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Sample records for high-performance carbon nanotube

  1. High Performance Multiwall Carbon Nanotube Bolometers

    DTIC Science & Technology

    2010-10-21

    REPORT High performance multiwall carbon nanotube bolometers 14. ABSTRACT 16. SECURITY CLASSIFICATION OF: High infrared bolometric photoresponse has...been observed in multiwall carbon nanotube MWCNT films at room temperature. The observed detectivity D in exceeding 3.3 106 cm Hz1/2 /W on MWCNT film...U.S. Army Research Office P.O. Box 12211 Research Triangle Park, NC 27709-2211 15. SUBJECT TERMS carbon nanotube, infrared detector, bolometer

  2. High Performance Multifunctional Carbon Nanotube Fibers

    NASA Astrophysics Data System (ADS)

    Dalton, Alan; Collins, Steve; Munoz, Edgar; Razal, Joselito; Ebron, Von; Ferraris, John; Baughman, Ray

    2003-03-01

    Exploiting the extraordinary properties of carbon nanotubes has remained somewhat elusive due to the inability to process the as produced insoluble soot into functional macroscopic assemblies. To this end we have developed a simple but effective method to produce continuous, homogeneous fibers containing carbon nanotubes having as-spun mechanical properties that compare very favorably to recognized synthetic and natural "super fibers" such as Kevlar and spider silk. By using novel spinning apparatus, spinning solutions, and spinning coagulants, we have spun nanotube fibers having record lengths, record tensile strengths, and having an energy-to-break (toughness) higher than any material that we have found. As an example of the potential multi-functionalities of our fibers, we have fabricated fiber supercapacitors, which we weave into textiles.

  3. Single-walled carbon nanotubes for high-performance electronics.

    PubMed

    Cao, Qing; Han, Shu-jen

    2013-10-07

    Single-walled carbon nanotubes (SWNT) could replace silicon in high-performance electronics with their exceptional electrical properties and intrinsic ultra-thin body. During the past five years, the major focus of this field is gradually shifting from proof-of-concept prototyping in academia to technology development in industry with emphasis on manufacturability and integration issues. This article reviews recent advances, starting with experimental and modeling works that evaluate the potential of adopting SWNTs in ultimately scaled transistors. Techniques to separate nanotubes according to their electronic types and assemble them into aligned arrays are then discussed, followed by a description of the engineering aspects in their implementation in integrated circuits and systems. A concluding discussion provides some perspectives on future challenges and research opportunities.

  4. Imaging Carbon Nanotubes in High Performance Polymer Composites via Magnetic Force Microscope

    NASA Technical Reports Server (NTRS)

    Lillehei, Peter T.; Park, Cheol; Rouse, Jason H.; Siochi, Emilie J.; Bushnell, Dennis M. (Technical Monitor)

    2002-01-01

    Application of carbon nanotubes as reinforcement in structural composites is dependent on the efficient dispersion of the nanotubes in a high performance polymer matrix. The characterization of such dispersion is limited by the lack of available tools to visualize the quality of the matrix/carbon nanotube interaction. The work reported herein demonstrates the use of magnetic force microscopy (MFM) as a promising technique for characterizing the dispersion of nanotubes in a high performance polymer matrix.

  5. High performance transistors via aligned polyfluorene-sorted carbon nanotubes

    SciTech Connect

    Brady, Gerald J.; Joo, Yongho; Singha Roy, Susmit; Gopalan, Padma; Arnold, Michael S.

    2014-02-24

    We evaluate the performance of exceptionally electronic-type sorted, semiconducting, aligned single-walled carbon nanotubes (s-SWCNTs) in field effect transistors (FETs). High on-conductance and high on/off conductance modulation are simultaneously achieved at channel lengths which are both shorter and longer than individual s-SWCNTs. The s-SWCNTs are isolated from heterogeneous mixtures using a polyfluorene-derivative as a selective agent and aligned on substrates via dose-controlled, floating evaporative self-assembly at densities of ∼50 s-SWCNTs μm{sup −1}. At a channel length of 9 μm the s-SWCNTs percolate to span the FET channel, and the on/off ratio and charge transport mobility are 2.2 × 10{sup 7} and 46 cm{sup 2} V{sup −1} s{sup −1}, respectively. At a channel length of 400 nm, a large fraction of the s-SWCNTs directly span the channel, and the on-conductance per width is 61 μS μm{sup −1} and the on/off ratio is 4 × 10{sup 5}. These results are considerably better than previous solution-processed FETs, which have suffered from poor on/off ratio due to spurious metallic nanotubes that bridge the channel. 4071 individual and small bundles of s-SWCNTs are tested in 400 nm channel length FETs, and all show semiconducting behavior, demonstrating the high fidelity of polyfluorenes as selective agents and the promise of assembling s-SWCNTs from solution to create high performance semiconductor electronic devices.

  6. Nickel clusters embedded in carbon nanotubes as high performance magnets.

    PubMed

    Shiozawa, Hidetsugu; Briones-Leon, Antonio; Domanov, Oleg; Zechner, Georg; Sato, Yuta; Suenaga, Kazu; Saito, Takeshi; Eisterer, Michael; Weschke, Eugen; Lang, Wolfgang; Peterlik, Herwig; Pichler, Thomas

    2015-10-13

    Ensembles of fcc nickel nanowires have been synthesized with defined mean sizes in the interior of single-wall carbon nanotubes. The method allows the intrinsic nature of single-domain magnets to emerge with large coercivity as their size becomes as small as the exchange length of nickel. By means of X-ray magnetic circular dichroism we probe electronic interactions at nickel-carbon interfaces where nickel exhibit no hysteresis and size-dependent spin magnetic moment. A manifestation of the interacting two subsystems on a bulk scale is traced in the nanotube's magnetoresistance as explained within the framework of weak localization.

  7. Bonding Unidirectional Carbon Nanotube with Carbon for High Performance

    DTIC Science & Technology

    2015-06-24

    fraction CNT composites with a high level of alignment, low level of CNT waviness and uniform distribution of polymer surrounding the CNTs. This was...accomplished through a process called spray winding. In this process polymer solution was sprayed onto aligned CNT sheets as they were taken up onto a...specific strengths, higher than their carbon fiber composite counterparts. In addition to CNT- polymer matrix composites, the team produced CNT-carbon

  8. Nickel clusters embedded in carbon nanotubes as high performance magnets

    NASA Astrophysics Data System (ADS)

    Shiozawa, Hidetsugu; Briones-Leon, Antonio; Domanov, Oleg; Zechner, Georg; Sato, Yuta; Suenaga, Kazu; Saito, Takeshi; Eisterer, Michael; Weschke, Eugen; Lang, Wolfgang; Peterlik, Herwig; Pichler, Thomas

    2015-10-01

    Ensembles of fcc nickel nanowires have been synthesized with defined mean sizes in the interior of single-wall carbon nanotubes. The method allows the intrinsic nature of single-domain magnets to emerge with large coercivity as their size becomes as small as the exchange length of nickel. By means of X-ray magnetic circular dichroism we probe electronic interactions at nickel-carbon interfaces where nickel exhibit no hysteresis and size-dependent spin magnetic moment. A manifestation of the interacting two subsystems on a bulk scale is traced in the nanotube’s magnetoresistance as explained within the framework of weak localization.

  9. Nickel clusters embedded in carbon nanotubes as high performance magnets

    PubMed Central

    Shiozawa, Hidetsugu; Briones-Leon, Antonio; Domanov, Oleg; Zechner, Georg; Sato, Yuta; Suenaga, Kazu; Saito, Takeshi; Eisterer, Michael; Weschke, Eugen; Lang, Wolfgang; Peterlik, Herwig; Pichler, Thomas

    2015-01-01

    Ensembles of fcc nickel nanowires have been synthesized with defined mean sizes in the interior of single-wall carbon nanotubes. The method allows the intrinsic nature of single-domain magnets to emerge with large coercivity as their size becomes as small as the exchange length of nickel. By means of X-ray magnetic circular dichroism we probe electronic interactions at nickel-carbon interfaces where nickel exhibit no hysteresis and size-dependent spin magnetic moment. A manifestation of the interacting two subsystems on a bulk scale is traced in the nanotube’s magnetoresistance as explained within the framework of weak localization. PMID:26459370

  10. High performance triboelectric nanogenerators with aligned carbon nanotubes.

    PubMed

    Wang, Huan; Shi, Mayue; Zhu, Kai; Su, Zongming; Cheng, Xiaoliang; Song, Yu; Chen, Xuexian; Liao, Zhiqiang; Zhang, Min; Zhang, Haixia

    2016-11-03

    As the essential element of a triboelectric nanogenerator (TENG), friction layers play key roles that determine the device performance, which can be enhanced by material selection and surface modification. In this work, we have embedded aligned carbon nanotubes (CNTs) on the polydimethylsiloxane (PDMS) surface as the effective dielectric layer to donate electrons. This layer not only increases the electron generation for the output, but also shows notable stretchability. The length and the properties of the aligned CNTs can be controlled precisely. Using the 40 μm CNT as an example, the fabricated CNT-PDMS TENG shows an output voltage of 150 V and a current density of 60 mA m(-2), which are 250% and 300% enhancement compared to the TENG using directly doped PDMS/multiwall carbon nanotubes, respectively. The maximum power density of this TENG reaches 4.62 W m(-2) at an external load of 30 MΩ. The TENG has demonstrated superior stability during cyclic measurement of over 12 000 cycles. Besides, the aligned CNT-PDMS film shows superhydrophobicity (154°) and good sheet resistance of 280 Ω sq(-1). This stretchable aligned CNT-PDMS film can be universally utilized as a positive triboelectric layer pairing with polymeric materials such as polyethylene terephthalate, polyimide, PDMS and polytetrafluoroethylene for TENGs. This work provides an effective method of structure design for flexible and stretchable nanogenerators.

  11. Flexible Carbon Nanotube Films for High Performance Strain Sensors

    PubMed Central

    Kanoun, Olfa; Müller, Christian; Benchirouf, Abderahmane; Sanli, Abdulkadir; Dinh, Trong Nghia; Al-Hamry, Ammar; Bu, Lei; Gerlach, Carina; Bouhamed, Ayda

    2014-01-01

    Compared with traditional conductive fillers, carbon nanotubes (CNTs) have unique advantages, i.e., excellent mechanical properties, high electrical conductivity and thermal stability. Nanocomposites as piezoresistive films provide an interesting approach for the realization of large area strain sensors with high sensitivity and low manufacturing costs. A polymer-based nanocomposite with carbon nanomaterials as conductive filler can be deposited on a flexible substrate of choice and this leads to mechanically flexible layers. Such sensors allow the strain measurement for both integral measurement on a certain surface and local measurement at a certain position depending on the sensor geometry. Strain sensors based on carbon nanostructures can overcome several limitations of conventional strain sensors, e.g., sensitivity, adjustable measurement range and integral measurement on big surfaces. The novel technology allows realizing strain sensors which can be easily integrated even as buried layers in material systems. In this review paper, we discuss the dependence of strain sensitivity on different experimental parameters such as composition of the carbon nanomaterial/polymer layer, type of polymer, fabrication process and processing parameters. The insights about the relationship between film parameters and electromechanical properties can be used to improve the design and fabrication of CNT strain sensors. PMID:24915183

  12. Toward high-performance digital logic technology with carbon nanotubes.

    PubMed

    Tulevski, George S; Franklin, Aaron D; Frank, David; Lobez, Jose M; Cao, Qing; Park, Hongsik; Afzali, Ali; Han, Shu-Jen; Hannon, James B; Haensch, Wilfried

    2014-09-23

    The slow-down in traditional silicon complementary metal-oxide-semiconductor (CMOS) scaling (Moore's law) has created an opportunity for a disruptive innovation to bring the semiconductor industry into a postsilicon era. Due to their ultrathin body and ballistic transport, carbon nanotubes (CNTs) have the intrinsic transport and scaling properties to usher in this new era. The remaining challenges are largely materials-related and include obtaining purity levels suitable for logic technology, placement of CNTs at very tight (∼5 nm) pitch to allow for density scaling and source/drain contact scaling. This review examines the potential performance advantages of a CNT-based computing technology, outlines the remaining challenges, and describes the recent progress on these fronts. Although overcoming these issues will be challenging and will require a large, sustained effort from both industry and academia, the recent progress in the field is a cause for optimism that these materials can have an impact on future technologies.

  13. High performance carbon nanotube - polymer nanofiber hybrid fabrics

    NASA Astrophysics Data System (ADS)

    Yildiz, Ozkan; Stano, Kelly; Faraji, Shaghayegh; Stone, Corinne; Willis, Colin; Zhang, Xiangwu; Jur, Jesse S.; Bradford, Philip D.

    2015-10-01

    Stable nanoscale hybrid fabrics containing both polymer nanofibers and separate and distinct carbon nanotubes (CNTs) are highly desirable but very challenging to produce. Here, we report the first instance of such a hybrid fabric, which can be easily tailored to contain 0-100% millimeter long CNTs. The novel CNT - polymer hybrid nonwoven fabrics were created by simultaneously electrospinning nanofibers onto aligned CNT sheets which were drawn and collected on a grounded, rotating mandrel. Due to the unique properties of the CNTs, the hybrids show very high tensile strength, very small pore size, high specific surface area and electrical conductivity. In order to further examine the hybrid fabric properties, they were consolidated under pressure, and also calendered at 70 °C. After calendering, the fabric's strength increased by an order of magnitude due to increased interactions and intermingling with the CNTs. The hybrids are highly efficient as aerosol filters; consolidated hybrid fabrics with a thickness of 20 microns and areal density of only 8 g m-2 exhibited ultra low particulate (ULPA) filter performance. The flexibility of this nanofabrication method allows for the use of many different polymer systems which provides the opportunity for engineering a wide range of nanoscale hybrid materials with desired functionalities.Stable nanoscale hybrid fabrics containing both polymer nanofibers and separate and distinct carbon nanotubes (CNTs) are highly desirable but very challenging to produce. Here, we report the first instance of such a hybrid fabric, which can be easily tailored to contain 0-100% millimeter long CNTs. The novel CNT - polymer hybrid nonwoven fabrics were created by simultaneously electrospinning nanofibers onto aligned CNT sheets which were drawn and collected on a grounded, rotating mandrel. Due to the unique properties of the CNTs, the hybrids show very high tensile strength, very small pore size, high specific surface area and electrical

  14. High-performance supercapacitors based on vertically aligned carbon nanotubes and nonaqueous electrolytes.

    PubMed

    Kim, Byungwoo; Chung, Haegeun; Kim, Woong

    2012-04-20

    We demonstrate the high performance of supercapacitors fabricated with vertically aligned carbon nanotubes and nonaqueous electrolytes such as ionic liquids and conventional organic electrolytes. Specific capacitance, maximum power and energy density of the supercapacitor measured in ionic liquid were ~75 F g(-1), ~987 kW kg(-1) and ~27 W h kg(-1), respectively. The high power performance was consistently indicated by a fast relaxation time constant of 0.2 s. In addition, electrochemical oxidation of the carbon nanotubes improved the specific capacitance (~158 F g(-1)) and energy density (~53 W h kg(-1)). Both high power and energy density could be attributed to the fast ion transport realized by the alignment of carbon nanotubes and the wide operational voltage defined by the ionic liquid. The demonstrated carbon-nanotube- and nonaqueous-electrolyte-based supercapacitors show great potential for the development of high-performance energy storage devices.

  15. High Performance Shape Memory Epoxy/Carbon Nanotube Nanocomposites.

    PubMed

    Liu, Yayun; Zhao, Jun; Zhao, Lingyu; Li, Weiwei; Zhang, Hui; Yu, Xiang; Zhang, Zhong

    2016-01-13

    A series of shape memory nanocomposites based on diglycidyl ether of bisphenol A (DGEBA) E51/methylhexahydrophthalic anhydride (MHHPA)/multiwalled carbon nanotube (MWCNT) with various stoichiometric ratios (rs) of DGEBA/MHHPA from 0.5 to 1.2 and filler contents of 0.25 and 0.75 wt % are fabricated. Their morphology, curing kinetics, phase transition, mechanical properties, thermal conduction, and shape memory behaviors are systematically investigated. The prepared materials show a wide range of glass transition temperatures (Tg) of ca. 65-140 °C, high flexural modulus (E) at room temperature up to ca. 3.0 GPa, high maximum stress (σm) up to ca. 30 MPa, high strain at break (εb) above 10%, and a fast recovery of 32 s. The results indicate that a small amount of MWCNT fillers (0.75 wt %) can significantly increase all three key mechanical properties (E, σm, and εb) at temperatures close to Tg, the recovery rate, and the repetition stability of the shape memory cycles. All of these remarkable advantages make the materials good candidates for the applications in aerospace and other important fields.

  16. High performance carbon nanotube--polymer nanofiber hybrid fabrics.

    PubMed

    Yildiz, Ozkan; Stano, Kelly; Faraji, Shaghayegh; Stone, Corinne; Willis, Colin; Zhang, Xiangwu; Jur, Jesse S; Bradford, Philip D

    2015-10-28

    Stable nanoscale hybrid fabrics containing both polymer nanofibers and separate and distinct carbon nanotubes (CNTs) are highly desirable but very challenging to produce. Here, we report the first instance of such a hybrid fabric, which can be easily tailored to contain 0-100% millimeter long CNTs. The novel CNT - polymer hybrid nonwoven fabrics were created by simultaneously electrospinning nanofibers onto aligned CNT sheets which were drawn and collected on a grounded, rotating mandrel. Due to the unique properties of the CNTs, the hybrids show very high tensile strength, very small pore size, high specific surface area and electrical conductivity. In order to further examine the hybrid fabric properties, they were consolidated under pressure, and also calendered at 70 °C. After calendering, the fabric's strength increased by an order of magnitude due to increased interactions and intermingling with the CNTs. The hybrids are highly efficient as aerosol filters; consolidated hybrid fabrics with a thickness of 20 microns and areal density of only 8 g m(-2) exhibited ultra low particulate (ULPA) filter performance. The flexibility of this nanofabrication method allows for the use of many different polymer systems which provides the opportunity for engineering a wide range of nanoscale hybrid materials with desired functionalities.

  17. Gamma-irradiated carbon nanotube yarn as substrate for high-performance fiber supercapacitors.

    PubMed

    Su, Fenghua; Miao, Menghe; Niu, Haitao; Wei, Zhixiang

    2014-02-26

    As an electrical double layer capacitor, dry-spun carbon nanotube yarn possesses relatively low specific capacitance. This can be significantly increased as a result of the pseudocapacitance of functional groups on the carbon nanotubes developed by oxidation using a gamma irradiation treatment in the presence of air. When coated with high-performance polyaniline nanowires, the gamma-irradiated carbon nanotube yarn acts as a high-strength reinforcement and a high-efficiency current collector in two-ply yarn supercapacitors for transporting charges generated along the long electrodes. The resulting supercapacitors demonstrate excellent electrochemical performance, cycle stability, and resistance to folding-unfolding that are required in wearable electronic textiles.

  18. Preparation of Tunable 3D Pillared Carbon Nanotube-Graphene Networks for High-Performance Capacitance

    DTIC Science & Technology

    2011-01-01

    puter modeling has predicted that such a 3D pillared VACNT graphene structure can be used for efficient hydrogen storage after being doped with...Pillared Carbon Nanotube Graphene Networks for High-Performance Capacitance Feng Du,†,§ Dingshan Yu,†,§ Liming Dai,†,* S. Ganguli,‡ V. Varshney,‡ and A...nanotubes (CNTs) and two-dimensional (2D) single-atomic layer graphene , have been demonstrated to show superior thermal, electrical, and mechanical

  19. Controlled Synthesis of Core-Shell Carbon@MoS2 Nanotube Sponges as High-Performance Battery Electrodes.

    PubMed

    Wang, Yunsong; Ma, Zhimin; Chen, Yijun; Zou, Mingchu; Yousaf, Muhammad; Yang, Yanbing; Yang, Liusi; Cao, Anyuan; Han, Ray P S

    2016-12-01

    Heterogeneous inorganic nanotube structures consisting of multiwalled carbon nanotubes coated by long, continuous MoS2 sheets with tunable sheet number are synthesized using a carbon-nanotube sponge as a template. The resulting 3D porous hybrid sponges have potential applications as high-performance freestanding anodes for Li-ion batteries with excellent specific capacity and cycling stability.

  20. Arrays of single-walled carbon nanotubes with full surface coverage for high-performance electronics.

    PubMed

    Cao, Qing; Han, Shu-jen; Tulevski, George S; Zhu, Yu; Lu, Darsen D; Haensch, Wilfried

    2013-03-01

    Single-walled carbon nanotubes have exceptional electronic properties and have been proposed as a replacement for silicon in applications such as low-cost thin-film transistors and high-performance logic devices. However, practical devices will require dense, aligned arrays of electronically pure nanotubes to optimize performance, maximize device packing density and provide sufficient drive current (or power output) for each transistor. Here, we show that aligned arrays of semiconducting carbon nanotubes can be assembled using the Langmuir-Schaefer method. The arrays have a semiconducting nanotube purity of 99% and can fully cover a surface with a nanotube density of more than 500 tubes/µm. The nanotube pitch is self-limited by the diameter of the nanotube plus the van der Waals separation, and the intrinsic mobility of the nanotubes is preserved after array assembly. Transistors fabricated using this approach exhibit significant device performance characteristics with a drive current density of more than 120 µA µm(-1), transconductance greater than 40 µS µm(-1) and on/off ratios of ∼1 × 10(3).

  1. Carbon nanotube high-performance logic technology - challenges and current progress

    NASA Astrophysics Data System (ADS)

    Han, Shu-Jen

    2015-03-01

    In the last four decades, we have witnessed a tremendous information technology revolution originated from the relentless scaling of Si complementary metal-oxide semiconductor (CMOS) devices. CMOS scaling provides ever-improved transistor performance, density, power and cost, and will continue to bring new applications and functions to our daily life. However, the conventional homogeneous scaling of silicon devices has become very difficult, firstly due to the unsatisfactory electrostatic control from the gate dielectric. In addition, as we look forward to the technology nodes with sub-10 nm channel length, non-Si based channel materials will be required to provide continuous carrier velocity enhancement when the conventional strained-Si techniques run out of steam. Single-walled carbon nanotubes are promising to replace silicon as the channel material for high-performance electronics near the end of silicon scaling roadmap, with their superb electrical properties, intrinsic ultrathin body, and nearly transparent contact with certain metals. This talk discusses recent advances in modeling and experimental works that reveal the properties and potential of ultra-scaled nanotube transistors, separation and assembly techniques for forming nanotube arrays with high semiconducting nanotube purity and tight pitch separation, and engineering aspects of their implementation in integrated circuits and functional systems. A concluding discussion highlights most significant challenges from technology points of view, and provides perspectives on the future of carbon nanotube based nanoelectronics.

  2. En route toward high performance electronics based on single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Cao, Qing

    2014-06-01

    Single-walled carbon nanotubes (SWNT) could replace silicon in high-performance electronics with their exceptional electrical properties and intrinsic ultra-thin body. During the past five years, the major focus of this field is gradually shifting from proof-of-concept prototyping in academia to technology development in industry with emphasis on manufacturability and integration issues. Here we will review some most significant recent advances, with focus on assembling high purity semiconducting SWNTs into well aligned arrays. Future challenges and research opportunities in this field will also be discussed.

  3. Carbon nanotube bundles/polystyrene composites as high-performance flexible thermoelectric materials

    NASA Astrophysics Data System (ADS)

    Suemori, Kouji; Watanabe, Yuichi; Hoshino, Satoshi

    2015-03-01

    Lightweight and flexible thermoelectric devices consisting of carbon nanotube (CNT)-based materials have the potential to be used for the various applications, such as energy harvesting from the low-temperature waste heat that exists ubiquitously in living areas. Because high-performance CNT-based materials are crucial for the broad-ranging employment of CNT-based thermoelectric devices, considerable efforts are being made to improve the power-generation capability of CNT-based thermoelectric materials. Here, we report high-performance thermoelectric composites consisting of CNT bundles and polystyrene fabricated by a planetary ball milling-based dispersion technique, which allows for the direct dispersion of the CNT bundles within the polystyrene matrix without causing the disaggregation of the bundled CNTs into individual ones. The CNT-bundles/polystyrene composites reported here exhibit a power factor of 413 μW/K2.m.

  4. High-performance carbon nanotube-implanted mesoporous carbon spheres for supercapacitors with low series resistance

    SciTech Connect

    Yi, Bin; Chen, Xiaohua; Guo, Kaimin; Xu, Longshan; Chen, Chuansheng; Yan, Haimei; Chen, Jianghua

    2011-11-15

    Research highlights: {yields} CNTs-implanted porous carbon spheres are prepared by using gelatin as soft template. {yields} Homogeneously distributed CNTs form a well-develop network in carbon spheres. {yields} CNTs act as a reinforcing backbone assisting the formation of pore structure. {yields} CNTs improve electrical conductivity and specific capacitance of supercapacitor. -- Abstract: Carbon nanotube-implanted mesoporous carbon spheres were prepared by an easy polymerization-induced colloid aggregation method using gelatin as a soft template. Scanning electron microscopy, transmission electron microscopy and nitrogen adsorption-desorption measurements reveal that the materials are mesoporous carbon spheres, with a diameter of {approx}0.5-1.0 {mu}m, a specific surface area of 284 m{sup 2}/g and average pore size of 3.9 nm. Using the carbon nanotube-implanted mesoporous carbon spheres as electrode material for supercapacitors in an aqueous electrolyte solution, a low equivalent series resistance of 0.83 {Omega} cm{sup 2} and a maximum specific capacitance of 189 F/g with a measured power density of 8.7 kW/kg at energy density of 6.6 Wh/kg are obtained.

