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Sample records for carbon nanotube fiber

  1. Carbon nanotube fiber spun from wetted ribbon

    Science.gov (United States)

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

    2014-04-29

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

  2. 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.

  3. Fabrication of Microscale Carbon Nanotube Fibers

    Directory of Open Access Journals (Sweden)

    Gengzhi Sun

    2012-01-01

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

  4. Carbon composites composites with carbon fibers, nanofibers, and nanotubes

    CERN Document Server

    Chung, Deborah D L

    2017-01-01

    Carbon Composites: Composites with Carbon Fibers, Nanofibers, and Nanotubes, Second Edition, provides the reader with information on a wide range of carbon fiber composites, including polymer-matrix, metal-matrix, carbon-matrix, ceramic-matrix and cement-matrix composites. In contrast to other books on composites, this work emphasizes materials rather than mechanics. This emphasis reflects the key role of materials science and engineering in the development of composite materials. The applications focus of the book covers both the developing range of structural applications for carbon fiber composites, including military and civil aircraft, automobiles and construction, and non-structural applications, including electromagnetic shielding, sensing/monitoring, vibration damping, energy storage, energy generation, and deicing. In addition to these new application areas, new material in this updated edition includes coverage of cement-matrix composites, carbon nanofibers, carbon matrix precursors, fiber surface ...

  5. 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

  6. Carbon Nanotube Fiber Pretreatments for Electrodeposition of Copper

    OpenAIRE

    Hannula, Pyry-Mikko; Junnila, Minttu; Janas, Dawid; Aromaa, Jari; Forsén, Olof; Lundström, Mari

    2018-01-01

    There is increasing interest towards developing carbon nanotube-copper (CNT-Cu) composites due to potentially improved properties. Carbon nanotube macroscopic materials typically exhibit high resistivity, low electrochemical reactivity, and the presence of impurities, which impede its use as a substrate for electrochemical deposition of metals. In this research, different CNT fiber pretreatment methods, such as heat treatment, immersion in Watts bath, anodization, and exposure to boric acid (...

  7. Electrophoretic deposition of carbon nanotubes on a carbon fiber surface with different index graphitization

    International Nuclear Information System (INIS)

    Almeida, E.C.; Baldan, M.R.; Ferreira, N.G.; Edwards, E.R.

    2009-01-01

    Full text: The purpose of this work is to examine the electrophoretic deposition of carbon nanotubes powder on carbon fibers, produced at different heat treatments temperatures. Besides, a systematic study of the effects of graphitization index from substrate on the structure and morphology of CNTs has been available. Carbon fibers were produced from polyacrylonitrile at three different heat treatments temperatures, 1000, 1500 and 2000 deg C. The carbon fibers microstructure or its graphitization index may be controlled by the heat treatments temperatures. The electrophoretic deposition of carbon nanotubes was obtained with the powder of carbon nanotubes dispersed in water by ultrasonication to obtain dispersions of 0.05 mg/mL. The carbon fibers were immersed in the nanotube dispersion, and a positive potential of 10 V/cm was applied. Morphology and microstructure of carbon nanotubes on carbon fibers were obtained by scanning electron microscopy, Raman spectroscopy and X-ray photoelectron spectroscopy. (author)

  8. 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

  9. Cohesive zone model of carbon nanotube-coated carbon fiber/polyester composites

    International Nuclear Information System (INIS)

    Agnihotri, Prabhat Kamal; Kar, Kamal K; Basu, Sumit

    2012-01-01

    It has been previously reported that the average properties of carbon nanotube-coated carbon fiber/polyester multiscale composites critically depend on the length and density of nanotubes on the fiber surface. In this paper the effect of nanotube length and density on the interfacial properties of the carbon nanotube-coated carbon fiber–polymer interface has been studied using shear lag and a cohesive zone model. The latter model incorporates frictional sliding after complete debonding between the fiber and matrix and has been developed to quantify the effect of nanotube coating on various interfacial characterizing parameters. Our numerical results indicate that fibers with an optimal coverage and length of nanotubes significantly increase the interfacial strength and friction between the fiber and polymer. However, they also embrittle the interface compared with bare fibers. (paper)

  10. Preparation and characterization of carbon nanotube-hybridized carbon fiber to reinforce epoxy composite

    International Nuclear Information System (INIS)

    An, Feng; Lu, Chunxiang; Li, Yonghong; Guo, Jinhai; Lu, Xiaoxuan; Lu, Huibin; He, Shuqing; Yang, Yu

    2012-01-01

    Highlights: → CNTs were uniformly grown onto the carbon fibers. → No obvious mechanical properties of carbon fiber were observed after CNT growth. → The IFSS of multiscale epoxy composite was measured by single fiber pull-out tests. → Observing fractography of composite, the fracture modes of CNTs were discussed. -- Abstract: The multiscale carbon nanotube-hybridized carbon fiber was prepared by a newly developed aerosol-assisted chemical vapour deposition. Scanning electron microscopy and transmission electron microscope were carried out to characterize this multiscale material. Compared with the original carbon fibers, the fabrication of this hybrid fiber resulted in an almost threefold increase of BET surface area to reach 2.22 m 2 /g. Meanwhile, there was a slight degradation of fiber tensile strength within 10%, while the fiber modulus was not significantly affected. The interfacial shearing strength of a carbon fiber-reinforced polymer composite with carbon nanotube-hybridized carbon fiber and an epoxy matrix was determined from the single fiber pull-out tests of microdroplet composite. Due to an efficient increase of load transfer at the fiber/matrix interfaces, the interracial shear strength of composite reinforced by carbon nanotube-hybridized carbon fiber is almost 94% higher than that of one reinforced by the original carbon fiber. Based on the fractured morphologies of the composites, the interfacial reinforcing mechanisms were discussed through proposing different types of carbon nanotube fracture modes along with fiber pulling out from epoxy composites.

  11. The Carbon Nanotube Fibers for Optoelectric Conversion and Energy Storage

    Directory of Open Access Journals (Sweden)

    Yongfeng Luo

    2014-01-01

    Full Text Available This review summarizes recent studies on carbon nanotube (CNT fibers for weavable device of optoelectric conversion and energy storage. The intrinsic properties of individual CNTs make the CNT fibers ideal candidates for optoelectric conversion and energy storage. Many potential applications such as solar cell, supercapacitor, and lithium ion battery have been envisaged. The recent advancement in CNT fibers for optoelectric conversion and energy storage and the current challenge including low energy conversion efficiency and low stability and future direction of the energy fiber have been finally summarized in this paper.

  12. Nanocomposite fibers and film containing polyolefin and surface-modified carbon nanotubes

    Science.gov (United States)

    Chu,Benjamin; Hsiao, Benjamin S.

    2010-01-26

    Methods for modifying carbon nanotubes with organic compounds are disclosed. The modified carbon nanotubes have enhanced compatibility with polyolefins. Nanocomposites of the organo-modified carbon nanotubes and polyolefins can be used to produce both fibers and films having enhanced mechanical and electrical properties, especially the elongation-to-break ratio and the toughness of the fibers and/or films.

  13. Multifunctional Hybrid Carbon Nanotube/Carbon Fiber Polymer Composites

    Science.gov (United States)

    Kang, Jin Ho; Cano, Roberto J.; Ratcliffe, James G.; Luong, Hoa; Grimsley, Brian W.; Siochi, Emilie J.

    2016-01-01

    For aircraft primary structures, carbon fiber reinforced polymer (CFRP) composites possess many advantages over conventional aluminum alloys due to their light weight, higher strengthand stiffness-to-weight ratio, and low life-cycle maintenance costs. However, the relatively low electrical and thermal conductivities of CFRP composites fail to provide structural safety in certain operational conditions such as lightning strikes. Despite several attempts to solve these issues with the addition of carbon nanotubes (CNT) into polymer matrices, and/or by interleaving CNT sheets between conventional carbon fiber (CF) composite layers, there are still interfacial problems that exist between CNTs (or CF) and the resin. In this study, hybrid CNT/CF polymer composites were fabricated by interleaving layers of CNT sheets with Hexcel® IM7/8852 prepreg. Resin concentrations from 1 wt% to 50 wt% were used to infuse the CNT sheets prior to composite fabrication. The interlaminar properties of the resulting hybrid composites were characterized by mode I and II fracture toughness testing (double cantilever beam and end-notched flexure test). Fractographical analysis was performed to study the effect of resin concentration. In addition, multi-directional physical properties like thermal conductivity of the orthotropic hybrid polymer composite were evaluated. Interleaving CNT sheets significantly improved the in-plane (axial and perpendicular direction of CF alignment) thermal conductivity of the hybrid composite laminates by 50 - 400%.

  14. Thermal Properties of Hybrid Carbon Nanotube/Carbon Fiber Polymer

    Science.gov (United States)

    Kang, Jin Ho; Cano, Roberto J.; Luong, Hoa; Ratcliffe, James G.; Grimsley, Brian W.; Siochi, Emilie J.

    2016-01-01

    Carbon fiber reinforced polymer (CFRP) composites possess many advantages for aircraft structures over conventional aluminum alloys: light weight, higher strength- and stiffness-to-weight ratio, and low life-cycle maintenance costs. However, the relatively low thermal and electrical conductivities of CFRP composites are deficient in providing structural safety under certain operational conditions such as lightning strikes. One possible solution to these issues is to interleave carbon nanotube (CNT) sheets between conventional carbon fiber (CF) composite layers. However, the thermal and electrical properties of the orthotropic hybrid CNT/CF composites have not been fully understood. In this study, hybrid CNT/CF polymer composites were fabricated by interleaving layers of CNT sheets with Hexcel (Registered Trademark) IM7/8852 prepreg. The CNT sheets were infused with a 5% solution of a compatible epoxy resin prior to composite fabrication. Orthotropic thermal and electrical conductivities of the hybrid polymer composites were evaluated. The interleaved CNT sheets improved the in-plane thermal conductivity of the hybrid composite laminates by about 400% and the electrical conductivity by about 3 orders of magnitude.

  15. 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.

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

    International Nuclear Information System (INIS)

    Ku-Herrera, J.J.; Avilés, F.; Nistal, A.; Cauich-Rodríguez, J.V.; Rubio, F.; Rubio, J.; Bartolo-Pérez, P.

    2015-01-01

    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

  17. 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.

  18. Fabrication of highly conductive carbon nanotube fibers for electrical application

    International Nuclear Information System (INIS)

    Guo, Fengmei; Li, Can; Wei, Jinquan; Xu, Ruiqiao; Zhang, Zelin; Cui, Xian; Wang, Kunlin; Wu, Dehai

    2015-01-01

    Carbon nanotubes (CNTs) have great potential for use as electrical wires because of their outstanding electrical and mechanical properties. Here, we fabricate lightweight CNT fibers with electrical conductivity as high as that of stainless steel from macroscopic CNT films by drawing them through diamond wire-drawing dies. The entangled CNT bundles are straightened by suffering tension, which improves the alignment of the fibers. The loose fibers are squeezed by the diamond wire-drawing dies, which reduces the intertube space and contact resistance. The CNT fibers prepared by drawing have an electrical conductivity as high as 1.6 × 10 6 s m −1 . The fibers are very stable when kept in the air and under cyclic tensile test. A prototype of CNT motor is demonstrated by replacing the copper wires with the CNT fibers. (paper)

  19. Multifunctional Next Generation Carbon Nanotube Super Fibers

    National Research Council Canada - National Science Library

    Ait-Haddou, Hassan

    2005-01-01

    The goal of this program was to produce continuous strong CNT-based fibers. The production of continuous fibers was met and we have matched 2/3 of the strength of what has been previously reported with CNT-PAN fibers...

  20. Films, Buckypapers and Fibers from Clay, Chitosan and Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Marc in het Panhuis

    2011-04-01

    Full Text Available The mechanical and electrical characteristics of films, buckypapers and fiber materials from combinations of clay, carbon nanotubes (CNTs and chitosan are described. The rheological time-dependent characteristics of clay are maintained in clay–carbon nanotube–chitosan composite dispersions. It is demonstrated that the addition of chitosan improves their mechanical characteristics, but decreases electrical conductivity by three-orders of magnitude compared to clay–CNT materials. We show that the electrical response upon exposure to humid atmosphere is influenced by clay-chitosan interactions, i.e., the resistance of clay–CNT materials decreases, whereas that of clay–CNT–chitosan increases.

  1. Mechanical characterization of epoxy composite with multiscale reinforcements: Carbon nanotubes and short carbon fibers

    International Nuclear Information System (INIS)

    Rahmanian, S.; Suraya, A.R.; Shazed, M.A.; Zahari, R.; Zainudin, E.S.

    2014-01-01

    Highlights: • Multiscale composite was prepared by incorporation of carbon nanotubes and fibers. • Carbon nanotubes were also grown on short carbon fibers to enhance stress transfer. • Significant improvements were achieved in mechanical properties of composites. • Synergic effect of carbon nanotubes and fibers was demonstrated. - Abstract: Carbon nanotubes (CNT) and short carbon fibers were incorporated into an epoxy matrix to fabricate a high performance multiscale composite. To improve the stress transfer between epoxy and carbon fibers, CNT were also grown on fibers through chemical vapor deposition (CVD) method to produce CNT grown short carbon fibers (CSCF). Mechanical characterization of composites was performed to investigate the synergy effects of CNT and CSCF in the epoxy matrix. The multiscale composites revealed significant improvement in elastic and storage modulus, strength as well as impact resistance in comparison to CNT–epoxy or CSCF–epoxy composites. An optimum content of CNT was found which provided the maximum stiffness and strength. The synergic reinforcing effects of combined fillers were analyzed on the fracture surface of composites through optical and scanning electron microscopy (SEM)

  2. Nano-yarn carbon nanotube fiber based enzymatic glucose biosensor

    International Nuclear Information System (INIS)

    Zhu Zhigang; Burugapalli, Krishna; Moussy, Francis; Song, Wenhui; Li Yali; Zhong Xiaohua

    2010-01-01

    A novel brush-like electrode based on carbon nanotube (CNT) nano-yarn fiber has been designed for electrochemical biosensor applications and its efficacy as an enzymatic glucose biosensor demonstrated. The CNT nano-yarn fiber was spun directly from a chemical-vapor-deposition (CVD) gas flow reaction using a mixture of ethanol and acetone as the carbon source and an iron nano-catalyst. The fiber, 28 μm in diameter, was made of bundles of double walled CNTs (DWNTs) concentrically compacted into multiple layers forming a nano-porous network structure. Cyclic voltammetry study revealed a superior electrocatalytic activity for CNT fiber compared to the traditional Pt-Ir coil electrode. The electrode end tip of the CNT fiber was freeze-fractured to obtain a unique brush-like nano-structure resembling a scale-down electrical 'flex', where glucose oxidase (GOx) enzyme was immobilized using glutaraldehyde crosslinking in the presence of bovine serum albumin (BSA). An outer epoxy-polyurethane (EPU) layer was used as semi-permeable membrane. The sensor function was tested against a standard reference electrode. The sensitivities, linear detection range and linearity for detecting glucose for the miniature CNT fiber electrode were better than that reported for a Pt-Ir coil electrode. Thermal annealing of the CNT fiber at 250 deg. C for 30 min prior to fabrication of the sensor resulted in a 7.5 fold increase in glucose sensitivity. The as-spun CNT fiber based glucose biosensor was shown to be stable for up to 70 days. In addition, gold coating of the electrode connecting end of the CNT fiber resulted in extending the glucose detection limit to 25 μM. To conclude, superior efficiency of CNT fiber for glucose biosensing was demonstrated compared to a traditional Pt-Ir sensor.

  3. Nano-yarn carbon nanotube fiber based enzymatic glucose biosensor

    Science.gov (United States)

    Zhu, Zhigang; Song, Wenhui; Burugapalli, Krishna; Moussy, Francis; Li, Ya-Li; Zhong, Xiao-Hua

    2010-04-01

    A novel brush-like electrode based on carbon nanotube (CNT) nano-yarn fiber has been designed for electrochemical biosensor applications and its efficacy as an enzymatic glucose biosensor demonstrated. The CNT nano-yarn fiber was spun directly from a chemical-vapor-deposition (CVD) gas flow reaction using a mixture of ethanol and acetone as the carbon source and an iron nano-catalyst. The fiber, 28 µm in diameter, was made of bundles of double walled CNTs (DWNTs) concentrically compacted into multiple layers forming a nano-porous network structure. Cyclic voltammetry study revealed a superior electrocatalytic activity for CNT fiber compared to the traditional Pt-Ir coil electrode. The electrode end tip of the CNT fiber was freeze-fractured to obtain a unique brush-like nano-structure resembling a scale-down electrical 'flex', where glucose oxidase (GOx) enzyme was immobilized using glutaraldehyde crosslinking in the presence of bovine serum albumin (BSA). An outer epoxy-polyurethane (EPU) layer was used as semi-permeable membrane. The sensor function was tested against a standard reference electrode. The sensitivities, linear detection range and linearity for detecting glucose for the miniature CNT fiber electrode were better than that reported for a Pt-Ir coil electrode. Thermal annealing of the CNT fiber at 250 °C for 30 min prior to fabrication of the sensor resulted in a 7.5 fold increase in glucose sensitivity. The as-spun CNT fiber based glucose biosensor was shown to be stable for up to 70 days. In addition, gold coating of the electrode connecting end of the CNT fiber resulted in extending the glucose detection limit to 25 µM. To conclude, superior efficiency of CNT fiber for glucose biosensing was demonstrated compared to a traditional Pt-Ir sensor.

  4. 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)

  5. 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.

  6. 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

    2014-01-01

    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. PMID:28344254

  7. Carbon nanotube fiber mats for microbial fuel cell electrodes.

    Science.gov (United States)

    Delord, Brigitte; Neri, Wilfrid; Bertaux, Karen; Derre, Alain; Ly, Isabelle; Mano, Nicolas; Poulin, Philippe

    2017-11-01

    Novel carbon nanotube based electrodes of microbial fuel cells (MFC) have been developed. MFC is a promising technology for the wastewater treatment and the production of electrical energy from redox reactions of natural substrates. Performances of such bio-electrochemical systems depend critically on the structure and properties of the electrodes. The presently developed materials are made by weaving fibers solely comprised of carbon nanotubes. They exhibit a large scale porosity controlled by the weaving process. This porosity allows an easy colonization by electroactive bacteria. In addition, the fibers display a nanostructuration that promotes excellent growth and adhesion of the bacteria at the surface of the electrodes. This unique combination of large scale porosity and nanostructuration allows the present electrodes to perform better than carbon reference. When used as anode in a bioelectrochemical reactor in presence of Geobacter sulfurreducens bacteria, the present electrodes show a maximal current density of about 7.5mA/cm 2 . Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Carbon Nanotubes Growth by CVD on Graphite Fibers

    Science.gov (United States)

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

    2002-01-01

    Due to the superior electrical and mechanical properties of carbon nanotubes (CNT), synthesizing CNT on various substances for electronics devices and reinforced composites have been engaged in many efforts for applications. This presentation will illustrate CNT synthesized on graphite fibers by thermal CVD. On the fiber surface, iron nanoparticles as catalysts for CNT growth are coated. The growth temperature ranges from 600 to 1000 C and the pressure ranges from 100 Torr to one atmosphere. Methane and hydrogen gases with methane content of 10% to 100% are used for the CNT synthesis. At high growth temperatures (greater than or equal to 900 C), the rapid inter-diffusion of the transition metal iron on the graphite surface results in the rough fiber surface without any CNT grown on it. When the growth temperature is relative low (650-800 C), CNT with catalytic particles on the nanotube top ends are fabricated on the graphite surface. (Methane and hydrogen gases with methane content of 10% to 100% are used for the CNT synthesis.) (By measuring the samples) Using micro Raman spectroscopy in the breath mode region, single-walled or multi-walled CNT (MWCNT), depending on growth concentrations, are found. Morphology, length and diameter of these MWCNT are determined by scanning electron microscopy and Raman spectroscopy. The detailed results of syntheses and characterizations will be discussed in the presentation.

  9. Carbon Nanotube Chopped Fiber for Enhanced Properties in Additive Manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Menchhofer, Paul A [ORNL; Lindahl, John M [ORNL; JohnsonPhD, DR Joseph E. [Nanocomp Technologies, Inc.

    2016-06-06

    Nanocomp Technologies, Inc. is working with Oak Ridge National Laboratory to develop carbon nanotube (CNT) composite materials and evaluate their use in additive manufacturing (3D printing). The first phase demonstrated feasibility and improvements for carbon nanotube (CNT)- acrylonitrile butadiene styrene (ABS) composite filaments use in additive manufacturing, with potential future work centering on further improvements. By focusing the initial phase on standard processing methods (developed mainly for the incorporation of carbon fibers in ABS) and characterization techniques, a basis of knowledge for the incorporation of CNTs in ABS was learned. The ability to understand the various processing variables is critical to the successful development of these composites. From the degradation effects on ABS (caused by excessive temperatures), to the length of time the ABS is in the melt state, to the order of addition of constituents, and also to the many possible mixing approaches, a workable flow sequence that addresses each processing step is critical to the final material properties. Although this initial phase could not deal with each of these variables in-depth, a future study is recommended that will build on the lessons learned for this effort.

  10. Enhancement of the in-plane shear properties of carbon fiber composites containing carbon nanotube mats

    Science.gov (United States)

    Kim, Hansang

    2015-01-01

    The in-plane shear property of carbon fiber laminates is one of the most important structural features of aerospace and marine structures. Fiber-matrix debonding caused by in-plane shear loading is the major failure mode of carbon fiber composites because of the stress concentration at the interfaces. In this study, carbon nanotube mats (CNT mat) were incorporated in two different types of carbon fiber composites. For the case of woven fabric composites, mechanical interlocking between the CNTs and the carbon fibers increased resistance to shear failure. However, not much improvement was observed for the prepreg composites as a result of incorporation of the CNT mats. The reinforcement mechanism of the CNT mat layer was investigated by a fractographic study using scanning electron microscopy. In addition, the CNT mat was functionalized by three different methods and the effectiveness of the functionalization methods was determined and the most appropriate functionalization method for the CNT mat was air oxidation.

  11. Deposition of carbon nanotubes onto aramid fibers using as-received and chemically modified fibers

    International Nuclear Information System (INIS)

    Rodríguez-Uicab, O.; Avilés, F.; Gonzalez-Chi, P.I; Canché-Escamilla, G.; Duarte-Aranda, S.; Yazdani-Pedram, M.; Toro, P.; Gamboa, F.; Mazo, M.A.; Nistal, A.; Rubio, J.

    2016-01-01

    Highlights: • The surface of aramid fibers was functionalized by two acid treatments. • The treatment based on HNO_3/H_2SO_4 reduced the mechanical properties of the fibers. • CNTs were deposited on the aramid fibers, reaching electrical conductivity. • Homogeneous CNT distribution was achieved by using pristine fibers or chlorosulfonic acid. - Abstract: Multiwall carbon nanotubes (MWCNTs) oxidized by an acid treatment were deposited on the surface of as-received commercial aramid fibers containing a surface coating (“sizing”), and fibers modified by either a chlorosulfonic treatment or a mixture of nitric and sulfuric acids. The surface of the aramid fiber activated by the chemical treatments presents increasing density of CO, COOH and OH functional groups. However, these chemical treatments reduced the tensile mechanical properties of the fibers, especially when the nitric and sulfuric acid mixture was used. Characterization of the MWCNTs deposited on the fiber surface was conducted by scanning electron microscopy, Raman spectroscopy mapping and X-ray photoelectron spectroscopy. These characterizations showed higher areal concentration and more homogeneous distribution of MWCNTs over the aramid fibers for as-received fibers and for those modified with chlorosulfonic acid, suggesting the existence of interaction between the oxidized MWCNTs and the fiber coating. The electrical resistance of the MWCNT-modified aramid yarns comprising ∼1000 individual fibers was in the order of MΩ/cm, which renders multifunctional properties.

  12. Deposition of carbon nanotubes onto aramid fibers using as-received and chemically modified fibers

    Energy Technology Data Exchange (ETDEWEB)

    Rodríguez-Uicab, O. [Centro de Investigación Científica de Yucatán A.C., Unidad de Materiales, Calle 43 No.130, Col. Chuburna 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. Chuburna de Hidalgo, C.P. 97200 Mérida, Yucatán (Mexico); Gonzalez-Chi, P.I; Canché-Escamilla, G.; Duarte-Aranda, S. [Centro de Investigación Científica de Yucatán A.C., Unidad de Materiales, Calle 43 No.130, Col. Chuburna de Hidalgo, C.P. 97200 Mérida, Yucatán (Mexico); Yazdani-Pedram, M. [Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, S. Livingstone 1007, Independencia, Santiago (Chile); Toro, P. [Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Av. Beauchef 850, Santiago (Chile); Gamboa, F. [Centro de Investigacion y de Estudios Avanzados del IPN, Unidad Mérida, Depto. de Física Aplicada, Km. 6 Antigua Carretera a Progreso, 97310 Mérida, Yucatán (Mexico); Mazo, M.A.; Nistal, A.; Rubio, J. [Instituto de Cerámica y Vidrio (ICV-CSIC), Kelsen 5, 28049 Madrid (Spain)

    2016-11-01

    Highlights: • The surface of aramid fibers was functionalized by two acid treatments. • The treatment based on HNO{sub 3}/H{sub 2}SO{sub 4} reduced the mechanical properties of the fibers. • CNTs were deposited on the aramid fibers, reaching electrical conductivity. • Homogeneous CNT distribution was achieved by using pristine fibers or chlorosulfonic acid. - Abstract: Multiwall carbon nanotubes (MWCNTs) oxidized by an acid treatment were deposited on the surface of as-received commercial aramid fibers containing a surface coating (“sizing”), and fibers modified by either a chlorosulfonic treatment or a mixture of nitric and sulfuric acids. The surface of the aramid fiber activated by the chemical treatments presents increasing density of CO, COOH and OH functional groups. However, these chemical treatments reduced the tensile mechanical properties of the fibers, especially when the nitric and sulfuric acid mixture was used. Characterization of the MWCNTs deposited on the fiber surface was conducted by scanning electron microscopy, Raman spectroscopy mapping and X-ray photoelectron spectroscopy. These characterizations showed higher areal concentration and more homogeneous distribution of MWCNTs over the aramid fibers for as-received fibers and for those modified with chlorosulfonic acid, suggesting the existence of interaction between the oxidized MWCNTs and the fiber coating. The electrical resistance of the MWCNT-modified aramid yarns comprising ∼1000 individual fibers was in the order of MΩ/cm, which renders multifunctional properties.

  13. Microfluidic Actuation of Carbon Nanotube Fibers for Neural Recordings

    Science.gov (United States)

    Vercosa, Daniel G.

    Implantable devices to record and stimulate neural circuits have led to breakthroughs in neuroscience; however, technologies capable of electrical recording at the cellular level typically rely on rigid metals that poorly match the mechanical properties of soft brain tissue. As a result these electrodes often cause extensive acute and chronic injury, leading to short electrode lifetime. Recently, flexible electrodes such as Carbon Nanotube fibers (CNTf) have emerged as an attractive alternative to conventional electrodes and studies have shown that these flexible electrodes reduce neuro-inflammation and increase the quality and longevity of neural recordings. Insertion of these new compliant electrodes, however, remains challenge. The stiffening agents necessary to make the electrodes rigid enough to be inserted increases device footprint, which exacerbates brain damage during implantation. To overcome this challenge we have developed a novel technology to precisely implant and actuate high-performance, flexible carbon nanotube fiber (CNTf) microelectrodes without using a stiffening agents or shuttles. Instead, our technology uses drag forces within a microfluidic device to drive electrodes into tissue while minimizing the amount of fluid that is ejected into the tissue. In vitro experiments in brain phantoms, show that microfluidic actuated CNTf can be implanted at least 4.5 mm depth with 30 microm precision, while keeping the total volume of fluid ejected below 0.1 microL. As proof of concept, we inserted CNTfs in the small cnidarian Hydra littoralis and observed compound action potentials corresponding to contractions and in agreement with the literature. Additionally, brain slices extracted from transgenic mice were used to show that our device can be used to record spontaneous and light evoked activity from the cortex and deep brain regions such as the thalamic reticular nucleus (TRN). Overall our microfluidic actuation technology provides a platform for

  14. Carbon Nanotubes and Carbon Nanotube Fiber Sensors: Growth, Processing and Characterization

    Science.gov (United States)

    Zhao, Haibo

    With multiple outstanding properties, such as high Young's modulus, high strength, good thermal conductivity and electrical conductivity, carbon nanotube (CNT) has been considered as a new generation of material that has many potential applications in many fields. One obstacle that stands in the way of applying CNTs in the real world is the limited growth length. Catalyst instability is one of the many factors that cause the stops of CNT growth. In this research, intermetalic Fe-Zr catalyst was used to grow millimeter long CNT arrays. The Fe-Zr particles enabled the growth of 1.7 millimeter long carbon nanotube arrays in 45 minutes. A comparison with pure Fe catalyst indicated that adding Zr to iron can stabilize the Fe catalyst at the CNT growth temperature and moderate its reactivity. In future, when CNTs are largely used in industrial, mass production of CNTs at a low cost is vital for market competition. In many current CNT growth methods, a process of depositing a thin catalyst film on top of Al 2O3 film on a piece of silicon wafer is required. Thus the size of CNT samples is limited by the size of the largest silicon wafer currently available, which is 8 inch in diameter. In this study, FeCl2 powders were used as the catalyst to grow CNT arrays not only on traditional silicon substrates but also on quartz substrates and carbon sheets. This unique method does not require the thin film deposition step, which shortens the time used for each batch of CNT growth. The simplicity of this method allows an easy scale-up for mass production of CNTs with a low cost. In order to improve this method, HCl was used to assist the CNT growth. HCl was added via flowing a small amount of C2H2 thorough a bubbuler where HCl solution was contained. With the assistance of HCl, CNT growth could be extended to 1 hour. 3 mm tall non-spinnable arrays and 2 mm tall spinnable arrays were produced using this method. With the increasing use of composite materials, real time health

  15. Enhanced electrochemical activity using vertically aligned carbon nanotube electrodes grown on carbon fiber

    Directory of Open Access Journals (Sweden)

    Evandro Augusto de Morais

    2011-09-01

    Full Text Available Vertically aligned carbon nanotubes were successfully grown on flexible carbon fibers by plasma enhanced chemical vapor deposition. The diameter of the CNT is controllable by adjusting the thickness of the catalyst Ni layer deposited on the fiber. Vertically aligned nanotubes were grown in a Plasma Enhanced Chemical Deposition system (PECVD at a temperature of 630 ºC, d.c. bias of -600 V and 160 and 68 sccm flow of ammonia and acetylene, respectively. Using cyclic voltammetry measurements, an increase of the surface area of our electrodes, up to 50 times higher, was observed in our samples with CNT. The combination of VACNTs with flexible carbon fibers can have a significant impact on applications ranging from sensors to electrodes for fuel cells.

  16. Coaxial Thermoplastic Elastomer-Wrapped Carbon Nanotube Fibers for Deformable and Wearable Strain Sensors

    KAUST Repository

    Zhou, Jian; Xu, Xuezhu; Xin, Yangyang; Lubineau, Gilles

    2018-01-01

    performances in these design requirements. Here, achieving highly stretchable and sensitive strain sensors by using a coaxial structure, prepared via coaxial wet spinning of thermoplastic elastomer-wrapped carbon nanotube fibers, is proposed. The sensors attain

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

    International Nuclear Information System (INIS)

    Deng, Chao; Jiang, Jianjun; Liu, Fa; Fang, Liangchao; Wang, Junbiao; Li, Dejia; Wu, Jianjun

    2015-01-01

    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

  18. Enhanced performance of electrospun carbon fibers modified with carbon nanotubes: promising electrodes for enzymatic biofuel cells.

    Science.gov (United States)

    Engel, A Both; Cherifi, A; Tingry, S; Cornu, D; Peigney, A; Laurent, Ch

    2013-06-21

    New nanostructured electrodes, promising for the production of clean and renewable energy in biofuel cells, were developed with success. For this purpose, carbon nanofibers were produced by the electrospinning of polyacrylonitrile solution followed by convenient thermal treatments (stabilization followed by carbonization at 1000, 1200 and 1400° C), and carbon nanotubes were adsorbed on the surfaces of the fibers by a dipping method. The morphology of the developed electrodes was characterized by several techniques (SEM, Raman spectroscopy, electrical conductivity measurement). The electrochemical properties were evaluated through cyclic voltammetry, where the influence of the carbonization temperature of the fibers and the beneficial contribution of the carbon nanotubes were observed through the reversibility and size of the redox peaks of K3Fe(CN)6 versus Ag/AgCl. Subsequently, redox enzymes were immobilized on the electrodes and the electroreduction of oxygen to water was realized as a test of their efficiency as biocathodes. Due to the fibrous and porous structure of these new electrodes, and to the fact that carbon nanotubes may have the ability to promote electron transfer reactions of redox biomolecules, the new electrodes developed were capable of producing higher current densities than an electrode composed only of electrospun carbon fibers.

  19. A 66 fs highly stable single wall carbon nanotube mode locked fiber laser

    International Nuclear Information System (INIS)

    Yu, Zhenhua; Zhang, Xiao; Dong, Xinzheng; Tian, Jinrong; Song, Yanrong; Wang, Yonggang

    2014-01-01

    We demonstrate a highly stable mode locked fiber laser based on single wall carbon nanotubes. The mode locking is achieved by the evanescent field interaction of the propagating light with a single wall carbon nanotube saturable absorber in a microfiber. The pulse width is 66 fs, which, to the best of our knowledge, is the shortest pulse achieved in a carbon nanotube mode locked fiber laser. The maximum average output power is 26 mW, which is about 20 times larger than that of a typical carbon nanotube mode locked fiber laser. The center of the wavelength is 1555 nm, with 54 nm spectral width. The repetition rate is 146 MHz. To investigate the laser’s stability, the output pulses are monitored for 120 h and there is no significant degradation of the laser spectral width or shape. (paper)

  20. Hybrid Carbon Fibers/Carbon Nanotubes Structures for Next Generation Polymeric Composites

    Directory of Open Access Journals (Sweden)

    M. Al-Haik

    2010-01-01

    Full Text Available Pitch-based carbon fibers are commonly used to produce polymeric carbon fiber structural composites. Several investigations have reported different methods for dispersing and subsequently aligning carbon nanotubes (CNTs as a filler to reinforce polymer matrix. The significant difficulty in dispersing CNTs suggested the controlled-growth of CNTs on surfaces where they are needed. Here we compare between two techniques for depositing the catalyst iron used toward growing CNTs on pitch-based carbon fiber surfaces. Electrochemical deposition of iron using pulse voltametry is compared to DC magnetron iron sputtering. Carbon nanostructures growth was performed using a thermal CVD system. Characterization for comparison between both techniques was compared via SEM, TEM, and Raman spectroscopy analysis. It is shown that while both techniques were successful to grow CNTs on the carbon fiber surfaces, iron sputtering technique was capable of producing more uniform distribution of iron catalyst and thus multiwall carbon nanotubes (MWCNTs compared to MWCNTs grown using the electrochemical deposition of iron.

  1. Real time sensing of structural glass fiber reinforced composites by using embedded PVA - carbon nanotube fibers

    Directory of Open Access Journals (Sweden)

    Marioli-Riga Z.

    2010-06-01

    Full Text Available Polyvinyl alcohol - carbon nanotube (PVA-CNT fibers had been embedded to glass fiber reinforced polymers (GFRP for the structural health monitoring of the composite material. The addition of the conductive PVA-CNT fiber to the nonconductive GFRP material aimed to enhance its sensing ability by means of the electrical resistance measurement method. The test specimen’s response to mechanical load and the in situ PVA-CNT fiber’s electrical resistance measurements were correlated for sensing and damage monitoring purposes. The embedded PVA-CNT fiber worked as a sensor in GFRP coupons in tensile loadings. Sensing ability of the PVA-CNT fibers was also demonstrated on an integral composite structure. PVA-CNT fiber near the fracture area of the structure recorded very high values when essential damage occurred to the structure. A finite element model of the same structure was developed to predict axial strains at locations of the integral composite structure where the fibers were embedded. The predicted FEA strains were correlated with the experimental measurements from the PVA-CNT fibers. Calculated and experimental values were in good agreement, thus enabling PVA-CNT fibers to be used as strain sensors.

  2. Effect of carbon nanotubes upon emissions from cutting and sanding carbon fiber-epoxy composites

    Energy Technology Data Exchange (ETDEWEB)

    Heitbrink, William A. [LMK OSH Consulting LLC (United States); Lo, Li-Ming, E-mail: LLo@cdc.gov [Centers for Disease Control and Prevention (CDC), Division of Applied Research and Technology, National Institute for Occupational Safety and Health (NIOSH) (United States)

    2015-08-15

    Carbon nanotubes (CNTs) are being incorporated into structural composites to enhance material strength. During fabrication or repair activities, machining nanocomposites may release CNTs into the workplace air. An experimental study was conducted to evaluate the emissions generated by cutting and sanding on three types of epoxy-composite panels: Panel A containing graphite fibers, Panel B containing graphite fibers and carbon-based mat, and Panel C containing graphite fibers, carbon-based mat, and multi-walled CNTs. Aerosol sampling was conducted with direct-reading instruments, and filter samples were collected for measuring elemental carbon (EC) and fiber concentrations. Our study results showed that cutting Panel C with a band saw did not generate detectable emissions of fibers inspected by transmission electron microscopy but did increase the particle mass, number, and EC emission concentrations by 20–80 % compared to Panels A and B. Sanding operation performed on two Panel C resulted in fiber emission rates of 1.9 × 10{sup 8} and 2.8 × 10{sup 6} fibers per second (f/s), while no free aerosol fibers were detected from sanding Panels A and B containing no CNTs. These free CNT fibers may be a health concern. However, the analysis of particle and EC concentrations from these same samples cannot clearly indicate the presence of CNTs, because extraneous aerosol generation from machining the composite epoxy material increased the mass concentrations of the EC.

  3. Effect of carbon nanotubes upon emissions from cutting and sanding carbon fiber-epoxy composites

    International Nuclear Information System (INIS)

    Heitbrink, William A.; Lo, Li-Ming

    2015-01-01

    Carbon nanotubes (CNTs) are being incorporated into structural composites to enhance material strength. During fabrication or repair activities, machining nanocomposites may release CNTs into the workplace air. An experimental study was conducted to evaluate the emissions generated by cutting and sanding on three types of epoxy-composite panels: Panel A containing graphite fibers, Panel B containing graphite fibers and carbon-based mat, and Panel C containing graphite fibers, carbon-based mat, and multi-walled CNTs. Aerosol sampling was conducted with direct-reading instruments, and filter samples were collected for measuring elemental carbon (EC) and fiber concentrations. Our study results showed that cutting Panel C with a band saw did not generate detectable emissions of fibers inspected by transmission electron microscopy but did increase the particle mass, number, and EC emission concentrations by 20–80 % compared to Panels A and B. Sanding operation performed on two Panel C resulted in fiber emission rates of 1.9 × 10 8 and 2.8 × 10 6 fibers per second (f/s), while no free aerosol fibers were detected from sanding Panels A and B containing no CNTs. These free CNT fibers may be a health concern. However, the analysis of particle and EC concentrations from these same samples cannot clearly indicate the presence of CNTs, because extraneous aerosol generation from machining the composite epoxy material increased the mass concentrations of the EC

  4. Multiscale Hybrid Micro-Nanocomposites Based on Carbon Nanotubes and Carbon Fibers

    Directory of Open Access Journals (Sweden)

    Fawad Inam

    2010-01-01

    Full Text Available Amino-modified double wall carbon nanotube (DWCNT-NH2/carbon fiber (CF/epoxy hybrid micro-nanocomposite laminates were prepared by a resin infusion technique. DWCNT-NH2/epoxy nanocomposites and carbon fiber/epoxy microcomposites were made for comparison. Morphological analysis of the hybrid composites was performed using field emission scanning electron microscope. A good dispersion at low loadings of carbon nanotubes (CNTs in epoxy matrix was achieved by a bath ultrasonication method. Mechanical characterization of the hybrid micro-nanocomposites manufactured by a resin infusion process included three-point bending, mode I interlaminar toughness, dynamic mechanical analysis, and drop-weight impact testing. The addition of small amounts of CNTs (0.025, 0.05, and 0.1 wt% to epoxy resins for the fabrication of multiscale carbon fiber composites resulted in a maximum enhancement in flexural modulus by 35%, a 5% improvement in flexural strength, a 6% improvement in absorbed impact energy, and 23% decrease in the mode I interlaminar toughness. Hybridization of carbon fiber-reinforced epoxy using CNTs resulted in a reduction in and dampening characteristics, presumably as a result of the presence of micron-sized agglomerates.

  5. Thermal characteristics of carbon fiber reinforced epoxy containing multi-walled carbon nanotubes

    Directory of Open Access Journals (Sweden)

    Jin-woo Lee

    2018-06-01

    Full Text Available The material with irregular atomic structures such as polymer material exhibits low thermal conductivity because of the complex structural properties. Even materials with same atomic configurations, thermal conductivity may be different based on their structural properties. It is expected that nanoparticles with conductivity will change non-conductive polymer base materials to electrical conductors, and improve the thermal conductivity even with extremely small filling amount. Nano-composite materials contain nanoparticles with a higher surface ratio which makes the higher interface percentage to the total surface of nanoparticles. Therefore, thermal resistance of the interface becomes a dominating factor determines the effective thermal conductivity in nano-composite materials. Carbon fiber has characteristic of resistance or magnetic induction and Also, Carbon nanotube (CNT has electronic and thermal property. It can be applied for heating system. These characteristic are used as heating composite. In this research, the exothermic characteristics of Carbon fiber reinforced composite added CNT were evaluated depend on CNT length and particle size. It was found that the CNT dispersed in the resin reduces the resistance between the interfaces due to the decrease in the total resistance of the heating element due to the addition of CNTs. It is expected to improve the life and performance of the carbon fiber composite material as a result of the heating element resulting from this paper. Keywords: Carbon Nanotube (CNT, Carbon Fiber Reinforcement Plastic (CFRP, Heater, Exothermic characteristics

  6. Carbon fiber/carbon nanotube reinforced hierarchical composites: Effect of CNT distribution on shearing strength

    DEFF Research Database (Denmark)

    Zhou, H. W.; Mishnaevsky, Leon; Yi, H. Y.

    2016-01-01

    The strength and fracture behavior of carbon fiber reinforced polymer composites with carbon nanotube (CNT) secondary reinforcement are investigated experimentally and numerically. Short Beam Shearing tests have been carried out, with SEM observations of the damage evolution in the composites. 3D...... CNT nanoreinforcement into the matrix and/or the sizing of carbon fiber/reinforced composites ensures strong increase of the composite strength. The effect of secondary CNTs reinforcement is strongest when some small addition of CNTs in the polymer matrix is complemented by the fiber sizing with high...... multiscale computational (FE) models of the carbon/polymer composite with varied CNT distributions have been developed and employed to study the effect of the secondary CNT reinforcement, its distribution and content on the strength and fracture behavior of the composites. It is shown that adding secondary...

  7. Development of Circular Disk Model for Polymeric Nanocomposites and Micromechanical Analysis of Residual Stresses in Reinforced Fibers with Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    A. R. Ghasemi

    2017-02-01

    Full Text Available In this study, Circular Disk Model (CDM has been developed to determine the residual stresses in twophase and three- phase unit cell. The two-phase unit cell is consisting of carbon fiber and matrix. The three-phase unit cell is consisting of carbon fiber, carbon nanotubes and matrix in which the carbon fiber is reinforced with the carbon nanotube using electrophoresis method. For different volume fractions of carbon nanotubes, thermal properties of the carbon fiber and carbon nanotube in different linear and lateral directions and also different placement conditions of carbon nanotubes have been considered. Also, residual stresses distribution in two and three phases has been studied, separately. Results of micromechanical analysis of residual stresses obtained from Finite Element Method and CDM, confirms the evaluation and development of three dimensional CDM.

  8. Application of Conductive Carbon Nanotube Fibers and Composites: Gas Sensor

    Science.gov (United States)

    2013-05-01

    changes in Raman spectroscopy data when single wall carbon nanotubes (SWNT) are immersed in various liquids, including common organics (12). In...Resistance -- (82) 2007 Su H2O MWNT PMMA, KOH Gas Impedance -- (83) 2011 Tang H2O MWNT PI Gas Resistance -- (84) 2003 Wang H2O2, NADH SWNT

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

    International Nuclear Information System (INIS)

    Gomathi, A.; Ramya Harika, M.; Rao, C.N.R.

    2008-01-01

    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 3 BO 3 and urea, followed by a heat treatment at 1000 deg. C in a N 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

  10. Effect of doping of multi-walled carbon nanotubes on phenolic based carbon fiber reinforced nanocomposites

    International Nuclear Information System (INIS)

    Saeed, Sadaf; Hakeem, Saira; Faheem, Muhammad; Alvi, Rashid Ahmed; Farooq, Khawar; Hussain, Syed Tajammul; Ahmad, Shahid Nisar

    2013-01-01

    We report on the effect of multi-walled carbon nanotubes (MWCNTs) on different properties of phenolic resin. A low content of MWCNTs (∼ 0.05 wt%) was mixed in phenolic resin and a stable dispersion was achieved by ultrasonication, followed by melt mixing. After curing the characterization of these composites was done by using scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and Fourier transform infra-red spectroscopy (FTIR). The thermal and ablative properties of carbon fiber reinforced MWCNTs-phenolic nanocomposites were also studied. The addition of MWCNTs showed improvement in thermal stability and ablation properties.

  11. Conductivity and Ambient Stability of Halogen-Doped Carbon Nanotube Fibers

    Science.gov (United States)

    Gaier, J. R.; Chirino, C. M.; Chen, M.; Waters, D. L.; Tran, Mai Kim; Headrick, R.; Young, C. C.; Tsentalovich, D.; Whiting, B.; Pasquali, M.; hide

    2014-01-01

    Carbon nanotube fibers were fabricated using a variety of spinning conditions and post-spinning processing with the goal of creating a high-conductivity yet environmentally stable fiber. These fiber variants were then doped with bromine, iodine, iodine chloride, or iodine bromide and their electrical and microstructural properties were characterized. Environmentally stable compounds were synthesized with electrical conductivity greater than 50,000 Scm.

  12. Solid-State Spun Fibers from 1 mm Long Carbon Nanotube Forests Synthesized by Water-Assisted Chemical Vapor Deposition

    Science.gov (United States)

    Zhang, Shanju; Zhu, Lingbo; Minus, Marilyn L.; Chae, han Gi; Jagannathan, Sudhakar; Wong, Ching-Ping; Kowalik, Janusz; Roberson, Luke B.; Kumar, Satish

    2007-01-01

    In this work, we report continuous carbon nanotube fibers dry-drawn directly from water-assisted CVD grown forests with millimeter scale length. As-drawn nanotube fibers exist as aerogel and can be transformed into more compact fibers through twisting or densification with a volatile liquid. Nanotube fibers are characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Raman microscopy and wide-angle X-ray diffraction (WAXD). Mechanical behavior and electrical conductivity of the post-treated nanotube fibers are investigated.

  13. XPS analysis of the carbon fibers surface modified via HMDSO to carbon nanotube growth

    Energy Technology Data Exchange (ETDEWEB)

    Cardoso, L.D.R.; Gomes, M.C.B.; Trava-Airoldi, V.J.; Corat, E.J.; Lugo, D.C. [Instituto Nacional de Pesquisas Espaciais (INPE), Sao Jose dos Campos, SP (Brazil)

    2016-07-01

    Full text: Carbon fibers (CF) have been widely used to reinforce structural composites. Due to their strength-to-weight properties, CF composites are finding increased structural uses in areas such as aerospace, aeronautical, automobile and others. The strength of the fiber-resin interface bond has been found to be the limiting factor to the mechanical properties of CF-epoxy materials, due to their non-polar nature that limit the affinity of CF to bind chemically to any matrix. The growth of carbon nanotubes (CNTs) on the surface of CF is a promising approach for improving mechanical, electrical and thermal properties of structural composites. However growing CNTs on CF presents some obstacles, such as diffusion of metal catalyst particles on CF, uneven CNT growth and loss of mechanical properties of CF. To avoid the diffusion of catalyst particles we modified the CF surface with hexamethyldisiloxane (HMDSO) at low temperature (400 °C), also preventing the loss of mechanical properties and allowing uniform CNTs growth. We deposited CNTs via floating catalyst method, with ferrocene providing the catalyst particle and the oxidative dehydrogenation reaction of acetylene providing the carbon. The CF surface modification was analyzed via X-ray photoelectron spectroscopy (XPS) and CNTs growth via scanning electron microscopy with field emission gun. The XPS analysis showed that HMDSO promotes the binding of oxygen to carbon and silicon present on CF surface, the chemical modification of the surface of the CF enables the uniform growth of carbon nanotubes. (author)

  14. XPS analysis of the carbon fibers surface modified via HMDSO to carbon nanotube growth

    International Nuclear Information System (INIS)

    Cardoso, L.D.R.; Gomes, M.C.B.; Trava-Airoldi, V.J.; Corat, E.J.; Lugo, D.C.

    2016-01-01

    Full text: Carbon fibers (CF) have been widely used to reinforce structural composites. Due to their strength-to-weight properties, CF composites are finding increased structural uses in areas such as aerospace, aeronautical, automobile and others. The strength of the fiber-resin interface bond has been found to be the limiting factor to the mechanical properties of CF-epoxy materials, due to their non-polar nature that limit the affinity of CF to bind chemically to any matrix. The growth of carbon nanotubes (CNTs) on the surface of CF is a promising approach for improving mechanical, electrical and thermal properties of structural composites. However growing CNTs on CF presents some obstacles, such as diffusion of metal catalyst particles on CF, uneven CNT growth and loss of mechanical properties of CF. To avoid the diffusion of catalyst particles we modified the CF surface with hexamethyldisiloxane (HMDSO) at low temperature (400 °C), also preventing the loss of mechanical properties and allowing uniform CNTs growth. We deposited CNTs via floating catalyst method, with ferrocene providing the catalyst particle and the oxidative dehydrogenation reaction of acetylene providing the carbon. The CF surface modification was analyzed via X-ray photoelectron spectroscopy (XPS) and CNTs growth via scanning electron microscopy with field emission gun. The XPS analysis showed that HMDSO promotes the binding of oxygen to carbon and silicon present on CF surface, the chemical modification of the surface of the CF enables the uniform growth of carbon nanotubes. (author)

  15. Fiber-optic anemometer based on single-walled carbon nanotube coated tilted fiber Bragg grating.

    Science.gov (United States)

    Zhang, Yang; Wang, Fang; Liu, Zigeng; Duan, Zhihui; Cui, Wenli; Han, Jie; Gu, Yiying; Wu, Zhenlin; Jing, Zhenguo; Sun, Changsen; Peng, Wei

    2017-10-02

    In this work, a novel and simple optical fiber hot-wire anemometer based on single-walled carbon nanotubes (SWCNTs) coated tilted fiber Bragg grating (TFBG) is proposed and demonstrated. For the hot-wire wind speed sensor design, TFBG is an ideal in-fiber sensing structure due to its unique features. It is utilized as both light coupling and temperature sensing element without using any geometry-modified or uncommon fiber, which simplifies the sensor structure. To further enhance the thermal conversion capability, SWCNTs are coated on the surface of the TFBG instead of traditional metallic materials, which have excellent thermal characteristics. When a laser light is pumped into the sensor, the pump light propagating in the core will be easily coupled into cladding of the fiber via the TFBG and strongly absorbed by the SWCNTs thin film. This absorption acts like a hot-wire raising the local temperature of the fiber, which is accurately detected by the TFBG resonance shift. In the experiments, the sensor's performances were investigated and controlled by adjusting the inherent angle of the TFBG, the thickness of SWCNTs film, and the input power of the pump laser. It was demonstrated that the developed anemometer exhibited significant light absorption efficiency up to 93%, and the maximum temperature of the local area on the fiber was heated up to 146.1°C under the relatively low pump power of 97.76 mW. The sensitivity of -0.3667 nm/(m/s) at wind speed of 1.0 m/s was measured with the selected 12° TFBG and 1.6 μm film.

