much of the required characteristics for these applications except creep and fatigue resistance due to their viscoelasticity, critically limiting the reliability and lifetime of integrated devices. We report the piezoresistive responses from aerogels of graphene-coated single-walled carbon nanotubes (SWCNTs), made using a facile and versatile sol-gel method. Graphene crosslinks the junctions of the underlying random network of SWCNTs, generating lightweight elastomeric aerogels with a mass density of ≈11 mg mL-1 (volume fraction ≈7.7 × 10-3) and a Young's modulus of ≈0.4 MPa. The piezoresistivity of these aerogels spans wide compressive pressures up to at least 120 kPa with sensitivity that exhibit ultrafast temporal responses of <27 ms and <3% delay ratio over 104 compressive loading-unloading cycles at rates between 0.1-10 Hz. Most importantly, the piezoresistive responses do not show any creep at least for 1 hour and 80 kPa of compressive static loading. We suggest that the fatigue- and creep-resistant, ultrafast piezoresistive responses of these elastomeric aerogels are highly attractive for use in dynamic and static lightweight, pressure sensing applications such as human activity monitoring and soft robotics.

  11. Mapping differential cellular protein response of mouse alveolar epithelial cells to multi-walled carbon nanotubes as a function of atomic layer deposition coating.

    Science.gov (United States)

    Hilton, Gina M; Taylor, Alexia J; Hussain, Salik; Dandley, Erinn C; Griffith, Emily H; Garantziotis, Stavros; Parsons, Gregory N; Bonner, James C; Bereman, Michael S

    2017-04-01

    Carbon nanotubes (CNTs), a prototypical engineered nanomaterial, have been increasingly manufactured for a variety of novel applications over the past two decades. However, since CNTs possess fiber-like shape and cause pulmonary fibrosis in rodents, there is concern that mass production of CNTs will lead to occupational exposure and associated pulmonary diseases. The aim of this study was to use contemporary proteomics to investigate the mechanisms of cellular response in E10 mouse alveolar epithelial cells in vitro after exposure to multi-walled CNTs (MWCNTs) that were functionalized by atomic layer deposition (ALD). ALD is a method used to generate highly uniform and conformal nanoscale thin-film coatings of metals to enhance novel conductive properties of CNTs. We hypothesized that specific types of metal oxide coatings applied to the surface of MWCNTs by ALD would determine distinct proteomic profiles in mouse alveolar epithelial cells in vitro that could be used to predict oxidative stress and pulmonary inflammation. Uncoated (U)-MWCNTs were functionalized by ALD with zinc oxide (ZnO) to yield Z-MWCNTs or aluminum oxide (Al2O3) to yield A-MWCNTs. Significant differential protein expression was found in the following critical pathways: mTOR/eIF4/p70S6K signaling and Nrf-2 mediated oxidative stress response increased following exposure to Z-MWCNTs, interleukin-1 signaling increased following U-MWCNT exposure, and inhibition of angiogenesis by thrombospondin-1, oxidative phosphorylation, and mitochondrial dysfunction increased following A-MWCNT exposure. This study demonstrates that specific types of metal oxide thin film coatings applied by ALD produce distinct cellular and biochemical responses related to lung inflammation and fibrosis compared to uncoated MWCNT exposure in vitro.

  12. Facile modification of multi-walled carbon nanotubes-polymeric ionic liquids-coated solid-phase microextraction fibers by on-fiber anion exchange.

    Science.gov (United States)

    Feng, Juanjuan; Sun, Min; Bu, Yanan; Luo, Chuannan

    2015-05-08

    In situ anion exchange has been proved to be an efficient method for facile modification of polymeric ionic liquids (PILs)-based stationary phases. In this work, an on-fiber anion exchange process was utilized to tune the extraction performance of a multi-walled carbon nanotubes (MWCNTs)-poly(1-vinyl-3-octylimidazolium bromide) (poly(VOIm(+)Br(-)))-coated solid-phase microextraction (SPME) fiber. MWCNTs were first coated onto the stainless steel wire through a layer-by-layer fabrication method and then the PILs were coated onto the MWCNTs physically. Anion of the MWCNTs-poly(VOIm(+)Br(-)) fiber was changed into bis(triflroromethanesulfonyl)imide (NTf2(-)) and 2-naphthalene-sulfonate (NapSO3(-)) by on-fiber anion exchange. Coupled to gas chromatography, the MWCNTs-poly(VOIm(+)Br(-)) fiber showed acceptable extraction efficiency for hydrophilic and hydrogen-bonding-donating alcohols, with limits of detection (LODs) in the range of 0.005-0.05μgmL(-1); after the anion exchange with NTf2(-), the obtained MWCNTs-poly(VOIm(+)NTf2(-)) fiber brought wide linear ranges for hydrophobic n-alkanes with correlation coefficient (R) ranging from 0.994 to 0.997; aromatic property of the fiber was enhanced by aromatic NapSO3(-) anions to get sufficient extraction capacity for phthalate esters and halogenated aromatic hydrocarbons. The MWCNTs-poly(VOIm(+)NapSO3(-)) fiber was finally applied to determine several halogenated aromatic hydrocarbons in groundwater of industrial park. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. EDITORIAL: Focus on Carbon Nanotubes

    Science.gov (United States)

    2003-09-01

    The study of carbon nanotubes, since their discovery by Iijima in 1991, has become a full research field with significant contributions from all areas of research in solid-state and molecular physics and also from chemistry. This Focus Issue in New Journal of Physics reflects this active research, and presents articles detailing significant advances in the production of carbon nanotubes, the study of their mechanical and vibrational properties, electronic properties and optical transitions, and electrical and transport properties. Fundamental research, both theoretical and experimental, represents part of this progress. The potential applications of nanotubes will rely on the progress made in understanding their fundamental physics and chemistry, as presented here. We believe this Focus Issue will be an excellent guide for both beginners and experts in the research field of carbon nanotubes. It has been a great pleasure to edit the many excellent contributions from Europe, Japan, and the US, as well from a number of other countries, and to witness the remarkable effort put into the manuscripts by the contributors. We thank all the authors and referees involved in the process. In particular, we would like to express our gratitude to Alexander Bradshaw, who invited us put together this Focus Issue, and to Tim Smith and the New Journal of Physics staff for their extremely efficient handling of the manuscripts. Focus on Carbon Nanotubes Contents Transport theory of carbon nanotube Y junctions R Egger, B Trauzettel, S Chen and F Siano The tubular conical helix of graphitic boron nitride F F Xu, Y Bando and D Golberg Formation pathways for single-wall carbon nanotube multiterminal junctions Inna Ponomareva, Leonid A Chernozatonskii, Antonis N Andriotis and Madhu Menon Synthesis and manipulation of carbon nanotubes J W Seo, E Couteau, P Umek, K Hernadi, P Marcoux, B Lukic, Cs Mikó, M Milas, R Gaál and L Forró Transitional behaviour in the transformation from active end

  14. Dispersions of Carbon nanotubes in Polymer Matrices

    Science.gov (United States)

    Wise, Kristopher Eric (Inventor); Park, Cheol (Inventor); Siochi, Emilie J. (Inventor); Harrison, Joycelyn S. (Inventor); Lillehei, Peter T. (Inventor); Lowther, Sharon E. (Inventor)

    2010-01-01

    Dispersions of carbon nanotubes exhibiting long term stability are based on a polymer matrix having moieties therein which are capable of a donor-acceptor complexation with carbon nanotubes. The carbon nanotubes are introduced into the polymer matrix and separated therein by standard means. Nanocomposites produced from these dispersions are useful in the fabrication of structures, e.g., lightweight aerospace structures.

  15. Electric conductivity of high explosives with carbon nanotubes

    Science.gov (United States)

    Rubtsov, I. A.; Pruuel, E. R.; Ten, K. A.; Kashkarov, A. O.; Kremenko, S. I.

    2017-09-01

    The paper presents a technique for introducing carbon nanotubes into high explosives (HEs). For a number of explosives (trinitrotoluene, pentaerythritol tetranitrate, benzotrifuroxan), it was possible to achieve the appearance of conductivity by adding a small amount (up to 1% by mass) of single-walled carbon nanotubes TUBALL COATE H2O (CNTs) produced by OCSiAl. Thus it is possible to reduce the sensitivity of explosives to static electricity by adding an insignificant part of conductive nanotubes. This will increase safety of HEs during production and application and will reduce the number of accidents.

  16. Carbon nanotube-polymer composite actuators

    Science.gov (United States)

    Gennett, Thomas [Denver, CO; Raffaelle, Ryne P [Honeoye Falls, NY; Landi, Brian J [Rochester, NY; Heben, Michael J [Denver, CO

    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.

  17. Carbon nanotubes: synthesis, structure, functionalization, and characterization.

    Science.gov (United States)

    Zamolo, Valeria Anna; Vazquez, Ester; Prato, Maurizio

    2014-01-01

    Carbon nanotubes have generated great expectations in the scientific arena, mainly due to their spectacular properties, which include a high aspect ratio, high strain resistance, and high strength, along with high conductivities. Nowadays, carbon nanotubes are produced by a variety of methods, each of them with advantages and disadvantages. Once produced, carbon nanotubes can be chemically modified, using a wide range of chemical reactions. Functionalization makes these long wires much easier to manipulate and dispersible in several solvents. In addition, the properties of carbon nanotubes can be combined with those of organic appendages. Finally, carbon nanotubes need to be carefully characterized, either as pristine or modified materials.

  18. Carbon nanotubes and methods of making carbon nanotubes

    KAUST Repository

    Basset, Jean-Marie

    2017-04-27

    Embodiments of the present disclosure provide for methods that can be used to produce carbon nanotubes (hereinafter CNT) having an inner diameter about 5-55 nm, methods of tuning the inner diameter of CNTs (e.g., by adjusting reaction pressure), CNTs having an inner diameter of greater than 20 nm or more, and the like.

  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. Hydrogen storage in carbon nanotubes.

    Science.gov (United States)

    Hirscher, M; Becher, M

    2003-01-01

    The article gives a comprehensive overview of hydrogen storage in carbon nanostructures, including experimental results and theoretical calculations. Soon after the discovery of carbon nanotubes in 1991, different research groups succeeded in filling carbon nanotubes with some elements, and, therefore, the question arose of filling carbon nanotubes with hydrogen by possibly using new effects such as nano-capillarity. Subsequently, very promising experiments claiming high hydrogen storage capacities in different carbon nanostructures initiated enormous research activity. Hydrogen storage capacities have been reported that exceed the benchmark for automotive application of 6.5 wt% set by the U.S. Department of Energy. However, the experimental data obtained with different methods for various carbon nanostructures show an extreme scatter. Classical calculations based on physisorption of hydrogen molecules could not explain the high storage capacities measured at ambient temperature, and, assuming chemisorption of hydrogen atoms, hydrogen release requires temperatures too high for technical applications. Up to now, only a few calculations and experiments indicate the possibility of an intermediate binding energy. Recently, serious doubt has arisen in relation to several key experiments, causing considerable controversy. Furthermore, high hydrogen storage capacities measured for carbon nanofibers did not survive cross-checking in different laboratories. Therefore, in light of today's knowledge, it is becoming less likely that at moderate pressures around room temperature carbon nanostructures can store the amount of hydrogen required for automotive applications.

  1. HP-SPME of volatile polycyclic aromatic hydrocarbons from water using multiwalled carbon nanotubes coated on a steel fiber through electrophoretic deposition

    Energy Technology Data Exchange (ETDEWEB)

    Maghsoudi, S.; Noroozian, E. [Shahid Bahonar Univ., Kerman (Iran, Islamic Republic of). Dept. of Chemistry

    2012-08-15

    A headspace solid-phase microextraction (SPME) method using a stainless steel wire electrophoretically coated with dodecylsulfate modified multiwalled carbon nanotubes was used for the gas chromatographic (GC) determination of polycyclic aromatic hydrocarbons (PAHs) in aqueous samples. Electrophoretic deposition was easily carried out from an aqueous sodium dodecylsulfate medium. The effects of various parameters on the efficiency of SPME process, such as extraction time, extraction temperature, ionic strength, desorption time, and desorption temperature were studied. Under optimized conditions, the detection limits for the various PAHs studied varied from 0.03 to 0.07 ng mL{sup -1}. The inter-day and intra-day relative standard deviations at a 10 ng mL{sup -1} concentration level (n = 7) using a single-fiber were from 5.5 to 9.7 and 4.1 to 8.5 %, respectively. The fiber-to-fiber RSD% (n = 3) was between 7.3 and 11.1 %. The linear ranges were between 0.1 and 100 ng mL{sup -1}. The method was successfully applied to the analysis of a real sample with the recoveries from 88 to 105 % for 5 ng mL{sup -1} and 89 to 101 % for 0.5 ng mL{sup -1} samples. (orig.)

  2. Carbon nanotubes@silicon dioxide nanohybrids coating for solid-phase microextraction of organophosphorus pesticides followed by gas chromatography-corona discharge ion mobility spectrometric detection.

    Science.gov (United States)

    Saraji, Mohammad; Jafari, Mohammad Taghi; Mossaddegh, Mehdi

    2016-01-15

    A high efficiency solid-phase microextraction (SPME) fiber coated with porous carbon nanotubes-silicon dioxide (CNTs-SiO2) nanohybrids was synthesized and applied for the determination of some organophosphorus pesticides (OPPs) in vegetables, fruits and water samples. Gas chromatography-corona discharge ion mobility spectrometry was used as the detection system. Glucose, as a biocompatible compound, was used for connecting CNT and SiO2 during a hydrothermal process. The electrospinning technique was also applied for the fiber preparation. The parameters affecting the efficiency of extraction, including stirring rate, salt effect, extraction temperature, extraction time, desorption temperature and desorption time, were investigated and optimized. The developed CNTs@SiO2 fiber presented better extraction efficiency than the commercial SPME fibers (PA, PDMS, and PDMS-DVB). The intra- and inter-day relative standard deviations were found to be lower than 6.2 and 9.0%, respectively. For water samples, the limits of detection were in the range of 0.005-0.020 μg L(-1) and the limits of quantification were between 0.010 and 0.050 μg L(-1). The results showed a good linearity in the range of 0.01-3.0 μg L(-1) for the analytes. The spiking recoveries ranged from 79 (± 9) to 99 (± 8). The method was successfully applied for the determination of OPPs in real samples. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. High-performance dye-sensitized solar cells with gel-coated binder-free carbon nanotube films as counter electrode

    Energy Technology Data Exchange (ETDEWEB)

    Mei Xiaoguang; Cho, Swee Jen; Fan Benhu; Ouyang Jianyong, E-mail: mseoj@nus.edu.sg [Department of Materials Science and Engineering, Faculty of Engineering, National University of Singapore, 117574 (Singapore)

    2010-10-01

    High-performance dye-sensitized solar cells (DSCs) with binder-free films of carbon nanotubes (CNTs), including single-walled CNTs (SWCNTs) and multi-walled CNTs (MWCNTs), as the counter electrode are reported. The CNT films were fabricated by coating gels, which were prepared by dispersing CNTs in low-molecular-weight poly(ethylene glycol) (PEG) through mechanical grinding and subsequent ultrasonication, on fluorine tin oxide (FTO) glass. PEG was removed from the CNT films through heating. These binder-free CNT films were rough and exhibited good adhesion to substrates. They were used as the counter electrode of DSCs. The DSCs with SWCNT or MWCNT counter electrodes exhibited a light-to-electricity conversion efficiency comparable with that with the conventional platinum (Pt) counter electrode, when the devices were tested immediately after device fabrication. The DSCs with an SWCNT counter electrode exhibited good stability in photovoltaic performance. The efficiency did not decrease after four weeks. On the other hand, DSCs with the MWCNT or Pt counter electrode exhibited a remarkable decrease in the photovoltaic efficiency after four weeks. The high photovoltaic performance of these DSCs is related to the excellent electrochemical catalysis of CNTs on the redox of the iodide/triiodide pair, as revealed by the cyclic voltammetry and ac impedance spectroscopy.

  4. Super-aligned carbon nanotube films with a thin metal coating as highly conductive and ultralight current collectors for lithium-ion batteries

    Science.gov (United States)

    Wang, Ke; Wu, Yang; Wu, Hengcai; Luo, Yufeng; Wang, Datao; Jiang, Kaili; Li, Qunqing; Li, Yadong; Fan, Shoushan; Wang, Jiaping

    2017-05-01

    Cross-stacked super-aligned carbon nanotube (SACNT) films are promising for use as current collectors in lithium-ion batteries because of their outstanding capability to decrease the weight and thickness of inactive material and strong adhesion to the electrodes. However, the relatively poor conductivity of SACNT films may limit their application to large-size electrodes or at high current rate. Herein, a facile approach is proposed to improve the conductivity of SACNT films by electron-beam deposition of a thin metal film on their surface. Such modification lowers the sheet resistance by three orders of magnitude while keeping the extremely small fraction of SACNT current collectors. The metal-coated SACNT films strongly inhibit polarization during the electrochemical reaction, resulting in improved cell performance compared with that of metal and uncoated CNT current collectors. The improvement in conductivity and cell performance achieved by this approach is so large that the effect of the increase of inactive material is overwhelmed, leading to increased gravimetric energy density.

  5. A direct urea microfluidic fuel cell with flow-through Ni-supported-carbon- nanotube-coated sponge as porous electrode

    Science.gov (United States)

    Zhang, Huimin; Wang, Yifei; Wu, Zucheng; Leung, Dennis Y. C.

    2017-09-01

    A direct urea microfluidic fuel cell (UMFC) is demonstrated using a Ni-supported-carbon-nanotube-coated sponge (Ni/CNT@Sponge) as the flow-through porous anode. Ni/CNT@Sponge electrode is prepared through Ni/CNT composite synthesis followed by sponge dipping-drying process. Ni/CNT catalyst shows better performance to urea electrooxidation than Ni/C. The three-dimensional architecture of Ni/CNT@Sponge can provide high effective active area, which enhances the UMFC cell performance. The UMFC works in an alkaline and an acid environment at the anode and cathode respectively, achieving a high theoretical OCV of 1.976 V. With 3 M urea in 3 M KOH as anolyte, 1.5 M H2SO4 as the catholyte, an OCV of 0.92 V at 20 °C can be obtained. Peak power density and maximum current density of 3.9 mW cm-2 and 23 mA cm-2 can be achieved, respectively, which increase to 6.6 mW cm-2 and 33 mA cm-2, respectively when the temperature is increased to 45 °C. This work develops a new type of urea microfluidic fuel cell, also opens up a promising approach for urea-rich wastewater treatment.

  6. Dry Sintered Metal Coating of Halloysite Nanotubes

    Directory of Open Access Journals (Sweden)

    James C. Nicholson

    2016-09-01

    Full Text Available Halloysite nanotubes (HNTs are a naturally-occurring aluminosilicate whose dimensions measure microns in length and tens of nanometers in diameter. Bonding defects between the alumina and silica lead to net negative and positive charges on the exterior and interior lumen, respectively. HNTs have been shown to enhance the material properties of polymer matrices and enable the sustained release of loaded chemicals, drugs, and growth factors. Due to the net charges, these nanotubes can also be readily coated in layered-depositions using the HNT exterior lumen’s net negative charge as the basis for assembly. These coatings are primarily done through wet chemical processes, the majority of which are limited in their use of desired chemicals, due to the polarity of the halloysite. Furthermore, this restriction in the type of chemicals used often requires the use of more toxic chemicals in place of greener options, and typically necessitates the use of a significantly longer chemical process to achieve the desired coating. In this study, we show that HNTs can be coated with metal acetylacetonates—compounds primarily employed in the synthesis of nanoparticles, as metal catalysts, and as NMR shift reagents—through a dry sintering process. This method was capable of thermally decaying the metal acetylacetonate, resulting in a free positively-charged metal ion that readily bonded to the negatively-charged HNT exterior, resulting in metallic coatings forming on the HNT surface. Our coating method may enable greater deposition of coated material onto these nanotubes as required for a desired application. Furthermore, the use of chemical processes using toxic chemicals is not required, thus eliminating exposure to toxic chemicals and costs associated with the disposal of the resultant chemical waste.

  7. Polypropylene membrane coated with carbon nanotubes functionalized with chitosan: Application in the microextraction of polychlorinated biphenyls and polybrominated diphenyl ethers from environmental water samples.

    Science.gov (United States)

    Ge, Dandan; Lee, Hian Kee

    2015-08-21

    Acid oxidized multi-walled carbon nanotubes (CNTs) functionalized with chitosan were coated on polypropylene membrane and used as sorbent to extract trace polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) from environmental water samples. The analytes were extracted by the hydrophobic interaction between analytes and the functionalized CNTs. The chitosan polymer coating also contributed to extraction efficiency. Microextraction conditions (different types of desorption solvent, extraction time, salt concentration, stirring rate and desorption time) were optimized by means of orthogonal array design (OAD). A mixed level OAD matrix, OA16 (4(1)×2(12)) was employed for the initial optimization. Based on the results of the first step, n-hexane was chosen as desorption solvent and 5min was selected as desorption time. Extraction time, stirring rate and salt concentration were further optimized in the second step by an OA16 (4(5)) matrix. Under the optimized conditions, calibration curves with coefficients of determination higher than 0.993 over the concentration range of 0.2 and 50ng/ml. Low limits of detection (<0.60ng/l) and acceptable reproducibility with relative standard deviations in the range of 0.17% and 5.01%, were achieved. The developed method was applied to extract PCBs and PBDEs from environmental water samples. The relative recoveries of the analytes spiked into the real water samples ranged from 85.6 to 104.1% at 0.2ng/ml of each analyte, and from 82.4 to 98.6% at 2ng/ml of each analyte. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Enhanced electrochemical stability and charge storage of MnO{sub 2}/carbon nanotubes composite modified by polyaniline coating layer in acidic electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Changzhou; Su, Linghao; Gao, Bo; Zhang, Xiaogang [College of Material Science and Engineering, Nanjing University of Aeronautics and Astronautics, Yudao Street 29, Nanjing 210016 (China)

    2008-10-15

    Manganese dioxide/multiwalled carbon nanotubes (MnO{sub 2}/MWCNTs) were synthesized by chemically depositing MnO{sub 2} onto the surface of MWCNTs wrapped with poly(sodium-p-styrenesulfonate). Then, polyaniline (PANI) with good supercapacitive performance was further coated onto the MnO{sub 2}/MWCNTs composite to form PANI/MnO{sub 2}/MWCNTs organic-inorganic hybrid nanoarchitecture. Electrochemical performance of the hybrid in Na{sub 2}SO{sub 4}-H{sub 2}SO{sub 4} mixed acidic electrolytes was evaluated by cyclic voltammetry (CV) and chronopotentiometry (CP) in detail. Comparative electrochemical tests revealed that the hybrid nanoarchitecture could operate in the acidic medium due to the protective modification of PANI coating layer onto the MnO{sub 2}/MWCNTs composite, and that its electrochemical behavior was greatly dependent upon the concentration of protons in the acidic electrolytes. Here, PANI not only served as a physical barrier to restrain the underlying MnO{sub 2}/MWCNTs composite from reductive-dissolution process so as to make the novel ternary hybrid material work in acidic medium to enhance the utilization of manganese oxide as much as possible, but also was another electroactive material for energy storage in the acidic mixed electrolytes. It was due to the existence of PNAI layer that an even larger specific capacitance (SC) of 384 F g{sup -1} and a much better SC retention of 79.9% over 1000 continuous charge/discharge cycles than those for the MnO{sub 2}/MWCNTs nanocomposite were delivered for the hybrid in the optimum 0.5 M Na{sub 2}SO{sub 4}-0.5 M H{sub 2}SO{sub 4} mixed acidic electrolyte. (author)

  9. Enhanced electrochemical stability and charge storage of MnO{sub 2}/carbon nanotubes composite modified by polyaniline coating layer in acidic electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Yuan Changzhou; Su Linghao; Gao Bo [College of Material Science and Engineering, Nanjing University of Aeronautics and Astronautics, Yudao Street 29, Nanjing 210016 (China); Zhang Xiaogang [College of Material Science and Engineering, Nanjing University of Aeronautics and Astronautics, Yudao Street 29, Nanjing 210016 (China)], E-mail: azhangxg@163.com

    2008-10-15

    Manganese dioxide/multiwalled carbon nanotubes (MnO{sub 2}/MWCNTs) were synthesized by chemically depositing MnO{sub 2} onto the surface of MWCNTs wrapped with poly(sodium-p-styrenesulfonate). Then, polyaniline (PANI) with good supercapacitive performance was further coated onto the MnO{sub 2}/MWCNTs composite to form PANI/MnO{sub 2}/MWCNTs organic-inorganic hybrid nanoarchitecture. Electrochemical performance of the hybrid in Na{sub 2}SO{sub 4}-H{sub 2}SO{sub 4} mixed acidic electrolytes was evaluated by cyclic voltammetry (CV) and chronopotentiometry (CP) in detail. Comparative electrochemical tests revealed that the hybrid nanoarchitecture could operate in the acidic medium due to the protective modification of PANI coating layer onto the MnO{sub 2}/MWCNTs composite, and that its electrochemical behavior was greatly dependent upon the concentration of protons in the acidic electrolytes. Here, PANI not only served as a physical barrier to restrain the underlying MnO{sub 2}/MWCNTs composite from reductive-dissolution process so as to make the novel ternary hybrid material work in acidic medium to enhance the utilization of manganese oxide as much as possible, but also was another electroactive material for energy storage in the acidic mixed electrolytes. It was due to the existence of PNAI layer that an even larger specific capacitance (SC) of 384 F g{sup -1} and a much better SC retention of 79.9% over 1000 continuous charge/discharge cycles than those for the MnO{sub 2}/MWCNTs nanocomposite were delivered for the hybrid in the optimum 0.5 M Na{sub 2}SO{sub 4}-0.5 M H{sub 2}SO{sub 4} mixed acidic electrolyte.