  5. Three-dimensional porous carbon nanotube sponges for high-performance anodes of microbial fuel cells

    NASA Astrophysics Data System (ADS)

    Erbay, Celal; Yang, Gang; de Figueiredo, Paul; Sadr, Reza; Yu, Choongho; Han, Arum

    2015-12-01

    Highly-porous, light-weight, and inexpensive three-dimensional (3D) sponges consisting of interconnected carbon nanotubes (CNTs) without base materials are synthesized with a facile and scalable one-step chemical vapor deposition process as anode of microbial fuel cells (MFCs). The MFCs generates higher power densities of 2150 W m-3 (per anode volume) or 170 W m-3 (per anode chamber volume), comparable to those of commercial 3D carbon felt electrodes under the same conditions. The high performances are due to excellent charge transfer between CNTs and microbes owing to 13 times lower charge transfer resistance compared to that of carbon felt. The material cost of producing these CNT sponge estimates to be ∼0.1/gCNT, significantly lower than that of other methods. In addition, the high production rate of about 3.6 g h-1 compared to typical production rate of 0.02 g h-1 of other CNT-based materials makes this process economically viable. The one-step synthesis method allowing self-assembly of 3D CNT sponges as they grow is low cost and scalable, making this a promising method for manufacturing high-performance anodes of MFCs, with broad applicability to microbial electrochemical systems in general.

  6. High performance electrochemical and electrothermal artificial muscles from twist-spun carbon nanotube yarn

    NASA Astrophysics Data System (ADS)

    Lee, Jae Ah; Baughman, Ray H.; Kim, Seon Jeong

    2015-04-01

    High performance torsional and tensile artificial muscles are described, which utilize thermally- or electrochemically-induced volume changes of twist-spun, guest-filled, carbon nanotube (CNT) yarns. These yarns were prepared by incorporating twist in carbon nanotube sheets drawn from spinnable CNT forests. Inserting high twist into the CNT yarn results in yarn coiling, which can dramatically amplify tensile stroke and work capabilities compared with that for the non-coiled twisted yarn. When electrochemically driven in a liquid electrolyte, these artificial muscles can generate a torsional rotation per muscle length that is over 1000 times higher than for previously reported torsional muscles. All-solid-state torsional electrochemical yarn muscles have provided a large torsional muscle stroke (53° per mm of yarn length) and a tensile stroke of up to 1.3% when lifting loads that are ~25 times heavier than can be lifted by the same diameter human skeletal muscle. Over a million torsional and tensile actuation cycles have been demonstrated for thermally powered CNT hybrid yarns muscles filled with paraffin wax, wherein a muscle spins a rotor at an average 11,500 revolutions/minute or delivers 3% tensile contraction at 1200 cycles/minute. At lower actuation rates, these thermally powered muscles provide tensile strokes of over 10%.

  7. High-performance hybrid carbon nanotube fibers for wearable energy storage.

    PubMed

    Lu, Zan; Chao, Yunfeng; Ge, Yu; Foroughi, Javad; Zhao, Yong; Wang, Caiyun; Long, Hairu; Wallace, Gordon G

    2017-03-07

    Wearable energy storage devices are of practical interest, but few have been commercially exploited. Production of electrodes with extended cycle life, as well as high energy and power densities, coupled with flexibility, remains a challenge. Herein, we have demonstrated the development of a high-performance hybrid carbon nanotube (CNT) fiber-based supercapacitor for the first time using conventional wet-spinning processes. Manganese dioxide (MnO2) nanoflakes were deposited onto the as-prepared CNT fibers by electrodeposition to form highly flexible nanocomposites fibers. As-prepared fibers were characterized by electron microscopy, electrical, mechanical, and electrochemical measurements. It was found that the specific capacitance was over 152 F g(-1) (156 F cm(-3)), which is about 500% higher than the multi-walled carbon nanotube/MnO2 yarn-based supercapacitors. The measured energy density was 14.1 Wh kg(-1) at a power density of 202 W kg(-1). These values are 232% and 32% higher than the energy density and power density of MWNT/MnO2 yarn-based supercapacitor, respectively. It was found that the cyclic retention ability was more stable, revealing a 16% increase after 10 000 cycles. Such substantial enhancements of key properties of the hybrid material can be associated with the synergy of CNT and MnO2 nanoparticles in the fiber structure. The use of wet-spun hybrid CNT for fiber-based supercapacitors has been demonstrated.

  8. Fabrication of graphene foam supported carbon nanotube/polyaniline hybrids for high-performance supercapacitor applications

    NASA Astrophysics Data System (ADS)

    Yang, Hongxia; Wang, Nan; Xu, Qun; Chen, Zhimin; Ren, Yumei; Razal, Joselito M.; Chen, Jun

    2014-12-01

    A large-scale, high-powered energy storage system is crucial for addressing the energy problem. The development of high-performance materials is a key issue in realizing the grid-scale applications of energy-storage devices. In this work, we describe a simple and scalable method for fabricating hybrids (graphene-pyrrole/carbon nanotube-polyaniline (GPCP)) using graphene foam as the supporting template. Graphene-pyrrole (G-Py) aerogels are prepared via a green hydrothermal route from two-dimensional materials such as graphene sheets, while a carbon nanotube/polyaniline (CNT/PANI) composite dispersion is obtained via the in situ polymerization method. The functional nanohybrid materials of GPCP can be assembled by simply dipping the prepared G-py aerogels into the CNT/PANI dispersion. The morphology of the obtained GPCP is investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), which revealed that the CNT/PANI was uniformly deposited onto the surfaces of the graphene. The as-synthesized GPCP maintains its original three-dimensional hierarchical porous architecture, which favors the diffusion of the electrolyte ions into the inner region of the active materials. Such hybrid materials exhibit significant specific capacitance of up to 350 F g-1, making them promising in large-scale energy-storage device applications.

  9. Multiwalled carbon nanotube/polydimethylsiloxane composite films as high performance flexible electric heating elements

    SciTech Connect

    Yan, Jing; Jeong, Young Gyu

    2014-08-04

    High performance elastomeric electric heating elements were prepared by incorporating various contents of pristine multiwalled carbon nanotube (MWCNT) in polydimethylsiloxane (PDMS) matrix by using an efficient solution-casting and curing technique. The pristine MWCNTs were identified to be uniformly dispersed in the PDMS matrix and the electrical percolation of MWCNTs was evaluated to be at ∼0.27 wt. %, where the electrical resistivity of the MWCNT/PDMS composite films dropped remarkably. Accordingly, the composite films with higher MWCNT contents above 0.3 wt. % exhibit excellent electric heating performance in terms of temperature response rapidity and electric energy efficiency at constant applied voltages. In addition, the composite films, which were thermally stable up to 250 °C, showed excellent heating-cooling cyclic performance, which was associated with operational stability in actual electric heating applications.

  10. Winding aligned carbon nanotube composite yarns into coaxial fiber full batteries with high performances.

    PubMed

    Weng, Wei; Sun, Qian; Zhang, Ye; Lin, Huijuan; Ren, Jing; Lu, Xin; Wang, Min; Peng, Huisheng

    2014-06-11

    Inspired by the fantastic and fast-growing wearable electronics such as Google Glass and Apple iWatch, matchable lightweight and weaveable energy storage systems are urgently demanded while remaining as a bottleneck in the whole technology. Fiber-shaped energy storage devices that can be woven into electronic textiles may represent a general and effective strategy to overcome the above difficulty. Here a coaxial fiber lithium-ion battery has been achieved by sequentially winding aligned carbon nanotube composite yarn cathode and anode onto a cotton fiber. Novel yarn structures are designed to enable a high performance with a linear energy density of 0.75 mWh cm(-1). A wearable energy storage textile is also produced with an areal energy density of 4.5 mWh cm(-2).

  11. Building robust carbon nanotube-interweaved-nanocrystal architecture for high-performance anode materials.

    PubMed

    Jia, Xilai; Cheng, Yanhua; Lu, Yunfeng; Wei, Fei

    2014-09-23

    Rational design of electrode materials is essential but still a challenge for lithium-ion batteries. Herein, we report the design and fabrication of a class of nanocomposite architecture featured by hierarchically structured composite particles that are built from iron oxide nanocrystals and carbon nanotubes. An aerosol spray drying process was used to synthesize this architecture. Such nanoarchitecture enhanced the ion transport and conductivity that are required for high-power anodes. The large volume changes of the anodes during lithium insertion and extraction are accommodated by the particle's resilience and internal porosity. High reversible capacities, excellent rate capability, and stable performance are attained. The synthesis process is simple and broadly applicable, providing a general approach toward high-performance energy storage materials.

  12. Hybrid Films of Graphene and Carbon Nanotubes for High Performance Chemical and Temperature Sensing Applications.

    PubMed

    Tung, Tran Thanh; Pham-Huu, Cuong; Janowska, Izabela; Kim, TaeYoung; Castro, Mickael; Feller, Jean-Francois

    2015-07-01

    A hybrid composite material of graphene and carbon nanotube (CNT) for high performance chemical and temperature sensors is reported. Integration of 1D and 2D carbon materials into hybrid carbon composites is achieved by coupling graphene and CNT through poly(ionic liquid) (PIL) mediated-hybridization. The resulting CNT/PIL/graphene hybrid materials are explored as active materials in chemical and temperature sensors. For chemical sensing application, the hybrid composite is integrated into a chemo-resistive sensor to detect a general class of volatile organic compounds. Compared with the graphene-only devices, the hybrid film device showed an improved performance with high sensitivity at ppm level, low detection limit, and fast signal response/recovery. To further demonstrate the potential of the hybrid films, a temperature sensor is fabricated. The CNT/PIL/graphene hybrid materials are highly responsive to small temperature gradient with fast response, high sensitivity, and stability, which may offer a new platform for the thermoelectric temperature sensors.

  13. Polymer-assisted direct deposition of uniform carbon nanotube bundle networks for high performance transparent electrodes.

    PubMed

    Hellstrom, Sondra L; Lee, Hang Woo; Bao, Zhenan

    2009-06-23

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

  14. Three-dimensional carbon nanotube-textile anode for high-performance microbial fuel cells.

    PubMed

    Xie, Xing; Hu, Liangbing; Pasta, Mauro; Wells, George F; Kong, Desheng; Criddle, Craig S; Cui, Yi

    2011-01-12

    Microbial fuel cells (MFCs) harness the metabolism of microorganisms, converting chemical energy into electrical energy. Anode performance is an important factor limiting the power density of MFCs for practical application. Improving the anode design is thus important for enhancing the MFC performance, but only a little development has been reported. Here, we describe a biocompatible, highly conductive, two-scale porous anode fabricated from a carbon nanotube-textile (CNT-textile) composite for high-performance MFCs. The macroscale porous structure of the intertwined CNT-textile fibers creates an open 3D space for efficient substrate transport and internal colonization by a diverse microflora, resulting in a 10-fold-larger anolyte-biofilm-anode interfacial area than the projective surface area of the CNT-textile. The conformally coated microscale porous CNT layer displays strong interaction with the microbial biofilm, facilitating electron transfer from exoelectrogens to the CNT-textile anode. An MFC equipped with a CNT-textile anode has a 10-fold-lower charge-transfer resistance and achieves considerably better performance than one equipped with a traditional carbon cloth anode: the maximum current density is 157% higher, the maximum power density is 68% higher, and the energy recovery is 141% greater.

  15. High performance carbon nanocomposites for ultracapacitors

    DOEpatents

    Lu, Wen

    2012-10-02

    The present invention relates to composite electrodes for electrochemical devices, particularly to carbon nanotube composite electrodes for high performance electrochemical devices, such as ultracapacitors.

  16. Designing the Interface of Carbon Nanotube/Biomaterials for High-Performance Ultra-Broadband Photodetection.

    PubMed

    Gong, Youpin; Adhikari, Puja; Liu, Qingfeng; Wang, Ti; Gong, Maogang; Chan, Wai-Lun; Ching, Wai-Yim; Wu, Judy

    2017-03-29

    Inorganic/biomolecule nanohybrids can combine superior electronic and optical properties of inorganic nanostructures and biomolecules for optoelectronics with performance far surpassing that achievable in conventional materials. The key toward a high-performance inorganic/biomolecule nanohybrid is to design their interface based on the electronic structures of the constituents. A major challenge is the lack of knowledge of most biomolecules due to their complex structures and composition. Here, we first calculated the electronic structure and optical properties of one of the cytochrome c (Cyt c) macromolecules (PDB ID: 1HRC ) using ab initio OLCAO method, which was followed by experimental confirmation using ultraviolet photoemission spectroscopy. For the first time, the highest occupied molecular orbital and lowest unoccupied molecular orbital energy levels of Cyt c, a well-known electron transport chain in biological systems, were obtained. On the basis of the result, pairing the Cyt c with semiconductor single-wall carbon nanotubes (s-SWCNT) was predicted to have a favorable band alignment and built-in electrical field for exciton dissociation and charge transfer across the s-SWCNT/Cyt c heterojunction interface. Excitingly, photodetectors based on the s-SWCNT/Cyt c heterojunction nanohybrids demonstrated extraordinary ultra-broadband (visible light to infrared) responsivity (46-188 A W(-1)) and figure-of-merit detectivity D* (1-6 × 10(10) cm Hz(1/2) W(-1)). Moreover, these devices can be fabricated on transparent flexible substrates by a low-lost nonvacuum method and are stable in air. These results suggest that the s-SWCNT/biomolecule nanohybrids may be promising for the development of CNT-based ultra-broadband photodetectors.

  17. High-Performance Ttransparent and Stretchable All-Solid Supercapacitors Based on Highly Aligned Carbon Nanotube Sheets

    DTIC Science & Technology

    2014-01-09

    the cured piece. A gel containing poly(vinyl alcohol) powder (10 g) and H3PO4 (10 g) in water (100 mL) was used as the solid electrolyte . The gel...High-performance transparent and stretchable all- solid supercapacitors based on highly aligned carbon nanotube sheets Tao Chen1, Huisheng Peng2...stretchable all- solid supercapacitors with a good stability were developed. A transmittance up to 75% at the wavelength of 550 nmwas achieved for a

  18. High-performance two-ply yarn supercapacitors based on carbon nanotubes and polyaniline nanowire arrays.

    PubMed

    Wang, Kai; Meng, Qinghai; Zhang, Yajie; Wei, Zhixiang; Miao, Menghe

    2013-03-13

    Fine count two-ply yarn supercapacitors are constructed from carbon nanotube yarns and polyaniline nanowires. The thread-like supercapacitor possess excellent electrochemical capacity and are very strong and flexible. When being woven or knitted into wearable electronic devices, alone or in combination with conventional textile yarns, the two-ply yarn supercapacitors can be flexed and stretched repeatedly without significant loss of capacitance.

  19. High-performance partially aligned semiconductive single-walled carbon nanotube transistors achieved with a parallel technique.

    PubMed

    Wang, Yilei; Pillai, Suresh Kumar Raman; Chan-Park, Mary B

    2013-09-09

    Single-walled carbon nanotubes (SWNTs) are widely thought to be a strong contender for next-generation printed electronic transistor materials. However, large-scale solution-based parallel assembly of SWNTs to obtain high-performance transistor devices is challenging. SWNTs have anisotropic properties and, although partial alignment of the nanotubes has been theoretically predicted to achieve optimum transistor device performance, thus far no parallel solution-based technique can achieve this. Herein a novel solution-based technique, the immersion-cum-shake method, is reported to achieve partially aligned SWNT networks using semiconductive (99% enriched) SWNTs (s-SWNTs). By immersing an aminosilane-treated wafer into a solution of nanotubes placed on a rotary shaker, the repetitive flow of the nanotube solution over the wafer surface during the deposition process orients the nanotubes toward the fluid flow direction. By adjusting the nanotube concentration in the solution, the nanotube density of the partially aligned network can be controlled; linear densities ranging from 5 to 45 SWNTs/μm are observed. Through control of the linear SWNT density and channel length, the optimum SWNT-based field-effect transistor devices achieve outstanding performance metrics (with an on/off ratio of ~3.2 × 10(4) and mobility 46.5 cm(2) /Vs). Atomic force microscopy shows that the partial alignment is uniform over an area of 20 × 20 mm(2) and confirms that the orientation of the nanotubes is mostly along the fluid flow direction, with a narrow orientation scatter characterized by a full width at half maximum (FWHM) of <15° for all but the densest film, which is 35°. This parallel process is large-scale applicable and exploits the anisotropic properties of the SWNTs, presenting a viable path forward for industrial adoption of SWNTs in printed, flexible, and large-area electronics.

  20. High-performance carbon nanotube thin-film transistors on flexible paper substrates

    SciTech Connect

    Liu, Na; Yun, Ki Nam; Yu, Hyun-Yong; Lee, Cheol Jin; Shim, Joon Hyung

    2015-03-09

    Single-walled carbon nanotubes (SWCNTs) are promising materials as active channels for flexible transistors owing to their excellent electrical and mechanical properties. However, flexible SWCNT transistors have never been realized on paper substrates, which are widely used, inexpensive, and recyclable. In this study, we fabricated SWCNT thin-film transistors on photo paper substrates. The devices exhibited a high on/off current ratio of more than 10{sup 6} and a field-effect mobility of approximately 3 cm{sup 2}/V·s. The proof-of-concept demonstration indicates that SWCNT transistors on flexible paper substrates could be applied as low-cost and recyclable flexible electronics.

  1. High performance dye-sensitized solar cell based on hydrothermally deposited multiwall carbon nanotube counter electrode

    NASA Astrophysics Data System (ADS)

    Siriroj, Sumeth; Pimanpang, Samuk; Towannang, Madsakorn; Maiaugree, Wasan; Phumying, Santi; Jarernboon, Wirat; Amornkitbamrung, Vittaya

    2012-06-01

    Conductive glass was coated with multiwall carbon nanotubes (MWCNTs) by a hydrothermal method. MWCNTs films were subsequently used as dye-sensitized solar cell (DSSC) counter electrodes. The performance of hydrothermal MWCNT DSSC was ˜2.37%. After film annealing in an Ar atmosphere, annealed-hydrothermal MWCNT (AHT-CNT) DSSC efficiency was significantly increased to ˜7.66%, in comparison to ˜8.01% for sputtered-Pt DSSC. Improvement of AHT-CNT DSSC performance is attributed to a decrease in charge-transfer resistance from 1500 Ω to 30 Ω as observed by electrochemical impedance spectroscopy.

  2. Transparent and flexible high-performance supercapacitors based on single-walled carbon nanotube films

    NASA Astrophysics Data System (ADS)

    Kanninen, Petri; Dang Luong, Nguyen; Hoang Sinh, Le; Anoshkin, Ilya V.; Tsapenko, Alexey; Seppälä, Jukka; Nasibulin, Albert G.; Kallio, Tanja

    2016-06-01

    Transparent and flexible energy storage devices have garnered great interest due to their suitability for display, sensor and photovoltaic applications. In this paper, we report the application of aerosol synthesized and dry deposited single-walled carbon nanotube (SWCNT) thin films as electrodes for an electrochemical double-layer capacitor (EDLC). SWCNT films exhibit extremely large specific capacitance (178 F g-1 or 552 μF cm-2), high optical transparency (92%) and stability for 10 000 charge/discharge cycles. A transparent and flexible EDLC prototype is constructed with a polyethylene casing and a gel electrolyte.

  3. High-performance carbon-nanotube-based complementary field-effect-transistors and integrated circuits with yttrium oxide

    SciTech Connect

    Liang, Shibo; Zhang, Zhiyong Si, Jia; Zhong, Donglai; Peng, Lian-Mao

    2014-08-11

    High-performance p-type carbon nanotube (CNT) transistors utilizing yttrium oxide as gate dielectric are presented by optimizing oxidization and annealing processes. Complementary metal-oxide-semiconductor (CMOS) field-effect-transistors (FETs) are then fabricated on CNTs, and the p- and n-type devices exhibit symmetrical high performances, especially with low threshold voltage near to zero. The corresponding CMOS CNT inverter is demonstrated to operate at an ultra-low supply voltage down to 0.2 V, while displaying sufficient voltage gain, high noise margin, and low power consumption. Yttrium oxide is proven to be a competitive gate dielectric for constructing high-performance CNT CMOS FETs and integrated circuits.

  4. Graphene Carbon Nanotube Carpets Grown Using Binary Catalysts for High-Performance Lithium-Ion Capacitors.

    PubMed

    Salvatierra, Rodrigo Villegas; Zakhidov, Dante; Sha, Junwei; Kim, Nam Dong; Lee, Seoung-Ki; Raji, Abdul-Rahman O; Zhao, Naiqin; Tour, James M

    2017-03-28

    Here we show that a versatile binary catalyst solution of Fe3O4/AlOx nanoparticles enables homogeneous growth of single to few-walled carbon nanotube (CNT) carpets from three-dimensional carbon-based substrates, moving past existing two-dimensional limited growth methods. The binary catalyst is composed of amorphous AlOx nanoclusters over Fe3O4 crystalline nanoparticles, facilitating the creation of seamless junctions between the CNTs and the underlying carbon platform. The resulting graphene-CNT (GCNT) structure is a high-density CNT carpet ohmically connected to the carbon substrate, an important feature for advanced carbon electronics. As a demonstration of the utility of this approach, we use GCNTs as anodes and cathodes in binder-free lithium-ion capacitors, producing stable devices with high-energy densities (∼120 Wh kg(-1)), high-power density capabilities (∼20,500 W kg(-1) at 29 Wh kg(-1)), and a large operating voltage window (4.3 to 0.01 V).

  5. High-performance transparent and stretchable all-solid supercapacitors based on highly aligned carbon nanotube sheets

    PubMed Central

    Chen, Tao; Peng, Huisheng; Durstock, Michael; Dai, Liming

    2014-01-01

    By using highly aligned carbon nanotube (CNT) sheets of excellent optical transmittance and mechanical stretchability as both the current collector and active electrode, high-performance transparent and stretchable all-solid supercapacitors with a good stability were developed. A transmittance up to 75% at the wavelength of 550 nm was achieved for a supercapacitor made from a cross-over assembly of two single-layer CNT sheets. The transparent supercapacitor has a specific capacitance of 7.3 F g−1 and can be biaxially stretched up to 30% strain without any obvious change in electrochemical performance even over hundreds stretching cycles. PMID:24402400

  6. Three-dimensional graphene-carbon nanotube hybrid for high-performance enzymatic biofuel cells.

    PubMed

    Prasad, Kenath Priyanka; Chen, Yun; Chen, Peng

    2014-03-12

    Enzymatic biofuel cells (EBFCs) are promising renewable and implantable power sources. However, their power output is often limited by inefficient electron transfer between the enzyme molecules and the electrodes, hindered mass transport, low conductivity, and small active surface area of the electrodes. To tackle these issues, we herein demonstrated a novel EBFC equipped with enzyme-functionalized 3D graphene-single walled carbon nanotubes (SWCNTs) hybrid electrodes using the naturally abundant glucose as the fuel and oxygen as the oxidizer. Such EBFCs, with high stability, can nearly attain the theoretical limit of open circuit voltage (∼1.2 V) and a high power density ever reported (2.27 ± 0.11 mW cm(-2)).

  7. Multiwalled carbon nanotubes anchored with maghemite nanocrystals for high-performance lithium storage

    SciTech Connect

    Wu, Ping Xie, Kongwei; Xu, Xiali; Li, Jianping; Tang, Yawen; Zhou, Yiming Lu, Tianhong

    2015-04-15

    Highlights: • γ-Fe{sub 2}O{sub 3} nanocrystals uniformly anchored on MWCNT via facile layer-by-layer technique. • The hybrid exhibits enhanced structural stability and charge transport capability. • Superior lithium storage performance by virtue of unique structural characteristics. - Abstract: In this paper, we have anchored maghemite (γ-Fe{sub 2}O{sub 3}) nanocrystals compactly and uniformly on multiwalled carbon nanotubes (MWCNT) via a polyelectrolyte-assisted layer-by-layer assembly approach based on electrostatic attraction. When evaluated as an anode for lithium-ion batteries (LIBs), the as-synthesized MWCNT-γ-Fe{sub 2}O{sub 3} nanohybrid displays high reversible capacities, remarkable cycling stability, and magnificent high rate capability, facilitating its application as an advanced anode for high-energy, long-life, and high-power LIBs.

  8. Inkjet printing of flexible high-performance carbon nanotube transparent conductive films by ``coffee ring effect''

    NASA Astrophysics Data System (ADS)

    Shimoni, Allon; Azoubel, Suzanna; Magdassi, Shlomo

    2014-09-01

    Transparent and flexible conductors are a major component in many modern optoelectronic devices, such as touch screens for smart phones, displays, and solar cells. Carbon nanotubes (CNTs) offer a good alternative to commonly used conductive materials, such as metal oxides (e.g. ITO) for flexible electronics. The production of transparent conductive patterns, and arrays composed of connected CNT ``coffee rings'' on a flexible substrate poly(ethylene terephthalate), has been reported. Direct patterning is achieved by inkjet printing of an aqueous dispersion of CNTs, which self-assemble at the rim of evaporating droplets. After post-printing treatment with hot nitric acid, the obtained TCFs are characterized by a sheet resistance of 156 Ω sq-1 and transparency of 81% (at 600 nm), which are the best reported values obtained by inkjet printing of conductive CNTs. This makes such films very promising as transparent conductors for various electronic devices, as demonstrated by using an electroluminescent device.