  16. Conduction noise absorption by fiber-reinforced epoxy composites with carbon nanotubes

    International Nuclear Information System (INIS)

    Lee, Ok Hyoung; Kim, Sung-Soo; Lim, Yun-Soo

    2011-01-01

    Nearly all electronic equipment is susceptible to malfunction as a result of electromagnetic interference. In this study, glass fiber, and carbon fiber as a type reinforcement and epoxy as a matrix material were used to fabricate composite materials. In an attempt to increase the conduction noise absorption, carbon nanotubes were grown on the surface of glass fibers and carbon fibers. A microstrip line with characteristic impedance of 50 Ω in connection with network analyzer was used to measure the conduction noise absorption. In comparing a glass fiber/epoxy composite with a GF-CNT/Ep composite, it was demonstrated that the CNTs significantly influence the noise absorption property mainly due to increase in electric conductivity. In the carbon fiber composites, however, the effectiveness of CNTs on the degree of electric conductivity is negligible, resulting in a small change in reflection and transmission of an electromagnetic wave. - Research Highlights: → In this study, glass fiber and carbon fiber as a type reinforcement and epoxy as a matrix material were used to fabricate composite materials. In an attempt to increase the conduction noise absorption, carbon nanotubes (CNTs) were grown on the surface of glass fibers and carbon fibers. A microstrip line with characteristic impedance of 50 Ω in connection with network analyzer was used to measure the conduction noise absorption. → In comparing a glass fiber/epoxy composite with a GF-CNT/Ep composite, it was demonstrated that the CNTs significantly influence the noise absorption property mainly due to increase in electric conductivity. In the carbon fiber composites, however, the effectiveness of CNTs on the degree of electric conductivity is negligible, resulting in a small change in reflection and transmission of an electromagnetic wave.

  17. Fiber Optic Chemical Nanosensors Based on Engineered Single-Walled Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    M. Consales

    2008-01-01

    Full Text Available In this contribution, a review of the development of high-performance optochemical nanosensors based on the integration of carbon nanotubes with the optical fiber technology is presented. The paper first provide an overview of the amazing features of carbon nanotubes and their exploitation as highly adsorbent nanoscale materials for gas sensing applications. Successively, the attention is focused on the operating principle, fabrication, and characterization of fiber optic chemosensors in the Fabry-Perot type reflectometric configuration, realized by means of the deposition of a thin layer of single-walled carbon nanotubes (SWCNTs upon the distal end of standard silica optical fibers. This is followed by an extensive review of the excellent sensing capabilities of the realized SWCNTs-based chemical nanosensors against volatile organic compounds and other pollutants in different environments (air and water and operating conditions (room temperature and cryogenic temperatures. The experimental results reported here reveal that ppm and sub-ppm chemical detection limits, low response times, as well as fast and complete recovery of the sensor responses have been obtained in most of the investigated cases. This evidences the great potentialities of the proposed photonic nanosensors based on SWCNTs to be successfully employed for practical environmental monitoring applications both in liquid and vapor phase as well as for space. Furthermore, the use of novel SWCNTs-based composites as sensitive fiber coatings is proposed to enhance the sensing performance and to improve the adhesion of carbon nanotubes to the fiber surface. Finally, new advanced sensing configurations based on the use of hollow-core optical fibers coated and partially filled by carbon nanotubes are also presented.

  18. Electrically conducting nanobiocomposites using carbon nanotubes and collagen waste fibers

    International Nuclear Information System (INIS)

    Meiyazhagan, Ashokkumar; Thangavel, Saravanamoorthy; Hashim, Daniel P.; Ajayan, Pulickel M.; Palanisamy, Thanikaivelan

    2015-01-01

    Electrically conducting hybrid biocomposite films were prepared using a simple and cost-effective method by incorporating different types of carbon nanotubes (XCNTs) viz., few walled carbon nanotube (FWCNT) and boron doped carbon nanotube (BCNT) into biopolymers. Collagen extracted from animal skin wastes was blended with guar gum and XCNTs in varying proportions to form flexible and electrically conducting hybrid films. We found that the electrical conductivity of both types of hybrid films increases radically as the XCNT loading increases. BCNT incorporated hybrid films show better electrical conductivity (3.0 × 10 −1 S/cm) than their FWCNT loaded counter parts (4.8 × 10 −4 S/cm) at a dosage of 2 wt.%. On the other hand, mechanical and other physical properties such as transparency, flexibility and surface smoothness of the developed hybrid films were affected as a function of XCNT concentration. We also demonstrated that the developed hybrid films lit up a LED lamp when inserted between batteries and the brightness of the emitted light depended on the XCNT loading. These results suggest a new way to transform an industrial biowaste into innovative advanced materials for applications in fields related to biomedicine, biosensors and electronics. - Highlights: • Hybrid nanobiocomposite films prepared using collagen, guar gum and CNTs. • Examined the effect of CNT doping on the properties of hybrid biocomposite films. • Higher CNT loading improved the conductivity radically, especially for BCNT. • The ability of developed hybrid films to lit up a LED lamp was demonstrated. • The results suggest a new way to transform biowaste into advanced materials

  19. Solid-state, polymer-based fiber solar cells with carbon nanotube electrodes.

    Science.gov (United States)

    Liu, Dianyi; Zhao, Mingyan; Li, Yan; Bian, Zuqiang; Zhang, Luhui; Shang, Yuanyuan; Xia, Xinyuan; Zhang, Sen; Yun, Daqin; Liu, Zhiwei; Cao, Anyuan; Huang, Chunhui

    2012-12-21

    Most previous fiber-shaped solar cells were based on photoelectrochemical systems involving liquid electrolytes, which had issues such as device encapsulation and stability. Here, we deposited classical semiconducting polymer-based bulk heterojunction layers onto stainless steel wires to form primary electrodes and adopted carbon nanotube thin films or densified yarns to replace conventional metal counter electrodes. The polymer-based fiber cells with nanotube film or yarn electrodes showed power conversion efficiencies in the range 1.4% to 2.3%, with stable performance upon rotation and large-angle bending and during long-time storage without further encapsulation. Our fiber solar cells consisting of a polymeric active layer sandwiched between steel and carbon electrodes have potential in the manufacturing of low-cost, liquid-free, and flexible fiber-based photovoltaics.

  20. Thermal characteristics of carbon fiber reinforced epoxy containing multi-walled carbon nanotubes

    Science.gov (United States)

    Lee, Jin-woo; Park, Soo-Jeong; Kim, Yun-hae; Riichi-Murakami

    2018-06-01

    The material with irregular atomic structures such as polymer material exhibits low thermal conductivity because of the complex structural properties. Even materials with same atomic configurations, thermal conductivity may be different based on their structural properties. It is expected that nanoparticles with conductivity will change non-conductive polymer base materials to electrical conductors, and improve the thermal conductivity even with extremely small filling amount. Nano-composite materials contain nanoparticles with a higher surface ratio which makes the higher interface percentage to the total surface of nanoparticles. Therefore, thermal resistance of the interface becomes a dominating factor determines the effective thermal conductivity in nano-composite materials. Carbon fiber has characteristic of resistance or magnetic induction and Also, Carbon nanotube (CNT) has electronic and thermal property. It can be applied for heating system. These characteristic are used as heating composite. In this research, the exothermic characteristics of Carbon fiber reinforced composite added CNT were evaluated depend on CNT length and particle size. It was found that the CNT dispersed in the resin reduces the resistance between the interfaces due to the decrease in the total resistance of the heating element due to the addition of CNTs. It is expected to improve the life and performance of the carbon fiber composite material as a result of the heating element resulting from this paper.

  1. Stretchable Fiber Supercapacitors with High Volumetric Performance Based on Buckled MnO2 /Oxidized Carbon Nanotube Fiber Electrodes.

    Science.gov (United States)

    Li, Mingyang; Zu, Mei; Yu, Jinshan; Cheng, Haifeng; Li, Qingwen

    2017-03-01

    A stretchable fiber supercapacitor (SC) based on buckled MnO 2 /oxidized carbon nanotube (CNT) fiber electrode is fabricated by a simple prestraining-then-buckling method. The prepared stretchable fiber SC has a specific volumetric capacitance up to 409.4 F cm -3 , which is 33 times that of the pristine CNT fiber based SC, and shows the outstanding stability and repeatability in performance as a stretchable SC. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Low-loss saturable absorbers based on tapered fibers embedded in carbon nanotube/polymer composites

    Science.gov (United States)

    Martinez, Amos; Al Araimi, Mohammed; Dmitriev, Artemiy; Lutsyk, Petro; Li, Shen; Mou, Chengbo; Rozhin, Alexey; Sumetsky, Misha; Turitsyn, Sergei

    2017-12-01

    The emergence of low-dimensional materials has opened new opportunities in the fabrication of compact nonlinear photonic devices. Single-walled carbon nanotubes were among the first of those materials to attract the attention of the photonics community owing to their high third order susceptibility, broadband operation, and ultrafast response. Saturable absorption, in particular, has become a widespread application for nanotubes in the mode-locking of a fiber laser where they are used as nonlinear passive amplitude modulators to initiate pulsed operation. Numerous approaches have been proposed for the integration of nanotubes in fiber systems; these can be divided into those that rely on direct interaction (where the nanotubes are sandwiched between fiber connectors) and those that rely on lateral interaction with the evanescence field of the propagating wave. Tapered fibers, in particular, offer excellent flexibility to adjust the nonlinearity of nanotube-based devices but suffer from high losses (typically exceeding 50%) and poor saturable to non-saturable absorption ratios (typically above 1:5). In this paper, we propose a method to fabricate carbon nanotube saturable absorbers with controllable saturation power, low-losses (as low as 15%), and large saturable to non-saturable loss ratios approaching 1:1. This is achieved by optimizing the procedure of embedding tapered fibers in low-refractive index polymers. In addition, this study sheds light in the operation of these devices, highlighting a trade-off between losses and saturation power and providing guidelines for the design of saturable absorbers according to their application.

  3. Low-loss saturable absorbers based on tapered fibers embedded in carbon nanotube/polymer composites

    Directory of Open Access Journals (Sweden)

    Amos Martinez

    2017-12-01

    Full Text Available The emergence of low-dimensional materials has opened new opportunities in the fabrication of compact nonlinear photonic devices. Single-walled carbon nanotubes were among the first of those materials to attract the attention of the photonics community owing to their high third order susceptibility, broadband operation, and ultrafast response. Saturable absorption, in particular, has become a widespread application for nanotubes in the mode-locking of a fiber laser where they are used as nonlinear passive amplitude modulators to initiate pulsed operation. Numerous approaches have been proposed for the integration of nanotubes in fiber systems; these can be divided into those that rely on direct interaction (where the nanotubes are sandwiched between fiber connectors and those that rely on lateral interaction with the evanescence field of the propagating wave. Tapered fibers, in particular, offer excellent flexibility to adjust the nonlinearity of nanotube-based devices but suffer from high losses (typically exceeding 50% and poor saturable to non-saturable absorption ratios (typically above 1:5. In this paper, we propose a method to fabricate carbon nanotube saturable absorbers with controllable saturation power, low-losses (as low as 15%, and large saturable to non-saturable loss ratios approaching 1:1. This is achieved by optimizing the procedure of embedding tapered fibers in low-refractive index polymers. In addition, this study sheds light in the operation of these devices, highlighting a trade-off between losses and saturation power and providing guidelines for the design of saturable absorbers according to their application.

  4. Sharp burnout failure observed in high current-carrying double-walled carbon nanotube fibers

    Science.gov (United States)

    Song, Li; Toth, Geza; Wei, Jinquan; Liu, Zheng; Gao, Wei; Ci, Lijie; Vajtai, Robert; Endo, Morinobu; Ajayan, Pulickel M.

    2012-01-01

    We report on the current-carrying capability and the high-current-induced thermal burnout failure modes of 5-20 µm diameter double-walled carbon nanotube (DWNT) fibers made by an improved dry-spinning method. It is found that the electrical conductivity and maximum current-carrying capability for these DWNT fibers can reach up to 5.9 × 105 S m - 1 and over 1 × 105 A cm - 2 in air. In comparison, we observed that standard carbon fiber tended to be oxidized and burnt out into cheese-like morphology when the maximum current was reached, while DWNT fiber showed a much slower breakdown behavior due to the gradual burnout in individual nanotubes. The electron microscopy observations further confirmed that the failure process of DWNT fibers occurs at localized positions, and while the individual nanotubes burn they also get aligned due to local high temperature and electrostatic field. In addition a finite element model was constructed to gain better understanding of the failure behavior of DWNT fibers.

  5. Electroadsorption desalination with carbon nanotube/PAN-based carbon fiber felt composites as electrodes.

    Science.gov (United States)

    Liu, Yang; Zhou, Junbo

    2014-01-01

    The chemical vapor deposition method is used to prepare CNT (carbon nanotube)/PCF (PAN-based carbon fiber felt) composite electrodes in this paper, with the surface morphology of CNT/PCF composites and electroadsorption desalination performance being studied. Results show such electrode materials with three-dimensional network nanostructures having a larger specific surface area and narrower micropore distribution, with a huge number of reactive groups covering the surface. Compared with PCF electrodes, CNT/PCF can allow for a higher adsorption and desorption rate but lower energy consumption; meanwhile, under the condition of the same voltage change, the CNT/PCF electrodes are provided with a better desalination effect. The study also found that the higher the original concentration of the solution, the greater the adsorption capacity and the lower the adsorption rate. At the same time, the higher the solution's pH, the better the desalting; the smaller the ions' radius, the greater the amount of adsorption.

  6. Bonding Characteristics of Macrosynthetic Fiber in Latex-Modified Fiber-Reinforced Cement Composites as a Function of Carbon Nanotube Content

    Directory of Open Access Journals (Sweden)

    Ji-Hong Jean

    2016-01-01

    Full Text Available The effect of carbon nanotube content (0, 0.5, 1.0, 1.5, and 2.0% of the cement weight on the bonding properties of macrosynthetic fiber in latex-modified hybrid fiber cement-based composites (LMHFRCCs was evaluated. The slump value, compressive strength, and bonding strength were measured for each LMHFRCC. As the carbon nanotube content increased to 1.5%, the bonding properties of the macrosynthetic fiber improved. However, the bonding performance deteriorated at a carbon nanotube content of 2.0%. A decrease in the fluidity of the mix negatively affected the dispersion of the nanotubes in the LMHFRCCs. The addition of carbon nanotubes also affected the relative bonding strength independently of the improvement in compressive strength. Microscopic analysis of the macrosynthetic fiber surfaces was used to understand changes in the bonding behavior.

  7. Coaxial Thermoplastic Elastomer-Wrapped Carbon Nanotube Fibers for Deformable and Wearable Strain Sensors

    KAUST Repository

    Zhou, Jian

    2018-01-22

    Highly conductive and stretchable fibers are crucial components of wearable electronics systems. Excellent electrical conductivity, stretchability, and wearability are required from such fibers. Existing technologies still display limited performances in these design requirements. Here, achieving highly stretchable and sensitive strain sensors by using a coaxial structure, prepared via coaxial wet spinning of thermoplastic elastomer-wrapped carbon nanotube fibers, is proposed. The sensors attain high sensitivity (with a gauge factor of 425 at 100% strain), high stretchability, and high linearity. They are also reproducible and durable. Their use as safe sensing components on deformable cable, expandable surfaces, and wearable textiles is demonstrated.

  8. Lignin-based carbon fibers: Carbon nanotube decoration and superior thermal stability

    KAUST Repository

    Xu, Xuezhu

    2014-08-23

    Lignin-based carbon fibers (CFs) decorated with carbon nanotubes (CNTs) were synthesized and their structure, thermal stability and wettability were systematically studied. The carbon fiber precursors were produced by electrospinning lignin/polyacrylonitrile solutions. CFs were obtained by pyrolyzing the precursors and CNTs were subsequently grown on the CFs to eventually achieve a CF–CNT hybrid structure. The processes of pyrolysis and CNT growth were conducted in a tube furnace using different conditions and the properties of the resultant products were studied and compared. The CF–CNT hybrid structure produced at 850 °C using a palladium catalyst showed the highest thermal stability, i.e., 98.3% residual weight at 950 °C. A mechanism for such superior thermal stability was postulated based on the results from X-ray diffraction, Raman spectroscopy, scanning and transmission electron microscopy, and electron energy loss spectroscopy analyses. The dense CNT decoration was found to increase the hydrophobicity of the CFs.

  9. Carbon Nanotube Sheet Scrolled Fiber Composite for Enhanced Interfacial Mechanical Properties

    Science.gov (United States)

    Kokkada Ravindranath, Pruthul

    The high tensile strength of Polymer Matrix Composites (PMC) is derived from the high tensile strength of the embedded carbon fibers. However, their compressive strength is significantly lower than their tensile strength, as they tend to fail through micro-buckling, under compressive loading. Fiber misalignment and the presence of voids created during the manufacturing processes, add to the further reduction in the compressive strength of the composites. Hence, there is more scope for improvement. Since, the matrix is primarily responsible for the shear load transfer and dictating the critical buckling load of the fibers by constraining the fibers from buckling, to improve the interfacial mechanical properties of the composite, it is important to modify the polymer matrix, fibers and/or the interface. In this dissertation, a novel approach to enhance the polymer matrix-fiber interface region has been discussed. This approach involves spiral wrapping carbon nanotube (CNT) sheet around individual carbon fiber or fiber tow, at room temperature at a prescribed wrapping angle (bias angle), and then embed the scrolled fiber in a resin matrix. The polymer infiltrates into the nanopores of the multilayer CNT sheet to form CNT/polymer nanocomposite surrounding fiber, and due to the mechanical interlocking, provides reinforcement to the interface region between fiber and polymer matrix. This method of nano-fabrication has the potential to improve the mechanical properties of the fiber-matrix interphase, without degrading the fiber properties. The effect of introducing Multi-Walled Carbon Nanotubes (MWNT) in the polymer matrix was studied by analyzing the atomistic model of the epoxy (EPON-862) and the embedded MWNTs. A multi-scale method was utilized by using molecular dynamics (MD) simulations on the nanoscale model of the epoxy with and without the MWNTs to calculate compressive strength of the composite and predict the enhancement in the composite material. The influence

  10. Electrochemically Active Polymeric Hollow Fibers based on Poly(ether- b -amide)/Carbon Nanotubes

    KAUST Repository

    Cuevas, Carolina

    2017-09-18

    A simple and effective method to incorporate catalytic activity to a hollow fiber membrane is reported. Polyetherimide hollow fiber membranes were coated with a solution containing carboxyl-functionalized multi-walled carbon nanotubes and poly(ether-b-amide). Electron microscopy images confirmed the presence of a layer of percolating carbon nanotubes on the surface of the membranes. Cyclic voltammetry and linear swept voltammetry experiments showed that these membranes are able to drive the reactions of hydrogen evolution, and oxygen reduction, making them a cheaper, and greener substitute for platinum based cathodes in microbial bioelectrochemical systems. Water flux and molecular weight cut off experiments indicated that the electrochemically active coating layer does not affect the ultrafiltration performance of the membrane.

  11. Electrochemically Active Polymeric Hollow Fibers based on Poly(ether- b -amide)/Carbon Nanotubes

    KAUST Repository

    Cuevas, Carolina; Kim, Dooli; Katuri, Krishna; Saikaly, Pascal; Nunes, Suzana Pereira

    2017-01-01

    A simple and effective method to incorporate catalytic activity to a hollow fiber membrane is reported. Polyetherimide hollow fiber membranes were coated with a solution containing carboxyl-functionalized multi-walled carbon nanotubes and poly(ether-b-amide). Electron microscopy images confirmed the presence of a layer of percolating carbon nanotubes on the surface of the membranes. Cyclic voltammetry and linear swept voltammetry experiments showed that these membranes are able to drive the reactions of hydrogen evolution, and oxygen reduction, making them a cheaper, and greener substitute for platinum based cathodes in microbial bioelectrochemical systems. Water flux and molecular weight cut off experiments indicated that the electrochemically active coating layer does not affect the ultrafiltration performance of the membrane.

  12. Three-Phase Carbon Fiber Amine Functionalized Carbon Nanotubes Epoxy Composite: Processing, Characterisation, and Multiscale Modeling

    Directory of Open Access Journals (Sweden)

    Kamal Sharma

    2014-01-01

    Full Text Available The present paper discusses the key issues of carbon nanotube (CNT dispersion and effect of functionalisation on the mechanical properties of multiscale carbon epoxy composites. In this study, CNTs were added in epoxy matrix and further reinforced with carbon fibres. Predetermined amounts of optimally amine functionalised CNTs were dispersed in epoxy matrix, and unidirectional carbon fiber laminates were produced. The effect of the presence of CNTs (1.0 wt% in the resin was reflected by pronounced increase in Young’s modulus, inter-laminar shear strength, and flexural modulus by 51.46%, 39.62%, and 38.04%, respectively. However, 1.5 wt% CNT loading in epoxy resin decreased the overall properties of the three-phase composites. A combination of Halpin-Tsai equations and micromechanics modeling approach was also used to evaluate the mechanical properties of multiscale composites and the differences between the predicted and experimental values are reported. These multiscale composites are likely to be used for potential missile and aerospace structural applications.

  13. Textile electrodes woven by carbon nanotube-graphene hybrid fibers for flexible electrochemical capacitors.

    Science.gov (United States)

    Cheng, Huhu; Dong, Zelin; Hu, Chuangang; Zhao, Yang; Hu, Yue; Qu, Liangti; Chen, Nan; Dai, Liming

    2013-04-21

    Functional graphene-based fibers are promising as new types of flexible building blocks for the construction of wearable architectures and devices. Unique one-dimensional (1D) carbon nanotubes (CNTs) and 2D graphene (CNT/G) hybrid fibers with a large surface area and high electrical conductivity have been achieved by pre-intercalating graphene fibers with Fe3O4 nanoparticles for subsequent CVD growth of CNTs. The CNT/G hybrid fibers can be further woven into textile electrodes for the construction of flexible supercapacitors with a high tolerance to the repeated bending cycles. Various other applications, such as catalysis, separation, and adsorption, can be envisioned for the CNT/G hybrid fibers.

  14. Polymer-derived ceramic composite fibers with aligned pristine multiwalled carbon nanotubes.

    Science.gov (United States)

    Sarkar, Sourangsu; Zou, Jianhua; Liu, Jianhua; Xu, Chengying; An, Linan; Zhai, Lei

    2010-04-01

    Polymer-derived ceramic fibers with aligned multiwalled carbon nanotubes (MWCNTs) are fabricated through the electrospinning of polyaluminasilazane solutions with well-dispersed MWCNTs followed by pyrolysis. Poly(3-hexylthiophene)-b-poly (poly (ethylene glycol) methyl ether acrylate) (P3HT-b-PPEGA), a conjugated block copolymer compatible with polyaluminasilazane, is used to functionalize MWCNT surfaces with PPEGA, providing a noninvasive approach to disperse carbon nanotubes in polyaluminasilazane chloroform solutions. The electrospinning of the MWCNT/polyaluminasilazane solutions generates polymer fibers with aligned MWCNTs where MWCNTs are oriented along the electrospun jet by a sink flow. The subsequent pyrolysis of the obtained composite fibers produces ceramic fibers with aligned MWCNTs. The study of the effect of polymer and CNT concentration on the fiber structures shows that the fiber size increases with the increment of polymer concentration, whereas higher CNT content in the polymer solutions leads to thinner fibers attributable to the increased conductivity. Both the SEM and TEM characterization of the polymer and ceramic fibers demonstrates the uniform orientation of CNTs along the fibers, suggesting excellent dispersion of CNTs and efficient CNT alignment via the electrospinning. The electrical conductivity of a ceramic fibers with 1.2% aligned MWCNTs is measured to be 1.58 x 10(-6) S/cm, which is more than 500 times higher than that of bulk ceramic (3.43 x 10(-9) S/cm). Such an approach provides a versatile method to disperse CNTs in preceramic polymer solutions and offers a new approach to integrate aligned CNTs in ceramics.

  15. Thermo-physical properties of epoxy nanocomposites reinforced by carbon nanotubes and vapor grown carbon fibers

    International Nuclear Information System (INIS)

    Miyagawa, Hiroaki; Rich, Michael J.; Drzal, Lawrence T.

    2006-01-01

    In this study, the thermo-physical properties of epoxy nanocomposites reinforced by fluorinated single wall carbon nanotubes (FSWCNT) and vapor grown carbon fibers (VGCF) were investigated. A sonication technique using a suspension of FSWCNT and VGCF in acetone was utilized to process nanocomposites in anhydride-cured epoxy. The viscoelastic properties of the nanocomposites were measured with dynamic mechanical analysis. The glass transition temperature decreased approximately 30 deg. C with an addition of 0.14 vol.% (0.2 wt.%) FSWCNT. The depression in T g is attributed to non-stoichiometric balance of the epoxy matrix caused by the fluorine on single wall carbon nanotubes. The correct amount of the anhydride curing agent needed to achieve stoichiometry was experimentally determined by DMA measurements. After adjusting the amount of the anhydride curing agent for stoichiometry, the storage modulus of the epoxy at room temperature increased 0.63 GPa with the addition of only 0.21 vol.% (0.30 wt.%) of FSWCNT, a 20% improvement compared with the anhydride-cured neat epoxy. For VGCF, the storage modulus at room temperature increased 0.48 GPa with the addition of only 0.94 vol.% (1.5 wt.%) and then reached a plateau for larger amounts of VGCF. To understand the influence of VGCF on thermo-physical properties, the microstructure of the nanocomposites was interrogated using transmission electron microscopy (TEM). This study discusses the chemical effects of fluorine on matrix properties and the effect of stoichiometric balance on the thermo-physical properties of nanocomposites

  16. Effects of surfactants on spinning carbon nanotube fibers by an electrophoretic method

    Directory of Open Access Journals (Sweden)

    Jun Ma, Jie Tang, Qian Cheng, Han Zhang, Norio Shinya and Lu-Chang Qin

    2010-01-01

    Full Text Available Thin fibers were spun from a colloidal solution of single-walled carbon nanotubes (SWNTs using an electrophoretic method. Sodium dodecylbenzenesulfonate (NaDDBS was chosen as a surfactant and showed good performance owing to its special chemical structure. The highest spinning velocity reached 0.5 mm s−1. The resulting SWNT fibers had a tensile strength of 400 MPa and a conductivity of 355 S cm−1. Their mechanical and electrical properties were markedly improved after adding NaDDBS as the dispersant in water.

  17. Enhanced CO2 Adsorption on Activated Carbon Fibers Grafted with Nitrogen-Doped Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Yu-Chun Chiang

    2017-05-01

    Full Text Available In this paper, multiscale composites formed by grafting N-doped carbon nanotubes (CNs on the surface of polyamide (PAN-based activated carbon fibers (ACFs were investigated and their adsorption performance for CO2 was determined. The spaghetti-like and randomly oriented CNs were homogeneously grown onto ACFs. The pre-immersion of cobalt(II ions for ACFs made the CNs grow above with a large pore size distribution, decreased the oxidation resistance, and exhibited different predominant N-functionalities after chemical vapor deposition processes. Specifically, the CNs grafted on ACFs with or without pre-immersion of cobalt(II ions were characterized by the pyridine-like structures of six-member rings or pyrrolic/amine moieties, respectively. In addition, the loss of microporosity on the specific surface area and pore volume exceeded the gain from the generation of the defects from CNs. The adsorption capacity of CO2 decreased gradually with increasing temperature, implying that CO2 adsorption was exothermic. The adsorption capacities of CO2 at 25 °C and 1 atm were between 1.53 and 1.92 mmol/g and the Freundlich equation fit the adsorption data well. The isosteric enthalpy of adsorption, implying physical adsorption, indicated that the growth of CNTs on the ACFs benefit CO2 adsorption.

  18. Investigation of Mechanical Properties and Morphology of Multi-Walled Carbon Nanotubes Reinforced Cellulose Acetate Fibers

    Directory of Open Access Journals (Sweden)

    Quazi Nahida Sultana

    2017-11-01

    Full Text Available Cellulose acetate (CA fibers were reinforced with multi-walled carbon nanotubes (MWCNTs at 0.5%, 1.0%, 1.5% and 2.0%. Yield strength, ultimate tensile strength, fracture strain and toughness of the nanocomposite fiber increased up to 1.5 wt. % of the carbon nanotube (CNT loading, however, further inclusion (2.0% of MWCNTs in CA decreased the mechanical properties. Experimental properties were also compared with analytical predictions using a Shear lag model for strength and the rule of mixture for modulus. A solution spinning process, coupled with sonication, mixing, and extrusion, was used to process the CNT-reinforced composite fiber. Scanning electron microscopy (SEM images of the cross sections of neat CA and CA-MWCNT fibers showed the formation of voids and irregular features. The enhanced interconnected fibrillation in the CNT-reinforced CA samples resulted in improved mechanical properties, which were observed by tensile testing. Fourier transform infrared spectroscopy (FTIR spectra showed the area under the curve for C–H bonding after the inclusion of CNT. There was no significant shift of wavenumber for the inclusion of MWCNT in the CA matrix, which indicates that the sonication process of the CNT-loaded solution did not degrade the CA bonding structure.

  19. Wet spinning of PVA composite fibers with a large fraction of multi-walled carbon nanotubes

    Directory of Open Access Journals (Sweden)

    Dengpan Lai

    2015-10-01

    Full Text Available PVA composites fibers with a large fraction of multi-walled carbon nanotubes modified by both covalent and non-covalent functionalization were produced by a wet-spinning process. Model XQ-1 tensile tester, thermogravimetric analysis, scanning electron microscopy, differential scanning calorimetry, and wide-angle X-ray diffraction were used to characterize the properties of PVA/MWNT composite fibers. The TGA results suggested that MWNTs content in composite fibers were ranged from 5.3 wt% to 27.6 wt%. The mechanical properties of PVA/MWNT composite fibers were obviously superior to pure PVA fiber. The Young׳s modulus of composite fibers enhanced with increasing the content of MWNTs, and it rised gradually from 6.7 GPa for the pure PVA fiber to 12.8 GPa for the composite fibers with 27.6 wt% MWNTs. Meanwhile, the tensile strength increased gradually from 0.39 GPa for the pure PVA fiber to 0.74 GPa for the composite fibers with 14.4 wt% MWNTs. Nevertheless, the tensile strength of the composite fibers decreased as the MWNTs content up to 27.6 wt%. SEM results indicated that the MWNTs homogeneously dispersed in the composite fibers, however some agglomerates also existed when the content of MWNTs reached 27.6 wt%. DSC results proved strong interfacial interaction between MWNTs and PVA chain, which benefited composite fibers in the efficient stress-transfer. WXAD characterization showed that the orientation of PVA molecules declined from 94.1% to 90.9% with the increasing of MWNTs content. The good dispersibility of MWNTs throughout PVA matrix and efficient stress-transfer between MWNTs and PVA matrix may contributed to significant enhancement in the mechanical properties.

  20. Adsorption of aromatic compounds by carbonaceous adsorbents: a comparative study on granular activated carbon, activated carbon fiber, and carbon nanotubes.

    Science.gov (United States)

    Zhang, Shujuan; Shao, Ting; Kose, H Selcen; Karanfil, Tanju

    2010-08-15

    Adsorption of three aromatic organic compounds (AOCs) by four types of carbonaceous adsorbents [a granular activated carbon (HD4000), an activated carbon fiber (ACF10), two single-walled carbon nanotubes (SWNT, SWNT-HT), and a multiwalled carbon nanotube (MWNT)] with different structural characteristics but similar surface polarities was examined in aqueous solutions. Isotherm results demonstrated the importance of molecular sieving and micropore effects in the adsorption of AOCs by carbonaceous porous adsorbents. In the absence of the molecular sieving effect, a linear relationship was found between the adsorption capacities of AOCs and the surface areas of adsorbents, independent of the type of adsorbent. On the other hand, the pore volume occupancies of the adsorbents followed the order of ACF10 > HD4000 > SWNT > MWNT, indicating that the availability of adsorption site was related to the pore size distributions of the adsorbents. ACF10 and HD4000 with higher microporous volumes exhibited higher adsorption affinities to low molecular weight AOCs than SWNT and MWNT with higher mesopore and macropore volumes. Due to their larger pore sizes, SWNTs and MWNTs are expected to be more efficient in adsorption of large size molecules. Removal of surface oxygen-containing functional groups from the SWNT enhanced adsorption of AOCs.

  1. Wavelength and pulse duration tunable ultrafast fiber laser mode-locked with carbon nanotubes

    OpenAIRE

    Li, Diao; Jussila, Henri; Wang, Yadong; Hu, Guohua; Albrow-Owen, Tom; C. T. Howe, Richard; Ren, Zhaoyu; Bai, Jintao; Hasan, Tawfique; Sun, Zhipei

    2018-01-01

    Ultrafast lasers with tunable parameters in wavelength and time domains are the choice of light source for various applications such as spectroscopy and communication. Here, we report a wavelength and pulse-duration tunable mode-locked Erbium doped fiber laser with single wall carbon nanotube-based saturable absorber. An intra-cavity tunable filter is employed to continuously tune the output wavelength for 34 nm (from 1525 nm to 1559 nm) and pulse duration from 545 fs to 6.1 ps, respectively....

  2. Stable optical soliton in the ring-cavity fiber system with carbon nanotube as saturable absorber

    Science.gov (United States)

    Li, Bang-Qing; Ma, Yu-Lan; Yang, Tie-Mei

    2018-01-01

    Main attention focuses on the theoretical study of the ring-cavity fiber laser system with carbon nanotubes (CNT) as saturable absorber (SA). The system is modelled as a non-standard Schrödinger equation with the coefficients blended real and imaginary numbers. New stable exact soliton solution is constructed by the bilinear transformation method for the system. The influences of the key parameters related to CNTs and SA on the optical pulse soliton are discussed in simulation. The soliton amplitude and phase can be tuned by choosing suitable parameters.

  3. Multifunctional fiber reinforced polymer composites using carbon and boron nitride nanotubes

    Science.gov (United States)

    Ashrafi, Behnam; Jakubinek, Michael B.; Martinez-Rubi, Yadienka; Rahmat, Meysam; Djokic, Drazen; Laqua, Kurtis; Park, Daesun; Kim, Keun-Su; Simard, Benoit; Yousefpour, Ali

    2017-12-01

    Recent progress in nanotechnology has made several nano-based materials available with the potential to address limitations of conventional fiber reinforced polymer composites, particularly in reference to multifunctional structures. Carbon nanotubes (CNTs) are the most prevalent case and offer amazing properties at the individual nanotube level. There are already a few high-profile examples of the use of CNTs in space structures to provide added electrical conductivity for static dissipation and electromagnetic shielding. Boron nitride nanotubes (BNNTs), which are structurally analogous to CNTs, also present a range of attractive properties. Like the more widely explored CNTs, individual BNNTs display remarkable mechanical properties and high thermal conductivity but with contrasting functional attributes including substantially higher thermal stability, high electrical insulation, polarizability, high neutron absorption and transparency to visible light. This presents the potential of employing either or both BNNTs and CNTs to achieve a range of lightweight, functional composites for space structures. Here we present the case for application of BNNTs, in addition to CNTs, in space structures and describe recent advances in BNNT production at the National Research Council Canada (NRC) that have, for the first time, provided sufficiently large quantities to enable commercialization of high-quality BNNTs and accelerate development of chemistry, composites and applications based on BNNTs. Early demonstrations showing the fabrication and limited structural testing of polymer matrix composites, including glass fiber-reinforced composite panels containing BNNTs will be discussed.

  4. Feeding Single-Walled Carbon Nanotubes or Graphene to Silkworms for Reinforced Silk Fibers.

    Science.gov (United States)

    Wang, Qi; Wang, Chunya; Zhang, Mingchao; Jian, Muqiang; Zhang, Yingying

    2016-10-12

    Silkworm silk is gaining significant attention from both the textile industry and research society because of its outstanding mechanical properties and lustrous appearance. The possibility of creating tougher silks attracts particular research interest. Carbon nanotubes and graphene are widely studied for their use as reinforcement. In this work, we report mechanically enhanced silk directly collected by feeding Bombyx mori larval silkworms with single-walled carbon nanotubes (SWNTs) and graphene. We found that parts of the fed carbon nanomaterials were incorporated into the as-spun silk fibers, whereas the others went into the excrement of silkworms. Spectroscopy study indicated that nanocarbon additions hindered the conformation transition of silk fibroin from random coil and α-helix to β-sheet, which may contribute to increased elongation at break and toughness modules. We further investigated the pyrolysis of modified silk, and a highly developed graphitic structure with obviously enhanced electrical conductivity was obtained through the introduction of SWNTs and graphene. The successful generation of these SWNT- or graphene-embedded silks by in vivo feeding is expected to open up possibilities for the large-scale production of high-strength silk fibers.

  5. The concept of a novel hybrid smart composite reinforced with radially aligned zigzag carbon nanotubes on piezoelectric fibers

    International Nuclear Information System (INIS)

    Ray, M C

    2010-01-01

    A new hybrid piezoelectric composite (HPZC) reinforced with zigzag single-walled carbon nanotubes (CNTs) and piezoelectric fibers is proposed. The novel constructional feature of this composite is that the uniformly aligned CNTs are radially grown on the surface of piezoelectric fibers. A micromechanics model is derived to estimate the effective piezoelectric and elastic properties. It is found that the effective piezoelectric coefficient e 31 of the proposed HPZC, which accounts for the in-plane actuation, is significantly higher than that of the existing 1-3 piezoelectric composite without reinforcement with carbon nanotubes and the previously reported hybrid piezoelectric composite (Ray and Batra 2009 ASME J. Appl. Mech. 76 034503)

  6. Thermal conductivity of high performance carbon nanotube yarn-like fibers

    Energy Technology Data Exchange (ETDEWEB)

    Mayhew, Eric; Prakash, Vikas, E-mail: vikas.prakash@case.edu [Department of Mechanical and Aerospace Engineering, Case Western Reserve University, Cleveland, Ohio 44106-7222 (United States)

    2014-05-07

    In the present paper, we present results of thermal conductivity measurements in free standing carbon nanotube (CNT) yarn-like fibers. The measurements are made using a T-type experimental configuration utilizing a Wollaston-wire hot probe inside a scanning electron microscope. In this technique, a suspended platinum wire is used both as a heater and a thermal sensor. A low frequency alternating current source is used to heat the probe wire while the third harmonic voltage across the wire is measured by a lock-in amplifier. The conductivity is deduced from an analytical model that relates the drop in the spatially averaged temperature of the wire to that of the sample. The average thermal conductivity of the neat CNT fibers and the CNT –polymer composite fibers is found to be 448 W/m-K and 225 W/m-K, respectively. These values for conductivity are amongst the highest measured for CNT yarn-like fibers fabricated using a dry spinning process from vertically aligned CNT arrays. The enhancement in thermal conductivity is understood to be due to an increase in the CNT fiber elastic stiffness during the draw and twist operations, lower CNT thermal contact resistance due to increase in CNT contact area, and better alignment of the CNT fibrils along the length of the fiber.

  7. Carbon fiber microelectrodes modified with carbon nanotubes as a new support for immobilization of glucose oxidase

    International Nuclear Information System (INIS)

    Wen, H.; Nallathambi, V.; Chakraborty, D.; Barton, S.C.

    2011-01-01

    Carboxylated carbon nanotubes were coated onto carbon microfiber electrodes to create a micron-scale bioelectrode. This material has a high surface area and can serve as a support for immobilization of enzymes such as glucose oxidase. A typical carbon nanotube loading of 13 μg cm -1 yields a coating thickness of 17 μm and a 2000-fold increase in surface capacitance. The modified electrode was further coated with a biocatalytic hydrogel composed of a conductive redox polymer, glucose oxidase, and a crosslinker to create a glucose bioelectrode. The current density on oxidation of glucose is 16.6 mA cm-2 at 0.5 V (vs. Ag/AgCl) in oxygen-free glucose solution. We consider this approach to be useful for designing and characterizing surface treatments for carbon mats and papers by mimicking their local microenvironment. (author)

  8. Continuous carbon nanotube reinforced composites.

    Science.gov (United States)

    Ci, L; Suhr, J; Pushparaj, V; Zhang, X; Ajayan, P M

    2008-09-01

    Carbon nanotubes are considered short fibers, and polymer composites with nanotube fillers are always analogues of random, short fiber composites. The real structural carbon fiber composites, on the other hand, always contain carbon fiber reinforcements where fibers run continuously through the composite matrix. With the recent optimization in aligned nanotube growth, samples of nanotubes in macroscopic lengths have become available, and this allows the creation of composites that are similar to the continuous fiber composites with individual nanotubes running continuously through the composite body. This allows the proper utilization of the extreme high modulus and strength predicted for nanotubes in structural composites. Here, we fabricate such continuous nanotube polymer composites with continuous nanotube reinforcements and report that under compressive loadings, the nanotube composites can generate more than an order of magnitude improvement in the longitudinal modulus (up to 3,300%) as well as damping capability (up to 2,100%). It is also observed that composites with a random distribution of nanotubes of same length and similar filler fraction provide three times less effective reinforcement in composites.

  9. Multi-pulsed intense electron beam emission from velvet, carbon fibers, carbon nano-tubes and dispenser cathodes

    International Nuclear Information System (INIS)

    Xia Liansheng; Yang Anmin; Chen Yi; Zhang Huang; Liu Xingguang; Li Jin; Jiang Xiaoguo; Zhang Kaizhi; Shi Jinshui; Deng Jianjun; Zhang Linwen

    2010-01-01

    The experimental results of studies of four kinds of cathode emitting intense electron beams are demonstrated under multi-pulsed mode based on an experimental setup including two multi-pulse high voltage sources. The tested cathodes include velvet, carbon fibers, carbon nano-tubes (CNTs) and dispenser cathodes. The results indicate that all four are able to emit multi-pulsed beams. For velvet, carbon fiber and CNTs, the electron induced cathode plasma emission may be the main process and this means that there are differences in beam parameters from pulse to pulse. For dispenser cathodes tested in the experiment, although there is a little difference from pulse to pulse for some reason, thermal-electric field emission may be the main process. (authors)

  10. Modified resistivity-strain behavior through the incorporation of metallic particles in conductive polymer composite fibers containing carbon nanotubes

    NARCIS (Netherlands)

    Lin, L.; Deng, H.; Gao, X.; Zhang, S.M.; Bilotti, E.; Peijs, A.A.J.M.; Fu, Q.

    2013-01-01

    Eutectic metal particles and carbon nanotubes are incorporated into a thermoplastic polyurethane matrix through a simple but efficient method, melt compounding, to tune the resistivity-strain behavior of conductive polymer composite (CPC) fibers. Such a combination of conductive fillers is rarely

  11. Application of carbon nanotubes to topographical resolution enhancement of tapered fiber scanning near field optical microscopy probes

    Science.gov (United States)

    Huntington, S. T.; Jarvis, S. P.

    2003-05-01

    Scanning near field optical microscopy (SNOM) probes are typically tapered optical fibers with metallic coatings. The tip diameters are generally in excess of 300 nm and thus provide poor topographical resolution. Here we report on the attachment multiwalled carbon nanotubes to the probes in order to substantially enhance the topographical resolution, without adversely affecting the optical resolution.

  12. Using in-situ polymerization of conductive polymers to enhance the electrical properties of solution-processed carbon nanotube films and fibers.

    Science.gov (United States)

    Allen, Ranulfo; Pan, Lijia; Fuller, Gerald G; Bao, Zhenan

    2014-07-09

    Single-walled carbon nanotubes/polymer composites typically have limited conductivity due to a low concentration of nanotubes and the insulating nature of the polymers used. Here we combined a method to align carbon nanotubes with in-situ polymerization of conductive polymer to form composite films and fibers. Use of the conducting polymer raised the conductivity of the films by 2 orders of magnitude. On the other hand, CNT fiber formation was made possible with in-situ polymerization to provide more mechanical support to the CNTs from the formed conducting polymer. The carbon nanotube/conductive polymer composite films and fibers had conductivities of 3300 and 170 S/cm, respectively. The relatively high conductivities were attributed to the polymerization process, which doped both the SWNTs and the polymer. In-situ polymerization can be a promising solution-processable method to enhance the conductivity of carbon nanotube films and fibers.

  13. Electrical and Self-Sensing Properties of Ultra-High-Performance Fiber-Reinforced Concrete with Carbon Nanotubes

    OpenAIRE

    You, Ilhwan; Yoo, Doo-Yeol; Kim, Soonho; Kim, Min-Jae; Zi, Goangseup

    2017-01-01

    This study examined the electrical and self-sensing capacities of ultra-high-performance fiber-reinforced concrete (UHPFRC) with and without carbon nanotubes (CNTs). For this, the effects of steel fiber content, orientation, and pore water content on the electrical and piezoresistive properties of UHPFRC without CNTs were first evaluated. Then, the effect of CNT content on the self-sensing capacities of UHPFRC under compression and flexure was investigated. Test results indicated that higher ...

  14. Stretchable, Weavable Coiled Carbon Nanotube/MnO2/Polymer Fiber Solid-State Supercapacitors

    Science.gov (United States)

    Choi, Changsoon; Kim, Shi Hyeong; Sim, Hyeon Jun; Lee, Jae Ah; Choi, A Young; Kim, Youn Tae; Lepró, Xavier; Spinks, Geoffrey M.; Baughman, Ray H.; Kim, Seon Jeong

    2015-01-01

    Fiber and yarn supercapacitors that are elastomerically deformable without performance loss are sought for such applications as power sources for wearable electronics, micro-devices, and implantable medical devices. Previously reported yarn and fiber supercapacitors are expensive to fabricate, difficult to upscale, or non-stretchable, which limits possible use. The elastomeric electrodes of the present solid-state supercapacitors are made by using giant inserted twist to coil a nylon sewing thread that is helically wrapped with a carbon nanotube sheet, and then electrochemically depositing pseudocapacitive MnO2 nanofibers. These solid-state supercapacitors decrease capacitance by less than 15% when reversibly stretched by 150% in the fiber direction, and largely retain capacitance while being cyclically stretched during charge and discharge. The maximum linear and areal capacitances (based on active materials) and areal energy storage and power densities (based on overall supercapacitor dimensions) are high (5.4 mF/cm, 40.9 mF/cm2, 2.6 μWh/cm2 and 66.9 μW/cm2, respectively), despite the engineered superelasticity of the fiber supercapacitor. Retention of supercapacitor performance during large strain (50%) elastic deformation is demonstrated for supercapacitors incorporated into the wristband of a glove. PMID:25797351

  15. Stretchable, weavable coiled carbon nanotube/MnO2/polymer fiber solid-state supercapacitors.

    Science.gov (United States)

    Choi, Changsoon; Kim, Shi Hyeong; Sim, Hyeon Jun; Lee, Jae Ah; Choi, A Young; Kim, Youn Tae; Lepró, Xavier; Spinks, Geoffrey M; Baughman, Ray H; Kim, Seon Jeong

    2015-03-23

    Fiber and yarn supercapacitors that are elastomerically deformable without performance loss are sought for such applications as power sources for wearable electronics, micro-devices, and implantable medical devices. Previously reported yarn and fiber supercapacitors are expensive to fabricate, difficult to upscale, or non-stretchable, which limits possible use. The elastomeric electrodes of the present solid-state supercapacitors are made by using giant inserted twist to coil a nylon sewing thread that is helically wrapped with a carbon nanotube sheet, and then electrochemically depositing pseudocapacitive MnO2 nanofibers. These solid-state supercapacitors decrease capacitance by less than 15% when reversibly stretched by 150% in the fiber direction, and largely retain capacitance while being cyclically stretched during charge and discharge. The maximum linear and areal capacitances (based on active materials) and areal energy storage and power densities (based on overall supercapacitor dimensions) are high (5.4 mF/cm, 40.9 mF/cm(2), 2.6 μWh/cm(2) and 66.9 μW/cm(2), respectively), despite the engineered superelasticity of the fiber supercapacitor. Retention of supercapacitor performance during large strain (50%) elastic deformation is demonstrated for supercapacitors incorporated into the wristband of a glove.

  16. Smart carbon nanotube/fiber and PVA fiber-reinforced composites for stress sensing and chloride ion detection

    Science.gov (United States)

    Hoheneder, Joshua

    Fiber reinforced composites (FRC) with polyvinyl alcohol (PVA) fibers and carbon nanofibers (CNF) had an excellent flexural strength in excess of 18.5 MPa compared to reference samples of 15.8 MPa. It was found that the developed, depending on applied stress and exposure to chloride solutions, composites exhibit some electrical conductivity, from 4.20×10 -4 (Ω-1m-1 to 4.13×10 -4 Ω-1m-1. These dependences can be characterized by piezioresistive and chemoresistive coefficients demonstrating that the material possesses self-sensing capabilities. The sensitivity to stain and chloride solutions can be enhanced by incorporating small amounts of carbon nanofibers (CNF) or carbon nanotube (CNT) into composite structure. Conducted research has demonstrated a strong dependency of electrical properties of composite on crack formation in moist environments. The developed procedure is scalable for industrial application in concrete structures that require nondestructive stress monitoring, integrity under high service loads and stability in harsh environments.

  17. Designing of epoxy composites reinforced with carbon nanotubes grown carbon fiber fabric for improved electromagnetic interference shielding

    Directory of Open Access Journals (Sweden)

    B. P. Singh

    2012-06-01

    Full Text Available In this letter, we report preparation of strongly anchored multiwall carbon nanotubes (MWCNTs carbon fiber (CF fabric preforms. These preforms were reinforced in epoxy resin to make multi scale composites for microwave absorption in the X-band (8.2-12.4GHz. The incorporation of MWCNTs on the carbon fabric produced a significant enhancement in the electromagnetic interference shielding effectiveness (EMI-SE from −29.4 dB for CF/epoxy-composite to −51.1 dB for CF-MWCNT/epoxy multiscale composites of 2 mm thickness. In addition to enhanced EMI-SE, interlaminar shear strength improved from 23 MPa for CF/epoxy-composites to 50 MPa for multiscale composites indicating their usefulness for making structurally strong microwave shields.

  18. Mode-locked fiber laser using SU8 resist incorporating carbon nanotubes

    Science.gov (United States)

    Hernandez-Romano, Ivan; Mandridis, Dimitrios; May-Arrioja, Daniel A.; Sanchez-Mondragon, Jose J.; Delfyett, Peter J.

    2011-06-01

    We report the fabrication of a saturable absorber made of a novel polymer SU8 doped with Single Wall Carbon Nanotubes (SWCNTs). A passive mode-locked ring cavity fiber laser was built with a 100 μm thick SU8/SWCNT film inserted between two FC/APC connectors. Self-starting passively mode-locked lasing operation was observed at 1572.04 nm, with a FWHM of 3.26 nm. The autocorrelation trace was 1.536 ps corresponding to a pulse-width of 871 fs. The time-bandwidth product was 0.344, which is close enough to transform-limited sech squared pulses. The repetition rate was 21.27 MHz, and a maximum average output power of 1 mW was also measured.

  19. A Q-Switched Erbium-Doped Fiber Laser with a Carbon Nanotube Based Saturable Absorber

    International Nuclear Information System (INIS)

    Harun, S. W.; Ismail, M. A.; Ahmad, F.; Ismail, M. F.; Nor, R. M.; Zulkepely, N. R.; Ahmad, H.

    2012-01-01

    We demonstrate a simple, compact and low cost Q-switched erbium-doped fiber laser (EDFL) using single-wall carbon nanotubes (CNTs) as a saturable absorber for possible applications in metrology, sensing, and medical diagnostics. The EDFL operates at around 1560 nm with repetition rates of 16.1 kHz and 6.4 kHz with saturable absorbers SA1 and SA2 at a pump power of 120 mW. The absorbers are constructed by optically driven deposition and normal deposition techniques. It is observed that the optical deposition method produces a Q-switched EDFL with a lower threshold of 70 mW and better Q-switching performance compared to that of the normal deposition method. The EDFL also has pulse energy of 90.3 nJ and pulse width of 11.6 μs at 120 mW pump power

  20. Chemically bonded carbon nanotubes on modified gold substrate as novel unbreakable solid phase microextraction fiber

    International Nuclear Information System (INIS)

    Bagheri, H.; Ayazi, Z.; Sistani, H.