  10. Ferroelectric-carbon nanotube memory devices

    Science.gov (United States)

    Kumar, Ashok; Shivareddy, Sai G.; Correa, Margarita; Resto, Oscar; Choi, Youngjin; Cole, Matthew T.; Katiyar, Ram S.; Scott, James F.; Amaratunga, Gehan A. J.; Lu, Haidong; Gruverman, Alexei

    2012-04-01

    One-dimensional ferroelectric nanostructures, carbon nanotubes (CNT) and CNT-inorganic oxides have recently been studied due to their potential applications for microelectronics. Here, we report coating of a registered array of aligned multi-wall carbon nanotubes (MWCNT) grown on silicon substrates by functional ferroelectric Pb(Zr,Ti)O3 (PZT) which produces structures suitable for commercial prototype memories. Microstructural analysis reveals the crystalline nature of PZT with small nanocrystals aligned in different directions. First-order Raman modes of MWCNT and PZT/MWCNT/n-Si show the high structural quality of CNT before and after PZT deposition at elevated temperature. PZT exists mostly in the monoclinic Cc/Cm phase, which is the origin of the high piezoelectric response in the system. Low-loss square piezoelectric hysteresis obtained for the 3D bottom-up structure confirms the switchability of the device. Current-voltage mapping of the device by conducting atomic force microscopy (c-AFM) indicates very low transient current. Fabrication and functional properties of these hybrid ferroelectric-carbon nanotubes is the first step towards miniaturization for future nanotechnology sensors, actuators, transducers and memory devices.

  11. Carbon Nanotubes Growth on Graphite Fibers

    Science.gov (United States)

    Zhu, Shen; Su, Ching-Hua; Lehoczky, S. L.; Muntele, I.; Ila, D.; Curreri, Peter A. (Technical Monitor)

    2002-01-01

    Carbon nanotubes (CNT) were synthesized on graphite fibers by thermal Chemical Vapor Deposition (CVD). On the fiber surface, iron nanoparticles are coated and act as catalysts for CNT growth. The growth temperature ranges from 550 to 1000 C at an ambient pressure. Methane and hydrogen gases with methane contents of 10% to 100% are used for the CNT synthesis. At high growth temperatures (greater than 800 C), the rapid inter-diffusion of the transition metal iron on the graphite surface results in a rough fiber surface with no CNT grown on the surface. When the growth temperature is relatively low (650 - 800 C), CNT are fabricated on the graphite surface with catalytic particles on the nanotube top ends. Using micro Raman spectroscopy in the breath mode region, single-walled or multi-walled CNT can be determined, depending on methane concentrations.

  12. Modelling Heat Transfer of Carbon Nanotubes

    OpenAIRE

    Yang, Xin-She

    2010-01-01

    Modelling heat transfer of carbon nanotubes is important for the thermal management of nanotube-based composites and nanoelectronic device. By using a finite element method for three-dimensional anisotropic heat transfer, we have simulated the heat conduction and temperature variations of a single nanotube, a nanotube array and a part of nanotube-based composite surface with heat generation. The thermal conductivity used is obtained from the upscaled value from the molecular simulations or ex...

  13. 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

  14. Polyurethane Coatings Reinforced by Halloysite Nanotubes

    Directory of Open Access Journals (Sweden)

    Diethelm Johannsmann

    2013-01-01

    Full Text Available The pencil hardness of a two-component polyurethane coating was improved by adding halloysite nanotubes to the recipe at a weight fraction of less than 10%. The pencil hardness was around F for the unfilled coating and increased to around 2H upon filling. It was important to silanize the surface of the filler in order to achieve good coupling to the matrix. Sonicating the sample during drying also improved the hardness. Scanning electron micrographs suggest that the nanotubes are always well immersed into the bulk of the film. With a thickness between 10 and 20 µm, the optical clarity was good enough to clearly read letters through the film. The films can be used in applications where transparency is required.

  15. Elastic properties of noncarbon nanotubes as compared to carbon nanotubes

    Science.gov (United States)

    Kochaev, Aleksey

    2017-10-01

    A comparative study of stability, structural, and elastic properties of single-wall noncarbon nanotubes, including BN, AlN, GaN, AlP, GaP, and B nanotubes using ab initio simulation is presented. The proposed nanotubes can be found in nature, which is confirmed by calculation of their binding energy. The values of Young's modulus and Poisson's ratio for (0,n ) and (n ,n ) proposed nanotubes with n =3 ⋯20 are obtained. The conception of two-dimensional (2D) Young's modulus of planar and tubular materials was developed. The calculations show that stable forms of boron nitride nanotubes have the 2D Young's modulus almost similar to carbon nanotubes. At the same time, it is stated that boron nanotubes have a higher 2D Young's modulus than any other known carbon and noncarbon nanostructures.

  16. Electrochemical Behavior of Catechol and Hydroquinone at Copper Doped Poly (Methyl Red Coated Hydroxyl Multiwalled Carbon Nanotube Film and Their Simultaneous Determination in Water Samples

    Directory of Open Access Journals (Sweden)

    Ying Zhang

    2014-09-01

    Full Text Available A glassy carbon electrode modified with copper doped poly (methyl red coated hydroxyl multiwalled carbon nanotube film (Cu-PMR/MWCNTs, was developed to serve as a sensor for simultaneous determination of Hydroquinone (HQ and catechol (CC in this paper. The fabricated electrode showed excellent electrocatalytic behaviors towards the oxidation of HQ and CC with the enhancement of the redox peak current and the decrease of the peak-to-peak separation. Under the optimized condition, the individual determination of HQ or CT in their mixtures was performed, the response peak currents of the modified electrodes were linear over ranges of 8.0´10-7~4.0´10-4 M (R2=0.999 for CT and 5.0´10-7~2.0´10-4 M (R2=0.993 for HQ. The sensor also exhibited good sensitivity with the detection limit of 1.0´10-8 mol/L and 5.0´10-8 mol/L for HQ and CT, respectively. The simultaneous determination of HQ and CC was demonstrated by simultaneously changing their concentrations. The reduction peak currents of HQ and CC increased linearly with the concentration of their own in the range of 8´10-7 and 2.0´10-4 M for HQ and CC, with correlation coefficients of 0.994 and 0.995 (S/N=3, respectively. This study provides a new kind of composite modified electrode for electrochemical sensors with good selectivity and strong anti-interference. It has been applied to simultaneous determination of HQ and CT in water sample with high selectivity.

  17. Polymer-assisted deposition of films and preparation of carbon nanotube arrays using the films

    Science.gov (United States)

    Luo, Hongmei; Li, Qingwen; Bauer, Eve; Burrell, Anthony Keiran; McCleskey, Thomas Mark; Jia, Quanxi

    2013-07-16

    Carbon nanotubes were prepared by coating a substrate with a coating solution including a suitable solvent, a soluble polymer, a metal precursor having a first metal selected from iron, nickel, cobalt, and molybdenum, and optionally a second metal selected from aluminum and magnesium, and also a binding agent that forms a complex with the first metal and a complex with the second metal. The coated substrate was exposed to a reducing atmosphere at elevated temperature, and then to a hydrocarbon in the reducing atmosphere. The result was decomposition of the polymer and formation of carbon nanotubes on the substrate. The carbon nanotubes were often in the form of an array on the substrate.

  18. Ultra-thin solution-based coating of molybdenum oxide on multiwall carbon nanotubes for high-performance supercapacitor electrodes

    KAUST Repository

    Shakir, Imran

    2014-02-01

    Uniform and conformal coating of ultrathin molybdenum oxide (MoO 3) thin film onto conducting MWCNTs was successfully synthesized through a facile, nontoxic and generally applicable precipitation method, followed by a simple heat treatment. The ultrathin MoO3 coating enables a fast and reversible redox reaction which improves the specific capacitance by utilizing the maximum number of active sites for the redox reaction, while the high porosity of the MWCNTs facilitates ion migration in the electrolyte and shorten the ion diffusion path. The ultrathin MoO3 coated MWCNTs electrodes show a very high specific capacitance of 1145 Fg -1 in 2 M Na2SO4 aqueous solution when 5 nm thick MoO3 was considered alone despite the low weight percentage of the MoO3 (16wt%). Furthermore, the ultrathin MoO3 coated MWCNTs supercapacitor electrodes exhibited excellent cycling performance of > 97% capacitance retention over 1000 cycles. © 2013 Elsevier Ltd.

  19. Applications of carbon nanotubes in neurobiology.

    Science.gov (United States)

    Malarkey, Erik B; Parpura, Vladimir

    2007-01-01

    Carbon nanotubes are one of the most promising materials for the electronics, computer and aerospace industries. There are numerous properties of carbon nanotubes that make them attractive for applications in neurobiology: small size, flexibility, strength, inertness, electrical conductivity and ease of modification with biological compounds. Here, we discuss the current applications of carbon nanotubes in neuroscience. Carbon nanotubes and their derivatives can be used as substrates/scaffolds for neural cell growth. The chemical properties of carbon nanotubes can be systematically varied by attaching different functional groups; manipulation of the charge carried by functionalized carbon nanotubes can be used to control the outgrowth and branching pattern of neuronal processes. The ease with which carbon nanotubes can be patterned makes them attractive for studying the organization of neural networks and the electrical conductivity of nanotubes can provide a mechanism to monitor or stimulate neurons through the substrate itself. However, it is important to recognize that carbon nanotubes themselves can affect neuronal function, most likely by interaction with ion channels. The use of carbon nanotubes in neurobiology is a promising application that has the potential to develop new methods and techniques to advance the study of neuroscience.

  20. Detection of methane using multi-walled carbon nanotubes

    Indian Academy of Sciences (India)

    Abstract. A sensor for detecting and estimating methane using multi-walled carbon nanotubes (MWCNTs) as the sensing element has been developed for the first time. Silver electrodes have been ink-jet printed on glass substrate over which MWCNT is brush coated to fabricate the sensor element which is of chemoresistive ...

  1. Monitoring structural defects and crystallinity of carbon nanotubes in ...

    Indian Academy of Sciences (India)

    We report the influence of catalyst formulation and reaction temperature on the formation of carbon nanotube (CNT) thin films by the chemical vapour deposition (CVD) method. Thin films of CNTs were grown on Fe–Mo/Al2O3-coated silicon wafer by thermal decomposition of methane at different temperatures ranging from ...

  2. Detection of methane using multi-walled carbon nanotubes

    Indian Academy of Sciences (India)

    A sensor for detecting and estimating methane using multi-walled carbon nanotubes (MWCNTs) as the sensing element has been developed for the first time. Silver electrodes have been ink-jet printed on glass substrate over which MWCNT is brush coated to fabricate the sensor element which is of chemoresistive type.

  3. Carbon Nanotube Network Ambipolar Field-Effect Transistors with 108 On/Off Ratio

    NARCIS (Netherlands)

    Derenskyi, Vladimir; Gomulya, Widianta; Salazar Rios, Jorge Mario; Fritsch, Martin; Fröhlich, Nils; Jung, Stefan; Allard, Sybille; Bisri, Satria Zulkarnaen; Gordiichuk, Pavlo; Herrmann, Andreas; Scherf, Ullrich; Loi, Maria Antonietta

    2017-01-01

    Polymer wrapping is a highly effective method of selecting semiconducting carbon nanotubes and dispersing them in solution. Semi-aligned semiconducting carbon nanotube networks are obtained by blade coating, an effective and scalable process. The field-effect transistor (FET) performance can be

  4. The formation mechanism of chiral carbon nanotubes

    Science.gov (United States)

    Liu, Jing; Liu, Liren; Lu, Junzhe; Zhu, Hengjiang

    2018-02-01

    The nuclei and the formation mechanism of chiral carbon nanotubes, namely, single-, double-, and triple-walled carbon nanotubes are simulated by the first principle density functional theory. The formation mechanism from nuclei to corresponding infinitely long carbon nanotubes occurs spirally and via absorbing carbon atoms layer by layer. Carbon atoms at the open end are metastable state compared with ones in the tube wall or the closed end, which indicate the growth point of chiral carbon nanotubes is located at the open end. Growth of outer layer tubular clusters takes precedence over the inner layer in the process of forming multi-walled nuclear structures. Because of the ratio of carbon atoms at the open end to all carbon atoms decreases, the stability of the tubular clusters increases with their length. The infinitely long carbon nanotubes are obtained by executing periodic boundary conditions depend on corresponding nuclear structures.

  5. Dynamic characteristics of multi-walled carbon nanotubes under a ...

    Indian Academy of Sciences (India)

    walled carbon nanotubes; transverse magnetic field; van der Waals force. 1. Introduction. Since the discovery of carbon nanotubes (CNTs) (Iijima. 1991), extensive research related to the carbon nanotubes in the fields of chemistry, physics, ...

  6. Nickel coating electroplated characterization with and without carbon nanotubes; Caracterizacao de niquel eletrodepositado na presenca de nanotubos de carbono

    Energy Technology Data Exchange (ETDEWEB)

    Lopes, A.C.; Banczek, E.P.; Cunha, M.T.; Rodrigues, P.R.P. [Universidade Estadual do Centro-Oeste, Guarapuava, PR (Brazil). Dept. de Quimica; Costa, I. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Terada, M. [Universidade de Sao Paulo (EPUSP), SP (Brazil). Escola Politecnica. Dept. de Engenharia Metalurgica e de Materiais

    2010-07-01

    The metals have great application, but when their properties are not suitable they should be improved through treatments to increase corrosion resistance, mechanical and wear. The metals electrodeposition such as nickel is one of treatment options. This study aims the development a nickel coating with and without (CNT), obtained by electrodeposition on aluminum alloy AA6061. The nickel electrodeposition was performed with cyclic voltammetry and chronoamperometry. Open circuit potential and anodic polarization curves were carried out samples characterization. The microstructure and the chemical composition of the M{sub x}O{sub z} coating were studied using the scanning electron microscopy, energy dispersion spectroscopy and X-ray diffraction. The results indicated that the nickel coating improve the corrosion resistance of aluminum in the presence of CNT. (author)

  7. Carbon Nanotube Thermoelectric Coolers

    Science.gov (United States)

    2015-02-06

    fitting the sharp features with the Gauss bell curves as was suggested earlier in Ref. (Yang, Fedorov et al. 2012). Comparing the  eG V curves...Yang, Fedorov et al. 2012). Our experimental results suggest that the electric current along the nanotube induces an impressive change of local...fermions, Eur. Phys. J. B (2014) 87: 99 DOI: 10.1140/epjb/e2014-40794-0. 2. Y. Yang, G. Fedorov , J. Zhang, A. Tselev, S. Shafraniuk and P. Barbara

  8. Method of making carbon nanotube composite materials

    Science.gov (United States)

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

    2014-05-20

    The present invention is a method of making a composite polymeric material by dissolving a vinyl thermoplastic polymer, un-functionalized carbon nanotubes and hydroxylated carbon nanotubes and optionally additives in a solvent to make a solution and removing at least a portion of the solvent after casting onto a substrate to make thin films. The material has enhanced conductivity properties due to the blending of the un-functionalized and hydroxylated carbon nanotubes.

  9. Emerging Carbon Nanotube Electronic Circuits, Modeling, and Performance

    OpenAIRE

    Yao Xu; Ashok Srivastava; Sharma, Ashwani K.

    2010-01-01

    Current transport and dynamic models of carbon nanotube field-effect transistors are presented. A model of single-walled carbon nanotube as interconnect is also presented and extended in modeling of single-walled carbon nanotube bundles. These models are applied in studying the performances of circuits such as the complementary carbon nanotube inverter pair and carbon nanotube as interconnect. Cadence/Spectre simulations show that carbon nanotube field-effect transistor circuits can operate a...

  10. 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.

  11. Carbon nanotubes as excitonic insulators.

    Science.gov (United States)

    Varsano, Daniele; Sorella, Sandro; Sangalli, Davide; Barborini, Matteo; Corni, Stefano; Molinari, Elisa; Rontani, Massimo

    2017-11-13

    Fifty years ago Walter Kohn speculated that a zero-gap semiconductor might be unstable against the spontaneous generation of excitons-electron-hole pairs bound together by Coulomb attraction. The reconstructed ground state would then open a gap breaking the symmetry of the underlying lattice, a genuine consequence of electronic correlations. Here we show that this excitonic insulator is realized in zero-gap carbon nanotubes by performing first-principles calculations through many-body perturbation theory as well as quantum Monte Carlo. The excitonic order modulates the charge between the two carbon sublattices opening an experimentally observable gap, which scales as the inverse of the tube radius and weakly depends on the axial magnetic field. Our findings call into question the Luttinger liquid paradigm for nanotubes and provide tests to experimentally discriminate between excitonic and Mott insulators.

  12. Pt-CeO2 coating of carbon nanotubes grown on anode gas diffusion layer of the polymer electrolyte membrane fuel cell.

    Science.gov (United States)

    Fiala, R; Khalakhan, I; Matolínová, I; Václavů, M; Vorokhta, M; Sofer, Z; Huber, S; Potin, V; Matolín, V

    2011-06-01

    The growing of carbon nanotubes on a gas diffusion layer (GDL) was investigated using electron microscopy and photoelectron spectroscopy. The 30 nm thick Pt doped CeO2 layers were deposited by (rf) magnetron sputtering using a CeO2-Pt target on a carbon diffusion layer overgrown by carbon nanotubes. The anode prepared in such a way was tested in the proton exchange membrane fuel cell. Hydrogen/air fuel cell activity measurements normalized to the amount of used Pt revealed high specific power (W mg(-1) Pt). The high activity of this anode with CNT-grown is explained by high specific area of the catalyst, high conductivity of CNT-GDL junction and high activity of platinum present in cationic state Pt2,4+. Very high specific power and low cost together with physical vapor deposition of catalyst makes this anode preparation promising for micro fabrication of fuel cells to power mobile systems.

  13. Carbon nanotube and conducting polymer composites for supercapacitors

    National Research Council Canada - National Science Library

    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 preformed carbon nanotube electrodes, or by electrochemical co-deposition...

  14. Carbon nanostructures and graphite-coated metal nanostructures ...

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 30; Issue 1. Carbon nanostructures and graphite-coated metal nanostructures obtained by pyrolysis of ruthenocene and ruthenocene–ferrocene mixtures. L S Panchakarla A ... Keywords. Carbon nanotubes; nanoparticles; nanorods; pyrolysis; metallocene; FeRu alloy.

  15. Applications of Quantum Chemistry to the Study of Carbon Nanotubes

    Science.gov (United States)

    Jaffe, Richard L.

    2005-01-01

    For several years, scientists at NASA Ames have been studying the properties of carbon nanotubes using various experimental and computational methods. In this talk, I will compare different strategies for using quantum chemistry calculations to describe the electronic structure, deformation and chemical functionalization of single wall carbon nanotubes (SWNT) and the physisorption of small molecules on nanotube surfaces. The SWNT can be treated as an infinite (periodic) or finite length carbon cylinder or as a polycyclic aromatic hydrocarbon (PAH) molecule with an imposed curvature maintained by external constraints (as if it were cut out of the SWNT surface). Calculations are carried out using DFT and MP2 methods and a variety of atomic orbital basis sets from minimal (STO-3G) to valence triple zeta. The optimal approach is based on the particular SWNT property of interest. Examples to be discussed include: nanotube fluorination and other functionalization reactions; coating of nanotubes by water vapor and low-molecular weight organic molecules; and the nature of the interface between SWNT and liquids such as water and amines. In many cases, the quantum chemistry calculations are used to parameterize or validate force fields for molecular dynamics simulations. The results of these calculations have helped explain experimental data and contributed to the design of novel materials and sensors based on carbon nanotubes. Some of this research is described in the following papers:

  16. 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.

  17. 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...

  18. Growing carbon nanotubes

    OpenAIRE

    Ando, Yoshinori; Zhao, Xinluo; Sugai, Toshiki; Kumar, Mukul

    2004-01-01

    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 ex...

  19. 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.

  20. Edge effects in finite elongated carbon nanotubes

    OpenAIRE

    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...

  1. 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.

  2. Simultaneous Determination of Parathion, Malathion, Diazinon, and Pirimiphos Methyl in Dried Medicinal Plants Using Solid-Phase Microextraction Fibre Coated with Single-Walled Carbon Nanotubes

    Science.gov (United States)

    Ahmadkhaniha, Reza; Samadi, Nasrin; Salimi, Mona; Sarkhail, Parisa; Rastkari, Noushin

    2012-01-01

    A reliable and sensitive headspace solid-phase microextraction gas chromatography-mass spectrometry method for simultaneous determination of different organophosphorus pesticides in dried medicinal plant samples is described. The analytes were extracted by single-walled carbon nanotubes as a new solid-phase microextraction adsorbent. The developed method showed good performance. For diazinon and pirimiphos methyl calibration, curves were linear (r 2 ≥ 0.993) over the concentration ranges from 1.5 to 300 ng g−1, and the limit of detection at signal-to-noise ratio of 3 was 0.3 ng g−1. For parathion and malathion, the linear range and limit of detection were 2.5–300 (r 2 ≥ 0.991) and 0.5 ng g−1, respectively. In addition, a comparative study between the single-walled carbon nanotubes and a commercial polydimethylsiloxane fibre for the determination of target analytes was carried out. Single-walled carbon nanotubes fibre showed higher extraction capacity, better thermal stability (over 350°C), and longer lifespan (over 250 times) than the commercial polydimethylsiloxane fibre. The developed method was successfully applied to determine target organophosphorus pesticides in real samples. PMID:22645439

  3. Simultaneous Determination of Parathion, Malathion, Diazinon, and Pirimiphos Methyl in Dried Medicinal Plants Using Solid-Phase Microextraction Fibre Coated with Single-Walled Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Reza Ahmadkhaniha

    2012-01-01

    Full Text Available A reliable and sensitive headspace solid-phase microextraction gas chromatography-mass spectrometry method for simultaneous determination of different organophosphorus pesticides in dried medicinal plant samples is described. The analytes were extracted by single-walled carbon nanotubes as a new solid-phase microextraction adsorbent. The developed method showed good performance. For diazinon and pirimiphos methyl calibration, curves were linear (r2≥0.993 over the concentration ranges from 1.5 to 300 ng g−1, and the limit of detection at signal-to-noise ratio of 3 was 0.3 ng g−1. For parathion and malathion, the linear range and limit of detection were 2.5–300 (r2≥0.991 and 0.5 ng g−1, respectively. In addition, a comparative study between the single-walled carbon nanotubes and a commercial polydimethylsiloxane fibre for the determination of target analytes was carried out. Single-walled carbon nanotubes fibre showed higher extraction capacity, better thermal stability (over 350∘C, and longer lifespan (over 250 times than the commercial polydimethylsiloxane fibre. The developed method was successfully applied to determine target organophosphorus pesticides in real samples.