  9. High-performance flexible nanoporous Si-carbon nanotube paper anodes for micro-battery applications

    NASA Astrophysics Data System (ADS)

    Biserni, Erika; Scarpellini, Alice; Li Bassi, Andrea; Bruno, Paola; Zhou, Yun; Xie, Ming

    2016-06-01

    Nanoporous Si has been grown by pulsed laser deposition on a free-standing carbon nanotube (CNT) paper sheet for micro-battery anodes. The Si deposition shows conformal coverage on the CNT paper, and the Si-CNT paper anodes demonstrate high areal capacity of ˜1000 μAh cm-2 at a current density of 54 μA cm-2, while 69% of its initial capacity is preserved when the current density is increased by a factor 10. Excellent stability without capacity decay up to 1000 cycles at a current density of 1080 μA cm-2 is also demonstrated. After bending along the diameter of the circular paper disc many times, the Si-CNT paper anodes preserve the same morphology and show promising electrochemical performance, indicating that nanoporous Si-CNT paper anodes can find application for flexible micro-batteries.

  10. Control of geometrical properties of carbon nanotube electrodes towards high-performance microbial fuel cells

    NASA Astrophysics Data System (ADS)

    Erbay, Celal; Pu, Xiong; Choi, Woongchul; Choi, Mi-Jin; Ryu, Yeontack; Hou, Huijie; Lin, Furong; de Figueiredo, Paul; Yu, Choongho; Han, Arum

    2015-04-01

    In microbial fuel cells (MFCs), physical and electrochemical interactions between microbes and electrode surfaces are critical to performance. Nanomaterial-based electrodes have shown promising performances, however their unique characteristics have not been fully utilized. The developed electrodes here consist of multi-wall carbon nanotubes (MWCNTs) directly grown in the radial direction from the wires of stainless steel (SS) meshes, providing extremely large three-dimensional surfaces while ensuring minimal ohmic loss between CNTs and SS meshes, fully utilizing the advantages of CNTs. Systematic studies on how different lengths, packing densities, and surface conditions of CNTs affect MFC power output revealed that long and loosely packed CNTs without any amorphous carbon show the highest power production performance. The power density of this anode is 7.4-fold higher compared to bare carbon cloth, which is the highest reported improvement for MFCs with nanomaterial-decorated electrodes. The results of this study offer great potential for advancing the development of microbial electrochemical systems by providing a highly efficient nanomaterial-based electrode that delivers large surface area, high electrochemical activity, and minimum ohmic loss, as well as provide design principles for next-generation nanomaterial-based electrodes that can be broadly applicable for highly efficient microbial electrochemical cells.

  11. Photopolymerization of Diacetylene on Aligned Multiwall Carbon Nanotube Microfibers for High-Performance Energy Devices.

    PubMed

    Ulaganathan, Mani; Hansen, Reinack Varghese; Drayton, Nateisha; Hingorani, Hardik; Kutty, R Govindan; Joshi, Hrishikesh; Sreejith, Sivaramapanicker; Liu, Zheng; Yang, Jinglei; Zhao, Yanli

    2016-12-07

    Linear two-dimensional materials have recently attracted an intense interest for supercapacitors because of their potential uses as electrodes in next-generation wearable electronics. However, enhancing the electrochemical properties of these materials without complicated structural modifications remains a challenge. Herein, we present the preparation of a hybrid electrode system via polydiacetylene (PDA) cloaking on the surface of aligned multiwall carbon nanotubes (MWCNTs) through self-assembly based in situ photopolymerization. This strategy eliminates the need for initiators and binders that hinder electrochemical performance in conventional conducting polymer based composite electrodes. As noncovalent PDA cloaking did not alter the chemical structure of MWCNTs, high inherent conductivity from sp(2) hybridized carbon was preserved. The resulting hybrid microfiber (MWCNT@PDA) exhibited a significant increase in specific capacitance (1111 F g(-1)) when compared to bare MWCNTs (500 F g(-1)) and PDA (666.7 F g(-1)) in a voltage window of 0-1.2 V at a current density of 3 A g(-1) in 0.5 M K2SO4 electrolyte. The specific capacitance was retained (ca. 95%) after 7000 charge/discharge cycles. The present results suggest that aligned MWCNTs cloaked with conjugated polymers could meet the demands for future flexible electronics.

  12. Lightweight, flexible, high-performance carbon nanotube cables made by scalable flow coating

    DOE PAGES

    Mirri, Francesca; Orloff, Nathan D.; Forser, Aaron M.; ...

    2016-01-21

    Coaxial cables for data transmission are ubiquitous in telecommunications, aerospace, automotive, and robotics industries. Yet, the metals used to make commercial cables are unsuitably heavy and stiff. These undesirable traits are particularly problematic in aerospace applications, where weight is at a premium and flexibility is necessary to conform with the distributed layout of electronic components in satellites and aircraft. The cable outer conductor (OC) is usually the heaviest component of modern data cables; therefore, exchanging the conventional metallic OC for lower weight materials with comparable transmission characteristics is highly desirable. Carbon nanotubes (CNTs) have recently been proposed to replace themore » metal components in coaxial cables; however, signal attenuation was too high in prototypes produced so far. Here, we fabricate the OC of coaxial data cables by directly coating a solution of CNTs in chlorosulfonic acid (CSA) onto the cable inner dielectric. This coating has an electrical conductivity that is approximately 2 orders of magnitude greater than the best CNT OC reported in the literature to date. In conclusion, this high conductivity makes CNT coaxial cables an attractive alternative to commercial cables with a metal (tin-coated copper) OC, providing comparable cable attenuation and mechanical durability with a 97% lower component mass.« less

  13. Lightweight, flexible, high-performance carbon nanotube cables made by scalable flow coating

    SciTech Connect

    Mirri, Francesca; Orloff, Nathan D.; Forser, Aaron M.; Ashkar, Rana; Headrick, Robert J.; Bengio, E. Amram; Long, Christian J.; Choi, April; Luo, Yimin; Hight Walker, Angela R.; Butler, Paul; Migler, Kalman B.; Pasquali, Matteo

    2016-01-21

    Coaxial cables for data transmission are ubiquitous in telecommunications, aerospace, automotive, and robotics industries. Yet, the metals used to make commercial cables are unsuitably heavy and stiff. These undesirable traits are particularly problematic in aerospace applications, where weight is at a premium and flexibility is necessary to conform with the distributed layout of electronic components in satellites and aircraft. The cable outer conductor (OC) is usually the heaviest component of modern data cables; therefore, exchanging the conventional metallic OC for lower weight materials with comparable transmission characteristics is highly desirable. Carbon nanotubes (CNTs) have recently been proposed to replace the metal components in coaxial cables; however, signal attenuation was too high in prototypes produced so far. Here, we fabricate the OC of coaxial data cables by directly coating a solution of CNTs in chlorosulfonic acid (CSA) onto the cable inner dielectric. This coating has an electrical conductivity that is approximately 2 orders of magnitude greater than the best CNT OC reported in the literature to date. In conclusion, this high conductivity makes CNT coaxial cables an attractive alternative to commercial cables with a metal (tin-coated copper) OC, providing comparable cable attenuation and mechanical durability with a 97% lower component mass.

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

    SciTech Connect

    Mayhew, Eric; Prakash, Vikas

    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.

  15. Hierarchical, porous CuS microspheres integrated with carbon nanotubes for high-performance supercapacitors

    PubMed Central

    Lu, Yang; Liu, Xianming; Wang, Weixiao; Cheng, Jinbing; Yan, Hailong; Tang, Chengchun; Kim, Jang-Kyo; Luo, Yongsong

    2015-01-01

    Carbon nanotubes (CNTs) incorporated porous 3-dimensional (3D) CuS microspheres have been successfully synthesized via a simple refluxing method assisted by PVP. The composites are composed of flower-shaped CuS secondary microspheres, which in turn are assembled with primary nanosheets of 15–30 nm in thickness and fully integrated with CNT. The composites possess a large specific surface area of 189.6 m2 g−1 and a high conductivity of 0.471 S cm−1. As electrode materials for supercapacitors, the nanocomposites show excellent cyclability and rate capability and deliver an average reversible capacitance as high as 1960 F g−1 at a current density of 10 mA cm−2 over 10000 cycles. The high electrochemical performance can be attributed to the synergistic effect of CNTs and the unique microstructure of CuS. The CNTs serve as not only a conductive agent to accelerate the transfer of electrons in the composites, but also as a buffer matrix to restrain the volume change and stabilize the electrode structure during the charge/discharge process. The porous structure of CuS also helps to stabilize the electrode structure and facilitates the transport for electrons. PMID:26568518

  16. High performance dendrimer functionalized single-walled carbon nanotubes field effect transistor biosensor for protein detection

    NASA Astrophysics Data System (ADS)

    Rajesh, Sharma, Vikash; Puri, Nitin K.; Mulchandani, Ashok; Kotnala, Ravinder K.

    2016-12-01

    We report a single-walled carbon nanotube (SWNT) field-effect transistor (FET) functionalized with Polyamidoamine (PAMAM) dendrimer with 128 carboxyl groups as anchors for site specific biomolecular immobilization of protein antibody for C-reactive protein (CRP) detection. The FET device was characterized by scanning electron microscopy and current-gate voltage (I-Vg) characteristic studies. A concentration-dependent decrease in the source-drain current was observed in the regime of clinical significance, with a detection limit of ˜85 pM and a high sensitivity of 20% change in current (ΔI/I) per decade CRP concentration, showing SWNT being locally gated by the binding of CRP to antibody (anti-CRP) on the FET device. The low value of the dissociation constant (Kd = 0.31 ± 0.13 μg ml-1) indicated a high affinity of the device towards CRP analyte arising due to high anti-CRP loading with a better probe orientation on the 3-dimensional PAMAM structure.

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

    PubMed

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

    2016-08-10

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

  18. High-performance field emission of carbon nanotube paste emitters fabricated using graphite nanopowder filler

    NASA Astrophysics Data System (ADS)

    Sun, Yuning; Yun, Ki Nam; Leti, Guillaume; Lee, Sang Heon; Song, Yoon-Ho; Lee, Cheol Jin

    2017-02-01

    Carbon nanotube (CNT) paste emitters were fabricated using graphite nanopowder filler. The CNT paste emitters consist of CNTs as the emitting material, graphite nanopowder as the filler and a graphite rod as the cathode. Rather than metal or inorganic materials, graphite nanopowder was adapted as a filler material to make the CNT paste emitters. After fabricating the emitters, sandpaper treatment was applied to increase the density of emission sites. The CNT paste emitters showed a high field emission performance, for example a high emission current of 8.5 mA from a cylindrical emitter with a diameter of 0.7 mm (corresponding to a current density of 2.2 A cm-2) and an extremely stable emission current at 1 mA (260 mA cm-2 for 20 h). Interestingly, after a number of electrical arcing events, the emitters still showed a high emission current of 5-8 mA (higher than 1 A cm-2). In addition to the sound electrical and thermal properties of the graphite filler, effective mechanical adhesion of the CNTs onto the graphite cathode induced by the use of the graphite nanopowder filler contributed the excellent field emission properties of the CNT paste emitters.

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

    NASA Astrophysics Data System (ADS)

    Mayhew, Eric; Prakash, Vikas

    2014-05-01

    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.

  20. Lightweight, Flexible, High-Performance Carbon Nanotube Cables Made by Scalable Flow Coating.

    PubMed

    Mirri, Francesca; Orloff, Nathan D; Forster, Aaron M; Ashkar, Rana; Headrick, Robert J; Bengio, E Amram; Long, Christian J; Choi, April; Luo, Yimin; Walker, Angela R Hight; Butler, Paul; Migler, Kalman B; Pasquali, Matteo

    2016-02-01

    Coaxial cables for data transmission are ubiquitous in telecommunications, aerospace, automotive, and robotics industries. Yet, the metals used to make commercial cables are unsuitably heavy and stiff. These undesirable traits are particularly problematic in aerospace applications, where weight is at a premium and flexibility is necessary to conform with the distributed layout of electronic components in satellites and aircraft. The cable outer conductor (OC) is usually the heaviest component of modern data cables; therefore, exchanging the conventional metallic OC for lower weight materials with comparable transmission characteristics is highly desirable. Carbon nanotubes (CNTs) have recently been proposed to replace the metal components in coaxial cables; however, signal attenuation was too high in prototypes produced so far. Here, we fabricate the OC of coaxial data cables by directly coating a solution of CNTs in chlorosulfonic acid (CSA) onto the cable inner dielectric. This coating has an electrical conductivity that is approximately 2 orders of magnitude greater than the best CNT OC reported in the literature to date. This high conductivity makes CNT coaxial cables an attractive alternative to commercial cables with a metal (tin-coated copper) OC, providing comparable cable attenuation and mechanical durability with a 97% lower component mass.

  1. Pt nanocatalysts on a polyindole-functionalized carbon nanotube composite with high performance for methanol electrooxidation

    NASA Astrophysics Data System (ADS)

    Wang, Rui-Xiang; Fan, You-Jun; Wang, Li; Wu, Li-Na; Sun, Sheng-Nan; Sun, Shi-Gang

    2015-08-01

    Herein, we report a novel electrocatalyst consisting of Pt nanoparticles supported on a polyindole (PIn)-functionalized multi-walled carbon nanotube (MWCNT) composite (Pt/PIn-MWCNT) for use in the methanol oxidation reaction (MOR). The PIn-MWCNT support is synthesized via in situ chemical polymerization of indole on the MWCNT surface. The transmission electron microscopy (TEM) images indicated that the Pt nanoparticles were approximately 3.0 nm in size and were uniformly deposited on the surface of PIn-MWCNTs with no aggregation into larger clusters. X-ray photoelectron spectroscopy (XPS) measurements confirm the strong electron interaction between the Pt nanoparticles and the PIn-MWCNT support as well as the formation of the Pt-N bond. The electrochemical tests demonstrate that the Pt/PIn-MWCNT composite exhibits much higher electrocatalytic activity, durability and CO tolerance than the Pt/MWCNT and commercial Pt/C catalysts toward MOR. The results indicate that the as-prepared Pt/PIn-MWCNTs are promising for use as an anode electrocatalyst in direct methanol fuel cells (DMFCs).

  2. High Performance Carbon Nanotube Yarn Supercapacitors with a Surface-Oxidized Copper Current Collector.

    PubMed

    Zhang, Daohong; Wu, Yunlong; Li, Ting; Huang, Yin; Zhang, Aiqing; Miao, Menghe

    2015-11-25

    Threadlike linear supercapacitors have demonstrated high potential for constructing fabrics to power electronic textiles (eTextiles). To improve the cyclic electrochemical performance and to produce power fabrics large enough for practical applications, a current collector has been introduced into the linear supercapcitors to transport charges produced by active materials along the length of the supercapacitor with high efficiency. Here, we first screened six candidate metal filaments (Pt, Au, Ag, AuAg, PtCu, and Cu) as current collectors for carbon nanotube (CNT) yarn-based linear supercapacitors. Although all of the metal filaments significantly improved the electrochemical performance of the linear supercapacitor, two supercapacitors constructed from Cu and PtCu filaments, respectively, demonstrate far better electrochemical performance than the other four supercapacitors. Further investigation shows that the surfaces of the two Cu-containing filaments are oxidized by the surrounding polymer electrolyte in the electrode. While the unoxidized core of the Cu-containing filaments remains highly conductive and functions as a current collector, the resulting CuO on the surface is an electrochemically active material. The linear supercapacitor architecture incorporating dual active materials CNT + Cu extends the potential window from 1.0 to 1.4 V, leading to significant improvement to the energy density and power density.

  3. High-performance field emission of carbon nanotube paste emitters fabricated using graphite nanopowder filler.

    PubMed

    Sun, Yuning; Yun, Ki Nam; Leti, Guillaume; Lee, Sang Heon; Song, Yoon-Ho; Lee, Cheol Jin

    2017-02-10

    Carbon nanotube (CNT) paste emitters were fabricated using graphite nanopowder filler. The CNT paste emitters consist of CNTs as the emitting material, graphite nanopowder as the filler and a graphite rod as the cathode. Rather than metal or inorganic materials, graphite nanopowder was adapted as a filler material to make the CNT paste emitters. After fabricating the emitters, sandpaper treatment was applied to increase the density of emission sites. The CNT paste emitters showed a high field emission performance, for example a high emission current of 8.5 mA from a cylindrical emitter with a diameter of 0.7 mm (corresponding to a current density of 2.2 A cm(-2)) and an extremely stable emission current at 1 mA (260 mA cm(-2) for 20 h). Interestingly, after a number of electrical arcing events, the emitters still showed a high emission current of 5-8 mA (higher than 1 A cm(-2)). In addition to the sound electrical and thermal properties of the graphite filler, effective mechanical adhesion of the CNTs onto the graphite cathode induced by the use of the graphite nanopowder filler contributed the excellent field emission properties of the CNT paste emitters.

  4. Highly Conductive Aromatic Functionalized Multi-Walled Carbon Nanotube for Inkjet Printable High Performance Supercapacitor Electrodes

    PubMed Central

    Attri, Pankaj

    2015-01-01

    We report the functionalization of multiwalled carbon nanotubes (MWCNT) via the 1,3-dipolar [3+2] cycloaddition of aromatic azides, which resulted in a detangled CNT as shown by transmission electron microscopy (TEM). Carboxylic moieties (-COOH) on aromatic azide result in highly stable aqueous dispersion (max. conc. ~ 10 mg/mL H2O), making the suitable for inkjet printing. Printed patterns on polyethylene terephthalate (PET) flexible substrate exhibit low sheet resistivity ~65 Ω. cm, which is attributed to enhanced conductivity. Fabricated Supercapacitors (SC) assembled using these printed substrates exhibit good electrochemical performance in organic as well as aqueous electrolytes. High energy and power density (57.8 Wh/kg and 0.85 kW/kg) in 1M H2SO4 aqueous electrolyte demonstrate the excellent performance of the proposed supercapacitor. Capacitive retention varies from ~85–94% with columbic efficiency ~95% after 1000 charge/discharge cycles in different electrolytes, demonstrating the excellent potential of the device for futuristic power applications. PMID:26153688

  5. Toward high performance thermoset/carbon nanotube sheet nanocomposites via resistive heating assisted infiltration and cure.

    PubMed

    Kim, Jae-Woo; Sauti, Godfrey; Siochi, Emilie J; Smith, Joseph G; Wincheski, Russell A; Cano, Roberto J; Connell, John W; Wise, Kristopher E

    2014-11-12

    Thermoset/carbon nanotube (CNT) sheet nanocomposites were successfully fabricated by resistive heating assisted infiltration and cure (RHAIC) of the polymer matrix resin. Resistive heating takes advantage of the electrical and thermal conductivity of CNTs to rapidly and uniformly introduce heat into the CNT sheet. Heating the CNT sheet reduces the viscosity of the polymer resin due to localized temperature rise in close proximity to the resin, which enhances resin flow, penetration, and wetting of the CNT reinforcement. Once the resin infusion process is complete, the applied power is increased to raise the temperature of the CNT sheet, which rapidly cures the polymer matrix. Tensile tests were used to evaluate the mechanical properties of the processed thermoset/CNT sheet nanocomposites. The improved wetting and adhesion of the polymer resin to the CNT reinforcement yield significant improvement of thermoset/CNT nanocomposite mechanical properties. The highest specific tensile strength of bismaleimide(BMI)/CNT sheet nanocomposites was obtained to date was 684 MPa/(g/cm(3)), using 4 V (2 A) for resin infiltration, followed by precure at 10 V (6 A) for 10 min and post curing at 240 °C for 6 h in an oven. The highest specific Young's modulus of BMI/CNT sheet nanocomposite was 71 GPa/(g/cm(3)) using resistive heating infiltration at 8.3 V (4.7 A) for 3 min followed by resistive heating cure at 12.5 V (7 A) for 30 min. In both cases, the CNT sheets were stretched and held in tension to prevent relaxation of the aligned CNTs during the course of RHAIC.

  6. High-performance and compact-designed flexible thermoelectric modules enabled by a reticulate carbon nanotube architecture

    NASA Astrophysics Data System (ADS)

    Zhou, Wenbin; Fan, Qingxia; Zhang, Qiang; Cai, Le; Li, Kewei; Gu, Xiaogang; Yang, Feng; Zhang, Nan; Wang, Yanchun; Liu, Huaping; Zhou, Weiya; Xie, Sishen

    2017-03-01

    It is a great challenge to substantially improve the practical performance of flexible thermoelectric modules due to the absence of air-stable n-type thermoelectric materials with high-power factor. Here an excellent flexible n-type thermoelectric film is developed, which can be conveniently and rapidly prepared based on the as-grown carbon nanotube continuous networks with high conductivity. The optimum n-type film exhibits ultrahigh power factor of ~1,500 μW m-1 K-2 and outstanding stability in air without encapsulation. Inspired by the findings, we design and successfully fabricate the compact-configuration flexible TE modules, which own great advantages compared with the conventional π-type configuration modules and well integrate the superior thermoelectric properties of p-type and n-type carbon nanotube films resulting in a markedly high performance. Moreover, the research results are highly scalable and also open opportunities for the large-scale production of flexible thermoelectric modules.

  7. High-performance and compact-designed flexible thermoelectric modules enabled by a reticulate carbon nanotube architecture.

    PubMed

    Zhou, Wenbin; Fan, Qingxia; Zhang, Qiang; Cai, Le; Li, Kewei; Gu, Xiaogang; Yang, Feng; Zhang, Nan; Wang, Yanchun; Liu, Huaping; Zhou, Weiya; Xie, Sishen

    2017-03-24

    It is a great challenge to substantially improve the practical performance of flexible thermoelectric modules due to the absence of air-stable n-type thermoelectric materials with high-power factor. Here an excellent flexible n-type thermoelectric film is developed, which can be conveniently and rapidly prepared based on the as-grown carbon nanotube continuous networks with high conductivity. The optimum n-type film exhibits ultrahigh power factor of ∼1,500 μW m(-1) K(-2) and outstanding stability in air without encapsulation. Inspired by the findings, we design and successfully fabricate the compact-configuration flexible TE modules, which own great advantages compared with the conventional π-type configuration modules and well integrate the superior thermoelectric properties of p-type and n-type carbon nanotube films resulting in a markedly high performance. Moreover, the research results are highly scalable and also open opportunities for the large-scale production of flexible thermoelectric modules.

  8. High-performance multi-functional reverse osmosis membranes obtained by carbon nanotube·polyamide nanocomposite

    PubMed Central

    Inukai, Shigeki; Cruz-Silva, Rodolfo; Ortiz-Medina, Josue; Morelos-Gomez, Aaron; Takeuchi, Kenji; Hayashi, Takuya; Tanioka, Akihiko; Araki, Takumi; Tejima, Syogo; Noguchi, Toru; Terrones, Mauricio; Endo, Morinobu

    2015-01-01

    Clean water obtained by desalinating sea water or by purifying wastewater, constitutes a major technological objective in the so-called water century. In this work, a high-performance reverse osmosis (RO) composite thin membrane using multi-walled carbon nanotubes (MWCNT) and aromatic polyamide (PA), was successfully prepared by interfacial polymerization. The effect of MWCNT on the chlorine resistance, antifouling and desalination performances of the nanocomposite membranes were studied. We found that a suitable amount of MWCNT in PA, 15.5 wt.%, not only improves the membrane performance in terms of flow and antifouling, but also inhibits the chlorine degradation on these membranes. Therefore, the present results clearly establish a solid foundation towards more efficient large-scale water desalination and other water treatment processes. PMID:26333385

  9. High-performance multi-functional reverse osmosis membranes obtained by carbon nanotube·polyamide nanocomposite.

    PubMed

    Inukai, Shigeki; Cruz-Silva, Rodolfo; Ortiz-Medina, Josue; Morelos-Gomez, Aaron; Takeuchi, Kenji; Hayashi, Takuya; Tanioka, Akihiko; Araki, Takumi; Tejima, Syogo; Noguchi, Toru; Terrones, Mauricio; Endo, Morinobu

    2015-09-03

    Clean water obtained by desalinating sea water or by purifying wastewater, constitutes a major technological objective in the so-called water century. In this work, a high-performance reverse osmosis (RO) composite thin membrane using multi-walled carbon nanotubes (MWCNT) and aromatic polyamide (PA), was successfully prepared by interfacial polymerization. The effect of MWCNT on the chlorine resistance, antifouling and desalination performances of the nanocomposite membranes were studied. We found that a suitable amount of MWCNT in PA, 15.5 wt.%, not only improves the membrane performance in terms of flow and antifouling, but also inhibits the chlorine degradation on these membranes. Therefore, the present results clearly establish a solid foundation towards more efficient large-scale water desalination and other water treatment processes.

  10. High-performance multi-functional reverse osmosis membranes obtained by carbon nanotube·polyamide nanocomposite

    NASA Astrophysics Data System (ADS)

    Inukai, Shigeki; Cruz-Silva, Rodolfo; Ortiz-Medina, Josue; Morelos-Gomez, Aaron; Takeuchi, Kenji; Hayashi, Takuya; Tanioka, Akihiko; Araki, Takumi; Tejima, Syogo; Noguchi, Toru; Terrones, Mauricio; Endo, Morinobu

    2015-09-01

    Clean water obtained by desalinating sea water or by purifying wastewater, constitutes a major technological objective in the so-called water century. In this work, a high-performance reverse osmosis (RO) composite thin membrane using multi-walled carbon nanotubes (MWCNT) and aromatic polyamide (PA), was successfully prepared by interfacial polymerization. The effect of MWCNT on the chlorine resistance, antifouling and desalination performances of the nanocomposite membranes were studied. We found that a suitable amount of MWCNT in PA, 15.5 wt.%, not only improves the membrane performance in terms of flow and antifouling, but also inhibits the chlorine degradation on these membranes. Therefore, the present results clearly establish a solid foundation towards more efficient large-scale water desalination and other water treatment processes.