    2011-01-01

    A new technique is introduced for preparation of an unbreakable fiber using gold wire as a substrate for solid phase microextraction (SPME). A gold wire is used as a solid support, onto which a first film is deposited that consists of a two-dimensional polymer obtained by hydrolysis of a self-assembled monolayer of 3-(trimethoxysilyl)-1-propanthiol. This first film is covered with a layer of 3-(triethoxysilyl)-propylamine. Next, a stationary phase of oxidized multi-walled carbon nanotubes was chemically bound to the surface. The synthetic strategy was verified by Fourier transform infrared spectroscopy and scanning electron microscopy. Thermal stability of new fiber was examined by thermogravimetric analysis. The applicability of the novel coating was verified by its employment as a SPME fiber for isolation of diazinon and fenthion, as model compounds. Parameters influencing the extraction process were optimized to result in limits of detection as low as 0.2 ng mL -1 for diazinon, and 0.3 ng mL -1 for fenthion using the time-scheduled selected ion monitoring mode. The method was successfully applied to real water, and the recoveries for spiked samples were 104% for diazinon and 97% for fenthion. (author)

  1. Enhanced electro-Fenton Mineralization of Acid Orange 7 Using a Carbon Nanotube Fiber Based Cathode

    Science.gov (United States)

    Huong Le, Thi Xuan; Alemán, Belén; Vilatela, Juan J.; Bechelany, Mikhael; Cretin, Marc

    2018-02-01

    A new cathodic material for electro-Fenton (EF) process was prepared based on a macroscopic fiber (CNTF) made of mm long carbon nanotubes directly spun from the gas phase by floating catalyst CVD, on a carbon fiber (CF) substrate. CNTF@CF electrode is a highly graphitic material combining a high surface area ( 260 m2/g) with high electrical conductivity and electrochemical stability . One kind of azo dye, acid orange 7 (AO7), was used as model bio-refractory pollutant to be treated at CNTF@CF cathode in acidic aqueous medium (pH 3.0). The experimental results pointed out that AO7 and its organic intermediate compounds were totally mineralized by hydroxyl radical generated from Fenton reaction. In fact, 96.7 % of the initial TOC was eliminated in 8h of electrolysis by applying a current of -25 mA and ferrous ions as catalyst at concentration of 0.2 mM. At the same electrolysis time, only 23.7 % of TOC removal found on CF support which proved the high mineralization efficiency of new material thanks to CNTs deposition. The CNTF@CF cathode maintained stable its activity during five experimental cycles of EF set-up. The results indicated that CNTF@CF material could be a potential choice for wastewater treatment containing bio-refractory by electrochemical advanced oxidation processes (EAOPs).

  2. 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.

  3. High performance natural rubber composites with a hierarchical reinforcement structure of carbon nanotube modified natural fibers

    International Nuclear Information System (INIS)

    Tzounis, Lazaros; Debnath, Subhas; Rooj, Sandip; Fischer, Dieter; Mäder, Edith; Das, Amit; Stamm, Manfred; Heinrich, Gert

    2014-01-01

    A simple and facile method for depositing multiwall carbon nanotubes (MWCNTs) onto the surface of naturally occurring short jute fibers (JFs) is reported. Hierarchical multi-scale structures were formed with CNT-networks uniformly distributed and fully covering the JFs (JF–CNT), as depicted by the scanning electron microscopy (SEM) micrographs. The impact of these hybrid fillers on the mechanical properties of a natural rubber (NR) matrix was systematically investigated. Pristine JFs were cut initially to an average length of 2.0 mm and exposed to an alkali treatment (a-JFs) to remove impurities existing in the raw jute. MWCNTs were treated under mild acidic conditions to generate carboxylic acid moieties. Afterward, MWCNTs were dispersed in an aqueous media and short a-JFs were allowed to react with them. Raman spectroscopy confirmed the chemical interaction between CNTs and JFs. The JF–CNT exposed quite hydrophobic behavior as revealed by the water contact angle measurements, improving the wettability of the non-polar NR. Consequently, the composite interfacial adhesion strength was significantly enhanced while a micro-scale “mechanical interlocking” mechanism was observed from the interphase-section transmission electron microscopy (TEM) images. SEM analysis of the composite fracture surfaces demonstrated the interfacial strength of NR/a-JF and NR/JF–CNT composites, at different fiber loadings. It can be presumed that the CNT-coating effectively compatibillized the composite structure acting as a macromolecular coupling agent. A detailed analysis of stress-strain and dynamic mechanical spectra confirmed the high mechanical performance of the hierarchical composites, consisting mainly of materials arising from natural resources. - Highlights: • Natural rubber (NR) composites reinforced with CNT-modified short jute fibers. • MWCNTs deposited to the surface of jute fibers via non-covalent interactions. • Hierarchical reinforcement structure with

  4. Thermal oxidation induced degradation of carbon fiber reinforced composites and carbon nanotube sheet enhanced fiber/matrix interface for high temperature aerospace structural applications

    Science.gov (United States)

    Haque, Mohammad Hamidul

    epoxy resin has been characterized for hardness and modulus using nanoindentation technique. A significant reduction of oxidation, which is anticipated to eventually translate into improvement in mechanical properties, has been observed as the nanoclay particles have worked as a retarding agent for the oxidation propagation. Carbon nanotube sheet scrolled carbon fiber tows embedded in epoxy matrix have been investigated for interfacial properties using nanoindentation (push-out test), in micro scale, and using tensile testing (pull-out test), in macro scale. A significant increase in interfacial shear strength has been achieved by this unique materials combination.

  5. Direct growth of vanadium nitride nanosheets on carbon nanotube fibers as novel negative electrodes for high-energy-density wearable fiber-shaped asymmetric supercapacitors

    Science.gov (United States)

    Guo, Jiabin; Zhang, Qichong; Sun, Juan; Li, Chaowei; Zhao, Jingxin; Zhou, Zhenyu; He, Bing; Wang, Xiaona; Man, Ping; Li, Qiulong; Zhang, Jun; Xie, Liyan; Li, Mingxing; Yao, Yagang

    2018-04-01

    Significant efforts have been recently devoted to constructing high-performance fiber-shaped asymmetric supercapacitors. However, it is still a paramount challenge to develop high-energy-density fiber-shaped asymmetric supercapacitors for practical applications in portable and wearable electronics. This work reports a simple and efficient method to directly grow vanadium nitride nanosheets on carbon nanotube fibers as advanced negative electrodes with a high specific capacitance of 188 F/cm3 (564 mF/cm2). Taking advantage of their attractive structure, we successfully fabricated a fiber-shaped asymmetric supercapacitor device with a maximum operating voltage of 1.6 V by assembling the vanadium nitride/carbon nanotube fiber negative electrode with the Zinc-Nickel-Cobalt ternary oxides nanowire arrays positive electrode. Due to the excellent synergistic effects between positive and negative electrodes, a remarkable specific capacitance of 50 F/cm3 (150 mF/cm2) and an outstanding energy density of 17.78 mWh/cm3 (53.33 μWh/cm2) for our fiber-shaped asymmetric supercapacitor can be achieved. Furthermore, the as-assembled fiber-shaped asymmetric supercapacitor device has excellent mechanical flexibility in that 91% of the capacitance retained after bending 90° for 3000 times. Thus, this work exploits a pathway to construct high-energy-density fiber-shaped asymmetric supercapacitor for next-generation portable and wearable electronics.

  6. Vertically aligned carbon nanotube-sheathed carbon fibers as pristine microelectrodes for selective monitoring of ascorbate in vivo.

    Science.gov (United States)

    Xiang, Ling; Yu, Ping; Hao, Jie; Zhang, Meining; Zhu, Lin; Dai, Liming; Mao, Lanqun

    2014-04-15

    Using as-synthesized vertically aligned carbon nanotube-sheathed carbon fibers (VACNT-CFs) as microelectrodes without any postsynthesis functionalization, we have developed in this study a new method for in vivo monitoring of ascorbate with high selectivity and reproducibility. The VACNT-CFs are formed via pyrolysis of iron phthalocyanine (FePc) on the carbon fiber support. After electrochemical pretreatment in 1.0 M NaOH solution, the pristine VACNT-CF microelectrodes exhibit typical microelectrode behavior with fast electron transfer kinetics for electrochemical oxidation of ascorbate and are useful for selective ascorbate monitoring even with other electroactive species (e.g., dopamine, uric acid, and 5-hydroxytryptamine) coexisting in rat brain. Pristine VACNT-CFs are further demonstrated to be a reliable and stable microelectrode for in vivo recording of the dynamic increase of ascorbate evoked by intracerebral infusion of glutamate. Use of a pristine VACNT-CF microelectrode can effectively avoid any manual electrode modification and is free from person-to-person and/or electrode-to-electrode deviations intrinsically associated with conventional CF electrode fabrication, which often involves electrode surface modification with randomly distributed CNTs or other pretreatments, and hence allows easy fabrication of highly selective, reproducible, and stable microelectrodes even by nonelectrochemists. Thus, this study offers a new and reliable platform for in vivo monitoring of neurochemicals (e.g., ascorbate) to largely facilitate future studies on the neurochemical processes involved in various physiological events.

  7. Reinforced carbon fiber laminates with oriented carbon nanotube epoxy nanocomposites: Magnetic field assisted alignment and cryogenic temperature mechanical properties.

    Science.gov (United States)

    He, Yuxin; Yang, Song; Liu, Hu; Shao, Qian; Chen, Qiuyu; Lu, Chang; Jiang, Yuanli; Liu, Chuntai; Guo, Zhanhu

    2018-05-01

    The epoxy nanocomposites with ordered multi-walled carbon nanotubes (MWCNTs) were used to influence the micro-cracks resistance of carbon fiber reinforced epoxy (CF/EP) laminate at 77 K, Oxidized MWCNTs functionalized with Fe 3 O 4 (Fe 3 O 4 /O-MWCNTs) with good magnetic properties were prepared by co-precipitation method and used to modify epoxy (EP) for cryogenic applications. Fe 3 O 4 /O-MWCNTs reinforced carbon fiber epoxy composites were also prepared through vacuum-assisted resin transfer molding (VARTM). The ordered Fe 3 O 4 /O-MWCNTs were observed to have effectively improved the mechanical properties of epoxy (EP) matrix at 77 K and reduce the coefficient of thermal expansion (CTE) of EP matrix. The ordered Fe 3 O 4 /O-MWCNTs also obviously improved the micro-cracks resistance of CF/EP composites at 77 K. Compared to neat EP, the CTE of ordered Fe 3 O 4 /O-MWCNTs modified CF/EP composites was decreased 37.6%. Compared to CF/EP composites, the micro-cracks density of ordered Fe 3 O 4 /O-MWCNTs modified CF/EP composites at 77 K was decreased 37.2%. Copyright © 2018 Elsevier Inc. All rights reserved.

  8. The effects of carbon nanotube addition and oxyfluorination on the glucose-sensing capabilities of glucose oxidase-coated carbon fiber electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Im, Ji Sun; Yun, Jumi; Kim, Jong Gu [Department of Fine Chemical Engineering and Applied Chemistry, BK21-E2 M, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Bae, Tae-Sung [Department of Fine Chemical Engineering and Applied Chemistry, BK21-E2 M, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Korea Basic Science Institute (KBSI), Jeonju 561-756 (Korea, Republic of); Lee, Young-Seak, E-mail: youngslee@cnu.ac.kr [Department of Fine Chemical Engineering and Applied Chemistry, BK21-E2 M, Chungnam National University, Daejeon 305-764 (Korea, Republic of)

    2012-01-15

    Glucose-sensing electrodes were constructed from carbon fibers by electrospinning and heat treatment. By controlling the pore size, the specific surface area and pore volume of the electrospun carbon fibers were increased for efficient immobilization of the glucose oxidase. Carbon nanotubes were embedded as an electrically conductive additive to improve the electrical property of the porous carbon fibers. In addition, the surface of the porous carbon fibers was modified with hydrophilic functional groups by direct oxyfluorination to increase the affinity between the hydrophobic carbon surface and the hydrophilic glucose oxidase molecules. The porosity of the carbon fibers was improved significantly with approximately 28- and 35-fold increases in the specific surface area and pore volume, respectively. The number of chemical bonds between carbon and oxygen were increased with higher oxygen content during oxyfluorination based on the X-ray photoelectron spectroscopy results. Glucose sensing was carried out by current voltagram and amperometric methods. A high-performance glucose sensor was obtained with high sensitivity and rapid response time as a result of carbon nanotube addition, physical activation and surface modification. The mechanism of the highly sensitive prepared glucose sensor was modeled by an enzyme kinetics study using the Michaelis-Menten equation.

  9. Experimental Investigation of the Piezoresistive Properties of Cement Composites with Hybrid Carbon Fibers and Nanotubes

    Directory of Open Access Journals (Sweden)

    Seung-Jung Lee

    2017-11-01

    Full Text Available Cement-based sensors with hybrid conductive fillers using both carbon fibers (CFs and multi-walled carbon nanotubes (MWCNTs were experimentally investigated in this study. The self-sensing capacities of cement-based composites with only CFs or MWCNTs were found based on preliminary tests. The results showed that the percolation thresholds of CFs and MWCNTs were 0.5–1.0 vol.% and 1.0 vol.%, respectively. Based on these results, the feasibility of self-sensing composites with four different amounts of CFs and MWCNTs was considered under cyclic compression loads. When the amount of incorporated CFs increased and the amount of incorporated MWCNTs decreased, the self-sensing capacity of the composites was reduced. It was concluded that cement-based composites containing both 0.1 vol.% CFs and 0.5 vol.% MWCNTs could be an alternative to cement-based composites with 1.0 vol.% MWCNTs in order to achieve equivalent self-sensing performance at half the price. The gauge factor (GF for that composite was 160.3 with an R-square of 0.9274 in loading stages I and II, which was similar to the GF of 166.6 for the composite with 1.0 vol.% MWCNTs.

  10. Fabricating and strengthening the carbon nanotube/copper composite fibers with high strength and high electrical conductivity

    Science.gov (United States)

    Han, Baoshuai; Guo, Enyu; Xue, Xiang; Zhao, Zhiyong; Li, Tiejun; Xu, Yanjin; Luo, Liangshun; Hou, Hongliang

    2018-05-01

    Combining the excellent properties of carbon nanotube (CNT) and copper, CNT/Cu composite fibers were fabricated by physical vapor deposition (PVD) and rolling treatment. Dense and continuous copper film (∼2 μm) was coated on the surface of the CNT fibers by PVD, and rolling treatment was adopt to strengthen the CNT/Cu composite fibers. After the rolling treatment, the defects between the Cu grains and the CNT bundles were eliminated, and the structure of both the copper film and the core CNT fibers were optimized. The rolled CNT/Cu composite fibers possess high tensile effective strength (1.01 ± 0.13 GPa) and high electrical conductivity ((2.6 ± 0.3) × 107 S/m), and thus, this material may become a promising wire material.

  11. Carbon nanotube- and carbon fiber-reinforcement of ethylene-octene copolymer membranes for gas and vapor separation.

    Science.gov (United States)

    Sedláková, Zuzana; Clarizia, Gabriele; Bernardo, Paola; Jansen, Johannes Carolus; Slobodian, Petr; Svoboda, Petr; Kárászová, Magda; Friess, Karel; Izak, Pavel

    2014-01-03

    Gas and vapor transport properties were studied in mixed matrix membranes containing elastomeric ethylene-octene copolymer (EOC or poly(ethylene-co-octene)) with three types of carbon fillers: virgin or oxidized multi-walled carbon nanotubes (CNTs) and carbon fibers (CFs). Helium, hydrogen, nitrogen, oxygen, methane, and carbon dioxide were used for gas permeation rate measurements. Vapor transport properties were studied for the aliphatic hydrocarbon (hexane), aromatic compound (toluene), alcohol (ethanol), as well as water for the representative samples. The mechanical properties and homogeneity of samples was checked by stress-strain tests. The addition of virgin CNTs and CFs improve mechanical properties. Gas permeability of EOC lies between that of the more permeable PDMS and the less permeable semi-crystalline polyethylene and polypropylene. Organic vapors are more permeable than permanent gases in the composite membranes, with toluene and hexane permeabilities being about two orders of magnitude higher than permanent gas permeability. The results of the carbon-filled membranes offer perspectives for application in gas/vapor separation with improved mechanical resistance.

  12. Carbon Nanotube- and Carbon Fiber-Reinforcement of Ethylene-Octene Copolymer Membranes for Gas and Vapor Separation

    Directory of Open Access Journals (Sweden)

    Zuzana Sedláková

    2014-01-01

    Full Text Available Gas and vapor transport properties were studied in mixed matrix membranes containing elastomeric ethylene-octene copolymer (EOC or poly(ethylene-co-octene with three types of carbon fillers: virgin or oxidized multi-walled carbon nanotubes (CNTs and carbon fibers (CFs. Helium, hydrogen, nitrogen, oxygen, methane, and carbon dioxide were used for gas permeation rate measurements. Vapor transport properties were studied for the aliphatic hydrocarbon (hexane, aromatic compound (toluene, alcohol (ethanol, as well as water for the representative samples. The mechanical properties and homogeneity of samples was checked by stress-strain tests. The addition of virgin CNTs and CFs improve mechanical properties. Gas permeability of EOC lies between that of the more permeable PDMS and the less permeable semi-crystalline polyethylene and polypropylene. Organic vapors are more permeable than permanent gases in the composite membranes, with toluene and hexane permeabilities being about two orders of magnitude higher than permanent gas permeability. The results of the carbon-filled membranes offer perspectives for application in gas/vapor separation with improved mechanical resistance.

  13. Grafting Carbon Nanotubes on Glass Fiber by Dip Coating Technique to Enhance Tensile and Interfacial Shear Strength

    Directory of Open Access Journals (Sweden)

    Bahador Dastorian Jamnani

    2015-01-01

    Full Text Available The effects of noncovalent bonding and mechanical interlocking of carbon nanotubes (CNT coating on tensile and interfacial strength of glass fiber were investigated. CNT were coated over glass fiber by a simple dip coating method. Acid treated CNT were suspended in isopropanol solution containing Nafion as binding agent. To achieve uniform distribution of CNT over the glass fiber, an optimized dispersion process was developed by two parameters: CNT concentration and soaking time. CNT concentration was varied from 0.4 to 2 mg/mL and soaking time was varied from 1 to 180 min. The provided micrographs demonstrated appropriate coating of CNT on glass fiber by use of CNT-Nafion mixture. The effects of CNT concentration and soaking time on coating layer were studied by performing single fiber tensile test and pull-out test. The obtained results showed that the optimum CNT concentration and soaking time were 1 mg/mL and 60 min, respectively, which led to significant improvement of tensile strength and interfacial shear stress. It was found that, at other concentrations and soaking times, CNT agglomeration or acutely curly tubes appeared over the fiber surface which caused a reduction of nanotubes interaction on the glass fiber.

  14. Surface decoration of polyimide fiber with carbon nanotubes and its application for mechanical enhancement of phosphoric acid-based geopolymers

    Science.gov (United States)

    Yang, Tao; Han, Enlin; Wang, Xiaodong; Wu, Dezhen

    2017-09-01

    A new methodology to decorate the surface of polyimide (PI) fiber with carbon nanotubes (CNTs) has been developed in this study. This surface decoration was carried out through a surface alkali treatment, a carboxylation modification, surface functionalization with acyl chloride groups and then with amino groups, and a surface graft of CNTs onto PI fiber. Fourier-transform infrared and X-ray photoelectron spectroscopic characterizations confirmed that CNTs were chemically grafted onto the surface of PI fiber, and scanning electron microscopic observation demonstrated the fiber surface was uniformly and densely covered with CNTs. The surface energy and wettability of PI fiber were improved in the presence of CNTs on the fiber surface, which made a contribution to enhance the interfacial adhesion of PI fiber with other inorganic matrices when used as a reinforcing fiber. The application of CNTs-decorated PI fiber for the reinforcement of phosphoric acid-based geopolymers was investigated, and the results indicated that the geopolymeric composites gained a noticeable reinforcement. Compared to unreinforced geopolymer, the geopolymeric composites achieved a remarkable increase in compressive strength by 120% and in flexural strength by 283%. Fractography investigation demonstrated that the interaction adhesion between the fibers and matrix was enhanced due to the surface decoration of PI fiber with CNTs, which contributed to an improvement in fracture-energy dissipation by fiber pullout and fiber debonding from the matrix. As a result, a significant reinforcement effect on geopolymeric composites was achieved through a fiber-bridging mechanism. This study provided an effective methodology to improve the interracial bonding force for PI fiber and also proves a highly efficient application of CNTs-decorated PI fiber for the mechanical enhancement of geopolymeric composites.

  15. Carbon Nanotube Fiber Ionization Mass Spectrometry: A Fundamental Study of a Multi-Walled Carbon Nanotube Functionalized Corona Discharge Pin for Polycyclic Aromatic Hydrocarbons Analysis

    Science.gov (United States)

    Nahan, Keaton S.; Alvarez, Noe; Shanov, Vesselin; Vonderheide, Anne

    2017-09-01

    Mass spectrometry continues to tackle many complicated tasks, and ongoing research seeks to simplify its instrumentation as well as sampling. The desorption electrospray ionization (DESI) source was the first ambient ionization source to function without extensive gas requirements and chromatography. Electrospray techniques generally have low efficiency for ionization of nonpolar analytes and some researchers have resorted to methods such as direct analysis in real time (DART) or desorption atmospheric pressure chemical ionization (DAPCI) for their analysis. In this work, a carbon nanotube fiber ionization (nanoCFI) source was developed and was found to be capable of solid phase microextraction (SPME) of nonpolar analytes as well as ionization and sampling similar to that of direct probe atmospheric pressure chemical ionization (DP-APCI). Conductivity and adsorption were maintained by utilizing a corona pin functionalized with a multi-walled carbon nanotube (MWCNT) thread. Quantitative work with the nanoCFI source with a designed corona discharge pin insert demonstrated linearity up to 0.97 (R2) of three target PAHs with phenanthrene internal standard. [Figure not available: see fulltext.

  16. Flexible and stretchable lithium-ion batteries and supercapacitors based on electrically conducting carbon nanotube fiber springs.

    Science.gov (United States)

    Zhang, Ye; Bai, Wenyu; Cheng, Xunliang; Ren, Jing; Weng, Wei; Chen, Peining; Fang, Xin; Zhang, Zhitao; Peng, Huisheng

    2014-12-22

    The construction of lightweight, flexible and stretchable power systems for modern electronic devices without using elastic polymer substrates is critical but remains challenging. We have developed a new and general strategy to produce both freestanding, stretchable, and flexible supercapacitors and lithium-ion batteries with remarkable electrochemical properties by designing novel carbon nanotube fiber springs as electrodes. These springlike electrodes can be stretched by over 300 %. In addition, the supercapacitors and lithium-ion batteries have a flexible fiber shape that enables promising applications in electronic textiles. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Dynamics of a Dispersion-Managed Passively Mode-Locked Er-Doped Fiber Laser Using Single Wall Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Norihiko Nishizawa

    2015-07-01

    Full Text Available We investigated the dynamics of a dispersion-managed, passively mode-locked, ultrashort-pulse, Er-doped fiber laser using a single-wall carbon nanotube (SWNT device. A numerical model was constructed for analysis of the SWNT fiber laser. The initial process of passive mode-locking, the characteristics of the output pulse, and the dynamics inside the cavity were investigated numerically for soliton, dissipative-soliton, and stretched-pulse mode-locking conditions. The dependencies on the total dispersion and recovery time of the SWNTs were also examined. Numerical results showed similar behavior to experimental results.

  18. Chitosan surface modified electrospun poly(ε-caprolactone)/carbon nanotube composite fibers with enhanced mechanical, cell proliferation and antibacterial properties.

    Science.gov (United States)

    Wang, Siyu; Li, Yumei; Zhao, Rui; Jin, Toufeng; Zhang, Li; Li, Xiang

    2017-11-01

    The surface modification is one of the most effective methods to improve the bioactivity and cell affinity effect of electrospun poly(ε-caprolactone) (PCL) fibers. In the present study, chitosan (CS), a cationic polysaccharide, was used to modify the surface of electrospun PCL fibers. To obtain strong interaction between CS and PCL fibers, negatively charged PCL fibers were prepared by the incorporation of acid-treated carbon nanotubes (CNTs) into the fibers. In this way, the positively charged chitosan could be immobilized onto the surface of PCL fibers tightly by the electrostatic attraction. Besides, the incorporation of CNTs could significantly improve the mechanical strength of electrospun PCL fibers even after the CS modification, which guaranteed their usability in practical applications. The CS modification could effectively improve the wettability and bioactivity of electrospun PCL fibers. Cultivation of L929 fibroblast cells on the obtained fibers and the antibacterial activity were both evaluated to discuss the influence of chitosan modification. The results indicated that this modification could enhance the cell proliferation and antibacterial ability in comparison to the non-modified groups. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. 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.

  20. Self-Sensing of Single Carbon Fiber/Carbon Nanotube-Epoxy Composites Using Electro-Micromechanical Techniques and Acoustic Emission

    International Nuclear Information System (INIS)

    Park, Joung Man; Jang, Jung Hoon; Wang, Zuo Jia; Kwon, Dong Jun; Park, Jong Kyu; Lee, Woo Il

    2010-01-01

    Self-sensing on micro-failure, dispersion degree and relating properties, of carbon nanotube(CNT)/epoxy composites, were investigated using wettability, electro-micromechanical technique with acoustic emission(AE). Specimens were prepared from neat epoxy as well as composites with untreated and acid-treated CNT. Degree of dispersion was evaluated comparatively by measuring volumetric electrical resistivity and its standard deviation. Apparent modulus containing the stress transfer was higher for acid-treated CNT composite than for the untreated case. Applied cyclic loading responded well for a single carbon fiber/CNT-epoxy composite by the change in contact resistivity. The interfacial shear strength between a single carbon fiber and CNT-epoxy, determined in a fiber pullout test, was lower than that between a single carbon fiber and neat epoxy. Regarding on micro-damage sensing using electrical resistivity measurement with AE, the stepwise increment in electrical resistivity was observed for a single carbon fiber/CNT-epoxy composite. On the other hand, electrical resistivity increased infinitely right after the first carbon fiber breaks for a single carbon fiber/neat epoxy composite. The occurrence of AE events of added CNT composites was much higher than the neat epoxy case, due to microfailure at the interfaces by added CNTs

  1. Strain monitoring of cement-based materials with embedded polyvinyl alcohol - carbon nanotube (PVA-CNT fibers

    Directory of Open Access Journals (Sweden)

    Zoi S. Metaxa

    2017-04-01

    Full Text Available This article investigates the possibility of exploiting innovative polyvinyl alcohol fibers reinforced with carbon nanotubes (PVA-CNT fiber as a strain sensor in cement mortars used in the restoration of Cultural Heritage Monuments. Two types of PVA-CNT fibers were embedded in the matrix at a short distance from the bottom of the beam and their readings were correlated with traditional sensors, e.g. strain gauges and Fiber Optic Bragg Gratings. The Electrical Resistance Change (ERC of the embedded PVA-CNT fiber was in-situ monitored during four-point bending mechanical tests. For the case of coated PVA-CNT fiber, a linear correlation of the applied strain at the bottom surface of the specimen along with ERC values of the fiber was noticed for the low strain regime. For the case of incremental increasing loading – unloading loops, the coated and annealed PVA-CNT fiber gave the best results either as embedded or as ‘surface attached’ sensor that exhibited linear correlation of ERC with applied strain for the low applied strain regime as well as hysteresis loops during unloading. The article discusses their high potential to be exploited as strain/damage sensor in applications of civil engineering as well as in restoration of Monuments of Cultural Heritage.

  2. Flame Retardancy Effects of Graphene Nanoplatelet/Carbon Nanotube Hybrid Membranes on Carbon Fiber Reinforced Epoxy Composites

    Directory of Open Access Journals (Sweden)

    Dongxian Zhuo

    2013-01-01

    Full Text Available Carbon nanotube/graphene nanoplatelet (MWCNT/GNP hybrid membranes with lower liquid permeability and better barrier effect compared to MWCNT membranes were successfully synthesized by vacuum filtering. Their morphologies, water permeability, and pore structures were characterized by a scanning electron microscope (SEM and nitrogen adsorption isotherms. Furthermore, MWCNT/GNP membranes were used to improve the flame retardancy of carbon fiber reinforced polymer (CFRP composites, and the influence of weight percentage of GNPs on the permeability and flame retardancy of MWCNT/GNP membranes was systematically investigated. Results show that incorporation of MWCNT/GNP membranes on CFRP composite plates can remarkably improve the flame retardancy of CFRP composites. Specifically, the incorporation of hierarchical MWCNT/GNP membrane with 7.5 wt% of GNP displays a 35% reduction in the peak heat release rate (PHRR for a CFRP composite plate with the epoxy as matrix and a 11% reduction in PHRR compared with the incorporation of MWCNT membrane only. A synergistic flame retarding mechanism is suggested to be attributed to these results, which includes controlling the pore size and penetrative network structure.

  3. Vertically aligned carbon nanotubes/carbon fiber paper composite to support Pt nanoparticles for direct methanol fuel cell application

    Science.gov (United States)

    Zhang, Jing; Yi, Xi-bin; Liu, Shuo; Fan, Hui-Li; Ju, Wei; Wang, Qi-Chun; Ma, Jie

    2017-03-01

    Vertically aligned carbon nanotubes (VACNTs) grown on carbon fiber paper (CFP) by plasma enhanced chemical vapor deposition is introduced as a catalyst support material for direct methanol fuel cells (DMFCs). Well dispersed Pt nanoparticles on VACNTs surface are prepared by impregnation-reduction method. The VACNTs on CFP possess well-maintained alignment, large surface area and good electrical conductivity, which leading to the formation of Pt particles with a smaller size and enhance the Pt utilization rate. The structure and nature of resulting Pt/VACNTs/CFP catalysts for methanol oxidation are investigated by transmission electron microscopy (TEM), X-ray diffraction (XRD) and scanning electron microscope (SEM). With the aid of VACNTs, well-dispersed Pt catalysts enable the reversibly rapid redox kinetic since electron transport efficiently passes through a one-dimensional pathway, which leads to enhance the catalytic activity and Pt utilization rate. Compared with the Pt/XC-72/CFP electrode, the electrochemical measurements results display that the Pt/VACNTs/CFP catalyst shows much higher electrocatalytic activity and better stability for methanol oxidation. In addition, the oxidation current from 200 to 1200 s decayed more slowly for the Pt/VACNTs/CFP than that of the Pt/XC-72/CFP catalysts, indicating less accumulation of adsorbed CO species. All those results imply that the Pt/VACNTs/CFP has a great potential for applications in DMFCs.

  4. Electrical and Self-Sensing Properties of Ultra-High-Performance Fiber-Reinforced Concrete with Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Ilhwan You

    2017-10-01

    Full Text Available This study examined the electrical and self-sensing capacities of ultra-high-performance fiber-reinforced concrete (UHPFRC with and without carbon nanotubes (CNTs. For this, the effects of steel fiber content, orientation, and pore water content on the electrical and piezoresistive properties of UHPFRC without CNTs were first evaluated. Then, the effect of CNT content on the self-sensing capacities of UHPFRC under compression and flexure was investigated. Test results indicated that higher steel fiber content, better fiber orientation, and higher amount of pore water led to higher electrical conductivity of UHPFRC. The effects of fiber orientation and drying condition on the electrical conductivity became minor as sufficiently high amount of steel fibers, 3% by volume, was added. Including only steel fibers did not impart UHPFRC with piezoresistive properties. Addition of CNTs substantially improved the electrical conductivity of UHPFRC. Under compression, UHPFRC with a CNT content of 0.3% or greater had a self-sensing ability that was activated by the formation of cracks, and better sensing capacity was achieved by including greater amount of CNTs. Furthermore, the pre-peak flexural behavior of UHPFRC was precisely simulated with a fractional change in resistivity when 0.3% CNTs were incorporated. The pre-cracking self-sensing capacity of UHPFRC with CNTs was more effective under tensile stress state than under compressive stress state.

  5. Electrical and Self-Sensing Properties of Ultra-High-Performance Fiber-Reinforced Concrete with Carbon Nanotubes.

    Science.gov (United States)

    You, Ilhwan; Yoo, Doo-Yeol; Kim, Sooho; Kim, Min-Jae; Zi, Goangseup

    2017-10-29

    This study examined the electrical and self-sensing capacities of ultra-high-performance fiber-reinforced concrete (UHPFRC) with and without carbon nanotubes (CNTs). For this, the effects of steel fiber content, orientation, and pore water content on the electrical and piezoresistive properties of UHPFRC without CNTs were first evaluated. Then, the effect of CNT content on the self-sensing capacities of UHPFRC under compression and flexure was investigated. Test results indicated that higher steel fiber content, better fiber orientation, and higher amount of pore water led to higher electrical conductivity of UHPFRC. The effects of fiber orientation and drying condition on the electrical conductivity became minor as sufficiently high amount of steel fibers, 3% by volume, was added. Including only steel fibers did not impart UHPFRC with piezoresistive properties. Addition of CNTs substantially improved the electrical conductivity of UHPFRC. Under compression, UHPFRC with a CNT content of 0.3% or greater had a self-sensing ability that was activated by the formation of cracks, and better sensing capacity was achieved by including greater amount of CNTs. Furthermore, the pre-peak flexural behavior of UHPFRC was precisely simulated with a fractional change in resistivity when 0.3% CNTs were incorporated. The pre-cracking self-sensing capacity of UHPFRC with CNTs was more effective under tensile stress state than under compressive stress state.

  6. Effect of Multiwalled Carbon Nanotubes on the Mechanical Properties of Carbon Fiber-Reinforced Polyamide-6/Polypropylene Composites for Lightweight Automotive Parts

    Directory of Open Access Journals (Sweden)

    Huu-Duc Nguyen-Tran

    2018-03-01

    Full Text Available The development of lightweight automotive parts is an important issue for improving the efficiency of vehicles. Polymer composites have been widely applied to reduce weight and improve mechanical properties by mixing polymers with carbon fibers, glass fibers, and carbon nanotubes. Polypropylene (PP has been added to carbon fiber-reinforced nylon-6 (CF/PA6 composite to achieve further weight reduction and water resistance. However, the mechanical properties were reduced by the addition of PP. In this research, multiwalled carbon nanotubes (CNTs were added to compensate for the reduced mechanical properties experienced when adding PP. Tensile testing and bending tests were carried out to evaluate the mechanical properties. A small amount of CNTs improved the mechanical properties of carbon fiber-reinforced PA6/PP composites. For example, the density of CF/PA6 was reduced from 1.214 to 1.131 g/cm3 (6.8% by adding 30 wt % PP, and the tensile strength of 30 wt % PP composite was improved from 168 to 173 MPa (3.0% by adding 0.5 wt % CNTs with small increase of density (1.135 g/cm3. The developed composite will be widely used for lightweight automotive parts with improved mechanical properties.

  7. Interlaminar improvement of carbon fiber/epoxy composites via depositing mixture of carbon nanotubes and sizing agent

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Cuiqin [Beijing Key Laboratory of Electrochemical Process and Technology for Materials, Beijing University of Chemical Technology, Beijing 100029 (China); Wang, Julin, E-mail: julinwang@126.com [Beijing Key Laboratory of Electrochemical Process and Technology for Materials, Beijing University of Chemical Technology, Beijing 100029 (China); Zhang, Tao [Beijing Institute of Ancient Architecture, Beijing 100050 (China)

    2014-12-01

    Graphical abstract: - Highlights: • COOH-CNTs can react with sizing agent, and the optimum reaction ratio was 1:20. • Carbon fibers were dipped into the mixture bath of CNTs and sizing agent. • SEM results indicate that fibers surfaces were coated with CNTs and sizing agent. • ILSS was increased by 67.01% for the composites after the mixture coating process. • Single fibers tensile strength was maintained after the deposited process. - Abstract: The effects of deposition to carbon fibers surfaces with mixture of functionalized multi-walled carbon fibers (MWCNTs) and sizing agent were investigated. Relationships between CNTs and sizing agent were studied with Fourier transform infrared spectrometer (FTIR), X-ray photoelectron spectroscopy (XPS) and Ubbelohde viscometer. The results revealed that CNTs could react with sizing agent at 120 °C, and optimal reaction occurs when mass ratio was about 1:20. Then, carbon fibers were immersed in mixed aqueous suspension of CNTs and sizing agent with the above ratio dispersed by ultrasonication. According to scanning electron microscope (SEM) observations, fibers surfaces were coated with CNTs and sizing agent. The static contact angle tests indicated wetting performance between fibers and epoxy resin were improved after deposited procedures. Interlaminar shear strength was increased by 67.01% for fibers/epoxy resin composites after mixture deposited process. Moreover, the tensile strength of single fibers after depositing showed a slightly increase compared with that of fibers without depositing layer.

  8. A novel extraction technique based on carbon nanotubes reinforced hollow fiber solid/liquid microextraction for the measurement of piroxicam and diclofenac combined with high performance liquid chromatography.

    Science.gov (United States)

    Song, Xin-Yue; Shi, Yan-Ping; Chen, Juan

    2012-10-15

    A novel design of carbon nanotubes reinforced hollow fiber solid/liquid phase microextraction (CNTs-HF-SLPME) was developed to determine piroxicam and diclofenac in different real water samples. Functionalized multi-walled carbon nanotubes (MWCNTs) were held in the pores of hollow fiber with sol-gel technology. The pores and lumen of carbon nanotubes reinforced hollow fiber were subsequently filled with a μL volume of organic solvent (1-octanol), and then the whole assembly was used for the extraction of the target analytes in direct immersion sampling mode. The target analytes were extracted from the sample by two extractants, one of which is organic solvent placed inside the pores and lumen of hollow fiber and the other one is CNTs held in the pores of hollow fiber. After extraction, the analytes were desorbed in acetonitrile and analyzed using high performance liquid chromatography. This novel extraction mode showed more excellent extraction performance in comparison with conventional hollow fiber liquid microextraction (without adding CNTs) and carbon nanotubes reinforced hollow fiber solid microextraction (CNTs held in the pores of hollow fiber, but no organic solvents placed inside the lumen of hollow fiber) under the respective optimum conditions. This method provided 47- and 184-fold enrichment factors for piroxicam and diclofenac, respectively, good inter-fiber repeatability and batch-to-batch reproducibility. Linearity was observed in the range of 20-960 μg L(-1) for piroxicam, and 10-2560 μg L(-1) for diclofenac, with correlation coefficients of 0.9985 and 0.9989, respectively. The limits of detection were 4.58 μg L(-1) for piroxicam and 0.40 μg L(-1) for diclofenac. Copyright © 2012 Elsevier B.V. All rights reserved.

  9. Functional materials based on carbon nanotubes: Carbon nanotube actuators and noncovalent carbon nanotube modification

    Science.gov (United States)

    Fifield, Leonard S.

    Carbon nanotubes have attractive inherent properties that encourage the development of new functional materials and devices based on them. The use of single wall carbon nanotubes as electromechanical actuators takes advantage of the high mechanical strength, surface area and electrical conductivity intrinsic to these molecules. The work presented here investigates the mechanisms that have been discovered for actuation of carbon nanotube paper: electrostatic, quantum chemical charge injection, pneumatic and viscoelastic. A home-built apparatus for the measurement of actuation strain is developed and utilized in the investigation. An optical fiber switch, the first demonstrated macro-scale device based on the actuation of carbon nanotubes, is described and its performance evaluated. Also presented here is a new general process designed to modify the surface of carbon nanotubes in a non-covalent, non-destructive way. This method can be used to impart new functionalities to carbon nanotube samples for a variety of applications including sensing, solar energy conversion and chemical separation. The process described involves the achievement of large degrees of graphitic surface coverage with polycyclic aromatic hydrocarbons through the use of supercritical fluids. These molecules are bifunctional agents that anchor a desired chemical group to the aromatic surface of the carbon nanotubes without adversely disrupting the conjugated backbone that gives rise the attractive electronic and physical properties of the nanotubes. Both the nanotube functionalization work and the actuator work presented here emphasize how an understanding and control of nanoscale structure and phenomena can be of vital importance in achieving desired performance for active materials. Opportunities for new devices with improved function over current state-of-the-art can be envisioned and anticipated based on this understanding and control.

  10. Wear of carbon nanotubes grafted on carbon fibers and this influence on the properties of composites materials

    Science.gov (United States)

    Guignier, Claire; Bueno, Marie-Ange; Camillieri, Brigitte; Durand, Bernard

    2017-10-01

    Carbon nanotubes (CNTs) grafted on carbon surfaces can be used to reinforce composite materials. During an industrial process of CNTs production and composite processing, friction stresses will be applied on CNTs. This study showed that CNTs formed a transfer film under friction stresses and that the wear of the CNTs has no influence on the wettability of the surface, so we can predict no decrease in the properties of composites.

  11. Transformation of the released asbestos, carbon fibers and carbon nanotubes from composite materials and the changes of their potential health impacts.

    Science.gov (United States)

    Wang, Jing; Schlagenhauf, Lukas; Setyan, Ari

    2017-02-20

    Composite materials with fibrous reinforcement often provide superior mechanical, thermal, electrical and optical properties than the matrix. Asbestos, carbon fibers and carbon nanotubes (CNTs) have been widely used in composites with profound impacts not only on technology and economy but also on human health and environment. A large number of studies have been dedicated to the release of fibrous particles from composites. Here we focus on the transformation of the fibrous fillers after their release, especially the change of the properties essential for the health impacts. Asbestos fibers exist in a large number of products and the end-of-the-life treatment of asbestos-containing materials poses potential risks. Thermal treatment can transform asbestos to non-hazardous phase which provides opportunities of safe disposal of asbestos-containing materials by incineration, but challenges still exist. Carbon fibers with diameters in the range of 5-10 μm are not considered to be respirable, however, during the release process from composites, the carbon fibers may be split along the fiber axis, generating smaller and respirable fibers. CNTs may be exposed on the surface of the composites or released as free standing fibers, which have lengths shorter than the original ones. CNTs have high thermal stability and may be exposed after thermal treatment of the composites and still keep their structural integrity. Due to the transformation of the fibrous fillers during the release process, their toxicity may be significantly different from the virgin fibers, which should be taken into account in the risk assessment of fiber-containing composites.

  12. Dynamic mechanical analysis and high strain-rate energy absorption characteristics of vertically aligned carbon nanotube reinforced woven fiber-glass composites

    Science.gov (United States)

    The dynamic mechanical behavior and energy absorption characteristics of nano-enhanced functionally graded composites, consisting of 3 layers of vertically aligned carbon nanotube (VACNT) forests grown on woven fiber-glass (FG) layer and embedded within 10 layers of woven FG, with polyester (PE) and...

  13. Gel spinning of PVA composite fibers with high content of multi-walled carbon nanotubes and graphene oxide hybrids

    International Nuclear Information System (INIS)

    Wei, Yizhe; Lai, Dengpan; Zou, Liming; Ling, Xinlong; Lu, Hongwei; Xu, Yongjing

    2015-01-01

    In this report, poly (vinyl alcohol) (PVA) composite fibers with high content of multi-walled carbon nanotubes and graphene oxide (MWCNTs-GO) hybrids were prepared by gel spinning, and were characterized by TGA, DSC, SEM, XL-2 yarn strength tester and electrical conductivity measurement. The total content of MWCNTs-GO hybrids in the PVA composite fibers, which is up to 25 wt%, was confirmed by TGA analysis. The DSC measurement shows that the melting and crystallization peaks decreased after the addition of nano-fillers. This is due to the reason that the motion of PVA chains is completely confined by strong hydrogen bonding interaction between PVA and nano-fillers. After the addtion of GO, the dispersibility of MWCNTs in composite fibers improved slightly. And the tensile strength and Young's modulus increased by 38% and 67%, respectively. This is caused by the increased hydrogen bonding interaction and synergistic effect through hybridization of MWCNTs and GO. More significantly, the electrical conductivity of PVA/MWCNTs/GO composite fibers enhanced by three orders of magnitude with the addition of GO. (paper)

  14. Flexible nanohybrid microelectrode based on carbon fiber wrapped by gold nanoparticles decorated nitrogen doped carbon nanotube arrays: In situ electrochemical detection in live cancer cells.

    Science.gov (United States)

    Zhang, Yan; Xiao, Jian; Sun, Yimin; Wang, Lu; Dong, Xulin; Ren, Jinghua; He, Wenshan; Xiao, Fei

    2018-02-15

    The rapidly growing demand for in situ real-time monitoring of chemical information in vitro and in vivo has attracted tremendous research efforts into the design and construction of high-performance biosensor devices. Herein, we develop a new type of flexible nanohybrid microelectrode based on carbon fiber wrapped by gold nanoparticles decorated nitrogen-doped carbon nanotube arrays, and explore its practical application in in situ electrochemical detection of cancer biomarker H 2 O 2 secreted from live cancer cells. Our results demonstrate that carbon fiber material with microscale size and fascinating mechanical properties can be used as a robust and flexible microelectrode substrate in the electrochemical biosensor system. And the highly ordered nitrogen-doped carbon nanotube arrays that grown on carbon fiber possess high surface area-to-volume ratio and abundant active sites, which facilitate the loading of high-density and uniformly dispersed gold nanoparticles on it. Benefited from the unique microstructure and excellent electrocatalytic properties of different components in the nanohybrid fiber microelectrode, an effective electrochemical sensing platform based on it has been built up for the sensitive and selective detection of H 2 O 2 , the detection limit is calculated to be 50nM when the signal-to-noise ratio is 3:1, and the linear dynamic range is up to 4.3mM, with a high sensitivity of 142µAcm -2 mM -1 . These good sensing performances, coupled with its intrinsic mechanical flexibility and biocompatibility, allow for its use in in situ real-time tracking H 2 O 2 secreted from breast cancer cell lines MCF-7 and MBA-MD-231, and evaluating the sensitivity of different cancer cells to chemotherapy or radiotherapy treatments, which hold great promise for clinic application in cancer diagnose and management. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. 1/f noise in carbon nanotubes

    International Nuclear Information System (INIS)

    Collins, Philip G.; Fuhrer, M. S.; Zettl, A.

    2000-01-01

    The electrical noise characteristics of single-walled carbon nanotubes have been investigated. For all three cases of individual isolated nanotubes, thin films of interconnected nanotubes, and bulk nanotube mats, anomalously large bias-dependent 1/f noise is found. The noise magnitude greatly exceeds that commonly observed in metal films, carbon resistors, or even carbon fibers with comparable resistances. A single empirical expression describes the noise for all nanotube samples, suggesting a common noise-generating mechanism proportional only to the number of nanotubes in the conductor. We consider likely sources of the fluctuations, and consequences for electronic applications of nanotubes if the excessive noise cannot be suppressed. (c) 2000 American Institute of Physics

  16. Enhanced Electro-Fenton Mineralization of Acid Orange 7 Using a Carbon Nanotube Fiber-Based Cathode

    Directory of Open Access Journals (Sweden)

    Thi Xuan Huong Le

    2018-02-01

    Full Text Available A new cathodic material for electro-Fenton (EF process was prepared based on a macroscopic fiber (CNTF made of mm-long carbon nanotubes directly spun from the gas phase by floating catalyst CVD, on a carbon fiber (CF substrate. CNTF@CF electrode is a highly graphitic material combining a high surface area (~260 m2/g with high electrical conductivity and electrochemical stability. One kind of azo dye, acid orange 7 (AO7, was used as model bio-refractory pollutant to be treated at CNTF@CF cathode in acidic aqueous medium (pH 3.0. The experimental results pointed out that AO7 and its organic intermediate compounds were totally mineralized by hydroxyl radical generated from Fenton reaction. In fact, 96.7% of the initial total organic carbon (TOC was eliminated in 8 h of electrolysis by applying a current of −25 mA and ferrous ions as catalyst at concentration of 0.2 mM. At the same electrolysis time, only 23.7% of TOC removal found on CF support which proved the high mineralization efficiency of new material thanks to CNTF deposition. The CNTF@CF cathode maintained stable its activity during five experimental cycles of EF setup. The results indicated that CNTF@CF material could be a potential choice for wastewater treatment containing bio-refractory by electrochemical advanced oxidation processes.

  17. Macroscopic Crosslinked Neat Carbon Nanotube Materials and CNT/Carbon Fiber Hybrid Composites: Supermolecular Structure and New Failure Mode Study

    Science.gov (United States)

    2015-10-01

    larger).48 Kim et al. studied the dispersion and alignment of CNTs in a gelatin film and the resulting DISTRIBUTION A: Distribution approved for...with the specimen dimension of 5×1 cm2. The two ends of the sample were polished and electrodes were connected using silver paste for better...Highly Polarized Absorption and Photoluminescence of Stretch-Aligned Single-Wall Carbon Nanotubes Dispersed in Gelatin Films. Appl. Phys. Lett. 2005, 86

  18. Recent development of carbon nanotube

    Energy Technology Data Exchange (ETDEWEB)

    Yamabe, Tokio [Div. of Molecular Engineering, Kyoto Univ. (Japan); [Inst. for Fundamental Chemistry, Kyoto (Japan)

    1995-03-15

    Recent developments of carbon nanotubes are reviewed. Analytical solutions for the electronic structure of carbon nanotube on the basis of thight-binding approximation are presented and interpreted using the concepts of crystal orbital. The electronic properties of actual carbon nanotubes are presented. The electronic structures of carbon nanotubes in the presence of magnetic fiels are also summerized. (orig.)

  19. Purification of carbon nanotubes via selective heating

    Science.gov (United States)

    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.

  20. Application of β-cyclodextrin-modified, carbon nanotube-reinforced hollow fiber to solid-phase microextraction of plant hormones.

    Science.gov (United States)

    Song, Xin-Yue; Ha, Wei; Chen, Juan; Shi, Yan-Ping

    2014-12-29

    A new, efficient, and environmental friendly solid-phase microextraction (SPME) medium based on β-cyclodextrin (β-CD)-modified carbon nanotubes (CNTs) and a hollow fiber (HF) was prepared. Functionalized β-CD was covalently linked to the surface of the carboxylic CNTs and then the obtained nanocomposite was immobilized into the wall pores of HFs under ultrasonic-assisted effect. The scanning electron microscope was used to inspect surface characteristics of fibers, demonstrating the presence of nanocomposites in their wall pores. The reinforced HF was employed in SPME, and its extraction performance was evaluated by analyzing 1-naphthaleneacetic acid (NAA) and 2-naphthoxyacetic acid (2-NOA) in vegetables. Without any tedious clean-up procedure, analytes were extracted from the sample to the adsorbent and organic solvent immobilized in HFs and then desorbed in acetonitrile prior to chromatographic analysis. Under the optimized extraction conditions, the method provided 275- and 283-fold enrichment factors of NAA and 2-NOA, low limits of detection and quantification (at an ngg(-1) level), satisfactory spiked recoveries, good inter-fiber repeatability, and batch-to-batch reproducibility. The selectivity of the developed fiber was investigated to three structurally similar compounds and two reference compounds with recognition coefficients up to 3.18. The obtained results indicate that the newly developed fiber is a feasible, selective, green, and cost-effective microextraction medium and could be successfully applied for extraction and determination of naphthalene-derived plant hormones in complex matrices. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Dispersibility and chemical bonds between multi-walled carbon nanotubes and poly(ether ether ketone) in nanocomposite fibers

    International Nuclear Information System (INIS)

    Yanmei, Jin; Haihui, Liu; Ning, Wang; Lichen, Hou; Xing-Xiang, Zhang

    2012-01-01

    A series of multi-walled carbon nanotubes (MWNTs)/poly(ether ether ketone)(PEEK) nanocomposite fibers were fabricated by mixing, melt extruding PEEK with different loadings and species of MWNTs, and melt-spun the blended chips. Nanocomposite fibers were heat-stretched and heat-treated. The morphology and dispersibility of MWNTs in nanocomposite fibers were observed using a field emission environmental scanning electron microscope (FESEM) and a transmission electron microscope (TEM). The thermal and crystallization behavior of nanocomposite fibers were characterized using differential scanning calorimetry (DSC) and an X-ray diffractometer (XRD). Mechanical properties were tested using a tensile strength tester. MWNTs tend to aggregate when the loading exceeds 0.8 wt%. Functional groups on MWNTs improve the hydrophobicity and the dispersibility of MWNTs in PEEK matrix. The enhancement of mechanical properties depends on the loading and species of functional groups. The most effectively reinforced effect is in the sequence, carboxylic MWNTs (MWNT–COOH) > hydroxyl MWNTs (MWNT–OH) > MWNTs, which can be explained by the strong hydrogen bonding and the affinity between MWNT–COOH and PEEK, MWNT–OH and PEEK, and possible formation of a chemical bond between MWNT–COOH and PEEK. A nanocomposite fiber with excellent mechanical property was fabricated using 0.8 wt% MWNT–COOH as filler. The Young's modulus is 1.7 GPa; and the stress is 648 MPa. -- Highlights: ► Functional groups on MWNTs improve their hydrophobility and dispersability. ► Mechanical properties depend on the content and species of the functional groups. ► The reinforced effect is in the sequence, carboxylic MWNTs > hydroxyl MWNTs > MWNTs. ► The strength behavior was result of hydrogen bond, affinity and chemical bond. ► Dispersability of MWNTs in matrix was analyzed by calculating solubility parameter.