  4. 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.

  5. 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...

  6. 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

  7. Ophthalmologial Applications of Carbon Nanotube Nanotechology

    Science.gov (United States)

    Loftus, David; Girten, Beverly (Technical Monitor)

    2002-01-01

    The development of an implantable device consisting of an array of carbon nanotubes on a silicon chip for restoration of vision in patients with macular degeneration and other retinal disorders is presented. The use of carbon nanotube bucky paper for retinal cell transplantation is proposed. This paper is in viewgraph form.

  8. 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.

  9. Epoxy-based carbon nanotubes reinforced composites

    CSIR Research Space (South Africa)

    Kesavan Pillai, Sreejarani

    2011-04-01

    Full Text Available developed strategy offering promising results is to reinforce epoxy matrices with nano-sized organic and inorganic particles such as carbon nanotubes (CNTs), carbon nanofibres (CNFs), nanoclays, metal oxide nanoparticles, etc. and make new materials...

  10. 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.

  11. 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

  12. Liquid surface model for carbon nanotube energetics

    DEFF Research Database (Denmark)

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

    2008-01-01

    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...... 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...... the calculated energies we determine the elastic properties of the single-wall carbon nanotubes (Young modulus, curvature constant) and perform a comparison with available experimental measurements and earlier theoretical predictions....

  13. Homogeneous CdTe quantum dots-carbon nanotubes heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Vieira, Kayo Oliveira [Grupo de Pesquisa em Química de Materiais – (GPQM), Departamento de Ciências Naturais, Universidade Federal de São João del-Rei, Campus Dom Bosco, Praça Dom Helvécio, 74, CEP 36301-160, São João del-Rei, MG (Brazil); Bettini, Jefferson [Laboratório Nacional de Nanotecnologia, Centro Nacional de Pesquisa em Energia e Materiais, CEP 13083-970, Campinas, SP (Brazil); Ferrari, Jefferson Luis [Grupo de Pesquisa em Química de Materiais – (GPQM), Departamento de Ciências Naturais, Universidade Federal de São João del-Rei, Campus Dom Bosco, Praça Dom Helvécio, 74, CEP 36301-160, São João del-Rei, MG (Brazil); Schiavon, Marco Antonio, E-mail: schiavon@ufsj.edu.br [Grupo de Pesquisa em Química de Materiais – (GPQM), Departamento de Ciências Naturais, Universidade Federal de São João del-Rei, Campus Dom Bosco, Praça Dom Helvécio, 74, CEP 36301-160, São João del-Rei, MG (Brazil)

    2015-01-15

    The development of homogeneous CdTe quantum dots-carbon nanotubes heterostructures based on electrostatic interactions has been investigated. We report a simple and reproducible non-covalent functionalization route that can be accomplished at room temperature, to prepare colloidal composites consisting of CdTe nanocrystals deposited onto multi-walled carbon nanotubes (MWCNTs) functionalized with a thin layer of polyelectrolytes by layer-by-layer technique. Specifically, physical adsorption of polyelectrolytes such as poly (4-styrene sulfonate) and poly (diallyldimethylammonium chloride) was used to deagglomerate and disperse MWCNTs, onto which we deposited CdTe quantum dots coated with mercaptopropionic acid (MPA), as surface ligand, via electrostatic interactions. Confirmation of the CdTe quantum dots/carbon nanotubes heterostructures was done by transmission and scanning electron microscopies (TEM and SEM), dynamic-light scattering (DLS) together with absorption, emission, Raman and infrared spectroscopies (UV–vis, PL, Raman and FT-IR). Almost complete quenching of the PL band of the CdTe quantum dots was observed after adsorption on the MWCNTs, presumably through efficient energy transfer process from photoexcited CdTe to MWCNTs. - Highlights: • Highly homogeneous CdTe-carbon nanotubes heterostructures were prepared. • Simple and reproducible non-covalent functionalization route. • CdTe nanocrystals homogeneously deposited onto multi-walled carbon nanotubes. • Efficient energy transfer process from photoexcited CdTe to MWCNTs.

  14. Investigation of growth dynamics of carbon nanotubes

    Directory of Open Access Journals (Sweden)

    Marianna V. Kharlamova

    2017-04-01

    Full Text Available The synthesis of single-walled carbon nanotubes (SWCNTs with defined properties is required for both fundamental investigations and practical applications. The revealing and thorough understanding of the growth mechanism of SWCNTs is the key to the synthesis of nanotubes with required properties. This paper reviews the current status of the research on the investigation of growth dynamics of carbon nanotubes. The review starts with the consideration of the peculiarities of the growth mechanism of carbon nanotubes. The physical and chemical states of the catalyst during the nanotube growth are discussed. The chirality selective growth of nanotubes is described. The main part of the review is dedicated to the analysis and systematization of the reported results on the investigation of growth dynamics of nanotubes. The studies on the revealing of the dependence of the growth rate of nanotubes on the synthesis parameters are reviewed. The correlation between the lifetime of catalyst and growth rate of nanotubes is discussed. The reports on the calculation of the activation energy of the nanotube growth are summarized. Finally, the growth properties of inner tubes inside SWCNTs are considered.

  15. Investigation of growth dynamics of carbon nanotubes

    Science.gov (United States)

    2017-01-01

    The synthesis of single-walled carbon nanotubes (SWCNTs) with defined properties is required for both fundamental investigations and practical applications. The revealing and thorough understanding of the growth mechanism of SWCNTs is the key to the synthesis of nanotubes with required properties. This paper reviews the current status of the research on the investigation of growth dynamics of carbon nanotubes. The review starts with the consideration of the peculiarities of the growth mechanism of carbon nanotubes. The physical and chemical states of the catalyst during the nanotube growth are discussed. The chirality selective growth of nanotubes is described. The main part of the review is dedicated to the analysis and systematization of the reported results on the investigation of growth dynamics of nanotubes. The studies on the revealing of the dependence of the growth rate of nanotubes on the synthesis parameters are reviewed. The correlation between the lifetime of catalyst and growth rate of nanotubes is discussed. The reports on the calculation of the activation energy of the nanotube growth are summarized. Finally, the growth properties of inner tubes inside SWCNTs are considered. PMID:28503394

  16. Cationic Carbon Nanotubes for Nucleic Acids Delivery

    OpenAIRE

    Battigelli, Alessia

    2012-01-01

    2010/2011 Carbon nanotubes (CNTs) are a new form of carbon discovered in the ’50/’60, but described at the atomic level only in 1991 by Iijima. CNTs are constituted by one or more rolled up graphene sheets and they can be classified in single-walled carbon nanotubes (SWCNTs) or multi-walled carbon nanotubes (MWCNTs). The peculiar properties of CNTs, characterized by their physical, chemical and mechanical properties, by their thermic conductivity and their large aspect ratio, rendered this...

  17. Simultaneous determination of polar and apolar compounds in environmental samples by a polyaniline/hydroxyl multi-walled carbon nanotubes composite-coated stir bar sorptive extraction coupled with high performance liquid chromatography.

    Science.gov (United States)

    Hu, Cong; He, Man; Chen, Beibei; Hu, Bin

    2015-05-15

    Developing novel coatings for stir bar sorptive extraction (SBSE) is essential for extending the application of SBSE. Herein, a polyaniline/hydroxyl multi-walled carbon nanotubes (PANi/MWCNTs-OH) composite-coated stir bar was prepared via the adhesion technique for the simultaneous extraction of polar and apolar compounds, and a novel method of PANi/MWCNTs-OH-coated SBSE coupled with high performance liquid chromatography-ultraviolet detection (HPLC-UV) was proposed. To test the extraction performance of PANi/MWCNTs-OH-coated stir bar, phenols, non-steroidal anti-inflammatory drugs, and polychlorinated biphenyls were selected as representatives for polar, semi-polar and apolar compounds, respectively. High enrichment factors (EFs) ranged from 20.4 to 60.4-fold (theoretical EF, 100-fold) for target analytes were achieved, indicating that the proposed method is applicable in simultaneous analysis of the compounds with different polarities. The prepared PANi/MWCNTs-OH-coated stir bar has a good preparation reproducibility and can be reused for 20 times. The limits of detection (LODs, S/N=3) were found to be in the range of 0.09-0.81μg/L. To validate the applicability, the proposed method was successfully applied to the analysis of eight target analytes in Yangtze River water after filtration and in the extract from sediment samples. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Carbon nanotubes for biomedical imaging: the recent advances.

    Science.gov (United States)

    Gong, Hua; Peng, Rui; Liu, Zhuang

    2013-12-01

    This article reviews the latest progresses regarding the applications of carbon nanotubes (CNTs), including single-walled carbon nanotubes (SWNTs) and multi-walled carbon nanotubes (MWNTs), as multifunctional nano-probes for biomedical imaging. Utilizing the intrinsic band-gap fluorescence of semi-conducting single-walled carbon nanotubes (SWNTs), fluorescence imaging in the near infrared II (NIR-II) region with enhanced tissue penetration and spatial resolution has shown great promise in recent years. Raman imaging based on the resonance Raman scattering of SWNTs has also been explored by a number of groups for in vitro and in vivo imaging of biological samples. The strong absorbance of CNTs in the NIR region can be used for photoacoustic imaging, and their photoacoustic signals can be dramatically enhanced by adding organic dyes, or coating with gold shells. Taking advantages of metal nanoparticle impurities attached to nanotubes, CNTs can also serve as a T2-contrast agent in magnetic resonance (MR) imaging. In addition, when labeled with radioactive isotopes, many groups have developed nuclear imaging with functionalized CNTs. Therefore CNTs are unique imaging probes with great potential in biomedical multimodal imaging. © 2013.

  19. Carbon nanotube woven textile photodetector

    Science.gov (United States)

    Zubair, Ahmed; Wang, Xuan; Mirri, Francesca; Tsentalovich, Dmitri E.; Fujimura, Naoki; Suzuki, Daichi; Soundarapandian, Karuppasamy P.; Kawano, Yukio; Pasquali, Matteo; Kono, Junichiro

    2018-01-01

    The increasing interest in mobile and wearable technology demands the enhancement of functionality of clothing through incorporation of sophisticated architectures of multifunctional materials. Flexible electronic and photonic devices based on organic materials have made impressive progress over the past decade, but higher performance, simpler fabrication, and most importantly, compatibility with woven technology are desired. Here we report on the development of a weaved, substrateless, and polarization-sensitive photodetector based on doping-engineered fibers of highly aligned carbon nanotubes. This room-temperature-operating, self-powered detector responds to radiation in an ultrabroad spectral range, from the ultraviolet to the terahertz, through the photothermoelectric effect, with a low noise-equivalent power (a few nW/Hz 1 /2) throughout the range and with a Z T -factor value that is twice as large as that of previously reported carbon nanotube-based photothermoelectric photodetectors. Particularly, we fabricated a ˜1 -m-long device consisting of tens of p+-p- junctions and weaved it into a shirt. This device demonstrated a collective photoresponse of the series-connected junctions under global illumination. The performance of the device did not show any sign of deterioration through 200 bending tests with a bending radius smaller than 100 μ m as well as standard washing and ironing cycles. This unconventional photodetector will find applications in wearable technology that require detection of electromagnetic radiation.

  20. Separation of Metallic and Semiconducting Carbon Nanotubes.

    Science.gov (United States)

    Tambraparni, Madhava B; Wang, Shiren

    2010-01-01

    Carbon nanotubes are currently the focus of intense interest due to their extraordinary properties. However, as-grown nanotubes exist as bundles of metallic and semiconducting. This hinders their widespread applications. Much progress has been made to overcome this limitation. Many separation methods have been investigated, including combination of physical, chemical, or biochemical methods. These methods have demonstrated their own advantages and limitations. This paper reviews recent patents progress made for the separation of metallic and semiconducting nanotubes.

  1. 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...... of nanotubes in presence of an interface with various substances, including air and water. Comparison with previous works is established whenever is possible....

  2. Carbon nanotube-based synthetic gecko tapes

    OpenAIRE

    Ge, Liehui; Sethi, Sunny; Ci, Lijie; Ajayan, Pulickel M.; Dhinojwala, Ali

    2007-01-01

    We have developed a synthetic gecko tape by transferring micropatterned carbon nanotube arrays onto flexible polymer tape based on the hierarchical structure found on the foot of a gecko lizard. The gecko tape can support a shear stress (36 N/cm2) nearly four times higher than the gecko foot and sticks to a variety of surfaces, including Teflon. Both the micrometer-size setae (replicated by nanotube bundles) and nanometer-size spatulas (individual nanotubes) are necessary to achieve macroscop...

  3. Carbon nanotubes: Sensor properties. A Review

    OpenAIRE

    Zaporotskova, Irina V.; Natalia P. Boroznina; Parkhomenko, Yuri N.; Kozhitov, Lev V.

    2017-01-01

    Recent publications dealing with dealing with the fabrication of gas and electrochemical biosensors based on carbon nanotubes have been reviewed. Experimental and theoretical data on the working principles of nanotubes have been presented. The main regularities of the structure, energy parameters and sensor properties of modified semiconducting systems on the basis of cabon nanotubes have been studied by analyzing the mechanisms of nanotubule interaction with functional groups (including carb...

  4. Combined antenna and localized plasmon resonance in Raman scattering from random arrays of silver-coated, vertically aligned multiwalled carbon nanotubes.

    Science.gov (United States)

    Dawson, P; Duenas, J A; Boyle, M G; Doherty, M D; Bell, S E J; Kern, A M; Martin, O J F; Teh, A-S; Teo, K B K; Milne, W I

    2011-02-09

    The electric field enhancement associated with detailed structure within novel optical antenna nanostructures is modeled using the surface integral equation technique in the context of surface-enhanced Raman scattering (SERS). The antennae comprise random arrays of vertically aligned, multiwalled carbon nanotubes dressed with highly granular Ag. Different types of "hot-spot" underpinning the SERS are identified, but contrasting characteristics are revealed. Those at the outer edges of the Ag grains are antenna driven with field enhancement amplified in antenna antinodes while intergrain hotspots are largely independent of antenna activity. Hot-spots between the tops of antennae leaning towards each other also appear to benefit from antenna amplification.

  5. Effect of Accelerated Thermal Ageing on the Selective Solar Thermal Harvesting Properties of Multiwall Carbon Nanotube/Nickel Oxide Nanocomposite Coatings

    Directory of Open Access Journals (Sweden)

    Kittessa T. Roro

    2012-01-01

    Full Text Available Varying amounts of dispersed multiwalled carbon nanotubes in NiO have been used to develop composites that absorb the solar energy very well but lose very little through emission. Determination of absorptance, αsol, and emissivity, εther, from such selective solar absorbers shows that the optimum efficiency of 71% can be attained when about 10 mg of MWCNTs are composited with NiO. One such absorber was subjected to thermal ageing tests. The performance criterion (PC limit for passing the test when simulated for 25 years is (−Δα+0.25Δε≤0.05. It was found that the typical absorber had a PC value of −0.01. This value is much better than the passing limit. Raman spectra of the typical absorber before and after the thermal ageing test showed a reduced intensity in the D and G bands of disordered and graphitic carbon, respectively but an enhancement of the NiO bands indicating loss of carbon atoms due to thermal ageing tests. Simple equations are derived determining the proportion of carbon atoms that are lost and the proportion of carbon atoms that remains in the absorber; both of these are in agreement with the original carbon composition before the thermal ageing test. It is reported that the typical absorber will retain 63% of the carbon after 25 years.

  6. 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. © 2011 American Chemical Society

  7. High surface area silicon carbide-coated carbon aerogel

    Science.gov (United States)

    Worsley, Marcus A; Kuntz, Joshua D; Baumann, Theodore F; Satcher, Jr, Joe H

    2014-01-14

    A metal oxide-carbon composite includes a carbon aerogel with an oxide overcoat. The metal oxide-carbon composite is made by providing a carbon aerogel, immersing the carbon aerogel in a metal oxide sol under a vacuum, raising the carbon aerogel with the metal oxide sol to atmospheric pressure, curing the carbon aerogel with the metal oxide sol at room temperature, and drying the carbon aerogel with the metal oxide sol to produce the metal oxide-carbon composite. The step of providing a carbon aerogel can provide an activated carbon aerogel or provide a carbon aerogel with carbon nanotubes that make the carbon aerogel mechanically robust. Carbon aerogels can be coated with sol-gel silica and the silica can be converted to silicone carbide, improved the thermal stability of the carbon aerogel.

  8. Methods for producing reinforced carbon nanotubes

    Science.gov (United States)

    Ren, Zhifen [Newton, MA; Wen, Jian Guo [Newton, MA; Lao, Jing Y [Chestnut Hill, MA; Li, Wenzhi [Brookline, MA

    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.

  9. Carbon nanotube fiber spun from wetted ribbon

    Energy Technology Data Exchange (ETDEWEB)

    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.

  10. Titanium dioxide, single-walled carbon nanotube composites

    Science.gov (United States)

    Yao, Yuan; Li, Gonghu; Gray, Kimberly; Lueptow, Richard M.

    2015-07-14

    The present invention provides titanium dioxide/single-walled carbon nanotube composites (TiO.sub.2/SWCNTs), articles of manufacture, and methods of making and using such composites. In certain embodiments, the present invention provides membrane filters and ceramic articles that are coated with TiO.sub.2/SWCNT composite material. In other embodiments, the present invention provides methods of using TiO.sub.2/SWCNT composite material to purify a sample, such as a water or air sample.

  11. Covalent enzyme immobilization onto carbon nanotubes using a membrane reactor

    Science.gov (United States)

    Voicu, Stefan Ioan; Nechifor, Aurelia Cristina; Gales, Ovidiu; Nechifor, Gheorghe

    2011-05-01

    Composite porous polysulfone-carbon nanotubes membranes were prepared by dispersing carbon nanotubes into a polysulfone solution followed by the membrane formation by phase inversion-immersion precipitation technique. The carbon nanotubes with amino groups on surface were functionalized with different enzymes (carbonic anhydrase, invertase, diastase) using cyanuric chloride as linker between enzyme and carbon nanotube. The composite membrane was used as a membrane reactor for a better dispersion of carbon nanotubes and access to reaction centers. The membrane also facilitates the transport of enzymes to active carbon nanotubes centers for functionalization (amino groups). The functionalized carbon nanotubes are isolated by dissolving the membranes after the end of reaction. Carbon nanotubes with covalent immobilized enzymes are used for biosensors fabrications. The obtained membranes were characterized by Scanning Electron Microscopy, Thermal analysis, FT-IR Spectroscopy, Nuclear Magnetic Resonance, and functionalized carbon nanotubes were characterized by FT-IR spectroscopy.

  12. In Vivo Toxicity Assessment of Occupational Components of the Carbon Nanotube Life Cycle To Provide Context to Potential Health Effects.

    Science.gov (United States)

    Bishop, Lindsey; Cena, Lorenzo; Orandle, Marlene; Yanamala, Naveena; Dahm, Matthew M; Birch, M Eileen; Evans, Douglas E; Kodali, Vamsi K; Eye, Tracy; Battelli, Lori; Zeidler-Erdely, Patti C; Casuccio, Gary; Bunker, Kristin; Lupoi, Jason S; Lersch, Traci L; Stefaniak, Aleksandr B; Sager, Tina; Afshari, Aliakbar; Schwegler-Berry, Diane; Friend, Sherri; Kang, Jonathan; Siegrist, Katelyn J; Mitchell, Constance A; Lowry, David T; Kashon, Michael L; Mercer, Robert R; Geraci, Charles L; Schubauer-Berigan, Mary K; Sargent, Linda M; Erdely, Aaron

    2017-09-26

    Pulmonary toxicity studies on carbon nanotubes focus primarily on as-produced materials and rarely are guided by a life cycle perspective or integration with exposure assessment. Understanding toxicity beyond the as-produced, or pure native material, is critical, due to modifications needed to overcome barriers to commercialization of applications. In the first series of studies, the toxicity of as-produced carbon nanotubes and their polymer-coated counterparts was evaluated in reference to exposure assessment, material characterization, and stability of the polymer coating in biological fluids. The second series of studies examined the toxicity of aerosols generated from sanding polymer-coated carbon-nanotube-embedded or neat composites. Postproduction modification by polymer coating did not enhance pulmonary injury, inflammation, and pathology or in vitro genotoxicity of as-produced carbon nanotubes, and for a particular coating, toxicity was significantly attenuated. The aerosols generated from sanding composites embedded with polymer-coated carbon nanotubes contained no evidence of free nanotubes. The percent weight incorporation of polymer-coated carbon nanotubes, 0.15% or 3% by mass, and composite matrix utilized altered the particle size distribution and, in certain circumstances, influenced acute in vivo toxicity. Our study provides perspective that, while the number of workers and consumers increases along the life cycle, toxicity and/or potential for exposure to the as-produced material may greatly diminish.

  13. Strongly correlated electron behavior in carbon nanotubes

    Directory of Open Access Journals (Sweden)

    Hone James

    2012-03-01

    Full Text Available One dimensional systems offer a fascinating platform for investigating and understanding the collective and many-body behavior of interacting electron systems. We report low-temperature transport experiments on carbon nanotubes, which are archetypal one-dimensional systems that have either semiconducting or metallic band structure depending on their radius and chirality. Semiconducting nanotubes at low densities exhibit Wigner crystal behavior, while nominally metallic nanotubes are observed to have an energy gap at half filling, consistent with theories of a Mott insulating state in nanotubes. Our results demonstrate nanotubes’ promise for studying a variety of tunable correlated electron phenomena in one dimension.

  14. 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...

  15. Effect of Novel Quercetin Titanium Dioxide-Decorated Multi-Walled Carbon Nanotubes Nanocomposite on Bacillus subtilis Biofilm Development

    Directory of Open Access Journals (Sweden)

    Diana S. Raie

    2018-01-01

    Full Text Available The present work was targeted to design a surface against cell seeding and adhering of bacteria, Bacillus subtilis. A multi-walled carbon nanotube/titanium dioxide nano-power was produced via simple mixing of carbon nanotube and titanium dioxide nanoparticles during the sol-gel process followed by heat treatment. Successfully, quercetin was immobilized on the nanocomposite via physical adsorption to form a quercetin/multi-walled carbon nanotube/titanium dioxide nanocomposite. The adhesion of bacteria on the coated-slides was verified after 24 h using confocal laser-scanning microscopy. Results indicated that the quercetin/multi-walled carbon nanotube/titanium dioxide nanocomposite had more negativity and higher recovery by glass surfaces than its counterpart. Moreover, coating surfaces with the quercetin-modified nanocomposite lowered both hydrophilicity and surface-attached bacteria compared to surfaces coated with the multi-walled carbon nanotubes/titanium dioxide nanocomposite.