  11. The possibility of high-performance n-type carbon nanotube devices by fullerene functionalization: A first-principles study

    NASA Astrophysics Data System (ADS)

    Kim, Yong-Hoon; in Lee, Ga; Kang, Jeungku

    2010-03-01

    The successive appearance of low-dimensional carbon nanomaterials, such as zero-dimensional [60]fullerene (C60), one-dimensional carbon nanotube (CNT), and two-dimensional graphene, has been an inexhaustible source for the study of novel scientific principles and the search of advanced technological applications. Recently, about a decade after the discovery of the first C60-CNT hybrid form, carbon nanopeapod, a new hybrid C60-CNT nanostructure termed as ``carbon nanobud'' has been synthesized [1]. Extending our earlier study of polymerized C60 nanowires [2], we here apply a first-principles computational approach [3] to consider the C60 functionalization of CNTs as a scheme to engineer the CNT-metal contacts to produce reliable high-performance n-type CNT devices. References: [1] A.G. Nasibulin, et al., Nat. Nanotechnol. 2, 156 (2007). [2] G. I. Lee, J. K. Kang, and Y.-H. Kim, J. Phys. Chem. C 112, 7029 (2008). [3] Y.-H. Kim et al., Phys. Rev. Lett. 94, 156801 (2005).

  12. Mixtures of oppositely charged polypeptides as high-performance dispersing agents for single-wall carbon nanotubes.

    PubMed

    Lee, Gordon K-C; Sach, Clare; Green, Malcolm L H; Wong, Luet-Lok; Salzmann, Christoph G

    2010-10-07

    A new and simple strategy for the dispersion of single-wall carbon nanotubes in aqueous media is presented which does not rely on hydrophobic interactions between the polypeptidic dispersing agent and the nanotubes, and allows the surface charge of the resulting conjugate materials to be controlled.

  13. High-performance Supercapacitors Based on Electrochemical-induced Vertical-aligned Carbon Nanotubes and Polyaniline Nanocomposite Electrodes

    NASA Astrophysics Data System (ADS)

    Wu, Guan; Tan, Pengfeng; Wang, Dongxing; Li, Zhe; Peng, Lu; Hu, Ying; Wang, Caifeng; Zhu, Wei; Chen, Su; Chen, Wei

    2017-03-01

    Supercapacitors, which store electrical energy through reversible ion on the surface of conductive electrodes have gained enormous attention for variously portable energy storage devices. Since the capacitive performance is mainly determined by the structural and electrochemical properties of electrodes, the electrodes become more crucial to higher performance. However, due to the disordered microstructure and low electrochemical activity of electrode for ion tortuous migration and accumulation, the supercapacitors present relatively low capacitance and energy density. Here we report a high-performance supercapacitor based on polyaniline/vertical-aligned carbon nanotubes (PANI/VA-CNTs) nanocomposite electrodes where the vertical-aligned-structure is formed by the electrochemical-induction (0.75 V). The supercapacitor displays large specific capacitance of 403.3 F g‑1, which is 6 times higher than disordered CNTs in HClO4 electrolyte. Additionally, the supercapacitor can also present high specific capacitance (314.6 F g‑1), excellent cycling stability (90.2% retention after 3000 cycles at 4 A g‑1) and high energy density (98.1 Wh kg‑1) in EMIBF4 organic electrolyte. The key to high-performance lies in the vertical-aligned-structure providing direct path channel for ion faster diffusion and high electrochemical capacitance of polyaniline for ion more accommodation.

  14. High-performance Supercapacitors Based on Electrochemical-induced Vertical-aligned Carbon Nanotubes and Polyaniline Nanocomposite Electrodes

    PubMed Central

    Wu, Guan; Tan, Pengfeng; Wang, Dongxing; Li, Zhe; Peng, Lu; Hu, Ying; Wang, Caifeng; Zhu, Wei; Chen, Su; Chen, Wei

    2017-01-01

    Supercapacitors, which store electrical energy through reversible ion on the surface of conductive electrodes have gained enormous attention for variously portable energy storage devices. Since the capacitive performance is mainly determined by the structural and electrochemical properties of electrodes, the electrodes become more crucial to higher performance. However, due to the disordered microstructure and low electrochemical activity of electrode for ion tortuous migration and accumulation, the supercapacitors present relatively low capacitance and energy density. Here we report a high-performance supercapacitor based on polyaniline/vertical-aligned carbon nanotubes (PANI/VA-CNTs) nanocomposite electrodes where the vertical-aligned-structure is formed by the electrochemical-induction (0.75 V). The supercapacitor displays large specific capacitance of 403.3 F g−1, which is 6 times higher than disordered CNTs in HClO4 electrolyte. Additionally, the supercapacitor can also present high specific capacitance (314.6 F g−1), excellent cycling stability (90.2% retention after 3000 cycles at 4 A g−1) and high energy density (98.1 Wh kg−1) in EMIBF4 organic electrolyte. The key to high-performance lies in the vertical-aligned-structure providing direct path channel for ion faster diffusion and high electrochemical capacitance of polyaniline for ion more accommodation. PMID:28272474

  15. High-Performance Complementary Transistors and Medium-Scale Integrated Circuits Based on Carbon Nanotube Thin Films.

    PubMed

    Yang, Yingjun; Ding, Li; Han, Jie; Zhang, Zhiyong; Peng, Lian-Mao

    2017-03-29

    Solution-derived carbon nanotube (CNT) network films with high semiconducting purity are suitable materials for the wafer-scale fabrication of field-effect transistors (FETs) and integrated circuits (ICs). However, it is challenging to realize high-performance complementary metal-oxide semiconductor (CMOS) FETs with high yield and stability on such CNT network films, and this difficulty hinders the development of CNT-film-based ICs. In this work, we developed a doping-free process for the fabrication of CMOS FETs based on solution-processed CNT network films, in which the polarity of the FETs was controlled using Sc or Pd as the source/drain contacts to selectively inject carriers into the channels. The fabricated top-gated CMOS FETs showed high symmetry between the characteristics of n- and p-type devices and exhibited high-performance uniformity and excellent scalability down to a gate length of 1 μm. Many common types of CMOS ICs, including typical logic gates, sequential circuits, and arithmetic units, were constructed based on CNT films, and the fabricated ICs exhibited rail-to-rail outputs because of the high noise margin of CMOS circuits. In particular, 4-bit full adders consisting of 132 CMOS FETs were realized with 100% yield, thereby demonstrating that this CMOS technology shows the potential to advance the development of medium-scale CNT-network-film-based ICs.

  16. Nanostructured Black Phosphorus/Ketjenblack-Multiwalled Carbon Nanotubes Composite as High Performance Anode Material for Sodium-Ion Batteries.

    PubMed

    Xu, Gui-Liang; Chen, Zonghai; Zhong, Gui-Ming; Liu, Yuzi; Yang, Yong; Ma, Tianyuan; Ren, Yang; Zuo, Xiaobing; Wu, Xue-Hang; Zhang, Xiaoyi; Amine, Khalil

    2016-06-08

    Sodium-ion batteries are promising alternatives to lithium-ion batteries for large-scale applications. However, the low capacity and poor rate capability of existing anodes for sodium-ion batteries are bottlenecks for future developments. Here, we report a high performance nanostructured anode material for sodium-ion batteries that is fabricated by high energy ball milling to form black phosphorus/Ketjenblack-multiwalled carbon nanotubes (BPC) composite. With this strategy, the BPC composite with a high phosphorus content (70 wt %) could deliver a very high initial Coulombic efficiency (>90%) and high specific capacity with excellent cyclability at high rate of charge/discharge (∼1700 mAh g(-1) after 100 cycles at 1.3 A g(-1) based on the mass of P). In situ electrochemical impedance spectroscopy, synchrotron high energy X-ray diffraction, ex situ small/wide-angle X-ray scattering, high resolution transmission electronic microscopy, and nuclear magnetic resonance were further used to unravel its superior sodium storage performance. The scientific findings gained in this work are expected to serve as a guide for future design on high performance anode material for sodium-ion batteries.

  17. High performance field emission and Nottingham effect observed from carbon nanotube yarn

    NASA Astrophysics Data System (ADS)

    Choi, Young Chul; Kang, Jun-Tae; Park, Sora; Go, Eunsol; Jeon, Hyojin; Kim, Jae-Woo; Jeong, Jin-Woo; Park, Kyung-Ho; Song, Yoon-Ho

    2017-02-01

    Vertically aligned CNTs were synthesized on a four inch wafer, followed by the preparation of a CNT yarn. The yarn emitter was found to have an extremely high field enhancement factor, which was confirmed to have originated from multi-stage effect. In addition to superb field emission characteristics, the energy exchange during field emission, called Nottingham effect, was observed from the CNT yarn emitter. A CNT yarn was attached to the thermistor whose resistance depends on temperature. Then, the change of resistance was monitored during the field emission, which enabled us to calculate the energy exchange. It was found that the observed heating originated from both Nottingham and Joule heating. Nottingham heating was dominant at low current region while Joule heating became larger contribution at high current region. Very large Nottingham region of up to 33.35 mA was obtained, which is due presumably to the high performance field emission characteristics of a CNT yarn. This is believed to be an important observation for developing reliable field emission devices with suppressed Joule heating effect.

  18. High performance nanocomposite thin film transistors with bilayer carbon nanotube-polythiophene active channel by ink-jet printing

    NASA Astrophysics Data System (ADS)

    Hsieh, Gen-Wen; Li, Flora M.; Beecher, Paul; Nathan, Arokia; Wu, Yiliang; Ong, Beng S.; Milne, William I.

    2009-12-01

    Nanocomposite thin film transistors (TFTs) based on nonpercolating networks of single-walled carbon nanotubes (CNTs) and polythiophene semiconductor [poly[5,5'-bis(3-dodecyl-2-thienyl)-2,2'-bithiophene] (PQT-12)] thin film hosts are demonstrated by ink-jet printing. A systematic study on the effect of CNT loading on the transistor performance and channel morphology is conducted. With an appropriate loading of CNTs into the active channel, ink-jet printed composite transistors show an effective hole mobility of 0.23 cm2 V-1 s-1, which is an enhancement of more than a factor of 7 over ink-jet printed pristine PQT-12 TFTs. In addition, these devices display reasonable on/off current ratio of 105-106, low off currents of the order of 10 pA, and a sharp subthreshold slope (<0.8 V dec-1). The work presented here furthers our understanding of the interaction between polythiophene polymers and nonpercolating CNTs, where the CNT density in the bilayer structure substantially influences the morphology and transistor performance of polythiophene. Therefore, optimized loading of ink-jet printed CNTs is crucial to achieve device performance enhancement. High performance ink-jet printed nanocomposite TFTs can present a promising alternative to organic TFTs in printed electronic applications, including displays, sensors, radio-frequency identification (RFID) tags, and disposable electronics.

  19. Flexible Transparent Films Based on Nanocomposite Networks of Polyaniline and Carbon Nanotubes for High-Performance Gas Sensing.

    PubMed

    Wan, Pengbo; Wen, Xuemei; Sun, Chaozheng; Chandran, Bevita K; Zhang, Han; Sun, Xiaoming; Chen, Xiaodong

    2015-10-28

    A flexible, transparent, chemical gas sensor is assembled from a transparent conducting film of carbon nanotube (CNT) networks that are coated with hierarchically nanostructured polyaniline (PANI) nanorods. The nanocomposite film is synthesized by in-situ, chemical oxidative polymerization of aniline in a functional multiwalled CNT (FMWCNT) suspension and is simultaneously deposited onto a flexible polyethylene terephthalate (PET) substrate. An as-prepared flexible transparent chemical gas sensor exhibits excellent transparency of 85.0% at 550 nm using the PANI/FMWCNT nanocomposite film prepared over a reaction time of 8 h. The sensor also shows good flexibility, without any obvious decrease in performance after 500 bending/extending cycles, demonstrating high-performance, portable gas sensing at room temperature. This superior performance could be attributed to the improved electron transport and collection due to the CNTs, resulting in reliable and efficient sensing, as well as the high surface-to-volume ratio of the hierarchically nanostructured composites. The excellent transparency, improved sensing performance, and superior flexibility of the device, may enable the integration of this simple, low-cost, gas sensor into handheld flexible transparent electronic circuitry and optoelectronic devices.

  20. Vacuum filtration based formation of liquid crystal films of semiconducting carbon nanotubes and high performance transistor devices

    NASA Astrophysics Data System (ADS)

    King, Benjamin; Panchapakesan, Balaji

    2014-05-01

    In this paper, we report ultra-thin liquid crystal films of semiconducting carbon nanotubes using a simple vacuum filtration process. Vacuum filtration of nanotubes in aqueous surfactant solution formed nematic domains on the filter membrane surface and exhibited local ordering. A 2D fast Fourier transform was used to calculate the order parameters from scanning electron microscopy images. The order parameter was observed to be sensitive to the filtration time demonstrating different regions of transformation namely nucleation of nematic domains, nanotube accumulation and large domain growth.Transmittance versus sheet resistance measurements of such films resulted in optical to dc conductivity of σ opt/σ dc = 9.01 indicative of purely semiconducting nanotube liquid crystal network.Thin films of nanotube liquid crystals with order parameters ranging from S = 0.1-0.5 were patterned into conducting channels of transistor devices which showed high I on/I off ratios from 10-19 800 and electron mobility values μ e = 0.3-78.8 cm2 (V-s)-1, hole mobility values μ h = 0.4-287 cm2 (V-s)-1. High I on/I off ratios were observed at low order parameters and film mass. A Schottky barrier transistor model is consistent with the observed transistor characteristics. Electron and hole mobilities were seen to increase with order parameters and carbon nanotube mass fractions. A fundamental tradeoff between decreasing on/off ratio and increasing mobility with increasing nanotube film mass and order parameter is therefore concluded. Increase in order parameters of nanotubes liquid crystals improved the electronic transport properties as witnessed by the increase in σ dc/σ opt values on macroscopic films and high mobilities in microscopic transistors. Liquid crystal networks of semiconducting nanotubes as demonstrated here are simple to fabricate, transparent, scalable and could find wide ranging device applications.

  1. Four-layer tin-carbon nanotube yolk-shell materials for high-performance lithium-ion batteries.

    PubMed

    Chen, Peng; Wu, Fengdan; Wang, Yong

    2014-05-01

    All high-capacity anodes for lithium-ion (Li-ion) batteries, such as those based on tin (Sn) and silicon (Si), suffer from large volume changes during cycling with lithium ions, and their high capacities can be only achieved in the first few cycles. We design and synthesize a unique four-layer yolk-shell tin-carbon (Sn-C) nanotube array to address this problem. The shape and size of the exterior Sn nanotube@carbon core-shell layer, the encapsulated interior Sn nanowire@carbon nanotube core-shell layer, and the filling level of each layer can be all controlled by adjusting the experimental conditions. Such a nanostructure has not been reported for any metal or metal oxide-based material. Owing to the special design of the electrode structure, the four-layer hierarchical structure demonstrates excellent Li-ion storage properties in terms of high capacity, long cycle life, and high rate performance.

  2. Fabrication of copper nanoparticles decorated multiwalled carbon nanotubes as a high performance electrochemical sensor for the detection of neotame.

    PubMed

    Bathinapatla, Ayyappa; Kanchi, Suvardhan; Singh, Parvesh; Sabela, Myalowenkosi I; Bisetty, Krishna

    2015-05-15

    A highly sensitive and novel electrochemical sensor for the detection of neotame using differential pulse voltammetry with a modified glassy carbon electrode is presented. The method was further customized by the fabrication of the electrode surface with copper nanoparticles-ammonium piperidine dithiocarbamate-mutiwalled carbon nanotubes assimilated with β-cyclodextrin. The multiwalled carbon nanotubes assimilated with β-cyclodextrin/glassy carbon electrode exhibited catalytic activity towards the oxidation of neotame at a potential of 1.3 V at pH 3.0. The transmission electron microscopy, thermogravimetric analysis, frontier transform infrared spectroscopy and cyclic voltammetry were employed to characterize the electrochemical sensor. The sensitivity and detection limits of the electrode increased two-fold in contrast to the β-CD-MWCNTs/GCE sensor. The developed method was successfully applied for the determination of neotame in food samples, with results similar to those achieved by our modified capillary electrophoresis method with a 96% confidence level.

  3. Manufacturing of high performance polymer nanocomposites containing carbon nanotubes and carbon nanofibers using ultrasound assisted extrusion process

    NASA Astrophysics Data System (ADS)

    Kumar, Rishi

    The major objective of this study was to investigate the effect of ultrasonic treatment on the state of dispersion and properties of carbon nanotubes (CNTs) and carbon nanofibers (CNFs) in polymer matrices. In order to achieve this objective, an ultrasonic single screw extruder operating at a frequency of 20 kHz and an amplitude of upto 10 microm and an ultrasonic twin screw extruder operating at a frequency of 40 kHz and an amplitude of upto 6.0 microm, were used to process highly viscous materials and disperse these nanofillers homogeneously in a polymer matrix at residence times of order of seconds. High temperature thermoplastic resins including polyetherimide (PEI), liquid crystalline polymer (LCP) and polyetheretherketone (PEEK) were used. Multiwalled carbon nanotubes (MWNTs) and CNFs were used as reinforcing fillers. The effect of nanofiller loading and ultrasonic amplitudes on rheological, mechanical, electrical, thermal and morphological properties of the nanocomposites was studied. Ultrasonic treatment showed a tremendous decrease in die pressure. Morphological studies showed that ultrasonic treatment improved dispersion of CNFs and CNTs in polymer matrices. PEI/CNFs and PEI/MWNTs nanocomposites were prepared using ultrasound assisted single and twin screw extruder, respectively. A permanent increase in the viscosity, storage and loss modulus and decrease in tan delta was observed with ultrasonic treatment. Ultrasonically treated PEI/CNFs nanocomposites showed a decrease in electrical percolation threshold value as compared to the untreated ones. Breakage of CNFs was observed primarily due to extrusion process alone. In case of PEI/MWNTs nanocomposites, percolation threshold value was found to be between 1 and 2 wt% loading of CNTs for both treated and untreated samples. LCP/CNFs nanocomposites were prepared using ultrasound assisted twin screw extruder with separate feeding of CNFs in the polymer melt. In contrast to behavior of PEI/CNFs and PEI

  4. High-performance hydrogen production and oxidation electrodes with hydrogenase supported on metallic single-wall carbon nanotube networks.

    PubMed

    Svedružić, Draženka; Blackburn, Jeffrey L; Tenent, Robert C; Rocha, John-David R; Vinzant, Todd B; Heben, Michael J; King, Paul W

    2011-03-30

    We studied the electrocatalytic activity of an [FeFe]-hydrogenase from Clostridium acetobutylicum (CaH2ase) immobilized on single-wall carbon nanotube (SWNT) networks. SWNT networks were prepared on carbon cloth by ultrasonic spraying of suspensions with predetermined ratios of metallic and semiconducting nanotubes. Current densities for both proton reduction and hydrogen oxidation electrocatalytic activities were at least 1 order of magnitude higher when hydrogenase was immobilized onto SWNT networks with high metallic tube (m-SWNT) content in comparison to hydrogenase supported on networks with low metallic tube content or when SWNTs were absent. We conclude that the increase in electrocatalytic activities in the presence of SWNTs was mainly due to the m-SWNT fraction and can be attributed to (i) substantial increases in the active electrode surface area, and (ii) improved electronic coupling between CaH2ase redox-active sites and the electrode surface.

  5. High-Performance Hybrid Bismuth-Carbon Nanotube Based Contrast Agent for X-ray CT Imaging.

    PubMed

    Hernández-Rivera, Mayra; Kumar, Ish; Cho, Stephen Y; Cheong, Benjamin Y; Pulikkathara, Merlyn X; Moghaddam, Sakineh E; Whitmire, Kenton H; Wilson, Lon J

    2017-02-22

    Carbon nanotubes (CNTs) have been used for a plethora of biomedical applications, including their use as delivery vehicles for drugs, imaging agents, proteins, DNA, and other materials. Here, we describe the synthesis and characterization of a new CNT-based contrast agent (CA) for X-ray computed tomography (CT) imaging. The CA is a hybrid material derived from ultrashort single-walled carbon nanotubes (20-80 nm long, US-tubes) and Bi(III) oxo-salicylate clusters with four Bi(III) ions per cluster (Bi4C). The element bismuth was chosen over iodine, which is the conventional element used for CT CAs in the clinic today due to its high X-ray attenuation capability and its low toxicity, which makes bismuth a more-promising element for new CT CA design. The new CA contains 20% by weight bismuth with no detectable release of bismuth after a 48 h challenge by various biological media at 37 °C, demonstrating the presence of a strong interaction between the two components of the hybrid material. The performance of the new Bi4C@US-tubes solid material as a CT CA has been assessed using a clinical scanner and found to possess an X-ray attenuation ability of >2000 Hounsfield units (HU).

  6. Graphene-winged carbon nanotubes as high-performance lithium-ion batteries anode with super-long cycle life

    NASA Astrophysics Data System (ADS)

    Ye, Minghui; Hu, Chuangang; Lv, Lingxiao; Qu, Liangti

    2016-02-01

    Graphene-winged carbon nanotubes (G-CNTs) have been prepared by the well-controlled outer-wall peeling of the multi-walled carbon nanotubes (MWCNTs). The final hybrid structure features the few layers of graphene nanosheets attaching to the intact inner walls of CNTs. On one hand, the outer branched graphene nanosheets could suppress the aggregation of CNTs and introduce abundant defects and active-edges for easily accessible chemical interaction. On the other hand, the CNTs could bridge the graphene nanosheets for rapid electron transfer and mechanical robustness. As a result, the G-CNTs was used as the electrode materials exhibiting an extremely steady reversible capacity of 603 mAh g-1 over 2200 cycles at a current density of 1 A g-1 (the corresponding area capacity is 0.16 mAh cm-2 at a current density of 0.26 mA cm-2) and owning a high rate capability much superior to those of the pristine MWCNT-based counterparts. The hierarchical G-CNTs architecture provides a new material platform for development of advanced energy-storage devices.

  7. Mildly reduced less defective graphene oxide/sulfur/carbon nanotube composite films for high-performance lithium-sulfur batteries.

    PubMed

    Li, Rui; Zhang, Miao; Li, Yingru; Chen, Ji; Yao, Bowen; Yu, Mingpeng; Shi, Gaoquan

    2016-04-28

    The microstructures and properties of the carbonaceous matrices in the cathodes of lithium-sulfur (Li-S) batteries have strong effects on their performances. We prepared a ternary composite cathode of mildly reduced less defective graphene oxide (mrLGO), sulfur, and carbon nanotubes (CNTs) by filtration for Li-S batteries. This battery showed a high initial specific capacity of 1219 mA h g(-1) at 0.2 C and a stable specific capacity of around 1000 mA h g(-1) after 200 cycles with a coulombic efficiency of 99%. Its excellent performance is mainly attributed to the good conductivity and residual oxygen containing groups of mrLGO, and the three-dimensional (3D) framework constructed using mrLGO sheets and CNTs.

  8. Atomic layer deposition of ruthenium on plasma-treated vertically aligned carbon nanotubes for high-performance ultracapacitors.

    PubMed

    Kim, Jun Woo; Kim, Byungwoo; Park, Suk Won; Kim, Woong; Shim, Joon Hyung

    2014-10-31

    It is challenging to realize a conformal metal coating by atomic layer deposition (ALD) because of the high surface energy of metals. In this study, ALD of ruthenium (Ru) on vertically aligned carbon nanotubes (CNTs) was carried out. To activate the surface of CNTs that lack surface functional groups essential for ALD, oxygen plasma was applied ex situ before ALD. X-ray photoelectron spectroscopy and Raman spectroscopy confirmed surface activation of CNTs by the plasma pretreatment. Transmission electron microscopy analysis with energy-dispersive x-ray spectroscopy composition mapping showed that ALD Ru grew conformally along CNTs walls. ALD Ru/CNTs were electrochemically oxidized to ruthenium oxide (RuOx) that can be a potentially useful candidate for use in the electrodes of ultracapacitors. Electrode performance of RuOx/CNTs was evaluated using cyclic voltammetry and galvanostatic charge-discharge measurements.

  9. High-performance asymmetric supercapacitor based on nanoarchitectured polyaniline/graphene/carbon nanotube and activated graphene electrodes.

    PubMed

    Shen, Jiali; Yang, Chongyang; Li, Xingwei; Wang, Gengchao

    2013-09-11

    Hierarchical sulfonated graphene nanosheet/carboxylated multiwalled carbon nanotube/polyaniline (sGNS/cMWCNT/PANI) nanocomposites were synthesized through an interfacial polymerization method. Activated porous graphene (aGNS) was prepared by combining chemical foaming, thermal reduction, and KOH activation. Furthermore, we have successfully fabricated an asymmetric supercapacitor (ASC) using sGNS/cMWCNT/PANI and aGNS as the positive and negative electrodes, respectively. Because of its unique structure, high capacitive performance, and complementary potential window, the ASC device can be cycled reversibly at a cell voltage of 1.6 V in a 1 M H2SO4 aqueous electrolyte, delivering a high energy density of 20.5 Wh kg(-1) at a power density of 25 kW kg(-1). Moreover, the ASC device also exhibits a superior long cycle life with 91% retention of the initial specific capacitance after 5000 cycles.