  2. Conducting carbonized polyaniline nanotubes

    International Nuclear Information System (INIS)

    Mentus, Slavko; Ciric-Marjanovic, Gordana; Trchova, Miroslava; Stejskal, Jaroslav

    2009-01-01

    Conducting nitrogen-containing carbon nanotubes were synthesized by the carbonization of self-assembled polyaniline nanotubes protonated with sulfuric acid. Carbonization was carried out in a nitrogen atmosphere at a heating rate of 10 deg. C min -1 up to a maximum temperature of 800 deg. C. The carbonized polyaniline nanotubes which have a typical outer diameter of 100-260 nm, with an inner diameter of 20-170 nm and a length extending from 0.5 to 0.8 μm, accompanied with very thin nanotubes with outer diameters of 8-14 nm, inner diameters 3.0-4.5 nm and length extending from 0.3 to 1.0 μm, were observed by scanning and transmission electron microscopies. Elemental analysis showed 9 wt% of nitrogen in the carbonized product. Conductivity of the nanotubular PANI precursor, amounting to 0.04 S cm -1 , increased to 0.7 S cm -1 upon carbonization. Molecular structure of carbonized polyaniline nanotubes has been analyzed by FTIR and Raman spectroscopies, and their paramagnetic characteristics were compared with the starting PANI nanotubes by EPR spectroscopy.

  3. Conducting carbonized polyaniline nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Mentus, Slavko; Ciric-Marjanovic, Gordana [Faculty of Physical Chemistry, University of Belgrade, Studentski trg 12-16, 11158 Belgrade (Serbia); Trchova, Miroslava; Stejskal, Jaroslav [Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovsky Square 2, 162 06 Prague 6 (Czech Republic)], E-mail: gordana@ffh.bg.ac.rs

    2009-06-17

    Conducting nitrogen-containing carbon nanotubes were synthesized by the carbonization of self-assembled polyaniline nanotubes protonated with sulfuric acid. Carbonization was carried out in a nitrogen atmosphere at a heating rate of 10 deg. C min{sup -1} up to a maximum temperature of 800 deg. C. The carbonized polyaniline nanotubes which have a typical outer diameter of 100-260 nm, with an inner diameter of 20-170 nm and a length extending from 0.5 to 0.8 {mu}m, accompanied with very thin nanotubes with outer diameters of 8-14 nm, inner diameters 3.0-4.5 nm and length extending from 0.3 to 1.0 {mu}m, were observed by scanning and transmission electron microscopies. Elemental analysis showed 9 wt% of nitrogen in the carbonized product. Conductivity of the nanotubular PANI precursor, amounting to 0.04 S cm{sup -1}, increased to 0.7 S cm{sup -1} upon carbonization. Molecular structure of carbonized polyaniline nanotubes has been analyzed by FTIR and Raman spectroscopies, and their paramagnetic characteristics were compared with the starting PANI nanotubes by EPR spectroscopy.

  4. Determination of Pyrethroids in Tea Brew by GC-MS Combined with SPME with Multiwalled Carbon Nanotube Coated Fiber

    Directory of Open Access Journals (Sweden)

    Dongxia Ren

    2018-01-01

    Full Text Available A new method has been developed to simultaneously determine 7 pyrethroid residues in tea brew using gas chromatography-mass spectrometry (GC-MS combined with solid phase microextraction (SPME with multiwalled carbon nanotubes (MWCNTs coated fiber. The MWCNTs coated fiber of SPME was homemade by using stainless steel wire as coating carrier and polyacrylonitrile (PAN solution as adhesive glue. Under the optimized conditions, a good linearity was shown for bifenthrin, fenpropathrin, permethrin, and cyfluthrin in 1–50 ng mL−1 and for cypermethrin, fenvalerate, and deltamethrin in 5–50 ng mL−1. The correlation coefficients were in the range of 0.9948–0.9999. The average recoveries of 7 pyrethroids were 94.2%–107.3% and the relative standard deviations (RSDs were less than 15%. The detection limit of the method ranged from 0.12 to 1.65 ng mL−1. The tea brew samples made from some commercial tea samples were analyzed. Among them, bifenthrin, fenpropathrin, and permethrin were found. The results show that the method is rapid and sensitive and requires low organic reagent consumption, which can be well used for the detection of the pyrethroids in tea brew.

  5. Determination of Pyrethroids in Tea Brew by GC-MS Combined with SPME with Multiwalled Carbon Nanotube Coated Fiber.

    Science.gov (United States)

    Ren, Dongxia; Sun, Chengjun; Ma, Guanqun; Yang, Danni; Zhou, Chen; Xie, Jiayu; Li, Yongxin

    2018-01-01

    A new method has been developed to simultaneously determine 7 pyrethroid residues in tea brew using gas chromatography-mass spectrometry (GC-MS) combined with solid phase microextraction (SPME) with multiwalled carbon nanotubes (MWCNTs) coated fiber. The MWCNTs coated fiber of SPME was homemade by using stainless steel wire as coating carrier and polyacrylonitrile (PAN) solution as adhesive glue. Under the optimized conditions, a good linearity was shown for bifenthrin, fenpropathrin, permethrin, and cyfluthrin in 1-50 ng mL -1 and for cypermethrin, fenvalerate, and deltamethrin in 5-50 ng mL -1 . The correlation coefficients were in the range of 0.9948-0.9999. The average recoveries of 7 pyrethroids were 94.2%-107.3% and the relative standard deviations (RSDs) were less than 15%. The detection limit of the method ranged from 0.12 to 1.65 ng mL -1 . The tea brew samples made from some commercial tea samples were analyzed. Among them, bifenthrin, fenpropathrin, and permethrin were found. The results show that the method is rapid and sensitive and requires low organic reagent consumption, which can be well used for the detection of the pyrethroids in tea brew.

  6. Mode-locked ytterbium fiber lasers using a large modulation depth carbon nanotube saturable absorber without an additional spectral filter

    International Nuclear Information System (INIS)

    Pan, Y Z; Miao, J G; Liu, W J; Huang, X J; Wang, Y B

    2014-01-01

    We demonstrate an all-normal-dispersion ytterbium (Yb)-doped fiber laser mode-locked by a higher modulation depth carbon nanotube saturable absorber (CNT-SA) based on an evanescent field interaction scheme. The laser cavity consists of pure normal dispersion fibers without dispersion compensation and an additional spectral filter. It is exhibited that the higher modulation depth CNT-SA could contribute to stabilize the mode-locking operation within a limited range of pump power and generate the highly chirped pulses with a high-energy level in the cavity with large normal dispersion and strong nonlinearity. Stable mode-locked pulses with a maximal energy of 29 nJ with a 5.59 MHz repetition rate at the operating wavelength around 1085 nm have been obtained. The maximal time-bandwidth product is 262.4. The temporal and spectral characteristics of pulses versus pump power are demonstrated. The experimental results suggest that the CNT-SA provides a sufficient nonlinear loss to compensate high nonlinearity and catch up the gain at a different pump power and thus leads to the stable mode locking. (letter)

  7. Interface enhancement of glass fiber reinforced vinyl ester composites with flame-synthesized carbon nanotubes and its enhancing mechanism.

    Science.gov (United States)

    Liao, Lingmin; Wang, Xiao; Fang, Pengfei; Liew, Kim Meow; Pan, Chunxu

    2011-02-01

    Interface enhancement with carbon nanotubes (CNTs) provides a promising approach for improving shock strength and toughness of glass fiber reinforced plastic (GFRP) composites. The effects of incorporating flame-synthesized CNTs (F-CNTs) into GFRP were studied, including on hand lay-up preparation, microstructural characterization, mechanical properties, fracture morphologies, and theoretical calculation. The experimental results showed that: (1) the impact strength of the GFRP modified by F-CNTs increased by more than 15% over that of the GFRP modified by CNTs from chemical vapor deposition; and (2) with the F-CNT enhancement, no interfacial debonding was observed at the interface between the fiber and resin matrix on the GFRP fracture surface, which indicated strong adhesive strength between them. The theoretical calculation revealed that the intrinsic characteristics of the F-CNTs, including lower crystallinity with a large number of defects and chemical functional groups on the surface, promoted their surface activity and dispersibility at the interface, which improved the interfacial bond strength of GFRP.

  8. Surface decoration of short-cut polyimide fibers with multi-walled carbon nanotubes and their application for reinforcement of lightweight PC/ABS composites

    Science.gov (United States)

    Zhang, Le; Han, Enlin; Wu, Yulun; Wang, Xiaodong; Wu, Dezhen

    2018-06-01

    The surface decoration of short-cut polyimide (PI) fibers with multi-walled carbon nanotubes (MWCNTs) was performed by fabricating a polydopamine (PDA) coating layer on the fiber surface and then immobilizing MWCNTs onto the coating layer via covalent bonding. This successful surface decoration was confirmed by scanning electron microscopy, X-ray photoelectron spectroscopy, Fourier-transform infrared microscopy and static water contact angle. The application of the surface-decorated PI fibers as reinforcing fibers for reinforcement of polycarbonate (PC)/acrylonitrile-butadiene-styrene copolymer (ABS) alloy was investigated, which indicated that the MWCNTs-decorated PI fibers not only could effectively reinforce the PC/ABS alloy but also generated a significant lightweighting effect on the resulting composites. The maximum mechanical properties were achieved for the composites at a fiber content of 20 wt.% and a fiber length of 3 mm. This significant reinforcement effect is attributed to the enhancement of interaction bonding strength between the fibers and matrix as a result of the surface decoration of PI fibers with MWCNTs. The morphological investigation suggested that fiber rupture was the major energy dissipation mechanism in the tensile and impact failures, whereas fiber debonding and pullout were partly involved in the fracture energy dissipation. In addition, the presence of surface-decorated PI fibers slightly enhanced the thermal stability and load bearing capability of composites. This work can provide a type of high-performance lightweight composite material for automobile and aviation industries.

  9. Hydroxyapatite growth on multiwall carbon nanotubes grown on titanium fibers from a titanium sheet

    KAUST Repository

    Chetibi, Loubna

    2013-09-27

    Nano-hydroxyapatite (HA) was grown on functionalized multiwalled carbon nanotubes (MWCNTs) deposited on TiO2 nanofibers (NFs) that were hydrothermally grown on Ti metal sheets. The HA was electrochemically grown on the MWCNTs/TiO2 porous layer. It was found that the HA grows on the MWCNTs/TiO2 NFs in the form of dense coating with nanorice grain-shaped. The incorporation of MWCNTs between HA and TiO2 NFs has led to higher adhesion strength as measured by micro-scratching test indicating the benefit of MWCNTs on the improving the bonding strength of HA layer. The obtained coatings exhibit excellent corrosion resistance in simulated body fluid. It is expected that this simple route for preparing the new HA/MWCNTs/TiO2/Ti-layered structure might be used not only in the biomedical field, but also in catalysis and biological sensing among others. © 2013 Springer Science+Business Media New York.

  10. Hydroxyapatite growth on multiwall carbon nanotubes grown on titanium fibers from a titanium sheet

    KAUST Repository

    Chetibi, Loubna; Achour, Amine; Peszke, Jerzy; Hamana, Djamel; Achour, Slimane

    2013-01-01

    Nano-hydroxyapatite (HA) was grown on functionalized multiwalled carbon nanotubes (MWCNTs) deposited on TiO2 nanofibers (NFs) that were hydrothermally grown on Ti metal sheets. The HA was electrochemically grown on the MWCNTs/TiO2 porous layer. It was found that the HA grows on the MWCNTs/TiO2 NFs in the form of dense coating with nanorice grain-shaped. The incorporation of MWCNTs between HA and TiO2 NFs has led to higher adhesion strength as measured by micro-scratching test indicating the benefit of MWCNTs on the improving the bonding strength of HA layer. The obtained coatings exhibit excellent corrosion resistance in simulated body fluid. It is expected that this simple route for preparing the new HA/MWCNTs/TiO2/Ti-layered structure might be used not only in the biomedical field, but also in catalysis and biological sensing among others. © 2013 Springer Science+Business Media New York.

  11. Multifunctional Carbon Nanotube-Based Sensors for Damage Detection and Self Healing in Structural Composites

    Science.gov (United States)

    2010-10-29

    established based on the concept of equipotential surface . The effect of nanotube length on the critical charge level is plotted in Fig. 17. Fig...walled carbon nanotubes was used to develop composites with agglomerated regions of nanotubes at the fiber surface [3]. An image of the nanotube...coating on the surface of two E-glass fibers is shown in Fig. 5. Fig. 5. (a) Carbon nanotube agglomerates on the surface of glass fibers in the

  12. The Electrochemical Behavior of Carbon Fiber Microelectrodes Modified with Carbon Nanotubes Using a Two-Step Electroless Plating/Chemical Vapor Deposition Process

    Directory of Open Access Journals (Sweden)

    Longsheng Lu

    2017-03-01

    Full Text Available Carbon fiber microelectrode (CFME has been extensively applied in the biosensor and chemical sensor domains. In order to improve the electrochemical activity and sensitivity of the CFME, a new CFME modified with carbon nanotubes (CNTs, denoted as CNTs/CFME, was fabricated and investigated. First, carbon fiber (CF monofilaments grafted with CNTs (simplified as CNTs/CFs were fabricated in two key steps: (i nickel electroless plating, followed by (ii chemical vapor deposition (CVD. Second, a single CNTs/CF monofilament was selected and encapsulated into a CNTs/CFME with a simple packaging method. The morphologies of as-prepared CNTs/CFs were characterized by scanning electron microscopy. The electrochemical properties of CNTs/CFMEs were measured in potassium ferrocyanide solution (K4Fe(CN6, by using a cyclic voltammetry (CV and a chronoamperometry method. Compared with a bare CFME, a CNTs/CFME showed better CV curves with a higher distinguishable redox peak and response current; the higher the CNT content was, the better the CV curves were. Because the as-grown CNTs significantly enhanced the effective electrode area of CNTs/CFME, the contact area between the electrode and reactant was enlarged, further increasing the electrocatalytic active site density. Furthermore, the modified microelectrode displayed almost the same electrochemical behavior after 104 days, exhibiting remarkable stability and outstanding reproducibility.

  13. 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

  14. Design of Electrically Conductive Structural Composites by Modulating Aligned CVD-Grown Carbon Nanotube Length on Glass Fibers.

    Science.gov (United States)

    He, Delong; Fan, Benhui; Zhao, Hang; Lu, Xiaoxin; Yang, Minhao; Liu, Yu; Bai, Jinbo

    2017-01-25

    Function-integration in glass fiber (GF) reinforced polymer composites is highly desired for developing lightweight structures and devices with improved performance and structural health monitoring. In this study, homogeneously aligned carbon nanotube (CNT) shell was in situ grafted on GF by chemical vapor deposition (CVD). It was demonstrated that the CNT shell thickness and weight fraction can be modulated by controlling the CVD conditions. The obtained hierarchical CNTs-GF/epoxy composites show highly improved electrical conductivity and thermo-mechanical and flexural properties. The composite through-plane and in-plane electrical conductivities increase from a quasi-isolator value to ∼3.5 and 100 S/m, respectively, when the weight fraction of CNTs grafted on GF fabric varies from 0% to 7%, respectively. Meanwhile, the composite storage modulus and flexural modulus and strength improve as high as 12%, 21%, and 26%, respectively, with 100% retention of the glass transition temperature. The reinforcing mechanisms are investigated by analyzing the composite microstructure and the interfacial adhesion and wetting properties of CNTs-GF hybrids. Moreover, the specific damage-related resistance variation characteristics could be employed to in situ monitor the structural health state of the composites. The outstanding electrical and structural properties of the CNTs-GF composites were due to the specific interfacial and interphase structures created by homogeneously grafting aligned CNTs on each GF of the fabric.

  15. Gas-Phase Functionalization of Macroscopic Carbon Nanotube Fiber Assemblies: Reaction Control, Electrochemical Properties, and Use for Flexible Supercapacitors.

    Science.gov (United States)

    Iglesias, Daniel; Senokos, Evgeny; Alemán, Belén; Cabana, Laura; Navío, Cristina; Marcilla, Rebeca; Prato, Maurizio; Vilatela, Juan J; Marchesan, Silvia

    2018-02-14

    The assembly of aligned carbon nanotubes (CNTs) into fibers (CNTFs) is a convenient approach to exploit and apply the unique physico-chemical properties of CNTs in many fields. CNT functionalization has been extensively used for its implementation into composites and devices. However, CNTF functionalization is still in its infancy because of the challenges associated with preservation of CNTF morphology. Here, we report a thorough study of the gas-phase functionalization of CNTF assemblies using ozone which was generated in situ from a UV source. In contrast with liquid-based oxidation methods, this gas-phase approach preserves CNTF morphology, while notably increasing its hydrophilicity. The functionalized material is thoroughly characterized by Raman spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, and scanning electron microscopy. Its newly acquired hydrophilicity enables CNTF electrochemical characterization in aqueous media, which was not possible for the pristine material. Through comparison of electrochemical measurements in aqueous electrolytes and ionic liquids, we decouple the effects of functionalization on pseudocapacitive reactions and quantum capacitance. The functionalized CNTF assembly is successfully used as an active material and a current collector in all-solid supercapacitor flexible devices with an ionic liquid-based polymer electrolyte.

  16. Voltage-Gated Transport of Nanoparticles across Free-Standing All-Carbon-Nanotube-Based Hollow-Fiber Membranes.

    Science.gov (United States)

    Wei, Gaoliang; Quan, Xie; Chen, Shuo; Fan, Xinfei; Yu, Hongtao; Zhao, Huimin

    2015-07-15

    Understanding the mechanism underlying controllable transmembrane transport observed in biological membranes benefits the development of next-generation separation membranes for a variety of important applications. In this work, on the basis of common structural features of cell membranes, a very simple biomimetic membrane system exhibiting gated transmembrane performance has been constructed using all-carbon-nanotube (CNT)-based hollow-fiber membranes. The conductive CNT membranes with hydrophobic pore channels can be positively or negatively charged and are consequently capable of regulating the transport of nanoparticles across their pore channels by their "opening" or "closing". The switch between penetration and rejection of nanoparticles through/by CNT membranes is of high efficiency and especially allows dynamic control. The underlying mechanism is that CNT pore channels with different polarities can prompt or prevent the formation of their noncovalent interactions with charged nanoparticles, resulting in their rejection or penetration by/through the CNT membranes. The theory about noncovalent interactions and charged pore channels may provide new insight into understanding the complicated ionically and bimolecularly gated transport across cell membranes and can contribute to many other important applications beyond the water purification and resource recovery demonstrated in this study.

  17. 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

  18. Influence of carbon nanotube (CNT) on the mechanical properties of LLDPE/CNT nanocomposite fibers

    KAUST Repository

    Mezghani, Khaled; Farooqui, Muhammad Fahad; Furquan, Sarfaraz; Ali, Muhammad

    2011-01-01

    The present study shows the effect of adding CNT to linear low-density polyethylene (LLDPE) to produce LLDPE/CNT nanocomposite fibers. The LLDPE/CNT fibers were produced by melt extrusion process using a twin-screw extruder, in a controlled temperature from 160 °C to 275 °C. Further, melt extrusion process was followed by drawing of fibers at the room temperature. Three different weight percentages, 0.08, 0.3 and 1 wt.% of CNT were studied for producing nanocomposite fibers. The addition of 1 wt.% CNT in the LLDPE fiber has increased the tensile strength by 38% (350 MPa). The addition of 0.08 and 0.3 wt.% CNT in the fiber matrix has improved the ductility by 87% and 122%, respectively. Similarly, improvement in the toughness was observed by 63% and 105% for LLDPE fibers with 0.08 wt.% and 0.3 wt.% CNT respectively. The increase in the mechanical properties of the composite fibers was attributed to the alignment and distribution of CNT in the LLDPE matrix. The dispersion of CNT in the polymeric matrix has been revealed by SEM. The study shows that the small addition of CNT when properly mixed and aligned will increase the mechanical properties of pristine polymer fibers. © 2011 Elsevier B.V. All rights reserved.

  19. Influence of carbon nanotube (CNT) on the mechanical properties of LLDPE/CNT nanocomposite fibers

    KAUST Repository

    Mezghani, Khaled

    2011-12-01

    The present study shows the effect of adding CNT to linear low-density polyethylene (LLDPE) to produce LLDPE/CNT nanocomposite fibers. The LLDPE/CNT fibers were produced by melt extrusion process using a twin-screw extruder, in a controlled temperature from 160 °C to 275 °C. Further, melt extrusion process was followed by drawing of fibers at the room temperature. Three different weight percentages, 0.08, 0.3 and 1 wt.% of CNT were studied for producing nanocomposite fibers. The addition of 1 wt.% CNT in the LLDPE fiber has increased the tensile strength by 38% (350 MPa). The addition of 0.08 and 0.3 wt.% CNT in the fiber matrix has improved the ductility by 87% and 122%, respectively. Similarly, improvement in the toughness was observed by 63% and 105% for LLDPE fibers with 0.08 wt.% and 0.3 wt.% CNT respectively. The increase in the mechanical properties of the composite fibers was attributed to the alignment and distribution of CNT in the LLDPE matrix. The dispersion of CNT in the polymeric matrix has been revealed by SEM. The study shows that the small addition of CNT when properly mixed and aligned will increase the mechanical properties of pristine polymer fibers. © 2011 Elsevier B.V. All rights reserved.

  20. Making a commercial carbon fiber cloth having comparable capacitances to carbon nanotubes and graphene in supercapacitors through a "top-down" approach.

    Science.gov (United States)

    Zhang, Tianchang; Kim, Christine H J; Cheng, Yingwen; Ma, Yanwen; Zhang, Hongbo; Liu, Jie

    2015-02-21

    A "top-down" and scalable approach for processing carbon fiber cloth (CFC) into flexible and all-carbon electrodes with remarkable areal capacity and cyclic stability was developed. CFC is commercially available in large quantities but its use as an electrode material in supercapacitors is not satisfactory. The approach demonstrated in this work is based on the sequential treatment of CFC with KOH activation and high temperature annealing that can effectively improve its specific surface area to a remarkable 2780 m(2) g(-1) while at the same time achieving a good electrical conductivity of 320 S m(-1) without sacrificing its intrinsic mechanical strength and flexibility. The processed CFC can be directly used as an electrode for supercapacitors without any binders, conductive additives and current collectors while avoiding elaborate electrode processing steps to deliver a specific capacitance of ∼0.5 F cm(-2) and ∼197 F g(-1) with remarkable rate performance and excellent cyclic stability. The properties of these processed CFCs are comparable or better than graphene and carbon nanotube based electrodes. We further demonstrate symmetric solid-state supercapacitors based on these processed CFCs with very good flexibility. This "top-down" and scalable approach can be readily applied to other types of commercially available carbon materials and therefore can have a substantial significance for high performance supercapacitor devices.

  1. Electron diffraction from carbon nanotubes

    International Nuclear Information System (INIS)

    Qin, L-C

    2006-01-01

    The properties of a carbon nanotube are dependent on its atomic structure. The atomic structure of a carbon nanotube can be defined by specifying its chiral indices (u, v), that specify its perimeter vector (chiral vector), with which the diameter and helicity are also determined. The fine electron beam available in a modern transmission electron microscope (TEM) offers a unique probe to reveal the atomic structure of individual nanotubes. This review covers two aspects related to the use of the electron probe in the TEM for the study of carbon nanotubes: (a) to understand the electron diffraction phenomena for inter-pretation of the electron diffraction patterns of carbon nanotubes and (b) to obtain the chiral indices (u, v), of the carbon nanotubes from the electron diffraction patterns. For a nanotube of a given structure, the electron scattering amplitude from the carbon nanotube is first described analytically in closed form using the helical diffraction theory. From a known structure as given by the chiral indices (u, v), its electron diffraction pattern can be calculated and understood. The reverse problem, i.e. assignment of the chiral indices from an electron diffraction pattern of a carbon nanotube, is approached from the relationship between the electron scattering intensity distribution and the chiral indices (u, v). We show that electron diffraction patterns can provide an accurate and unambiguous assignment of the chiral indices of carbon nanotubes. The chiral indices (u, v) can be read indiscriminately with a high accuracy from the intensity distribution on the principal layer lines in an electron diffraction pattern. The symmetry properties of electron diffraction from carbon nanotubes and the electron diffraction from deformed carbon nanotubes are also discussed in detail. It is shown that 2mm symmetry is always preserved for single-walled carbon nanotubes, but it can break down for multiwalled carbon nanotubes under some special circumstances

  2. Carbon nanotube filters

    Science.gov (United States)

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

    2004-09-01

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

  3. Twisting dependent properties of twisted carbon nanotube fibers: microstructure and strain transfer factors

    International Nuclear Information System (INIS)

    Zhou, Jinyuan; Xie, Erqing; Sun, Gengzhi; Zhan, Zhaoyao; Zheng, Lianxi

    2014-01-01

    The dependences of twisting parameters on the electric and mechanical properties of twisted CNT fibers were systematically studied. Results from electric and mechanical measurements showed that twisting intensity is very effective to improve the electric and mechanical properties of CNT fibers. Further calculations combined with Raman results indicate that the twisting treatments, to a certain extent, can greatly enhance the strain transfer factors of the samples, which dominates the mechanical properties of CNT fibers. In addition, studies on the effect of twisting speeds suggested that lower twisting speed can lead to higher uniformity but lower performances in the electric and mechanical properties, higher twisting speed to higher Young’s modulus and higher conductance but lower uniformities. Ultra-strong uniform CNT fibers need to be prepared with a suitable twisting speed. (paper)

  4. Adhered Supported Carbon Nanotubes

    International Nuclear Information System (INIS)

    Johnson, Dale F.; Craft, Benjamin J.; Jaffe, Stephen M.

    2001-01-01

    Carbon nanotubes (NTs) in excess of 200 μm long are grown by catalytic pyrolysis of hydrocarbon vapors. The nanotubes grow continuously without the typical extinction due to catalyst encapsulation. A woven metal mesh supports the nanotubes creating a metal supported nanotube (MSNT) structure. The 140 μm wide mesh openings are completely filled by 70 nm diameter multiwalled nanotubes (MWNTs). The MWNTs are straight, uniform and highly crystalline. Their wall thickness is about 10 nm (30 graphite layers). The adherent NTs are not removed from the support in a Scotch tape pull test. A 12.5 cm 2 capacitor made from two MSNT structures immersed in 1 M KCl has a capacitance of 0.35 F and an equivalent series resistance of 0.18 Ω. Water flows through the MSNT at a flow velocity of 1 cm/min with a pressure drop of 15 inches of water. With the support removed, the MWNTs naturally form a carbon nanocomposite (CNC) paper with a specific area of 80 m 2 /gm, a bulk density of 0.21 g/cm 3 , an open pore fraction of 0.81, and a resistivity of 0.16 Ω-cm

  5. Energy dissipation and high-strain rate dynamic response of E-glass fiber composites with anchored carbon nanotubes

    Science.gov (United States)

    This study explores the mechanical properties of an E-glass fabric composite reinforced with anchored multi-walled carbon nanotubes (CNTs). The CNTs were grown on the E-glass fabric using a floating catalyst chemical vapor deposition procedure. The E-glass fabric with attached CNTs was then incorpor...

  6. Repetition frequency scaling of an all-polarization maintaining erbium-doped mode-locked fiber laser based on carbon nanotubes saturable absorber

    Energy Technology Data Exchange (ETDEWEB)

    Sotor, J., E-mail: jaroslaw.sotor@pwr.edu.pl; Sobon, G.; Abramski, K. M. [Laser and Fiber Electronics Group, Wroclaw University of Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw (Poland); Jagiello, J.; Lipinska, L. [Institute of Electronic Materials Technology, Wolczynska 133, 01-919 Warsaw (Poland)

    2015-04-07

    We demonstrate an all-polarization maintaining (PM), mode-locked erbium (Er)-doped fiber laser based on a carbon nanotubes (CNT) saturable absorber (SA). The laser resonator was maximally simplified by using only one passive hybrid component and a pair of fiber connectors with deposited CNTs. The repetition frequency (F{sub rep}) of such a cost-effective and self-starting mode-locked laser was scaled from 54.3 MHz to 358.6 MHz. The highest F{sub rep} was obtained when the total cavity length was shortened to 57 cm. The laser allows ultrashort pulse generation with the duration ranging from 240 fs to 550 fs. Because the laser components were based on PM fibers the laser was immune to the external perturbations and generated laniary polarized light with the degree of polarization (DOP) of 98.7%.

  7. 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.

  8. Influence of the Hybrid Combination of Multiwalled Carbon Nanotubes and Graphene Oxide on Interlaminar Mechanical Properties of Carbon Fiber/Epoxy Laminates

    Science.gov (United States)

    Rodríguez-González, J. A.; Rubio-González, C.; Jiménez-Mora, M.; Ramos-Galicia, L.; Velasco-Santos, C.

    2017-10-01

    An effective strategy to improve the mode I and mode II interlaminar fracture toughness (G IC and G IIC ) of unidirectional carbon fiber/epoxy (CF/E) laminates using a hybrid combination of multiwalled carbon nanotubes (MWCNTs) and graphene oxide (GO) is reported. Double cantilever beam (DCB) and end notched flexure (ENF) tests were conducted to evaluate the G IC and G IIC of the CF/E laminates fabricated with sprayed MWCNTs, GO and MWCNTs/GO hybrid. Scanning electron microscopy was employed to observe the fracture surfaces of tested DCB and ENF specimens. Experimental results showed the positive effect on the G IC and G IIC by 17% and 14% improvements on CF/E laminates with 0.25 wt.% MWCNTs/GO hybrid content compared to the neat CF/E. Also, the interlaminar shear strength value was increased for MWCNTs/GO-CF/E laminates. A synergetic effect between MWCNTs and GO resulted in improved interlaminar mechanical properties of CF/E laminates made by prepregs.

  9. The Surface Interface Characteristics of Vertically Aligned Carbon Nanotube and Graphitic Carbon Fiber Arrays Grown by Thermal and Plasma Enhanced Chemical Vapor Deposition

    Science.gov (United States)

    Delzeit, Lance; Nguyen, Cattien; Li, Jun; Han, Jie; Meyyappan, M.

    2002-01-01

    The development of nano-arrays for sensors and devices requires the growth of arrays with the proper characteristics. One such application is the growth of vertically aligned carbon nanotubes (CNTs) and graphitic carbon fibers (GCFs) for the chemical attachment of probe molecules. The effectiveness of such an array is dependent not only upon the effectiveness of the probe and the interface between that probe and the array, but also the array and the underlaying substrate. If that array is a growth of vertically aligned CNTs or GCFs then the attachment of that array to the surface is of the utmost importance. This attachment provides the mechanical stability and durability of the array, as well as, the electrical properties of that array. If the detection is to be acquired through an electrical measurement, then the appropriate resistance between the array and the surface need to be fabricated into the device. I will present data on CNTs and GCFs grown from both thermal and plasma enhanced chemical vapor deposition. The focus will be on the characteristics of the metal film from which the CNTs and GCFs are grown and the changes that occur due to changes within the growth process.

  10. Dual-opposite multi-walled carbon nanotube modified carbon fiber microelectrode for microfluidic chip-capillary electrophoresis determination of methyl parathion metabolites in human urine.

    Science.gov (United States)

    Du, Fuying; Fung, Ying-Sing

    2018-03-03

    Methyl parathion (MP) is a highly toxic organophosphate and its exposure may lead to substantial adverse effects to human health. The existence of 4-nitrophenol (4-NP) in the form of free phenol, glucuronide (4-NP-G) or as a sulfate ester (4-NP-S) can be used as biomarkers to assess the duration and extent of MP exposure. In this work, a MC-CE device incorporating post-CE amperometric detection using multi-walled carbon nanotubes (MWNTs) modified carbon fiber microelectrode (CFME) was fabricated and assessed for simultaneous determination of 4-NP, 4-NP-G, and 4-NP-S in human urine. The detection sensitivity and stability was greatly enhanced by the modification of MWNTs. The capability of the MC-CE device with dual MWNTs modified CFME for detecting impurity was assessed and reliability established by high recoveries from 95 to 97% for spiked MP biomarkers. The method developed is shown to provide a simple, sensitive, and reliable means for monitoring 4-NP, 4-NP-G, and 4-NP-S in human urine. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Interfacial adhesion improvement in carbon fiber/carbon nanotube reinforced hybrid composites by the application of a reactive hybrid resin initiated by gamma irradiation

    Science.gov (United States)

    Szebényi, G.; Faragó, D.; Lámfalusi, Cs.; Göbl, R.

    2018-04-01

    Interfacial adhesion is a key factor in composite materials. The effective co-working of the reinforcing materials and matrix is essential for the proper load transfer between them, and to achieve the desired reinforcing effect. In case of nanocomposites, especially carbon nanotube (CNT) reinforced nanocomposites the adhesion between the CNTs and the polymer matrix is poor. To improve the interfacial adhesion and exploit the reinforcing effect of these nanoparticles a two step curable epoxy (EP)/vinylester (VE) hybrid resin system was developed where the EP is cured using hardener in the first step, during the composite production, and in the second step the curing of the VE is initiated by gamma irradiation, which also activates the reinforcing materials and the cured matrix component. A total of six carbon fiber reinforced composite systems were compared with neat epoxy and EP/VE hybrid matrices with and without chemical initiator and MWCNT nano-reinforcement. The effect of gamma irradiation was investigated at four absorbed dose levels. According to our three point bending and interlaminar shear test results the adhesion has improved between all constituents of the composite system. It was demonstrated that gamma irradiation has beneficial effect on the static mechanical, especially interlaminar properties of both micro- and nanocomposites in terms of modulus, strength and interlaminar shear strength.

  12. Carbon nanotube plane fastener

    Directory of Open Access Journals (Sweden)

    Kaori Hirahara

    2011-12-01

    Full Text Available We report a feature of carbon nanotubes (CNTs that arises when the surfaces of two vertically-aligned CNT brushes are pressed together. Adhesion between the CNTs creates a plane fastener-like device. Observations from scanning electron microscopy and measurements of adhesion properties indicate a device-dependence on CNT density and shape near the tip region. Among other applications, such fasteners have the potential to attach small components onto micron-sized electronic devices.

  13. Carbon nanotube network varactor

    International Nuclear Information System (INIS)

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

    2015-01-01

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

  14. Gas chromatographic determination of polycyclic aromatic hydrocarbons in water and smoked rice samples after solid-phase microextraction using multiwalled carbon nanotube loaded hollow fiber.

    Science.gov (United States)

    Matin, Amir Abbas; Biparva, Pourya; Gheshlaghi, Mohammad

    2014-12-29

    A novel solid-phase microextraction fiber was prepared based on multiwalled carbon nanotubes (MWCNTs) loaded on hollow fiber membrane pores. Stainless steel wire was used as unbreakable support. The major advantages of the proposed fiber are its (a) high reproducibility due to the uniform structure of the hollow fiber membranes, (b) high extraction capacity related to the porous structure of the hollow fiber and outstanding adsorptive characteristics of MWCNTs. The proposed fiber was applied for the microextraction of five representative polycyclic aromatic hydrocarbons (PAHs) from aqueous media (river and hubble-bubble water) and smoked rice samples followed by gas chromatographic determination. Analytical merits of the method, including high correlation coefficients [(0.9963-0.9992) and (0.9982-0.9999)] and low detection limits [(9.0-13.0ngL(-1)) and (40.0-150.0ngkg(-1))] for water and rice samples, respectively, made the proposed method suitable for the ultra-trace determination of PAHs. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Quantitative analysis of mechanical and electrostatic properties of poly(lactic) acid fibers and poly(lactic) acid—carbon nanotube composites using atomic force microscopy

    International Nuclear Information System (INIS)

    Iqbal, Qais; Bernstein, Peter; Zhu, Yazhe; Rahamim, Joseph; Cebe, Peggy; Staii, Cristian

    2015-01-01

    We use atomic force microscopy (AFM) to perform a systematic quantitative characterization of the elastic modulus and dielectric constant of poly(L-lactic acid) electrospun nanofibers (PLLA), as well as composites of PLLA fibers with 1.0 wt% embedded multiwall carbon nanotubes (MWCNTs–PLLA). The elastic moduli are measured in the fiber skin region via AFM nanoindentation, and the dielectric constants are determined by measuring the phase shifts obtained via electrostatic force microscopy (EFM). We find that the average value for the elastic modulus for PLLA fibers is (9.8 ± 0.9) GPa, which is a factor of 2 larger than the measured average elastic modulus for MWCNT–PLLA composites (4.1 ± 0.7) GPa. We also use EFM to measure dielectric constants for both types of fibers. These measurements show that the dielectric constants of the MWCNT–PLLA fibers are significantly larger than the corresponding values obtained for PLLA fiber. This result is consistent with the higher polarizability of the MWCNT–PLLA composites. The measurement methods presented are general, and can be applied to determine the mechanical and electrical properties of other polymers and polymer nanocomposites. (paper)

  16. Spinnability and Characteristics of Polyvinylidene Fluoride (PVDF)-based Bicomponent Fibers with a Carbon Nanotube (CNT) Modified Polypropylene Core for Piezoelectric Applications.

    Science.gov (United States)

    Glauß, Benjamin; Steinmann, Wilhelm; Walter, Stephan; Beckers, Markus; Seide, Gunnar; Gries, Thomas; Roth, Georg

    2013-07-03

    This research explains the melt spinning of bicomponent fibers, consisting of a conductive polypropylene (PP) core and a piezoelectric sheath (polyvinylidene fluoride). Previously analyzed piezoelectric capabilities of polyvinylidene fluoride (PVDF) are to be exploited in sensor filaments. The PP compound contains a 10 wt % carbon nanotubes (CNTs) and 2 wt % sodium stearate (NaSt). The sodium stearate is added to lower the viscosity of the melt. The compound constitutes the fiber core that is conductive due to a percolation CNT network. The PVDF sheath's piezoelectric effect is based on the formation of an all-trans conformation β phase, caused by draw-winding of the fibers. The core and sheath materials, as well as the bicomponent fibers, are characterized through different analytical methods. These include wide-angle X-ray diffraction (WAXD) to analyze crucial parameters for the development of a crystalline β phase. The distribution of CNTs in the polymer matrix, which affects the conductivity of the core, was investigated by transmission electron microscopy (TEM). Thermal characterization is carried out by conventional differential scanning calorimetry (DSC). Optical microscopy is used to determine the fibers' diameter regularity (core and sheath). The materials' viscosity is determined by rheometry. Eventually, an LCR tester is used to determine the core's specific resistance.

  17. 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.

  18. 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

  19. Mechanical properties of carbon nanotubes

    Science.gov (United States)

    Salvetat, J.-P.; Bonard, J.-M.; Thomson, N. H.; Kulik, A. J.; Forró, L.; Benoit, W.; Zuppiroli, L.

    A variety of outstanding experimental results on the elucidation of the elastic properties of carbon nanotubes are fast appearing. These are based mainly on the techniques of high-resolution transmission electron microscopy (HRTEM) and atomic force microscopy (AFM) to determine the Young's moduli of single-wall nanotube bundles and multi-walled nanotubes, prepared by a number of methods. These results are confirming the theoretical predictions that carbon nanotubes have high strength plus extraordinary flexibility and resilience. As well as summarising the most notable achievements of theory and experiment in the last few years, this paper explains the properties of nanotubes in the wider context of materials science and highlights the contribution of our research group in this rapidly expanding field. A deeper understanding of the relationship between the structural order of the nanotubes and their mechanical properties will be necessary for the development of carbon-nanotube-based composites. Our research to date illustrates a qualitative relationship between the Young's modulus of a nanotube and the amount of disorder in the atomic structure of the walls. Other exciting results indicate that composites will benefit from the exceptional mechanical properties of carbon nanotubes, but that the major outstanding problem of load transfer efficiency must be overcome before suitable engineering materials can be produced.

  20. Carbon nanotube based photocathodes

    International Nuclear Information System (INIS)

    Hudanski, Ludovic; Minoux, Eric; Schnell, Jean-Philippe; Xavier, Stephane; Pribat, Didier; Legagneux, Pierre; Gangloff, Laurent; Teo, Kenneth B K; Robertson, John; Milne, William I

    2008-01-01

    This paper describes a novel photocathode which is an array of vertically aligned multi-walled carbon nanotubes (MWCNTs), each MWCNT being associated with one p-i-n photodiode. Unlike conventional photocathodes, the functions of photon-electron conversion and subsequent electron emission are physically separated. Photon-electron conversion is achieved with p-i-n photodiodes and the electron emission occurs from the MWCNTs. The current modulation is highly efficient as it uses an optically controlled reconfiguration of the electric field at the MWCNT locations. Such devices are compatible with high frequency and very large bandwidth operation and could lead to their application in compact, light and efficient microwave amplifiers for satellite telecommunication. To demonstrate this new photocathode concept, we have fabricated the first carbon nanotube based photocathode using silicon p-i-n photodiodes and MWCNT bunches. Using a green laser, this photocathode delivers 0.5 mA with an internal quantum efficiency of 10% and an I ON /I OFF ratio of 30

  1. Carbon nanotube array actuators

    International Nuclear Information System (INIS)

    Geier, S; Mahrholz, T; Wierach, P; Sinapius, M

    2013-01-01

    Experimental investigations of highly vertically aligned carbon nanotubes (CNTs), also known as CNT-arrays, are the main focus of this paper. The free strain as result of an active material behavior is analyzed via a novel experimental setup. Previous test experiences of papers made of randomly oriented CNTs, also called Bucky-papers, reveal comparably low free strain. The anisotropy of aligned CNTs promises better performance. Via synthesis techniques like chemical vapor deposition (CVD) or plasma enhanced CVD (PECVD), highly aligned arrays of multi-walled carbon nanotubes (MWCNTs) are synthesized. Two different types of CNT-arrays are analyzed, morphologically first, and optically tested for their active characteristics afterwards. One type of the analyzed arrays features tube lengths of 750–2000 μm with a large variety of diameters between 20 and 50 nm and a wave-like CNT-shape. The second type features a maximum, almost uniform, length of 12 μm and a constant diameter of 50 nm. Different CNT-lengths and array types are tested due to their active behavior. As result of the presented tests, it is reported that the quality of orientation is the most decisive property for excellent active behavior. Due to their alignment, CNT-arrays feature the opportunity to clarify the actuation mechanism of architectures made of CNTs. (paper)

  2. 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

  3. 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.

  4. 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.

  5. Method for producing carbon nanotubes

    Science.gov (United States)

    Phillips, Jonathan [Santa Fe, NM; Perry, William L [Jemez Springs, NM; Chen, Chun-Ku [Albuquerque, NM

    2006-02-14

    Method for producing carbon nanotubes. Carbon nanotubes were prepared using a low power, atmospheric pressure, microwave-generated plasma torch system. After generating carbon monoxide microwave plasma, a flow of carbon monoxide was directed first through a bed of metal particles/glass beads and then along the outer surface of a ceramic tube located in the plasma. As a flow of argon was introduced into the plasma through the ceramic tube, ropes of entangled carbon nanotubes, attached to the surface of the tube, were produced. Of these, longer ropes formed on the surface portion of the tube located in the center of the plasma. Transmission electron micrographs of individual nanotubes revealed that many were single-walled.

  6. Electronics with carbon nanotubes

    International Nuclear Information System (INIS)

    Avouris, P.

    2007-01-01

    From mobile phones and laptops to Xboxes and iPods, it is difficult to think of any aspect of modern life that has not been touched by developments in electronics, computing and communications over the last few decades. Many of these technological advances have arisen from our ability to create ever smaller electronic devices, in particular silicon-based field effect transistors (FETs), which has led to denser, faster and less power-hungry circuits. The problem is that this device miniaturization, or 'scaling', cannot continue forever. Fundamental scientific and technological limitations exist that will make it impossible to build better performing silicon devices below a certain size. This potential show-stopper has inspired a worldwide effort to develop alternative device technologies based on 1D materials or those that exploit the spin, as well as the charge, of electrons. One promising and, in principle, simpler approach is to maintain the operating concept of today's silicon-based FETs but to replace a key component of the device - the semiconducting silicon channel - with 1D nanostructures that have much more versatile electrical-transport properties. Among the different 1D materials that have been developed, those with the most desirable properties are 'single-walled' carbon nanotubes, which were first created in 1993 by Sumio Ijima at the NEC Fundamental Research Laboratory in Tsukuba, Japan, and by Donald Bethune of IBM's Almaden Research Center in California. These materials are hollow tubes made from rolled up sheets of carbon just one atom thick, otherwise known as graphene. In the March issue of Physics World, Phaedon Avouris discusses some of the many properties and applications of carbon nanotubes, which he describes as an 'engineer's dream' because of their exceptionally high strength and heat conduction. (U.K.)

  7. Underwater Acoustic Carbon Nanotube Thermophone

    Science.gov (United States)

    2016-09-23

    decreases rapidly as the distance from the conductor increases. Based on the rapid production of these temperature waves; the net effect is to produce a...fragile and are susceptible to disintegration especially if the nanotube fibers are touched or moved too quickly. A bare nanotube configuration also has...impedance (defined as the product of material density and sound speed) of the top shell 42 should match the radiation medium for higher efficiency

  8. Functionalization of Carbon Nanotubes

    Science.gov (United States)

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

    2009-01-01

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

  9. 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.

  10. Carbon Nanotube based Nanotechnolgy

    Science.gov (United States)

    Meyyappan, M.

    2000-10-01

    Carbon nanotube(CNT) was discovered in the early 1990s and is an off-spring of C60(the fullerene or buckyball). CNT, depending on chirality and diameter, can be metallic or semiconductor and thus allows formation of metal-semiconductor and semiconductor-semiconductor junctions. CNT exhibits extraordinary electrical and mechanical properties and offers remarkable potential for revolutionary applications in electronics devices, computing and data storage technology, sensors, composites, storage of hydrogen or lithium for battery development, nanoelectromechanical systems(NEMS), and as tip in scanning probe microscopy(SPM) for imaging and nanolithography. Thus the CNT synthesis, characterization and applications touch upon all disciplines of science and engineering. A common growth method now is based on CVD though surface catalysis is key to synthesis, in contrast to many CVD applications common in microelectronics. A plasma based variation is gaining some attention. This talk will provide an overview of CNT properties, growth methods, applications, and research challenges and opportunities ahead.

  11. Proposal of Carbon Nanotube Inductors

    National Research Council Canada - National Science Library

    Tsubaki, K; Nakajima, Y; Hanajiri, T; Yamaguchi, H

    2006-01-01

    The inductors made of carbon Nanotube (CNT) have been proposed. Though the fabrication of the proposed inductor is still challenging and has many problems, merits of the proposed inductor are following...

  12. Effect of Heat Drawing Process on Mechanical Properties of Dry-Jet Wet Spun Fiber of Linear Low Density Polyethylene/Carbon Nanotube Composites

    Directory of Open Access Journals (Sweden)

    Jong Won Kim

    2017-01-01

    Full Text Available Polyethylene is one of the most commonly used polymer materials. Even though linear low density polyethylene (LLDPE has better mechanical properties than other kinds of polyethylene, it is not used as a textile material because of its plastic behavior that is easy to break at the die during melt spinning. In this study, LLDPE fibers were successfully produced with a new approach using a dry-jet wet spinning and a heat drawing process. The fibers were filled with carbon nanotubes (CNTs to improve the strength and reduce plastic deformation. The crystallinity, degree of orientation, mechanical properties (strength to yield, strength to break, elongation at break, and initial modulus, electrical conductivity, and thermal properties of LLDPE fibers were studied. The results show that the addition of CNTs improved the tensile strength and the degree of crystallinity. The heat drawing process resulted in a significant increase in the tensile strength and the orientation of the CNTs and polymer chains. In addition, this study demonstrates that the heat drawing process effectively decreases the plastic deformation of LLDPE.

  13. Hybrid fibers made of molybdenum disulfide, reduced graphene oxide, and multi-walled carbon nanotubes for solid-state, flexible, asymmetric supercapacitors.

    Science.gov (United States)

    Sun, Gengzhi; Zhang, Xiao; Lin, Rongzhou; Yang, Jian; Zhang, Hua; Chen, Peng

    2015-04-07

    One of challenges existing in fiber-based supercapacitors is how to achieve high energy density without compromising their rate stability. Owing to their unique physical, electronic, and electrochemical properties, two-dimensional (2D) nanomaterials, e.g., molybdenum disulfide (MoS2 ) and graphene, have attracted increasing research interest and been utilized as electrode materials in energy-related applications. Herein, by incorporating MoS2 and reduced graphene oxide (rGO) nanosheets into a well-aligned multi-walled carbon nanotube (MWCNT) sheet followed by twisting, MoS2 -rGO/MWCNT and rGO/MWCNT fibers are fabricated, which can be used as the anode and cathode, respectively, for solid-state, flexible, asymmetric supercapacitors. This fiber-based asymmetric supercapacitor can operate in a wide potential window of 1.4 V with high Coulombic efficiency, good rate and cycling stability, and improved energy density. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. 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.)

  15. 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.

  16. 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....

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

    Science.gov (United States)

    Menchhofer, Paul A [Clinton, TN; Montgomery, Frederick C [Oak Ridge, TN; Baker, Frederick S [Oak Ridge, TN

    2011-11-08

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

  18. 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.

  19. Multiwalled carbon nanotubes coated fibers for solid-phase microextraction of polybrominated diphenyl ethers in water and milk samples before gas chromatography with electron-capture detection.

    Science.gov (United States)

    Wang, Jun-Xia; Jiang, Dong-Qing; Gu, Zhi-Yuan; Yan, Xiu-Ping

    2006-12-22

    Determination of polybrominated diphenyl ethers (PBDEs) in environmental samples has raised great concerns due to the widespread use of PBDEs and their potential risk to humans. Solid-phase microextraction (SPME) is a fast, simple, cost-effective, and green sample preparation technique and is widely used for environmental analysis, but reports on the application of SPME for determination of PBDEs are very limited, and only a few publications dealing with commercial SPME fibers are available for extraction of PBDEs. Herein, we report a novel SPME method using multiwalled carbon nanotubes (MWCNTs) as the SPME fiber coating for gas chromatography with electron-capture detection (GC-ECD) of PBDEs in environmental samples. The MWCNTs coating gave much higher enhancement factors (616-1756) than poly (5% dibenzene-95% dimethylsiloxane) coating (139-384) and activated carbon coating (193-423). Thirty-minute extraction of 10 mL of sample solution using the MWCNTs coated fiber for GC-ECD determination yielded the limits of detection of 3.6-8.6 ng L(-1) and exhibited good linearity of the calibration functions (r(2)>0.995). The precision (RSD%, n=4) for peak area and retention time at the 500 ng L(-1) level was 6.9-8.8% and 0.6-0.9%, respectively. The developed method was successfully applied for the analysis of real samples including local river water, wastewater, and milk samples. The recovery of the PBDEs at 500 ng L(-1) spiked in these samples ranged from 90 to 119%. No PBDEs were detected in the river water and skimmed milk samples, whereas in the wastewater sample, 134-215 ng L(-1) of PBDEs were found. The PBDEs were detected in all whole fat milk samples, ranging from 13 to 484 ng L(-1). In a semiskimmed milk sample, only BDE-47 was found at 21 ng L(-1).