  16. Channeling of protons through carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Borka, D; Petrovic, S; Neskovic, N [Laboratory of Physics (010), Vinca Institute of Nuclear Sciences, P. O. Box 522, 11001 Belgrade (Serbia); Mowbray, D J; Miskovic, Z L [Department of Applied Mathematics, University of Waterloo, Waterloo, Ontario, N2L3G1 (Canada)], E-mail: dusborka@vin.bg.ac.yu

    2008-10-01

    We investigate how dynamic polarization of carbon valence electrons influences both the angular and spatial distributions of protons channeled in a (11, 9) single-wall carbon nanotube placed in vacuum and in different dielectric media. Proton speeds between 3 and 10 a.u., corresponding to energies of 0.223 and 2.49 MeV, are chosen with the nanotube length varied between 0.1 and 1 {mu}m. In all performed calculations we describe the interaction between proton and carbon atoms on the nanotube wall using the Doyle-Turner potential. The image force on a proton is calculated using a two-dimensional hydrodynamic model for the dynamic response of the nanotube valence electrons and the dielectric media surrounding the nanotube. The angular distributions of channeled protons are generated using a computer simulation method which solves the proton equations of motion in the transverse plane numerically. The best level of ordering and straightening of carbon nanotube arrays is often achieved when they are grown in a dielectric matrix. Consequently, we investigate here how the dynamic polarization of carbon valence electrons in the presence of various surrounding dielectric media affects the angular distributions of protons channeled through (11, 9) single-wall carbon nanotubes. Our analysis shows that the inclusion of the image interaction, gives rise to a number of rainbow maxima in the corresponding angular and spatial distribution. Our analysis shows that the presence of dielectric media surrounding the nanotube influences the positions and appearance of rainbows in the corresponding angular and spatial distributions. In addition, we analyze the possibility of production of nano-sized beams by carbon nanotubes.

  17. 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.

  18. 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.

  19. 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.

  20. 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. PMID:23091380

  1. 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.

  2. Photonics based on carbon nanotubes.

    Science.gov (United States)

    Gu, Qingyuan; Gicquel-Guézo, Maud; Loualiche, Slimane; Pouliquen, Julie Le; Batte, Thomas; Folliot, Hervé; Dehaese, Olivier; Grillot, Frederic; Battie, Yann; Loiseau, Annick; Liang, Baolai; Huffaker, Diana

    2013-06-26

    Among direct-bandgap semiconducting nanomaterials, single-walled carbon nanotubes (SWCNT) exhibit strong quasi-one-dimensional excitonic optical properties, which confer them a great potential for their integration in future photonics devices as an alternative solution to conventional inorganic semiconductors. In this paper, we will highlight SWCNT optical properties for passive as well as active applications in future optical networking. For passive applications, we directly compare the efficiency and power consumption of saturable absorbers (SAs) based on SWCNT with SA based on conventional multiple quantum wells. For active applications, exceptional photoluminescence properties of SWCNT, such as excellent light-emission stabilities with temperature and excitation power, hold these nanometer-scale materials as prime candidates for future active photonics devices with superior performances.

  3. Carbon nanotubes based vacuum gauge

    Science.gov (United States)

    Rudyk, N. N.; Il’in, O. I.; Il’ina, M. V.; Fedotov, A. A.; Klimin, V. S.; Ageev, O. A.

    2017-11-01

    We have created an ionization type Vacuum gauge with sensor element based on an array of vertically aligned carbon nanotubes. Obtained asymmetrical current-voltage characteristics at different voltage polarity on the electrode with the CNTs. It was found that when applying a negative potential on an electrode with the CNTs, the current in the gap is higher than at a positive potential. In the pressure range of 1 ÷ 103 Torr vacuum gauge sensitivity was 6 mV/Torr (at a current of 4.5·10-5 A) and in the range of 10-5 ÷ 1 Torr was 10 mV/Torr (at a current of 1.3·10-5 A). It is shown that the energy efficiency of vacuum gauge can be increased in the case where electrode with CNT operates as an emitter of electrons.

  4. Occupational Exposure to Carbon Nanotubes and Nanofibers

    Science.gov (United States)

    ... metal oxides, nanotubes, nanowires, quantum dots, and carbon fullerenes (buckyballs), among others. Early scientific studies have indicated ... to minimize worker exposure. This NIOSH CIB, (1) reviews the animal and other toxicological data relevant to ...

  5. Carbon nanotubes dispersed polymer nanocomposites: mechanical ...

    Indian Academy of Sciences (India)

    CNT composite showed that the rough ... data storage, sensors, and biomedical applications [9]. The polydimethylsiloxane (PDMS) and ... that undergoes big distortions without deteriorations [15,16]. The carbon nanotubes (CNTs) consist of ...

  6. Fermentation based carbon nanotube multifunctional bionic composites

    National Research Council Canada - National Science Library

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

    2016-01-01

    .... 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...

  7. 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.

  8. Carbon nanotube polymer composition and devices

    Science.gov (United States)

    Liu, Gao [Oakland, CA; Johnson, Stephen [Richmond, CA; Kerr, John B [Oakland, CA; Minor, Andrew M [El Cerrito, CA; Mao, Samuel S [Castro Valley, CA

    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.

  9. 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).

  10. 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...

  11. Multiwalled Carbon Nanotubes Reinforced Polypropylene Composite Material

    Directory of Open Access Journals (Sweden)

    Juan Li

    2017-01-01

    Full Text Available Polypropylene (PP composites reinforced with multiwalled carbon nanotubes (MWNTs were prepared by using twin screw extruder. The experimental results showed that with the increasing amount of MWNTs the elongation at break decreased whereas the tensile strength, bending strength, and impact strength increased. By using scanning electron microscope (SEM, we find that the hydroxyl-modified carbon nanotube has better dispersion performance in PP and better mechanical properties.

  12. Carbon nanotube temperature and pressure sensors

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, Ilia N.; Geohegan, David B.

    2017-09-12

    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.

  13. Carbon nanotube temperature and pressure sensors

    Science.gov (United States)

    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.

  14. Carbon nanotubes as near infrared laser susceptors

    OpenAIRE

    Bahrami, Amir

    2011-01-01

    The coupling efficiency of carbon nanotubes with near infrared laser radiation at 940nm wavelength was investigated. Nanotubes treated with different post processing methods were irradiated at different laser power intensities as dry samples and suspensions in water or ethanol. The interaction with the laser beam was measured and quantified based on the temperature increase in the samples as well as the amount of energy transmitted through them. Parallel experiments using carbon black reveale...

  15. 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.

  16. Single electron-ics with carbon nanotubes

    OpenAIRE

    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 real-time charge readout and precise tuning of the tunnel barriers of the quantum dot. The second part of this thesis describes the realization of exceptionally clean Carbon Nanotube quantum dots....

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Method for manufacturing high quality carbon nanotubes

    Science.gov (United States)

    Benavides, Jeanette M. (Inventor)

    2006-01-01

    A non-catalytic process for the production of carbon nanotubes includes supplying an electric current to a carbon anode and a carbon cathode which have been securely positioned in the open atmosphere with a gap between them. The electric current creates an electric arc between the carbon anode and the carbon cathode, which causes carbon to be vaporized from the carbon anode and a carbonaceous residue to be deposited on the carbon cathode. Inert gas is pumped into the gap to flush out oxygen, thereby preventing interference with the vaporization of carbon from the anode and preventing oxidation of the carbonaceous residue being deposited on the cathode. The anode and cathode are cooled while electric current is being supplied thereto. When the supply of electric current is terminated, the carbonaceous residue is removed from the cathode and is purified to yield carbon nanotubes.

  2. Carbon Nanotube Areas - Printed on Textile and Paper Substrates

    Directory of Open Access Journals (Sweden)

    Arved C. Hubler

    2011-06-01

    Full Text Available Mass printing processes are the key technology to produce mass products to the point of one-disposable. Carbon nanotube (CNT based structures were prepared by flexographic printing using multi-walled carbon nanotube (MWCNT dispersions in water. The carbon nanotubes were applied to a textile substrate made of polyester and polyamide microfilaments and to both-side coated paper to produce electrically conductive layers that can be used, for example, as heating elements. Carbon nanotube layers with sheet resistivity ranging from 0.12 to 3.00 kΩ/sq were obtained. The ratio of radiation power PS (determined according to the Stefan-Boltzmann law of the printed layers to the electrical power spent, represents the efficiency of the system. The samples on textile substrate with a surface temperature of 169°C have an efficiency of 25%, the paper samples with a surface temperature of 93°C have an efficiency of about 15%.

  3. Method for nano-pumping using carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Insepov, Zeke [Darien, IL; Hassanein, Ahmed [Bolingbrook, IL

    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.

  4. Quantum conductance of a helically coiled carbon nanotube

    Directory of Open Access Journals (Sweden)

    Wengang Lu

    2005-01-01

    Full Text Available Using a π-orbital tight-binding model, we investigate the transport properties of a coiled carbon nanotube (also called carbon nanotube spring, which we construct by connecting carbon nanotubes periodically in three-dimensional (3D space. The conductance is quantized due to the translational symmetry in the coiled direction. However, the conductance behaviors differ greatly from those of pristine metallic carbon nanotubes but similar to those of carbon nanotube superlattices. We explain that conductance behaviors of the coiled carbon nanotube.

  5. Single-Walled Carbon Nanotubes as Fluorescence Biosensors for Pathogen Recognition in Water Systems

    Directory of Open Access Journals (Sweden)

    Venkata K. K. Upadhyayula

    2008-01-01

    Full Text Available The possibility of using single-walled carbon nanotubes (SWCNTs aggregates as fluorescence sensors for pathogen recognition in drinking water treatment applications has been studied. Batch adsorption study is conducted to adsorb large concentrations of Staphylococcus aureus aureus SH 1000 and Escherichia coli pKV-11 on single-walled carbon nanotubes. Subsequently the immobilized bacteria are detected with confocal microscopy by coating the nanotubes with fluorescence emitting antibodies. The Freundlich adsorption equilibrium constant (k for S.aureus and E.coli determined from batch adsorption study was found to be 9×108 and 2×108 ml/g, respectively. The visualization of bacterial cells adsorbed on fluorescently modified carbon nanotubes is also clearly seen. The results indicate that hydrophobic single-walled carbon nanotubes have excellent bacterial adsorption capacity and fluorescent detection capability. This is an important advancement in designing fluorescence biosensors for pathogen recognition in water systems.

  6. Carbon nanotube stationary phases for microchip electrochromatography

    DEFF Research Database (Denmark)

    Mogensen, Klaus Bo; Bøggild, Peter; Kutter, Jörg Peter

    The use of nanomaterials in separation science has increased rapidly in the last decade. The reason for this is to take advantage of the unique properties of these materials, such as a very high surface-to-volume ratio and favourable sorbent behaviour. Carbon nanostructures, such as carbon......, microfluidic devices with microfabricated carbon nanotube columns for electrochromatographic separations will be presented. The electrically conductive carbon nanotube layer has been patterned into hexoganol micropillars in order to support electroosmotic flow without forming gas bubbles from electrolysis...

  7. Synthesis of single wall carbon nanotubes from a lamellar type ...

    Indian Academy of Sciences (India)

    Wintec

    walled nanotubes. These nanotubes are applicable to store more hydrogen. Keywords. AlPO4-L; single wall carbon nanotubes. 1. Introduction. Carbon nanotubes (Iijima 1991) are nano-scale structures formed by self assembly. They possess excellent chemical and physical properties (Rodney and Donald 1995; Chen.

  8. 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.

  9. Enhanced graphitization of carbon around carbon nanotubes during the formation of carbon nanotube/graphite composites by pyrolysis of carbon nanotube/polyaniline composites.

    Science.gov (United States)

    Nam, Dong Hoon; Cha, Seung Il; Jeong, Yong Jin; Hong, Soon Hyung

    2013-11-01

    The carbon nanotubes (CNTs) are actively applied to the reinforcements for composite materials during last decade. One of the attempts is development of CNT/Carbon composites. Although there are some reports on the enhancement of mechanical properties by addition of CNTs in carbon or carbon fiber, it is far below the expectation. Considering the microstructure of carbon materials such as carbon fiber, the properties of them can be modified and enhanced by control of graphitization and alignment of graphene planes. In this study, enhanced graphitization of carbon has been observed the vicinity of CNTs during the pyrolysis of CNT/Polyaniline composites. As a result, novel types of composite, consisting of treading CNTs and coated graphite, can be fabricated. High-resolution transmission electron microscopy revealed a specific orientation relationship between the graphene layers and the CNTs, with an angle of 110 degrees between the layers and the CNT axis. The possibility of graphene alignment control in the carbon by the addition of CNTs is demonstrated.

  10. Quasi Solid-State Dye-Sensitized Solar Cell Incorporating Highly Conducting Polythiophene-Coated Carbon Nanotube Composites in Ionic Liquid

    Directory of Open Access Journals (Sweden)

    Mohammad Rezaul Karim

    2011-01-01

    Full Text Available Conducting polythiophene (PTh composites with the host filler multiwalled carbon nanotube (MWNT have been used, for the first time, in the dye-sensitized solar cells (DSCs. A quasi solid-state DSCs with the hybrid MWNT-PTh composites, an ionic liquid of 1-methyl-3-propyl imidazolium iodide (PMII, was placed between the dye-sensitized porous TiO2 and the Pt counter electrode without adding iodine and higher cell efficiency (4.76% was achieved, as compared to that containing bare PMII (0.29%. The MWNT-PTh nanoparticles are exploited as the extended electron transfer materials and serve simultaneously as catalyst for the electrochemical reduction of I−3.

  11. Preparation of carbon-coated TiO{sub 2} nanostructures for lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sang-Jun [Materials Research Center for Energy and Green Technology, Andong National University, Andong, Gyungbuk 760-745 (Korea, Republic of); Kim, Hansu [Department of Energy Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Kim, Young-Jun [Advanced Battery Research Center, Korea Electronics Technology Institute, Seongnam, Gyeonggi 463-816 (Korea, Republic of); Lee, Hyukjae, E-mail: hlee@andong.ac.kr [Materials Research Center for Energy and Green Technology, Andong National University, Andong, Gyungbuk 760-745 (Korea, Republic of)

    2011-06-01

    Highlights: > We prepare carbon-coated TiO{sub 2} nanotubes/nanowires by one-pot hydrothermal method. > Carbon coating increases electronic conductivity at higher calcination temperatures. > Carbon coating suppresses the agglomeration of nanotubes at lower calcination temperatures. - Abstract: Carbon-coated TiO{sub 2} one-dimensional nanostructures are synthesized by hydrothermal reaction followed by post-calcination at various temperatures. Post-calcination induces crystallization of TiO{sub 2} and the complete crystallization of anatase phase is observed at 600 deg. C of the calcination temperature. Carbon-coated TiO{sub 2} nanostructures show relatively poor crystallinity as compared with the pristine counterparts, but their lithiation capacity and high rate capability are improved throughout all calcination temperatures. The coated carbon suppresses severe agglomeration of TiO{sub 2} nanotubes which allows easy access of Li-ions and electrons to the whole surface of primary nanotubes, leading to the better lithiation performance. Higher calcination temperatures cause excessive growth of nanotube walls, leading to the collapse of tubular morphology and deterioration of lithiation performance. At 700 deg. C of the calcination temperature, the enhanced electronic conductivity from the graphitization of the coated carbon seems to be the main reason for the improved capacity of TiO{sub 2} nanowires.

  12. Processing and Characterization of Carbon Nanotube Composites

    Science.gov (United States)

    Can, Roberto J.; Grimsley, Brian W.; Czabaj, Michael W.; Siochi, Emilie J.; Hull, Brandon

    2014-01-01

    Recent advances in the synthesis of large-scale quantities of carbon nanotubes (CNT) have provided the opportunity to study the mechanical properties of polymer matrix composites using these novel materials as reinforcement. Nanocomp Technologies, Inc. currently supplies large sheets with dimensions up to 122 cm x 244 cm containing both single-wall and few-wall CNTs. The tubes are approximately 1 mm in length with diameters ranging from 8 to 12 nm. In the present study being conducted at NASA Langley Research Center (LaRC), single and multiple layers of CNT sheets were infused or coated with various polymer solutions that included commercial toughened-epoxies and bismaleimides, as well as a LaRC developed polyimide. The resulting CNT composites were tested in tension using a modified version of ASTM D882-12 to determine their strength and modulus values. The effects of solvent treatment and mechanical elongation/alignment of the CNT sheets on the tensile performance of the composite were determined. Thin composites (around 50 wt% CNT) fabricated from acetone condensed and elongated CNT sheets with either a BMI or polyimide resin solution exhibited specific tensile moduli approaching that of toughened epoxy/ IM7 carbon fiber unidirectional composites.

  13. Acrylonitrile, an advantageous precursor to synthesize nitrogen doped carbon nanotubes

    Science.gov (United States)

    Aguilar-Elguézabal, A.; Román-Aguirre, M.; De la Torre, L.; Zaragoza, E. A.

    2017-05-01

    The nitrogen doped carbon nanotubes present specific characteristics that offer better performance than pure carbon nanotubes for application like biomedicine, hydrogen adsorption and electrocataytic devices. This work present a simple method to obtain well-aligned nitrogen doped multi wall carbon nanotubes, which present open channels with diameter around 50 nm. These carbon nanotubes are obtained using acrylonitrile as carbon and nitrogen source, which offers some advantages on the use of other precursors like ammonia, pyridine, benzylamine, acetonitrile or melamine.

  14. Carbon nanotube and CdSe nanobelt Schottky junction solar cells.

    Science.gov (United States)

    Zhang, Luhui; Jia, Yi; Wang, Shanshan; Li, Zhen; Ji, Chunyan; Wei, Jinquan; Zhu, Hongwei; Wang, Kunlin; Wu, Dehai; Shi, Enzheng; Fang, Ying; Cao, Anyuan

    2010-09-08

    Developing nanostructure junctions is a general and effective way for making photovoltaics. We report Schottky junction solar cells by coating carbon nanotube films on individual CdSe nanobelts with open-circuit voltages of 0.5 to 0.6 V and modest power-conversion efficiencies (0.45-0.72%) under AM 1.5G, 100 mW/cm(2) light condition. In our planar device structure, the CdSe nanobelt serves as a flat substrate to sustain a network of nanotubes, while the nanotube film forms Shottky junction with the underlying nanobelt at their interface and also makes a transparent electrode for the device. The nanotube-on-nanobelt solar cells can work either in front (nanotube side) or back (nanobelt side) illumination with stable performance in air. Our results demonstrate a promising way to develop large-area solar cells based on thin films of carbon nanotubes and semiconducting nanostructures.

  15. Photocatalysis-assisted water filtration: Using TiO{sub 2}-coated vertically aligned multi-walled carbon nanotube array for removal of Escherichia coli O157:H7

    Energy Technology Data Exchange (ETDEWEB)

    Oza, Goldie; Pandey, Sunil; Gupta, Arvind; Shinde, Sachin; Mewada, Ashmi [N.S. N. Research Centre for Nanotechnology and Bionanotechnology, Jambhul Phata, Kalyan-Badlapur Road, Ambernath (W) 421505, Maharashtra (India); Jagadale, Pravin [DISAT — Department of Applied Science and Technology, Carbon group, Politecnico di Torino (Italy); Sharon, Maheshwar [N.S. N. Research Centre for Nanotechnology and Bionanotechnology, Jambhul Phata, Kalyan-Badlapur Road, Ambernath (W) 421505, Maharashtra (India); Sharon, Madhuri, E-mail: sharonmadhuri@gmail.com [N.S. N. Research Centre for Nanotechnology and Bionanotechnology, Jambhul Phata, Kalyan-Badlapur Road, Ambernath (W) 421505, Maharashtra (India)

    2013-10-01

    A porous ceramic was coated with vertically aligned multi-walled carbon nanotubes (MWCNTs) by spray pyrolysis. Titanium dioxide (TiO{sub 2}) nanoparticles were then coated onto this densely aligned MWCNT. The presence of TiO{sub 2}/MWCNT interfacial arrays was confirmed by X-ray diffraction (XRD), scanning electron microscope–energy dispersive analysis of X-ray (SEM–EDAX) and transmission electron microscope (TEM). This is a novel report in which water loaded with a most dreadful enterohemorrhagic pathogenic strain of Escherichia coli O157:H7 was filtered through TiO{sub 2}/MWCNT coated porous ceramic filter and then analysed. Bacterial removal performance was found to be significantly lower in control i.e. plain porous ceramic (P < 0.05) as compared to TiO{sub 2}/MWCNT coated ceramic. The photocatalytic killing rate constant for TiO{sub 2}-ceramic and MWCNT/TiO{sub 2}-ceramic under fluorescent light was found be 1.45 × 10{sup −2} min{sup −1} and 2.23 × 10{sup −2} min{sup −1} respectively. Further, when I–V characteristics were performed for TiO{sub 2}/MWCNT composite, it was corroborated that the current under light irradiation is comparatively higher than that in dark, thus proving it to be photocatalytically efficient system. The enhanced photocatalysis may be a contribution of increased surface area and charge transfer rate as a consequence of aligned MWCNT network. - Highlights: • Coating of vertically aligned MWCNT on ceramic candle filter • Surface orchestration of TiO{sub 2} on MWCNT arrays • I–V characteristic studies are performed under dark and illumination. • Photocatalytic efficiency of TiO{sub 2}/MWCNT arrays is determined using E. coli O157:H7. • Proposed a mechanism of bacterial killing due to free radical formation.

  16. 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.

  17. 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.

  18. Field emission properties of the graphenated carbon nanotube electrode

    Energy Technology Data Exchange (ETDEWEB)

    Zanin, H., E-mail: hudson.zanin@bristol.ac.uk [School of Chemistry, University of Bristol, Bristol BS8 1TS (United Kingdom); Faculdade de Engenharia Elétrica e Computação, Departamento de Semicondutores, Instrumentos e Fotônica, Universidade Estadual de Campinas, UNICAMP, Av. Albert Einstein N. 400, CEP 13 083-852 Campinas, São Paulo (Brazil); Ceragioli, H.J.; Peterlevitz, A.C.; Baranauskas, Vitor [Faculdade de Engenharia Elétrica e Computação, Departamento de Semicondutores, Instrumentos e Fotônica, Universidade Estadual de Campinas, UNICAMP, Av. Albert Einstein N. 400, CEP 13 083-852 Campinas, São Paulo (Brazil); Marciano, F.R.; Lobo, A.O. [Laboratory of Biomedical Nanotechnology/Institute of Research and Development at UNIVAP, Av. Shishima Hifumi, 2911, CEP 12244-000 Sao Jose dos Campos, SP (Brazil)

    2015-01-01

    Graphical abstract: - Highlights: • Facile method to prepare graphenated carbon nanotubes (g-CNTs). • The electric field emission behaviour of g-CNTs was studied. • g-CNTs show better emission current stability than non-graphenated CNTs. - Abstract: Reduced graphene oxide-coated carbon nanotubes (RGO-CNT) electrodes have been prepared by hot filament chemical vapour deposition system in one-step growth process. We studied RGO-CNT electrodes behaviour as cold cathode in field emission test. Our results show that RGO-CNT retain the low threshold voltage typical of CNTs, but with greatly improved emission current stability. The field emission enhancement value is significantly higher than that expected being caused by geometric effect (height divided by the radius of nanotube). This suggested that the field emission of this hybrid structure is not only from a single tip, but eventually it is from several tips with contribution of graphene nanosheets at CNT's walls. This phenomenon explains why the graphenated carbon nanotubes do not burn out as quickly as CNT does until emission ceases completely. These preliminaries results make nanocarbon materials good candidates for applications as electron sources for several devices.