  10. Porous carbon nanotubes decorated with nanosized cobalt ferrite as anode materials for high-performance lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Wang, Lingyan; Zhuo, Linhai; Cheng, Haiyang; Zhang, Chao; Zhao, Fengyu

    2015-06-01

    Generally, the fast ion/electron transport and structural stability dominate the superiority in lithium-storage applications. In this work, porous carbon nanotubes decorated with nanosized CoFe2O4 particles (p-CNTs@CFO) have been rationally designed and synthesized by the assistance of supercritical carbon dioxide (scCO2). When tested as anode materials for lithium-ion batteries, the p-CNTs@CFO composite exhibits outstanding electrochemical behavior with high lithium-storage capacity (1077 mAh g-1 after 100 cycles) and rate capability (694 mAh g-1 at 3 A g-1). These outstanding electrochemical performances are attributed to the synergistic effect of porous p-CNTs and nanosized CFO. Compared to pristine CNTs, the p-CNTs with substantial pores in the tubes possess largely increased specific surface area and rich oxygen-containing functional groups. The porous structure can not only accommodate the volume change during lithiation/delithiation processes, but also provide bicontinuous electron/ion pathways and large electrode/electrolyte interface, which facilitate the ion diffusion kinetics, improving the rate performance. Moreover, the CFO particles are bonded strongly to the p-CNTs through metal-oxygen bridges, which facilitate the electron fast capture from p-CNTs to CFO, and thus resulting in a high reversible capacity and excellent rate performance. Overall, the porous p-CNTs provide an efficient way for ion diffusion and continuous electron transport as anode materials.

  11. Hydroxylated N-doped carbon nanotube-sulfur composites as cathodes for high-performance lithium-sulfur batteries

    NASA Astrophysics Data System (ADS)

    Lee, Jun Seop; Manthiram, Arumugam

    2017-03-01

    Despite the higher energy density than the conventional Li-ion cells at a lower cost, commercialization of Lisbnd S batteries is hindered by the insulating nature of sulfur and the dissolution of intermediate polysulfides (Li2SX, 4 < X ≤ 8) into the electrolyte. We demonstrate here hydroxylated N-doped carbon nanotubes (H-NCNT) as sulfur containers in lithium-sulfur batteries to reduce polysulfide shuttling through an interaction between polysulfides and nitrogen and hydroxyl groups in the H-NCNT. This sulfur-carbon composite electrode with 2.2 mg cm-2 sulfur displays excellent performance with high rate capability (initial capacity of 1341 mAh g-1 at C/5 rate and 849 mAh g-1 at 5C rate), rate stability until 500 cycles (a decay of 0.06% per cycle). Furthermore, a stable reversible capacity of as high as ∼1081 mAh g-1 is realized with a higher sulfur loading of 5.1 mg cm-2.

  12. Nickel cobalt oxide/carbon nanotubes hybrid as a high-performance electrocatalyst for metal/air battery

    NASA Astrophysics Data System (ADS)

    Zhang, Hui; Qiao, Hang; Wang, Haiyan; Zhou, Nan; Chen, Jiajie; Tang, Yougen; Li, Jingsha; Huang, Chenghuan

    2014-08-01

    High-performance, low cost catalyst for oxygen reduction reaction (ORR) remains a big challenge. Herein, nanostructured NiCo2O4/CNTs hybrid was proposed as a high-performance catalyst for metal/air battery for the first time. The well-formed NiCo2O4/CNTs hybrid was studied by steady-state linear polarization curves and galvanostatic discharge curves in comparison with CNTs-free NiCo2O4 and commercial carbon-supported Pt. Because of the synergistic effect, NiCo2O4/CNTs hybrid exhibited significant improvement of catalytic performance in comparison with NiCo2O4 or CNTs alone, even outperforming Pt/C hybrid in ORR process. In addition, the benefits of Ni incorporation were demonstrated by the improved catalytic performance of NiCo2O4/CNTs compared to Co3O4/CNTs, which should be attributed to improved electrical conductivity and new, highly efficient, active sites created by Ni cation incorporation into the spinel structure. NiCo2O4/CNTs hybrid could be used as a promising catalyst for high power metal/air battery.High-performance, low cost catalyst for oxygen reduction reaction (ORR) remains a big challenge. Herein, nanostructured NiCo2O4/CNTs hybrid was proposed as a high-performance catalyst for metal/air battery for the first time. The well-formed NiCo2O4/CNTs hybrid was studied by steady-state linear polarization curves and galvanostatic discharge curves in comparison with CNTs-free NiCo2O4 and commercial carbon-supported Pt. Because of the synergistic effect, NiCo2O4/CNTs hybrid exhibited significant improvement of catalytic performance in comparison with NiCo2O4 or CNTs alone, even outperforming Pt/C hybrid in ORR process. In addition, the benefits of Ni incorporation were demonstrated by the improved catalytic performance of NiCo2O4/CNTs compared to Co3O4/CNTs, which should be attributed to improved electrical conductivity and new, highly efficient, active sites created by Ni cation incorporation into the spinel structure. NiCo2O4/CNTs hybrid could be used as a

  13. Nickel cobalt oxide/carbon nanotubes hybrid as a high-performance electrocatalyst for metal/air battery.

    PubMed

    Zhang, Hui; Qiao, Hang; Wang, Haiyan; Zhou, Nan; Chen, Jiajie; Tang, Yougen; Li, Jingsha; Huang, Chenghuan

    2014-09-07

    High-performance, low cost catalyst for oxygen reduction reaction (ORR) remains a big challenge. Herein, nanostructured NiCo2O4/CNTs hybrid was proposed as a high-performance catalyst for metal/air battery for the first time. The well-formed NiCo2O4/CNTs hybrid was studied by steady-state linear polarization curves and galvanostatic discharge curves in comparison with CNTs-free NiCo2O4 and commercial carbon-supported Pt. Because of the synergistic effect, NiCo2O4/CNTs hybrid exhibited significant improvement of catalytic performance in comparison with NiCo2O4 or CNTs alone, even outperforming Pt/C hybrid in ORR process. In addition, the benefits of Ni incorporation were demonstrated by the improved catalytic performance of NiCo2O4/CNTs compared to Co3O4/CNTs, which should be attributed to improved electrical conductivity and new, highly efficient, active sites created by Ni cation incorporation into the spinel structure. NiCo2O4/CNTs hybrid could be used as a promising catalyst for high power metal/air battery.

  14. A facile approach to prepare porous cup-stacked carbon nanotube with high performance in adsorption of methylene blue.

    PubMed

    Gong, Jiang; Liu, Jie; Jiang, Zhiwei; Wen, Xin; Mijowska, Ewa; Tang, Tao; Chen, Xuecheng

    2015-05-01

    Novel porous cup-stacked carbon nanotube (P-CSCNT) with special stacked morphology consisting of many truncated conical graphene layers was synthesized by KOH activating CSCNT from polypropylene. The morphology, microstructure, textural property, phase structure, surface element composition and thermal stability of P-CSCNT were investigated by field-emission scanning electron microscope, transmission electron microscope (TEM), high-resolution TEM, N2 sorption, X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy and thermal gravimetric analysis. A part of oblique graphitic layers were etched by KOH, and many holes with a diameter of several to a doze of nanometers connecting inner tube with outside were formed, which endowed P-CSCNT with high specific surface area (558.7 m(2)/g), large pore volume (1.993 cm(3)/g) and abundant surface functional groups. Subsequently, P-CSCNT was used for adsorption of methylene blue (MB) from wastewater. Langmuir model closely fitted the adsorption results, and the maximum adsorption capacity of P-CSCNT was as high as 319.1mg/g. This was ascribed to multiple adsorption mechanisms including pore filling, hydrogen bonding, π-π and electrostatic interactions. Pseudo second-order kinetic model was more valid to describe the adsorption behavior. Besides, P-CSCNT showed good recyclablity and reusability. These results demonstrated that P-CSCNT had potential application in wastewater treatment.

  15. Synthesis of carbon nanotube-nickel nanocomposites using atomic layer deposition for high-performance non-enzymatic glucose sensing.

    PubMed

    Choi, Taejin; Kim, Soo Hyeon; Lee, Chang Wan; Kim, Hangil; Choi, Sang-Kyung; Kim, Soo-Hyun; Kim, Eunkyoung; Park, Jusang; Kim, Hyungjun

    2015-01-15

    A useful strategy has been developed to fabricate carbon-nanotube-nickel (CNT-Ni) nanocomposites through atomic layer deposition (ALD) of Ni and chemical vapor deposition (CVD) of functionalized CNTs. Various techniques, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS), were used to characterize the morphology and the structure of as-prepared samples. It was confirmed that the products possess uniform Ni nanoparticles that are constructed by finely controlled deposition of Ni onto oxygen or bromine functionalized CNT surface. Electrochemical studies indicate that the CNT-Ni nanocomposites exhibit high electrocatalytic activity for glucose oxidation in alkaline solutions, which enables the products to be used in enzyme-free electrochemical sensors for glucose determination. It was demonstrated that the CNT-Ni nanocomposite-based glucose biosensor offers a variety of merits, such as a wide linear response window for glucose concentrations of 5 μM-2 mM, short response time (3 s), a low detection limit (2 μM), high sensitivity (1384.1 μA mM(-1) cm(-2)), and good selectivity and repeatability.

  16. A facile and scalable method to prepare carbon nanotube-grafted-graphene for high performance Li-S battery

    NASA Astrophysics Data System (ADS)

    Wang, Q. Q.; Huang, J. B.; Li, G. R.; Lin, Z.; Liu, B. H.; Li, Z. P.

    2017-01-01

    A carbon nanotube-grafted-graphene (CNT-g-Gr) is developed for enhancements of electrical conduction and polysulfide (PS) absorption to improve rate performance and cycleability of lithium-sulfur battery. The CNT-g-Gr is prepared through CNT growth on Ni-deposited graphene sheet which is fabricated via pyrolysis of glucose in a molten salt. The obtained CNT-g-Gr shows much higher specific surface area and PS adsorption capability than graphene. The in-situ formed Ni nanoparticles on graphene sheet not only serve as the catalytic sites for CNT growth, but also function as the anchor-sites for polar PS absorption. The CNT-g-Gr contributes a superb PS adsorption capability arising from graphene and CNT absorbing weakly-polar PS species, and Ni nanoparticles absorbing the species with stronger polarity. The resultant Li-S battery with the CNT-g-Gr shows excellent cycleability and rate performance. A stable discharge capacity of 900 mAh g-1 (with low capacity degradation rate) and a rate capacity of 260 mAh g-1 at 30 C discharge rate have been achieved.

  17. Hierarchically structured Ni(3)S(2)/carbon nanotube composites as high performance cathode materials for asymmetric supercapacitors.

    PubMed

    Dai, Chao-Shuan; Chien, Pei-Yi; Lin, Jeng-Yu; Chou, Shu-Wei; Wu, Wen-Kai; Li, Ping-Hsuan; Wu, Kuan-Yi; Lin, Tsung-Wu

    2013-11-27

    The Ni3S2 nanoparticles with the diameters ranging from 10 to 80 nm are grown on the backbone of conductive multiwalled carbon nanotubes (MWCNTs) using a glucose-assisted hydrothermal method. It is found that the Ni3S2 nanoparticles deposited on MWCNTs disassemble into smaller components after the composite electrode is activated by the consecutive cyclic voltammetry scan in a 2 M KOH solution. Therefore, the active surface area of the Ni3S2 nanoparticles is increased, which further enhances the capacitive performance of the composite electrode. Because the synergistic effect of the Ni3S2 nanoparticles and MWCNTs on the capacitive performance of the composite electrode is pronounced, the composite electrode shows a high specific capacitance of 800 F/g and great cycling stability at a current density of 3.2 A/g. To examine the capacitive performance of the composite electrode in a full-cell configuration, an asymmetric supercapacitor device was fabricated by using the composite of Ni3S2 and MWCNTs as the cathode and activated carbon as the anode. The fabricated device can be operated reversibly between 0 and 1.6 V, and obtain a high specific capacitance of 55.8 F/g at 1 A/g, which delivers a maximum energy density of 19.8 Wh/kg at a power density of 798 W/kg. Furthermore, the asymmetric supercapacitor shows great stability based on the fact that the device retains 90% of its initial capacitance after a consecutive 5000 cycles of galvanostatic charge-discharge performed at a current density of 4 A/g.

  18. Nanomechanics of carbon nanotubes.

    PubMed

    Kis, Andras; Zettl, Alex

    2008-05-13

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

  19. Sustainable design of high-performance microsized microbial fuel cell with carbon nanotube anode and air cathode.

    PubMed

    Mink, Justine E; Hussain, Muhammad Mustafa

    2013-08-27

    Microbial fuel cells (MFCs) are a promising alternative energy source that both generates electricity and cleans water. Fueled by liquid wastes such as wastewater or industrial wastes, the microbial fuel cell converts waste into energy. Microsized MFCs are essentially miniature energy harvesters that can be used to power on-chip electronics, lab-on-a-chip devices, and/or sensors. As MFCs are a relatively new technology, microsized MFCs are also an important rapid testing platform for the comparison and introduction of new conditions or materials into macroscale MFCs, especially nanoscale materials that have high potential for enhanced power production. Here we report a 75 μL microsized MFC on silicon using CMOS-compatible processes and employ a novel nanomaterial with exceptional electrochemical properties, multiwalled carbon nanotubes (MWCNTs), as the on-chip anode. We used this device to compare the usage of the more commonly used but highly expensive anode material gold, as well as a more inexpensive substitute, nickel. This is the first anode material study done using the most sustainably designed microsized MFC to date, which utilizes ambient oxygen as the electron acceptor with an air cathode instead of the chemical ferricyanide and without a membrane. Ferricyanide is unsustainable, as the chemical must be continuously refilled, while using oxygen, naturally found in air, makes the device mobile and is a key step in commercializing this for portable technology such as lab-on-a-chip for point-of-care diagnostics. At 880 mA/m(2) and 19 mW/m(2) the MWCNT anode outperformed the others in both current and power densities with between 6 and 20 times better performance. All devices were run for over 15 days, indicating a stable and high-endurance energy harvester already capable of producing enough power for ultra-low-power electronics and able to consistently power them over time.

  20. [Dispersive solid phase microextraction of vanillins in milk using magnetic nanoparticles of ferroferric oxide/carbon nanotubes combining with high performance liquid chromatography analysis].

    PubMed

    Li, Haifang; Yang, Hongyun; Zhang, Ying; Wang, Peilong; Lin, Jin-Ming

    2014-04-01

    Magnetic nanoparticles of ferroferric oxide/carbon nanotubes (Fe3O4/CNTs) were synthesized by chemically bonding single-walled carbon nanotubes (SWCNTs) to the Fe3O4 nanoparticles. The pretreated carboxyl SWCNTs were modified on the surface of amino-functioned Fe3O4 nanoparticles through the cross-linking reaction between 1-ethyl-3-( 3-dimethylaminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS). The synthesized Fe3O4/CNTs nanoparticles presented high super paramagnetic property and good dispersion ability, and were considered as good candidate adsorbents for dispersive solid phase microextraction. In this work, the synthesized FeO4/CNTs nanoparticles were applied to the extraction of vanillin additives, which was combined with high performance liquid chromatography (HPLC) analysis. The rapid and efficient preconcentration of vanillin and ethyl vanillin from different milk samples were successfully obtained with the detection limits of 10 microg/L and satisfactory recoveries of more than 92%. The results indicated that Fe3O4/CNTs magnetic nanoparticles were good pretreatment alternatives for the concentration of vanillin additives in milk products.

  1. Determination of diethylstilbestrol in milk using carbon nanotube-reinforced hollow fiber solid-phase microextraction combined with high-performance liquid chromatography.

    PubMed

    Yang, Yang; Chen, Juan; Shi, Yan-Ping

    2012-08-15

    Carbon nanotube-reinforced hollow fiber solid-phase microextraction (CNTs-HF-SPME) combined with high-performance liquid chromatography (HPLC) was used to extract and determine diethylstilbestrol (DES) in milk products. Wall pores of the hollow fiber were filled with multi-walled carbon nanotubes (MWCNTs) using sol-gel technology. In the proposed method, DES was selectively extracted by MWCNTs, desorbed to methanol, and analyzed by HPLC. The parameters affecting the efficiency of CNTs-HFSPME, such as the length of the hollow fiber, extraction and desorption times, extraction temperature, stirring rate, pH of the sample solution, and the amount of organic solvent and salt in the sample solution, were investigated and optimized. Under the optimized extraction conditions, the method showed good linearity (24-960 μg L(-1)), a low method detection limit (MDL, 5.1 μg L(-1)), and good recoveries at four different concentrations. It was proven to be simple, rapid, sensitive, and solvent free for the analysis of DES in dairy products.

  2. Hierarchical porous nanocomposite architectures from multi-wall carbon nanotube threaded mesoporous NaTi2(PO4)3 nanocrystals for high-performance sodium electrodes

    NASA Astrophysics Data System (ADS)

    Xu, G. B.; Yang, L. W.; Wei, X. L.; Ding, J. W.; Zhong, J. X.; Chu, P. K.

    2016-09-01

    Rational design and self-assembly of nanostructured electrode materials for high-performance energy-storage devices is highly desirable but still challenging. Herein, we design and synthesize hierarchical porous nanocomposite architectures consisting of mesoporous NaTi2(PO4)3 (MNTP) nanocrystals (NCs) with a pore size of about 10 nm and multi-wall carbon nanotube (MWCNT) networks for high-performance sodium ion batteries (SIBs). Our strategy is based on the hetero-assembly of MWCNTs and nanostructured building units by utilizing the screening effect of electrostatic repulsion in a solution engineered ionic strength using highly soluble ammonium salt to form three-dimensional hierarchical assemblies of MWCNT networks and packed MNTP NCs. Subsequent freeze-drying and calcination convert the assemblies into robust hierarchical porous MWCNTs-threaded particles. Calcination of residual ammonium salt introduces nitrogen into the MWCNTs. Such nanoarchitecture enhances electron/ion conductivity and structural stability as anode materials for SIBs. The nanocomposite has high initial Coulombic efficiency of 99%, high rate capability of 74.0 mAhg-1 at 50C, as well as long-term cycling stability with capacity retention of 74.3 mAhg-1 after 2000 cycles with only 0.012% loss per cycle at 10C. The results provide a general and scalable hetero-assembly approach to different types of nanocomposites for high-performance energy storage devices such as LIBs and SIBs.

  3. Mesoporous Li4Ti5O12 nanoclusters anchored on super-aligned carbon nanotubes as high performance electrodes for lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Sun, Li; Kong, Weibang; Wu, Hengcai; Wu, Yang; Wang, Datao; Zhao, Fei; Jiang, Kaili; Li, Qunqing; Wang, Jiaping; Fan, Shoushan

    2015-12-01

    Mesoporous lithium titanate (LTO) nanoclusters are in situ synthesized in a network of super aligned carbon nanotubes (SACNTs) via a solution-based method followed by heat treatment in air. In the LTO-CNT composite, SACNTs not only serve as the skeleton to support a binder-free electrode, but also render the composite with high conductivity, flexibility, and mechanical strength. The homogeneously dispersed LTO nanoclusters among the SACNTs allow each LTO grain to effectively access the electrolyte and the conductive network, benefiting both ion and electron transport. By the incorporation of LTO into the CNT network, mechanical reinforcement is also achieved. When serving as a negative electrode for lithium ion batteries, such a robust composite-network architecture provides the electrodes with effective charge transport and structural integrity, leading to high-performance flexible electrodes with high capacity, high rate capability, and excellent cycling stability.Mesoporous lithium titanate (LTO) nanoclusters are in situ synthesized in a network of super aligned carbon nanotubes (SACNTs) via a solution-based method followed by heat treatment in air. In the LTO-CNT composite, SACNTs not only serve as the skeleton to support a binder-free electrode, but also render the composite with high conductivity, flexibility, and mechanical strength. The homogeneously dispersed LTO nanoclusters among the SACNTs allow each LTO grain to effectively access the electrolyte and the conductive network, benefiting both ion and electron transport. By the incorporation of LTO into the CNT network, mechanical reinforcement is also achieved. When serving as a negative electrode for lithium ion batteries, such a robust composite-network architecture provides the electrodes with effective charge transport and structural integrity, leading to high-performance flexible electrodes with high capacity, high rate capability, and excellent cycling stability. Electronic supplementary information

  4. Nano-molybdenum carbide/carbon nanotubes composite as bifunctional anode catalyst for high-performance Escherichia coli-based microbial fuel cell.

    PubMed

    Wang, Yaqiong; Li, Bin; Cui, Dan; Xiang, Xingde; Li, Weishan

    2014-01-15

    A novel electrode, carbon felt-supported nano-molybdenum carbide (Mo2C)/carbon nanotubes (CNTs) composite, was developed as platinum-free anode of high performance microbial fuel cell (MFC). The Mo2C/CNTs composite was synthesized by using the microwave-assisted method with Mo(CO)6 as a single source precursor and characterized by using X-ray diffraction and transmission electron microscopy. The activity of the composite as anode electrocatalyst of MFC based on Escherichia coli (E. coli) was investigated with cyclic voltammetry, chronoamperometry, and cell discharge test. It is found that the carbon felt electrode with 16.7 wt% Mo Mo2C/CNTs composite exhibits a comparable electrocatalytic activity to that with 20 wt% platinum as anode electrocatalyst. The superior performance of the developed platinum-free electrode can be ascribed to the bifunctional electrocatalysis of Mo2C/CNTs for the conversion of organic substrates into electricity through bacteria. The composite facilitates the formation of biofilm, which is necessary for the electron transfer via c-type cytochrome and nanowires. On the other hand, the composite exhibits the electrocatalytic activity towards the oxidation of hydrogen, which is the common metabolite of E. coli.

  5. High-performance two-ply yarn supercapacitors based on carbon nanotube yarns dotted with Co3 O4 and NiO nanoparticles.

    PubMed

    Su, Fenghua; Lv, Xiaoming; Miao, Menghe

    2015-02-18

    Yarn supercapacitors are promising power sources for flexible electronic applications that require conventional fabric-like durability and wearer comfort. Carbon nanotube (CNT) yarn is an attractive choice for constructing yarn supercapacitors used in wearable textiles because of its high strength and flexibility. However, low capacitance and energy density limits the use of pure CNT yarn in wearable high-energy density devices. Here, transitional metal oxide pseudocapacitive materials NiO and Co3 O4 are deposited on as-spun CNT yarn surface using a simple electrodeposition process. The Co3 O4 deposited on the CNT yarn surface forms a uniform hybridized CNT@Co3 O4 layer. The two-ply supercapacitors formed from the CNT@Co3 O4 composite yarns display excellent electrochemical properties with very high capacitance of 52.6 mF cm(-2) and energy density of 1.10 μWh cm(-2) . The high performance two-ply CNT@Co3 O4 yarn supercapacitors are mechanically and electrochemically robust to meet the high performance requirements of power sources for wearable electronics.

  6. Synergistic effect of carbon nanofiber/nanotube composite catalyst on carbon felt electrode for high-performance all-vanadium redox flow battery.

    PubMed

    Park, Minjoon; Jung, Yang-jae; Kim, Jungyun; Lee, Ho il; Cho, Jeaphil

    2013-10-09

    Carbon nanofiber/nanotube (CNF/CNT) composite catalysts grown on carbon felt (CF), prepared from a simple way involving the thermal decomposition of acetylene gas over Ni catalysts, are studied as electrode materials in a vanadium redox flow battery. The electrode with the composite catalyst prepared at 700 °C (denoted as CNF/CNT-700) demonstrates the best electrocatalytic properties toward the V(2+)/V(3+) and VO(2+)/VO2(+) redox couples among the samples prepared at 500, 600, 700, and 800 °C. Moreover, this composite electrode in the full cell exhibits substantially improved discharge capacity and energy efficiency by ~64% and by ~25% at 40 mA·cm(-2) and 100 mA·cm(-2), respectively, compared to untreated CF electrode. This outstanding performance is due to the enhanced surface defect sites of exposed edge plane in CNF and a fast electron transfer rate of in-plane side wall of the CNT.

  7. Heterostructured core-shell ZnMn₂O₄ nanosheets@carbon nanotubes' coaxial nanocables: a competitive anode towards high-performance Li-ion batteries.

    PubMed

    Yuan, Changzhou; Zhang, Longhai; Zhu, Siqi; Cao, Hui; Lin, Jingdong; Hou, Linrui

    2015-04-10

    In this study, we rationally designed a rapid, low-temperature yet general synthetic methodology for the first time, involving in situ growth of two-dimensional (2D) birnessite-type MnO2 nanosheets (NSs) upon each carbon nanotube (CNT), and we designed the subsequent phase transformation into untrathin mesoporous ZnMn2O4 NSs with a thickness of ∼2-3 nm at room temperature to efficiently fabricate heterostructured core-shell ZnMn2O4 NSs@CNT coaxial nanocables with well-dispersed and tunable ZnMn2O4 loading. The underlying insights into the low-temperature formation mechanism of the unique core-shell hybrid nanoarchitectures were tentatively proposed here. When utilized as a high-performance anode for advanced LIBs, the resultant core-shell ZnMn2O4@CNTs' coaxial nanocables (∼84.5 wt.% loading) exhibited large specific discharge capacity (∼1033 mAh g(-1)), good rate capability (∼528 mAh g(-1)) and excellent cycling stability (average capacity degradation of only ∼5.2% per cycle) at a high current rate of 1224 mA g(-1), originating from the distinct core-shell synergetic effect of fast electronic delivery and from the large electrode/electrolyte contacting surfaces/interfaces provided by three-dimensional entangling coaxial CNT-based nanonetwork topology.