  20. Multiwall carbon nanotube- zirconium oxide nanocomposite hollow fiber solid phase microextraction for determination of polyaromatic hydrocarbons in water, coffee and tea samples.

    Science.gov (United States)

    Yazdi, Mahnaz Nozohour; Yamini, Yadollah; Asiabi, Hamid

    2018-06-15

    The purpose of this study was to evaluate the application of hollow fiber solid-phase microextraction (HF-SPME) followed by HPLC-UV to determine the ultra-trace amounts of polycyclic aromatic hydrocarbons (PAHs) as model analytes in complex coffee and tea samples. HF-SPME can be effectively used as an alternative to the direct immersion SPME (DI-SPME) method in complex matrices. The DI-SPME method suffers from serious limitation in dirty and complicated matrices with low sample clean-up, while the HF-SPME method has high clean-up and selectivity due to the high porosity of hollow fiber that can pick out analyte from complicated matrices. As a hollow fiber sorbent, a novel multiwall carbon nanotube/zirconium oxide nanocomposite (MWCNT/ZrO 2 ) was fabricated. The excellent adsorption of PAHs on the sorbent was attributed to the dominant roles of π-π stacking interaction and hydrophobic interaction. Under the optimized extraction conditions, the wide linear range of 0.1-200 μg L -1 with coefficients of determination better than 0.998 and low detection limits of 0.033-0.16 μg L -1 with satisfactory precision (RSD tea samples were in the range of 92.0-106.0%. Compared to other methods, MWCNT/ZrO 2 hollow fiber solid phase microextraction demonstrated a good capability for determination of PAHs in complex coffee and tea samples. Copyright © 2018 Elsevier B.V. All rights reserved.

  1. Characterization of Reinforced Structural Composites with Carbon Nanotubes Grown Directly on the Fibers/Fabrics Using the PopTube Approach

    Data.gov (United States)

    National Aeronautics and Space Administration — An ideal candidate to accomplish the reinforcement of the matrix and interphase zone of FRPs is carbon nanotubes (CNTs), because of their superior mechanical...

  2. 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 ...

  3. Quantum transport in carbon nanotubes

    DEFF Research Database (Denmark)

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

    2015-01-01

    Carbon nanotubes are a versatile material in which many aspects of condensed matter physics come together. Recent discoveries, enabled by sophisticated fabrication, have uncovered new phenomena that completely change our understanding of transport in these devices, especially the role of the spin...... blockade. This can be exploited to read out spin and valley qubits, and to measure the decay of these states through coupling to nuclear spins and phonons. A second unique property of carbon nanotubes is that the combination of valley freedom and electron-electron interactions in one dimension strongly...... 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...

  4. Carbon Nanotube Based Molecular Electronics

    Science.gov (United States)

    Srivastava, Deepak; Saini, Subhash; Menon, Madhu

    1998-01-01

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

  5. Multiscale Modeling with Carbon Nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Maiti, A

    2006-02-21

    Technologically important nanomaterials come in all shapes and sizes. They can range from small molecules to complex composites and mixtures. Depending upon the spatial dimensions of the system and properties under investigation computer modeling of such materials can range from equilibrium and nonequilibrium Quantum Mechanics, to force-field-based Molecular Mechanics and kinetic Monte Carlo, to Mesoscale simulation of evolving morphology, to Finite-Element computation of physical properties. This brief review illustrates some of the above modeling techniques through a number of recent applications with carbon nanotubes: nano electromechanical sensors (NEMS), chemical sensors, metal-nanotube contacts, and polymer-nanotube composites.

  6. 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

  7. 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.

  8. Synthesis of carbon nanotubes bridging metal electrodes

    International Nuclear Information System (INIS)

    Kotlar, M.; Vojs, M.; Marton, M.; Vesel, M.; Redhammer, R.

    2012-01-01

    In our work we demonstrate growth of carbon nanotubes that can conductively bridge the metal electrodes. The role of different catalysts was examined. Interdigitated metal electrodes are made from copper and we are using bimetal Al/Ni as catalyst for growth of carbon nanotubes. We are using this catalyst composition for growth of the single-walled carbon nanotube network. (authors)

  9. Structural transformations of carbon chains inside nanotubes

    International Nuclear Information System (INIS)

    Warner, Jamie H.; Ruemmeli, Mark H.; Bachmatiuk, Alicja; Buechner, Bernd

    2010-01-01

    In situ aberration-corrected high-resolution transmission electron microscopy is used to examine the structural transformations of carbon chains that occur in the interior region of carbon nanotubes. We find electron-beam irradiation leads to the formation of two-dimensional carbon structures that are freely mobile inside the nanotube. The inner diameter of the nanotube influences the structural transformations of the carbon chains. As the diameter of the nanotube increases, electron-beam irradiation leads to curling of the chains and eventually the formation of closed looped structures. The closed looped structures evolve into spherical fullerenelike structures that exhibit translational motion inside the nanotubes and also coalesce to form larger nanotube structures. These results demonstrate the use of carbon nanotubes as test tubes for growing small carbon nanotubes within the interior by using only electron-beam irradiation at 80 kV.

  10. Carbon nanotube: the inside story.

    Science.gov (United States)

    Ando, Yoshinori

    2010-06-01

    Carbon nanotubes (CNTs) were serendipitously discovered as a byproduct of fullerenes by direct current (DC) arc discharge; and today this is the most-wanted material in the nanotechnology research. In this brief review, I begin with the history of the discovery of CNTs and focus on CNTs produced by arc discharge in hydrogen atmosphere, which is little explored outside my laboratory. DC arc discharge evaporation of pure graphite rod in pure hydrogen gas results in multi-walled carbon nanotubes (MWCNTs) of high crystallinity in the cathode deposit. As-grown MWCNTs have very narrow inner diameter. Raman spectra of these MWCNTs show high-intensity G-band, unusual high-frequency radial breathing mode at 570 cm(-1), and a new characteristic peak near 1850 cm(-1). Exciting carbon nanowires (CNWs), consisting of a linear carbon chain in the center of MWCNTs are also produced. Arc evaporation of graphite rod containing metal catalysts results in single-wall carbon nanotubes (SWCNTs) in the whole chamber like macroscopic webs. Two kinds of arc method have been developed to produce SWCNTs: Arc plasma jet (APJ) and Ferrum-Hydrogen (FH) arc methods. Some new purification methods for as-produced SWCNTs are reviewed. Finally, double-walled carbon nanotubes (DWCNTs) are also described.

  11. Photodetector based on carbon nanotubes

    Science.gov (United States)

    Pavlov, A.; Kitsyuk, E.; Ryazanov, R.; Timoshenkov, V.; Adamov, Y.

    2015-09-01

    Photodetector based on carbon nanotubes (CNT) was investigated. Sensors were done on quartz and silicon susbtrate. Samples of photodetectors sensors were produced by planar technology. This technology included deposition of first metal layer (Al), lithography for pads formation, etching, and formation of local catalyst area by inverse lithography. Vertically-aligned multi-wall carbon nanotubes were directly synthesized on substrate by PECVD method. I-V analysis and spectrum sensitivity of photodetector were investigated for 0.4 μm - 1.2 μm wavelength. Resistivity of CNT layers over temperature was detected in the range of -20°C to 100°C.

  12. CMOS Integrated Carbon Nanotube Sensor

    International Nuclear Information System (INIS)

    Perez, M. S.; Lerner, B.; Boselli, A.; Lamagna, A.; Obregon, P. D. Pareja; Julian, P. M.; Mandolesi, P. S.; Buffa, F. A.

    2009-01-01

    Recently carbon nanotubes (CNTs) have been gaining their importance as sensors for gases, temperature and chemicals. Advances in fabrication processes simplify the formation of CNT sensor on silicon substrate. We have integrated single wall carbon nanotubes (SWCNTs) with complementary metal oxide semiconductor process (CMOS) to produce a chip sensor system. The sensor prototype was designed and fabricated using a 0.30 um CMOS process. The main advantage is that the device has a voltage amplifier so the electrical measure can be taken and amplified inside the sensor. When the conductance of the SWCNTs varies in response to media changes, this is observed as a variation in the output tension accordingly.

  13. All carbon nanotubes are not created equal

    International Nuclear Information System (INIS)

    Geohegan, David B.; Puretzky, Alexander A.; Rouleau, Christopher M.

    2010-01-01

    This chapter presents the various factors that enter into consideration when choosing the source of carbon nanotubes for a specific application. Carbon nanotubes are giant molecules made of pure carbon. They have captured the imagination of the scientific community by the unique structure that provides superior physical, chemical, and electrical properties. However, a surprisingly wide disparity exists between the intrinsic properties determined under ideal conditions and the properties that carbon nanotubes exhibit in real world situations. The lack of uniformity in carbon nanotube properties is likely to be the main obstacle holding back the development of carbon nanotube applications. This tutorial addresses the nonuniformity of carbon nanotube properties from the synthesis standpoint. This synthesis-related nonuniformity is on top of the intrinsic chirality distribution that gives the ∼1:2 ratio of metallic to semiconducting nanotubes. From the standpoint of carbon bonding chemistry the variation in the quality and reproducibility of carbon nanotube materials is not unexpected. It is an intrinsic feature that is related to the metastability of carbon structures. The extent to which this effect is manifested in carbon nanotube formation is governed by the type and the kinetics of the carbon nanotube synthesis reaction. Addressing this variation is critical if nanotubes are to live up to the potential already demonstrated by their phenomenal physical properties.

  14. Synthesis of carbon nanotubes and nanotube forests on copper catalyst

    International Nuclear Information System (INIS)

    Kruszka, Bartosz; Terzyk, Artur P; Wiśniewski, Marek; Gauden, Piotr A; Szybowicz, Mirosław

    2014-01-01

    The growth of carbon nanotubes on bulk copper is studied. We show for the first time, that super growth chemical vapor deposition method can be successfully applied for preparation of nanotubes on copper catalyst, and the presence of hydrogen is necessary. Next, different methods of copper surface activation are studied, to improve catalyst efficiency. Among them, applied for the first time for copper catalyst in nanotubes synthesis, sulfuric acid activation is the most promising. Among tested samples the surface modified for 10 min is the most active, causing the growth of vertically aligned carbon nanotube forests. Obtained results have potential importance in application of nanotubes and copper in electronic chips and nanodevices. (paper)

  15. Carbon nanotubes and methods of making carbon nanotubes

    KAUST Repository

    Basset, Jean-Marie; Zhou, Lu; Saih, Youssef

    2017-01-01

    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

  16. 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.

  17. 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.

  18. Exposure to Carbon Nanotube Material: Assessment of Nanotube Cytotoxicity Using Human Keratinocyte Cells

    Science.gov (United States)

    Shvedova, Anna A.; Castranova, Vincent; Kisin, Elena R.; Schwegler-Berry, Diane; Murray, Ashley R.; Gandelsman, Vadim Z.; Maynard, Andrew; Baron, Paul

    2003-01-01

    Carbon nanotubes are new members of carbon allotropes similar to fullerenes and graphite. Because of their unique electrical, mechanical, and thermal properties, carbon nanotubes are important for novel applications in the electronics, aerospace, and computer industries. Exposure to graphite and carbon materials has been associated with increased incidence of skin diseases, such as carbon fiber dermatitis, hyperkeratosis, and naevi. We investigated adverse effects of single-wall carbon nanotubes (SWCNT) using a cell culture of immortalized human epidermal keratinocytes (HaCaT). After 18 h of exposure of HaCaT to SWCNT, oxidative stress and cellular toxicity were indicated by formation of free radicals, accumulation of peroxidative products, antioxidant depletion, and loss of cell viability. Exposure to SWCNT also resulted in ultrastructural and morphological changes in cultured skin cells. These data indicate that dermal exposure to unrefined SWCNT may lead to dermal toxicity due to accelerated oxidative stress in the skin of exposed workers.

  19. 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

  20. Carbon nanotube-chalcogenide composite

    Czech Academy of Sciences Publication Activity Database

    Stehlík, Š.; Orava, J.; Kohoutek, T.; Wágner, T.; Frumar, M.; Zima, Vítězslav; Hara, T.; Matsui, Y.; Ueda, K.; Pumera, M.

    2010-01-01

    Roč. 183, č. 1 (2010), s. 144-149 ISSN 0022-4596 R&D Projects: GA ČR GA203/08/0208 Institutional research plan: CEZ:AV0Z40500505 Keywords : carbon nanotubes * chalcogenide glasses * composites Subject RIV: CA - Inorganic Chemistry Impact factor: 2.261, year: 2010

  1. Polyurethane compounds having carbon nanotubes

    NARCIS (Netherlands)

    2010-01-01

    The invention relates to semi-crystalline polyurethane (PUR) compositions filled with carbon nanotubes (CNT) and having improved electrical properties, which can be obtained on the basis of water-based polyurethane/CNT mixtures. The invention further relates to a method for producing polyurethane

  2. Functionalized carbon nanotubes containing isocyanate groups

    International Nuclear Information System (INIS)

    Zhao Chungui; Ji Lijun; Liu Huiju; Hu Guangjun; Zhang Shimin; Yang Mingshu; Yang Zhenzhong

    2004-01-01

    Functionalized carbon nanotubes containing isocyanate groups can extend the nanotube chemistry, and may promote their many potential applications such as in polymer composites and coatings. This paper describes a facile method to prepare functionalized carbon nanotubes containing highly reactive isocyanate groups on its surface via the reaction between toluene 2,4-diisocyanate and carboxylated carbon nanotubes. Fourier-transformed infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) confirmed that reactive isocyanate groups were covalently attached to carbon nanotubes. The content of isocyanate groups were determined by chemical titration and thermogravimetric analysis (TGA)

  3. Hybrid Composites Based on Carbon Fiber/Carbon Nanofilament Reinforcement

    Directory of Open Access Journals (Sweden)

    Mehran Tehrani

    2014-05-01

    Full Text Available Carbon nanofilament and nanotubes (CNTs have shown promise for enhancing the mechanical properties of fiber-reinforced composites (FRPs and imparting multi-functionalities to them. While direct mixing of carbon nanofilaments with the polymer matrix in FRPs has several drawbacks, a high volume of uniform nanofilaments can be directly grown on fiber surfaces prior to composite fabrication. This study demonstrates the ability to create carbon nanofilaments on the surface of carbon fibers employing a synthesis method, graphitic structures by design (GSD, in which carbon structures are grown from fuel mixtures using nickel particles as the catalyst. The synthesis technique is proven feasible to grow nanofilament structures—from ethylene mixtures at 550 °C—on commercial polyacrylonitrile (PAN-based carbon fibers. Raman spectroscopy and electron microscopy were employed to characterize the surface-grown carbon species. For comparison purposes, a catalytic chemical vapor deposition (CCVD technique was also utilized to grow multiwall CNTs (MWCNTs on carbon fiber yarns. The mechanical characterization showed that composites using the GSD-grown carbon nanofilaments outperform those using the CCVD-grown CNTs in terms of stiffness and tensile strength. The results suggest that further optimization of the GSD growth time, patterning and thermal shield coating of the carbon fibers is required to fully materialize the potential benefits of the GSD technique.

  4. Manganese dioxide decoration of macroscopic carbon nanotube fibers: From high-performance liquid-based to all-solid-state supercapacitors

    Science.gov (United States)

    Pendashteh, Afshin; Senokos, Evgeny; Palma, Jesus; Anderson, Marc; Vilatela, Juan J.; Marcilla, Rebeca

    2017-12-01

    Supercapacitors capable of providing high voltage, energy and power density but yet light, low volume occupying, flexible and mechanically robust are highly interesting and demanded for portable applications. Herein, freestanding flexible hybrid electrodes based on MnO2 nanoparticles grown on macroscopic carbon nanotube fibers (CNTf-MnO2) were fabricated, without the need of any metallic current collector. The CNTf, a support with excellent electrical conductivity, mechanical stability, and appropriate pore structure, was homogeneously decorated with porous akhtenskite ɛ-MnO2 nanoparticles produced via electrodeposition in an optimized organic-aqueous mixture. Electrochemical properties of these decorated fibers were evaluated in different electrolytes including a neutral aqueous solution and a pure 1-butyl-3-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ionic liquid (PYR14TFSI). This comparison helps discriminate the various contributions to the total capacitance: (surface) Faradaic and non-Faradaic processes, improved wetting by aqueous electrolytes. Accordingly, symmetric supercapacitors with PYR14TFSI led to a high specific energy of 36 Wh· kgMnO2-1 (16 Wh·kg-1 including the weight of CNTf) and real specific power of 17 kW· kgMnO2-1 (7.5 kW kg-1) at 3.0 V with excellent cycling stability. Moreover, flexible all solid-state supercapacitors were fabricated using PYR14TFSI-based polymer electrolyte, exhibiting maximum energy density of 21 Wh·kg-1 and maximum power density of 8 kW kg-1 normalized by total active material.

  5. Application of carbon nanotubes flexible strain sensor in smart textiles

    Directory of Open Access Journals (Sweden)

    Qiong CHENG

    2017-10-01

    Full Text Available Smart textiles have not only the necessary functions of daily wear, but also the intelligence. The focus of the current textile materials research is the selection of flexible material. For flexible materials, carbon material is one of the ideal materials for preparing flexible strain gauges. The application of flexible strain sensor prepared by carbon nanotubes as a flexible material in smart textiles is the research content. The research status of carbon nanotubes flexible strain sensor is introduced from the aspects of the structure, properties and application. The characteristics and functions of flexible strain gages prepared with carbon nanotube fibers and carbon nanotube films as flexible materials are discussed in terms of selection, preparation method, performance test and application. At the same time, the advantages and disadvantages of the flexible strain sensor of carbon nanotubes are reviewed from the aspects of preparation difficulty, production cost and practical application effect. High sensitivity with high strain will be a key research direction for carbon nanotube flexible strain sensors.

  6. Progress Toward Sequestering Carbon Nanotubes in PmPV

    Science.gov (United States)

    Bley, Richard A.

    2009-01-01

    Sequestration of single-walled carbon nanotubes (SWNTs) in molecules of poly(m-phenylenevinylene-co-2,5-diocty-loxy-p-phenylenevinylene) [PmPV] is a candidate means of promoting dissolution of single-walled carbon nanotubes (SWNTs) into epoxies for making strong, lightweight epoxy-matrix/carbon-fiber composite materials. Bare SWNTs cannot be incorporated because they are not soluble in epoxies. In the present approach, one exploits the tendency of PmPV molecules to wrap themselves around SWNTs without chemically bonding to them.

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

    Science.gov (United States)

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

    2015-01-01

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

  8. Theoretical properties of carbon nanotubes

    International Nuclear Information System (INIS)

    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 that these methods provide efficient and robust ways of performing linear-scaling calculations, either grand canonically (at a fixed chemical potential) or canonically (at a fixed electron count). (author)

  9. In silico assembly and nanomechanical characterization of carbon nanotube buckypaper

    International Nuclear Information System (INIS)

    Cranford, Steven W; Buehler, Markus J

    2010-01-01

    Carbon nanotube sheets or films, also known as 'buckypaper', have been proposed for use in actuating, structural and filtration systems, based in part on their unique and robust mechanical properties. Computational modeling of such a fibrous nanostructure is hindered by both the random arrangement of the constituent elements as well as the time- and length-scales accessible to atomistic level molecular dynamics modeling. Here we present a novel in silico assembly procedure based on a coarse-grain model of carbon nanotubes, used to attain a representative mesoscopic buckypaper model that circumvents the need for probabilistic approaches. By variation in assembly parameters, including the initial nanotube density and ratio of nanotube type (single- and double-walled), the porosity of the resulting buckypaper can be varied threefold, from approximately 0.3 to 0.9. Further, through simulation of nanoindentation, the Young's modulus is shown to be tunable through manipulation of nanotube type and density over a range of approximately 0.2-3.1 GPa, in good agreement with experimental findings of the modulus of assembled carbon nanotube films. In addition to carbon nanotubes, the coarse-grain model and assembly process can be adapted for other fibrous nanostructures such as electrospun polymeric composites, high performance nonwoven ballistic materials, or fibrous protein aggregates, facilitating the development and characterization of novel nanomaterials and composites as well as the analysis of biological materials such as protein fiber films and bulk structures.

  10. Preparation of thick silica coatings on carbon fibers with fine-structured silica nanotubes induced by a self-assembly process

    Directory of Open Access Journals (Sweden)

    Benjamin Baumgärtner

    2017-05-01

    Full Text Available A facile method to coat carbon fibers with a silica shell is presented in this work. By immobilizing linear polyamines on the carbon fiber surface, the high catalytic activity of polyamines in the sol–gel-processing of silica precursors is used to deposit a silica coating directly on the fiber’s surface. The surface localization of the catalyst is achieved either by attaching short-chain polyamines (e.g., tetraethylenepentamine via covalent bonds to the carbon fiber surface or by depositing long-chain polyamines (e.g., linear poly(ethylenimine on the carbon fiber by weak non-covalent bonding. The long-chain polyamine self-assembles onto the carbon fiber substrate in the form of nanoscopic crystallites, which serve as a template for the subsequent silica deposition. The silicification at close to neutral pH is spatially restricted to the localized polyamine and consequently to the fiber surface. In case of the linear poly(ethylenimine, silica shells of several micrometers in thickness can be obtained and their morphology is easily controlled by a considerable number of synthesis parameters. A unique feature is the hierarchical biomimetic structure of the silica coating which surrounds the embedded carbon fiber by fibrillar and interconnected silica fine-structures. The high surface area of the nanostructured composite fiber may be exploited for catalytic applications and adsorption purposes.

  11. Nitrotyrosine adsorption on carbon nanotube: a density functional theory study

    Science.gov (United States)

    Majidi, R.; Karami, A. R.

    2014-05-01

    We have studied the effect of nitrotyrosine on electronic properties of different single-wall carbon nanotubes by density functional theory. Optimal adsorption configurations of nitrotyrosine adsorbed on carbon nanotube have been determined by calculation of adsorption energy. Adsorption energies indicate that nitrotyrosine is chemisorbed on carbon nanotubes. It is found that the nitrotyrosine adsorption modifies the electronic properties of the semiconducting carbon nanotubes significantly and these nanotubes become n-type semiconductors, while the effect of nitrotyrosine on metallic carbon nanotubes is not considerable and these nanotubes remain metallic. Results clarify sensitivity of carbon nanotubes to nitrotyrosine adsorption and suggest the possibility of using carbon nanotubes as biosensor for nitrotyrosine detection.

  12. N-doped carbon nanotubes-reinforced hollow fiber solid-phase microextraction coupled with high performance liquid chromatography for the determination of phytohormones in tomatoes.

    Science.gov (United States)

    Han, Xiao-Fei; Chen, Juan; Shi, Yan-Ping

    2018-08-01

    A N-doped carbon nanotubes-reinforced hollow fiber solid-phase microextraction (N-doped CNTs-HF-SPME) method was developed for determination of two naphthalene-derived phytohormones, 1-naphthalene acetic acid (NAA) and 2-naphthoxyacetic acid (2-NOA), at trace levels in tomatoes. N-doped CNTs were dispersed in ultrapure water with the assistance of surfactant, and then immobilized into the pores of hollow fiber by capillary forces and sonification. The resultant N-doped CNTs-HF was wetted with 1-octanol, subsequently immersed into the tomato samples to extract the target analytes under a magnetic stirring, and then desorbed with methanol by sonication prior to chromatographic analysis. Compared with CNTs, the surface hydrophilicity of N-doped CNTs was improved owing to the doping of nitrogen atoms, and a uniform dispersion was formed, thus greatly simplifying the preparation process and reducing waste of materials. In addition, N-doped CNTs-HF exhibits a more effective extraction performance for NAA and 2-NOA on account of the introduction of Lewis-basic nitrogen. It is worth to mention that owing to the clean-up function of HF, there are not any complicated sample pretreatment procedures prior to the microextraction. To achieve the highest extraction efficiency, important microextraction parameters including the length and the concentration level of N-doped CNTs in surfactant solution, extraction time, desorption conditions such as the type and volume of solvents, pH value, stirring rate and volume of the donor phase were thoroughly investigated and optimized. Under the optimal conditions, the method showed 165- and 123-fold enrichment factors of NAA and 2-NOA, good inter-fiber repeatability and batch-to-batch reproducibility, good linearity with correlation coefficients higher than 0.9990, low limits of detection and quantification (at ng g -1 levels), and satisfactory recoveries in the range of 83.10-108.32% at three spiked levels. The proposed method taking

  13. Vertically aligned carbon nanotube field-effect transistors

    KAUST Repository

    Li, Jingqi; Zhao, Chao; Wang, Qingxiao; Zhang, Qiang; Wang, Zhihong; Zhang, Xixiang; Abutaha, Anas I.; Alshareef, Husam N.

    2012-01-01

    Vertically aligned carbon nanotube field-effect transistors (CNTFETs) have been developed using pure semiconducting carbon nanotubes. The source and drain were vertically stacked, separated by a dielectric, and the carbon nanotubes were placed

  14. Synthesis of single and multi-shell carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Lambert, J M [Groupe de Dynamique des Phases Condensees, Univ. de Montpellier 2, 34 Montpellier (France); Ajayan, P M [Lab. de Physique des Solides, Univ. Paris-Sud, 91 Orsay (France); Bernier, P [Groupe de Dynamique des Phases Condensees, Univ. de Montpellier 2, 34 Montpellier (France)

    1995-03-15

    We report here interesting growth morphologies produced during the electric arc-discharge between a graphite cathode and different composite metal-graphite anodes: when the metal is pure cobalt powder, we obtain, under certain conditions of pressure and cobalt content in the electrode, many single-shell carbon nanotubes of 1-2 nm diameter which appear in the soot, webs, threads (in the reactor chamber) and also on a collaret that forms around the conventional deposit containing multi-shell nanotubes. When the metal is pure manganese powder, we obtain multi-layer hollow carbon fibers in the soot similar to the carbon fibers grown by catalytic chemical vapor deposition. Furthermore, many fibers have a good portion of the length filled with metal. We present here high-resolution transmission electron microscopy images of these structures. (orig.)

  15. Torsional carbon nanotube artificial muscles.

    Science.gov (United States)

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

    2011-10-28

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

  16. 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.

  17. EB treatment of carbon nanotube-reinforced polymer composites

    International Nuclear Information System (INIS)

    Szebenyi, G.; Romhany, G.; Czvikovszky, T.; Vajna, B.

    2011-01-01

    Complete text of publication follows. A small amount - less than 0.5% - carbon nanotube reinforcement may improve significantly the mechanical properties of epoxy based composite materials. The basic technical problem is on one side the dispersion of the nanotubes into the viscous matrix resin. Namely the fine, powder-like - less than 100 nanometer diameter - nanotubes are prone to form aggregates. On the other side, the good connection between the nanofiber and matrix, - which is determining the success of the reinforcement, - requires some efficient adhesion promoting treatment. After an elaborate masterbatch mixing technology we applied Electron Beam treatment of epoxy-matrix polymer composites containing carbon nanotubes in presence of vinylester resins. The Raman spectra of vinylester-epoxy mixtures treated by an 8 MeV EB showed the advantage of the electron treatment. Even in the case of partially immiscible epoxy and vinylester resins, the anchorage of carbon nanotubes reflects improvement if a reasonable 25 kGy EB dose is applied. Atomic Force Microscopy as well as mechanical tests on flexural and impact properties confirm the benefits of EB treatment. Simultaneous application of multiwall carbon nanotubes and 'conventional' carbon fibers as reinforcement in vinylester modified epoxies results in new types of hybrid nanocomposites as engineering materials. The bending- and interlaminar properties of such hybrid systems showed the beneficial effect of the EB treatment. Acknowledgement: This work has been supported by the New Hungary Development Plan (Project ID: TAMOP-4.2.1/B-09/1/KMR-2010-0002).

  18. The Preparation of Carbon Nanotube/MnO2 Composite Fiber and Its Application to Flexible Micro-Supercapacitor

    Directory of Open Access Journals (Sweden)

    Li Li

    2013-01-01

    Full Text Available In recent years, flexible electronic devices pursued for potential applications. The design and the fabrication of a novel flexible nanoarchitecture by coating electrical conductive MWCNT fiber with ultrathin films of MnO2 to achieve high specific capacitance, for micro-supercapacitors electrode applications, are demonstrated here. The MWCNT/MnO2 composite fiber electrode was prepared by the electrochemical deposition which was carried out through using two different methods: cyclic voltammetry and potentiostatic methods. The cyclic voltammetry method can get “crumpled paper ball” morphology MnO2 which has bigger specific capacitances than that achieved by potentiostatic method. The flexible micro-supercapacitor was fabricated by twisting two aligned MWCNT fibers and showed an area specific capacitance of 2.43 mF/cm2. The flexible micro-supercapacitors also enable promising applications in various fields.

  19. Carbon nanotubes for biological and biomedical applications

    International Nuclear Information System (INIS)

    Yang Wenrong; Thordarson, Pall; Gooding, J Justin; Ringer, Simon P; Braet, Filip

    2007-01-01

    Ever since the discovery of carbon nanotubes, researchers have been exploring their potential in biological and biomedical applications. The recent expansion and availability of chemical modification and bio-functionalization methods have made it possible to generate a new class of bioactive carbon nanotubes which are conjugated with proteins, carbohydrates, or nucleic acids. The modification of a carbon nanotube on a molecular level using biological molecules is essentially an example of the 'bottom-up' fabrication principle of bionanotechnology. The availability of these biomodified carbon nanotube constructs opens up an entire new and exciting research direction in the field of chemical biology, finally aiming to target and to alter the cell's behaviour at the subcellular or molecular level. This review covers the latest advances of bio-functionalized carbon nanotubes with an emphasis on the development of functional biological nano-interfaces. Topics that are discussed herewith include methods for biomodification of carbon nanotubes, the development of hybrid systems of carbon nanotubes and biomolecules for bioelectronics, and carbon nanotubes as transporters for a specific delivery of peptides and/or genetic material to cells. All of these current research topics aim at translating these biotechnology modified nanotubes into potential novel therapeutic approaches. (topical review)

  20. Use of Carbon Nano-Fiber Foams as Strain Gauges to Detect Crack Propagation

    Science.gov (United States)

    2015-06-01

    capacitors [18]. Another example are recent attempts to use carbon fibers and carbon nanotubes to develop sensor devices. Sida Luo created aligned... Sida Luo, “Structure-property-processing relationships of single-wall carbon nanotube thin film piezoresistive sensors,” SciVerse ScienceDirect, pp

  1. Mechanics of filled carbon nanotubes

    KAUST Repository

    Monteiro, A.O.; Cachim, P.B.; Da Costa, Pedro M. F. J.

    2014-01-01

    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. 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.

  3. All carbon coaxial supercapacitors based on hollow carbon nanotube sleeve structure

    International Nuclear Information System (INIS)

    Zang, Xiaobei; Xu, Ruiqiao; Zhang, Yangyang; Zhang, Li; Wei, Jinquan; Wang, Kunlin; Zhu, Hongwei; Li, Xinming

    2015-01-01

    All carbon coaxial supercapacitors based on hollow carbon nanotube (CNT) sleeve structure are assembled and tested. The key advantage of the structure is that the inner core electrode is variable from CNT sleeve sponges, to CNT fibers, reduced graphene oxide fibers, and graphene woven fabrics. By changing core electrodes from sleeve sponges to CNT fibers, the electrochemical performance has been significantly enhanced. The capacitance based on sleeve sponge + CNT fiber double the capacitances of double-sleeve sponge supercapacitors thanks to reduction of the series and internal resistances. Besides, the coaxial sleeve structure possesses many other features, including high rate capacitance, long cycle life, and good flexibility. (paper)

  4. Discovery of carbon nanotubes. Sara ni carbon nanotube e

    Energy Technology Data Exchange (ETDEWEB)

    Iijima, S

    1994-01-20

    This paper describes the following matters on carbon nanotubes (CNt): CNt is discovered in carbon deposits generated in the tip of a negative electrode during DC arc discharge between carbon electrodes. CNt has a construction in which cylinders made of normally several layers are superposed, based on cylindrical crystals in a single layer with six-member rings of carbon atoms laid out. Spiral arrangement of carbon six-member rings has been discovered in the single-layered crystals. Five-member rings exist in a location where the CNt tip is closed, and seven-member rings in a location where the CNt presents a saddle-like curve, without exceptions. It is introduced theoretically that the electronic structure of the single-layered CNt depends on the cylinder diameter and spiral pitch. Replacing part of the carbon negative electrode with iron, and vaporizing iron and carbon simultaneously through arc discharge can result in a single-layered CNt with a diameter of 1 nm. Heating the CNt deposited with metallic lead in an oxygen atmosphere can form CNt containing lead compounds. 19 refs., 9 figs.

  5. Chemically modified carbon fibers and their applications

    International Nuclear Information System (INIS)

    Ermolenko, I.N.; Lyubliner, I.P.; Gulko, N.V.

    1990-01-01

    This book gives a comprehensive review about chemically modified carbon fibers (e.g. by incorporation of other elements) and is structured as follows: 1. Types of carbon fibers, 2. Structure of carbon fibers, 3. Properties of carbon fibers, 4. The cellulose carbonization process, 5. Formation of element-carbon fiber materials, 6. Surface modification of carbon fibers, and 7. Applications of carbon fibers (e.g. adsorbents, catalysts, constituents of composites). (MM)

  6. Application of carbon nanotubes modified with a Keggin polyoxometalate as a new sorbent for the hollow-fiber micro-solid-phase extraction of trace naproxen in hair samples with fluorescence spectrophotometry using factorial experimental design.

    Science.gov (United States)

    Naddaf, Ezzat; Ebrahimi, Mahmoud; Es'haghi, Zarrin; Bamoharram, Fatemeh Farrash

    2015-07-01

    A sensitive technique to determinate naproxen in hair samples was developed using hollow-fiber micro-solid-phase combined with fluorescence spectrophotometry. The incorporation of multi-walled carbon nanotubes modified with a Keggin polyoxometalate into a silica matrix prepared by the sol-gel method was reported. In this research, the Keggin carbon nanotubes /silica composite was used in the pores and lumen of a hollow fiber as the hollow-fiber micro-solid-phase extraction device. The device was used for the microextraction of the analyte from hair and water samples under the optimized conditions. An orthogonal array experimental design with an OA24 (4(6) ) matrix was employed to optimize the conditions. The effect of six factors influencing the extraction efficiency was investigated: pH, salt, volume of donor and desorption phase, extraction and desorption time. The effect of each factor was estimated using individual contributions as response functions in the screening process. Analysis of variance was employed for estimating the main significant factors and their contributions in the extraction. Calibration curve plot displayed linearity over a range of 0.2-10 ng/mL with detection limits of 0.072 and 0.08 ng/mL for hair and aqueous samples, respectively. The relative recoveries in the hair and aqueous matrices ranged from 103-95%. The relative standard deviation for fiber-to-fiber repeatability was 3.9%. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Interaction of multiwalled carbon nanotube produces structural ...

    African Journals Online (AJOL)

    Abstract. Multiwalled carbon nanotube (MWCNT) has been found to produce structural changes in Calf Thymus-DNA (CT-DNA). The interaction or binding of the multi-walled carbon nanotubes (MWCNT) was investigated in order to discover if it brings about any significant changes of the DNA double helix using CD spectra ...

  8. Method for the preparation of carbon fiber from polyolefin fiber precursor, and carbon fibers made thereby

    Science.gov (United States)

    Naskar, Amit Kumar; Hunt, Marcus Andrew; Saito, Tomonori

    2015-08-04

    Methods for the preparation of carbon fiber from polyolefin fiber precursor, wherein the polyolefin fiber precursor is partially sulfonated and then carbonized to produce carbon fiber. Methods for producing hollow carbon fibers, wherein the hollow core is circular- or complex-shaped, are also described. Methods for producing carbon fibers possessing a circular- or complex-shaped outer surface, which may be solid or hollow, are also described.

  9. Nano-engineered composites: interlayer carbon nanotubes effect

    Energy Technology Data Exchange (ETDEWEB)

    Carley, Glaucio, E-mail: carleyone@hotmail.com [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil); Geraldo, Viviany; Oliveira, Sergio de [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Fisica; Avila, Antonio Ferreira [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Fisica

    2013-11-01

    The concept of carbon nanotube interlayer was successfully introduced to carbon fiber/epoxy composites. This new hybrid laminated composites was characterized by Raman spectroscopy, X-ray diffraction, scanning electron microscopy and tensile tests. An increase on peak stress close to 85% was witnessed when CNTs interlayer with 206.30 mg was placed to carbon fiber/epoxy laminates. The failure mechanisms are associated to CNTs distribution between and around carbon fibers. These CNTs are also responsible for crack bridging formation and the increase on peak stress. Initial stiffness is strongly affected by the CNT interlayer, however, changes on stiffness is associated to changes on nano/micro-structure due to damage. Three different behaviors can be described, i.e. for interlayers with Almost-Equal-To 60 mg of CNT the failure mode is based on cracks between and around carbon fibers, while for interlayers with CNT contents between 136 mg and 185 mg cracks were spotted on fibers and inside the CNT/matrix mix. Finally, the third failure mechanism is based on carbon fiber breakage, as a strong interface between CNT/matrix mix and carbon fibers is observed. (author)

  10. Nano-engineered composites: interlayer carbon nanotubes effect

    International Nuclear Information System (INIS)

    Carley, Glaucio; Geraldo, Viviany; Oliveira, Sergio de; Avila, Antonio Ferreira

    2013-01-01

    The concept of carbon nanotube interlayer was successfully introduced to carbon fiber/epoxy composites. This new hybrid laminated composites was characterized by Raman spectroscopy, X-ray diffraction, scanning electron microscopy and tensile tests. An increase on peak stress close to 85% was witnessed when CNTs interlayer with 206.30 mg was placed to carbon fiber/epoxy laminates. The failure mechanisms are associated to CNTs distribution between and around carbon fibers. These CNTs are also responsible for crack bridging formation and the increase on peak stress. Initial stiffness is strongly affected by the CNT interlayer, however, changes on stiffness is associated to changes on nano/micro-structure due to damage. Three different behaviors can be described, i.e. for interlayers with ≈ 60 mg of CNT the failure mode is based on cracks between and around carbon fibers, while for interlayers with CNT contents between 136 mg and 185 mg cracks were spotted on fibers and inside the CNT/matrix mix. Finally, the third failure mechanism is based on carbon fiber breakage, as a strong interface between CNT/matrix mix and carbon fibers is observed. (author)

  11. Study of novel carbon fiber composite used exfoliated carbon fibers

    Energy Technology Data Exchange (ETDEWEB)

    Toyoda, Masahiro [Oita Univ., 700 Dannoharu, Oita 870-1192 (Japan)], E-mail: toyoda22@cc.oita-u.ac.jp; Kohara, Ryotaro; Tsumura, Tomoki [Oita Univ., 700 Dannoharu, Oita 870-1192 (Japan); Mutoh, Hiroyuki; Sakai, Mototsugu [Toyohashi Univ. of Tech., Toyohashi 441-8580 (Japan)

    2009-04-15

    One of the applications for carbon nanotubes (CNTs), CNT composite has been studied to reinforce of polymer. However, CNTs have not shown enough reinforced effect, because of poor dispersibility of itself and low purification. These characteristics are connected with the lowering mechanical strength in CNT's reinforced polymer composite. On the other hand, exfoliated carbon fibers (ExCFs) prepared through electrochemical processing were found to have unique morphology such as nanometer or sub-micrometer sized fibrils and well dispersibility. Fabrication of composite using its ExCFs was investigated. ExCFs changed in nanometer-sized fibrils by using ultrasonication and CNTs dispersed by using ultrasonication were compounded with polymethyl methacrylate (PMMA) in situ process through polymerization, and then their mechanical properties were examined. Flexural strength and elasticity of PMMA composite reinforced by ExCFs increased 166 and 171% respectively at addition of only 2.0 wt.% comparison with bulk PMMA. There was no significant aggregation in fracture surface, and homogeneous dispersion of ExCFs throughout the PMMA matrix was recognized. It was better than that of PMMA composite reinforced by CNTs. Homogeneous dispersion might be strongly related to mechanical properties. ExCFs might be expected to be applied to nano-composite instead of CNTs.

  12. Liquid surface model for carbon nanotube energetics

    DEFF Research Database (Denmark)

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

    2008-01-01

    an important insight in the energetics and stability of nanotubes of different chirality and might be important for the understanding of nanotube growth process. For the computations we use empirical Brenner and Tersoff potentials and discuss their applicability to the study of carbon nanotubes. From......In the present paper we developed a model for calculating the energy of single-wall carbon nanotubes of arbitrary chirality. This model, which we call as the liquid surface model, predicts the energy of a nanotube with relative error less than 1% once its chirality and the total number of atoms...... 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. Carbon Nanotube Supercapacitors

    OpenAIRE

    Lu, Wen; Dai, Liming

    2010-01-01

    In summary, CNTs have been explored as a new type of electrode materials for supercapacitors. Both randomly entangled and highly aligned CNTs have been investigated. The former is relatively easier to fabricate while the latter has a better capacitor performance. Combining the unique properties of CNTs with the high surface area of activated carbons or the additional pseduocapacitance of redox materials (electroactive polymers and metal oxides), high-capacitance and high-rate nanocomposites a...

  14. Optical properties of carbon nanotubes

    Science.gov (United States)

    Chen, Gugang

    This thesis addresses the optical properties of novel carbon filamentary nanomaterials: single-walled carbon nanotubes (SWNTs), double-walled carbon nanotubes (DWNTs), and SWNTs with interior C60 molecules ("peapods"). Optical reflectance spectra of bundled SWNTs are discussed in terms of their electronic energy band structure. An Effective Medium Model for a composite material was found to provide a reasonable description of the spectra. Furthermore, we have learned from optical absorption studies of DWNTs and C60-peapods that the host tube and the encapsulant interact weakly; small shifts in interband absorption structure were observed. Resonant Raman scattering studies on SWNTs synthesized via the HiPCO process show that the "zone-folding" approximation for phonons and electrons works reasonably well, even for small diameter (d effect, rather than the vdW interaction. Finally, we studied the chemical doping of DWNTs, where the dopant (Br anions) is chemically bound to the outside of the outer tube. The doped DWNT system is a model for a cylindrical molecular capacitor. We found experimentally that 90% of the positive charge resides on the outer tube, so that most of electric field on the inner tube is screened, i.e., we have observed a molecular Faraday cage effect. A self-consistent theoretical model in the tight-binding approximation with a classical electrostatic energy term is in good agreement with our experimental results.

  15. Coated carbon nanotube array electrodes

    Science.gov (United States)

    Ren, Zhifeng [Newton, MA; Wen, Jian [Newton, MA; Chen, Jinghua [Chestnut Hill, MA; Huang, Zhongping [Belmont, MA; Wang, Dezhi [Wellesley, MA

    2008-10-28

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

  16. Structural properties of water around uncharged and charged carbon nanotubes

    International Nuclear Information System (INIS)

    Dezfoli, Amir Reza Ansari; Mehrabian, Mozaffar Ali; Rafsanjani, Hassan Hashemipour

    2013-01-01

    Studying the structural properties of water molecules around the carbon nanotubes is very important in a wide variety of carbon nanotubes applications. We studied the number of hydrogen bonds, oxygen and hydrogen density distributions, and water orientation around carbon nanotubes. The water density distribution for all carbon nanotubes was observed to have the same feature. In water-carbon nanotubes interface, a high-density region of water molecules exists around carbon nanotubes. The results reveal that the water orientation around carbon nanotubes is roughly dependent on carbon nanotubes surface charge. The water molecules in close distances to carbon nanotubes were found to make an HOH plane nearly perpendicular to the water-carbon nanotubes interface for carbon nanotubes with negative surface charge. For uncharged carbon nanotubes and carbon nanotubes with positive surface charge, the HOH plane was in tangential orientation with water-carbon nanotubes interface. There was also a significant reduction in hydrogen bond of water region around carbon nanotubes as compared with hydrogen bond in bulk water. This reduction was very obvious for carbon nanotubes with positive surface charge. In addition, the calculation of dynamic properties of water molecules in water-CNT interface revealed that there is a direct relation between the number of Hbonds and self-diffusion coefficient of water molecules

  17. Optical Study of Liquid Crystal Doped with Multiwalled Carbon Nanotube

    Science.gov (United States)

    Gharde, Rita A.; Thakare, Sangeeta Y.

    2014-11-01

    Liquid crystalline materials have been useful for display devices i.e watches, calculators, automobile dashboards, televisions, multi media projectors etc. as well as in electro tunable lasers, optical fibers and lenses. Carbon nanotube is chosen as the main experimental factor in this study as it has been observed that Carbon Nano Tube influence the existing properties of liquid crystal host and with the doping of CNT can enhance1 the properties of LC. The combination of carbon nanotube (CNT) and liquid crystal (LC) materials show considerable interest in the scientific community due to unique physical properties of CNT in liquid crystal. Dispersion of CNTs in LCs can provide us a cheap, simple, versatile and effective means of controlling nanotube orientation on macroscopic scale with no restrictions on nanotube type. LCs have the long range orientational order rendering them to be anisotropic phases. If CNTs can be well dispersed in LC matrix, they will align with their long axes along the LC director to minimize distortions of the LC director field and the free energy. In this paper, we doped liquid crystal (Cholesteryl Nonanoate) by a small amount of multiwall carbon nanotube 0.05% and 0.1% wt. We found that by adding carbon nanotube to liquid crystals the melting point of the mixture is decreased but TNI is increased. It has been also observed that with incereas in concentration of carbon nanotube into liquid crystal shows conciderable effect on LC. The prepared samples were characterized using various techniques to study structural, thermal and optical properties i.e PMS, FPSS, UV-Vis spectroscopy, FT-IR measurements, and DTA.

  18. Simultaneous quantification of arginine, alanine, methionine and cysteine amino acids in supplements using a novel bioelectro-nanosensor based on CdSe quantum dot/modified carbon nanotube hollow fiber pencil graphite electrode via Taguchi method.

    Science.gov (United States)

    Hooshmand, Sara; Es'haghi, Zarrin

    2017-11-30

    A number of four amino acids have been simultaneously determined at CdSe quantum dot-modified/multi-walled carbon nanotube hollow fiber pencil graphite electrode in different bodybuilding supplements. CdSe quantum dots were synthesized and applied to construct a modified carbon nanotube hollow fiber pencil graphite electrode. FT-IR, TEM, XRD and EDAX methods were applied for characterization of the synthesized CdSe QDs. The electro-oxidation of arginine (Arg), alanine (Ala), methionine (Met) and cysteine (Cys) at the surface of the modified electrode was studied. Then the Taguchi's method was applied using MINITAB 17 software to find out the optimum conditions for the amino acids determination. Under the optimized conditions, the differential pulse (DP) voltammetric peak currents of Arg, Ala, Met and Cys increased linearly with their concentrations in the ranges of 0.287-33670μM and detection limits of 0.081, 0.158, 0.094 and 0.116μM were obtained for them, respectively. Satisfactory results were achieved for calibration and validation sets. The prepared modified electrode represents a very good resolution between the voltammetric peaks of the four amino acids which makes it suitable for the detection of each in presence of others in real samples. Copyright © 2017. Published by Elsevier B.V.

  19. Review of carbon nanotube nanoelectronics and macroelectronics

    International Nuclear Information System (INIS)

    Che, Yuchi; Chen, Haitian; Gui, Hui; Liu, Jia; Liu, Bilu; Zhou, Chongwu

    2014-01-01

    Carbon nanotubes have the potential to spur future development in electronics due to their unequalled electrical properties. In this article, we present a review on carbon nanotube-based circuits in terms of their electrical performance in two major directions: nanoelectronics and macroelectronics. In the nanoelectronics direction, we direct our discussion to the performance of aligned carbon nanotubes for digital circuits and circuits designed for radio-frequency applications. In the macroelectronics direction, we focus our attention on the performance of thin films of carbon nanotube random networks in digital circuits, display applications, and printed electronics. In the last part, we discuss the existing challenges and future directions of nanotube-based nano- and microelectronics. (invited review)

  20. Effect of beam expansion loss in a carbon nanotube-doped PVA film on passively mode-locked erbium-doped fiber lasers with different feedback ratios

    International Nuclear Information System (INIS)

    Cheng, Kuang-Nan; Chi, Yu-Chieh; Cheng, Chih-Hsien; Lin, Yung-Hsiang; Lo, Jui-Yung; Lin, Gong-Ru

    2014-01-01

    The effect of beam expansion induced divergent loss in a single-wall carbon nanotube (SWCNT) doped polyvinyl alcohol (PVA) based ultrafast saturable absorber (SA) film thickness on the passive mode-locking (PML) performances of erbium-doped fiber lasers are demonstrated. The variation on the PML pulsewidth of the EDFL is discussed by changing the SWCNT-PVA SA film thicknesses, together with adjusting the pumping power and the intra-cavity feedback ratio. An almost 6 dB increment of divergent loss when enlarging the SWCNT-PVA based SA film thickness from 30–130 µm is observed. When shrinking the SA thickness to 30 µm at the largest pumping power of 52.5 mW, the optical spectrum red-shifts to 1558.8 nm with its 3 dB spectral linewidth broadening up to 2.7 nm, while the pulse has already entered the soliton regime with multi-order Kelly sidebands aside the spectral shoulder. The soliton pulsewidth is as short as 790 fs, which is much shorter than those obtained with other thicker SWCNT doped PVA polymer film based SAs; therefore, the peak power from the output of the PML-EDFL is significantly enlarged accompanied by a completely suppressed residual continuous-wave level to achieve the largest on/off extinction ratio. The main mechanism of pulse shortening with reducing thickness of SWCNT doped PVA polymer film based SA is attributed to the limited beam expansion as well as the enlarged modulation depth, which results in shortened soliton pulsewidth with a clean dc background, and broadened spectrum with enriched Kelly sidebands. The increase of total SWCNT amount in the thicker SA inevitably causes a higher linear absorption; hence, the mode-locking threshold also rises accordingly. By enlarging pumping power from 38.5–52.5 mW, the highest ascent on pulse extinction of up to 32 dB is observed among all kinds of feedback conditions. Nevertheless, the enlargement on the extinction slightly decays with increasing the feedback ratio from 30–90

  1. Structure of Carbon Nanotube-dendrimer composite

    OpenAIRE

    Vasumathi, V.; Pramanik, Debabrata; Sood, A. K.; Maiti, Prabal K

    2012-01-01

    Using all atomistic molecular dynamics (MD) simulations we report the microscopic picture of the nanotube-dendrimer complex for PAMAM dendrimer of generation 2 to 4 and carbon nanotube of chirality (6,5). We find compact wrapping conformations of dendrimer onto the nanotube surface for all the three generations of PAMAM dendrimer. The degree of wrapping is more for non-protonated dendrimer compared to the protonated dendrimer. For comparison we also study the interaction of another dendrimer,...

  2. 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....

  3. 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....... A model for the dielectrophoretic assembly of carbon nanotubes on microelectrodes was developed and several simulations were conducted using values from the available literature for the various key parameters. The model can give qualitative results regarding the parameters dominating the dielectrophoretic...

  4. 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.