  19. Selective Functionalization of Carbon Nanotubes: Part II

    Science.gov (United States)

    Meyyappan, Meyya; Khare, Bishun

    2010-01-01

    An alternative method of low-temperature plasma functionalization of carbon nanotubes provides for the simultaneous attachment of molecular groups of multiple (typically two or three) different species or different mixtures of species to carbon nanotubes at different locations within the same apparatus. This method is based on similar principles, and involves the use of mostly the same basic apparatus, as those of the methods described in "Low-Temperature Plasma Functionalization of Carbon Nanotubes" (ARC-14661-1), NASA Tech Briefs, Vol. 28, No. 5 (May 2004), page 45. The figure schematically depicts the basic apparatus used in the aforementioned method, with emphasis on features that distinguish the present alternative method from the other. In this method, one exploits the fact that the composition of the deposition plasma changes as the plasma flows from its source in the precursor chamber toward the nanotubes in the target chamber. As a result, carbon nanotubes mounted in the target chamber at different flow distances (d1, d2, d3 . . .) from the precursor chamber become functionalized with different species or different mixtures of species. In one series of experiments to demonstrate this method, N2 was used as the precursor gas. After the functionalization process, the carbon nanotubes from three different positions in the target chamber were examined by Fourier-transform infrared spectroscopy to identify the molecular groups that had become attached. On carbon nanotubes from d1 = 1 cm, the attached molecular groups were found to be predominantly C-N and C=N. On carbon nanotubes from d2 = 2.5 cm, the attached molecular groups were found to be predominantly C-(NH)2 and/or C=NH2. (The H2 was believed to originate as residual hydrogen present in the nanotubes.) On carbon nanotubes from d3 = 7 cm no functionalization could be detected - perhaps, it was conjectured, because this distance is downstream of the plasma source, all of the free ions and free radicals of

  20. 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.

  1. Co-TPP functionalized carbon nanotube composites for detection of ...

    Indian Academy of Sciences (India)

    Keywords. Electrical properties; nanostructure materials; porphyrin functionalized carbon nanotubes; sensor for chlorobenzene and nitrobenzene vapour. Abstract. We report preparation of nanocomposites by non-covalent functionalization of carbon nanotubes (CNTs) with metal-tetraphenylporphyrins (M-TPP). Fourier ...

  2. 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.

  3. 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.

  4. 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.

  5. 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 ...

  6. 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.

  7. Liquid crystalline order of carbon nanotubes

    Science.gov (United States)

    Georgiev, Georgi; Ahlawat, Aditya; Mulkern, Brian; Doyle, Robert; Mongeau, Jennifer; Ogilvie, Alex

    2007-03-01

    Topological defects formed during phase transitions in liquid crystals provide a direct proof of the standard Cosmological model and are direct links to the Early Universe. On the other hand in Nanotechnology, carbon nanotubes can be manipulated and oriented directly by changing the liquid crystalline state of the nanotubes, in combination with organic liquid crystals. Currently there are no nano-assemblers, which makes the liquid crystal state of the nanotubes, one of the few ways of controlling them. We show the design of a fast and efficient polarized light ellipsometric system (a new modification of previous optical systems) that can provide fast quantitative real time measurements in two dimensions of the formation of topological defects in liquid crystals during phase transitions in lab settings. Our aim is to provide fundamental information about the formation of optically anisotropic structures in liquid crystals and the orientation of carbon nanotubes in electric field.

  8. 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. (c) 2010 Elsevier Ltd. All rights reserved.

  9. Agglomeration defects on irradiated carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Steini Moura, Cassio [Faculty of Physics, Pontificia Universidade Catolica do Rio Grande do Sul, 90619-900, Porto Alegre, RS (Brazil); Balzaretti, Naira Maria; Amaral, Livio [Institute of Physics, Universidade Federal do Rio Grande do Sul, C.P.: 15051, 91501-070, Porto Alegre, RS (Brazil); Gribel Lacerda, Rodrigo; Pimenta, Marcos A. [Universidade Federal de Minas Gerais, C.P.: 702, 31270-901, Belo Horizonte, MG (Brazil)

    2012-03-15

    Aligned carbon nanotubes (CNT) were irradiated in the longitudinal and perpendicular directions, with low energy carbon and helium ions in order to observe the formation of defects in the atomic structure. Analysis through Raman spectroscopy and scanning electron microscopy indicated bundle rupture and ion track formation on nanotube bundles. Aligned CNT presented a kind of defect comprising ravine formation and tube agglomeration on top of the substrate. The latter structure is possibly caused by static charge accumulation induced by the incoming ions. Fluence plays a role on the short range order. Higher fluence irradiation transforms CNT into amorphous carbon nanowires.

  10. Agglomeration defects on irradiated carbon nanotubes

    Directory of Open Access Journals (Sweden)

    Cássio Stein Moura

    2012-03-01

    Full Text Available Aligned carbon nanotubes (CNT were irradiated in the longitudinal and perpendicular directions, with low energy carbon and helium ions in order to observe the formation of defects in the atomic structure. Analysis through Raman spectroscopy and scanning electron microscopy indicated bundle rupture and ion track formation on nanotube bundles. Aligned CNT presented a kind of defect comprising ravine formation and tube agglomeration on top of the substrate. The latter structure is possibly caused by static charge accumulation induced by the incoming ions. Fluence plays a role on the short range order. Higher fluence irradiation transforms CNT into amorphous carbon nanowires.

  11. Immobilization of enzymes onto carbon nanotubes

    Directory of Open Access Journals (Sweden)

    Prlainović Nevena Ž.

    2011-01-01

    Full Text Available The discovery of carbon nanotubes (CNTs has opened a new door in nanotechnology. With their high surface area, unique electronic, thermal and mechanical properties, CNTs have been widely used as carriers for protein immobilization. In fact, carbon nanotubes present ideal support system without diffusional limitations, and also have the possibility of surface covalent functionalization. It is usually the oxidation process that introduces carboxylic acid groups. Enzymes and other proteins could be adsorbed or covalently attached onto carbon nanotubes. Adsorption of enzyme is a very simple and inexpensive immobilization method and there are no chemical changes of the protein. It has also been found that this technique does not alter structure and unique properties of nanotubes. However, a major problem in process designing is relatively low stability of immobilized protein and desorption from the carrier. On the other hand, while covalent immobilization provides durable attachment the oxidation process can reduce mechanical and electronic properties of carbon nanotubes. It can also affect the active site of enzyme and cause the loss of enzyme activity. Bioimmobilization studies have showed that there are strong interactions between carbon nanotubes surface and protein. The retention of enzyme structure and activity is critical for their application and it is of fundamental interest to understand the nature of these interactions. Atomic force microscopy (AFM, transmission electron microscopy (TEM, scanning electron microscopy (SEM and circular dichroism (CD spectroscopy provide an insight into the structural changes that occur during the immobilization. The aim of this paper is to summarize progress of protein immobilization onto carbon nanotubes.

  12. Carbon nanotube fiber terahertz polarizer

    Science.gov (United States)

    Zubair, Ahmed; Tsentalovich, Dmitri E.; Young, Colin C.; Heimbeck, Martin S.; Everitt, Henry O.; Pasquali, Matteo; Kono, Junichiro

    2016-04-01

    Conventional, commercially available terahertz (THz) polarizers are made of uniformly and precisely spaced metallic wires. They are fragile and expensive, with performance characteristics highly reliant on wire diameters and spacings. Here, we report a simple and highly error-tolerant method for fabricating a freestanding THz polarizer with nearly ideal performance, reliant on the intrinsically one-dimensional character of conduction electrons in well-aligned carbon nanotubes (CNTs). The polarizer was constructed on a mechanical frame over which we manually wound acid-doped CNT fibers with ultrahigh electrical conductivity. We demonstrated that the polarizer has an extinction ratio of ˜-30 dB with a low insertion loss (fiber polarizer and found comparable attenuation to a commercial metallic wire-grid polarizer. Furthermore, based on the classical theory of light transmission through an array of metallic wires, we demonstrated the most striking difference between the CNT-fiber and metallic wire-grid polarizers: the latter fails to work in the zero-spacing limit, where it acts as a simple mirror, while the former continues to work as an excellent polarizer even in that limit due to the one-dimensional conductivity of individual CNTs.

  13. 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.

  14. Carbon nanotube fiber terahertz polarizer

    Energy Technology Data Exchange (ETDEWEB)

    Zubair, Ahmed [Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005 (United States); Tsentalovich, Dmitri E.; Young, Colin C. [Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005 (United States); Heimbeck, Martin S. [Charles M. Bowden Laboratory, Aviation & Missile Research, Development, and Engineering Center (AMRDEC), Redstone Arsenal, Alabama 35898 (United States); Everitt, Henry O. [Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005 (United States); Charles M. Bowden Laboratory, Aviation & Missile Research, Development, and Engineering Center (AMRDEC), Redstone Arsenal, Alabama 35898 (United States); Pasquali, Matteo [Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005 (United States); Department of Chemistry, Rice University, Houston, Texas 77005 (United States); Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005 (United States); Kono, Junichiro, E-mail: kono@rice.edu [Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005 (United States); Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005 (United States); Department of Physics and Astronomy, Rice University, Houston, Texas 77005 (United States)

    2016-04-04

    Conventional, commercially available terahertz (THz) polarizers are made of uniformly and precisely spaced metallic wires. They are fragile and expensive, with performance characteristics highly reliant on wire diameters and spacings. Here, we report a simple and highly error-tolerant method for fabricating a freestanding THz polarizer with nearly ideal performance, reliant on the intrinsically one-dimensional character of conduction electrons in well-aligned carbon nanotubes (CNTs). The polarizer was constructed on a mechanical frame over which we manually wound acid-doped CNT fibers with ultrahigh electrical conductivity. We demonstrated that the polarizer has an extinction ratio of ∼−30 dB with a low insertion loss (<0.5 dB) throughout a frequency range of 0.2–1.1 THz. In addition, we used a THz ellipsometer to measure the Müller matrix of the CNT-fiber polarizer and found comparable attenuation to a commercial metallic wire-grid polarizer. Furthermore, based on the classical theory of light transmission through an array of metallic wires, we demonstrated the most striking difference between the CNT-fiber and metallic wire-grid polarizers: the latter fails to work in the zero-spacing limit, where it acts as a simple mirror, while the former continues to work as an excellent polarizer even in that limit due to the one-dimensional conductivity of individual CNTs.

  15. Superconductivity in the Carbon Nanotubes

    Science.gov (United States)

    Ieong, Chao

    This is an experimental study of the superconductivity of the carbon nanotubes (CNTs)--more specifically the CNTs studied is 0.4 nm diameter single-wall CNTs existing inside the channels of the AFI zeolite crystal, abbreviated as CNT AFI--by probing the magnetization property of this CNT AFI system. These human engineered 4-Angstrom CNTs, which is a nanoscale and low-dimensional material, are approaching the limit set by nature, and superconductivity in the CNTs in general is theoretically (microscopic or first-principles) both interesting and challenging. Hence, empirical studies are important in providing useful guiding information. The magnetization and specific-heat studies could provide convincing evidences supporting or critiquing the electrical transport results of the CNT AFI system. But probing the superconductivity in this system, as the superconducting signal is very small in a large background, is another challenge. Therefore the high-resolution calorimetry and magnetometry techniques detailedin this thesis are invaluable. With improved method of fabrication to increase the CNTs content inside the channels of the AFI crystallites, the empirical results [Nanoscale 4, 21-41 (2012)]were markedly different from those published in 2001 [Science 292, 2462 (2001)]. The magnetization results of this thesis largely agree with the results from the electrical transport study [Phys. Rev. B 81, 174530 (2010)], but there is some result that raises doubt in the critical current interpretation there. Lastly, there is still some electrical transport result of this system that has not been explained convincingly and is of interest.

  16. Determinants of carbon nanotube toxicity.

    Science.gov (United States)

    Lanone, Sophie; Andujar, Pascal; Kermanizadeh, Ali; Boczkowski, Jorge

    2013-12-01

    In the last few years questions have been raised regarding the potential toxicity of carbon nanotubes (CNTs) to humans and environment. It is believed that the physico-chemical characteristics of these materials are key determinants of CNT interaction with living organisms, and hence determine their toxicity. As for other nanomaterials, the most important of these characteristics are the length, diameter, surface area, tendency to agglomerate, bio-durability, presence and nature of catalyst residues as well as chemical functionalization of the CNT. This review highlights the recent advancements in the understanding of the CNT properties which are essential in determining CNT toxicity. Hence the focus is on CNT dimensions, surface properties, bio-durability and corona formation as these fields have evolved greatly in recent years. A deeper understanding of these events and their underlying mechanisms could provide a molecular explanation of the biological and physiological responses following CNT administration and therefore help in the development of safe by design materials. © 2013 Elsevier B.V. All rights reserved.

  17. Carbon Nanotube Bonding Strength Enhancement Using Metal "Wicking" Process

    Science.gov (United States)

    Lamb, James L.; Dickie, Matthew R.; Kowalczyk, Robert S.; Liao, Anna; Bronikowski, Michael J.

    2012-01-01

    Carbon nanotubes grown from a surface typically have poor bonding strength at the interface. A process has been developed for adding a metal coat to the surface of carbon nano tubes (CNTs) through a wicking process, which could lead to an enhanced bonding strength at the interface. This process involves merging CNTs with indium as a bump-bonding enhancement. Classical capillary theory would not normally allow materials that do not wet carbon or graphite to be drawn into the spacings by capillary action because the contact angle is greater than 90 degrees. However, capillary action can be induced through JPL's ability to fabricate oriented CNT bundles to desired spacings, and through the use of deposition techniques and temperature to control the size and mobility of the liquid metal streams and associated reservoirs. A reflow and plasma cleaning process has also been developed and demonstrated to remove indium oxide, and to obtain smooth coatings on the CNT bundles.

  18. 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.

  19. 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.

  20. 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.

  1. Quenching of Single-Walled Carbon Nanotube Fluorescence by Dissolved Oxygen Reveals Selective Single-Stranded DNA Affinities.

    Science.gov (United States)

    Zheng, Yu; Bachilo, Sergei M; Weisman, R Bruce

    2017-05-04

    The selective interactions between short oligomers of single-stranded DNA (ssDNA) and specific structures of single-walled carbon nanotubes have been exploited in powerful methods for nanotube sorting. We report here that nanotubes coated with ssDNA also display selective interactions through the selective quenching of nanotube fluorescence by dissolved oxygen. In aqueous solutions equilibrated under 1 atm of O 2 , emission intensity from semiconducting nanotubes is reduced by between 9 and 40%, varying with the combination of ssDNA sequence and nanotube structure. This quenching reverses promptly and completely on the removal of dissolved O 2 and may be due to physisorption on nanotube surfaces. Fluorescence quenching offers a simple, nondestructive approach for studying the structure-selective interactions of ssDNA with single-walled carbon nanotubes and identifying recognition sequences.

  2. Quasi-One-Dimensional Electron Gas Bound to a Helium-Coated Nanotube

    Science.gov (United States)

    Liebrecht, Michael; Del Maestro, Adrian; Cole, Milton W.

    2016-05-01

    A much-studied system is the quasi-2D electron gas in image-potential bound states at the surface of helium and hydrogen. In this paper, we report on an analogous quasi-1D system: electrons bound by image-like polarization forces to the surface of a helium-coated carbon nanotube. The potential is computed from an electron-helium pseudopotential, plus a dynamic image term evaluated from a semi-classical model of the nanotube's response function. Predictions are made for the bound states and potential many-body properties of this novel electron gas for a specific choice of tube radius and film thickness.

  3. Synthesis of silver impregnated carbon nanotubes and cyclodextrin ...

    African Journals Online (AJOL)

    Silver impregnated carbon nanotubes and cyclodextrin polymers were synthesised by first functionalising carbon nanotubes in a mixture of nitric and sulphuric acid before impregnating them with silver nanoparticles. The silver impregnated functionalised carbon nanotubes were then polymerised with β cyclodextrin using ...

  4. Carbon nanotubes: Synthesis, characterization, and applications

    Science.gov (United States)

    Deck, Christian Peter

    Carbon nanotubes (CNTs) possess exceptional material properties, making them desirable for use in a variety of applications. In this work, CNTs were grown using two distinct catalytic chemical vapor deposition (CVD) procedures, floating catalyst CVD and thermal CVD, which differed in the method of catalyst introduction. Reaction conditions were optimized to synthesize nanotubes with desired characteristics, and the effects of varying growth parameters were studied. These parameters included gas composition, temperature, reaction duration, and catalyst and substrate material. The CNT products were then examined using several approaches. For each CVD method, nanotube growth rates were determined and the formation and termination mechanisms were investigated. The effects of reaction parameters on nanotube diameters and morphology were also explored to identify means of controlling these important properties. In addition to investigating the effects of different growth parameters, the material properties of nanotubes were also studied. The floating catalyst CVD method produced thick mats of nanotubes, and the mechanical response of these samples was examined using in-situ compression and tension testing. These results indicated that mat structure is composed of discontinuous nanotubes, and a time-dependent response was also observed. In addition, the electrical resistance of bulk CNT samples was found to increase for tubes grown with higher catalyst concentrations and with bamboo morphologies. The properties of nanotubes synthesized using thermal CVD were also examined. Mechanical testing was performed using the same in-situ compression approach developed for floating catalyst CVD samples. A second characterization method was devised, where an optical approach was used to measure the deflection of patterned nanotubes exposed to an applied fluid flow. This response was also simulated, and comparisons with the experimental data were used to determine the flexural

  5. Polymer-Assisted Direct Deposition of Uniform Carbon Nanotube Bundle Networks for High Performance Transparent Electrodes

    KAUST Repository

    Hellstrom, Sondra L.

    2009-06-23

    Flexible transparent electrodes are crucial for touch screen, flat panel display, and solar cell technologies. While carbon nanotube network electrodes show promise, characteristically poor dispersion properties have limited their practicality. We report that addition of small amounts of conjugated polymer to nanotube dispersions enables straightforward fabrication of uniform network electrodes by spin-coating and simultaneous tuning of parameters such as bundle size and density. After treatment in thionyl chloride, electrodes have sheet resistances competitive with other reported carbon nanotube based transparent electrodes to date. © 2009 American Chemical Society.

  6. 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.

  7. Synthesis of Carbon Nanotubes Array by CVD

    Science.gov (United States)

    Zhu, S.; Su, C.; Cochrane, J. C.; Lehoczky, S. L.; Muntele, I.; Ila, D.; Rose, M. Franklin (Technical Monitor)

    2001-01-01

    Since the properties of multi-wall carbon nanotubes (MWCNT) are superior in many devices such as electronics and sensors, many efforts have been involved in synthesizing particular structural or dimensional MWCNT. Uniform aligned MWCNT array is one of the prototype structures for devices such as filed emission device and microelectromechanical systems in which a large length to diameter ratio may also be required. Most aligned MWCNT recently synthesized by plasma enhanced chemical vapor deposition (CVD) have cone shaped structures. This presentation will illustrate aligned MWCNT array synthesized on silicon substrates using thermal CVD that could produce MWCNT with uniform diameter. An array of nickel particles was used as catalyst for MWCNT growth. A thin Ti or Au buffer layer was coated on the substrate prior to depositing nickel particles. Because the MWCNT size depends on the catalyst particle size, the nickel particle size annealed at various temperatures was investigated. MWCNT were grown on the substrate in the temperature range of 700 C - 1000 C and the pressure range of 1 to 300 torr. Methane and hydrogen gases with methane content of 1 - 10 % were used for the MWCNT synthesis. Morphology, length and diameter of MWCNT were determined by scanning electron microscopy and Raman spectroscopy. The detailed results of synthesis and characterizations will be discussed in the presentation.

  8. Bio-inspired Hybrid Carbon Nanotube Muscles

    Science.gov (United States)

    Kim, Tae Hyeob; Kwon, Cheong Hoon; Lee, Changsun; An, Jieun; Phuong, Tam Thi Thanh; Park, Sun Hwa; Lima, Márcio D.; Baughman, Ray H.; Kang, Tong Mook; Kim, Seon Jeong

    2016-05-01

    There has been continuous progress in the development for biomedical engineering systems of hybrid muscle generated by combining skeletal muscle and artificial structure. The main factor affecting the actuation performance of hybrid muscle relies on the compatibility between living cells and their muscle scaffolds during cell culture. Here, we developed a hybrid muscle powered by C2C12 skeletal muscle cells based on the functionalized multi-walled carbon nanotubes (MWCNT) sheets coated with poly(3,4-ethylenedioxythiophene) (PEDOT) to achieve biomimetic actuation. This hydrophilic hybrid muscle is physically durable in solution and responds to electric field stimulation with flexible movement. Furthermore, the biomimetic actuation when controlled by electric field stimulation results in movement similar to that of the hornworm by patterned cell culture method. The contraction and relaxation behavior of the PEDOT/MWCNT-based hybrid muscle is similar to that of the single myotube movement, but has faster relaxation kinetics because of the shape-maintenance properties of the freestanding PEDOT/MWCNT sheets in solution. Our development provides the potential possibility for substantial innovation in the next generation of cell-based biohybrid microsystems.

  9. Electrospun Carbon Nanotube-Reinforced Nanofiber.

    Science.gov (United States)

    Kim, Sung Mm; Hee Kim, Sung; Choi, Myong Soo; Lee, Jun Young

    2016-03-01

    We fabricated multi-walled carbon nanotube (MWNT) reinforced polyurethane (PU) nanofiber (MWNT-PU) web via electrospinning. In order to optimize the electrospinning conditions, we investigated the effects of various parameters including kind of solvent, viscosity of the spinning solution, and flow rate on the spinnability and properties of nanofiber. N,N-dimethylformamide (DMF), tetrahydrofuran (THF) and their mixture with various volume ratio were used as the spinning solvent. Morphology of the nanofiber was studied using scanning electron microscope (SEM) and transmission electron microscope (TEM), confirming successful fabrication of MWNT-PU nanofiber web with uniform dispersion of MWNT in longitudinal direction of the fiber. The MWNT-PU nanofiber web exhibited two times higher tensile strength than PU nanofiber web. We also fabricated electrically conducting MWNT-PU nanofiber web by coating poly(3,4-ehtylenedioxythiophene) (PEDOT) on the surface of MWNT-PU nanofiber web for electromagnetic interference (EMI) shielding application. The electromagnetic interference shielding effectiveness (EMI SE) was quite high as 25 dB in the frequency range from 50 MHz to 10 GHz.

  10. Detection of gas atoms with carbon nanotubes

    Science.gov (United States)

    Arash, B.; Wang, Q.

    2013-01-01

    Owning to their unparalleled sensitivity resolution, nanomechanical resonators have excellent capabilities in design of nano-sensors for gas detection. The current challenge is to develop new designs of the resonators for differentiating distinct gas atoms with a recognizably high sensitivity. In this work, the characteristics of impulse wave propagation in carbon nanotube-based sensors are investigated using molecular dynamics simulations to provide a new method for detection of noble gases. A sensitivity index based on wave velocity shifts in a single-walled carbon nanotube, induced by surrounding gas atoms, is defined to explore the efficiency of the nano-sensor. The simulation results indicate that the nano-sensor is able to differentiate distinct noble gases at the same environmental temperature and pressure. The inertia and the strengthening effects by the gases on wave characteristics of carbon nanotubes are particularly discussed, and a continuum mechanics shell model is developed to interpret the effects.

  11. 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.

  12. Modelling Carbon Nanotubes-Based Mediatorless Biosensor

    Directory of Open Access Journals (Sweden)

    Julija Razumiene

    2012-07-01

    Full Text Available This paper presents a mathematical model of carbon nanotubes-based mediatorless biosensor. The developed model is based on nonlinear non-stationary reaction-diffusion equations. The model involves four layers (compartments: a layer of enzyme solution entrapped on a terylene membrane, a layer of the single walled carbon nanotubes deposited on a perforated membrane, and an outer diffusion layer. The biosensor response and sensitivity are investigated by changing the model parameters with a special emphasis on the mediatorless transfer of the electrons in the layer of the enzyme-loaded carbon nanotubes. The numerical simulation at transient and steady state conditions was carried out using the finite difference technique. The mathematical model and the numerical solution were validated by experimental data. The obtained agreement between the simulation results and the experimental data was admissible at different concentrations of the substrate.