  8. A layer-nanostructured assembly of PbS quantum dot/multiwalled carbon nanotube for a high-performance photoswitch

    PubMed Central

    Feng, Wei; Qin, Chengqun; Shen, Yongtao; Li, Yu; Luo, Wen; An, Haoran; Feng, Yiyu

    2014-01-01

    A layered nanostructure of a lead sulfide (PbS) quantum dot (QD)/multi-walled carbon nanotube (MWNT) hybrid was prepared by the electrostatic assembly after the phase transfer of PbS QDs from an organic to an aqueous phase. Well-crystallized PbS QDs with a narrow diameter (5.5 nm) was mono-dispersed on the sidewalls of MWNT by the electrostatic adsorption. Near-infrared absorption of PbS/MWNT nanostructures was improved and controlled by the packing density of PbS QDs. Efficient charge transfer between PbS and MWNT at the interface resulted in a remarkable quenching of photoluminescence up to 28.6% and a blue-shift of emission band by 300 nm. This feature was facilitated by band energy levels based on the intimate contact through the electrostatic interaction. Two-terminal devices using PbS/MWNT nanostructures showed an excellent on/off switching photocurrent and good stability during 20 cycles under light illumination due to electron transfer from PbS to MWNT. The photoswitch exhibited a high photo sensitivity up to 31.3% with the photocurrent of 18.3 μA under the light of 3.85 mW/cm2, which outperformed many QD/carbon-based nanocomposites. Results indicate that the electrostatic layered assembly of QD/MWNT nanostructure is an excellent platform for the fabrication of high-performance optoelectronic devices. PMID:24445285

  9. High performance ultracapacitors with carbon nanomaterials and ionic liquids

    DOEpatents

    Lu, Wen; Henry, Kent Douglas

    2012-10-09

    The present invention is directed to the use of carbon nanotubes and/or electrolyte structures in various electrochemical devices, such as ultracapacitors having an ionic liquid electrolyte. The carbon nanotubes are preferably aligned carbon nanotubes. Compared to randomly entangled carbon nanotubes, aligned carbon nanotubes can have better defined pore structures and higher specific surface areas.

  10. A simple L-cysteine-assisted method for the growth of MoS2 nanosheets on carbon nanotubes for high-performance lithium ion batteries.

    PubMed

    Park, Seung-Keun; Yu, Seung-Ho; Woo, Seunghee; Quan, Bo; Lee, Dong-Chan; Kim, Min Kun; Sung, Yung-Eun; Piao, Yuanzhe

    2013-02-21

    We introduce a simple process to synthesize few-layered MoS(2) nanosheets supported on coaxial carbon nanotubes through an L-cysteine-assisted hydrothermal route, in which L-cysteine, a cheap and ordinary amino acid, plays a fundamental role in controlling the morphology of the hybrid material and the binder to help the growth of MoS(2) nanosheets on the surface of the carbon nanotubes. It is also demonstrated that the polypeptide formed by L-cysteine can be transformed into amorphous carbon by heat treatment under an inert atmosphere. The materials exhibit high capacity and excellent cycling performance when used as anode materials for lithium ion batteries. The specific capacity of a composite with 1 : 4 molar ratio of MoS(2) to carbon nanotubes is 736.5 mAh g(-1) after the first cycle, increased for several initial cycles, and remains at 823.4 mAh g(-1) even after 30 cycles, when cycled at a current density of 100 mA g(-1). At a very high current density of 1600 mA g(-1), the material shows a stable capacity of approximately 530 mAh g(-1) after 30 cycles. The noteworthy improvement in the electrochemical performance of the material can be attributed to their unique structure and the synergistic effects of amorphous carbon and few-layered MoS(2).

  11. Determination of beta-carboline alkaloids in foods and beverages by high-performance liquid chromatography with electrochemical detection at a glassy carbon electrode modified with carbon nanotubes.

    PubMed

    Agüí, Lourdes; Peña-Farfal, Carlos; Yáñez-Sedeño, Paloma; Pingarrón, José M

    2007-03-07

    Simple and sensitive methods for the separation and quantification of beta-carboline alkaloids in foods and beverages by HPLC with electrochemical detection at carbon nanotubes-modified glassy carbon electrodes (CNTs-GCE) are reported. Electrode modification with multi-wall CNTs produced an improved amperometric response to beta-carbolines, in spite of the working medium consisting of methanol:acetonitrile: 0.05 mol L(-1) Na(2)HPO(4) solution of pH 9.0 (20:20:60). On the contrary to that observed at a bare GCE, a good repeatability of the amperometric measurements carried out at +900 mV versus Ag/AgCl (R.S.D. of 3.2% for i(p), n=20) was achieved at the CNTs-GCE. Using an Ultrabase C(18) column and isocratic elution with the above mentioned mobile phase, a complete resolution of the chromatographic peaks for harmalol, harmaline, norharmane, harmane and harmine, was achieved. Calibration graphs over the 0.25-100 microM range with detection limits ranging between 4 and 19 ng mL(-1), were obtained. The HPLC-ED at CNTs-GCE method was applied to the analysis of beer, coffee and cheese samples, spiked with beta-carbolines at concentration levels corresponding to those may be found in the respective samples. The steps involved in sample treatment, such as extraction and clean-up, were optimized for each type of sample. Recoveries ranging between 92 and 102% for beer, 92 and 101% for coffee, and 88 and 100% for cheese, at sub-microg mL(-1) or g(-1) analytes concentration levels were achieved.

  12. Carbon nanotube composite materials

    DOEpatents

    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.

  13. Freeze-drying synthesis of three-dimensional porous LiFePO4 modified with well-dispersed nitrogen-doped carbon nanotubes for high-performance lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Tu, Xiaofeng; Zhou, Yingke; Song, Yijie

    2017-04-01

    The three-dimensional porous LiFePO4 modified with uniformly dispersed nitrogen-doped carbon nanotubes has been successfully prepared by a freeze-drying method. The morphology and structure of the porous composites are characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), and the electrochemical performances are evaluated using the constant current charge/discharge tests, cyclic voltammetry and electrochemical impedance spectroscopy. The nitrogen-doped carbon nanotubes are uniformly dispersed inside the porous LiFePO4 to construct a superior three-dimensional conductive network, which remarkably increases the electronic conductivity and accelerates the diffusion of lithium ion. The porous composite displays high specific capacity, good rate capability and excellent cycling stability, rendering it a promising positive electrode material for high-performance lithium-ion batteries.

  14. 3D well-interconnected NiO-graphene-carbon nanotube nanohybrids as high-performance anode materials for Li-ion batteries

    NASA Astrophysics Data System (ADS)

    Zhang, Zhifeng; Zhang, Xia; You, Xiaolong; Zhang, Mengyuan; Walle, Maru Dessie; Wang, Juan; Li, Yajuan; Liu, You-Nian

    2016-08-01

    3D carbon scaffold built from carbon nanotubes (CNTs) and graphene exhibits the synergistic effects in electronic conductivity and buffers the structural strain of materials. In this paper, NiO-graphene-carbon nanotubes (NiO-G-CNTs) nanohybrids were prepared via a facile hydrothermal-thermal decomposition process. The as-prepared ternary component nanohybrids exhibit high reversible specific capacity, improved cycling stability, and excellent rate capability, compared to those of NiO-graphene hybrids and pure NiO. The NiO-G-CNT electrode reveals a specific capacity of 858.1 mA h g-1 after 50 cycles at a current density of 100 mA g-1. At a higher current density of 1000 mA g-1, it still reveals a specific capacity of 676 mA h g-1 after 40 cycles. This outstanding electrochemical performance is attributed to its special 3D network structures, where the NiO nanoparticles are well distributed on the surface of graphene sheets, with the CNTs interwoven between individual graphene sheets. This special structure effectively prevents the restacking of graphene sheets and affords an easy route for the transport of electrons and ions.

  15. Top-Contact Self-Aligned Printing for High-Performance Carbon Nanotube Thin-Film Transistors with Sub-Micron Channel Length.

    PubMed

    Cao, Xuan; Wu, Fanqi; Lau, Christian; Liu, Yihang; Liu, Qingzhou; Zhou, Chongwu

    2017-02-28

    Semiconducting single-wall carbon nanotubes are ideal semiconductors for printed thin-film transistors due to their excellent electrical performance and intrinsic printability with solution-based deposition. However, limited by resolution and registration accuracy of current printing techniques, previously reported fully printed nanotube transistors had rather long channel lengths (>20 μm) and consequently low current-drive capabilities (<0.2 μA/μm). Here we report fully inkjet printed nanotube transistors with dramatically enhanced on-state current density of ∼4.5 μA/μm by downscaling the devices to a sub-micron channel length with top-contact self-aligned printing and employing high-capacitance ion gel as the gate dielectric. Also, the printed transistors exhibited a high on/off ratio of ∼10(5), low-voltage operation, and good mobility of ∼15.03 cm(2) V(-1)s(-1). These advantageous features of our printed transistors are very promising for future high-definition printed displays and sensing systems, low-power consumer electronics, and large-scale integration of printed electronics.

  16. Carbon nanotube nanoelectrode arrays

    DOEpatents

    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.

  17. Growth of ultrathin MoS₂ nanosheets with expanded spacing of (002) plane on carbon nanotubes for high-performance sodium-ion battery anodes.

    PubMed

    Zhang, Shen; Yu, Xianbo; Yu, Hailong; Chen, Yujin; Gao, Peng; Li, Chunyan; Zhu, Chunling

    2014-12-24

    A hydrothermal method was developed to grow ultrathin MoS2 nanosheets, with an expanded spacing of the (002) planes, on carbon nanotubes. When used as a sodium-ion battery anode, the composite exhibited a specific capacity of 495.9 mAh g(-1), and 84.8% of the initial capacity was retained after 80 cycles, even at a current density of 200 mA g(-1). X-ray diffraction analyses show that the sodiation/desodiation mechanismis based on a conversion reaction. The high capacity and long-term stability at a high current ate demonstrate that the composite is a very promising candidate for use as an anode material in sodium-ion batteries.

  18. High performance all-carbon thin film supercapacitors

    NASA Astrophysics Data System (ADS)

    Liu, Jinzhang; Mirri, Francesca; Notarianni, Marco; Pasquali, Matteo; Motta, Nunzio

    2015-01-01

    We fabricated high performance supercapacitors by using all carbon electrodes, with volume energy in the order of 10-3 Whcm-3, comparable to Li-ion batteries, and power densities in the range of 10 Wcm-3, better than laser-scribed-graphene supercapacitors. All-carbon supercapacitor electrodes are made by solution processing and filtering electrochemically-exfoliated graphene sheets mixed with clusters of spontaneously entangled multiwall carbon nanotubes. We maximize the capacitance by using a 1:1 weight ratio of graphene to multi-wall carbon nanotubes and by controlling their packing in the electrode film so as to maximize accessible surface and further enhance the charge collection. This electrode is transferred onto a plastic-paper-supported double-wall carbon nanotube film used as current collector. These all-carbon thin films are combined with plastic paper and gelled electrolyte to produce solid-state bendable thin film supercapacitors. We assembled supercapacitor cells in series in a planar configuration to increase the operating voltage and find that the shape of our supercapacitor film strongly affects its capacitance. An in-line superposition of rectangular sheets is superior to a cross superposition in maintaining high capacitance when subject to fast charge/discharge cycles. The effect is explained by addressing the mechanism of ion diffusion into stacked graphene sheets.

  19. Platinum-TM (TM = Fe, Co) alloy nanoparticles dispersed nitrogen doped (reduced graphene oxide-multiwalled carbon nanotube) hybrid structure cathode electrocatalysts for high performance PEMFC applications.

    PubMed

    Vinayan, B P; Ramaprabhu, S

    2013-06-07

    The efforts to push proton exchange membrane fuel cells (PEMFC) for commercial applications are being undertaken globally. In PEMFC, the sluggish kinetics of oxygen reduction reactions (ORR) at the cathode can be improved by the alloying of platinum with 3d-transition metals (TM = Fe, Co, etc.) and with nitrogen doping, and in the present work we have combined both of these aspects. We describe a facile method for the synthesis of a nitrogen doped (reduced graphene oxide (rGO)-multiwalled carbon nanotubes (MWNTs)) hybrid structure (N-(G-MWNTs)) by the uniform coating of a nitrogen containing polymer over the surface of the hybrid structure (positively surface charged rGO-negatively surface charged MWNTs) followed by the pyrolysis of these (rGO-MWNTs) hybrid structure-polymer composites. The N-(G-MWNTs) hybrid structure is used as a catalyst support for the dispersion of platinum (Pt), platinum-iron (Pt3Fe) and platinum-cobalt (Pt3Co) alloy nanoparticles. The PEMFC performances of Pt-TM alloy nanoparticle dispersed N-(G-MWNTs) hybrid structure electrocatalysts are 5.0 times higher than that of commercial Pt-C electrocatalysts along with very good stability under acidic environment conditions. This work demonstrates a considerable improvement in performance compared to existing cathode electrocatalysts being used in PEMFC and can be extended to the synthesis of metal, metal oxides or metal alloy nanoparticle decorated nitrogen doped carbon nanostructures for various electrochemical energy applications.

  20. A new strategy for designing high-performance sulfonated poly(ether ether ketone) polymer electrolyte membranes using inorganic proton conductor-functionalized carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Gong, Chunli; Zheng, Xuan; Liu, Hai; Wang, Guangjin; Cheng, Fan; Zheng, Genwen; Wen, Sheng; Law, Wing-Cheung; Tsui, Chi-Pong; Tang, Chak-Yin

    2016-09-01

    Remarkable progress has been made on the use of polymer electrolyte membranes (PEMs) for renewable-energy-related research. In particular, carbon nanotubes (CNTs) have emerged as versatile nanomaterials to modify PEMs. However, the inert ionic conduction ability and possible short-circuiting risk are the two major obstacles to their further development. In this work, CNTs are firstly functionalized with an inorganic proton conductor, boron phosphate (BPO4), using a facile polydopamine-assisted sol-gel method to yield BPO4@CNTs. This new additive is then used to modify sulfonated poly(ether ether ketone) (SPEEK). Polydopamine coating layer can act as an extraordinary glue to homogeneously adhere BPO4 nanoparticles on CNTs, thereby not only reducing the risk of short-circuiting, but also fabricating new proton-conducting pathways in the composite membranes. A comprehensive characterization reveals that the thermal stability, tensile properties, and dimensional stability of PEMs are significantly improved. Compared with pure SPEEK, the proton conductivity of SPEEK/BPO4@CNTs-2 is improved by 45% and 150% at 20 °C and at 80 °C, respectively. Furthermore, the H2/O2 cell performance of SPEEK/BPO4@CNTs-2 membrane exhibits a peak power density of 340.7 mW cm-2 at 70 °C, which is significantly better than that of pure SPEEK (254.2 mW cm-2), demonstrating the great potential of proton conductors-functionalized CNTs in PEMs.

  1. BaFe12O19-chitosan Schiff-base Ag (I) complexes embedded in carbon nanotube networks for high-performance electromagnetic materials

    PubMed Central

    Zhao, Jie; Xie, Yu; Guan, Dongsheng; Hua, Helin; Zhong, Rong; Qin, Yuancheng; Fang, Jing; Liu, Huilong; Chen, Junhong

    2015-01-01

    The multiwalled carbon nanotubes/BaFe12O19-chitosan (MCNTs/BF-CS) Schiff base Ag (I) complex composites were synthesized successfully by a chemical bonding method. The morphology and structures of the composites were characterized with electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction techniques. Their conductive properties were measured using a four-probe conductivity tester at room temperature, and their magnetic properties were tested by a vibrating sample magnetometer. The results show that the BF-CS Schiff base Ag (I) complexes are embedded into MCNT networks. When the mass ratio of MCNTs and BF-CS Schiff base is 0.95:1, the conductivity, Ms (saturation magnetization), Mr (residual magnetization), and Hc (coercivity) of the BF-CS Schiff base composites reach 1.908 S cm−1, 28.20 emu g−1, 16.66 emu g−1 and 3604.79 Oe, respectively. Finally, a possible magnetic mechanism of the composites has also been proposed. PMID:26218269

  2. Self-Assembly of Polyethylene Glycol-Grafted Carbon Nanotube/Sulfur Composite with Nest-like Structure for High-Performance Lithium-Sulfur Batteries.

    PubMed

    Li, Han; Sun, Liping; Wang, Gengchao

    2016-03-09

    The novel polyethylene glycol-grafted multiwalled carbon nanotube/sulfur (PEG-CNT/S) composite cathodes with nest-like structure are fabricated through a facile combination process of liquid phase deposition and self-assembly, which consist of the active material core of sulfur particle and the conductive shell of PEG-CNT network. The unique architecture not only provides a short and rapid charge transfer pathway to improve the reaction kinetics but also alleviates the volume expansion of sulfur during lithiation and minimizes the diffusion of intermediate polysulfides. Such an encouraging electrochemical environment ensures the excellent rate capability and high cycle stability. As a result, the as-prepared PEG-CNT/S composite with sulfur content of 75.9 wt % delivers an initial discharge capacity of 1191 and 897 mAh g(-1) after 200 cycles at 0.2 C with an average Coulombic efficiency of 99.5%. Even at a high rate of 2 C, an appreciable capacity of 723 mAh g(-1) can still be obtained.

  3. Three-Dimensional Graphene/Single-Walled Carbon Nanotube Aerogel Anchored with SnO2 Nanoparticles for High Performance Lithium Storage.

    PubMed

    Wang, Jing; Fang, Fang; Yuan, Tao; Yang, Junhe; Chen, Liang; Yao, Chi; Zheng, Shiyou; Sun, Dalin

    2017-02-01

    A unique 3D graphene-single walled carbon nanotube (G-SWNT) aerogel anchored with SnO2 nanoparticles (SnO2@G-SWCNT) is fabricated by the hydrothermal self-assembly process. The influences of mass ratio of SWCNT to graphene on structure and electrochemical properties of SnO2@G-SWCNT are investigated systematically. The SnO2@G-SWCNT composites show excellent electrochemical performance in Li-ion batteries; for instance, at a current density of 100 mA g(-1), a specific capacity of 758 mAh g(-1) was obtained for the SnO2@G-SWCNT with 50% SWCNT in G-SWCNT and the Coulombic efficiency is close to 100% after 200 cycles; even at current density of 1 A g(-1), it can still maintain a stable specific capacity of 537 mAh g(-1) after 300 cycles. It is believed that the 3D G-SWNT architecture provides a flexible conductive matrix for loading the SnO2, facilitating the electronic and ionic transportation and mitigating the volume variation of the SnO2 during lithiation/delithiation. This work also provides a facile and reasonable strategy to solve the pulverization and agglomeration problem of other transition metal oxides as electrode materials.

  4. High performance of carbon nanotubes/silver nanowires-PET hybrid flexible transparent conductive films via facile pressing-transfer technique.

    PubMed

    Jing, Mao-Xiang; Han, Chong; Li, Min; Shen, Xiang-Qian

    2014-01-01

    To obtain low sheet resistance, high optical transmittance, small open spaces in conductive networks, and enhanced adhesion of flexible transparent conductive films, a carbon nanotube (CNT)/silver nanowire (AgNW)-PET hybrid film was fabricated by mechanical pressing-transfer process at room temperature. The morphology and structure were characterized by scanning electron microscope (SEM) and atomic force microscope (AFM), the optical transmittance and sheet resistance were tested by ultraviolet-visible spectroscopy (UV-vis) spectrophotometer and four-point probe technique, and the adhesion was also measured by 3M sticky tape. The results indicate that in this hybrid nanostructure, AgNWs form the main conductive networks and CNTs as assistant conductive networks are filled in the open spaces of AgNWs networks. The sheet resistance of the hybrid films can reach approximately 20.9 to 53.9 Ω/□ with the optical transmittance of approximately 84% to 91%. The second mechanical pressing step can greatly reduce the surface roughness of the hybrid film and enhance the adhesion force between CNTs, AgNWs, and PET substrate. This process is hopeful for large-scale production of high-end flexible transparent conductive films.

  5. Cross-stacked carbon nanotube film as an additional built-in current collector and adsorption layer for high-performance lithium sulfur batteries

    NASA Astrophysics Data System (ADS)

    Sun, Li; Kong, Weibang; Li, Mengya; Wu, Hengcai; Jiang, Kaili; Li, Qunqing; Zhang, Yihe; Wang, Jiaping; Fan, Shoushan

    2016-02-01

    Cross-stacked carbon nanotube (CNT) film is proposed as an additional built-in current collector and adsorption layer in sulfur cathodes for advanced lithium sulfur (Li-S) batteries. On one hand, the CNT film with high conductivity, microstructural rough surface, high flexibility and mechanical durability retains stable and direct electronic contact with the sulfur cathode materials, therefore decreasing internal resistivity and suppressing polarization of the cathode. On the other hand, the highly porous structure and the high surface area of the CNT film provide abundant adsorption points to support and confine sulfur cathode materials, alleviate their aggregation and promote high sulfur utilization. Moreover, the lightweight and compact structure of the CNT film adds no extra weight or volume to the sulfur cathode, benefitting the improvement of energy densities. Based on these characteristics, the sulfur cathode with a 100-layer cross-stacked CNT film presents excellent rate performances with capacities of 986, 922 and 874 mAh g-1 at cycling rates of 0.2C, 0.5C and 1C for sulfur loading of 60 wt%, corresponding to an improvement of 52%, 109% and 146% compared to that without a CNT film. Promising cycling performances are also demonstrated, offering great potential for scaled-up production of sulfur cathodes for Li-S batteries.

  6. High-performance semiconducting nanotube inks: progress and prospects.

    PubMed

    Rouhi, Nima; Jain, Dheeraj; Burke, Peter John

    2011-11-22

    While the potential for high mobility printed semiconducting nanotube inks has been clear for over a decade, a myriad of scientific and technological issues has prevented commercialization and practical use. One of the most challenging scientific problems has been to understand the relationship between the pristine, individual nanotube mobility (known to be in the 10,000 cm(2)/V·s range) and the as-deposited random network mobility (recently demonstrated in the 100 cm(2)/V·s range). An additional significant scientific hurdle has been to understand, manage, and ultimately eliminate the effects of metallic nanotubes on the network performance, specifically the on/off ratio. Additional scientific progress is important in understanding the dependence of nanotube length, diameter, and density on device performance. Finally, the development of ink formulations that are of practical use in manufacturing is of paramount importance, especially with regard to drying time and uniformity, and ultimately, the issue of scalability and cost must be addressed. Many of these issues have recently been investigated from a phenomenological point of view, and a comprehensive understanding is beginning to emerge. In this paper, we present an overview of solution-based printed carbon nanotube devices and discuss long-term technology prospects. While significant technical challenges still remain, it is clear that the prospects for the use of nanotube ink in a myriad of systems is feasible given their unmatched mobility and compatibility with heterogeneous integration into a variety of applications in printed and flexible electronics.

  7. Functionalization of carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Korneva, Guzeliya

    Carbon nanotubes have unique properties that make them attractive for different engineering applications. However, because of their chemical inertness, carbon nanotubes have to be functionalized in order to acquire additional physico-chemical properties. Large multiwalled carbon nanotubes are different from fullerenes and singlewalled nanotubes because the stresses in their walls are almost relaxed while most chemical methods for fullerene functionalization exploit this effect of stressed bonds. The objective of this work is to develop new methods for functionalization of multiwalled carbon nanotubes. This work is dedicated to study two functionalization methods. The first deals with physico-chemical functionalization by filling the nanotube interior with colloidal suspensions. Irreversible adsorption of functional nanoparticles on the nanotube wall leads to the nanotube functionalization. The second method is purely chemical functionalization, which uses the reaction of cyclopropanation to break pi-bonds in the benzene rings of the nanotubes with formation of new σ-bonds with deprotonated malonate. This so-called Bingel reaction has been used in fullerene chemistry and in this work was applied for the first time to functionalize multiwalled carbon nanotubes. While capillary filling of carbon nanotubes was known long ago, the research community was skeptical about possibility of engulfing nanoparticles into nanotubes by capillary forces. We developed and implemented capillary method to fill nanotubes with different nanoparticles. Using this method, magnetic carbon nanotubes were produced for the first time. Synthesized nanotubes have very high magnetic moment and allow to manipulate them by magnetic field. These magnetic nanotubes have been successfully used in fabrication of carbon nanotube-tipped pipettes for biological probes. The Bingel reaction was studied on three sets of multiwalled carbon nanotubes with diameters: 20nm, 100nm, and 300nm. To estimate the

  8. Hierarchical Assembly of α-Fe2O3 Nanorods on Multiwall Carbon Nanotubes as a High-Performance Sensing Material for Gas Sensors.

    PubMed

    Dai, Mingjun; Zhao, Liupeng; Gao, Hongyu; Sun, Peng; Liu, Fengmin; Zhang, Sean; Shimanoe, Kengo; Yamazoe, Noboru; Lu, Geyu

    2017-03-15

    This paper presents a facile hydrolysis reaction and annealing for preparing a novel hierarchical nanoheterostructure via assembly of α-Fe2O3 nanorods onto multiwall carbon nanotubes (MWCNTs) backbones. The as-synthesized nanocomposites were characterized using XRD (X-ray diffraction), FESEM (Field emission scanning electron microscopy), TEM (Transmission electron microscopy), XPS (X-ray photoelectron spectroscopy) and BET (Surface Area and Porosity System). The observations showed uniform α-Fe2O3 nanorods approximately 100-200 nm in length and 50-100 nm in diameter that were hierarchically assembled onto the surface of the MWCNTs. The formation of the heterostructure was investigated by observing the evolution of the microstructure of the products at different reaction times. The X-ray photoelectron spectra (XPS) showed that the ability of the absorbing oxygen was enhanced by the formation of the heterostructure composites. Moreover, as a proof-of-concept presentation, the novel CNTs@α-Fe2O3 hierarchical heterostructure acted as a gas sensitive material. Significantly, the composites exhibited excellent sensing properties for acetone with high sensitivity, exceptional selectivity and good reproducibility. The response of the CNTs@α-Fe2O3 sensor to 100 ppm acetones at 225 °C was nearly 35, which was superior to the single α-Fe2O3 nanorods with a response of 16, and the detection limit of the sensor was 500 ppb. The enhanced properties were mainly attributed to the unique structure and p-n heterojunction between the CNTs and the α-Fe2O3 nanorods.

  9. Reinforced Carbon Nanotubes.

    DOEpatents

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

    2005-06-28

    The present invention relates generally to reinforced carbon nanotubes, and more particularly to reinforced carbon nanotubes having a plurality of microparticulate carbide or oxide materials formed substantially on the surface of such reinforced carbon nanotubes composite materials. 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.