  5. Carbon Nanotubes as Optical Sensors in Biomedicine.

    Science.gov (United States)

    Farrera, Consol; Torres Andón, Fernando; Feliu, Neus

    2017-11-28

    Single-walled carbon nanotubes (SWCNTs) have become potential candidates for a wide range of medical applications including sensing, imaging, and drug delivery. Their photophysical properties (i.e., the capacity to emit in the near-infrared), excellent photostability, and fluorescence, which is highly sensitive to the local environment, make SWCNTs promising optical probes in biomedicine. In this Perspective, we discuss the existing strategies for and challenges of using carbon nanotubes for medical diagnosis based on intracellular sensing as well as discuss also their biocompatibility and degradability. Finally, we highlight the potential improvements of this nanotechnology and future directions in the field of carbon nanotubes for biomedical applications.

  6. Carbon nanotubes : from molecular to macroscopic sensors

    NARCIS (Netherlands)

    Wood, J.R.; Zhao, Qing; Frogley, M.D.; Meurs, E.R.; Prins, A.D.; Peijs, A.A.J.M.; Dunstan, D.J.; Wagner, H.D.

    2000-01-01

    The components that contribute to Raman spectral shifts of single-wall carbon nanotubes (SWNT’s) embedded in polymer systems have been identified. The temperature dependence of the Raman shift can be separated into the temperature dependence of the nanotubes, the cohesive energy density of the

  7. Multifunctional smart composites with integrated carbon nanotube yarn and sheet

    Science.gov (United States)

    Chauhan, Devika; Hou, Guangfeng; Ng, Vianessa; Chaudhary, Sumeet; Paine, Michael; Moinuddin, Khwaja; Rabiee, Massoud; Cahay, Marc; Lalley, Nicholas; Shanov, Vesselin; Mast, David; Liu, Yijun; Yin, Zhangzhang; Song, Yi; Schulz, Mark

    2017-04-01

    Multifunctional smart composites (MSCs) are materials that combine the good electrical and thermal conductivity, high tensile and shear strength, good impact toughness, and high stiffness properties of metals; the light weight and corrosion resistance properties of composites; and the sensing or actuation properties of smart materials. The basic concept for MSCs was first conceived by Daniel Inman and others about 25 years ago. Current laminated carbon and glass fiber polymeric composite materials have high tensile strength and are light in weight, but they still lack good electrical and thermal conductivity, and they are sensitive to delamination. Carbon nanotube yarn and sheets are lightweight, electrically and thermally conductive materials that can be integrated into laminated composite materials to form MSCs. This paper describes the manufacturing of high quality carbon nanotube yarn and sheet used to form MSCs, and integrating the nanotube yarn and sheet into composites at low volume fractions. Various up and coming technical applications of MSCs are discussed including composite toughening for impact and delamination resistance; structural health monitoring; and structural power conduction. The global carbon nanotube overall market size is estimated to grow from 2 Billion in 2015 to 5 Billion by 2020 at a CAGR of 20%. Nanotube yarn and sheet products are predicted to be used in aircraft, wind machines, automobiles, electric machines, textiles, acoustic attenuators, light absorption, electrical wire, sporting equipment, tires, athletic apparel, thermoelectric devices, biomedical devices, lightweight transformers, and electromagnets. In the future, due to the high maximum current density of nanotube conductors, nanotube electromagnetic devices may also become competitive with traditional smart materials in terms of power density.

  8. Carbon Fiber Biocompatibility for Implants

    Directory of Open Access Journals (Sweden)

    Richard Petersen

    2016-01-01

    Full Text Available Carbon fibers have multiple potential advantages in developing high-strength biomaterials with a density close to bone for better stress transfer and electrical properties that enhance tissue formation. As a breakthrough example in biomaterials, a 1.5 mm diameter bisphenol-epoxy/carbon-fiber-reinforced composite rod was compared for two weeks in a rat tibia model with a similar 1.5 mm diameter titanium-6-4 alloy screw manufactured to retain bone implants. Results showed that carbon-fiber-reinforced composite stimulated osseointegration inside the tibia bone marrow measured as percent bone area (PBA to a great extent when compared to the titanium-6-4 alloy at statistically significant levels. PBA increased significantly with the carbon-fiber composite over the titanium-6-4 alloy for distances from the implant surfaces of 0.1 mm at 77.7% vs. 19.3% (p < 10−8 and 0.8 mm at 41.6% vs. 19.5% (p < 10−4, respectively. The review focuses on carbon fiber properties that increased PBA for enhanced implant osseointegration. Carbon fibers acting as polymer coated electrically conducting micro-biocircuits appear to provide a biocompatible semi-antioxidant property to remove damaging electron free radicals from the surrounding implant surface. Further, carbon fibers by removing excess electrons produced from the cellular mitochondrial electron transport chain during periods of hypoxia perhaps stimulate bone cell recruitment by free-radical chemotactic influences. In addition, well-studied bioorganic cell actin carbon fiber growth would appear to interface in close contact with the carbon-fiber-reinforced composite implant. Resulting subsequent actin carbon fiber/implant carbon fiber contacts then could help in discharging the electron biological overloads through electrochemical gradients to lower negative charges and lower concentration.

  9. Quantum conductance of carbon nanotube peapods

    International Nuclear Information System (INIS)

    Yoon, Young-Gui; Mazzoni, Mario S.C.; Louie, Steven G.

    2003-01-01

    We present a first-principles study of the quantum conductance of hybrid nanotube systems consisting of single-walled carbon nanotubes (SWCNTs) encapsulating either an isolated single C60 molecule or a chain of C60 molecules (nanotube peapods). The calculations show a rather weak bonding interaction between the fullerenes and the SWCNTs. The conductance of a (10,10) SWCNT with a single C60 molecule is virtually unaffected at the Fermi level, but exhibits quantized resonant reductions at the molecular levels. The nanotube peapod arrangement gives rise to high density of states for the fullerene highest occupied molecular orbital and lowest unoccupied molecular orbital bands

  10. Glucose oxidase immobilization onto carbon nanotube networking

    International Nuclear Information System (INIS)

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

    2012-01-01

    The efficient immobilization of GOX onto a carbon nanotube network through the molecular interface formed by PSE is carried out. This conclusion is based on the analysis of AFM images of the network with the adsorbed enzyme, whose globules locate mainly along a nanotube. The band corresponding to the high-frequency component of the G mode in the RR spectrum of the nanotube with adsorbed PSE is downshifted by 0.7 cm -1 relative to this band in the spectrum of pristine nanotubes. The analysis of the intensities of bands assigned to the RBM of nanotubes with adsorbed PSE in comparison with the spectrum of pristine SWNTs revealed the intensity transformation, which can be explained by a change of the resonance condition with variation of the laser energy. Thus, we concluded that PSE molecules create nanohybrids with SWNTs, which ensures the further enzyme immobilization. As the RR spectrum of an SWNT:PSE:GOX film does not essentially differ from SWNT:PSE ones, this indicates that the molecular interface (PSE) isolates the enzyme from nanotubes strongly enough. Our studies on the conductive properties of a single walled carbon nanotube network sprayed onto a quartz substrate from a solution of nanotubes in dichlorobenzene demonstrated that the I(U) dependence has nonlinear character. Most likely, the nonlinearity is related to Schottky barriers, which originate on the contact between nanotubes and the gold electrode, as well as between nanotubes with different conductivities. The deposition of bioorganic compounds (PSE and GOX) on the carbon nanotube network is accompanied by a decrease of their conductivity. Most probably, such a decrease is caused by adsorbed PSE molecules, which induce the appearance of scattering centers for charge carriers on the nanotube surface. The following GOX adsorption has practically no effect on the conductivity of the nanotube network that evidences the reliable isolation of the nanotube surface from the enzyme by means of the molecular

  11. Vibration electrospinning of Polyamide-66/Multiwall Carbon Nanotube Nanocomposite: introducing electrically conductive, ultraviolet blocking and antibacterial properties

    Directory of Open Access Journals (Sweden)

    Zohoori Salar

    2017-09-01

    Full Text Available Fabrication of electro-conductive fiber is a novel process. Nanocomposites of multiwall carbon nanotube/polyamide66 were produced by electrospinning with different amounts of multiwall carbon nanotube. Field emission scanning electron microscope and Fourier transform infrared spectroscopy of samples proved the existence of multiwall carbon nanotube distribution in polyamide 66 nanofibers. Results showed that electro conductivity of electrospun multiwall carbon nanotube/polyamide 66 nano fiber has increased in comparison with electrospun polyamide 66. Moreover, UV blocking of samples was investigated which has shown that using multiwall carbon nanotube in polyamide 66 increases UV blocking of fibers. Furthermore, anti-bacterial activity of nanocomposite showed that these nanocomposites have antibacterial property against both Staphylococcus Aureus and Escherichia Coli bacteria according to AATCC test method.

  12. Multiwall carbon nanotube microcavity arrays

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, Rajib; Butt, Haider, E-mail: h.butt@bham.ac.uk [Nanotechnology Laboratory, School of Mechanical Engineering, University of Birmingham, Birmingham B15 2TT (United Kingdom); Rifat, Ahmmed A. [Integrated Lightwave Research Group, Department of Electrical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur 50603 (Malaysia); Yetisen, Ali K.; Yun, Seok Hyun [Harvard Medical School and Wellman Center for Photomedicine, Massachusetts General Hospital, 65 Landsdowne Street, Cambridge, Massachusetts 02139 (United States); Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Dai, Qing [National Center for Nanoscience and Technology, Beijing 100190 (China)

    2016-03-21

    Periodic highly dense multi-wall carbon nanotube (MWCNT) arrays can act as photonic materials exhibiting band gaps in the visible regime and beyond terahertz range. MWCNT arrays in square arrangement for nanoscale lattice constants can be configured as a microcavity with predictable resonance frequencies. Here, computational analyses of compact square microcavities (≈0.8 × 0.8 μm{sup 2}) in MWCNT arrays were demonstrated to obtain enhanced quality factors (≈170–180) and narrow-band resonance peaks. Cavity resonances were rationally designed and optimized (nanotube geometry and cavity size) with finite element method. Series (1 × 2 and 1 × 3) and parallel (2 × 1 and 3 × 1) combinations of microcavities were modeled and resonance modes were analyzed. Higher order MWCNT microcavities showed enhanced resonance modes, which were red shifted with increasing Q-factors. Parallel microcavity geometries were also optimized to obtain narrow-band tunable filtering in low-loss communication windows (810, 1336, and 1558 nm). Compact series and parallel MWCNT microcavity arrays may have applications in optical filters and miniaturized optical communication devices.

  13. Filled and empty states of carbon nanotubes in water: Dependence ...

    Indian Academy of Sciences (India)

    WINTEC

    We have carried out a series of molecular dynamics simulations of water containing a narrow carbon nanotube ..... tant system containing the nanotube is re-equilibrated for each ... quent production phase of the simulation run, the nanotube is ...

  14. Functionalization of carbon nanotubes with silver clusters

    International Nuclear Information System (INIS)

    Cveticanin, Jelena; Krkljes, Aleksandra; Kacarevic-Popovic, Zorica; Mitric, Miodrag; Rakocevic, Zlatko; Trpkov, Djordje; Neskovic, Olivera

    2010-01-01

    In this paper, an advanced method of one-step functionalization of single and multi walled carbon nanotubes (SWCNTs and MWCNTs) using γ-irradiation was described. Two synthesis procedures, related with different reduction species, were employed. For the first time, poly(vinyl alcohol) PVA is successfully utilized as a source to reduce silver (Ag) metal ions without having any additional reducing agents to obtain Ag nanoparticles on CNTs. The decoration of carbon nanotubes with Ag nanoparticles takes place through anchoring of (PVA) on nanotube's surface. Optical properties of as-prepared samples and mechanism responsible for the functionalization of carbon nanotubes were investigated using UV-vis and FTIR spectroscopy, respectively. Decorated carbon nanotubes were visualized using microscopic techniques: transmission electron microscopy and scanning tunneling microscopy. Also, the presence of Ag on the nanotubes was confirmed using energy dispersive X-ray spectroscopy. This simple and effective method of making a carbon nanotube type of composites is of interest not only for an application in various areas of technology and biology, but for investigation of the potential of radiation technology for nanoengineering of materials.

  15. Raman spectra of filled carbon nanotubes

    International Nuclear Information System (INIS)

    Bose, S.M.; Behera, S.N.; Sarangi, S.N.; Entel, P.

    2004-01-01

    The Raman spectra of a metallic carbon nanotube filled with atoms or molecules have been investigated theoretically. It is found that there will be a three way splitting of the main Raman lines due to the interaction of the nanotube phonon with the collective excitations (plasmons) of the conduction electrons of the nanotube as well as its coupling with the phonon of the filling material. The positions and relative strengths of these Raman peaks depend on the strength of the electron-phonon interaction, phonon frequency of the filling atom and the strength of interaction of the nanotube phonon and the phonon of the filling atoms. Careful experimental studies of the Raman spectra of filled nanotubes should show these three peaks. It is also shown that in a semiconducting nanotube the Raman line will split into two and should be observed experimentally

  16. 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

  17. 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.

  18. 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.

  19. Enhanced Carbon Nanotube Ultracapacitors, Phase I

    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...

  20. Nanoscratch technique for aligning multiwalled carbon nanotubes ...

    Indian Academy of Sciences (India)

    Carbon nanotube; arc discharge; characterization; alignment; nanoscratch. 1. Introduction ... During arc discharge, when the gap between the electrodes is ∼ 1 mm, ..... increase in the D band intensity in the aligned region may not be possibly ...

  1. Carbon Nanotube Infused Launch Vehicle Structures

    Data.gov (United States)

    National Aeronautics and Space Administration — For the past 5 years Orbital ATK has been investing in, prototyping, and testing carbon nanotube infused composite structures to evaluate their impact on launch...

  2. Thermophoresis of water droplets inside carbon nanotubes

    DEFF Research Database (Denmark)

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

    2016-01-01

    Carbon Nanotubes(CNTs) offer unique possibilities as fluid conduits with applications ranging from lab on a chip devices to encapsulation media for drug delivery. CNTs feature high mechanical strength, chemical and thermalstability and biocompatibility therefore they are promising candidates...

  3. Carbon Nano-Tube (CNT) Reinforced COPV

    Data.gov (United States)

    National Aeronautics and Space Administration — Reduce the structural mass of future aerospace vehicles through the development of ultra lightweight materials and structures through the use of: Carbon nanotube...

  4. Synthesis and characterization of carbon nanotubes

    Science.gov (United States)

    Ritschel, Manfred; Bartsch, Karl; Leonhardt, Albrecht; Graff, Andreas; Täschner, Christine; Fink, Jörg

    2001-11-01

    The catalytic chemical vapor deposition (CCVD) is a very promising process with respect to large scale production of different kinds of carbon nanostructures. By modifying the deposition temperature, the catalyst material and the hydrocarbon nanofibers with herringbone structure, multi-walled nanotubes with tubular structure and single-walled nanotubes were deposited. Furthermore, layers of aligned multi-walled nanotubes could be obtained on oxidized silicon substrates coated with thin sputtered metal layers (Co, permalloy) as well as onto WC-Co hardmetals by using the microwave assisted plasma CVD process (MWCVD). The obtained carbon modifications were characterized by scanning (SEM) and transmission (TEM) electron microscopy. The hydrogen storage capability of the nanofibers and nanotubes and the electron field emission of the nanotube layers was investigated.

  5. 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.

  6. 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.

  7. 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.

  8. Evaluation of carbon fiber composites modified by in situ incorporation of carbon nanofibers

    Directory of Open Access Journals (Sweden)

    André Navarro de Miranda

    2011-12-01

    Full Text Available Nano-carbon materials, such as carbon nanotubes and carbon nanofibers, are being thought to be used as multifunctional reinforcement in composites. The growing of carbon nanofiber at the carbon fiber/epoxy interface results in composites having better electrical properties than conventional carbon fiber/epoxy composites. In this work, carbon nanofibers were grown in situ over the surface of a carbon fiber fabric by chemical vapor deposition. Specimens of carbon fiber/nanofiber/epoxy (CF/CNF/epoxy composites were molded and electrical conductivity was measured. Also, the CF/CNF/epoxy composites were tested under flexure and interlaminar shear. The results showed an overall reduction in mechanical properties as a function of added nanofiber, although electrical conductivity increased up to 74% with the addition of nanofibers. Thus CF/CNF/epoxy composites can be used as electrical dissipation discharge materials.

  9. Ballistic resistance capacity of carbon nanotubes

    International Nuclear Information System (INIS)

    Mylvaganam, Kausala; Zhang, L C

    2007-01-01

    Carbon nanotubes have high strength, light weight and excellent energy absorption capacity and therefore have great potential applications in making antiballistic materials. By examining the ballistic impact and bouncing-back processes on carbon nanotubes, this investigation shows that nanotubes with large radii withstand higher bullet speeds and the ballistic resistance is the highest when the bullet hits the centre of the CNT; the ballistic resistance of CNTs will remain the same on subsequent bullet strikes if the impact is after a small time interval

  10. Improvements in Production of Single-Walled Carbon Nanotubes

    Science.gov (United States)

    Balzano, Leandro; Resasco, Daniel E.

    2009-01-01

    A continuing program of research and development has been directed toward improvement of a prior batch process in which single-walled carbon nanotubes are formed by catalytic disproportionation of carbon monoxide in a fluidized-bed reactor. The overall effect of the improvements has been to make progress toward converting the process from a batch mode to a continuous mode and to scaling of production to larger quantities. Efforts have also been made to optimize associated purification and dispersion post processes to make them effective at large scales and to investigate means of incorporating the purified products into composite materials. The ultimate purpose of the program is to enable the production of high-quality single-walled carbon nanotubes in quantities large enough and at costs low enough to foster the further development of practical applications. The fluidized bed used in this process contains mixed-metal catalyst particles. The choice of the catalyst and the operating conditions is such that the yield of single-walled carbon nanotubes, relative to all forms of carbon (including carbon fibers, multi-walled carbon nanotubes, and graphite) produced in the disproportionation reaction is more than 90 weight percent. After the reaction, the nanotubes are dispersed in various solvents in preparation for end use, which typically involves blending into a plastic, ceramic, or other matrix to form a composite material. Notwithstanding the batch nature of the unmodified prior fluidized-bed process, the fluidized-bed reactor operates in a continuous mode during the process. The operation is almost entirely automated, utilizing mass flow controllers, a control computer running software specific to the process, and other equipment. Moreover, an important inherent advantage of fluidized- bed reactors in general is that solid particles can be added to and removed from fluidized beds during operation. For these reasons, the process and equipment were amenable to

  11. High Volume Fraction Carbon Nanotube Composites for Aerospace Applications

    Science.gov (United States)

    Siochi, E. J.; Kim, J.-W.; Sauti, G.; Cano, R. J.; Wincheski, R. A.; Ratcliffe, J. G.; Czabaj, M.

    2016-01-01

    Reported mechanical properties of carbon nanotubes (CNTs) at the nanoscale suggest their potential to enable significantly lighter structures of interest for space applications. However, their utility depends on the retention of these properties in bulk material formats that permit practical fabrication of large structures. This presentation summarizes recent progress made to produce carbon nanotube composites with specific tensile properties that begin to rival those of carbon fiber reinforced polymer composites. CNT content in these nanocomposites was greater than 70% by weight. Tested nanocomposite specimens were fabricated from kilometers or tens of square meters of CNT, depending on the starting material format. Processing methods to yield these results, and characterization and testing to evaluate the performance of these composites will be discussed. The final objective is the demonstration of a CNT composite overwrapped pressure vessel to be flight tested in the Fall of 2016.

  12. Method for nano-pumping using carbon nanotubes

    Science.gov (United States)

    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.

  13. Amorphous molecular junctions produced by ion irradiation on carbon nanotubes

    International Nuclear Information System (INIS)

    Wang Zhenxia; Yu Liping; Zhang Wei; Ding Yinfeng; Li Yulan; Han Jiaguang; Zhu Zhiyuan; Xu Hongjie; He Guowei; Chen Yi; Hu Gang

    2004-01-01

    Experiments and molecular dynamics have demonstrated that electron irradiation could create molecular junctions between crossed single-wall carbon nanotubes. Recently molecular dynamics computation predicted that ion irradiation could also join single-walled carbon nanotubes. Employing carbon ion irradiation on multi-walled carbon nanotubes, we find that these nanotubes evolve into amorphous carbon nanowires, more importantly, during the process of which various molecular junctions of amorphous nanowires are formed by welding from crossed carbon nanotubes. It demonstrates that ion-beam irradiation could be an effective way not only for the welding of nanotubes but also for the formation of nanowire junctions

  14. Functionalization of vertically aligned carbon nanotubes.

    Science.gov (United States)

    Van Hooijdonk, Eloise; Bittencourt, Carla; Snyders, Rony; Colomer, Jean-François

    2013-01-01

    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.

  15. Carbon nanotube stationary phases for microchip electrochromatography

    DEFF Research Database (Denmark)

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

    , 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......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...

  16. 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.

  17. Enhancement in ballistic performance of composite hard armor through carbon nanotubes

    Directory of Open Access Journals (Sweden)

    Jason Gibson

    2013-12-01

    Full Text Available The use of carbon nanotubes in composite hard armor is discussed in this study. The processing techniques to make various armor composite panels consisting of Kevlar®29 woven fabric in an epoxy matrix and the subsequent V50 test results for both 44 caliber soft-point rounds and 30 caliber FSP (fragment simulated projectile threats are presented. A 6.5% improvement in the V50 test results was found for a combination of 1.65 wt% loading of carbon nanotubes and 1.65 wt% loading of milled fibers. The failure mechanism of carbon nanotubes during the ballistic event is discussed through scanning electron microscope images of the panels after the failure. Raman Spectroscopy was also utilized to evaluate the residual strain in the Kevlar®29 fibers post shoot. The Raman Spectroscopy shows a Raman shift of 25 cm−1 for the Kevlar®29 fiber utilized in the composite panel that had an enhancement in the V50 performance by using milled fiber and multi-walled carbon nanotubes. Evaluating both scenarios where an improvement was made and other panels without any improvement allows for understanding of how loading levels and synergistic effects between carbon nanotubes and milled fibers can further enhance ballistic performance.

  18. Electrostatically Induced Carbon Nanotube Alignment for Polymer Composite Applications

    Science.gov (United States)

    Chapkin, Wesley Aaron

    We have developed a non-invasive technique utilizing polarized Raman spectroscopy to measure changes in carbon nanotube (CNT) alignment in situ and in real time in a polymer matrix. With this technique, we have confirmed the prediction of faster alignment for CNTs in higher electric fields. Real-time polarized Raman spectroscopy also allows us to demonstrate the loss of CNT alignment that occurs after the electric field is removed, which reveals the need for fast polymerization steps or the continued application of the aligning force during polymerization to lock in CNT alignment. Through a study on the effect of polymer viscosity on the rate of CNT alignment, we have determined that shear viscosity serves as the controlling mechanism for CNT rotation. This finding matches literature modeling of rigid rod mobility in a polymer melt and demonstrates that the rotational mobility of CNTs can be explained by a continuum model even though the diameters of single-walled CNTs are 1-2 nm. The viscosity dependence indicates that the manipulation of temperature (and indirectly viscosity) will have a direct effect on the rate of CNT alignment, which could prove useful in expediting the manufacturing of CNT-reinforced composites cured at elevated temperatures. Using real-time polarized Raman spectroscopy, we also demonstrate that electric fields of various strengths lead not only to different speeds of CNT rotation but also to different degrees of alignment. We hypothesize that this difference in achievable alignment results from discrete populations of nanotubes based on their length. The results are then explained by balancing the alignment energy for a given electric field strength with the randomizing thermal energy of the system. By studying the alignment dynamics of different CNT length distributions, we show that different degrees of alignment achieved as a function of the applied electric field strength are directly related to the square of the nanotube length. This

  19. Carbon Nanotube Templated Microfabrication of Porous Silicon-Carbon Materials

    Science.gov (United States)

    Song, Jun; Jensen, David; Dadson, Andrew; Vail, Michael; Linford, Matthew; Vanfleet, Richard; Davis, Robert

    2010-10-01

    Carbon nanotube templated microfabrication (CNT-M) of porous materials is demonstrated. Partial chemical infiltration of three dimensional carbon nanotube structures with silicon resulted in a mechanically robust material, precisely structured from the 10 nm scale to the 100 micron scale. Nanoscale dimensions are determined by the diameter and spacing of the resulting silicon/carbon nanotubes while the microscale dimensions are controlled by lithographic patterning of the CNT growth catalyst. We demonstrate the utility of this hierarchical structuring approach by using CNT-M to fabricate thin layer chromatography (TLC) separations media with precise microscale channels for fluid flow control and nanoscale porosity for high analyte capacity.

  20. 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.

  1. Physical removal of metallic carbon nanotubes from nanotube network devices using a thermal and fluidic process

    International Nuclear Information System (INIS)

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

    2013-01-01

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

  2. EB treatment of carbon nanotube-reinforced polymer composites

    International Nuclear Information System (INIS)

    Szebényi, G.; Romhány, G.; Vajna, B.; Czvikovszky, T.

    2012-01-01

    A small amount — less than 0.5% — carbon nanotube reinforcement may improve the mechanical properties of epoxy based composite materials significantly. The basic technical problem on one side is the dispersion of the nanotubes into the viscous matrix resin, namely, the fine powder-like — less than 100 nanometer diameter — nanotubes are prone to form aggregates. On the other side, the good connection between the nanofiber and matrix, which is determining the success of the reinforcement, requires some efficient adhesion promoting treatment. The goal of our research was to give one such treatment capable of industrial size application. A two step curing epoxy/vinylester resin process technology has been developed where the epoxy component has been cured conventionally, while the vinylester has been cured by electron treatment afterwards. The sufficient irradiation dose has been selected according to Raman spectroscopy characterization. Using the developed hybrid resin system hybrid composites containing carbon fibers and multiwalled carbon nanotubes have been prepared. The effect of the electron beam induced curing of the vinylester resin on the mechanical properties of the composites has been characterized by three point bending and interlaminar shear tests, which showed clearly the superiority of the developed resin system. The results of the mechanical tests have been supported by AFM studies of the samples, which showed that the difference in the viscoelastic properties of the matrix constituents decreased significantly by the electron beam treatment.

  3. Synthesis and Characterization Carbon Nanotubes Doped Carbon Aerogels

    Science.gov (United States)

    Xu, Yuelong; Yan, Meifang; Liu, Zhenfa

    2017-12-01

    Polycondensation of phloroglucinol, resorcinol and formaldehyde with carbon nanotube (CNT) as the additives, using sodium carbonate as the catalyst, leads to the formation of CNT - doped carbon aerogels. The structure of carbon aerogels (CAs) with carbon nanotubes (CNTs) were characterized by X-ray diffraction and scanning electron microscopy. The specific surface area, pore size distribution and pore volume were measured by surface area analyzer. The results show that when the optimum doping dosage is 5%, the specific surface area of CNT - doped carbon aerogel is up to 665 m2 g-1 and exhibit plentiful mesoporous.

  4. 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

  5. Carbon Fiber from Biomass

    Energy Technology Data Exchange (ETDEWEB)

    Milbrandt, Anelia [Clean Energy Manufacturing Analysis Center, Godlen, CO (United States); Booth, Samuel [Clean Energy Manufacturing Analysis Center, Godlen, CO (United States)

    2016-09-01

    Carbon fiber (CF), known also as graphite fiber, is a lightweight, strong, and flexible material used in both structural (load-bearing) and non-structural applications (e.g., thermal insulation). The high cost of precursors (the starting material used to make CF, which comes predominately from fossil sources) and manufacturing have kept CF a niche market with applications limited mostly to high-performance structural materials (e.g., aerospace). Alternative precursors to reduce CF cost and dependence on fossil sources have been investigated over the years, including biomass-derived precursors such as rayon, lignin, glycerol, and lignocellulosic sugars. The purpose of this study is to provide a comprehensive overview of CF precursors from biomass and their market potential. We examine the potential CF production from these precursors, the state of technology and applications, and the production cost (when data are available). We discuss their advantages and limitations. We also discuss the physical properties of biomass-based CF, and we compare them to those of polyacrylonitrile (PAN)-based CF. We also discuss manufacturing and end-product considerations for bio-based CF, as well as considerations for plant siting and biomass feedstock logistics, feedstock competition, and risk mitigation strategies. The main contribution of this study is that it provides detailed technical and market information about each bio-based CF precursor in one document while other studies focus on one precursor at a time or a particular topic (e.g., processing). Thus, this publication allows for a comprehensive view of the CF potential from all biomass sources and serves as a reference for both novice and experienced professionals interested in CF production from alternative sources.

  6. 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.

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

    DEFF Research Database (Denmark)

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

    2007-01-01

    The authors investigate the thermally driven mass transport of gold nanoparticles confined inside carbon nanotubes using molecular dynamics simulations. The observed thermophoretic motion of the gold nanoparticles correlates with the phonon dispersion exhibited by a standard carbon nanotube and...

  8. 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.

  9. Carbon nanotubes : their synthesis and integration into nanofabricated structures

    NARCIS (Netherlands)

    Druzhinina, Tamara

    2011-01-01

    The field of nanotechnology has experienced constantly increasing interest over the past decades both from industry and academy. Commonly used nanomaterials include: nanoparticles, nanowires, quantum dots, fullerenes, and carbon nanotubes. Carbon nanotubes, in particular, are promising building

  10. Thermal conductivity and thermal rectification in unzipped carbon nanotubes

    International Nuclear Information System (INIS)

    Ni Xiaoxi; Li Baowen; Zhang Gang

    2011-01-01

    We study the thermal transport in completely unzipped carbon nanotubes, which are called graphene nanoribbons, partially unzipped carbon nanotubes, which can be seen as carbon-nanotube-graphene-nanoribbon junctions, and carbon nanotubes by using molecular dynamics simulations. It is found that the thermal conductivity of a graphene nanoribbon is much less than that of its perfect carbon nanotube counterparts because of the localized phonon modes at the boundary. A partially unzipped carbon nanotube has the lowest thermal conductivity due to additional localized modes at the junction region. More strikingly, a significant thermal rectification effect is observed in both partially unzipped armchair and zigzag carbon nanotubes. Our results suggest that carbon-nanotube-graphene-nanoribbon junctions can be used in thermal energy control.

  11. 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 ...

  12. Electrical conductivity of metal–carbon nanotube structures: Effect of ...

    Indian Academy of Sciences (India)

    Administrator

    The electrical properties of asymmetric metal–carbon nanotube (CNT) structures have been studied using ... The models with asymmetric metal contacts and carbon nanotube bear resemblance to experimental ... ordinary mechanical strength.

  13. 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.

  14. Carbon Nanotubes and Chronic Granulomatous Disease

    Directory of Open Access Journals (Sweden)

    Barbara P. Barna

    2014-06-01

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

  15. Carbon Nanotube Based Molecular Electronics and Motors: A View from Classical and Quantum Dynamics Simulations

    Science.gov (United States)

    Srivastava, Deepak; Saini, Subhash (Technical Monitor)

    1998-01-01

    The tubular forms of fullerenes popularly known as carbon nanotubes are experimentally produced as single-, multiwall, and rope configurations. The nanotubes and nanoropes have shown to exhibit unusual mechanical and electronic properties. The single wall nanotubes exhibit both semiconducting and metallic behavior. In short undefected lengths they are the known strongest fibers which are unbreakable even when bent in half. Grown in ropes their tensile strength is approximately 100 times greater than steel at only one sixth the weight. Employing large scale classical and quantum molecular dynamics simulations we will explore the use of carbon nanotubes and carbon nanotube junctions in 2-, 3-, and 4-point molecular electronic device components, dynamic strength characterization for compressive, bending and torsional strains, and chemical functionalization for possible use in a nanoscale molecular motor. The above is an unclassified material produced for non-competitive basic research in the nanotechnology area.

  16. 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.

  17. Experimental Studies of Carbon Nanotube Materials for Space Radiators

    Science.gov (United States)

    SanSoucie, MIchael P.; Rogers, Jan R.; Craven, Paul D.; Hyers, Robert W.

    2012-01-01

    Game ]changing propulsion systems are often enabled by novel designs using advanced materials. Radiator performance dictates power output for nuclear electric propulsion (NEP) systems. Carbon nanotubes (CNT) and carbon fiber materials have the potential to offer significant improvements in thermal conductivity and mass properties. A test apparatus was developed to test advanced radiator designs. This test apparatus uses a resistance heater inside a graphite tube. Metallic tubes can be slipped over the graphite tube to simulate a heat pipe. Several sub ]scale test articles were fabricated using CNT cloth and pitch ]based carbon fibers, which were bonded to a metallic tube using an active braze material. The test articles were heated up to 600 C and an infrared (IR) camera captured the results. The test apparatus and experimental results are presented here.

  18. Carbon fiber reinforced asphalt concrete

    International Nuclear Information System (INIS)

    Jahromi, Saeed G.

    2008-01-01

    Fibers are often used in the manufacture of other materials. For many years, they have been utilized extensively in numerous applications in civil engineering. Fiber-reinforcement refers to incorporating materials with desired properties within some other materials lacking those properties. Use of fibers is not a new phenomenon, as the technique of fiber-reinforced bitumen began early as 1950. In all industrialized countries today, nearly all concretes used in construction are reinforced. A multitude of fibers and fiber materials are being introduced in the market regularly. The present paper presents characteristics and properties of carbon fiber-reinforced asphalt mixtures, which improve the performance of pavements. To evaluate the effect of fiber contents on bituminous mixtures, laboratory investigations were carried out on the samples with and without fibers. During the course of this study, various tests were undertaken, applying Marshall Test indirect tensile test, creep test and resistance to fatigue cracking by using repeated load indirect tensile test. Carbon fiber exhibited consistency in results and as such it was observed that the addition of fiber does affect the properties of bituminous mixtures, i.e. an increase in its stability and decrease in the flow value as well as an increase in voids in the mix. Results indicate that fibers have the potential to resist structural distress in pavement, in the wake of growing traffic loads and thus improve fatigue by increasing resistance to cracks or permanent deformation. On the whole, the results show that the addition of carbon fiber will improve some of the mechanical properties like fatigue and deformation in the flexible pavement. (author)

  19. Carbon Fiber Technology Facility (CFTF)

    Data.gov (United States)

    Federal Laboratory Consortium — Functionally within the MDF, ORNL operates DOE’s unique Carbon Fiber Technology Facility (CFTF)—a 42,000 ft2 innovative technology facility and works with leading...

  20. Carbon Nanotube Underwater Acoustic Thermophone

    Science.gov (United States)

    2016-09-23

    nanotubes (unless encapsulated or housed) are quite fragile and are susceptible to disintegration especially if the nanotubes are touched or moved too...The acoustic impedance (defined as the product of material density and sound speed) of the top shell 12 should match the Attorney Docket No. 300009

  1. 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.

  2. 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.

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

    Science.gov (United States)

    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.

  4. Carbon nanotubes for thermal interface materials in microelectronic packaging

    Science.gov (United States)

    Lin, Wei

    , an in situ functionalization process has for the first time been demonstrated. The in situ functionalization renders the vertically aligned carbon nanotubes a proper chemical reactivity for forming chemical bonding with other substrate materials such as gold and silicon. 2. An ultrafast microwave annealing process has been developed to reduce the defect density in vertically aligned carbon nanotubes. Raman and thermogravimetric analyses have shown a distinct defect reduction in the CNTs annealed in microwave for 3 min. Fibers spun from the as-annealed CNTs, in comparison with those from the pristine CNTs, show increases of ˜35% and ˜65%, respectively, in tensile strength (˜0.8 GPa) and modulus (˜90 GPa) during tensile testing; an ˜20% improvement in electrical conductivity (˜80000 S m-1) was also reported. The mechanism of the microwave response of CNTs was discussed. Such a microwave annealing process has been extended to the preparation of reduced graphene oxide. 3. Based on the fundamental understanding of interfacial thermal transport and surface chemistry of metals and carbon nanotubes, two major transfer/assembling processes have been developed: molecular bonding and metal bonding. Effective improvement of the interfacial thermal transport has been achieved by the interfacial bonding. 4. The thermal diffusivity of vertically aligned carbon nanotube (VACNT, multi-walled) films was measured by a laser flash technique, and shown to be ˜30 mm2 s-1 along the tube-alignment direction. The calculated thermal conductivities of the VACNT film and the individual CNTs are ˜27 and ˜540 W m-1 K-1, respectively. The technique was verified to be reliable although a proper sampling procedure is critical. A systematic parametric study of the effects of defects, buckling, tip-to-tip contacts, packing density, and tube-tube interaction on the thermal diffusivity was carried out. Defects and buckling decreased the thermal diffusivity dramatically. An increased packing

  5. Carbon nanotubes in neuroregeneration and repair.

    Science.gov (United States)

    Fabbro, Alessandra; Prato, Maurizio; Ballerini, Laura

    2013-12-01

    In the last decade, we have experienced an increasing interest and an improved understanding of the application of nanotechnology to the nervous system. The aim of such studies is that of developing future strategies for tissue repair to promote functional recovery after brain damage. In this framework, carbon nanotube based technologies are emerging as particularly innovative tools due to the outstanding physical properties of these nanomaterials together with their recently documented ability to interface neuronal circuits, synapses and membranes. This review will discuss the state of the art in carbon nanotube technology applied to the development of devices able to drive nerve tissue repair; we will highlight the most exciting findings addressing the impact of carbon nanotubes in nerve tissue engineering, focusing in particular on neuronal differentiation, growth and network reconstruction. © 2013.

  6. Carbon Nanotube Bolometer for Absolute FTIR Spectroscopy

    Science.gov (United States)

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

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

  7. 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.

  8. 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.

  9. A carbon nanotube optical rectenna

    Science.gov (United States)

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

    2015-12-01

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

  10. Nitrogen in highly crystalline carbon nanotubes

    International Nuclear Information System (INIS)

    Ducati, C; Koziol, K; Stavrinadis, A; Friedrichs, S; Windle, A H; Midgley, P A

    2006-01-01

    Multiwall carbon nanotubes (MWCNTs) with an unprecedented degree of internal order were synthesised by chemical vapour deposition (CVD) adding a nitrogen-containing compound to the hydrocarbon feedstock. Ferrocene was used as the metal catalyst precursor. The remarkable crystallinity of these nanotubes lies both in the isochirality and in the crystallographic register of their walls, as demonstrated by electron diffraction and high resolution electron microscopy experiments. High resolution transmission electron microscopy analysis shows that the walls of the nanotubes consist of truncated stacked cones, instead of perfect cylinders, with a range of apex angles that appears to be related to the nitrogen concentration in the synthesis process. The structure of armchair, zigzag and chiral nanotubes is modelled and discussed in terms of density of topological defects, providing an interesting comparison with our microscopy experiments. A growth mechanism based on the interplay of base- and tip-growth is proposed to account for our experimental observations

  11. 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.

  12. 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.

  13. 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.

  14. Carbon nanotube reinforced hybrid composites: Computational modeling of environmental fatigue and usability for wind blades

    DEFF Research Database (Denmark)

    Dai, Gaoming; Mishnaevsky, Leon

    2015-01-01

    The potential of advanced carbon/glass hybrid reinforced composites with secondary carbon nanotube reinforcement for wind energy applications is investigated here with the use of computational experiments. Fatigue behavior of hybrid as well as glass and carbon fiber reinforced composites...... with the secondary CNT reinforcements (especially, aligned tubes) present superior fatigue performances than those without reinforcements, also under combined environmental and cyclic mechanical loading. This effect is stronger for carbon composites, than for hybrid and glass composites....

  15. Safety considerations for graphene: lessons learnt from carbon nanotubes.

    Science.gov (United States)

    Bussy, Cyrill; Ali-Boucetta, Hanene; Kostarelos, Kostas

    2013-03-19

    Many consider carbon nanomaterials the poster children of nanotechnology, attracting immense scientific interest from many disciplines and offering tremendous potential in a diverse range of applications due to their extraordinary properties. Graphene is the youngest in the family of carbon nanomaterials. Its isolation, description, and mass fabrication has followed that of fullerenes and carbon nanotubes. Graphene's development and its adoption by many industries will increase unintended or intentional human exposure, creating the need to determine its safety profile. In this Account, we compare the lessons learned from the development of carbon nanotubes with what is known about graphene, based on our own investigations and those of others. Despite both being carbon-based, nanotubes and graphene are two very distinct nanomaterials. We consider the key physicochemical characteristics (structure, surface, colloidal properties) for graphene and carbon nanotubes at three different physiological levels: cellular, tissue, and whole body. We summarize the evidence for health effects of both materials at all three levels. Overall, graphene and its derivatives are characterized by a lower aspect ratio, larger surface area, and better dispersibility in most solvents compared to carbon nanotubes. Dimensions, surface chemistry, and impurities are equally important for graphene and carbon nanotubes in determining both mechanistic (aggregation, cellular processes, biodistribution, and degradation kinetics) and toxicological outcomes. Colloidal dispersions of individual graphene sheets (or graphene oxide and other derivatives) can easily be engineered without metallic impurities, with high stability and less aggregation. Very importantly, graphene nanostructures are not fiber-shaped. These features theoretically offer significant advantages in terms of safety over inhomogeneous dispersions of fiber-shaped carbon nanotubes. However, studies that directly compare graphene with

  16. Carbon nanotube and graphene nanoribbon interconnects

    CERN Document Server

    Das, Debaprasad

    2014-01-01

    "The book, Caron Nanotube and Graphene Nanoribbon Interconnects, authored by Drs. Debapraad Das and Hafizur Rahaman serves as a good source of material on CNT and GNR interconnects for readers who wish to get into this area and also for practicing engineers who would like to be updated in advances of this field."-Prof. Ashok Srivastava, Louisiana State University, Baton Rouge, USA"Mathematical analysis included in each and every chapter is the main strength of the materials. ... The book is very precise and useful for those who are working in this area. ... highly focused, very compact, and easy to apply. ... This book depicts a detailed analysis and modelling of carbon nanotube and graphene nanoribbon interconnects. The book also covers the electrical circuit modelling of carbon nanotubes and graphene nanoribbons."-Prof. Chandan Kumar Sarkar, Jadavpur University, Kolkata, India.

  17. Electrical measurements on submicronic synthetic conductors : carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Langer, L [Unite de Physico-Chimie et de Physique des Materiaux, Univ. Catholique de Louvain, Louvain-la-Neuve (Belgium); Stockman, L [Lab. voor Vaste Stof-Fysika en Magnetisme, Katholieke Univ. Leuven (Belgium); Heremans, J P [Physics Dept., General Motors Research, Warren, MI (United States); Bayot, V [Unite de Physico-Chimie et de Physique des Materiaux, Univ. Catholique de Louvain, Louvain-la-Neuve (Belgium); Olk, C H [Physics Dept., General Motors Research, Warren, MI (United States); Haesendonck, C van [Lab. voor Vaste Stof-Fysika en Magnetisme, Katholieke Univ. Leuven (Belgium); Bruynseraede, Y [Lab. voor Vaste Stof-Fysika en Magnetisme, Katholieke Univ. Leuven (Belgium); Issi, J P [Unite de Physico-Chimie et de Physique des Materiaux, Univ. Catholique de Louvain, Louvain-la-Neuve (Belgium)

    1995-03-15

    The synthesis of very small samples has raised the need for a drastic miniaturization of the classical four-probe technique in order to realize electrical resistance measurements. Two methods to realize electrical contacts on very small fibers are described here. Using classical photolithography the electrical resistivity of a submicronic catalytic chemical vapour deposited filament is estimated. Scanning tunneling microscopy (STM) lithography allowed to attach small gold contacts to a small bundle (diameter 50 nm) of carbon nanotubes. This bundle is found to exhibit a semimetallic behavior at higher temperature and an unexpected drop of the electrical resistivity at lower temperature. (orig.)

  18. Application of Nanoparticles/Nanowires and Carbon Nanotubes for Breast Cancer Research

    National Research Council Canada - National Science Library

    Panchapakesan, Balaji

    2005-01-01

    .... Variety of techniques such as fabrication of single wall carbon nanotubes, functionalization of nanotubes with antibodies, interaction of cells with antibodies on nanotube surfaces, and finally cell...

  19. Immobilization of redox mediators on functionalized carbon nanotube

    Indian Academy of Sciences (India)

    Chemical functionalization of single-walled carbon nanotubes with redox mediators, namely, toluidine blue and thionin have been carried out and the performance of graphite electrode modified with functionalized carbon nanotubes is described. Mechanical immobilization of functionalized single-walled nanotube (SWNT) ...

  20. Black silicon maskless templates for carbon nanotube forests

    DEFF Research Database (Denmark)

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

    2013-01-01

    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...

  1. Nanotubes on Display: How Carbon Nanotubes Can Be Integrated into Electronic Displays

    KAUST Repository

    Opatkiewicz, Justin; LeMieux, Melburne C.; Bao, Zhenan

    2010-01-01

    Random networks of single-walled carbon nanotubes show promise for use in the field of flexible electronics. Nanotube networks have been difficult to utilize because of the mixture of electronic types synthesized when grown. A variety of separation

  2. 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

  3. Carbon nanotubes for high-performance logic

    NARCIS (Netherlands)

    Chen, Zhihong; Philip Wong, H.-S.; Mitra, S.; Bol, A.A.; Peng, Lianmao; Hills, Gage; Thissen, N.F.W.

    2014-01-01

    Single-wall carbon nanotubes (CNTs) were discovered in 1993 and have been an area of intense research since then. They offer the right dimensions to explore material science and physical chemistry at the nanoscale and are the perfect system to study low-dimensional physics and transport. In the past

  4. 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…

  5. New approach to synthesis of carbon nanotubes

    International Nuclear Information System (INIS)

    Ha, Jong Keun; Choi, Kyo Hong; Cho, Kwon Koo; Kim, Ki Won; Nam, Tae Hyun; Ahn, Hyo Jun; Ahn, Jou Hyun; Cho, Gyu Bong

    2007-01-01

    Carbon nanotubes (CNTs) have been synthesized through chemical vapor deposition in argon gas atmosphere using Fe-2.5%Mo alloyed nanoparticles as a catalyst and H 2 /CH 4 gas mixture as a reaction gas. Fe-2.5 wt.%Mo alloyed nanoparticles with average diameter of 7, 20, 45 and 85 nm are prepared by the chemical vapor condensation process using the pyrolysis of iron pentacarbonyl (Fe(CO) 5 ) and molybdenum hexacarbonyl (Mo(CO) 6 ). The morphologies of the CNTs are controlled by adjusting the nanoparticle size, reaction gas ratio and reaction temperature. With decreasing nanoparticle size under the same experimental conditions, the degree of crystalline perfection increases gradually and the morphologies of the carbon nanotubes vary from multi wall carbon nanotubes to single wall carbon nanotubes. Also, the ratio of reaction gas has an effect on the morphology and the degree of crystallinity of CNTs. In this work, it is suggested that morphology, diameter and degree of crystallinity of CNTs could be controlled by adjusting the reaction gas ratio, reaction temperature and catalyst size

  6. 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.

  7. Carbon Nanotubes as Thermally Induced Water Pumps

    DEFF Research Database (Denmark)

    Oyarzua, Elton; Walther, Jens Honore; Megaridis, Constantine M

    2017-01-01

    Thermal Brownian motors (TBMs) are nanoscale machines that exploit thermal fluctuations to provide useful work. We introduce a TBM-based nanopump which enables continuous water flow through a carbon nanotube (CNT) by imposing an axial thermal gradient along its surface. We impose spatial asymmetry...

  8. 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...

  9. 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...

  10. 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...

  11. 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...

  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. Chemical vapor deposition of carbon nanotube forests

    International Nuclear Information System (INIS)

    Robertson, J.; Zhong, G.; Esconjauregui, S.; Zhang, C.; Fouquet, M.; Hofmann, S.

    2012-01-01

    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)

  14. Carbon Nanotubes in Drug and Gene Delivery

    Science.gov (United States)

    Karimi, Mahdi; Ghasemi, Amir; Mirkiani, Soroush; Moosavi Basri, Seyed Masoud; Hamblin, Michael R.

    2017-10-01

    Recent important discoveries and developments in nanotechnology have had a remarkable and ever-increasing impact on many industries, especially materials science, pharmaceuticals, and biotechnology. Within this book, the authors describe different features of carbon nanotubes, survey the properties of both the multi-walled and single-walled varieties, and cover their applications in drug and gene delivery.

  15. 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.

  16. Analysis of ionic conductance of carbon nanotubes

    NARCIS (Netherlands)

    Biesheuvel, P.M.; Bazant, M.Z.

    2016-01-01

    We use space-charge (SC) theory (also called the capillary pore model) to describe the ionic conductance, G, of charged carbon nanotubes (CNTs). Based on the reversible adsorption of hydroxyl ions to CNT pore walls, we use a Langmuir isotherm for surface ionization and make calculations as a

  17. Fluorescently labeled bionanotransporters of nucleic acid based on carbon nanotubes

    International Nuclear Information System (INIS)

    Novopashina, D.S.; Apartsin, E.K.; Venyaminova, A.G.

    2012-01-01

    We propose an approach to the design of a new type of hybrids of oligonucleotides with fluorescein-functionalized single-walled carbon nanotubes. The approach is based on stacking interactions of functionalized nanotubes with pyrene residues in conjugates of oligonucleotides. The amino- and fluorescein-modified single walled carbon nanotubes are obtained, and their physico-chemical properties are investigated. The effect of the functionalization type of carbon nanotubes on the efficacy of the sorption of pyrene conjugates of oligonucleotides was examined. The proposed noncovalent hybrids of fluorescein-labeled carbon nanotubes with oligonucleotides may be used for the intracellular transport of functional nucleic acids.

  18. Degradation of multiwall carbon nanotubes by bacteria

    International Nuclear Information System (INIS)

    Zhang, Liwen; Petersen, Elijah J.; Habteselassie, Mussie Y.; Mao, Liang; Huang, Qingguo

    2013-01-01

    Understanding the environmental transformation of multiwall carbon nanotubes (MWCNTs) is important to their life cycle assessment and potential environmental impacts. We report that a bacterial community is capable of degrading 14 C-labeled MWCNTs into 14 CO 2 in the presence of an external carbon source via co-metabolism. Multiple intermediate products were detected, and genotypic characterization revealed three possible microbial degraders: Burkholderia kururiensis, Delftia acidovorans, and Stenotrophomonas maltophilia. This result suggests that microbe/MWCNTs interaction may impact the long-term fate of MWCNTs. Highlights: •Mineralization of MWCNTs by a bacterial community was observed. •The mineralization required an external carbon source. •Multiple intermediate products were identified in the MWCNT degrading culture. •Three bacterial species were found likely responsible for MWCNT degradation. -- The 14 C-labeled multiwall carbon nanotubes can be degraded to 14 CO 2 and other byproducts by a bacteria community under natural conditions

  19. 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.

  20. Exploring the Immunotoxicity of Carbon Nanotubes

    Science.gov (United States)

    Yu, Yanmei; Zhang, Qiu; Mu, Qingxin; Zhang, Bin; Yan, Bing

    2008-08-01

    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.

  1. 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...

  2. Decoration of Multi-walled Carbon Nanotubes by Metal ...

    African Journals Online (AJOL)

    NICO

    tures inside the nanotubes to increase the available surface for catalysis6 or in ... most common method to decorate CNTs by metal nanoparticles and metal oxides due .... 2.6 Characterization of Carbon Nanotubes, Metal Nano- particles and ...