  13. Orientational Growth of Carbon Nanotube for Applications

    Science.gov (United States)

    Zhu, Shen; Su, Ching-Hua; Cochrane, J. C.; Lehoczky, S.; Cui, Y.; Burger, A.; Whitaker, Ann F. (Technical Monitor)

    2001-01-01

    Since the superior properties of multi-wall carbon nanotubes (MWCNT) could improve numerous devices such as electronics and sensors, many efforts have been made in investigating the growth mechanism of MWCNT to synthesize high quality MWCNT. Most applications require uniform aligned CNT. In this presentation, a directional growth of CNT will be reported. Carbon nanotubes are synthesized using thermal chemical vapor deposition. Temperature and pressure are two important growth parameters for fabricating carbon nanotubes. It is found that the nanotube diameter distribution mainly depends on the growth-temperature. With the substrate surface normal either along or against the gravity vector, different growth orientations of MWCNT are observed by scanning electron microscopy although the Raman spectra are similar for samples synthesized at different locations. The sizes of these carbon nanotubes in each sample are quite uniform and the length of the tube is up to several tens of micrometers. These results suggest the gravitation effects in the growth of long and small diameter CNT.

  14. Lipid nanoscaffolds in carbon nanotube arrays

    Science.gov (United States)

    Paukner, Catharina; Koziol, Krzysztof K. K.; Kulkarni, Chandrashekhar V.

    2013-09-01

    We present the fabrication of lipid nanoscaffolds inside carbon nanotube arrays by employing the nanostructural self-assembly of lipid molecules. The nanoscaffolds are finely tunable into model biomembrane-like architectures (planar), soft nanochannels (cylindrical) or 3-dimensionally ordered continuous bilayer structures (cubic). Carbon nanotube arrays hosting the above nanoscaffolds are formed by packing of highly oriented multiwalled carbon nanotubes which facilitate the alignment of lipid nanostructures without requiring an external force. Furthermore, the lipid nanoscaffolds can be created under both dry and hydrated conditions. We show their direct application in reconstitution of egg proteins. Such nanoscaffolds find enormous potential in bio- and nano-technological fields.We present the fabrication of lipid nanoscaffolds inside carbon nanotube arrays by employing the nanostructural self-assembly of lipid molecules. The nanoscaffolds are finely tunable into model biomembrane-like architectures (planar), soft nanochannels (cylindrical) or 3-dimensionally ordered continuous bilayer structures (cubic). Carbon nanotube arrays hosting the above nanoscaffolds are formed by packing of highly oriented multiwalled carbon nanotubes which facilitate the alignment of lipid nanostructures without requiring an external force. Furthermore, the lipid nanoscaffolds can be created under both dry and hydrated conditions. We show their direct application in reconstitution of egg proteins. Such nanoscaffolds find enormous potential in bio- and nano-technological fields. Electronic supplementary information (ESI) available: Additional wide angle X-ray scattering (WAXS) data on the alignment of lipid nanostructures, control and time resolved 2-d images of egg ovalbumin encapsulation and a summary picture of the present work. See DOI: 10.1039/c3nr02068a

  15. Phase Behavior of Carbon Nanotube Suspensions

    Science.gov (United States)

    Poulin, Philippe

    2006-03-01

    We study the phase behavior of nanotube suspensions stabilized by surfactants or amphiphilic polymers. The control of the composition of the solutions allows the interaction potential between the nanotubes to be finely tuned. As a consequence, it is possible to quantitatively analyze important phenomena such as percolation or liquid crystalline phase transitions. In particular, we describe how the percolation of rod-like particles is quantitatively decreased in the presence of attractive interactions (1). We show that rod-like particles respond much more strongly than spheres to attractive interactions; strengthening thereby the technological interest of carbon nanotubes to achieve low percolation thresholds for electrostatic dissipation or electromagnetic shielding. By contrast, carbon nanotubes which experience repulsive interactions can spontaneously order and form liquid crystalline solutions (2). Aligning and packing nanotubes is a major challenge to obtain macroscopic materials with improved properties. We will briefly discuss at the end of the presentation, our latest results concerning the fabrication of fibers aligned nanotubes (3). In particular, we will present new treatments of these fibers which lead to unusual mechanical properties and shape memory effects with giant stress recovery (4). *B. Vigolo, C. Coulon, M. Maugey, C. Zakri, P. Poulin, Science 2005. *S. Badaire, C. Zakri, M. Maugey, A. Derr'e, J. Barisci, G. Wallace, P. Poulin, Adv. Mat. 2005. *P. Miaudet, M. Maugey, A. Derr'e, V. Pichot, P. Launois, P. Poulin, C. Zakri, Nanoletters 2005. *P. Miaudet, A. Derr'e, M. Maugey, C. Zakri, P. Poulin, in preparation.

  16. 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.

  17. Effective Trapping of Lithium Polysulfides Using a Functionalized Carbon Nanotube-Coated Separator for Lithium-Sulfur Cells with Enhanced Cycling Stability.

    Science.gov (United States)

    Ponraj, Rubha; Kannan, Aravindaraj G; Ahn, Jun Hwan; Lee, Jae Hee; Kang, Joonhee; Han, Byungchan; Kim, Dong-Won

    2017-11-08

    The critical issues that hinder the practical applications of lithium-sulfur batteries, such as dissolution and migration of lithium polysulfides, poor electronic conductivity of sulfur and its discharge products, and low loading of sulfur, have been addressed by designing a functional separator modified using hydroxyl-functionalized carbon nanotubes (CNTOH). Density functional theory calculations and experimental results demonstrate that the hydroxyl groups in the CNTOH provoked strong interaction with lithium polysulfides and resulted in effective trapping of lithium polysulfides within the sulfur cathode side. The reduction in migration of lithium polysulfides to the lithium anode resulted in enhanced stability of the lithium electrode. The conductive nature of CNTOH also aided to efficiently reutilize the adsorbed reaction intermediates for subsequent cycling. As a result, the lithium-sulfur cell assembled with a functional separator exhibited a high initial discharge capacity of 1056 mAh g-1 (corresponding to an areal capacity of 3.2 mAh cm-2) with a capacity fading rate of 0.11% per cycle over 400 cycles at 0.5 C rate.

  18. Synthesis and application of novel ion-imprinted polymer coated magnetic multi-walled carbon nanotubes for selective solid phase extraction of lead(II) ions.

    Science.gov (United States)

    Fayazi, Maryam; Taher, Mohammad Ali; Afzali, Daryoush; Mostafavi, Ali; Ghanei-Motlagh, Masoud

    2016-03-01

    In this study, novel magnetic ion-imprinted polymer (MIIP) nanoparticles were utilized for the sensitive and selective detection of Pb(II) ions by graphite furnace atomic absorption spectrometry (GFAAS). The Pb(II)-imprinted polymer was synthesized by using 4-vinylpyridine (4VP) as the functional monomer, ethylene glycol dimethacrylate (EGDMA) as the cross-linker, 2,3,5,6-tetra(2-pyridyl) pyrazine (TPPZ) as the chelating agent and magnetic multi-walled carbon nanotubes (MMWCNTs) as the carrier. The synthesized MIIP materials were characterized by field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and vibrating sample magnetometer (VSM). Various analytical parameters such as extraction and desorption time, eluent type and concentration, pH and sample volume were systematically examined. The selectivity of MIIP sorbent for Pb(II) ions in the presence of some cations was also evaluated. The limit of detection (LOD, 3S(b)) and the relative standard deviation (RSD, n=8, c=25 ng L(-1)) were found to be 2.4 ng L(-1) and 5.6%, respectively. The maximum sorption capacity of the MIIP for Pb(II) was found to be 48.1 mg g(-1). Finally, the proposed analytical procedure was successfully applied to monitoring lead in human hair and water samples with satisfactory results for the spiked samples. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. 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.

  20. Carbon nanotubes as anti-bacterial agents.

    Science.gov (United States)

    Mocan, Teodora; Matea, Cristian T; Pop, Teodora; Mosteanu, Ofelia; Buzoianu, Anca Dana; Suciu, Soimita; Puia, Cosmin; Zdrehus, Claudiu; Iancu, Cornel; Mocan, Lucian

    2017-10-01

    Multidrug-resistant bacterial infections that have evolved via natural selection have increased alarmingly at a global level. Thus, there is a strong need for the development of novel antibiotics for the treatment of these infections. Functionalized carbon nanotubes through their unique properties hold great promise in the fight against multidrug-resistant bacterial infections. This new family of nanovectors for therapeutic delivery proved to be innovative and efficient for the transport and cellular translocation of therapeutic molecules. The current review examines the latest progress in the antibacterial activity of carbon nanotubes and their composites.

  1. Carbon nanotubes as nanopipette: modelling and simulations

    Science.gov (United States)

    Hwang, Ho Jung; Byun, Ki Ryang; Kang, Jeong Won

    2004-06-01

    This paper shows that carbon nanotubes can be applied to a nanopipette. Nanospace in atomic force microscope multi-wall carbon nanotube tips is filled with molecules and atoms with charges and then, the tips can be applied to nanopipette when the encapsulated media flow off under applying electrostatic forces. Since the nanospace inside the tips can be refilled, the tips can be permanently used in ideal conditions of no chemical reaction and no mechanical deformation. Molecular dynamics simulations for nanopipette applications showed the possibility of nanolithography or single-metallofullerene-transistor array fabrication.

  2. Topological phase diagram of superconducting carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Milz, Lars; Marganska-Lyzniak, Magdalena; Grifoni, Milena [Institut I - Theoretische Physik Universitaet Regensburg (Germany)

    2016-07-01

    The topological superconducting phase diagram of superconducting carbon nanotubes is discussed. Under the assumption of a short-ranged pairing potential, there are two spin-singlet states: an s-wave and an exotic p + ip-wave that are possible because of the special structure of the honeycomb lattice. The consequences for the possible presence of Majorana edge states in carbon nanotubes are addressed. In particular, regions in the magnetic field-chemical potential plane possibly hosting localized Majorana modes are discussed.

  3. Carbon Nanotube-Enhanced Carbon-Phenenolic Ablator Material

    Science.gov (United States)

    Kikolaev, P.; Stackpoole, M.; Fan, W.; Cruden, B. A.; Waid, M.; Moloney, P.; Arepalli, S.; Arnold, J.; Partridge, H.; Yowell, L.

    2006-01-01

    This viewgraph presentation reviews the use of PICA (phenolic impregnated carbon ablator) as the selected material for heat shielding for future earth return vehicles. It briefly reviews the manufacturing of PICA and the advantages for the use of heat shielding, and then explains the reason for using Carbon Nanotubes to improve strength of phenolic resin that binds carbon fibers together. It reviews the work being done to create a carbon nanotube enhanced PICA. Also shown are various micrographic images of the various PICA materials.

  4. 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.

  5. Coating Carbon Fibers With Platinum

    Science.gov (United States)

    Effinger, Michael R.; Duncan, Peter; Coupland, Duncan; Rigali, Mark J.

    2007-01-01

    A process for coating carbon fibers with platinum has been developed. The process may also be adaptable to coating carbon fibers with other noble and refractory metals, including rhenium and iridium. The coated carbon fibers would be used as ingredients of matrix/fiber composite materials that would resist oxidation at high temperatures. The metal coats would contribute to oxidation resistance by keeping atmospheric oxygen away from fibers when cracks form in the matrices. Other processes that have been used to coat carbon fibers with metals have significant disadvantages: Metal-vapor deposition processes yield coats that are nonuniform along both the lengths and the circumferences of the fibers. The electrical resistivities of carbon fibers are too high to be compatible with electrolytic processes. Metal/organic vapor deposition entails the use of expensive starting materials, it may be necessary to use a furnace, and the starting materials and/or materials generated in the process may be hazardous. The present process does not have these disadvantages. It yields uniform, nonporous coats and is relatively inexpensive. The process can be summarized as one of pretreatment followed by electroless deposition. The process consists of the following steps: The surfaces of the fiber are activated by deposition of palladium crystallites from a solution. The surface-activated fibers are immersed in a solution that contains platinum. A reducing agent is used to supply electrons to effect a chemical reduction in situ. The chemical reduction displaces the platinum from the solution. The displaced platinum becomes deposited on the fibers. Each platinum atom that has been deposited acts as a catalytic site for the deposition of another platinum atom. Hence, the deposition process can also be characterized as autocatalytic. The thickness of the deposited metal can be tailored via the duration of immersion and the chemical activity of the solution.

  6. 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.

  7. Geckolike high shear strength by carbon nanotube fiber adhesives

    Science.gov (United States)

    Maeno, Y.; Nakayama, Y.

    2009-01-01

    Carbon nanotube adhesives can adhere strongly to surfaces as a gecko does. The number of carbon nanotube layers is an important determinant of the contact area for adhesion. Balancing the catalyst ratio and buffer layer used for chemical vapor deposition processing controls the number of carbon nanotube layers and their distribution. The features of carbon nanotubes determine the shear strength of adhesion. Carbon nanotubes with a broad distribution of layers exhibit enhanced shear strength with equivalent adhesive capability to that of a natural Tokay Gecko (Gekko gecko)

  8. CVD fabrication of carbon nanotubes on electrodeposited flower-like Fe nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Zanganeh, Saeid, E-mail: SAZ@engr.uconn.ed [Department of Electrical and Computer Engineering, University of Connecticut, 371 Fairfield Way, U-2157 Storrs, CT 06269-2157 (United States); Department of Materials Science and Engineering, Center of Excellence for Production of Advanced Materials, Sharif University of Technology, P.O. Box 11365-9466, Tehran (Iran, Islamic Republic of); Torabi, Morteza [Department of Metallurgy and Materials Engineering, Iran University of Science and Technology, P.O. Box 16845-161, Tehran (Iran, Islamic Republic of); Department of Materials Science and Engineering, Center of Excellence for Production of Advanced Materials, Sharif University of Technology, P.O. Box 11365-9466, Tehran (Iran, Islamic Republic of); Kajbafvala, Amir [Department of Materials Science and Engineering, North Carolina State University, 911 Partner' s Way, Raleigh, NC 27695-7907 (United States); Zanganeh, Navid [Chemical Engineering Department, Amirkabir University of Technology, P.O. Box 15875-4413, Tehran (Iran, Islamic Republic of); Bayati, M.R.; Molaei, Roya; Zargar, H.R. [Department of Metallurgy and Materials Engineering, Iran University of Science and Technology, P.O. Box 16845-161, Tehran (Iran, Islamic Republic of); Sadrnezhaad, S.K. [Department of Materials Science and Engineering, Center of Excellence for Production of Advanced Materials, Sharif University of Technology, P.O. Box 11365-9466, Tehran (Iran, Islamic Republic of)

    2010-10-08

    Research highlights: {yields} The latest results obtained about production of flower-like nanostructured Fe catalysts deposited electrochemically on platinum electrodes (as a suitable catalyst for synthesis of carbon nanotubes) are presented in this paper. {yields} CVD is used as a convenient way of deposition of CNTs on the flower-like Fe catalyst substrate. - Abstract: Galvanostatic method was used to electrodeposit Fe nanostructures on platinum electrodes as catalysts. Scanning electron microscopy (SEM) revealed flower-like Fe deposits with high surface area. Carbon nanotubes were grown on flower-like Fe nanostructures by chemical vapor deposition. The structure of the synthesized carbon nanotubes was investigated by scanning electron microscopy, transmission electron microscopy, Raman spectroscopy and X-ray diffraction. According to X-ray diffraction patterns, Fe was the only detected constituent of the deposited coating. The carbon nanotubes had small wall-thickness and wide hollow core.

  9. Growth of carbon nanotubes from C{sub 60}

    Energy Technology Data Exchange (ETDEWEB)

    Morjan, R.E.; Nerushev, O.A.; Sveningsson, M.; Rohmund, F.; Falk, L.K.L.; Campbell, E.E.B. [Department of Experimental Physics, Goeteborg University and Chalmers University of Technology, 41296, Goeteborg (Sweden)

    2004-02-01

    Carbon nanotubes can be obtained from a multitude of molecular precursors in chemical vapor deposition (CVD) processes. Here we demonstrate that the use of C{sub 60} as the carbon feedstock gas in an iron-catalyzed thermal CVD experiment leads to the formation of films of multi-walled carbon nanotubes. The critical role of the diameter of the catalyst particles in determining the efficiency of nanotube growth is clearly demonstrated. Electron microscopy and Raman spectroscopy were employed for the characterisation of the nanotube material. The structural properties of the individual nanotubes show distinctive differences to acetylene-grown multi-walled nanotubes. (orig.)

  10. 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.

  11. Selective ion transport in functionalized carbon nanotubes

    Science.gov (United States)

    Samoylova, Olga N.; Calixte, Emvia I.; Shuford, Kevin L.

    2017-11-01

    Ion transport through functionalized carbon nanotubes in an external electric field is studied using all atom molecular dynamics simulations. The surface of carbon nanotubes has been functionalized with hydrogens and hydroxyl groups, and ionic current passing through the nanochannels has been examined with respect to the extent of surface modification. We are able to dramatically increase the ionic current passing through the nanotube via the appropriate surface modification. An analysis of the electrostatic potential within the tube shows higher ionic currents result from an increase in accessible pathways coupled with a global shift toward more direct ion passage. Moreover, through judicious choice of structure, the current can be modulated to a large degree with ion selectivity.

  12. Coupling of carbon and peptide nanotubes.

    Science.gov (United States)

    Montenegro, Javier; Vázquez-Vázquez, Carlos; Kalinin, Arseny; Geckeler, Kurt E; Granja, Juan R

    2014-02-12

    Two of the main types of nanotubular architectures are the single-walled carbon nanotubes (SWCNTs) and the self-assembling cyclic peptide nanotubes (SCPNs). We here report the preparation of the dual composite resulting from the ordered combination of both tubular motifs. In the resulting architecture, the SWCNTs can act as templates for the assembly of SCPNs that engage the carbon nanotubes noncovalently via pyrene "paddles", each member of the resulting hybrid stabilizing the other in aqueous solution. The particular hybrids obtained in the present study formed highly ordered oriented arrays and display complementary properties such as electrical conductivity. Furthermore, a self-sorting of the cyclic peptides toward semiconducting rather than metallic SWCNTs is also observed in the aqueous dispersions. It is envisaged that a broad range of exploitable properties may be achieved and/or controlled by varying the cyclic peptide components of similar SWCNT/SCPN hybrids.

  13. A solid-phase microextraction platinized stainless steel fiber coated with a multiwalled carbon nanotube-polyaniline nanocomposite film for the extraction of thymol and carvacrol in medicinal plants and honey.

    Science.gov (United States)

    Ghiasvand, Alireza; Dowlatshah, Samira; Nouraei, Nadia; Heidari, Nahid; Yazdankhah, Fatemeh

    2015-08-07

    A mechanically hard and cohesive porous fiber, with large surface area, for more strong attachment of the coating was provided by platinizing a stainless steel wire. Then, the platinized stainless steel fiber was coated with a multiwalled carbon nanotube/polyaniline (MWCNT/PANI) nanocomposite using electrophoretic deposition (EPD) method and applied for the extraction of thymol and carvacrol with direct-immersion solid-phase microextraction (DI-SPME) method followed by high-performance liquid chromatography-ultraviolet detection (HPLC-UV) quantification. To provide a larger coarse surface for the tightened attachment of coating on the fiber, a stainless steel wire was platinized using a suitable optimized EPD method. Different experimental parameters were studied and the optimal conditions were obtained as: pH of the sample solution: 2; extraction time: 60min; salt content in the sample solution: 1% w/v NaNO3; desorption time: 60min; type and volume of the desorption solvent: acetonitrile, 100μL. Under the optimized conditions, limits of detection (LODs) were 0.6 and 0.8μgmL(-1) for thymol and carvacrol, respectively. Linear dynamic range (LDR) for the calibration curves of both analytes were 1-80μgmL(-1). Relative standard deviation (RSD%, n=6) was 6.8 for thymol and 12.7 for carvacrol. The proposed fiber was successfully applied for the recovery and determination of thymol and carvacrol in thyme, savory, and honey samples. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Investigation of Chirality Selection Mechanism of Single Walled Carbon Nanotube

    Science.gov (United States)

    2016-12-13

    ALD) followed by coating with a 1-nm-thick Fe thin film by e-beam evaporation. The substrates were cut into small pieces in the dimensions of about...60 keV at Korea Multi-Purpose Accelerator Complex. The dose of Fe+ ion was 1016/cm2. As a control sample, 1 nm- thin Fe film was deposited on a...research involved investigation of two fundamental mechanisms of carbon nanotube (CNT) growth: chirality selection of single-walled CNT (SWCNT) and

  15. Preparation and characterization of amphiphilic multi-walled carbon nanotubes

    Science.gov (United States)

    Qiu, Jun; Wang, Guojian; Zhao, Caixia

    2008-04-01

    Multiwalled carbon nanotubes (MWCNTs, average diameter 8 nm) functionalized by N-vinyl pyrrolidone (NVP) were synthesized by radical polymerization and characterized by Fourier transform infrared and Raman spectroscopies, thermogravimetric analysis and transmission electron microscopy. These NVP-MWCNTs exhibit remarkable solubility in water, ethanol and dimethyl formamide. The polyvinyl pyrrolidone can be attached onto the surface of the MWCNTs and the degree of functionalization is affected by NVP content. The functionalization causes possible grafting reaction and solid physical coating between MWCNTs and PVP.

  16. Flow-driven voltage generation in carbon nanotubes

    Indian Academy of Sciences (India)

    The flow of various liquids and gases over single-walled carbon nanotube bundles induces an electrical signal (voltage/current) in the sample along the ... to the nanotubes, the gas flow effect can be seen for a variety of solids ranging from single and multi-walled carbon nanotubes, graphite and doped semiconductors.

  17. 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...

  18. Reactive Molecular Simulation of the Damage Mitigation Efficacy of POSS-, Graphene-, and Carbon Nanotube-Loaded Polyimide Coatings Exposed to Atomic Oxygen Bombardment.

    Science.gov (United States)

    Rahmani, Farzin; Nouranian, Sasan; Li, Xiaobing; Al-Ostaz, Ahmed

    2017-04-12

    Reactive molecular dynamics simulation was employed to compare the damage mitigation efficacy of pristine and polyimide (PI)-grafted polyoctahedral silsesquioxane (POSS), graphene (Gr), and carbon nanotubes (CNTs) in a PI matrix exposed to atomic oxygen (AO) bombardment. The concentration of POSS and the orientation of Gr and CNT nanoparticles were further investigated. Overall, the mass loss, erosion yield, surface damage, AO penetration depth, and temperature evolution are lower for the PI systems with randomly oriented CNTs and Gr or PI-grafted POSS compared to those of the pristine POSS or aligned CNT and Gr systems at the same nanoparticle concentration. On the basis of experimental early degradation data (before the onset of nanoparticle damage), the amount of exposed PI, which has the highest erosion yield of all material components, on the material surface is the most important parameter affecting the erosion yield of the hybrid material. Our data indicate that the PI systems with randomly oriented Gr and CNT nanoparticles have the lowest amount of exposed PI on the material surface; therefore, a lower erosion yield is obtained for these systems compared to that of the PI systems with aligned Gr and CNT nanoparticles. However, the PI/grafted-POSS system has a significantly lower erosion yield than that of the PI systems with aligned Gr and CNT nanoparticles, again due to a lower amount of exposed PI on the surface. When comparing the PI systems loaded with PI-grafted POSS versus pristine POSS at low and high nanoparticle concentrations, our data indicate that grafting the POSS and increasing the POSS concentration lower the erosion yield by a factor of about 4 and 1.5, respectively. The former is attributed to a better dispersion of PI-grafted POSS versus that of the pristine POSS in the PI matrix, as determined by the radial distribution function.

  19. Single-walled carbon nanotubes coated fibers for solid-phase microextraction and gas chromatography-mass spectrometric determination of pesticides in Tea samples.