  10. Hemotoxicity of carbon nanotubes.

    PubMed

    Bussy, Cyrill; Methven, Laura; Kostarelos, Kostas

    2013-12-01

    Carbon nanotubes may enter into the bloodstream and interact with blood components indirectly via translocation following unintended exposure or directly after an intended administration for biomedical purposes. Once introduced into systemic circulation, nanotubes will encounter various proteins, biomolecules or cells which have specific roles in the homeostasis of the circulatory system. It is therefore essential to determine whether those interactions will lead to adverse effects or not. Advances in the understanding of how carbon nanotubes interact with blood proteins, the complement system, red blood cells and the hemostatic system are reviewed in this article. While many studies on carbon nanotube health risk assessment and their biomedical applications have appeared in the last few years, reports on the hemocompatibility of these nanomaterials remain surprisingly limited. Yet, defining the hemotoxicological profile is a mandatory step toward the development of clinically-relevant medications or contrast agents based on carbon nanotubes.

  11. High-performance nanotube-enhanced perovskite photodetectors.

    PubMed

    Ka, Ibrahima; Gerlein, Luis Felipe; Nechache, Riad; Cloutier, Sylvain G

    2017-03-30

    Organic-inorganic perovskites have already shown a tremendous potential for low-cost light-harvesting devices. Yet, the relatively low carrier mobilities in bulk perovskites still prevent large-area devices with performances competing with state-of-the-art technologies. Here, we tackle this fundamental challenge by incorporating single-wall carbon nanotubes within a perovskite matrix by means of a simple two-step method in ambient air. Using this nano-engineered hybrid film, we demonstrate large-area photodetectors with responsivities up-to 13.8 A.W(-1) and a broad spectral response from 300 to 800 nm, indicating that photocurrent generation arises from the charge transfer from the perovskite matrix to the embedded nanotube network. As the nanotubes facilitate the carrier extraction, these photodetectors also show a fast response time of 10 ms. This is significantly faster than most of previous reports on perovskite-based photodetectors, including devices with much smaller photosensitive areas. This approach is also well-suited for large-scale production of other perovskite-based light-harvesting devices.

  12. High-performance nanotube-enhanced perovskite photodetectors

    PubMed Central

    Ka, Ibrahima; Gerlein, Luis Felipe; Nechache, Riad; Cloutier, Sylvain G.

    2017-01-01

    Organic-inorganic perovskites have already shown a tremendous potential for low-cost light-harvesting devices. Yet, the relatively low carrier mobilities in bulk perovskites still prevent large-area devices with performances competing with state-of-the-art technologies. Here, we tackle this fundamental challenge by incorporating single-wall carbon nanotubes within a perovskite matrix by means of a simple two-step method in ambient air. Using this nano-engineered hybrid film, we demonstrate large-area photodetectors with responsivities up-to 13.8 A.W−1 and a broad spectral response from 300 to 800 nm, indicating that photocurrent generation arises from the charge transfer from the perovskite matrix to the embedded nanotube network. As the nanotubes facilitate the carrier extraction, these photodetectors also show a fast response time of 10 ms. This is significantly faster than most of previous reports on perovskite-based photodetectors, including devices with much smaller photosensitive areas. This approach is also well-suited for large-scale production of other perovskite-based light-harvesting devices. PMID:28358041

  13. Electrostatic interactions for directed assembly of high performance nanostructured energetic materials of Al/Fe2O3/multi-walled carbon nanotube (MWCNT)

    NASA Astrophysics Data System (ADS)

    Zhang, Tianfu; Ma, Zhuang; Li, Guoping; Wang, Zhen; Zhao, Benbo; Luo, Yunjun

    2016-05-01

    Electrostatic self-assembly in organic solvent without intensively oxidative or corrosive environments, was adopted to prepare Al/Fe2O3/MWCNT nanostructured energetic materials as an energy generating material. The negatively charged MWCNT was used as a glue-like agent to direct the self-assembly of the well dispersed positively charged Al (fuel) and Fe2O3 (oxide) nanoparticles. This spontaneous assembly method without any surfactant chemistry or other chemical and biological moieties decreased the aggregation of the same nanoparticles largely, moreover, the poor interfacial contact between the Al (fuel) and Fe2O3 (oxide) nanoparticles was improved significantly, which was the key characteristic of high performance nanostructured energetic materials. In addition, the assembly process was confirmed as Diffusion-Limited Aggregation. The assembled Al/Fe2O3/MWCNT nanostructured energetic materials showed excellent performance with heat release of 2400 J/g, peak pressure of 0.42 MPa and pressurization rate of 105.71 MPa/s, superior to that in the control group Al/Fe2O3 nanostructured energetic materials prepared by sonication with heat release of 1326 J/g, peak pressure of 0.19 MPa and pressurization rate of 33.33 MPa/s. Therefore, the approach, which is facile, opens a promising route to the high performance nanostructured energetic materials.

  14. Transport in Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

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

    1999-01-01

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

  15. Carbon nanotubes: Fibrillar pharmacology

    NASA Astrophysics Data System (ADS)

    Kostarelos, Kostas

    2010-10-01

    The mechanisms by which chemically functionalized carbon nanotubes flow in blood and are excreted through the kidneys illustrate the unconventional behaviour of these fibrillar nanostructures, and the opportunities they offer as components for the design of advanced delivery vehicles.

  16. Carbon nanotube solar cells.

    PubMed

    Klinger, Colin; Patel, Yogeshwari; Postma, Henk W Ch

    2012-01-01

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

  17. Determination of pyrazole and pyrrole pesticides in environmental water samples by solid-phase extraction using multi-walled carbon nanotubes as adsorbent coupled with high-performance liquid chromatography.

    PubMed

    Ma, Jiping; Lu, Xi; Xia, Yan; Yan, Fengli

    2015-02-01

    A solid-phase extraction (SPE) method using multi-walled carbon nanotubes as adsorbent coupled with high-performance liquid chromatography was developed for the determination of four pyrazole and pyrrole pesticides (fenpyroximate, chlorfenapyr, fipronil and flusilazole) in environmental water samples. Several parameters, such as extraction adsorbent, elution solvent and volume and sample loading flow rate were optimized to obtain high SPE recoveries and extraction efficiency. The calibration curves for the pesticides extracted were linear in the range of 0.05-10 μg L(-1) for chlorfenapyr and fenpyroximate and 0.05-20 μg L(-1) for fipronil and flusilazole, with the correlation coefficients (r(2)) between 0.9966 and 0.9990. The method gave good precisions (relative standard deviation %) from 2.9 to 10.1% for real spiked samples from reservoir water and seawater; method recoveries ranged 92.2-105.9 and 98.5-103.9% for real spiked samples from reservoir water and seawater, respectively. Limits of detection (S/N = 3) for the method were determined to be 8-19 ng L(-1). The optimized method was successfully applied to the determination of four pesticides of pyrazoles and pyrroles in real environmental water samples.

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

    PubMed

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

    2015-05-15

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

  19. Determination of six sulfonylurea herbicides in environmental water samples by magnetic solid-phase extraction using multi-walled carbon nanotubes as adsorbents coupled with high-performance liquid chromatography.

    PubMed

    Ma, Jiping; Jiang, Lianhua; Wu, Gege; Xia, Yan; Lu, Wenhui; Li, Jinhua; Chen, Lingxin

    2016-09-30

    Magnetic solid-phase extraction (MSPE) using magnetic multi-walled carbon nanotubes (mag-MWCNTs) as adsorbents, coupled with high-performance liquid chromatography-diode-array detector (HPLC-DAD), was developed for the simultaneous separation and determination of six types of sulfonylurea herbicides (SUs) in environmental water samples. Several variables affecting MSPE efficiency were systematically investigated, including the type and volume of desorption solvent, sample solution pH, salt concentration, amount of mag-MWCNTs, and extraction and desorption time. Response surface was employed to assist in the MSPE optimization. Under optimized conditions, excellent linearity was achieved in the range of 0.05-5.0μg/L for all six SUs, with coefficients of correlation r>0.9994, and preconcentration factors ranging from 178 to 210. Limits of detection and quantification were 0.01-0.04μg/L and 0.03-0.13μg/L, respectively. The intra-day and inter-day precision (relative standard deviations, n=6, %) at three spiked levels were 2.0-11.0% and 2.1-12.9% in terms of peak area, respectively. The method recoveries at three fortified concentrations were obtained within 76.7-106.9% for reservoir water samples and 78.2-105.4% for tap water samples. The developed MSPE-HPLC method demonstrated high sensitivity, repeatability, simplicity, rapidity, and excellent practical applicability.

  20. Simultaneous determination of copper, cobalt, and mercury ions in water samples by solid-phase extraction using carbon nanotube sponges as adsorbent after chelating with sodium diethyldithiocarbamate prior to high performance liquid chromatography.

    PubMed

    Wang, Lei; Zhou, Jia-Bin; Wang, Xia; Wang, Zhen-Hua; Zhao, Ru-Song

    2016-06-01

    Recently, a sponge-like material called carbon nanotube sponges (CNT sponges) has drawn considerable attention because it can remove large-area oil, nanoparticles, and organic dyes from water. In this paper, the feasibility of CNT sponges as a novel solid-phase extraction (SPE) adsorbent for the enrichment and determination of heavy metal ions (Co(2+), Cu(2+), and Hg(2+)) was investigated for the first time. Sodium diethyldithiocarbamate (DDTC) was used as the chelating agent and high performance liquid chromatography (HPLC) for the final analysis. Important factors which may influence extraction efficiency of SPE were optimized, such as the kind and volume of eluent, volume of DDTC, sample pH, flow rate, etc. Under the optimized conditions, wide range of linearity (0.5-400 μg L(-1)), low limits of detection (0.089~0.690 μg L(-1); 0.018~0.138 μg), and good repeatability (1.27~3.60 %, n = 5) were obtained. The developed method was applied for the analysis of the three metal ions in real water samples, and satisfactory results were achieved. All of these findings demonstrated that CNT sponges will be a good choice for the enrichment and determination of target ions at trace levels in the future.

  1. Ultra high performance liquid chromatography with mass spectrometry method for the simultaneous determination of phenolic constituents in honey from various floral sources using multiwalled carbon nanotubes as extraction sorbents.

    PubMed

    Wabaidur, Saikh Mohammad; Ahmed, Yacine Badjah Hadj; Alothman, Zeid Abdullah; Obbed, Munir Saeed; AL-Harbi, Nasser Mohamed; AL-Turki, Turki Mohammad

    2015-08-01

    An ultra high performance liquid chromatography with mass spectrometry method has been developed for the simultaneous separation, identification and determination of 22 phenolic constituents in honey from various floral sources from Yemen. Solid-phase extraction was used for extraction of the target phenolic constituents from honey samples, while multiwalled carbon nanotubes were used as solid-phase adsorbent. The chromatographic separation of all phenolic constituents was performed on a BEH C18 column using a linear gradient elution with a binary mobile phase mixture of aqueous 0.1% formic acid and methanol. The quantitation was carried out in selected ion reaction monitoring acquisition mode. The total amount of phenolic acids, flavonoids and other phenols in each analyzed honey was found in the range of 338-3312, 122-5482 and 2.4-1342 μg/100 g of honey, respectively. 4-Hydroxybenzoic acid was found to be the major phenolic acid. The main detected flavonoid was chrysin, while cinnamic acid was found to be the major other phenol compound. The regeneration of solid phase adsorbent to be reused and recovery results confirm that the proposed method could be potentially used for the routine analysis of phenolic constituents in honey extract.

  2. [Determination of the trace residues of four organochlorine pesticides in agricultural products by high performance liquid chromatography with modified multi-walled carbon nanotubes as solid phase extraction adsorbent].

    PubMed

    Peng, Xiaojun; Pang, Jinshan; Deng, Aihua; Liang, Weihua; Liang, Youzhen; Wen, Qijing

    2012-09-01

    A novel method for the simultaneous determination of the trace residues of four organochlorine pesticides such as p,p'-DDD, p,p'-DDT, o,p'-DDT and p,p'-DDE in agricultural products by multi-walled carbon nanotubes (MWNTs) modified by acid oxidation on the surface as solid phase extraction (SPE) adsorbent coupled with high performance liquid chromatography (HPLC) was developed. The effects of the surface acid oxidation, SPE operations and HPLC conditions on the determination of the four pesticide residues were investigated. Under the optimized experimental conditions, the novel method provided wide linear ranges for the pesticides with correlation coefficients of 0. 997 8 - 0. 999 5, the detection limit was 0.050 mg/L for each pesticides. The recoveries from the samples spiked with the pesticide standards at three concentration levels of 0.10, 2.0 and 50 mg/L were in the range of 78% - 104% with the relative standard deviations (RSDs) of 2.7% -7.6%. This study indicated the MWNTs SPE was an efficient clean-up method to agricultural products (included dried orange peel, ginseng, cabbage and tea). The proposed method showed the advantages of accuracy and sensitivity, and can meet the requirements for the determination of low residue pesticide in agricultural products. The study provides a useful method for the analysis of trace substance of agricultural products.

  3. Inkjet Printing of Carbon Nanotubes

    PubMed Central

    Tortorich, Ryan P.; Choi, Jin-Woo

    2013-01-01

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

  4. Amino modified multi-walled carbon nanotubes/polydimethylsiloxane coated stir bar sorptive extraction coupled to high performance liquid chromatography-ultraviolet detection for the determination of phenols in environmental samples.

    PubMed

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

    2013-07-26

    In this work, amino modified multi-walled carbon nanotubes/polydimethylsiloxane (multi-walled carbon nanotubes-4,4'-diaminodiphenylmethane/polydimethylsiloxane, MWCNTs-DDM/PDMS) was synthesized, and utilized as a novel coating for stir bar sorptive extraction (SBSE) of seven phenols (phenol, 2-chlorophenol, 2-nitrophenol, 4-nitrophenol, 2,4-dimethylphenol, p-choro-m-cresol and 2,4,6-trichlorphenol) in environmental water and soil samples, followed by high performance liquid chromatography-ultraviolet detection (HPLC-UV). The prepared MWCNTs-DDM/PDMS coated stir bar was characterized and good preparation reproducibility was obtained with the relative standard deviations (RSDs) ranging from 4.7% to 11.3% (n=9) in one batch, and from 4.8% to 13.9% (n=8) among different batches. Several parameters affecting the extraction of seven target phenols by MWCNTs-DDM/PDMS-SBSE including extraction time, stirring rate, pH, ionic strength, desorption solvent and desorption time were investigated. Under the optimal experimental conditions, the limits of detection (LODs, S/N=3) were found to be in the range of 0.14μg/L (2-nitrophenol) to 1.76μg/L (phenol) and the limits of quantification (LOQs, S/N=10) were found to be in the range of 0.46μg/L (2-nitrophenol) to 5.8μg/L (phenol). The linear range was 5-1000μg/L for phenol and 4-nitrophenol, 1-1000μg/L for 2-nitrophenol and 2-1000μg/L for other phenols, respectively. The RSDs of the developed method were in the range of 6.2-11.6% (n=8, c=10μg/L) and the enrichment factors were from 6.5 to 62.8-fold (theoretical enrichment factor was 100-fold). The proposed method was successfully applied to the analysis of phenols in environmental water and soil samples, and good recoveries were obtained for the spiked samples. The proposed method is simple, highly sensitive and suitable for the analysis of trace phenols in environmental samples with complex matrix.

  5. From carbon nanostructures to high-performance sorbents for chromatographic separation and preconcentration

    NASA Astrophysics Data System (ADS)

    Postnov, V. N.; Rodinkov, O. V.; Moskvin, L. N.; Novikov, A. G.; Bugaichenko, A. S.; Krokhina, O. A.

    2016-02-01

    Information on carbon nanostructures (fullerenes, nanotubes, graphene, nanodiamond and nanodispersed active carbon) used to develop high-performance sorbents of organics and heavy metal ions from aqueous solutions is collected and analyzed. The advantages in the synthesis of hybrid carbon nanostructures and the possibilities of surface modification of these systems in order to carry out fast sorption pre-concentration are considered. Prospects for application of these materials in sorption technologies and analytical chemistry are discussed. The bibliography includes 364 references.

  6. Templated Growth of Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Siochik Emilie J. (Inventor)

    2007-01-01

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

  7. Carbon nanotube array based sensor

    DOEpatents

    Lee, Christopher L.; Noy, Aleksandr; Swierkowski, Stephan P.; Fisher, Karl A.; Woods, Bruce W.

    2005-09-20

    A sensor system comprising a first electrode with an array of carbon nanotubes and a second electrode. The first electrode with an array of carbon nanotubes and the second electrode are positioned to produce an air gap between the first electrode with an array of carbon nanotubes and the second electrode. A measuring device is provided for sensing changes in electrical capacitance between the first electrode with an array of carbon nanotubes and the second electrode.

  8. Purification of Carbon Nanotubes: Alternative Methods

    NASA Technical Reports Server (NTRS)

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

    2000-01-01

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

  9. Coated carbon nanotube array electrodes

    DOEpatents

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

    2008-10-28

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

  10. Coated carbon nanotube array electrodes

    DOEpatents

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

    2006-12-12

    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.

  11. Sorting Carbon Nanotubes.

    PubMed

    Zheng, Ming

    2017-02-01

    Sorting of single-wall carbon nanotubes by their electronic and atomic structures in liquid phases is reviewed in this chapter. We first introduce the sorting problem, and then provide an overview of several sorting methodologies, following roughly the chronological order of their development over the past 15 years or so. Major methods discussed include ion-exchange chromatography, density-gradient ultracentrifugation, selective extraction in organic solvents, gel chromatography, and aqueous two-phase extraction. A main focus of the review is on the common mechanisms underlining all sorting processes. We propose that differences in solvation among different nanotube species are the ultimate driving force of sorting, and we corroborate this proposal by presenting analysis on how the differences are realized in electronic-structure-based sorting and atomic-structure-based sorting. In the end, we offer some suggestions on future directions that may grow out of carbon nanotube sorting. In particular, the prospect of expanding the function of DNA/carbon nanotube hybrid to control inter-particle interactions both inside and outside the nanotube is discussed.

  12. Copper-philic carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Belgamwar, Sachin U.; Sharma, Niti Nipun

    2016-04-01

    Carbon nanotube is having poor wet-ability with copper metal. Wet-ability of carbon nanotube was improved by exposing and creating more active sites on the surface of carbon nanotube. Carbon nanotubes were subjected to the prolong ultrasonication treatment of 20×103 Hz and 500W, which helped in disentanglement of carbon nanotube agglomerates and in breaking the weak bonds like pentagonal or heptagonal structure on the surface and on the CNT cap. Disentanglement of the carbon nanotube, resulted in exposing the defective sites on the surface and breaking of weak bonds, which assisted in creating the new defects on the surface. This process results in generates more active sites on the surface and it helps in improving the wet-ability of the carbon nanotube in copper.

  13. Transport Through Carbon Nanotube Wires

    NASA Technical Reports Server (NTRS)

    Anantram, M. P.; Kwak, Dochan (Technical Monitor)

    2001-01-01

    This viewgraph presentation deals with the use of carbon nanotubes as a transport system. Contact, defects, tubular bend, phonons, and mechanical deformations all contribute to reflection within the nanotube wire. Bragg reflection, however, is native to an ideal energy transport system. Transmission resistance depends primarily on the level of energy present. Finally, the details regarding coupling between carbon nanotubes and simple metals are presented.

  14. Carbon nanotube filters

    NASA Astrophysics Data System (ADS)

    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.

  15. Carbon nanotube filters.

    PubMed

    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 ( approximately 25 nm) from water. These macro filters can be cleaned for repeated filtration through ultrasonication and autoclaving. The exceptional thermal and mechanical stability of nanotubes, and the high surface area, ease and cost-effective fabrication of the nanotube membranes may allow them to compete with ceramic- and polymer-based separation membranes used commercially.

  16. Carbon nanotubes for microelectronics?

    PubMed

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

    2005-04-01

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

  17. Toward High-Performance Hematite Nanotube Photoanodes: Charge-Transfer Engineering at Heterointerfaces.

    PubMed

    Kim, Do Hong; Andoshe, Dinsefa M; Shim, Young-Seok; Moon, Cheon-Woo; Sohn, Woonbae; Choi, Seokhoon; Kim, Taemin Ludvic; Lee, Migyoung; Park, Hoonkee; Hong, Kootak; Kwon, Ki Chang; Suh, Jun Min; Kim, Jin-Sang; Lee, Jong-Heun; Jang, Ho Won

    2016-09-14

    Vertically ordered hematite nanotubes are considered to be promising photoactive materials for high-performance water-splitting photoanodes. However, the synthesis of hematite nanotubes directly on conducting substrates such as fluorine-doped tin oxide (FTO)/glass is difficult to be achieved because of the poor adhesion between hematite nanotubes and FTO/glass. Here, we report the synthesis of hematite nanotubes directly on FTO/glass substrate and high-performance photoelectrochemical properties of the nanotubes with NiFe cocatalysts. The hematite nanotubes are synthesized by a simple electrochemical anodization method. The adhesion of the hematite nanotubes to the FTO/glass substrate is drastically improved by dipping them in nonpolar cyclohexane prior to postannealing. Bare hematite nanotubes show a photocurrent density of 1.3 mA/cm(2) at 1.23 V vs a reversible hydrogen electrode, while hematite nanotubes with electrodeposited NiFe cocatalysts exhibit 2.1 mA/cm(2) at 1.23 V which is the highest photocurrent density reported for hematite nanotubes-based photoanodes for solar water splitting. Our work provides an efficient platform to obtain high-performance water-splitting photoanodes utilizing earth-abundant hematite and noble-metal-free cocatalysts.

  18. The Toxicology of Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

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

    2012-06-01

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

  19. Carbon Nanotube Purification and Functionalization

    NASA Technical Reports Server (NTRS)

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

    2003-01-01

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

  20. Production of carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Journet, C.; Bernier, P.

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

  1. Carbon nanotubes on a substrate

    DOEpatents

    Gao, Yufei [Kennewick, WA; Liu, Jun [West Richland, WA

    2002-03-26

    The present invention includes carbon nanotubes whose hollow cores are 100% filled with conductive filler. The carbon nanotubes are in uniform arrays on a conductive substrate and are well-aligned and can be densely packed. The uniformity of the carbon nanotube arrays is indicated by the uniform length and diameter of the carbon nanotubes, both which vary from nanotube to nanotube on a given array by no more than about 5%. The alignment of the carbon nanotubes is indicated by the perpendicular growth of the nanotubes from the substrates which is achieved in part by the simultaneous growth of the conductive filler within the hollow core of the nanotube and the densely packed growth of the nanotubes. The present invention provides a densely packed carbon nanotube growth where each nanotube is in contact with at least one nearest-neighbor nanotube. The substrate is a conductive substrate coated with a growth catalyst, and the conductive filler can be single crystals of carbide formed by a solid state reaction between the substrate material and the growth catalyst. The present invention further provides a method for making the filled carbon nanotubes on the conductive substrates. The method includes the steps of depositing a growth catalyst onto the conductive substrate as a prepared substrate, creating a vacuum within a vessel which contains the prepared substrate, flowing H2/inert (e.g. Ar) gas within the vessel to increase and maintain the pressure within the vessel, increasing the temperature of the prepared substrate, and changing the H2/Ar gas to ethylene gas such that the ethylene gas flows within the vessel. Additionally, varying the density and separation of the catalyst particles on the conductive substrate can be used to control the diameter of the nanotubes.

  2. Method of manufacturing carbon nanotubes

    NASA Technical Reports Server (NTRS)

    Benavides, Jeanette M. (Inventor); Leidecker, Henning W. (Inventor); Frazier, Jeffrey (Inventor)

    2004-01-01

    A process for manufacturing carbon nanotubes, including a step of inducing electrical current through a carbon anode and a carbon cathode under conditions effective to produce the carbon nanotubes, wherein the carbon cathode is larger than the carbon anode. Preferably, a welder is used to induce the electrical current via an arc welding process. Preferably, an exhaust hood is placed on the anode, and the process does not require a closed or pressurized chamber. The process provides high-quality, single-walled carbon nanotubes, while eliminating the need for a metal catalyst.

  3. Carbon nanotube network varactor

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

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

  4. Carbon Nanotubes Toxicity

    NASA Astrophysics Data System (ADS)

    Bellucci, Stefano

    We describe current and possible future developments in nanotechnology for biological and medical applications. Nanostructured, composite materials for drug delivery, biosensors, diagnostics and tumor therapy are reviewed as examples, placing special emphasis on silica composites. Carbon nanotubes are discussed as a primary example of emerging nanomaterials for many of the above-mentioned applications. Toxicity effects of this novel nanomaterial are discussed and the need for further study of potential hazards for human health, professionally exposed workers and the environment is motivated.

  5. Carbon nanotube IR detectors (SV)

    SciTech Connect

    Leonard, F. L.