  3. Intrinsic Chirality Origination in Carbon Nanotubes.

    Science.gov (United States)

    Pierce, Neal; Chen, Gugang; P Rajukumar, Lakshmy; Chou, Nam Hawn; Koh, Ai Leen; Sinclair, Robert; Maruyama, Shigeo; Terrones, Mauricio; Harutyunyan, Avetik R

    2017-10-24

    Elucidating the origin of carbon nanotube chirality is key for realizing their untapped potential. Currently, prevalent theories suggest that catalyst structure originates chirality via an epitaxial relationship. Here we studied chirality abundances of carbon nanotubes grown on floating liquid Ga droplets, which excludes the influence of catalyst features, and compared them with abundances grown on solid Ru nanoparticles. Results of growth on liquid droplets bolsters the intrinsic preference of carbon nuclei toward certain chiralities. Specifically, the abundance of the (11,1)/χ = 4.31° tube can reach up to 95% relative to (9,4)/χ = 17.48°, although they have exactly the same diameter, (9.156 Å). However, the comparative abundances for the pair, (19,3)/χ = 7.2° and (17,6)/χ = 14.5°, with bigger diameter, (16.405 Å), fluctuate depending on synthesis temperature. The abundances of the same pairs of tubes grown on floating solid polyhedral Ru nanoparticles show completely different trends. Analysis of abundances in relation to nucleation probability, represented by a product of the Zeldovich factor and the deviation interval of a growing nuclei from equilibrium critical size, explain the findings. We suggest that the chirality in the nanotube in general is a result of interplay between intrinsic preference of carbon cluster and induction by catalyst structure. This finding can help to build the comprehensive theory of nanotube growth and offers a prospect for chirality-preferential synthesis of carbon nanotubes by the exploitation of liquid catalyst droplets.

  4. Review on properties, dispersion and toxicology of carbon nanotubes

    International Nuclear Information System (INIS)

    Saeed, K.

    2010-01-01

    Carbon nanotubes (CNTs) have the most intensely studied nano structures because of their unique properties. There are two types of carbon nanotubes CNTs, single-walled carbon nanotubes (SWNTs) and multi-walled carbon nanotubes (MWNTs), prepared by chemical-vapour deposition (CVD), plasma enhanced chemical-vapour deposition, thermal chemical vapour deposition, Vapour phase growth, Arc discharge and Lasser ablation. Both single-walled carbon nanotubes (SWNTs) and multi-walled carbon nanotubes (MWNTs) possess high mechanical and electrical conductivity, ultra-light weight, high aspect ratio and have excellent chemical and thermal stabilities. They also possess semi- and metallic-conductive properties depending upon their chirality. This review focuses on progress toward functionalization (not only dispersed nano tube but also dramatically improve their solubility), preparation and purification, composites and the toxicity of the carbon nanotubes (CNTs). The functional groups attached to carbon nanotubes (CNTs) should react with polymers and improve the mechanical properties of the nano composites. Carbon nanotubes (CNTs) has significant application in pharmaceutical field such as drug delivery and nano medicine, but the available literature also suggests that carbon nanotubes (CNTs) may have unusual toxicity and have more adverse effects than the same mass of nano size carbon and quartz. (author)

  5. Lithium storage properties of multiwall carbon nanotubes prepared by CVD

    International Nuclear Information System (INIS)

    Ahn, J.-O.; Andong National University,; Wang, G.X.; Liu, H.K.; Dou, S.X.

    2003-01-01

    Full text: Multiwall carbon nanotubes (MWCNTs) were synthesised by chemical vapour deposition (CVD) method using acetylene gas. The XRD pattern of as prepared carbon nanotubes showed that the d 002 value is 3.44 Angstroms. The morphology and microstructure of carbon nanotubes were characterized by HRTEM. Most of carbon nanotubes are entangled together to form bundles or ropes. The diameter of the carbon nanotubes is in the range of 10 ∼ 20 nm. There is a small amount of amorphous carbon particles presented in the sample. However, the yield of carbon nanotubes is more than 95%. Electrochemical properties of carbon nanotubes were characterised via a variety of electrochemical testing techniques. The result of CV test showed that the Li insertion potential is quite low, which is very close to O V versus Li + /Li reference electrode, whereas the potential for Li de-intercalation is in the range of 0.2-0.4 V. There exists a slight voltage hysteresis between Li intercalation and Li de-intercalation, which is similar to the other carbonaceous materials. The intensity of redox peaks of carbon nanotubes decrease with scanning cycle, indicating that the reversible Li insertion capacity gradually decreases. The carbon nanotubes electrode demonstrated a reversible lithium storage capacity of 340 mAh/g with good cyclability at moderate current density. Further improvement of Li storage capacity is possible by opening the end of carbon nanotubes to allow lithium insertion into inner graphene sheet of carbon nanotubes. The kinetic properties of lithium insertion in carbon nanotube electrodes were characterised by a.c. impedance measurements. It was found that the lithium diffusion coefficient d Li decreases with an increase of Li ion concentration in carbon nanotube host

  6. 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.

  7. Energy structure of fullerenes and carbon nanotubes

    International Nuclear Information System (INIS)

    Byszewski, P.; Kowalska, E.

    1997-01-01

    The absorption spectrum of C 60 can be reasonably well reproduced theoretically with the use of the quantum chemistry calculation methods. It allows investigation of the influence of a deformation of C 60 on the absorption spectrum. The deformation of the electronic density on C 60 can occur under the influence of molecules of good solvent. Similar calculations of the energetic structure of carbon nanotubes does not support the idea that their chirality may strongly influence the energy levels distribution, in particular that it may open the energy gap of nanotubes. (author). 40 refs, 13 figs, 1 tab

  8. Aligned carbon nanotubes patterned photolithographically by silver

    Science.gov (United States)

    Huang, Shaoming; Mau, Albert H. W.

    2003-02-01

    Selective growth of aligned carbon nanotubes (CNTs) by pyrolysis of iron (II) phthalocyanine (FePc) on quartz substrate patterned photolithographically by metallic silver has been demonstrated. Micro/nanopattern of aligned CNTs can be achieved by using a photomask with features on a microscale. With convenient use of simple high-contract black and white films as a photomask, aligned nanotubes patterned with 20 μm resolution in large scale can be fabricated. This practical fabrication of aligned CNTs on patterned conducting substrate could be applied to various device applications of CNTs.

  9. Vertically aligned multiwalled carbon nanotubes as electronic interconnects

    Science.gov (United States)

    Gopee, Vimal Chandra

    The drive for miniaturisation of electronic circuits provides new materials challenges for the electronics industry. Indeed, the continued downscaling of transistor dimensions, described by Moore’s Law, has led to a race to find suitable replacements for current interconnect materials to replace copper. Carbon nanotubes have been studied as a suitable replacement for copper due to its superior electrical, thermal and mechanical properties. One of the advantages of using carbon nanotubes is their high current carrying capacity which has been demonstrated to be three orders of magnitude greater than that of copper. Most approaches in the implementation of carbon nanotubes have so far focused on the growth in vias which limits their application. In this work, a process is described for the transfer of carbon nanotubes to substrates allowing their use for more varied applications. Arrays of vertically aligned multiwalled carbon nanotubes were synthesised by photo-thermal chemical vapour deposition with high growth rates. Raman spectroscopy was used to show that the synthesised carbon nanotubes were of high quality. The carbon nanotubes were exposed to an oxygen plasma and the nature of the functional groups present was determined using X-ray photoelectron spectroscopy. Functional groups, such as carboxyl, carbonyl and hydroxyl groups, were found to be present on the surface of the multiwalled carbon nanotubes after the functionalisation process. The multiwalled carbon nanotubes were metallised after the functionalisation process using magnetron sputtering. Two materials, solder and sintered silver, were chosen to bind carbon nanotubes to substrates so as to enable their transfer and also to make electrical contact. The wettability of solder to carbon nanotubes was investigated and it was demonstrated that both functionalisation and metallisation were required in order for solder to bond with the carbon nanotubes. Similarly, functionalisation followed by metallisation

  10. 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.

  11. Occupational nanosafety considerations for carbon nanotubes and carbon nanofibers.

    Science.gov (United States)

    Castranova, Vincent; Schulte, Paul A; Zumwalde, Ralph D

    2013-03-19

    Carbon nanotubes (CNTs) are carbon atoms arranged in a crystalline graphene lattice with a tubular morphology. CNTs exhibit high tensile strength, possess unique electrical properties, are durable, and can be functionalized. These properties allow applications as structural materials, in electronics, as heating elements, in batteries, in the production of stain-resistant fabric, for bone grafting and dental implants, and for targeted drug delivery. Carbon nanofibers (CNFs) are strong, flexible fibers that are currently used to produce composite materials. Agitation can lead to aerosolized CNTs and CNFs, and peak airborne particulate concentrations are associated with workplace activities such as weighing, transferring, mixing, blending, or sonication. Most airborne CNTs or CNFs found in workplaces are loose agglomerates of micrometer diameter. However, due to their low density, they linger in workplace air for a considerable time, and a large fraction of these structures are respirable. In rat and mouse models, pulmonary exposure to single-walled carbon nanotubes (SWCNTs), multi-walled carbon nanotubes (MWCNTs), or CNFs causes the following pulmonary reactions: acute pulmonary inflammation and injury, rapid and persistent formation of granulomatous lesions at deposition sites of large CNT agglomerates, and rapid and progressive alveolar interstitial fibrosis at deposition sites of more dispersed CNT or CNF structures. Pulmonary exposure to SWCNTs can induce oxidant stress in aortic tissue and increases plaque formation in an atherosclerotic mouse model. Pulmonary exposure to MWCNTs depresses the ability of coronary arterioles to respond to dilators. These cardiovascular effects may result from neurogenic signals from sensory irritant receptors in the lung. Pulmonary exposure to MWCNTs also upregulates mRNA for inflammatory mediators in selected brain regions, and pulmonary exposure to SWCNTs upregulates the baroreceptor reflex. In addition, pulmonary exposure to

  12. 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.

  13. An in situ Raman spectroscopy study of stress transfer between carbon nanotubes and polymer

    International Nuclear Information System (INIS)

    Mu Minfang; Winey, Karen I; Osswald, Sebastian; Gogotsi, Yury

    2009-01-01

    The transfer mechanism of applied stress in single-wall carbon nanotube (SWCNT)/poly(methyl methacrylate) (PMMA) nanocomposites was investigated using in situ Raman spectroscopy on composite fibers. These SWCNT/PMMA nanocomposite fibers have no specific SWCNT-polymer interactions and the high degree of nanotube alignment minimizes the contributions from nanotube-nanotube interactions. Although tensile testing found significantly improved overall mechanical properties of the fibers, effective stress transfer to SWCNTs is limited to a small strain regime (ε<0.2%). At higher strains, the stress on the SWCNTs decreases due to the slippage at the nanotube-polymer interface. Slippage was also evident in scanning electron micrographs of fracture surfaces produced by tensile testing of the composite fibers. Above ε = 0.2%, the strain-induced slippage was accompanied by irreversible responses in stress and Raman peak shifts. This paper shows that efficient stress transfer to nanotubes as monitored by Raman spectroscopy is crucial to improving the mechanical properties of polymer nanocomposites and to detecting internal damage in nanocomposites.

  14. Adsorption characteristics of activated carbon hollow fibers

    Directory of Open Access Journals (Sweden)

    B. V. Kaludjerović

    2009-01-01

    Full Text Available Carbon hollow fibers were prepared with regenerated cellulose or polysulfone hollow fibers by chemical activation using sodium phosphate dibasic followed by the carbonization process. The activation process increases the adsorption properties of fibers which is more prominent for active carbone fibers obtained from the cellulose precursor. Chemical activation with sodium phosphate dibasic produces an active carbon material with both mesopores and micropores.

  15. Large quantity production of carbon and boron nitride nanotubes by mechano-thermal process

    International Nuclear Information System (INIS)

    Chen, Y.; Fitzgerald, J.D.; Chadderton, L.; Williams, J.S.; Campbell, S.J.

    2002-01-01

    Full text: Nanotube materials including carbon and boron nitride have excellent properties compared with bulk materials. The seamless graphene cylinders with a high length to diameter ratio make them as superstrong fibers. A high amount of hydrogen can be stored into nanotubes as future clean fuel source. Theses applications require large quantity of nanotubes materials. However, nanotube production in large quantity, fully controlled quality and low costs remains challenges for most popular synthesis methods such as arc discharge, laser heating and catalytic chemical decomposition. Discovery of new synthesis methods is still crucial for future industrial application. The new low-temperature mechano-thermal process discovered by the current author provides an opportunity to develop a commercial method for bulk production. This mechano-thermal process consists of a mechanical ball milling and a thermal annealing processes. Using this method, both carbon and boron nitride nanotubes were produced. I will present the mechano-thermal method as the new bulk production technique in the conference. The lecture will summarise main results obtained. In the case of carbon nanotubes, different nanosized structures including multi-walled nanotubes, nanocells, and nanoparticles have been produced in a graphite sample using a mechano-thermal process, consisting of I mechanical milling at room temperature for up to 150 hours and subsequent thermal annealing at 1400 deg C. Metal particles have played an important catalytic effect on the formation of different tubular structures. While defect structure of the milled graphite appears to be responsible for the formation of small tubes. It is found that the mechanical treatment of graphite powder produces a disordered and microporous structure, which provides nucleation sites for nanotubes as well as free carbon atoms. Multiwalled carbon nanotubes appear to grow via growth of the (002) layers during thermal annealing. In the case of BN

  16. 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.

  17. 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.

  18. 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.

  19. Electrochemically Powered, Energy-Conserving Carbon Nanotube Artificial Muscles.

    Science.gov (United States)

    Lee, Jae Ah; Li, Na; Haines, Carter S; Kim, Keon Jung; Lepró, Xavier; Ovalle-Robles, Raquel; Kim, Seon Jeong; Baughman, Ray H

    2017-08-01

    While artificial muscle yarns and fibers are potentially important for many applications, the combination of large strokes, high gravimetric work capacities, short cycle times, and high efficiencies are not realized for these fibers. This paper demonstrates here electrochemically powered carbon nanotube yarn muscles that provide tensile contraction as high as 16.5%, which is 12.7 times higher than previously obtained. These electrochemical muscles can deliver a contractile energy conversion efficiency of 5.4%, which is 4.1 times higher than reported for any organic-material-based artificial muscle. All-solid-state parallel muscles and braided muscles, which do not require a liquid electrolyte, provide tensile contractions of 11.6% and 5%, respectively. These artificial muscles might eventually be deployed for a host of applications, from robotics to perhaps even implantable medical devices. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  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. Carbon nanotubes and graphene in analytical sciences

    International Nuclear Information System (INIS)

    Perez-Lopez, B.; Merkoci, A.

    2012-01-01

    Nanosized carbon materials are offering great opportunities in various areas of nanotechnology. Carbon nanotubes and graphene, due to their unique mechanical, electronic, chemical, optical and electrochemical properties, represent the most interesting building blocks in various applications where analytical chemistry is of special importance. The possibility of conjugating carbon nanomaterials with biomolecules has received particular attention with respect to the design of chemical sensors and biosensors. This review describes the trends in this field as reported in the last 6 years in (bio)analytical chemistry in general, and in biosensing in particular. (author)

  2. Carbon nanotube formation by laser direct writing

    International Nuclear Information System (INIS)

    Wu, Y.-T.; Su, H.-C.; Tsai, C.-M.; Liu, K.-L.; Chen, G.-D.; Huang, R.-H.; Yew, T.-R.

    2008-01-01

    This letter presents carbon nanotube (CNT) formation by laser direct writing using 248 nm KrF excimer pulsed laser in air at room temperature, which was applied to irradiate amorphous carbon (a-C) assisted by Ni catalysts underneath for the transformation of carbon species into CNTs. The CNTs were synthesized under appropriate combination of laser energy density and a-C thickness. The growth mechanism and key parameters to determine the success of CNT formation were also discussed. The demonstration of the CNT growth by laser direct writing in air at room temperature opens an opportunity of in-position CNT formation at low temperatures

  3. Remote Joule heating by a carbon nanotube.

    Science.gov (United States)

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

    2012-04-08

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

  4. Graphene nanoribbons production from flat carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-11-14

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

  5. Graphene nanoribbons production from flat carbon nanotubes

    International Nuclear Information System (INIS)

    Melo, W. S.; Guerini, S.; Diniz, E. M.

    2015-01-01

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

  6. Carbon nanotube based stationary phases for microchip chromatography

    DEFF Research Database (Denmark)

    Mogensen, Klaus Bo; Kutter, Jörg Peter

    2012-01-01

    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......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...... 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...

  7. The Mossbauer spectra of carbon nanotubes synthesize using ferrite catalyst

    International Nuclear Information System (INIS)

    Zhang Haiyan; Lin Jiapeng; Peng Zuxiong; Zeng Guoxun; Pang Jinshan; Chen Yiming

    2009-01-01

    The ferrite powder with honeycombed structure obtained by chemical combustion was used as catalyst to synthesize multi-walled carbon nanotubes by chemical vapor deposition. The magnetic components and characters of the the carbon nanotubes synthesized were investigated by X-ray diffraction (XRD), Mossbauer spectra and vibrating-sample magnetometer (VSM). The ferric components of the carbon nanotubes samples can be identified by Mossbauer spectra. The Mossbauer spectra of carbon nanotubes sample after purification contains two ferromagnetic sextet components corresponding to α-Fe species and Fe 3 C (cementite) species. While the Mossbauer spectra of the carbon nanotubes sample before purification contains three ferromagnetic sextet components corresponding to α-Fe species, Fe 3 C species and γ-Fe 2 O 3 . The saturation magnetization intensity Ms of carbon nanotubes sample after purification is decreased from 46.61 to 2.94 emu/g, but the coercive force increasd and reached 328Oe.

  8. Electrophoretic deposition and field emission properties of patterned carbon nanotubes

    International Nuclear Information System (INIS)

    Zhao Haifeng; Song Hang; Li Zhiming; Yuan Guang; Jin Yixin

    2005-01-01

    Patterned carbon nanotubes on silicon substrates were obtained using electrophoretic method. The carbon nanotubes migrated towards the patterned silicon electrode in the electrophoresis suspension under the applied voltage. The carbon nanotubes arrays adhered well on the silicon substrates. The surface images of carbon nanotubes were observed by scanning electron microscopy. The field emission properties of the patterned carbon nanotubes were tested in a diode structure under a vacuum pressure below 5 x 10 -4 Pa. The measured emission area was about 1.0 mm 2 . The emission current density up to 30 mA/cm 2 at an electric field of 8 V/μm has been obtained. The deposition of patterned carbon nanotubes by electrophoresis is an alternative method to prepare field emission arrays

  9. Ag-catalysed cutting of multi-walled carbon nanotubes

    International Nuclear Information System (INIS)

    La Torre, A; Rance, G A; Miners, S A; Lucas, C Herreros; Smith, E F; Giménez-López, M C; Khlobystov, A N; Fay, M W; Brown, P D; Zoberbier, T; Kaiser, U

    2016-01-01

    In this work, the cutting of carbon nanotubes is investigated using silver nanoparticles deposited on arc discharge multi-walled carbon nanotubes. The composite is subsequently heated in air to fabricate shortened multi-walled nanotubes. Complementary transmission electron microscopy and spectroscopy techniques shed light on the cutting mechanism. The nanotube cutting is catalysed by the fundamental mechanism based on the coordination of the silver atoms to the π-bonds of carbon nanotubes. As a result of the metal coordination, the strength of the carbon–carbon bond is reduced, promoting the oxidation of carbon at lower temperature when heated in air, or lowering the activation energy required for the removal of carbon atoms by electron beam irradiation, assuring in both cases the cutting of the nanotubes. (paper)

  10. The conversion of polyaniline nanotubes to nitrogen-containing carbon nanotubes and their comparison with multi-walled carbon nanotubes

    Czech Academy of Sciences Publication Activity Database

    Trchová, Miroslava; Konyushenko, Elena; Stejskal, Jaroslav; Kovářová, Jana; Ciric-Marjanovic, G.

    2009-01-01

    Roč. 94, č. 6 (2009), s. 929-938 ISSN 0141-3910 R&D Projects: GA ČR GA203/08/0686; GA AV ČR IAA400500905 Institutional research plan: CEZ:AV0Z40500505 Keywords : carbon nanotubes * carbonization * FTIR spectroscopy Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.154, year: 2009

  11. Process for derivatizing carbon nanotubes with diazonium species

    Science.gov (United States)

    Tour, James M. (Inventor); Bahr, Jeffrey L. (Inventor); Yang, Jiping (Inventor)

    2007-01-01

    The invention incorporates new processes for the chemical modification of carbon nanotubes. Such processes involve the derivatization of multi- and single-wall carbon nanotubes, including small diameter (ca. 0.7 nm) single-wall carbon nanotubes, with diazonium species. The method allows the chemical attachment of a variety of organic compounds to the side and ends of carbon nanotubes. These chemically modified nanotubes have applications in polymer composite materials, molecular electronic applications and sensor devices. The methods of derivatization include electrochemical induced reactions thermally induced reactions (via in-situ generation of diazonium compounds or pre-formed diazonium compounds), and photochemically induced reactions. The derivatization causes significant changes in the spectroscopic properties of the nanotubes. The estimated degree of functionality is ca. 1 out of every 20 to 30 carbons in a nanotube bearing a functionality moiety. Such electrochemical reduction processes can be adapted to apply site-selective chemical functionalization of nanotubes. Moreover, when modified with suitable chemical groups, the derivatized nanotubes are chemically compatible with a polymer matrix, allowing transfer of the properties of the nanotubes (such as, mechanical strength or electrical conductivity) to the properties of the composite material as a whole. Furthermore, when modified with suitable chemical groups, the groups can be polymerized to form a polymer that includes carbon nanotubes ##STR00001##.

  12. Oscillation of nested fullerenes (carbon onions) in carbon nanotubes

    International Nuclear Information System (INIS)

    Thamwattana, Ngamta; Hill, James M.

    2008-01-01

    Nested spherical fullerenes, which are sometimes referred to as carbon onions, of I h symmetries which have N(n) carbon atoms in the nth shell given by N(n) = 60n 2 are studied in this paper. The continuum approximation together with the Lennard-Jones potential is utilized to determine the resultant potential energy. High frequency nanoscale oscillators or gigahertz oscillators created from fullerenes and both single- and multi-walled carbon nanotubes have attracted much attention for a number of proposed applications, such as ultra-fast optical filters and ultra-sensitive nano-antennae that might impact on the development of computing and signalling nano-devices. Further, it is only at the nanoscale where such gigahertz frequencies can be achieved. This paper focuses on the interaction of nested fullerenes and the mechanics of such molecules oscillating in carbon nanotubes. Here we investigate such issues as the acceptance condition for nested fullerenes into carbon nanotubes, the total force and energy of the nested fullerenes, and the velocity and gigahertz frequency of the oscillating molecule. In particular, optimum nanotube radii are determined for which nested fullerenes oscillate at maximum velocity and frequency, which will be of considerable benefit for the design of future nano-oscillating devices

  13. 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.

  14. Continuous Growth of Vertically Aligned Carbon Nanotubes Forests

    OpenAIRE

    Guzman de Villoria, Roberto; Wardle, Brian L.

    2011-01-01

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

  15. Chemically Functionalized Carbon Nanotubes as Substrates for Neuronal Growth

    Science.gov (United States)

    Hu, Hui; Ni, Yingchun; Montana, Vedrana; Haddon, Robert C.; Parpura, Vladimir

    2009-01-01

    We report the use of chemically modified carbon nanotubes as a substrate for cultured neurons. The morphological features of neurons that directly reflect their potential capability in synaptic transmission are characterized. The chemical properties of carbon nanotubes are systematically varied by attaching different functional groups that confer known characteristics to the substrate. By manipulating the charge carried by functionalized carbon nanotubes we are able to control the outgrowth and branching pattern of neuronal processes. PMID:21394241

  16. 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.

  17. 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.

  18. Molecular discriminators using single wall carbon nanotubes

    International Nuclear Information System (INIS)

    Bhattacharyya, Tamoghna; Dasgupta, Anjan Kr; Ray, Nihar Ranjan; Sarkar, Sabyasachi

    2012-01-01

    The interaction between single wall carbon nanotubes (SWNTs) and amphiphilic molecules has been studied in a solid phase. SWNTs are allowed to interact with different amphiphilic probes (e.g. lipids) in a narrow capillary interface. Contact between strong hydrophobic and amphiphilic interfaces leads to a molecular restructuring of the lipids at the interface. The geometry of the diffusion front and the rate and the extent of diffusion of the interface are dependent on the structure of the lipid at the interface. Lecithin having a linear tail showed greater mobility of the interface as compared to a branched tail lipid like dipalmitoyl phosphatidylcholine, indicating the hydrophobic interaction between single wall carbon nanotube core and the hydrophobic tail of the lipid. Solid phase interactions between SWNT and lipids can thus become a very simple but efficient means of discriminating amphiphilic molecules in general and lipids in particular. (paper)

  19. 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

  20. 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…

  1. Synthesis of PbI(2) single-layered inorganic nanotubes encapsulated within carbon nanotubes.

    Science.gov (United States)

    Cabana, Laura; Ballesteros, Belén; Batista, Eudar; Magén, César; Arenal, Raúl; Oró-Solé, Judith; Rurali, Riccardo; Tobias, Gerard

    2014-04-02

    The template assisted growth of single-layered inorganic nanotubes is reported. Single-crystalline lead iodide single-layered nanotubes have been prepared using the inner cavities of carbon nanotubes as hosting templates. The diameter of the resulting inorganic nanotubes is merely dependent on the diameter of the host. This facile method is highly versatile opening up new horizons in the preparation of single-layered nanostructures. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Carbon Nanotubes as Future Energy Storage System

    OpenAIRE

    Vasu , V; Silambarasan , D

    2017-01-01

    International audience; Hydrogen is considered to be a clean energy carrier. At present the main drawback in using hydrogen as the fuel is the lack of proper hydrogen storage vehicle, thus ongoing research is focused on the development of advance hydrogen storage materials. Many alloys are able to store hydrogen reversibly, but the gravimetric storage density is too low for any practical applications. Theoretical studies have predicted that interaction of hydrogen with carbon nanotubes is by ...

  3. 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.

  4. Passive Mode Carbon Nanotube Underwater Acoustic Transducer

    Science.gov (United States)

    2016-09-20

    Acoustical transducer arrays can reflect a sound signal in reverse to the sender which can be used for echo location devices. [0008] In Jiang...States Patent No. 8,494,187) a sound wave generator is disclosed which includes a carbon nanotube structure and an insulating reinforcement structure... acoustic device that includes an electrode layer and a sound wave generator. The sound wave generator is disposed on a surface of the electrode

  5. Carbon nanotubes: do they toughen brittle matrices?

    Czech Academy of Sciences Publication Activity Database

    Chao, J.; Inam, F.; Reece, M.J.; Chlup, Zdeněk; Dlouhý, Ivo; Shaffer, M.S.P.; Boccaccini, A. R.

    2011-01-01

    Roč. 46, č. 14 (2011), s. 4770-4779 ISSN 0022-2461 R&D Projects: GA ČR GA101/09/1821 Institutional research plan: CEZ:AV0Z20410507 Keywords : fracture toughness * carbon nanotube * silica glass Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 2.015, year: 2011 http://www.springerlink.com/content/74106l0458326n91/

  6. Carbon nanotube-based black coatings

    Science.gov (United States)

    Lehman, J.; Yung, C.; Tomlin, N.; Conklin, D.; Stephens, M.

    2018-03-01

    Coatings comprising carbon nanotubes are very black, that is, characterized by uniformly low reflectance over a broad range of wavelengths from the visible to far infrared. Arguably, there is no other material that is comparable. This is attributable to the intrinsic properties of graphitic material as well as the morphology (density, thickness, disorder, and tube size). We briefly describe a history of other coatings such as nickel phosphorous, gold black, and carbon-based paints and the comparable structural morphology that we associate with very black coatings. The need for black coatings is persistent for a variety of applications ranging from baffles and traps to blackbodies and thermal detectors. Applications for space-based instruments are of interest and we present a review of space qualification and the results of outgassing measurements. Questions of nanoparticle safety depend on the nanotube size and aspect ratio as well as the nature and route of exposure. We describe the growth of carbon nanotube forests along with the catalyst requirements and temperature limitations. We also describe coatings derived from carbon nanotubes and applied like paint. Building the measurement apparatus and determining the optical properties of something having negligible reflectance are challenging and we summarize the methods and means for such measurements. There exists information in the literature for effective media approximations to model the dielectric function of vertically aligned arrays. We summarize this along with the refractive index of graphite from the literature that is necessary for modeling the optical properties. In our experience, the scientific questions can be overshadowed by practical matters, so we provide an appendix of recipes for making as-grown and sprayed coatings along with an example of reflectance measurements.

  7. New Insight into Carbon Nanotube Electronic Structure Selectivity

    Energy Technology Data Exchange (ETDEWEB)

    Sumpter, Bobby G [ORNL; Meunier, Vincent [ORNL; Jiang, Deen [ORNL

    2009-01-01

    The fundamental role of aryl diazonium salts for post synthesis selectivity of carbon nanotubes is investigated using extensive electronic structure calculations. The resulting understanding for diazonium salt based selective separation of conducting and semiconducting carbon nanotubes shows how the primary contributions come from the interplay between the intrinsic electronic structure of the carbon nanotubes and that of the anion of the salt. We demonstrate how the electronic transport properties change upon the formation of charge transfer complexes and upon their conversion into covalently attached functional groups. Our results are found to correlate well with experiments and provide for the first time an atomistic description for diazonium salt based chemical separation of carbon nanotubes

  8. Conformational changes of fibrinogen in dispersed carbon nanotubes

    Directory of Open Access Journals (Sweden)

    Park SJ

    2012-08-01

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

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

    Science.gov (United States)

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

    2016-03-30

    Owing to their unique and interesting properties, extensive research round the globe has been carried out on carbon nanotubes and carbon nanotubes based systems to investigate their practical usefulness in biomedical applications. The results from these studies demonstrate a great promise in their use in targeted drug delivery systems, diagnostic techniques and in bio-analytical applications. Although, carbon nanotubes possess quite interesting properties, which make them potential candidates in the biomedical science, but they also have some inherent properties which arise great concern regarding their biosafety. In this comprehensive review, we have discussed different aspects of carbon nanotubes and carbon nanotube based systems related to biomedical applications. In the beginning, a short historical account of these tiny yet powerful particles is given followed by discussion regarding their types, properties, methods of synthesis, large scale production method, purification techniques and characterization aspects of carbon nanotubes. In the second part of the review, the functionalization of carbon nanotubes is reviewed in detail, which is not only important to make them biocompatible and stable in biological systems but also render them a great property of loading various biomolecules, diagnostic and therapeutic moieties resulting in diversified applications. In the final part of the review, emphasis is given on the pharmacokinetic aspects of carbon nanotubes including administration routes, absorption mechanisms, distribution and elimination of carbon nanotubes based systems. Lastly, a comprehensive account about the potential biomedical applications has been given followed by insights into the future. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Simulation of the Band Structure of Graphene and Carbon Nanotube

    International Nuclear Information System (INIS)

    Mina, Aziz N; Awadallah, Attia A; Ahmed, Riham R; Phillips, Adel H

    2012-01-01

    Simulation technique has been performed to simulate the band structure of both graphene and carbon nanotube. Accordingly, the dispersion relations for graphene and carbon nanotube are deduced analytically, using the tight binding model and LCAO scheme. The results from the simulation of the dispersion relation of both graphene and carbon nanotube were found to be consistent with those in the literature which indicates the correctness of the process of simulation technique. The present research is very important for tailoring graphene and carbon nanotube with specific band structure, in order to satisfy the required electronic properties of them.

  11. 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.

  12. 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.

  13. Preparation of carbon nanotubes by MPECVD

    International Nuclear Information System (INIS)

    El-Shazly Duraia, M.A.; Mansorov, Z.A.; Tokmoldin, S.Zh.; Klimenov, V.V.; Nevmerzhitsky, I.S.; Dochshanov, A.M.

    2009-01-01

    Microwave plasma-enhanced chemical vapor deposition (MPECVD) method has been regarded as one of the most promising candidates for the synthesis of CNTs due to the vertical alignment, the large area growth, the lower growth temperature, uniform heat distribution and the good control of the different growth parameters. In this work we present our results about the preparation of carbon nanotube with different morphologies by using microwave plasma enhanced chemical vapor deposition MPECVD. Well aligned, curly and coiled carbon nanotubes have been prepared. We have investigated the effect of the different growth condition parameters such as type of the catalyst, pressure and the hydrogen to methane flow rate ratio on the morphology of the carbon nanotubes. The results were showed that there is a great dependence of the morphology of carbon nanotubes on these parameters. There is a linear relation between the growth rate and the methane to hydrogen ratio. We found that the growth rate has a great dependence on the amount of methane. For example the growth rate varied from the value 1,34 μm/min when the methane flow rate was 10 sccm to more than 14 μm/min when the methane flow rate was raised to 50 sccm. This growth rate is greater than that reported in the literature. The effect of the gas pressure on the CNTs was also studied. The Raman spectra (excitation wavelength 473 nm) of all samples show D-band peak at around 1300 cm -1 and G-band peak at around 1580 cm -1 , which indicate that our CNTs are multi wall CNTs (MWCNTs). The D-band and the G-band correspond to sp 2 and sp 3 carbon stretching modes relatively, and their intensity ratio is a measure of the amount of disorder in the CNTs. The D-band is known to be attributed to the carbonaceous particles, defects in the curved graphitic sheet and tube ends. It has been suggested that lower I g /I d ratios and narrower first and second order D and G bands are suggestive of well-aligned NNTs. The photoluminescence PL

  14. 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 ...

  15. Magneto-carbonization method for production of carbon fiber, and high performance carbon fibers made thereby

    Science.gov (United States)

    Naskar, Amit K.; Ozcan, Soydan; Eberle, Claude C.; Abdallah, Mohamed Gabr; Mackiewicz, Ludtka Gail; Ludtka, Gerard Michael; Paulauskas, Felix Leonard; Rivard, John Daniel Kennedy

    2017-08-08

    Method for the preparation of carbon fiber from fiber precursor, wherein the fiber precursor is subjected to a magnetic field of at least 3 Tesla during a carbonization process. The carbonization process is generally conducted at a temperature of at least 400.degree. C. and less than 2200.degree. C., wherein, in particular embodiments, the carbonization process includes a low temperature carbonization step conducted at a temperature of at least or above 400.degree. C. or 500.degree. C. and less than or up to 1000.degree. C., 1100.degree. C., or 1200.degree. C., followed by a high temperature carbonization step conducted at a temperature of at least or above 1200.degree. C. In particular embodiments, particularly in the case of a polyacrylonitrile (PAN) fiber precursor, the resulting carbon fiber may possess a minimum tensile strength of at least 600 ksi, a tensile modulus of at least 30 Msi, and an ultimate elongation of at least 1.5%.

  16. Carbon nanotube network-silicon oxide non-volatile switches.

    Science.gov (United States)

    Liao, Albert D; Araujo, Paulo T; Xu, Runjie; Dresselhaus, Mildred S

    2014-12-08

    The integration of carbon nanotubes with silicon is important for their incorporation into next-generation nano-electronics. Here we demonstrate a non-volatile switch that utilizes carbon nanotube networks to electrically contact a conductive nanocrystal silicon filament in silicon dioxide. We form this device by biasing a nanotube network until it physically breaks in vacuum, creating the conductive silicon filament connected across a small nano-gap. From Raman spectroscopy, we observe coalescence of nanotubes during breakdown, which stabilizes the system to form very small gaps in the network~15 nm. We report that carbon nanotubes themselves are involved in switching the device to a high resistive state. Calculations reveal that this switching event occurs at ~600 °C, the temperature associated with the oxidation of nanotubes. Therefore, we propose that, in switching to a resistive state, the nanotube oxidizes by extracting oxygen from the substrate.

  17. Preparation of carbon nanotubes from vacuum pyrolysis of polycarbosilane

    International Nuclear Information System (INIS)

    Jou, S.; Hsu, C.K.

    2004-01-01

    Carbon nanotubes (CNTs) were synthesized by vacuum pyrolysis of two types of polycarbosilane (PCS) with iron nano-particles between 800 and 1100 deg. C. Straight nanotubes were obtained from low molecular weight (990 g/mol) PCS whereas curled nanotubes were derived from medium molecular weight (1290 g/mol) PCS. Diameters of these straight and curled nanotubes were between 5 and 20 nm. The mechansim of condensed phase growth of carbon nanotubes was discussed. Electron emission capability of these carbon nanotubes increased with their pyrolyzing temperature. The electric fields required to emit a current density of 10 -2 A/cm 2 from the straight nanotubes being pyrolyzed at 800, 900, 1000, and 1100 deg. C were 1.17, 0.73, 0.67, and 0.33 V/μm, respectively

  18. Efficient electrochemical degradation of multiwall carbon nanotubes.

    Science.gov (United States)

    Reipa, Vytas; Hanna, Shannon K; Urbas, Aaron; Sander, Lane; Elliott, John; Conny, Joseph; Petersen, Elijah J

    2018-07-15

    As the production mass of multiwall carbon nanotubes (MWCNT) increases, the potential for human and environmental exposure to MWCNTs may also increase. We have shown that exposing an aqueous suspension of pristine MWCNTs to an intense oxidative treatment in an electrochemical reactor, equipped with an efficient hydroxyl radical generating Boron Doped Diamond (BDD) anode, leads to their almost complete mineralization. Thermal optical transmittance analysis showed a total carbon mass loss of over two orders of magnitude due to the electrochemical treatment, a result consistent with measurements of the degraded MWCNT suspensions using UV-vis absorbance. Liquid chromatography data excludes substantial accumulation of the low molecular weight reaction products. Therefore, up to 99% of the initially suspended MWCNT mass is completely mineralized into gaseous products such as CO 2 and volatile organic carbon. Scanning electron microscopy (SEM) images show sporadic opaque carbon clusters suggesting the remaining nanotubes are transformed into structure-less carbon during their electrochemical mineralization. Environmental toxicity of pristine and degraded MWCNTs was assessed using Caenorhabditis elegans nematodes and revealed a major reduction in the MWCNT toxicity after treatment in the electrochemical flow-by reactor. Published by Elsevier B.V.

  19. Interfacial Studies of Sized Carbon Fiber

    International Nuclear Information System (INIS)

    Shahrul, S. N.; Hartini, M. N.; Hilmi, E. A.; Nizam, A.

    2010-01-01

    This study was performed to investigate the influence of sizing treatment on carbon fiber in respect of interfacial adhesion in composite materials, Epolam registered 2025. Fortafil unsized carbon fiber was used to performed the experiment. The fiber was commercially surface treated and it was a polyacrylonitrile based carbon fiber with 3000 filament per strand. Epicure registered 3370 was used as basic sizing chemical and dissolved in two types of solvent, ethanol and acetone for the comparison purpose. The single pull out test has been used to determine the influence of sizing on carbon fiber. The morphology of carbon fiber was observed by atomic force microscopy (AFM) and scanning electron microscopy (SEM). The apparent interfacial strength IFSS values determined by pull out test for the Epicure registered 3370/ethanol sized carbon fiber pointed to a good interfacial behaviour compared to the Epicure registered 3370/acetone sized carbon fiber. The Epicure registered 3370/ethanol sizing agent was found to be effective in promoting adhesion because of the chemical reactions between the sizing and Epolam registered 2025 during the curing process. From this work, it showed that sized carbon fiber using Epicure registered 3370 with addition of ethanol give higher mechanical properties of carbon fiber in terms of shear strength and also provided a good adhesion between fiber and matrix compared to the sizing chemical that contain acetone as a solvent.

  20. Imaging active topological defects in carbon nanotubes

    Science.gov (United States)

    Suenaga, Kazu; Wakabayashi, Hideaki; Koshino, Masanori; Sato, Yuta; Urita, Koki; Iijima, Sumio

    2007-06-01

    A single-walled carbon nanotube (SWNT) is a wrapped single graphene layer, and its plastic deformation should require active topological defects-non-hexagonal carbon rings that can migrate along the nanotube wall. Although in situ transmission electron microscopy (TEM) has been used to examine the deformation of SWNTs, these studies deal only with diameter changes and no atomistic mechanism has been elucidated experimentally. Theory predicts that some topological defects can form through the Stone-Wales transformation in SWNTs under tension at 2,000 K, and could act as a dislocation core. We demonstrate here, by means of high-resolution (HR)-TEM with atomic sensitivity, the first direct imaging of pentagon-heptagon pair defects found in an SWNT that was heated at 2,273 K. Moreover, our in situ HR-TEM observation reveals an accumulation of topological defects near the kink of a deformed nanotube. This result suggests that dislocation motions or active topological defects are indeed responsible for the plastic deformation of SWNTs.

  1. Properties of single-walled carbon nanotube-based aerogels as a function of nanotube loading

    International Nuclear Information System (INIS)

    Worsley, Marcus A.; Pauzauskie, Peter J.; Kucheyev, Sergei O.; Zaug, Joseph M.; Hamza, Alex V.; Satcher, Joe H.; Baumann, Theodore F.

    2009-01-01

    Here, we present the synthesis and characterization of low-density single-walled carbon nanotube-based aerogels (SWNT-CA). Aerogels with varying nanotube loading (0-55 wt.%) and density (20-350 mg cm -3 ) were fabricated and characterized by four-probe method, electron microscopy, Raman spectroscopy and nitrogen porosimetry. Several properties of the SWNT-CAs were highly dependent upon nanotube loading. At nanotube loadings of 55 wt.%, shrinkage of the aerogel monoliths during carbonization and drying was almost completely eliminated. Electrical conductivities are improved by an order of magnitude for the SWNT-CA (55 wt.% nanotubes) compared to those of foams without nanotubes. Surface areas as high as 184 m 2 g -1 were achieved for SWNT-CAs with greater than 20 wt.% nanotube loading.

  2. Carbon fiber manufacturing via plasma technology

    Science.gov (United States)

    Paulauskas, Felix L.; Yarborough, Kenneth D.; Meek, Thomas T.

    2002-01-01

    The disclosed invention introduces a novel method of manufacturing carbon and/or graphite fibers that avoids the high costs associated with conventional carbonization processes. The method of the present invention avoids these costs by utilizing plasma technology in connection with electromagnetic radiation to produce carbon and/or graphite fibers from fully or partially stabilized carbon fiber precursors. In general, the stabilized or partially stabilized carbon fiber precursors are placed under slight tension, in an oxygen-free atmosphere, and carbonized using a plasma and electromagnetic radiation having a power input which is increased as the fibers become more carbonized and progress towards a final carbon or graphite product. In an additional step, the final carbon or graphite product may be surface treated with an oxygen-plasma treatment to enhance adhesion to matrix materials.

  3. Carbon nanotube substrates and catalyzed hot stamp for polishing and patterning the substrates

    Science.gov (United States)

    Wang, Yuhuang [Evanston, IL; Hauge, Robert H [Houston, TX; Schmidt, Howard K [Houston, TX; Kim, Myung Jong [Houston, TX; Kittrell, W Carter [Houston, TX

    2009-09-08

    The present invention is generally directed to catalyzed hot stamp methods for polishing and/or patterning carbon nanotube-containing substrates. In some embodiments, the substrate, as a carbon nanotube fiber end, is brought into contact with a hot stamp (typically at 200-800.degree. C.), and is kept in contact with the hot stamp until the morphology/patterns on the hot stamp have been transferred to the substrate. In some embodiments, the hot stamp is made of material comprising one or more transition metals (Fe, Ni, Co, Pt, Ag, Au, etc.), which can catalyze the etching reaction of carbon with H.sub.2, CO.sub.2, H.sub.2O, and/or O.sub.2. Such methods can (1) polish the carbon nanotube-containing substrate with a microscopically smooth finish, and/or (2) transfer pre-defined patterns from the hot stamp to the substrate. Such polished or patterned carbon nanotube substrates can find application as carbon nanotube electrodes, field emitters, and field emitter arrays for displays and electron sources.

  4. Low-frequency plasmons in metallic carbon nanotubes

    International Nuclear Information System (INIS)

    Lin, M.F.; Chuu, D.S.; Shung, K.W.

    1997-01-01

    A metallic carbon nanotube could exhibit a low-frequency plasmon, while a semiconducting carbon nanotube or a graphite layer could not. This plasmon is due to the free carriers in the linear subbands intersecting at the Fermi level. The low-frequency plasmon, which corresponds to the vanishing transferred angular momentum, belongs to an acoustic plasmon. For a smaller metallic nanotube, it could exist at larger transferred momenta, and its frequency is higher. Such a plasmon behaves as that in a one-dimensional electron gas (EGS). However, it is very different from the π plasmons in all carbon nanotubes. Intertube Coulomb interactions in a metallic multishell nanotube and a metallic nanotube bundle have been included. They have a strong effect on the low-frequency plasmon. The intertube coupling among coaxial nanotubes markedly modifies the acoustic plasmons in separate metallic nanotubes. When metallic carbon nanotubes are packed in the bundle form, the low-frequency plasmon would change into an optical plasmon, and behave like that in a three-dimensional EGS. Experimental measurements could be used to distinguish metallic and semiconducting carbon nanotubes. copyright 1997 The American Physical Society

  5. Fullerenes, nanotubes, onions and related carbon structures

    Energy Technology Data Exchange (ETDEWEB)

    Rao, C N.R.; Seshadri, Ram; Govindaraj, A; Sen, Rahul [Solid State and Structural Chemistry Unit, CSIR Centre of Excellence in Chemistry and Materials Research Centre, Indian Institute of Science, Bangalore (India)

    1995-12-01

    Fullerenes, containing five- and six-membered carbon rings, of which C{sub 6}0 and C{sub 7}0 are the prominent members, exhibit phase transitions associated with orientational ordering. When C{sub 6}0 is suitably doped with electrons, it shows novel superconducting and magnetic properties. We review these and other properties of fullerenes in bulk or in film form along with the preparative and structural aspects. Carbon nanotubes and onions (hyperfullerenes) are the other forms of carbon whose material properties have aroused considerable interest. Besides discussing these new forms of carbon, we briefly introduce other possible forms, such as those involving five-, six- and seven-membered rings and hybrids between diamond and graphite

  6. Magnetic properties of carbon nanotubes with and without catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Lipert, Kamil; Ritschel, Manfred; Leonhardt, Albrecht; Krupskaya, Yulia; Buechner, Bernd; Klingeler, Ruediger, E-mail: k.lipert@ifw-dresden.d [Leibniz Institute for Solid State and Materials Research (IFW) Dresden (Germany)

    2010-01-01

    In this paper we report on the magnetic properties of single- and multiwalled carbon nanotubes synthesized using different chemical vapour deposition methods and with variety of catalyst materials (ferromagnetic Fe, FeCo and diamagnetic Re). Different methods yield carbon nanotubes with different morphologies and different quantity of residual catalyst material. Catalyst particles are usually encapsulated in the nanotubes and influence the magnetic respond of the samples. Varying ferromagnetic properties depending on the shape, size and type of catalyst are discussed in detail. The data are compared with M(H) characteristics of carbon nanotubes without catalysts and with nonmagnetic rhenium, as a reference.

  7. Spinning, structure and properties of PP/CNTs and PP/carbon black composite fibers

    Science.gov (United States)

    Marcincin, A.; Hricova, M.; Ujhelyiova, A.

    2014-08-01

    In this paper, the effect of the compatibilisers-dispersants and other nanofillers on melt spinning of the polypropylene (PP) composites, containing carbon nanotubes (CNTs), and carbon black pigment (CBP) has been investigated. Further, the structure and selected properties of composite fibers, such as mechanical and electrical have been studied. The results revealed, that percolation threshold for PP/CBP composite fibres was situated within the concentration of 15 - 20 wt%, what is several times higher than for PP/CNTs fibers.

  8. A carbon nanotube-based pressure sensor

    International Nuclear Information System (INIS)

    Karimov, Kh S; Saleem, M; Khan, Adam; Qasuria, T A; Mateen, A; Karieva, Z M

    2011-01-01

    In this study, a carbon nanotube (CNT)-based Al/CNT/Al pressure sensor was designed, fabricated and investigated. The sensor was fabricated by depositing CNTs on an adhesive elastic polymer tape and placing this in an elastic casing. The diameter of multiwalled nanotubes varied between 10 and 30 nm. The nominal thickness of the CNT layers in the sensors was in the range ∼300-430 μm. The inter-electrode distance (length) and the width of the surface-type sensors were in the ranges 4-6 and 3-4 mm, respectively. The dc resistance of the sensors decreased 3-4 times as the pressure was increased up to 17 kN m -2 . The resistance-pressure relationships were simulated.

  9. A carbon nanotube immunosensor for Salmonella

    Science.gov (United States)

    Lerner, Mitchell B.; Goldsmith, Brett R.; McMillon, Ronald; Dailey, Jennifer; Pillai, Shreekumar; Singh, Shree R.; Johnson, A. T. Charlie

    2011-12-01

    Antibody-functionalized carbon nanotube devices have been suggested for use as bacterial detectors for monitoring of food purity in transit from the farm to the kitchen. Here we report progress towards that goal by demonstrating specific detection of Salmonella in complex nutrient broth solutions using nanotube transistors functionalized with covalently-bound anti-Salmonella antibodies. The small size of the active device region makes them compatible with integration in large-scale arrays. We find that the on-state current of the transistor is sensitive specifically to the Salmonella concentration and saturates at low concentration (Salmonella and other bacteria types, with no sign of saturation even at much larger concentrations (108 cfu/ml).

  10. Modeling of a carbon nanotube ultracapacitor.

    Science.gov (United States)

    Orphanou, Antonis; Yamada, Toshishige; Yang, Cary Y

    2012-03-09

    The modeling of carbon nanotube ultracapacitor (CNU) performance based on the simulation of electrolyte ion motion between the cathode and the anode is described. Using a molecular dynamics (MD) approach, the equilibrium positions of the electrode charges interacting through the Coulomb potential are determined, which in turn yield the equipotential surface and electric field associated with the capacitor. With an applied ac voltage, the current is computed based on the nanotube and electrolyte particle distribution and interaction, resulting in the frequency-dependent impedance Z(ω). From the current and impedance profiles, the Nyquist and cyclic voltammetry (CV) plots are then extracted. The results of these calculations compare well with existing experimental data. A lumped-element equivalent circuit for the CNU is proposed and the impedance computed from this circuit correlates well with the simulated and measured impedances.

  11. Batch fabrication of carbon nanotube bearings

    International Nuclear Information System (INIS)

    Subramanian, A; Dong, L X; Tharian, J; Sennhauser, U; Nelson, B J

    2007-01-01

    Relative displacements between the atomically smooth, nested shells in multiwalled carbon nanotubes (MWNTs) can be used as a robust nanoscale motion enabling mechanism. Here, we report on a novel method suited for structuring large arrays of MWNTs into such nanobearings in a parallel fashion. By creating MWNT nanostructures with nearly identical electrical circuit resistance and heat transport conditions, uniform Joule heating across the array is used to simultaneously engineer the shell geometry via electric breakdown. The biasing approach used optimizes process metrics such as yield and cycle-time. We also present the parallel and piecewise shell engineering at different segments of a single nanotube to construct multiple, but independent, high density bearings. We anticipate this method for constructing electromechanical building blocks to be a fundamental unit process for manufacturing future nanoelectromechanical systems (NEMS) with sophisticated architectures and to drive several nanoscale transduction applications such as GHz-oscillators, shuttles, memories, syringes and actuators

  12. Carbon nanotubes: from nano test tube to nano-reactor.

    Science.gov (United States)

    Khlobystov, Andrei N

    2011-12-27

    Confinement of molecules and atoms inside carbon nanotubes provides a powerful strategy for studying structures and chemical properties of individual molecules at the nanoscale. In this issue of ACS Nano, Allen et al. explore the nanotube as a template leading to the formation of unusual supramolecular and covalent structures. The potential of carbon nanotubes as reactors for synthesis on the nano- and macroscales is discussed in light of recent studies.

  13. Electron emission mechanism of carbon fiber cathode

    International Nuclear Information System (INIS)

    Liu Lie; Li Limin; Wen Jianchun; Wan Hong

    2005-01-01

    Models of electron emission mechanism are established concerning metal and carbon fiber cathodes. Correctness of the electron emission mechanism was proved according to micro-photos and electron scanning photos of cathodes respectively. The experimental results and analysis show that the surface flashover induces the electron emission of carbon fiber cathode and there are electron emission phenomena from the top of the carbon and also from its side surface. In addition, compared with the case of the stainless steel cathode, the plasma expansion velocity for the carbon fiber cathode is slower and the pulse duration of output microwave can be widened by using the carbon fiber cathode. (authors)

  14. Low Cost Carbon Fiber From Renewable Resources

    International Nuclear Information System (INIS)

    Compere, A.L.