    Science.gov (United States)

    Wu, Fang; Lu, Wanping; Chen, Jinghua; Liu, Wei; Zhang, Lan

    2010-08-15

    Using a single-walled carbon nanotubes (SWCNTs) as stationary phase of solid-phase microextraction (SPME) fibers, a simple, low cost and environmentally friendly method for extraction of 13 pesticides in Tea samples has been developed following gas chromatography-mass spectrometric determination. Potential factors affecting the extraction efficiency were investigated and optimized, including extraction and desorption time, extraction temperature, stirring rate, solution pH and ionic strength. Under optimized conditions, the linearity of the developed method was in the range of 0.125-25 ng/mL with correlation coefficients greater than 0.9928 and the limits of detections (LODs) were 0.027-0.23 ng/mL (S/N=3). Meanwhile, the relative standard deviations (RSDs) for five successive measurements with single fiber, fiber-to-fiber, day-to-day were 2.3-13.0, 8.2-14.6 and 4.1-12.5%, respectively, indicating good reproducibility of the proposed method. The fiber had high extraction efficiency for studied pesticides in comparison with commercial poly(dimethylsiloxane) (PDMS) and polyacrylate (PA) fibers and could be used for more than 70 times without decrease of efficiency. The developed method was successfully applied for the analysis of real samples including green Tea, oolong Tea, white Tea, and flower Tea, and the recoveries of the pesticides spiked in these samples ranged from 75.1 to 118.4%. Chlorfenapyr and lambda-cyhalothrin were found in the Tea samples bought randomly from local market. The results demonstrated that the developed SWCNTs-SPME method was a simple, efficient pretreatment and enrichment procedure for pesticides in complex matrices. Copyright 2010 Elsevier B.V. All rights reserved.

  20. 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.

  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. 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

  3. 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...

  4. 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...

  5. 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…

  6. Biodistribution of Carbon Nanotubes in Animal Models

    DEFF Research Database (Denmark)

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

    2017-01-01

    The many interesting 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...

  7. 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...

  8. 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.

  9. 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

  10. In-line manufacture of carbon nanotubes

    Science.gov (United States)

    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.

  11. Conductivity of single-walled carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Gets, A. V.; Krainov, V. P., E-mail: vpkrainov@mail.ru [Moscow Institute of Physics and Technology (Russian Federation)

    2016-12-15

    The conductivity of single-walled carbon nanotubes at low temperatures is calculated. It is shown that it is much higher than the well-known conductivity of a model 1D Fermi system. This is a purely quantum-mechanical effect.

  12. Chemical vapor deposition of carbon nanotube forests

    Energy Technology Data Exchange (ETDEWEB)

    Robertson, J.; Zhong, G.; Esconjauregui, S.; Zhang, C.; Fouquet, M.; Hofmann, S. [Engineering Department, Cambridge University, Cambridge CB2 1PZ (United Kingdom)

    2012-12-15

    We review the growth mechanisms of vertically aligned carbon nanotube forests, in terms of what controls the growth rate and control of the catalyst lifetime. We also review the production of very high-density forests, in terms of increasing the catalyst particle density. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  13. Electrochemical Metal Deposition on Carbon Nanotubes

    Czech Academy of Sciences Publication Activity Database

    Dunsch, L.; Janda, Pavel; Mukhopadhyay, K.; Shinohara, H.

    2001-01-01

    Roč. 11, č. 6 (2001), s. 427-435 ISSN 1344-9931 Institutional research plan: CEZ:AV0Z4040901 Keywords : carbon nanotubes * electrodeposition * cyclic voltammetry Subject RIV: CG - Electrochemistry Impact factor: 0.800, year: 2001

  14. 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.

  15. Defect complexes in carbon and boron nitride nanotubes

    CSIR Research Space (South Africa)

    Mashapa, MG

    2012-05-01

    Full Text Available The effect of defect complexes on the stability, structural and electronic properties of single-walled carbon nanotubes and boron nitride nanotubes is investigated using the ab initio pseudopotential density functional method implemented...

  16. Transparent and Electrically Conductive Carbon Nanotube-Polymer Nanocomposite Materials for Electrostatic Charge Dissipation

    Science.gov (United States)

    Dervishi, E.; Biris, A. S.; Biris, A. R.; Lupu, D.; Trigwell, S.; Miller, D. W.; Schmitt, T.; Buzatu, D. A.; Wilkes, J. G.

    2006-01-01

    In recent years, nanocomposite materials have been extensively studied because of their superior electrical, magnetic, and optical properties and large number of possible applications that range from nano-electronics, specialty coatings, electromagnetic shielding, and drug delivery. The aim of the present work is to study the electrical and optical properties of carbon nanotube(CNT)-polymer nanocomposite materials for electrostatic charge dissipation. Single and multi-wall carbon nanotubes were grown by catalytic chemical vapor deposition (CCVD) on metal/metal oxide catalytic systems using acetylene or other hydrocarbon feedstocks. After the purification process, in which amorphous carbon and non-carbon impurities were removed, the nanotubes were functionalized with carboxylic acid groups in order to achieve a good dispersion in water and various other solvents. The carbon nanostructures were analyzed, both before and after functionalization by several analytical techniques, including microscopy, Raman spectroscopy, and X-Ray photoelectron spectroscopy. Solvent dispersed nanotubes were mixed (1 to 7 wt %) into acrylic polymers by sonication and allowed to dry into 25 micron thick films. The electrical and optical properties of the films were analyzed as a function of the nanotubes' concentration. A reduction in electrical resistivity, up to six orders of magnitude, was measured as the nanotubes' concentration in the polymeric films increased, while optical transparency remained 85 % or higher relative to acrylic films without nanotubes.

  17. 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.

  18. Carbon-Nanotube-Based Electrodes for Biomedical Applications

    Science.gov (United States)

    Li, Jun; Meyyappan, M.

    2008-01-01

    A nanotube array based on vertically aligned nanotubes or carbon nanofibers has been invented for use in localized electrical stimulation and recording of electrical responses in selected regions of an animal body, especially including the brain. There are numerous established, emerging, and potential applications for localized electrical stimulation and/or recording, including treatment of Parkinson s disease, Tourette s syndrome, and chronic pain, and research on electrochemical effects involved in neurotransmission. Carbon-nanotube-based electrodes offer potential advantages over metal macroelectrodes (having diameters of the order of a millimeter) and microelectrodes (having various diameters ranging down to tens of microns) heretofore used in such applications. These advantages include the following: a) Stimuli and responses could be localized at finer scales of spatial and temporal resolution, which is at subcellular level, with fewer disturbances to, and less interference from, adjacent regions. b) There would be less risk of hemorrhage on implantation because nano-electrode-based probe tips could be configured to be less traumatic. c) Being more biocompatible than are metal electrodes, carbon-nanotube-based electrodes and arrays would be more suitable for long-term or permanent implantation. d) Unlike macro- and microelectrodes, a nano-electrode could penetrate a cell membrane with minimal disruption. Thus, for example, a nanoelectrode could be used to generate an action potential inside a neuron or in proximity of an active neuron zone. Such stimulation may be much more effective than is extra- or intracellular stimulation via a macro- or microelectrode. e) The large surface area of an array at a micron-scale footprint of non-insulated nanoelectrodes coated with a suitable electrochemically active material containing redox ingredients would make it possible to obtain a pseudocapacitance large enough to dissipate a relatively large amount of electric charge

  19. Nicotine adsorption on single wall carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Girao, Eduardo C. [Departamento de Fisica, Universidade Federal do Ceara, Caixa Postal 6030, Campus do Pici, 60455-900 Fortaleza, Ceara (Brazil); Fagan, Solange B.; Zanella, Ivana [Area de Ciencias Tecnologicas, Centro Universitario Franciscano - UNIFRA, 97010-032 Santa Maria, RS (Brazil); Filho, Antonio G. Souza, E-mail: agsf@fisica.ufc.br [Departamento de Fisica, Universidade Federal do Ceara, Caixa Postal 6030, Campus do Pici, 60455-900 Fortaleza, Ceara (Brazil)

    2010-12-15

    This work reports a theoretical study of nicotine molecules interacting with single wall carbon nanotubes (SWCNTs) through ab initio calculations within the framework of density functional theory (DFT). Different adsorption sites for nicotine on the surface of pristine and defective (8,0) SWCNTs were analyzed and the total energy curves, as a function of molecular position relative to the SWCNT surface, were evaluated. The nicotine adsorption process is found to be energetically favorable and the molecule-nanotube interaction is intermediated by the tri-coordinated nitrogen atom from the nicotine. It is also predicted the possibility of a chemical bonding between nicotine and SWCNT through the di-coordinated nitrogen.

  20. 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.

  1. Preparation of carbon nanotube bioconjugates for biomedical applications

    OpenAIRE

    Liu, Zhuang; Tabakman, Scott M; Chen, Zhuo; Dai, Hongjie

    2009-01-01

    Biomedical applications of carbon nanotubes have attracted much attention in recent years. Here, we summarize our previously developed protocols for functionalization and bioconjugation of single-walled carbon nanotubes (SWNTs) for various biomedical applications including biological imaging; using nanotubes as Raman, photoluminescence and photoacoustic labels; sensing using nanotubes as Raman tags and drug delivery. Sonication of SWNTs in solutions of phospholipid-polyethylene glycol (PL-PEG...

  2. International Assessment of Carbon Nanotube Manufacturing and Applications

    Science.gov (United States)

    2007-06-01

    in Japan. Similarly, nanotubes (SWCNTs and MWCNTs) have been added to ceramic materials (e.g., alumina ) to enhance the fracture toughness of the...ICMR was built around Eklund’s work to mass- produce nanopowders produced by CO2 laser pyrolysis. ICMR moved to Silicon Valley two years later and...nanotube secondary battery using carbon nanotubes (Korea) • Method of synthesizing carbon nanotubes in the multistage bipolar alumina mould and

  3. 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.

  4. Double quantum dots in carbon nanotubes

    Science.gov (United States)

    von Stecher, Javier; Wunsch, Bernhard; Lukin, Mikhail; Demler, Eugene; Rey, Ana Maria

    2010-03-01

    We study the behavior of few-electrons confined in a double-well quantum dot in semiconducting carbon nanotubes. These carbon nanostructures exhibit richer physics than GaAs ones due to the additional valley degree of freedom. We calculate and characterize the low energy eigenstates in the presence of a magnetic field and double-well detuning. Spin-orbit coupling lifts the spin and valley degeneracy and, in the presence of exchange interactions, leads, at small detunings and weak magnetic fields, to a spin-valley antisymmetric two-electron ground state which is not a pure spin-singlet state. At large detuning, the strong Coulomb interactions accessible in carbon nanotubes can substantially modify the non-interacting eigenstates via higher orbital-level mixing. The latter manifest in current transport experiments by the disappearance of the Pauli blockade.

  5. Optical trapping of carbon nanotubes and graphene

    Directory of Open Access Journals (Sweden)

    S. Vasi

    2011-09-01

    Full Text Available We study optical trapping of nanotubes and graphene. We extract the distribution of both centre-of-mass and angular fluctuations from three-dimensional tracking of these optically trapped carbon nanostructures. The optical force and torque constants are measured from auto and cross-correlation of the tracking signals. We demonstrate that nanotubes enable nanometer spatial, and femto-Newton force resolution in photonic force microscopy by accurately measuring the radiation pressure in a double frequency optical tweezers. Finally, we integrate optical trapping with Raman and photoluminescence spectroscopy demonstrating the use of a Raman and photoluminescence tweezers by investigating the spectroscopy of nanotubes and graphene flakes in solution. Experimental results are compared with calculations based on electromagnetic scattering theory.

  6. Carbon Nanotubes: Measuring Dispersion and Length

    Energy Technology Data Exchange (ETDEWEB)

    Fagan, Jeffrey A.; Bauer, Barry J.; Hobbie, Erik K.; Becker, Matthew L.; Hight-Walker, Angela; Simpson, Jeffrey R.; Chun, Jaehun; Obrzut, Jan; Bajpai, Vardhan; Phelan, Fred R.; Simien, Daneesh; Yeon Huh, Ji; Migler, Kalman B.

    2011-03-01

    Advanced technological uses of single-wall carbon nanotubes (SWCNTs) rely on the production of single length and chirality populations that are currently only available through liquid phase post processing. The foundation of all of these processing steps is the attainment of individualized nanotube dispersion in solution; an understanding of the collodial properties of the dispersed SWCNTs can then be used to designed appropriate conditions for separations. In many instances nanotube size, particularly length, is especially active in determining the achievable properties from a given population, and thus there is a critical need for measurement technologies for both length distribution and effective separation techniques. In this Progress Report, we document the current state of the art for measuring dispersion and length populations, including separations, and use examples to demonstrate the desirability of addressing these parameters.

  7. Contact resistance of carbon nanotubes and metals

    Science.gov (United States)

    Choi, Hyoung Joon; Ihm, Jisoon; Yoon, Young-Gui; Louie, Steven G.

    2000-03-01

    The quantum conductance of a metallic carbon nanotube with one end immersed in a jellium metal is studied. We find that the incident π-band electrons go through the tube without being scattered by the surrounding metal and contribute a quantum unit (2e^2/h) to the conductance. On the other hand, the incident π-band electrons experience strong resonant back-scattering because the low-angular-momentum states at the Fermi level have a dominantly metallic character in the nanotube-jellium metal coexistence region. These results provide a possible explanation for the experimentally observed conductance of one quantum unit instead of two for nanotubes with one end dipped into liquid metal such as mercury. The detailed form of the immersion-length dependence of the conductance, which is strongly related to the coherence of the electronic state in the immersed part of the tube, will also be discussed.

  8. 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.

  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. Aligned carbon nanotube, graphene and graphite oxide thin films via substrate-directed rapid interfacial deposition.

    Science.gov (United States)

    D'Arcy, Julio M; Tran, Henry D; Stieg, Adam Z; Gimzewski, James K; Kaner, Richard B

    2012-05-21

    A procedure for depositing thin films of carbon nanostructures is described that overcomes the limitations typically associated with solution based methods. Transparent and conductively continuous carbon coatings can be grown on virtually any type of substrate within seconds. Interfacial surface tension gradients result in directional fluid flow and film spreading at the water/oil interface. Transparent films of carbon nanostructures are produced including aligned ropes of single-walled carbon nanotubes and assemblies of single sheets of chemically converted graphene and graphite oxide. Process scale-up, layer-by-layer deposition, and a simple method for coating non-activated hydrophobic surfaces are demonstrated.

  11. 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.

  12. C{sub 60} fullerene decoration of carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Demin, V. A., E-mail: victordemin88@gmail.com [Russian Academy of Sciences, Emanuel Institute of Biochemical Physics (Russian Federation); Blank, V. D.; Karaeva, A. R.; Kulnitskiy, B. A.; Mordkovich, V. Z. [Technological Institute for Superhard and Novel Carbon Materials (Russian Federation); Parkhomenko, Yu. N. [National University of Science and Technology MISiS (Russian Federation); Perezhogin, I. A.; Popov, M. Yu. [Technological Institute for Superhard and Novel Carbon Materials (Russian Federation); Skryleva, E. A. [National University of Science and Technology MISiS (Russian Federation); Urvanov, S. A. [Technological Institute for Superhard and Novel Carbon Materials (Russian Federation); Chernozatonskii, L. A. [Russian Academy of Sciences, Emanuel Institute of Biochemical Physics (Russian Federation)

    2016-12-15

    A new fully carbon nanocomposite material is synthesized by the immersion of carbon nanotubes in a fullerene solution in carbon disulfide. The presence of a dense layer of fullerene molecules on the outer nanotube surface is demonstrated by TEM and XPS. Fullerenes are redistributed on the nanotube surface during a long-term action of an electron beam, which points to the existence of a molecular bond between a nanotube and fullerenes. Theoretical calculations show that the formation of a fullerene shell begins with the attachment of one C{sub 60} molecule to a defect on the nanotube surface.

  13. Carbon nanotubes: Sensor properties. A review

    Directory of Open Access Journals (Sweden)

    Irina V. Zaporotskova

    2016-12-01

    Full Text Available Recent publications dealing with dealing with the fabrication of gas and electrochemical biosensors based on carbon nanotubes have been reviewed. Experimental and theoretical data on the working principles of nanotubes have been presented. The main regularities of the structure, energy parameters and sensor properties of modified semiconducting systems on the basis of cabon nanotubes have been studied by analyzing the mechanisms of nanotubule interaction with functional groups (including carboxyl and amino groups, metallic nanoparticles and polymers leading to the formation of chemically active sensors. The possibility of using boundary modified nanotubes for the identification of metals has been discussed. Simulation results have been reported for the interaction of nanotubes boundary modified by –СООН and –NH2 groups with atoms and ions of potassium, sodium and lithium. The simulation has been carried out using the molecular cluster model and the MNDO and DFT calculation methods. Sensors fabricated using this technology will find wide application for the detection of metallic atoms and their ions included in salts and alkali.

  14. Synthesis of Carbon Nanotubes Using Sol Gel Route

    Science.gov (United States)

    Abdel-Fattah, Tarek

    2002-12-01

    Since 1990, carbon nanotubes were discovered and they have been the object of intense scientific study ever since. A carbon nanotube is a honeycomb lattice rolled into a cylinder. The diameter of a carbon nanotube is of nanometer size and the length is in the range of micrometer. Many of the extraordinary properties attributed to nanotubes, such as tensile strength and thermal stability, have inspired predictions of microscopic robots, dent-resistant car bodies and earthquake-resistant buildings. The first products to use nanotubes were electrical. Some General Motors cars already include plastic parts to which nanotubes were added; such plastic can be electrified during painting so that the paint will stick more readily. Two nanotube-based lighting and display products are well on their way to market. In the long term, perhaps the most valuable applications will take further advantage of nanotubes' unique electronic properties. Carbon nanotubes can in principle play the same role as silicon does in electronic circuits, but at a molecular scale where silicon and other standard semiconductors cease to work. There are several routes to synthesize carbon nanotubes; laser vaporization, carbon arc and vapor growth. We have applied a different route using sol gel chemistry to obtain carbon nanotubes. This work is patent-pending.

  15. Modifying the response of a polymer-based quartz crystal microbalance hydrocarbon sensor with functionalized carbon nanotubes.

    Science.gov (United States)

    Pejcic, Bobby; Myers, Matthew; Ranwala, Nilukshi; Boyd, Leigh; Baker, Murray; Ross, Andrew

    2011-09-15

    This report compares the performance of polymer and carbon nanotube-polymer composite membranes on a quartz crystal microbalance (QCM) sensor for the detection of aromatic hydrocarbons (benzene, toluene, ethylbenzene, p-xylene and naphthalene) in aqueous solutions. Several different polymers (polystyrene, polystyrene-co-butadiene, polyisobutylene and polybutadiene) and types of functionalized carbon nanotubes (multi-walled and single-walled carbon nanotubes) were investigated at varying carbon nanotube (CNT) loading levels and film thicknesses. In a majority of instances, the difference in response between membranes comprising pure polymer and membranes containing 10% (w/w) carbon nanotubes were not statistically significant. However, a notable exception is the decreasing sensitivity towards p-xylene with increasing carbon nanotube content in a polybutadiene film. This variation in sensitivity can be attributed to a change in the sorption mechanism from absorption into the polymer phase to adsorption onto the carbon nanotube sidewalls. With much thicker coatings of 10% (w/w) carbon nanotube in polybutadiene, the sensitivity towards toluene was higher compared to the pure polymer. The increased toluene sensitivity may be partially attributed to an increase in the sorption capacity of a carbon nanotube polymer composite film relative to its corresponding pure polymer film. Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) measurements were performed to understand the mechanism of sorption and these studies showed that the addition of functionalized CNT to the polymer increases the absorption of certain types of hydrocarbons. This study demonstrates that carbon nanotubes can be incorporated into a polymer-coated QCM sensor and that composite films may be used to modify the QCM response and selectivity during the analysis of complex hydrocarbon mixtures. Crown Copyright © 2011. Published by Elsevier B.V. All rights reserved.

  16. Fabrication and application of polymer composites comprising carbon nanotubes.

    Science.gov (United States)

    Mylvaganam, Kausala; Zhang, Liangchi C

    2007-01-01

    Carbon nanotubes are being used in place of carbon fibers in making composites due to their high strength, high aspect-ratio and excellent thermal and electrical conductivity. Although carbon nanotubes were discovered more than a decade ago, works on preparation of satisfactory composites reinforced by carbon nanotubes have encountered difficulties. This review will discuss some registered patents and relevant papers on the fabrication of carbon nanotube-polymer composites on improving material properties such as electrical conductivity, mechanical strength, and radiation detection which have a broad range of applications in nano-electronic devices, and space and medical elements.

  17. 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.

  18. Reduction of harmful nitrogen oxide emission from low heat rejection diesel engine using carbon nanotubes

    Directory of Open Access Journals (Sweden)

    Thulasi Gopinathan

    2016-01-01

    Full Text Available In this study, lanthanum aluminate is used as thermal barrier coating material for the first time in the internal combustion engine to convert the standard engine into low heat rejection engine. Initially, the biodiesel is prepared from sunflower oil by using trans-esterification process. The piton crown, cylinder head and valves of the engine is coated with lanthanum aluminate for a thickness of around 200 microns. However, the analysis of performance and emission characteristics of a standard diesel is carried out with diesel/biodiesel to compare with the low heat rejection engine. The lanthanum aluminate coated engine fueled with sunflower methyl ester shows better performance and emission. But the emission of NOx founds to be higher in the coated engine. Further, a small quantity of carbon nanotubes is added onto the biodiesel to carry out the experiments. Based on the results, the carbon nanotubes are added with the biodiesel to reduce the emission of NOx.

  19. Highly efficient iodide/triiodide dye-sensitized solar cells with gel-coated reduce graphene oxide/single-walled carbon nanotube composites as the counter electrode exhibiting an open-circuit voltage of 0.90 V.

    Science.gov (United States)

    Zheng, Huiqin; Neo, Chin Yong; Ouyang, Jianyong

    2013-07-24

    To increase the open-circuit voltage (Voc) of dye-sensitized solar cells (DSCs), it is crucial to enhance the photovoltaic efficiency of DSCs. Here, we report an effective method to significantly improve the Voc and photovoltaic efficiency of DSCs by using gel-coated composites of reduced graphene oxide (rGO) and single-walled carbon nanotubes (SWCNTs) as the counter electrode. Gel-coated rGO-SWCNT composites outperform Pt, rGO and SWCNTs in catalyzing the reduction of I3(-) and functioning as the counter electrode of DSCs. The Voc and power conversion efficiency (PCE) are 0.86 V and 8.37% for fresh DSCs with the composite of 80 wt % rGO and 20 wt % SWCNTs, significantly higher than those (Voc = 0.77 V, PCE = 7.79%) of control DSCs with Pt fabricated by pyrolysis as the counter electrode. The Voc value of DSCs with rGO-SWCNT composites as the counter electrode further increases to 0.90 V after one week. The high Voc and PCE are ascribed to the synergetic effects of rGO and SWCNTs in reducing the overpotential of the I3(-) reduction. RGO with high specific surface area can have high electrocatalytic activity, whereas SWCNTs give rise to high conductivity for the composites and facilitate the penetration of the redox species into rGO sheets by preventing the agglomeration of the rGO sheets. To the best of our knowledge, this is the first time to report iodide/triiodide DSCs with both high Voc and PCE.

  20. 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.

  1. Processing and Properties of Carbon Nanotube PVC Composites

    Directory of Open Access Journals (Sweden)

    Kristin Trommer

    2014-01-01

    Full Text Available Commercially available multiwalled carbon nanotubes (MWCNT were incorporated in coating masses based on PVC by means of three roll mill. The best results could be obtained using the 5 µm gap. Thin PVC sheets were formed via knife coating having an electrical conductivity up to 1,500 S/m that are applicable as electric heating elements. For the use in the antistatic range, CNT contents ≤0.5% are sufficient. Rheological measurements indicate the quality of particle processing. AFM investigations are suitable to investigate the alignment of the nanoparticles in the bulk polymer. Using this method, the decrease of agglomerates as well as the splitting of CNT bundles within further mass processing could be visualized.

  2. Effect of the rheological properties of carbon nanotube dispersions on the processing and properties of transparent conductive electrodes.

    Science.gov (United States)

    Maillaud, Laurent; Poulin, Philippe; Pasquali, Matteo; Zakri, Cécile

    2015-06-02

    Transparent conductive films are made from aqueous surfactant stabilized dispersions of carbon nanotubes using an up-scalable rod coating method. The processability of the films is governed by the amount of surfactant which is shown to alter strongly the wetting and viscosity of the ink. The increase of viscosity results from surfactant mediated attractive interactions between the carbon nanotubes. Links between the formulation, ink rheological properties, and electro-optical properties of the films are determined. The provided guidelines are generalized and used to fabricate optimized electrodes using conductive polymers and carbon nanotubes. In these electrodes, the carbon nanotubes act as highly efficient viscosifiers that allow the optimized ink to be homogeneously spread using the rod coating method. From a general point of view and in contrast to previous studies, the CNTs are optimally used in the present approach as conductive additives for viscosity enhancements of electronic inks.

  3. Preparation of Si-carbon nanotube composite by decomposition of tetramethylsilane (TMS and its hydrogen storage property

    Directory of Open Access Journals (Sweden)

    Tatsumi Ishihara, Masashi Nakasu, Isamu Yasuda and Hiroshige Matsumoto

    2006-01-01

    Full Text Available Hydrogen storage property of Si-carbon nanotube composite was studied. It was found that the carbon nanotube coated Si particle was prepared by the decomposition of tetramethylsilane by using Ni catalyst. The obtained composite was consisted of the spherical Si particle with 300 nm diameter and the surface of Si particle was coated with carbon nanotube with 10 nm diameter. The obtained Si-carbon nanotube composite shows a fairly large hydrogen storage capacity of 2.5 wt%. The amount of storage H2 increased with increasing the preparation temperature and the largest hydrogen storage amount could be achieved at 1273 K for 6 h. Fairly large hydrogen storage capacity could be sustained after 3 cycles of adsorption and desorption.

  4. 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...... already been demonstrated in more classical formats, for improved separation performance in gas and liquid chromatography, and for unique applications in solid phase extraction. Carbon nanotubes are now also entering the field of microfluidics, where there is a large potential to be able to provide...... integrated, tailor-made nanotube columns by means of catalytic growth of the nanotubes inside the fluidic channels. An evaluation of the different implementations of carbon nanotubes and related carbon-based nanomaterials for microfluidic chromatography devices is given in terms of separation performance...

  5. The Vibration of a Linear Carbon Chain in Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Dongqing Ding

    2017-04-01

    Full Text Available An explicit solution for the vibration of a carbon chain inside carbon nanotubes (CNTs was obtained using continuum modeling of the van der Waals (vdW interactions between them. The effect of the initial tensile force and the amplitude of the carbon chain as well as the radii of the CNTs on the vibration frequency were analyzed in detail, respectively. Our analytical results show that the vibration frequency of the carbon chain in a (5,5 CNT could be around two orders of magnitude higher than that of an independent carbon chain without initial tensile force. For a given CNT radius, the vibration frequency nonlinearly increases with increasing amplitude and initial tensile force. The obtained analytical cohesive energy and vibration frequency are reasonable by comparison of present molecular dynamics (MD simulations. These findings will be a great help towards understanding the vibration property of a nanowire in nanotubes, and designing nanoelectromechanical devices.

  6. Synthesis and characterization of carbon-coated cobalt ferrite nanoparticles

    Science.gov (United States)

    Bakhshi, Hamed; Shokuhfar, Ali; Vahdati, Nima

    2016-09-01

    Cobalt ferrite nanoparticles (CFNPs) were prepared via a reverse micelle method. The CFNPs were subsequently coated with carbon shells by means of thermal chemical vapor deposition (TCVD). In this process, acetylene gas (C2H2) was used as a carbon source and the coating was carried out for 1, 2, or 3 h at 750°C. The Ar/C2H2 ratio was 10:1. Heating during the TCVD process resulted in a NP core size that approached 30 nm; the thickness of the shell was less than 10 nm. The composition, structure, and morphology of the fabricated composites were characterized using X-ray diffraction, simultaneous thermal analysis, transmission electron microscopy, high-resolution transmission electron microscopy, and selected-area diffraction. A vibrating sample magnetometer was used to survey the samples' magnetic properties. The deposited carbon shell substantially affected the growth and magnetic properties of the CFNPs. Micro-Raman spectroscopy was used to study the carbon coating and revealed that the deposited carbon comprised graphite, multiwalled carbon nanotubes, and diamond- like carbon. With an increase in coating time, the intensity ratio between the amorphous and ordered peaks in the Raman spectra decreased, which indicated an increase in crystallite size.

  7. Multifunctional Flexible Composites Based on Continuous Carbon Nanotube Fiber

    Science.gov (United States)

    2014-07-28

    emitters, solid-phase microextraction and catalysis . Different from graphene- based aerogels (GBAs) and membranes (GBMs), GBFs have demonstrated...nanotube dry-spun yarns, Carbon, 48, 2802–2811, 2010. 22. A. S. Wu and T. -W. Chou. Carbon nanotube fibers for advanced composites, Materials Today , 15...Applied Physics Letters, 100, 201908, 2012. 8. A. S. Wu and T. -W. Chou. Carbon nanotube fibers for advanced composites, Materials Today , 15, 302

  8. 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.

  9. Quantum dot attachment and morphology control by carbon nanotubes

    OpenAIRE

    Juarez, Beatriz H.; Klinke, Christian; Kornowski, Andreas; Weller, Horst

    2008-01-01

    Novel applications in nanotechnology rely on the design of tailored nano-architectures. For this purpose, carbon nanotubes and nanoparticles are intensively investigated. In this work we study the influence of non-functionalized carbon nanotubes on the synthesis of CdSe nanoparticles by means of organometallic colloidal routes. This new synthesis methodology does not only provide an effective path to attach nanoparticles non-covalently to carbon nanotubes but represents also a new way to cont...

  10. Quantum Dot Attachment and Morphology Control by Carbon Nanotubes

    Science.gov (United States)

    Juárez, Beatriz H.; Klinke, Christian; Kornowski, Andreas; Weller, Horst

    2007-12-01

    Novel applications in nanotechnology rely on the design of tailored nano-architectures. For this purpose, carbon nanotubes and nanoparticles are intensively investigated. In this work we study the influence of non-functionalized carbon nanotubes on the synthesis of CdSe nanoparticles by means of organometallic colloidal routes. This new synthesis methodology does not only provide an effective path to attach nanoparticles non-covalently to carbon nanotubes but represents also a new way to control the shape of nanoparticles.

  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. Density controlled carbon nanotube array electrodes

    Science.gov (United States)

    Ren, Zhifeng F [Newton, MA; Tu, Yi [Belmont, MA

    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.

  14. Carbon Nanotube Composites from Modified Plant Oils

    Science.gov (United States)

    McAninch, Ian; Wool, Richard

    2006-03-01

    Carbon nanotubes (CNTs) with their impressive mechanical properties are ideal reinforcement material. Acrylated epoxidized soy oil (AESO) has been previously shown to have favorable interactions with carbon nanotubes. CNTs mixed into AESO, both with and without styrene as a co-monomer, using mechanical shear mixing showed dispersion only on the micron level, resulting in modest mechanical property improvements. Greater improvements were seen, especially in the rubbery modulus, when the resin's viscosity was kept high, either through a reduction of the styrene content, or by curing at a lower temperature. CNTs were also dispersed via sonication in methyl methacrylate. The resulting dispersion was then mixed with AESO. The resulting composites showed better CNT dispersion, with no micron-sized aggregates, as verified using SEM and optical microscopy. The mechanical properties also showed greater improvement.

  15. Direct growth of vertically aligned carbon nanotubes on silicon ...

    African Journals Online (AJOL)

    Vertically aligned carbon nanotubes have been synthesized by spray pyrolysis from Glycine max oil on silicon substrate using ferrocene as catalyst at 650 °C. Glycine max oil, a plant-based hydrocarbon precursor was used as a source of carbon and argon as a carrier gas. The as-grown vertically aligned carbon nanotubes ...

  16. 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…

  17. 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

  18. Metallic/semiconducting ratio of carbon nanotubes in a bundle ...

    Indian Academy of Sciences (India)

    Since from the discovery of single wall carbon nanotubes (SWNTs) by. Iijima and Ichihashi [1], much efforts have been devoted to improve the methods of nanotube production, and significant progress has been made to narrow the diame- ter distribution of nanotubes produced by different catalysts and growth processes.

  19. Adsorption mechanism of different organic chemicals on fluorinated carbon nanotubes.

    Science.gov (United States)

    Li, Hao; Zheng, Nan; Liang, Ni; Zhang, Di; Wu, Min; Pan, Bo

    2016-07-01

    Multi-walled carbon nanotubes (MC) were fluorinated by a solid-phase reaction method using polytetrafluoroethylene (PTFE). The surface alteration of carbon nanotubes after fluorination (MC-F) was confirmed based on surface elemental analysis, TEM and SEM. The incorporation of F on MC surface was discussed as F incorporation on carbon defects, replacement of carboxyl groups, as well as surface coating of PTFE. The adsorption performance and mechanisms of MC-F for five kinds of representative organic compounds: sulfamethoxazole (SMX), ofloxacin (OFL), norfloxacin (NOR), bisphenol a (BPA) and phenanthrene (PHE) were investigated. Although BET-N2 surface area of the investigated CNTs decreased after fluorination, the adsorption of all five chemicals increased. Because of the glassification of MC-F surface coating during BET-N2 surface area measurement, the accessible surface area of MC-F was underestimated. Desorption hysteresis was generally observed in all the sorption systems in this study, and the desorption hysteresis of MC-F were stronger than the pristine CNTs. The enhanced adsorption of MC-F may be attributed the pores generated on the coated PTFE and the dispersed CNT aggregates due to the increased electrostatic repulsion after fluorination. The rearrangement of the bundles or diffusion of the adsorbates in MC-F inner pores were the likely reason for the strong desorption hysteresis of MC-F. The butterfly structure of BPA resulted in its high sorption and strong desorption hysteresis. The exothermic sorption character of OFL on CNTs resulted in its strong desorption hysteresis. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Improved cellular uptake of functionalized single-walled carbon nanotubes

    Science.gov (United States)

    Antonelli, A.; Serafini, S.; Menotta, M.; Sfara, C.; Pierigé, F.; Giorgi, L.; Ambrosi, G.; Rossi, L.; Magnani, M.

    2010-10-01

    Single-walled carbon nanotubes (SWNTs) due to their unique structural and physicochemical properties, have been proposed as delivery systems for a variety of diagnostic and therapeutic agents. However, SWNTs have proven difficult to solubilize in aqueous solution, limiting their use in biological applications. In an attempt to improve SWNTs' solubility, biocompatibility, and to increase cell penetration we have thoroughly investigated the construction of carbon scaffolds coated with aliphatic carbon chains and phospholipids to obtain micelle-like structures. At first, oxidized SWNTs (2370 ± 30 nmol mg - 1 of SWNTs) were covalently coupled with an alcoholic chain (stearyl alcohol, C18H37OH; 816 nmol mg - 1 of SWNTs). Subsequently, SWNTs-COOC18H37 derivatives were coated with phosphatidylethanolamine (PE) or -serine (PS) phospholipids obtaining micelle-like structures. We found that cellular uptake of these constructs by phagocytic cells occurs via an endocytotic mechanism for constructs larger than 400 nm while occurs via diffusion through the cell membrane for constructs up to 400 nm. The material that enters the cell by phagocytosis is actively internalized by macrophages and localizes inside endocytotic vesicles. In contrast the material that enters the cells by diffusion is found in the cell cytosol. In conclusion, we have realized new biomimetic constructs based on alkylated SWNTs coated with phospholipids that are efficiently internalized by different cell types only if their size is lower than 400 nm. These constructs are not toxic to the cells and could now be explored as delivery systems for non-permeant cargoes.

  1. Tip-enhanced nano-Raman analytical imaging of locally induced strain distribution in carbon nanotubes.

    Science.gov (United States)

    Yano, Taka-Aki; Ichimura, Taro; Kuwahara, Shota; H'dhili, Fekhra; Uetsuki, Kazumasa; Okuno, Yoshito; Verma, Prabhat; Kawata, Satoshi

    2013-01-01

    Tip-enhanced Raman scattering microscopy is a powerful technique for analysing nanomaterials at high spatial resolution far beyond the diffraction limit of light. However, imaging of intrinsic properties of materials such as individual molecules or local structures has not yet been achieved even with a tip-enhanced Raman scattering microscope. Here we demonstrate colour-coded tip-enhanced Raman scattering imaging of strain distribution along the length of a carbon nanotube. The strain is induced by dragging the nanotube with an atomic force microscope tip. A silver-coated nanotip is employed to enhance and detect Raman scattering from specific locations of the nanotube directly under the tip apex, representing deformation of its molecular alignment because of the existence of local strain. Our technique remarkably provides an insight into localized variations of structural properties in nanomaterials, which could prove useful for a variety of applications of carbon nanotubes and other nanomaterials as functional devices and materials.

  2. Super-tough carbon-nanotube fibres

    Science.gov (United States)

    Dalton, Alan B.; Collins, Steve; Muñoz, Edgar; Razal, Joselito M.; Ebron, Von Howard; Ferraris, John P.; Coleman, Jonathan N.; Kim, Bog G.; Baughman, Ray H.

    2003-06-01

    The energy needed to rupture a fibre (its toughness) is five times higher for spider silk than for the same mass of steel wire, which has inspired efforts to produce spider silk commercially. Here we spin 100-metre-long carbon-nanotube composite fibres that are tougher than any natural or synthetic organic fibre described so far, and use these to make fibre supercapacitors that are suitable for weaving into textiles.

  3. Carbon Nanotube Membranes for Water Purification

    Science.gov (United States)

    Bakajin, Olgica

    2009-03-01

    Carbon nanotubes are an excellent platform for the fundamental studies of transport through channels commensurate with molecular size. Water transport through carbon nanotubes is also believed to be similar to transport in biological channels such as aquaporins. I will discuss the transport of gas, water and ions through microfabricated membranes with sub-2 nanometer aligned carbon nanotubes as ideal atomically-smooth pores. The measured gas flow through carbon nanotubes exceeded predictions of the Knudsen diffusion model by more than an order of magnitude. The measured water flow exceeded values calculated from continuum hydrodynamics models by more than three orders of magnitude and is comparable to flow rates extrapolated from molecular dynamics simulations and measured for aquaporins. More recent reverse osmosis experiments reveal ion rejection by our membranes. Based on our experimental findings, the current understanding of the fundamentals of water and gas transport and of ion rejection will be discussed. The potential application space that exploits these unique nanofluidic phenomena will be explored. The extremely high permeabilities of these membranes, combined with their small pore size will enable energy efficient filtration and eventually decrease the cost of water purification.[4pt] In collaboration with Francesco Fornasiero, Biosciences and Biotechnology Division, PLS, LLNL, Livermore, CA 94550; Sangil Kim, NSF Center for Biophotonics Science & Technology, University of California at Davis, Sacramento CA 95817; Jung Bin In, Mechanical Engineering Department, UC Berkeley, Berkeley CA 94720; Hyung Gyu Park, Jason K Holt, and Michael Stadermann, Biosciences and Biotechnology Division, PLS, LLNL; Costas P. Grigoropoulos, Mechanical Engineering Department, UC Berkeley; Aleksandr Noy, Biosciences and Biotechnology Division, PLS, LLNL and School of Natural Sciences, University of California at Merced.

  4. 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.

  5. 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.

  6. Fermentation based carbon nanotube bionic functional composites

    OpenAIRE

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

    2016-01-01

    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 mechanical and physical properties that are not produced by abiotic processes. Based on grape must and bread fermentation, a bionic composite made of carbon nanotubes (CNTs) and single-cell fungi, the Saccharomyces cerevisiae yeast extract, was prepared by fermentation of such microorganisms at r...

  7. 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. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Theoretical analysis of hydrogen spillover mechanism on carbon nanotubes

    National Research Council Canada - National Science Library

    Juarez-Mosqueda, Rosalba; Mavrandonakis, Andreas; Kuc, Agnieszka B; Pettersson, Lars G M; Heine, Thomas

    2015-01-01

    The spillover mechanism of molecular hydrogen on carbon nanotubes in the presence of catalytically active platinum clusters was critically and systematically investigated by using density-functional theory...

  9. 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.

  10. Review of toxicity studies of carbon nanotubes.

    Science.gov (United States)

    Kobayashi, Norihiro; Izumi, Hiroto; Morimoto, Yasuo

    2017-09-28

    We reviewed studies on pulmonary, reproductive, and developmental toxicity caused by carbon nanotubes (CNTs). In paricular, we analyzed how CNT exposure affects the several processes of pulmonary toxicity, including inflammation, injury, fibrosis, and pulmonary tumors. In pulmonary toxicity, there are various processes, including inflammation, injury, fibrosis, respiratory tumor in the lungs, and biopersistence of CNTs and genotoxicity as tumor-related factors, to develop the respiratory tumor. We evaluated the evidence for the carcinogenicity of CNTs in each process. In the fields of reproductive and developmental toxicity, studies of CNTs have been conducted mainly with mice. We summarized the findings of reproductive and developmental toxicity studies of CNTs. In animal studies, exposure to CNTs induced sustained inflammation, fibrosis, lung cancer following long-term inhalation, and gene damage in the lung. CNTs also showed high biopersistence in animal studies. Fetal malformations after intravenous and intraperitoneal injections and intratracheal instillation, fetal loss after intravenous injection, behavioral changes in offsprings after intraperitoneal injection, and a delay in the delivery of the first litter after intratracheal instillation were reported in mice-administered multi-walled carbon nanotubes (MWCNTs). Single-walled carbon nanotubes (SWCNTs) appeared to be embryolethal and teratogenic in mice when given by intravenous injection; moreover, the tubes induced death and growth retardation in chicken embryos. CNTs are considered to have carcinogenicity and can cause lung tumors. However, the carcinogenicity of CNTs may attenuate if the fiber length is shorter. The available data provide initial information on the potential reproductive and developmental toxicity of CNTs.

  11. 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.

  12. Preparation of Multiwalled Carbon Nanotube-Poly (4-Styrenesulfonic Acid Aqueous Dispersion for Dopamine Sensing

    Directory of Open Access Journals (Sweden)

    Aihua LIU

    2006-12-01

    Full Text Available A simple and facile method for the non-covalent functionalization of multi-walled carbon nanotubes (MWNTs using poly(4-styrenesulfonic acid (PSS is proposed. The resulting PSS-MWNTs dispersion is readily soluble in water and can be left to stand for 2 weeks at room temperature, no phase separation with aggregation of nanotubes at the bottom of the vials was observed. The as-prepared PSS-MWNTs dispersions could facilitate the processing of the nanotubes into composites with high nanotube loading. The PSS-MWNTs complex shows high electrocatalytic activity to the oxidation of neutrontransmitter of dopamine, suggesting that the coating of PSS onto carbon nanotubes surface without destroying the electronic structures of the pristine carbon nanotubes; therefore, the unique properties including the catalytic property of the nanotubes retained. It is envisioned that the PSS-MWNTs aqueous dispersions may find possible applications in the development of biosensors, bioelectronics, separation and environment protection as well as other biological events where water-based environment is required.

  13. Carbon paste electrode incorporating multi-walled carbon nanotube ...

    Indian Academy of Sciences (India)

    The preparation and electrochemical performance of the carbon nanotube paste electrode modified with ferrocene (FCMCNPE) was investigated for electrocatalytic behaviour toward oxidation of -acetyl--cysteine (NAC) in the presence of tryptophan (Trp) using cyclic voltammetry (CV) and differential pulse voltammetry ...

  14. Growth and characterization of carbon nanotubes and zinc oxide nanocomposite with the PECVD technique

    Science.gov (United States)

    Salar Elahi, A.; Ghoranneviss, M.

    In this research 50-100 nm Carbon Nanotube and Zinc Oxide (CNT-ZnO) Nanocomposite were synthesized. We have initially prepared Multi-walled Carbon Nanotubes (MWCNTs) by the Plasma Enhanced Chemical Vapour Deposition (PECVD) method. By two different methods, then, ZnO layers were coated on the tubes. Radio Frequency (RF) sputtering was one of the ways to directly deposit ZnO thin layer on the MWCNTs. Alternatively, we used thermally Physical Vapour Deposition (PVD) for making thin Zn film to oxidize it later. Results were analyzed and discussed.

  15. 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

  16. 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.

  17. Effect of accelerated thermal ageing on the selective solar thermal harvesting properties of multiwall carbon nanotube/nickel oxide nanocomposite coatings

    CSIR Research Space (South Africa)

    Roro, Kittessa T

    2012-05-01

    Full Text Available intensity in the D and G bands of disordered and graphitic carbon, respectively but an enhancement of the NiO bands indicating loss of carbon atoms due to thermal ageing tests. Simple equations are derived determining the proportion of carbon atoms...

  18. Carbon Nanotube Based Devices for Intracellular Analysis

    Science.gov (United States)

    Singhal, Riju Mohan

    Scientific investigations on individual cells have gained increasing attention in recent years as efforts are being made to understand cellular functioning in complex processes, such as cell division during embryonic development, and owing to realization of heterogeneity amongst a population of a single cell type (for instance, certain individual cancer cells being immune to chemotherapy). Therefore devices enabling electrochemical detection, spectroscopy, optical observations, and separation techniques, along with cell piercing and fluid transfer capabilities at the intra-cellular level, are required. Glass pipettes have conventionally been used for single cell interrogation, however their poor mechanical properties and an intrusive conical geometry have led to limited precision and frequent cell damage or death, justifying research efforts to develop novel, non-intrusive cell probes. Carbon nanotubes (CNTs) are known for their superior physical properties and tunable chemical structure. They possess a high aspect ratio and offer minimally invasive thin carbon walls and tubular geometry. Moreover, possibility of chemical functionalization of CNTs enables multi-functional probes. In this dissertation, novel nanofluidic instruments that have nanostructured carbon tips will be presented along with techniques that utilize the exceptional physical properties of carbon nanotubes, to take miniature biomedical instrumentation to the next level. New methods for fabricating the probes were rigorously developed and their operation was extensively studied. The devices were mechanically robust and were used to inject liquids to a single cell, detect electrochemical signals and enable surface enhanced Raman spectroscopy (SERS) while inducing minimal harm to the cell. Particular attention was focused on the CVD process-which was used to deposit carbon, fluid flow through the nanotubes, and separation of chemical species (atto-liter chromatography) at the nanometer scale that

  19. A route to brightly fluorescent carbon nanotubes for near-infrared imaging in mice

    Science.gov (United States)

    Welsher, Kevin; Liu, Zhuang; Sherlock, Sarah P.; Robinson, Joshua Tucker; Chen, Zhuo; Daranciang, Dan; Dai, Hongjie

    2009-11-01

    The near-infrared photoluminescence intrinsic to semiconducting single-walled carbon nanotubes is ideal for biological imaging owing to the low autofluorescence and deep tissue penetration in the near-infrared region beyond 1 µm. However, biocompatible single-walled carbon nanotubes with high quantum yield have been elusive. Here, we show that sonicating single-walled carbon nanotubes with sodium cholate, followed by surfactant exchange to form phospholipid-polyethylene glycol coated nanotubes, produces in vivo imaging agents that are both bright and biocompatible. The exchange procedure is better than directly sonicating the tubes with the phospholipid-polyethylene glycol, because it results in less damage to the nanotubes and improves the quantum yield. We show whole-animal in vivo imaging using an InGaAs camera in the 1-1.7 µm spectral range by detecting the intrinsic near-infrared photoluminescence of the `exchange' single-walled carbon nanotubes at a low dose (17 mg l-1 injected dose). The deep tissue penetration and low autofluorescence background allowed high-resolution intravital microscopy imaging of tumour vessels beneath thick skin.

  20. 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 gelators. We have fabricated the first 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.