    2001-01-01

    The Department of Energy Partnership for a New Generation of Vehicles has shown that, by lowering overall weight, the use of carbon fiber composites could dramatically decrease domestic vehicle fuel consumption. For the automotive industry to benefit from carbon fiber technology, fiber production will need to be substantially increased and fiber price decreased to$7/kg. To achieve this cost objective, alternate precursors to pitch and polyacrylonitrile (PAN) are being investigated as possible carbon fiber feedstocks. Additionally, sufficient fiber to provide 10 to 100 kg for each of the 13 million cars and light trucks produced annually in the U.S. will require an increase of 5 to 50-fold in worldwide carbon fiber production. High-volume, renewable or recycled materials, including lignin, cellulosic fibers, routinely recycled petrochemical fibers, and blends of these components, appear attractive because the cost of these materials is inherently both low and insensitive to changes in petroleum price. Current studies have shown that a number of recycled and renewable polymers can be incorporated into melt-spun fibers attractive as carbon fiber feedstocks. Highly extrudable lignin blends have attractive yields and can be readily carbonized and graphitized. Examination of the physical structure and properties of carbonized and graphitized fibers indicates the feasibility of use in transportation composite applications

  15. Catalytic growth of carbon nanotubes with large inner diameters

    Directory of Open Access Journals (Sweden)

    WEI REN ZHONG

    2005-02-01

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

  16. Catalysts for Efficient Production of Carbon Nanotubes

    Science.gov (United States)

    Sun, Ted X.; Dong, Yi

    2009-01-01

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

  17. Softening of the Radial Breathing Mode in Metallic Carbon Nanotubes

    Czech Academy of Sciences Publication Activity Database

    Farhat, H. (ed.); Sasaki, K.; Kalbáč, Martin; Hofmann, M.; Saito, R.; Dresselhaus, M. S.; Kong, J.

    2009-01-01

    Roč. 102, č. 12 (2009), 126804-1-126804-4 ISSN 0031-9007 Institutional research plan: CEZ:AV0Z40400503 Keywords : metallic carbon nanotubes * radial breathing mode * single waled carbon nanotubes Subject RIV: CG - Electrochemistry Impact factor: 7.328, year: 2009

  18. Apparatus for the laser ablative synthesis of carbon nanotubes

    Science.gov (United States)

    Smith, Michael W.; Jordan, Kevin

    2010-02-16

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

  19. Anode Sheath Switching in a Carbon Nanotube Arc Plasma

    International Nuclear Information System (INIS)

    Fetterman, Abe; Raitses, Yevgeny; Keidar, Michael

    2008-01-01

    The anode ablation rate is investigated as a function of anode diameter for a carbon nanotube arc plasma. It is found that anomalously high ablation occurs for small anode diameters. This result is explained by the formation of a positive anode sheath. The increased ablation rate due to this positive anode sheath could imply greater production rate for carbon nanotubes.

  20. Very short functionalized carbon nanotubes for membrane applications

    NARCIS (Netherlands)

    Fonseca, A.; Reijerkerk, Sander; Potreck, Jens; Nijmeijer, Dorothea C.; Mekhalif, Z.; Delhalle, J.

    2010-01-01

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

  1. Catalyst deposition for the preparation of carbon nanotubes

    DEFF Research Database (Denmark)

    2013-01-01

    patterned surface is configured to ensure that no more than a single island of catalyst is formed on each plateau, so that a sub sequent growth of carbon nanotubes from the deposited islands result in that no more than a single carbon nanotube is grown from each plateau....

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

    NARCIS (Netherlands)

    van Dommele, S.

    2008-01-01

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

  3. Synthesis of nano-carbon (nanotubes, nanofibres, graphene ...

    Indian Academy of Sciences (India)

    In the present study, we report the synthesis of carbon nanotubes (CNTs) using a new natural precursor: castor oil. The CNTs were synthesized by spray pyrolysis of castor oil–ferrocene solution at 850°C under an Ar atmosphere. We also report the synthesis of carbon nitrogen (C–N) nanotubes using castor ...

  4. Electrical conductivity of metal–carbon nanotube structures

    Indian Academy of Sciences (India)

    The electrical properties of asymmetric metal–carbon nanotube (CNT) structures have been studied using density functional theory and non-equilibrium Green's function method with Atomistix tool kit. The models with asymmetric metal contacts and carbon nanotube bear resemblance to experimental set-ups. The study ...

  5. A thermodynamic model for growth mechanisms of multiwall carbon nanotubes.

    Energy Technology Data Exchange (ETDEWEB)

    Kaatz, Forrest H.; Overmyer, Donald L.; Siegal, Michael P.

    2006-02-01

    Multiwall carbon nanotubes are grown via thermal chemical vapor deposition between temperatures of 630 and 830 C using acetylene in nitrogen as the carbon source. This process is modeled using classical thermodynamics to explain the total carbon deposition as a function of time and temperature. An activation energy of 1.60 eV is inferred for nanotube growth after considering the carbon solubility term. Scanning electron microscopy shows growth with diameters increasing linearly with time. Transmission electron microscopy and Raman spectroscopy show multiwall nanotubes surrounded by a glassy-carbon sheath, which grows with increasing wall thickness as growth temperatures and times rise.

  6. Thermodynamic model for growth mechanisms of multiwall carbon nanotubes

    Science.gov (United States)

    Kaatz, F. H.; Siegal, M. P.; Overmyer, D. L.; Provencio, P. P.; Tallant, D. R.

    2006-12-01

    Multiwall carbon nanotubes are grown via thermal chemical vapor deposition between temperatures of 630 and 830°C using acetylene in nitrogen as the carbon source. This process is modeled using classical thermodynamics to explain the total carbon deposition as a function of time and temperature. An activation energy of 1.60eV is inferred for nanotube growth after considering the carbon solubility term. Scanning electron microscopy shows growth with diameters increasing linearly with time. Transmission electron microscopy and Raman spectroscopy show multiwall nanotubes surrounded by a glassy-carbon sheath, which grows with increasing wall thickness as growth temperatures and times rise.

  7. Magnetoelectronic properties of chiral carbon nanotubes and tori

    International Nuclear Information System (INIS)

    Shyu, F L; Tsai, C C; Lee, C H; Lin, M F

    2006-01-01

    Magnetoelectronic properties of chiral carbon nanotubes and toroids are studied for any magnetic field. They are sensitive to the changes in the magnitude and the direction of the magnetic field, as well as the chirality. The important differences between chiral and achiral carbon nanotubes include band symmetry, band curvature, band crossing, band-edge state, state degeneracy, band spacing, energy gap, and semiconductor-metal transition. Carbon tori also exhibit the strong chirality dependence on the field modulation of discrete states. Chiral carbon tori might differ from chiral carbon nanotubes in energy-gap modulation, density of states, and state degeneracy

  8. All-fiber nonlinearity- and dispersion-managed dissipative soliton nanotube mode-locked laser

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Z. [Department of Physics, Bilkent University, 06800 Ankara (Turkey); Nanjing University of Posts and Communications, Nanjing 210003 (China); Popa, D., E-mail: dp387@cam.ac.uk; Wittwer, V. J.; Milana, S.; Hasan, T.; Jiang, Z.; Ferrari, A. C. [Cambridge Graphene Centre, University of Cambridge, Cambridge CB3 0FA (United Kingdom); Ilday, F. Ö. [Department of Physics, Bilkent University, 06800 Ankara (Turkey); Department of Electrical and Electronics Engineering, Bilkent University, 06800 Ankara (Turkey)

    2015-12-14

    We report dissipative soliton generation from an Yb-doped all-fiber nonlinearity- and dispersion-managed nanotube mode-locked laser. A simple all-fiber ring cavity exploits a photonic crystal fiber for both nonlinearity enhancement and dispersion compensation. The laser generates stable dissipative solitons with large linear chirp in the net normal dispersion regime. Pulses that are 8.7 ps long are externally compressed to 118 fs, outperforming current nanotube-based Yb-doped fiber laser designs.

  9. Carbon nanotubes significance in Darcy-Forchheimer flow

    Science.gov (United States)

    Hayat, Tasawar; Rafique, Kiran; Muhammad, Taseer; Alsaedi, Ahmed; Ayub, Muhammad

    2018-03-01

    The present article examines Darcy-Forchheimer flow of water-based carbon nanotubes. Flow is induced due to a curved stretchable surface. Heat transfer mechanism is analyzed in presence of convective heating process. Xue model of nanofluid is employed to study the characteristics of both single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs). Results for both single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs) are achieved and compared. Appropriate transformations correspond to strong nonlinear ordinary differential system. Optimal homotopy analysis method (OHAM) is used for the solution development of the resulting system. The contributions of different sundry variables on the velocity and temperature are studied. Further the skin friction coefficient and local Nusselt number are analyzed graphically for both SWCNTs and MWCNTs cases.

  10. Layered growth of aligned carbon nanotube arrays by pyrolysis

    International Nuclear Information System (INIS)

    Zhang Hongrui; Liang Erjun; Ding Pei; Chao Mingju

    2003-01-01

    Based on the study of reaction temperature and duration of the growth of aligned carbon nanotube arrays, layered aligned multi-wall carbon nanotube (MWNT) films grown directly around a reaction quartz tube in an Ar/H 2 atmosphere by pyrolysis of ferrocene in xylene in a suitable reaction furnace with the help of cobalt powder. The scanning electron microscope and transmission electron microscope images indicated that the obtained arrays were composed of many separated layers with MWNTs. The reaction temperature significantly influenced the alignment of the MWNTs, and an appropriate reaction temperature range for growth was 800-900 deg. C. The diameter of the carbon nanotube increased from 46 to 75 nm with the growth temperature. Besides temperature, the reaction duration influenced the length of the well-aligned carbon nanotubes. There was no significant relation between the growth time and the diameter of the carbon nanotubes in the array

  11. Thermophoretic Motion of Water Nanodroplets confined inside Carbon Nanotubes

    DEFF Research Database (Denmark)

    Zambrano, Harvey A; Walther, Jens Honore; Koumoutsakos, Petros

    2009-01-01

    We study the thermophoretic motion of water nanodroplets confined inside carbon nanotubes using molecular dynamics simulations. We find that the nanodroplets move in the direction opposite the imposed thermal gradient with a terminal velocity that is linearly proportional to the gradient....... The translational motion is associated with a solid body rotation of the water nanodroplet coinciding with the helical symmetry of the carbon nanotube. The thermal diffusion displays a weak dependence on the wetting of the water-carbon nanotube interface. We introduce the use of the Moment Scaling Spectrum (MSS......) in order to determine the characteristics of the motion of the nanoparticles inside the carbon nanotube. The MSS indicates that affinity of the nanodroplet with the walls of the carbon nanotubes is important for the isothermal diffusion, and hence for the Soret coefficient of the system....

  12. Fabrication and characterization of nanocomposites reinforced by carbon nanotubes - (1) synthesis of carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Hseuh Hsiangming; Tai Nyanhwa; Perng Tongping [Dept. of Material Science, National Tsing-Hwa Univ., TW (China); Chyou Sander [Taiwan Power Research Inst., Taiwan Power Co., Taipei (China)

    2003-07-01

    Multi-walled carbon nanotubes (MWCNTs) produced by floating catalyst method were used for reinforcing material in polymeric nanocomposites. Five different kinds of carbon sources (benzene, toluene, xylene, cyclo-hexane, n-hexane) were used as precursors in the thermal chemical vapor deposition process. The products were collected and examined by Raman, HRTEM, and FESEM. The differences in microstructure and morphologies among these products are analyzed and discussed. (orig.)

  13. Cellular cytotoxic response induced by highly purified multi-wall carbon nanotube in human lung cells.

    Science.gov (United States)

    Tsukahara, Tamotsu; Haniu, Hisao

    2011-06-01

    Carbon nanotubes, a promising nanomaterial with unique characteristics, have applications in a variety of fields. The cytotoxic effects of carbon nanotubes are partially due to the induction of oxidative stress; however, the detailed mechanisms of nanotube cytotoxicity and their interaction with cells remain unclear. In this study, the authors focus on the acute toxicity of vapor-grown carbon fiber, HTT2800, which is one of the most highly purified multi-wall carbon nanotubes (MWCNT) by high-temperature thermal treatment. The authors exposed human bronchial epithelial cells (BEAS-2B) to HTT2800 and measured the cellular uptake, mitochondrial function, cellular LDH release, apoptotic signaling, reactive oxygen species (ROS) generation and pro-inflammatory cytokine release. The HTT2800-exposed cells showed cellular uptake of the carbon nanotube, increased cell death, enhanced DNA damage, and induced cytokine release. However, the exposed cells showed no obvious intracellular ROS generation. These cellular and molecular findings suggest that HTT2800 could cause a potentially adverse inflammatory response in BEAS-2B cells.

  14. Towards self-assembled devices, a carbon nanotube approach

    OpenAIRE

    Del Rio Castillo, Antonio Esau

    2012-01-01

    2010/2011 In the last decade the nanostructured carbon materials, especially single walled carbon nanotubes (SWNTs), had emerged as probable substitutes for Silicon in the next generation of electronic devices. This is due to their unique physic and chemical properties. Likewise, scientists all around the world have made a huge effort to introduce carbon materials into the market. Despite this effort, commercial application for carbon nanotubes in electronic devices has not yet been achiev...

  15. Influence of surface chemistry on inkjet printed carbon nanotube films

    International Nuclear Information System (INIS)

    Hopkins, Alan R.; Straw, David C.; Spurrell, Kathryn C.

    2011-01-01

    Carbon nanotube ink chemistry and the proper formulation are crucial for direct-write printing of nanotubes. Moreover, the correct surface chemistry of the self-assembled monolayers that assist the direct deposition of carbon nanotubes onto the substrate is equally important to preserve orientation of the printed carbon nanotubes. We report that the successful formulation of two single walled carbon nanotube (SWNT) inks yields a consistent, homogenous printing pattern possessing the requisite viscosities needed for flow through the microcapillary nozzles of the inkjet printer with fairly modest drying times. The addition of an aqueous sodium silicate allows for a reliable method for forming a uniform carbon nanotube network deposited directly onto unfunctionalized surfaces such as glass or quartz via inkjet deposition. Furthermore, this sodium silicate ingredient helps preserve applied orientation to the printed SWNT solution. Sheet resistivity of this carbon nanotube ink formula printed on quartz decreases as a function of passes and is independent of the substrate. SWNTs were successfully patterned on Au. This amine-based surface chemistry dramatically helps improve the isolation stabilization of the printed SWNTs as seen in the atomic force microscopy (AFM) image. Lastly, using our optimized SWNT ink formula and waveform parameters in the Fuji materials printer, we are able to directly write/print SWNTs into 2D patterns. Dried ink pattern expose and help orient roped carbon nanotubes that are suspended in ordered arrays across the cracks.

  16. Mechanochemical treatment of amorphous carbon from brown sphagnum moss for the preparation of carbon nanotubes

    International Nuclear Information System (INIS)

    Onishchenko, D.V.

    2013-01-01

    Under consideration is the mechanism of multiwalled nanotubes formation during mechanical activation of amorphous carbon synthesized by pyrolysis of sphagnum moss. The formation of nanotubes has been shown to take place in the array of carbon particles. A complex study of the sorption characteristics of carbon nanotubes has been carried out. The dependence of the sorption capacity of carbon nanotubes on their storage time, as well as the effect of the process parameters of nanotubes formation on their ability for oxidative modification, is represented. (authors)

  17. Surface plasmon observed for carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Bursill, L A; Stadelmann, P A [Ecole Polytechnique Federale, Lausanne (Switzerland); Peng, J L; Prawer, S [Melbourne Univ., Parkville, VIC (Australia). School of Physics

    1994-12-31

    This paper presents parallel electron energy loss spectra (PEELS) results, obtained for individual carbon nanotubes, using nanoprobe techniques (1-2 nm diameter electron beam), energy resolution 0.5 eV and collection times of 4-25 sec. The aim was to use a nanoprobe to compare PEELS spectra from different parts of a tube, in order to search for variations in sp{sup 2}/sp{sup 3} bonding ratios as well as to look for orientation dependent plasmon and core-loss phenomena. It also seemed interesting to compare results for nanotubes with those for other varieties of graphitized carbons. The most interesting result so far was the appearance of a 15 eV plasmon peak, which appeared only for tubes containing {<=} about 12 graphite-like layers. This peak did not shift significantly with tube size. A low-loss peaks at 6 eV of variable relative intensity was also observed this peak was relatively very weak for amorphous tubes; it appears to be characteristic of graphite-like layers, as found for nanotubes and, of course, graphite itself. This paper is restricted to discussion of the low-loss results. The experimental techniques are first described, including some details of the methods which may be used to disperse and support sooty carbons for high-resolution transmission electron microscopy. The results are then presented, followed by an interpretation of all the low-loss PEELS results, including those of the other authors. 14 refs., 2 figs.

  18. Carbon nanotubes for high-performance logic

    OpenAIRE

    Chen, Zhihong; Wong, H.S. Phillip; Mitra, Subhasish; Bol, Aggeth; Peng, Lianmao; Hills, Gage; Thissen, Nick

    2014-01-01

    Single-wall carbon nanotubes (CNTs) were discovered in 1993 and have been an area of intense research since then. They offer the right dimensions to explore material science and physical chemistry at the nanoscale and are the perfect system to study low-dimensional physics and transport. In the past decade, more attention has been shifted toward making use of this unique nanomaterial in real-world applications. In this article, we focus on potential applications of CNTs in the high-performanc...

  19. Metallic Carbon Nanotubes and Ag Nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Brus, Louis E

    2014-03-04

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

  20. Carbon Nanotubes Filled with Ferromagnetic Materials

    Directory of Open Access Journals (Sweden)

    Albrecht Leonhardt

    2010-08-01

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

  1. Fibrous composites comprising carbon nanotubes and silica

    Science.gov (United States)

    Peng, Huisheng [Shanghai, CN; Zhu, Yuntian Theodore [Cary, NC; Peterson, Dean E [Los Alamos, NM; Jia, Quanxi [Los Alamos, NM

    2011-10-11

    Fibrous composite comprising a plurality of carbon nanotubes; and a silica-containing moiety having one of the structures: (SiO).sub.3Si--(CH.sub.2).sub.n--NR.sub.1R.sub.2) or (SiO).sub.3Si--(CH.sub.2).sub.n--NCO; where n is from 1 to 6, and R.sub.1 and R.sub.2 are each independently H, CH.sub.3, or C.sub.2H.sub.5.

  2. Biomineralization of superhydrophilic vertically aligned carbon nanotubes.

    Science.gov (United States)

    Marsi, Teresa Cristina O; Santos, Tiago G; Pacheco-Soares, Cristina; Corat, Evaldo J; Marciano, Fernanda R; Lobo, Anderson O

    2012-03-06

    Vertically aligned carbon nanotubes (VACNT) promise a great role for the study of tissue regeneration. In this paper, we introduce a new biomimetic mineralization routine employing superhydrophilic VACNT films as highly stable template materials. The biomineralization was obtained after VACNT soaking in simulated body fluid solution. Detailed structural analysis reveals that the polycrystalline biological apatites formed due to the -COOH terminations attached to VACNT tips after oxygen plasma etching. Our approach not only provides a novel route for nanostructured materials, but also suggests that COOH termination sites can play a significant role in biomimetic mineralization. These new nanocomposites are very promising as nanobiomaterials due to the excellent human osteoblast adhesion.

  3. Carbon Nanotubes Filled with Ferromagnetic Materials

    Science.gov (United States)

    Weissker, Uhland; Hampel, Silke; Leonhardt, Albrecht; Büchner, Bernd

    2010-01-01

    Carbon nanotubes (CNT) filled with ferromagnetic metals like iron, cobalt or nickel are new and very interesting nanostructured materials with a number of unique properties. In this paper we give an overview about different chemical vapor deposition (CVD) methods for their synthesis and discuss the influence of selected growth parameters. In addition we evaluate possible growth mechanisms involved in their formation. Moreover we show their identified structural and magnetic properties. On the basis of these properties we present different application possibilities. Some selected examples reveal the high potential of these materials in the field of medicine and nanotechnology. PMID:28883334

  4. Disorder, Pseudospins, and Backscattering in Carbon Nanotubes

    International Nuclear Information System (INIS)

    McEuen, Paul L.; Bockrath, Marc; Cobden, David H.; Yoon, Young-Gui; Louie, Steven G.

    1999-01-01

    We address the effects of disorder on the conducting properties of metal and semiconducting carbon nanotubes. Experimentally, the mean free path is found to be much larger in metallic tubes than in doped semiconducting tubes. We show that this result can be understood theoretically if the disorder potential is long ranged. The effects of a pseudospin index that describes the internal sublattice structure of the states lead to a suppression of scattering in metallic tubes, but not in semiconducting tubes. This conclusion is supported by tight-binding calculations. (c) 1999 The American Physical Society

  5. Carbon Nanotube Integration with a CMOS Process

    Science.gov (United States)

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

    2010-01-01

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

  6. Superconductivity in single wall carbon nanotubes

    Directory of Open Access Journals (Sweden)

    H Yavari

    2009-08-01

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

  7. Spin transport in ferromagnetically contacted carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-11-15

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

  8. Patterned functional carbon fibers from polyethylene

    Energy Technology Data Exchange (ETDEWEB)

    Hunt, Marcus A [ORNL; Saito, Tomonori [ORNL; Brown, Rebecca H [ORNL; Kumbhar, Amar S [University of North Carolina, Chapel Hill; Naskar, Amit K [ORNL

    2012-01-01

    Patterned, continuous carbon fibers with controlled surface geometry were produced from a novel melt-processible carbon precursor. This portends the use of a unique technique to produce such technologically innovative fibers in large volume for important applications. The novelties of this technique include ease of designing and fabricating fibers with customized surface contour, the ability to manipulate filament diameter from submicron scale to a couple of orders of magnitude larger scale, and the amenable porosity gradient across the carbon wall by diffusion controlled functionalization of precursor. The geometry of fiber cross-section was tailored by using bicomponent melt-spinning with shaped dies and controlling the melt-processing of the precursor polymer. Circular, trilobal, gear-shaped hollow fibers, and solid star-shaped carbon fibers of 0.5 - 20 um diameters, either in self-assembled bundle form, or non-bonded loose filament form, were produced by carbonizing functionalized-polyethylene fibers. Prior to carbonization, melt-spun fibers were converted to a char-forming mass by optimizing the sulfonation on polyethylene macromolecules. The fibers exhibited distinctly ordered carbon morphologies at the outside skin compared to the inner surface or fiber core. Such order in carbon microstructure can be further tuned by altering processing parameters. Partially sulfonated polyethylene-derived hollow carbon fibers exhibit 2-10 fold surface area (50-500 m2/g) compared to the solid fibers (10-25 m2/g) with pore sizes closer to the inside diameter of the filaments larger than the sizes on the outer layer. These specially functionalized carbon fibers hold promise for extraordinary performance improvements when used, for example, as composite reinforcements, catalyst support media, membranes for gas separation, CO2 sorbents, and active electrodes and current collectors for energy storage applications.

  9. Thermodynamics on Soluble Carbon Nanotubes: How Do DNA Molecules Replace Surfactants on Carbon Nanotubes?

    Science.gov (United States)

    Kato, Yuichi; Inoue, Ayaka; Niidome, Yasuro; Nakashima, Naotoshi

    2012-01-01

    Here we represent thermodynamics on soluble carbon nanotubes that enables deep understanding the interactions between single-walled carbon nanotubes (SWNTs) and molecules. We selected sodium cholate and single-stranded cytosine oligo-DNAs (dCn (n = 4, 5, 6, 7, 8, 10, 15, and 20)), both of which are typical SWNT solubilizers, and successfully determined thermodynamic properties (ΔG, ΔH and ΔS values) for the exchange reactions of sodium cholate on four different chiralities of SWNTs ((n,m) = (6,5), (7,5), (10,2), and (8,6)) for the DNAs. Typical results contain i) the dC5 exhibited an exothermic exchange, whereas the dC6, 8, 10, 15, and 20 materials exhibited endothermic exchanges, and ii) the energetics of the dC4 and dC7 exchanges depended on the associated chiral indices and could be endothermic or exothermic. The presented method is general and is applicable to any molecule that interacts with nanotubes. The study opens a way for science of carbon nanotube thermodynamics. PMID:23066502

  10. Tuning the conductance of carbon nanotubes with encapsulated molecules

    International Nuclear Information System (INIS)

    Meunier, Vincent; Sumpter, Bobby G

    2007-01-01

    It was recently shown that a molecule encapsulated inside a carbon nanotube can be used to devise a novel type of non-volatile memory element. At the heart of the mechanism for storing and reading information is the new concept of a molecular gate where the molecule acts as a passive gate that hinders the flow of electrons for a given position relative to the nanotube host. By systematically exploring the effects of encapsulation of an acceptor molecule in a series of carbon nanotubes, we show that the reliability of the memory mechanism is very sensitive to the interaction between the nanotube host and the molecule guest

  11. Conductive Cotton Textile from Safely Functionalized Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Mohammad Jellur Rahman

    2015-01-01

    Full Text Available Electroconductive cotton textile has been prepared by a simple dipping-drying coating technique using safely functionalized multiwalled carbon nanotubes (f-MWCNTs. Owing to the surface functional groups, the f-MWCNTs become strongly attached with the cotton fibers forming network armors on their surfaces. As a result, the textile exhibits enhanced electrical properties with improved thermal conductivity and therefore is demonstrated as a flexible electrothermal heating element. The fabricated f-MWCNTs/cotton textile can be heated uniformly from room temperature to ca. 100°C within few minutes depending on the applied voltage. The textile shows good thermal stability and repeatability during a long-term heating test.

  12. Nanotube bundle oscillators: Carbon and boron nitride nanostructures

    International Nuclear Information System (INIS)

    Thamwattana, Ngamta; Hill, James M.

    2009-01-01

    In this paper, we investigate the oscillation of a fullerene that is moving within the centre of a bundle of nanotubes. In particular, certain fullerene-nanotube bundle oscillators, namely C 60 -carbon nanotube bundle, C 60 -boron nitride nanotube bundle, B 36 N 36 -carbon nanotube bundle and B 36 N 36 -boron nitride nanotube bundle are studied using the Lennard-Jones potential and the continuum approach which assumes a uniform distribution of atoms on the surface of each molecule. We address issues regarding the maximal suction energies of the fullerenes which lead to the generation of the maximum oscillation frequency. Since bundles are also found to comprise double-walled nanotubes, this paper also examines the oscillation of a fullerene inside a double-walled nanotube bundle. Our results show that the frequencies obtained for the oscillation within double-walled nanotube bundles are slightly higher compared to those of single-walled nanotube bundle oscillators. Our primary purpose here is to extend a number of established results for carbon to the boron nitride nanostructures.

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

    Science.gov (United States)

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

    2014-01-01

    The use of biologics, polymers, silicon materials, carbon materials, and metals has been proposed for the preparation of innovative drug delivery devices. One of the most promising materials in this field are the carbon-nanotubes composites and hybrid materials coupling the advantages of polymers (biocompatibility and biodegradability) with those of carbon nanotubes (cellular uptake, stability, electromagnatic, and magnetic behavior). The applicability of polymer-carbon nanotubes composites in drug delivery, with particular attention to the controlled release by composites hydrogel, is being extensively investigated in the present review. PMID:24587993

  14. Spontaneous and controlled-diameter synthesis of single-walled and few-walled carbon nanotubes

    Science.gov (United States)

    Inoue, Shuhei; Lojindarat, Supanat; Kawamoto, Takahiro; Matsumura, Yukihiko; Charinpanitkul, Tawatchai

    2018-05-01

    In this study, we explored the spontaneous and controlled-diameter growth of carbon nanotubes. We evaluated the effects of catalyst density, reduction time, and a number of catalyst coating on the substrate (for multi-walled carbon nanotubes) on the diameter of single-walled carbon nanotubes and the number of layers in few-walled carbon nanotubes. Increasing the catalyst density and reduction time increased the diameters of the carbon nanotubes, with the average diameter increasing from 1.05 nm to 1.86 nm for single-walled carbon nanotubes. Finally, we succeeded in synthesizing a significant double-walled carbon nanotube population of 24%.

  15. Carbon nanotube/carbon nanotube composite AFM probes prepared using ion flux molding

    Science.gov (United States)

    Chesmore, Grace; Roque, Carrollyn; Barber, Richard

    The performance of carbon nanotube-carbon nanotube composite (CNT/CNT composite) atomic force microscopy (AFM) probes is compared to that of conventional Si probes in AFM tapping mode. The ion flux molding (IFM) process, aiming an ion beam at the CNT probe, aligns the tip to a desired angle. The result is a relatively rigid tip that is oriented to offset the cantilever angle. Scans using these probes reveal an improvement in image accuracy over conventional tips, while allowing higher aspect ratio imaging of 3D surface features. Furthermore, the lifetimes of CNT-CNT composite tips are observed to be longer than both conventional tips and those claimed for other CNT technologies. Novel applications include the imaging of embiid silk. Supported by the Clare Boothe Luce Research Scholars Award and Carbon Design Innovations.

  16. Oxidation of Carbon Nanotubes in an Ionizing Environment.

    Science.gov (United States)

    Koh, Ai Leen; Gidcumb, Emily; Zhou, Otto; Sinclair, Robert

    2016-02-10

    In this work, we present systematic studies on how an illuminating electron beam which ionizes molecular gas species can influence the mechanism of carbon nanotube oxidation in an environmental transmission electron microscope (ETEM). We found that preferential attack of the nanotube tips is much more prevalent than for oxidation in a molecular gas environment. We establish the cumulative electron doses required to damage carbon nanotubes from 80 keV electron beam irradiation in gas versus in high vacuum. Our results provide guidelines for the electron doses required to study carbon nanotubes within or without a gas environment, to determine or ameliorate the influence of the imaging electron beam. This work has important implications for in situ studies as well as for the oxidation of carbon nanotubes in an ionizing environment such as that occurring during field emission.

  17. Filament Winding Multifunctional Carbon Nanotube Composites of Various Dimensionality

    Science.gov (United States)

    Wells, Brian David

    Carbon nanotubes (CNT) have been long considered an optimal material for composites due to their high strength, high modulus, and electrical/thermal conductivity. These composite materials have the potential to be used in the aerospace, computer, automotive, medical industry as well as many others. The nano dimensions of these structures make controlled alignment and distribution difficult using many production techniques. An area that shows promise for controlled alignment is the formation of CNT yarns. Different approaches have been used to create yarns with various winding angles and diameters. CNTs resemble traditional textile fiber structures due to their one-dimensional dimensions, axial strength and radial flexibility. One difference is, depending on the length, CNTs can have aspect ratios that far exceed those of traditional textile fibers. This can complicate processing techniques and cause agglomeration which prevents optimal structures from being created. However, with specific aspect ratios and spatial distributions a specific type of CNT, vertically aligned spinnable carbon nanotubes (VASCNTs), have interesting properties that allow carbon nanotubes to be drawn from an array in a continuous aligned web. This dissertation examines the feasibility of combining VASCNTs with another textile manufacturing process, filament winding, to create structures with various levels of dimensionality. While yarn formation with CNTs has been largely studied, there has not been significant work studying the use of VASCNTs to create composite materials. The studies that have been produces revolve around mixing CNTs into epoxy or creating uni-directional wound structures. In this dissertation VASCNTs are used to create filament wound materials with various degrees of alignment. These structures include 1 dimensional coatings applied to non-conductive polymer monofilaments, two dimensional multifunctional adhesive films, and three dimensional hybrid-nano composites. The

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

    International Nuclear Information System (INIS)

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

    2013-01-01

    Carbon nanotubes are promising nanostructures for many applications in materials industry and biotechnology. However, it is mandatory to evaluate their toxicity and environmental implications. We evaluated nitric acid treated multiwalled carbon nanotubes (HNO 3 -MWCNT) toxicity in Nile tilapia (Oreochromis niloticus) and also the lead (Pb) toxicity modulation after the nanotube interaction. Industrial grade multiwalled carbon nanotubes [Ctube 100, CNT Co. Ltd] were treated with 9M HNO 3 for 12h at 150°C to generate oxygenated groups on the nanotube surface, to improve water dispersion and heavy metal interaction. The HNO 3 -treated multiwalled carbon nanotubes were physico-chemically characterized by several techniques [e.g. TEM, FE-SEM, TGA, ζ-potential and Raman spectroscopy]. HNO 3 -MWCNT did not show toxicity on Nile tilapia when the concentration ranged from 0.1 to 3.0 mg/L, and the maximum exposure time was 96h. After 24, 48, 72 and 96h the LC50 values of Pb were 1.65, 1.32, 1.10 and 0.99 mg/L, respectively. To evaluate the Pb-nanotube interaction influence on the ecotoxicity, we submitted the Nile tilapia to different concentrations of Pb mixed with a non-toxic concentration of HNO 3 -MWCNT (1.0 mg/L). After 24, 48, 72, 96 h the LC50 values of Pb plus nanotubes were: 0.32, 0.25, 0.20, 0.18 mg/L, respectively. These values showed a synergistic effect after Pb-nanotube interaction since Pb toxicity increased over five times. X-ray energy dispersive spectroscopy (EDS) was used to confirm lead adsorption on the carbon nanotube oxidized surface. The exposure of Nile tilapia to Pb plus HNO 3 -MWCNT caused both oxygen consumption and ammonium excretion decrease, when compared to the control. Finally, our results show that carbon nanotubes interact with classical pollutants drawing attention to the environmental implications.

  19. Fermentation based carbon nanotube multifunctional bionic composites

    Science.gov (United States)

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

    2016-06-01

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

  20. Carbon nanotube-based ethanol sensors

    International Nuclear Information System (INIS)

    Brahim, Sean; Colbern, Steve; Gump, Robert; Moser, Alex; Grigorian, Leonid

    2009-01-01

    Sensors containing metal-carbon nanotube (CNT) hybrid materials as the active sensing layer were demonstrated for ethanol vapor detection at room temperature. The metal-CNT hybrid materials were synthesized by infiltrating single wall carbon nanotubes (SWNTs) with the transition metals Ti, Mn, Fe, Co, Ni, Pd or Pt. Each sensor was prepared by drop-casting dilute dispersions of a metal-CNT hybrid onto quartz substrate electrodes and the impedimetric responses to varying ethanol concentration were recorded. Upon exposure to ethanol vapor, the ac impedance (Z') of the sensors was found to decrease to different extents. The sensor containing pristine CNT material was virtually non-responsive at low ethanol concentrations (<50 ppm). In contrast, all metal-CNT hybrid sensors showed extremely high sensitivity to trace ethanol levels with 100-fold or more gains in sensitivity relative to the starting SWNT sensor. All hybrid sensors, with the exception of Ni filled CNT, exhibited significantly larger sensor responses to ethanol vapor up to 250 ppm compared to the starting SWNT sensor.

  1. Manufacturing of Nanocomposite Carbon Fibers and Composite Cylinders

    Science.gov (United States)

    Tan, Seng; Zhou, Jian-guo

    2013-01-01

    Pitch-based nanocomposite carbon fibers were prepared with various percentages of carbon nanofibers (CNFs), and the fibers were used for manufacturing composite structures. Experimental results show that these nanocomposite carbon fibers exhibit improved structural and electrical conductivity properties as compared to unreinforced carbon fibers. Composite panels fabricated from these nanocomposite carbon fibers and an epoxy system also show the same properties transformed from the fibers. Single-fiber testing per ASTM C1557 standard indicates that the nanocomposite carbon fiber has a tensile modulus of 110% higher, and a tensile strength 17.7% times higher, than the conventional carbon fiber manufactured from pitch. Also, the electrical resistance of the carbon fiber carbonized at 900 C was reduced from 4.8 to 2.2 ohm/cm. The manufacturing of the nanocomposite carbon fiber was based on an extrusion, non-solvent process. The precursor fibers were then carbonized and graphitized. The resultant fibers are continuous.

  2. Substitution reactions of carbon nanotube template

    Science.gov (United States)

    Li, Chi Pui; Chen, Ying; Gerald, John Fitz

    2006-05-01

    Substitution reactions between carbon nanotube (CNT) template and SiO with the formation of carbon rich silicon oxide nanowires (SiO-C-NWs) have been investigated using transmission electron microscopy and x-ray energy dispersive spectroscopy. The reaction was carried out by thermal annealing at 1200°C for 1h of a mixture of silicon monoxide (SiO) and iron (II) phthalocyanine, FeC32N8H16 (FePc) powders. Multiwalled CNTs were produced first via pyrolysis of FePc at a lower temperature (1000°C ). SiO vapors reacted with the CNTs at higher temperatures to produce amorphous SiO-C-NWs with a uniform diameter and a length in tens of micrometers. The special bamboolike structure of the CNTs allows the reaction to start from the external surface of the tubes and transform each CNT into a solid nanowire section by section.

  3. Improving Fatigue Performance of GFRP Composite Using Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Moneeb Genedy

    2015-01-01

    Full Text Available Glass fiber reinforced polymers (GFRP have become a preferable material for reinforcing or strengthening reinforced concrete structures due to their corrosion resistance, high strength to weight ratio, and relatively low cost compared with carbon fiber reinforced polymers (CFRP. However, the limited fatigue life of GFRP hinders their use in infrastructure applications. For instance, the low fatigue life of GFRP caused design codes to impose stringent stress limits on GFRP that rendered their use non-economic under significant cyclic loads in bridges. In this paper, we demonstrate that the fatigue life of GFRP can be significantly improved by an order of magnitude by incorporating Multi-Wall Carbon Nanotubes (MWCNTs during GFRP fabrication. GFRP coupons were fabricated and tested under static tension and cyclic tension with mean fatigue stress equal to 40% of the GFRP tensile strength. Microstructural investigations using scanning electron microscopy (SEM and Fourier Transform Infrared (FTIR spectroscopy were used for further investigation of the effect of MWCNTs on the GFRP composite. The experimental results show the 0.5 wt% and the 1.0 wt% MWCNTs were able to improve the fatigue life of GFRP by 1143% and 986%, respectively, compared with neat GFRP.

  4. Fabrication of mesoporous and high specific surface area lanthanum carbide-carbon nanotube composites

    International Nuclear Information System (INIS)

    Biasetto, L.; Carturan, S.; Maggioni, G.; Zanonato, P.; Bernardo, P. Di; Colombo, P.; Andrighetto, A.; Prete, G.

    2009-01-01

    Mesoporous lanthanum carbide-carbon nanotube composites were produced by means of carbothermal reaction of lanthanum oxide, graphite and multi-walled carbon nanotube mixtures under high vacuum. Residual gas analysis revealed the higher reactivity of lanthanum oxide towards carbon nanotubes compared to graphite. After sintering, the composites revealed a specific surface area increasing with the amount of carbon nanotubes introduced. The meso-porosity of carbon nanotubes was maintained after thermal treatment.

  5. Photoconductivity of Activated Carbon Fibers

    Science.gov (United States)

    Kuriyama, K.; Dresselhaus, M. S.

    1990-08-01

    The photoconductivity is measured on a high-surface-area disordered carbon material, namely activated carbon fibers, to investigate their electronic properties. Measurements of decay time, recombination kinetics and temperature dependence of the photoconductivity generally reflect the electronic properties of a material. The material studied in this paper is a highly disordered carbon derived from a phenolic precursor, having a huge specific surface area of 1000--2000m{sup 2}/g. Our preliminary thermopower measurements suggest that this carbon material is a p-type semiconductor with an amorphous-like microstructure. The intrinsic electrical conductivity, on the order of 20S/cm at room temperature, increases with increasing temperature in the range 30--290K. In contrast with the intrinsic conductivity, the photoconductivity in vacuum decreases with increasing temperature. The recombination kinetics changes from a monomolecular process at room temperature to a biomolecular process at low temperatures. The observed decay time of the photoconductivity is {approx equal}0.3sec. The magnitude of the photoconductive signal was reduced by a factor of ten when the sample was exposed to air. The intrinsic carrier density and the activation energy for conduction are estimated to be {approx equal}10{sup 21}/cm{sup 3} and {approx equal}20meV, respectively. The majority of the induced photocarriers and of the intrinsic carriers are trapped, resulting in the long decay time of the photoconductivity and the positive temperature dependence of the conductivity.

  6. Illuminating the future of silicon photonics: optical coupling of carbon nanotubes to microrings

    International Nuclear Information System (INIS)

    Kato, Y K

    2015-01-01

    Advances in carbon nanotube material quality and processing techniques have led to an increased interest in nanotube photonics. In particular, emission in the telecommunication wavelengths makes nanotubes compatible with silicon photonics. Noury et al (2014 Nanotechnology 25 215201) have reported on carbon nanotube photoluminescence coupled to silicon microring resonators, underscoring the advantage of combining carbon nanotube emitters with silicon photonics. Their results open up the possibility of using nanotubes in other waveguide-based devices, taking advantage of well-established technologies. (viewpoint)

  7. 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

  8. Dephasing and hyperfine interaction in carbon nanotubes double quantum dots

    DEFF Research Database (Denmark)

    Reynoso, Andres Alejandro; Flensberg, Karsten

    2012-01-01

    We study theoretically the return probability experiment, which is used to measure the dephasing time T-2*, in a double quantum dot (DQD) in semiconducting carbon nanotubes with spin-orbit coupling and disorder-induced valley mixing. Dephasing is due to hyperfine interaction with the spins of the C...... with these for DQDs in clean nanotubes, whereas the disorder effect is always relevant when the magnetic field is perpendicular to the nanotube axis....

  9. Local gate control in carbon nanotube quantum devices

    Science.gov (United States)

    Biercuk, Michael Jordan

    This thesis presents transport measurements of carbon nanotube electronic devices operated in the quantum regime. Nanotubes are contacted by source and drain electrodes, and multiple lithographically-patterned electrostatic gates are aligned to each device. Transport measurements of device conductance or current as a function of local gate voltages reveal that local gates couple primarily to the proximal section of the nanotube, hence providing spatially localized control over carrier density along the nanotube length. Further, using several different techniques we are able to produce local depletion regions along the length of a tube. This phenomenon is explored in detail for different contact metals to the nanotube. We utilize local gating techniques to study multiple quantum dots in carbon nanotubes produced both by naturally occurring defects, and by the controlled application of voltages to depletion gates. We study double quantum dots in detail, where transport measurements reveal honeycomb charge stability diagrams. We extract values of energy-level spacings, capacitances, and interaction energies for this system, and demonstrate independent control over all relevant tunneling rates. We report rf-reflectometry measurements of gate-defined carbon nanotube quantum dots with integrated charge sensors. Aluminum rf-SETs are electrostatically coupled to carbon nanotube devices and detect single electron charging phenomena in the Coulomb blockade regime. Simultaneous correlated measurements of single electron charging are made using reflected rf power from the nanotube itself and from the rf-SET on microsecond time scales. We map charge stability diagrams for the nanotube quantum dot via charge sensing, observing Coulomb charging diamonds beyond the first order. Conductance measurements of carbon nanotubes containing gated local depletion regions exhibit plateaus as a function of gate voltage, spaced by approximately 1e2/h, the quantum of conductance for a single

  10. Rotational actuator of motor based on carbon nanotubes

    Science.gov (United States)

    Zettl, Alexander K.; Fennimore, Adam M.; Yuzvinsky, Thomas D.

    2008-11-18

    A rotational actuator/motor based on rotation of a carbon nanotube is disclosed. The carbon nanotube is provided with a rotor plate attached to an outer wall, which moves relative to an inner wall of the nanotube. After deposit of a nanotube on a silicon chip substrate, the entire structure may be fabricated by lithography using selected techniques adapted from silicon manufacturing technology. The structures to be fabricated may comprise a multiwall carbon nanotube (MWNT), two in plane stators S1, S2 and a gate stator S3 buried beneath the substrate surface. The MWNT is suspended between two anchor pads and comprises a rotator attached to an outer wall and arranged to move in response to electromagnetic inputs. The substrate is etched away to allow the rotor to freely rotate. Rotation may be either in a reciprocal or fully rotatable manner.

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

    International Nuclear Information System (INIS)

    Zhang Ying; Cao Juexian; Yang Wei

    2008-01-01

    We studied the structural and electronic properties of carbon nanotubes under hydrostatic pressures based on molecular dynamics simulations and first principles band structure calculations. It is found that carbon nanotubes experience a hard-to-soft transition as external pressure increases. The bulk modulus of soft phase is two orders of magnitude smaller than that of hard phase. The band structure calculations show that band gap of (10, 0) nanotube increases with the increase of pressure at low pressures. Above a critical pressure (5.70GPa), band gap of (10, 0) nanotube drops rapidly and becomes zero at 6.62GPa. Moreover, the calculated charge density shows that a large pressure can induce an sp 2 -to-sp 3 bonding transition, which is confirmed by recent experiments on deformed carbon nanotubes

  12. Effect of epoxy coatings on carbon fibers during manufacture of carbon fiber reinforced resin matrix composites

    International Nuclear Information System (INIS)

    Guo, Hui; Huang, Yudong; Liu, Li; Shi, Xiaohua

    2010-01-01

    The changes in oxygen and nitrogen during manufacture of the carbon fiber reinforced resin matrix composites were measured using the X-ray photoelectron spectroscopy method. The effects of the change in oxygen and nitrogen on the strength of the carbon fibers were investigated and the results revealed that the change of the tensile strength with increasing heat curing temperature was attributed to the change in the surface flaws of the carbon fibers because the carbon fibers are sensitive to the surface flaws. The effect of the surface energy that was calculated using Kaelble's method on the strength of the carbon fibers was investigated. Furthermore, the surface roughness of the carbon fibers was measured using atom force microscopy. The change trend of roughness was reverse to that of the strength, which was because of the brittle fracture of the carbon fibers.

  13. Fabrication of Carbon Nanotube Polymer Actuator Using Nanofiber Sheet

    Science.gov (United States)

    Kato, Hayato; Shimizu, Akikazu; Sato, Taiga; Kushida, Masahito

    2017-11-01

    Carbon nanotube polymer actuators were developed using composite nanofiber sheets fabricated by multi-walled carbon nanotubes(MWCNTs) and poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP). Nanofiber sheets were fabricated by electrospinning method. The effect of flow rate and polymer concentration on nanofiber formation were verified for optimum condition for fabricating nanofiber sheets. We examined the properties of MWCNT/PVDF-HFP nanofiber sheets, as follows. Electrical conductivity and mechanical strength increased as the MWCNT weight ratio increased. We fabricated carbon nanotube polymer actuators using MWCNT/PVDF-HFP nanofiber sheets and succeeded in operating of our actuators.

  14. Correlation and dimensional effects of trions in carbon nanotubes

    DEFF Research Database (Denmark)

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

    2010-01-01

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

  15. Control of carbon nanotube growth using cobalt nanoparticles as catalyst

    International Nuclear Information System (INIS)

    Huh, Yoon; Green, Malcolm L.H.; Kim, Young Heon; Lee, Jeong Yong; Lee, Cheol Jin

    2005-01-01

    We have controllably grown carbon nanotubes using uniformly distributed cobalt nanoparticles as catalyst. Cobalt nanoparticles with a uniform size were synthesized by chemical reaction and colloidal solutions including the cobalt nanoparticles were prepared. The cobalt nanoparticles were uniformly distributed on silicon substrates by a spin-coating method. Carbon nanotubes with a uniform diameter were synthesized on the cobalt nanoparticles by thermal chemical vapor deposition of acetylene gas. The density and vertical alignment of carbon nanotubes could be controlled by adjusting the density of cobalt (Co) nanoparticles

  16. Raman spectroscopic characterization of multiwall carbon nanotubes and of composites

    Directory of Open Access Journals (Sweden)

    L. Bokobza

    2012-07-01

    Full Text Available In this work Raman spectroscopy was used for extensive characterization of multiwall carbon nanotube (MWNTs and of MWCNTs/rubber composites. We have measured the Raman spectra of bundled and dispersed multiwall carbon nanotubes. All the Raman bands of the carbon nanotubes are seen to shift to higher wavenumbers upon debundling on account of less intertube interactions. Effects of laser irradiation were also investigated. Strong effects are observed by changing the wavelength of the laser excitation. On the other hand, at a given excitation wavelength, changes on the Raman bands are observed by changing the laser power density due to sample heating during the measurement procedure.

  17. Applications of Carbon Nanotubes in Biotechnology and Biomedicine

    Science.gov (United States)

    Bekyarova, Elena; Ni, Yingchun; Malarkey, Erik B.; Montana, Vedrana; McWilliams, Jared L.; Haddon, Robert C.; Parpura, Vladimir

    2009-01-01

    Due to their electrical, chemical, mechanical and thermal properties, carbon nanotubes are one of the most promising materials for the electronics, computer and aerospace industries. Here, we discuss their properties in the context of future applications in biotechnology and biomedicine. The purification and chemical modification of carbon nanotubes with organic, polymeric and biological molecules are discussed. Additionally we review their uses in biosensors, assembly of structures and devices, scanning probe microscopy and as substrates for neuronal growth. We note that additional toxicity studies of carbon nanotubes are necessary so that exposure guidelines and safety regulations can be established in a timely manner. PMID:19763242

  18. The mechanisms for filling carbon nanotubes with molten salts: carbon nanotubes as energy landscape filters

    International Nuclear Information System (INIS)

    Bishop, Clare L; Wilson, Mark

    2009-01-01

    The mechanisms for filling carbon nanotubes with molten salts are investigated using molecular dynamics computer simulation. Inorganic nanotubular structures, whose morphologies can be rationalized in terms of the folding, or the removal of sections from, planes of square nets are found to form. The formation mechanisms are found to follow a 'chain-by-chain' motif in which the structures build systematically from charge neutral M-X-M-Xc chains. The formation mechanisms are rationalized in terms of the ion-ion interactions (intra-chain and inter-chain terms). In addition, the mechanisms of filling are discussed in terms of a 'hopping' between basins on the underlying energy landscape. The role of the carbon nanotube as an energy landscape filter is discussed.

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

    KAUST Repository

    Li, Jingqi; Wang, Qingxiao; Yue, Weisheng; Guo, Zaibing; LI, LIANG; Zhao, Chao; Wang, Xianbin; Abutaha, Anas I.; Alshareef, Husam N.; Zhang, Yafei; Zhang, Xixiang

    2014-01-01

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

  20. Bismuth oxide nanotubes-graphene fiber-based flexible supercapacitors

    Science.gov (United States)

    Gopalsamy, Karthikeyan; Xu, Zhen; Zheng, Bingna; Huang, Tieqi; Kou, Liang; Zhao, Xiaoli; Gao, Chao

    2014-07-01

    Graphene-bismuth oxide nanotube fiber as electrode material for constituting flexible supercapacitors using a PVA/H3PO4 gel electrolyte is reported with a high specific capacitance (Ca) of 69.3 mF cm-2 (for a single electrode) and 17.3 mF cm-2 (for the whole device) at 0.1 mA cm-2, respectively. Our approach opens the door to metal oxide-graphene hybrid fibers and high-performance flexible electronics.Graphene-bismuth oxide nanotube fiber as electrode material for constituting flexible supercapacitors using a PVA/H3PO4 gel electrolyte is reported with a high specific capacitance (Ca) of 69.3 mF cm-2 (for a single electrode) and 17.3 mF cm-2 (for the whole device) at 0.1 mA cm-2, respectively. Our approach opens the door to metal oxide-graphene hybrid fibers and high-performance flexible electronics. Electronic supplementary information (ESI) available: Equations and characterization. SEM images of GGO, XRD and XPS of Bi2O3 NTs, HRTEM images and EDX Spectra of Bi2O3 NT5-GF, CV curves of Bi2O3NT5-GF, Bi2O3 NTs and bismuth nitrate in three-electrode system (vs. Ag/AgCl). CV and GCD curves of Bi2O3 NT1-GF and Bi2O3 NT3-GF. See DOI: 10.1039/c4nr02615b