    2012-03-01

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

  6. Carbon Nanotubes Based Quantum Devices

    NASA Technical Reports Server (NTRS)

    Lu, Jian-Ping

    1999-01-01

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

  7. Optoelectronics with Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Kinoshita, Megumi

    2011-12-01

    The carbon nanotube is a promising material for future micro- and nano-scale electronics because of its unique electronic properties, high carrier mobility and extraordinary capacity for high current density. In particular, semiconducting carbon nanotubes are direct bandgap materials with a typical energy gap in the order of 1 eV, which means they emit light in the near-infrared range, making them an attractive option in telecommunications applications. However, there have been few systematic investigations of electrically-induced light emission (i.e. electroluminescence) from carbon nanotubes, and their emission properties are not well understood. In this dissertation, we explore the characteristics of electroluminescence in three different types of carbon-nanotube devices. The first is a single-tube field-effect transistor (CNTFET), whose emission has previously been found to have a very broad spectral shape and low emission efficiency. We analyze the spectral shape in detail, which reveals that a high electric field near metal contacts contributes most to the bias-dependent component of broadening, in addition to smaller contributions from tube nonuniformity, inelastic scattering of phonons, high temperature, etc. In the second part of the study, single-tube light-emitting diodes are constructed by employing a split top-gate scheme. The split gate creates p- and n-doped regions electrostatically, so that electrons and holes combine between the two sections and can decay radiatively. This configuration creates electron-hole pairs under much lower electric fields and gives us a greater control over carrier distribution in the device channel, resulting in much narrower spectral linewidths and an emission intensity several orders of magnitude larger than that of CNTFETs. The much better signal-to-noise also leads to the observation of emission from defect-induced states. Finally, we extend the idea of the single-tube p-n diode and fabricate CNT film diodes from many

  8. Carbon nanotube Archimedes screws.

    PubMed

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

    2010-12-28

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

  9. Carbon nanotubes: opportunities and challenges

    NASA Astrophysics Data System (ADS)

    Dai, Hongjie

    2002-03-01

    Carbon nanotubes are graphene sheets rolled-up into cylinders with diameters as small as one nanometer. Extensive work carried out worldwide in recent years has revealed the intriguing electrical and mechanical properties of these novel molecular scale wires. It is now well established that carbon nanotubes are ideal model systems for studying the physics in one-dimensional solids and have significant potential as building blocks for various practical nanoscale devices. Nanotubes have been shown to be useful for miniaturized electronic, mechanical, electromechanical, chemical and scanning probe devices and materials for macroscopic composites. Progress in nanotube growth has facilitated the fundamental study and applications of nanotubes. Gaining control over challenging nanotube growth issues is critical to the future advancement of nanotube science and technology, and is being actively pursued by researchers.

  10. Half-metallic carbon nanotubes.

    PubMed

    Lee, Kyu Won; Lee, Cheol Eui

    2012-04-17

    Half-metallicity in carbon nanotubes is achieved and controlled by hydrogen adsorption patterns. The edge states in carbon nanotubes are unstable under an electric field due to the spin-conserving electron transfer between the edges, but a large enough transfer barrier between the edge states, obtained by controlling the adsorption patterns, renders the CNTs half-metallic.

  11. Carbon Nanotube Based Flexible Supercapacitors

    DTIC Science & Technology

    2011-04-01

    NOTES 14. ABSTRACT Electrochemical double layer capacitors are fabricated using carbon nanotube (CNT)/paper flexible electrodes. An extensive...TERMS Carbon nanotube, supercapacitor, electrochemical double layer capacitor 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT UU 18...layer capacitors (Supercapacitors) are expected to play a significant role in future hybrid power systems due to their high specific power, cycle

  12. Carbon nanotubes as liquid crystals.

    PubMed

    Zhang, Shanju; Kumar, Satish

    2008-09-01

    Carbon nanotubes are the best of known materials with a combination of excellent mechanical, electronic, and thermal properties. To fully exploit individual nanotube properties for various applications, the grand challenge is to fabricate macroscopic ordered nanotube assemblies. Liquid-crystalline behavior of the nanotubes provides a unique opportunity toward reaching this challenge. In this Review, the recent developments in this area are critically reviewed by discussing the strategies for fabricating liquid-crystalline phases, addressing the solution properties of liquid-crystalline suspensions, and exploiting the practical techniques of liquid-crystal routes to prepare macroscopic nanotube fibers and films.

  13. Carbon nanotube sensors

    NASA Astrophysics Data System (ADS)

    Dai, Liming

    2002-07-01

    Measurement represents one of the oldest methods used by human beings to better understand and control the world. Many measurement systems are primarily physical sensors, which measure time, temperature, weight, distance, and various other physical parameters. The need for cheaper, faster, and more accurate meansurements has been a driving force for the development of new systems and technologies for measurements of materials, both chemical and biological. In fact, chemical and biological sensors (or biosensors) are the evolved products of physical measurement technologies. Chemical sensors are measurement devices that convert a chemical or physical change of a specific analyte into a measurable signal, whose magnitude is normally proportional to the concentration of the analyte. On the other hand, biosensors are a subset of chemical sensors that employ a biological sensing element connected to a transducer to recognize the physiochemical change and to produce the measurable signal from particular analytes, which are not necessary to be biological materials themselves, although sometimes they are. Depending on the basis of the transduction principle, chemical and biological sensors can be classified into three major classes with different transducers: sensors with electrical transducers, sensors with optical transducers, and sensors with other transducers (e.g. mass change). The unique properties of carbon nanotubes have led to their use in areas as diverse as sensors, actuators, field-emitting flat panel displays, energy and gas storages (Dai and Mau, 2001). As we shall see below, the principles for carbon nanotube sensors to detect the nature of gases and to determine their concentrations are based on change in electrical properties induced by charge transfer with the gas molecules (e.g. O2, H2, CO2) or in mass due to physical adsorption. This article provides a status report on the research and development of carbon nanotube sensors.

  14. Studies of Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Caneba, Gerard T.

    2005-01-01

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

  15. Using multi-walled carbon nanotubes as solid phase extraction adsorbents to determine dichlorodiphenyltrichloroethane and its metabolites at trace level in water samples by high performance liquid chromatography with UV detection.

    PubMed

    Zhou, Qingxiang; Xiao, Junping; Wang, Weidong

    2006-09-01

    Carbon nanotubes (CNTs) are a kind of new carbon-based nano-materials which have drawn great attention in many application fields. The potential of multi-walled carbon nanotubes (MWNTs) as solid-phase extraction (SPE) adsorbents for the preconcentration of environmental pollutants has been investigated in recent years. The goal of this work was to investigate the feasibility of MWNTs used as SPE adsorbents to enrich dichlorodiphenyltrichloroethane (DDT) and its metabolites including 1,1-dichloro-2,2-bis-(4'-chlorophenyl)ethane (DDD) and 1,1-dichloro-2,2-bis-(4'-chlorophenyl)ethane (DDE) at trace level which are typical persistent organic pollutants in environment. Parameters that maybe influence the extraction efficiency such as the eluent volume, sample flow rate, sample pH and the sample volume were optimized in detail. The experimental results showed the excellent linear relationship between peak area and the concentration of DDT and its metabolites over the range of 0.2-60 microg L(-1), and the precisions (RSD) were 2.3-2.5% under the optimal conditions. The detection limits of proposed method could reach 4-13 ng L(-1) based on the ratio of chromatographic signal to base line noise (S/N = 3). Satisfied results were achieved when the proposed method was applied to determine the four target compounds in realworld water samples with spiked recoveries over the range of 89.7-115.5%. All these facts indicated that MWCNTs as SPE packing materials coupled to HPLC was an excellent alternative for the routine analysis of DDT and its metabolites at trace level in environment.

  16. Functionalization of Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

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

    2007-01-01

    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 particles, such as atomic H or F, in a first chamber. The target particles are directed 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 particles, at or below room temperature, to a point of saturation, in an exposure time interval no longer than about 30 sec.

  17. Functionalization of carbon nanotubes

    NASA Technical Reports Server (NTRS)

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

    2007-01-01

    Method and system for functionalizing a collection of carbon nanotubes (CNTs). A selected precursor gas (e.g., H.sub.2 or F.sub.2 or C.sub.nH.sub.m) is irradiated to provide a cold plasma of selected target particles, such as atomic H or F, in a first chamber. The target particles are directed 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 particles, at or below room temperature, to a point of saturation, in an exposure time interval no longer than about 30 sec.

  18. Carbon Nanotube Interconnect

    NASA Technical Reports Server (NTRS)

    Li, Jun (Inventor); Meyyappan, Meyya (Inventor)

    2006-01-01

    Method and system for fabricating an electrical interconnect capable of supporting very high current densities ( 10(exp 6)-10(exp 10) Amps/sq cm), using an array of one or more carbon nanotubes (CNTs). The CNT array is grown in a selected spaced apart pattern, preferably with multi-wall CNTs, and a selected insulating material, such as SiOw, or SiuNv is deposited using CVD to encapsulate each CNT in the array. An exposed surface of the insulating material is planarized to provide one or more exposed electrical contacts for one or more CNTs.

  19. Carbon Nanotubes for Space Applications

    NASA Technical Reports Server (NTRS)

    Meyyappan, Meyya

    2000-01-01

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

  20. Continuous carbon nanotube reinforced composites.

    PubMed

    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.

  1. High Performance Organic Transistors: Percolating Arrays of Nanotubes Functionalized with an Electron Deficient Olefin

    DTIC Science & Technology

    2011-04-03

    electronics. In the present work, we have extended carbon nanotube functionalization via a 2-2 cycloaddition to electron withdrawing non-fluorinated...have extended carbon nanotube functionalization via a 2-2 cycloaddition to electron withdrawing non-fluorinated olefins as well. Our results show...Moyon et Al. 27 work on cycloaddition of azomenthine suggests preferential functionalization of the semiconducting tubes. In contrast, Kamaras et al

  2. Carbon Nanotube Biosensors

    NASA Astrophysics Data System (ADS)

    Tilmaciu, Carmen-Mihaela; Morris, May

    2015-10-01

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

  3. Carbon nanotube biosensors

    PubMed Central

    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

  4. Atomic transportation via carbon nanotubes.

    PubMed

    Wang, Quan

    2009-01-01

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

  5. Method for synthesizing carbon nanotubes

    DOEpatents

    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.

  6. Carbon nanotubes in hyperthermia therapy.

    PubMed

    Singh, Ravi; Torti, Suzy V

    2013-12-01

    Thermal tumor ablation therapies are being developed with a variety of nanomaterials, including single- and multiwalled carbon nanotubes. Carbon nanotubes (CNTs) have attracted interest due to their potential for simultaneous imaging and therapy. In this review, we highlight in vivo applications of carbon nanotube-mediated thermal therapy (CNMTT) and examine the rationale for use of this treatment in recurrent tumors or those resistant to conventional cancer therapies. Additionally, we discuss strategies to localize and enhance the cancer selectivity of this treatment and briefly examine issues relating the toxicity and long term fate of CNTs.

  7. Carbon nanotubes as vaccine scaffolds

    PubMed Central

    Scheinberg, David A.; McDevitt, Michael R.; Dao, Tao; Mulvey, Justin J.; Feinberg, Evan; Alidori, Simone

    2013-01-01

    Carbon nanotubes display characteristics that are potentially useful in their development as scaffolds for vaccine compositions. These features include stability in vivo, lack of intrinsic immunogenicity, low toxicity, and the ability to be appended with multiple copies of antigens. In addition, the particulate nature of carbon nanotubes and their unusual properties of rapid entry into antigen-presenting cells, such as dendritic cells, make them especially useful as carriers of antigens. Early attempts demonstrating carbon nanotube-based vaccines can be used in both infectious disease settings and cancer are promising. PMID:23899863

  8. Carbon nanotubes in hyperthermia therapy

    PubMed Central

    Singh, Ravi; Torti, Suzy V.

    2013-01-01

    Thermal tumor ablation therapies are being developed with a variety of nanomaterials, including single-and multiwalled carbon nanotubes. Carbon nanotubes (CNTs) have attracted interest due to their potential for simultaneous imaging and therapy. In this review, we highlight in vivo applications of carbon nanotube-mediated thermal therapy (CNMTT) and examine the rationale for use of this treatment in recurrent tumors or those resistant to conventional cancer therapies. Additionally, we discuss strategies to localize and enhance the cancer selectivity of this treatment and briefly examine issues relating the toxicity and long term fate of CNTs. PMID:23933617

  9. Carbon nanotubes: engineering biomedical applications.

    PubMed

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

    2011-01-01

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

  10. Method for producing carbon nanotubes

    DOEpatents

    Phillips, Jonathan; Perry, William L.; Chen, Chun-Ku

    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.

  11. High performance enzyme fuel cells using a genetically expressed FAD-dependent glucose dehydrogenase α-subunit of Burkholderia cepacia immobilized in a carbon nanotube electrode for low glucose conditions.

    PubMed

    Fapyane, Deby; Lee, Soo-Jin; Kang, Seo-Hee; Lim, Du-Hyun; Cho, Kwon-Koo; Nam, Tae-hyun; Ahn, Jae-Pyoung; Ahn, Jou-Hyeon; Kim, Seon-Won; Chang, In Seop

    2013-06-28

    FAD-dependent glucose dehydrogenase (FAD-GDH) of Burkholderia cepacia was successfully expressed in Escherichia coli and subsequently purified in order to use it as an anode catalyst for enzyme fuel cells. The purified enzyme has a low Km value (high affinity) towards glucose, which is 463.8 μM, up to 2-fold exponential range lower compared to glucose oxidase. The heterogeneous electron transfer coefficient (Ks) of FAD-GDH-menadione on a glassy carbon electrode was 10.73 s(-1), which is 3-fold higher than that of GOX-menadione, 3.68 s(-1). FAD-GDH was able to maintain its native glucose affinity during immobilization in the carbon nanotube and operation of enzyme fuel cells. FAD-GDH-menadione showed 3-fold higher power density, 799.4 ± 51.44 μW cm(-2), than the GOX-menadione system, 308.03 ± 17.93 μW cm(-2), under low glucose concentration, 5 mM, which is the concentration in normal physiological fluid.

  12. Composite of Cu metal nanoparticles-multiwall carbon nanotubes-reduced graphene oxide as a novel and high performance platform of the electrochemical sensor for simultaneous determination of nitrite and nitrate.

    PubMed

    Bagheri, Hasan; Hajian, Ali; Rezaei, Mosayeb; Shirzadmehr, Ali

    2017-02-15

    In the present research, we aimed to fabricate a novel electrochemical sensor based on Cu metal nanoparticles on the multiwall carbon nanotubes-reduced graphene oxide nanosheets (Cu/MWCNT/RGO) for individual and simultaneous determination of nitrite and nitrate ions. The morphology of the prepared nanocomposite on the surface of glassy carbon electrode (GCE) was characterized using various methods including scanning electron microscopy (SEM), atomic force microscopy (AFM), and electrochemical impedance spectroscopy. Under optimal experimental conditions, the modified GCE showed excellent catalytic activity toward the electro-reduction of nitrite and nitrate ions (pH=3.0) with a significant increase in cathodic peak currents in comparison with the unmodified GCE. By square wave voltammetry (SWV) the fabricated sensor demonstrated wide dynamic concentration ranges from 0.1 to 75μM with detection limits (3Sb/m) of 30nM and 20nM method for nitrite and nitrate ions, respectively. Furthermore, the applicability of the proposed modified electrode was demonstrated by measuring the concentration of nitrite and nitrate ions in the tap and mineral waters, sausages, salami, and cheese samples.

  13. Optimizing the thermoelectric performance of zigzag and chiral carbon nanotubes

    PubMed Central

    2012-01-01

    Using nonequilibrium molecular dynamics simulations and nonequilibrium Green's function method, we investigate the thermoelectric properties of a series of zigzag and chiral carbon nanotubes which exhibit interesting diameter and chirality dependence. Our calculated results indicate that these carbon nanotubes could have higher ZT values at appropriate carrier concentration and operating temperature. Moreover, their thermoelectric performance can be significantly enhanced via isotope substitution, isoelectronic impurities, and hydrogen adsorption. It is thus reasonable to expect that carbon nanotubes may be promising candidates for high-performance thermoelectric materials. PMID:22325623

  14. Carbon nanotube electron gun

    NASA Technical Reports Server (NTRS)

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

    2010-01-01

    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.

  15. Carbon Nanotube Electron Gun

    NASA Technical Reports Server (NTRS)

    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.

  16. Toxicity of carbon nanotubes.

    PubMed

    Wang, Jing; Xu, Yuanzhi; Yang, Zhi; Huang, Renhuan; Chen, Jing; Wang, Raorao; Lin, Yunfeng

    2013-10-01

    Carbon nanotubes (CNTs) find their extensive application as a promising material in medicine due to unique characteristics. However, such materials have been accompanied with potentially hazardous effects on human health. The toxicity of CNTs may vary depending on their structural characteristics, surface properties and chemical composition. To gain insight into the toxicity of CNTs in vivo and in vitro, we summarize contributing factors for the toxic effects of CNTs in this review. In addition, we elaborate on the toxic effects and mechanisms in target sites at systemic, organic, cellular, and biomacromolecule levels. Various issues are reported to be effected when exposed to CNTs including (1) blood circulation, (2) lymph circulation, (3) lung, (4) heart, (5) kidney, (6) spleen, (7) bone marrow, and (8) blood brain barrier. Though there have been published reports on the toxic effects of CNTs to date, more studies will still be needed to gain full understanding of their potential toxicity and underlying mechanisms.

  17. Carbon nanotube biconvex microcavities

    SciTech Connect

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

    2015-03-23

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

  18. Functionalization of Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    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.

  19. Carbon Nanotube based Nanotechnolgy

    NASA Astrophysics Data System (ADS)

    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.

  20. Selective functionalization of carbon nanotubes

    NASA Technical Reports Server (NTRS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  2. Nanotechnology with Carbon Nanotubes: Mechanics, Chemistry, and Electronics

    NASA Technical Reports Server (NTRS)

    Srivastava, Deepak

    2003-01-01

    This viewgraph presentation reviews the Nanotechnology of carbon nanotubes. The contents include: 1) Nanomechanics examples; 2) Experimental validation of nanotubes in composites; 3) Anisotropic plastic collapse; 4) Spatio-temporal scales, yielding single-wall nanotubes; 5) Side-wall functionalization of nanotubes; 6) multi-wall Y junction carbon nanotubes; 7) Molecular electronics with Nanotube junctions; 8) Single-wall carbon nanotube junctions; welding; 9) biomimetic dendritic neurons: Carbon nanotube, nanotube electronics (basics), and nanotube junctions for Devices,

  3. Filling carbon nanotubes with particles.

    PubMed

    Kim, Byong M; Qian, Shizhi; Bau, Haim H

    2005-05-01

    The filling of carbon nanotubes (CNTs) with fluorescent particles was studied experimentally and theoretically. The fluorescent signals emitted by the particles were visible through the walls of the nanotubes, and the particles inside the tubes were observable with an electron microscope. Taking advantage of the template-grown carbon nanotubes' transparency to fluorescent light, we measured the filling rate of the tubes with particles at room conditions. Liquids such as ethylene glycol, water, and ethylene glycol/water mixtures, laden with 50 nm diameter fluorescent particles, were brought into contact with 500 nm diameter CNTs. The liquid and the particles' transport were observed, respectively, with optical and fluorescence microscopy. The CNTs were filled controllably with particles by the complementary action of capillary forces and the evaporation of the liquid. The experimental results were compared and favorably agreed with theoretical predictions. This is the first report on fluorescence studies of particle transport in carbon nanotubes.

  4. Properties of Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

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

    2012-10-01

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

  5. Carbon Nanotube Purification

    NASA Technical Reports Server (NTRS)

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

    2005-01-01

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

  6. Carbon Nanotubes for Polymer Photovoltaics

    NASA Astrophysics Data System (ADS)

    Anctil, Annick; Dileo, Roberta; Schauerman, Chris; Landi, Brian; Raffaelle, Ryne

    2007-03-01

    Carbon nanotubes are being investigated for optical absorption, exciton dissociation, and carrier transport in polymer photovoltaic devices. In the present work, single wall carbon nanotubes (SWNTs) were synthesized by an Alexandrite pulsed laser vaporization reactor at standard conditions and purified based upon our previously reported TOP procedure. The SWNTs were dispersed in polymer composites for pure MEH-PPV, pure P3HT, and [C60]-PCBM-P3HT (1:1 by weight) as a function of nanotube weight loading (0.1 -- 5% w/w). The AM0 current-voltage measurements for structures sandwiched between PEDOT/PSS coated ITO substrates and an evaporated aluminum contact demonstrate the dramatic effect of SWNT content on the short circuit current density, with conversions efficiencies consistently greater than 1%. The temperature coefficient for nanotube-containing polymer photovoltaics has been compared to conventional PCBM-P3HT devices, and the general relationship of increasing efficiency with increasing temperature is observed. However, the necessity to control nanotube percolation to prevent device shunting has led to recent developments which focus on controlling nanotube length through oxidative cutting, the deposition of intrinsic polymer layers, and the use of aligned carbon nanotube arrays for preferential charge transport.

  7. Printed Carbon Nanotube Electronics and Sensor Systems.

    PubMed

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

    2016-06-01

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

  8. Probing Photosensitization by Functionalized Carbon Nanotubes

    EPA Science Inventory

    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 ...

  9. Occupational Exposure to Carbon Nanotubes and Nanofibers

    MedlinePlus

    ... Current Intelligence Bulletin 65: Occupational Exposure to Carbon Nanotubes and Nanofibers Recommend on Facebook Tweet Share Compartir ... composed of engineered nanoparticles, such as metal oxides, nanotubes, nanowires, quantum dots, and carbon fullerenes (buckyballs), among ...

  10. Carbon Nanotube Based Molecular Electronics

    NASA Technical Reports Server (NTRS)

    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.

  11. Multiscale Modeling with Carbon Nanotubes

    SciTech Connect

    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.

  12. Removal of some impurities from carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Feng, Yongcheng; Zhou, Gumin; Wang, Guoping; Qu, Meizhen; Yu, Zuolong

    2003-07-01

    A non-destructive mild oxidation method of removing some impurities from as-grown carbon nanotubes (CNTs), including single-wall carbon nanotubes (SWNTs) and multi-wall carbon nanotubes (MWNTs), by H 2O 2 oxidation and HCl treatment, has been investigated, and somewhat pure carbon nanotubes have been prepared. The CNTs from which some impurities were removed have been evaluated by transmission electron microscopy (TEM) and temperature programmed oxidation and gas chromatography (TPO-GC).

  13. EDITORIAL: Focus on Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    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 <;A article="1367-2630/5/1/117">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

  14. EDITORIAL: Focus on Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    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

  15. Large-Scale Processing of Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Finn, John; Sridhar, K. R.; Meyyappan, M.; Arnold, James O. (Technical Monitor)

    1998-01-01

    Scale-up difficulties and high energy costs are two of the more important factors that limit the availability of various types of nanotube carbon. While several approaches are known for producing nanotube carbon, the high-powered reactors typically produce nanotubes at rates measured in only grams per hour and operate at temperatures in excess of 1000 C. These scale-up and energy challenges must be overcome before nanotube carbon can become practical for high-consumption structural and mechanical applications. This presentation examines the issues associated with using various nanotube production methods at larger scales, and discusses research being performed at NASA Ames Research Center on carbon nanotube reactor technology.

  16. Dispersions of Carbon nanotubes in Polymer Matrices

    NASA Technical Reports Server (NTRS)

    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.

  17. Hydrodynamic properties of carbon nanotubes.

    PubMed

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

    2004-06-01

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

  18. Single-walled carbon nanotube buckypaper and mesophase pitch carbon/carbon composites

    NASA Astrophysics Data System (ADS)

    Park, Jin Gyu; Yun, Nam Gyun; Park, Young Bin; Liang, Richard; Lumata, Lloyd; Brooks, James; Zhang, Chuck; Wang, Ben; High-Performance Materials Institute, Fsu Collaboration; National High Magnetic Field Laboratory, Fsu Collaboration

    2011-03-01

    Carbon/carbon composites consisting of single-walled carbon nanotube (SWCNT) buckypaper (BP) and mesophase pitch resin have been produced through impregnation of BP with pitch using toluene as a solvent. Drying, stabilization and carbonization processes were performed sequentially, and repeated to increase the pitch content. Voids in the carbon/carbon composite samples decreased with increasing impregnation process cycles. Electrical conductivity and density of the composites increased with carbonization by two to three times that of pristine BP. These results indicate that discontinuity and intertube contact barriers of SWCNTs in the BP are partially overcome by the carbonization process of pitch. The temperature dependence of the Raman shift shows that mechanical strain is increased since carbonized pitch matrix surrounds the nanotubes. High-Performance Materials Institute, NSF DMR-0602859, NSF DMR-0654118.

  19. Carbon nanotube-polymer composite actuators

    DOEpatents

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

    2008-04-22

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

  20. Carbon nanotubes for ultrafast fibre lasers

    NASA Astrophysics Data System (ADS)

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

    2017-01-01

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

  1. Carbon nanotubes for ultrafast fibre lasers

    NASA Astrophysics Data System (ADS)

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

    2016-06-01

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

  2. Gears Based on Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Jaffe, Richard; Han, Jie; Globus, Al; Deardorff, Glenn

    2005-01-01

    Gears based on carbon nanotubes (see figure) have been proposed as components of an emerging generation of molecular- scale machines and sensors. In comparison with previously proposed nanogears based on diamondoid and fullerene molecules, the nanotube-based gears would have simpler structures and are more likely to be realizable by practical fabrication processes. The impetus for the practical development of carbon-nanotube- based gears arises, in part, from rapid recent progress in the fabrication of carbon nanotubes with prescribed diameters, lengths, chiralities, and numbers of concentric shells. The shafts of the proposed gears would be made from multiwalled carbon nanotubes. The gear teeth would be rigid molecules (typically, benzyne molecules), bonded to the nanotube shafts at atomically precise positions. For fabrication, it may be possible to position the molecular teeth by use of scanning tunneling microscopy (STM) or other related techniques. The capability to position individual organic molecules at room temperature by use of an STM tip has already been demonstrated. Routes to the chemical synthesis of carbon-nanotube-based gears are also under investigation. Chemical and physical aspects of the synthesis of molecular scale gears based on carbon nanotubes and related molecules, and dynamical properties of nanotube- based gears, have been investigated by computational simulations using established methods of quantum chemistry and molecular dynamics. Several particularly interesting and useful conclusions have been drawn from the dynamical simulations performed thus far: The forces acting on the gears would be more sensitive to local molecular motions than to gross mechanical motions of the overall gears. Although no breakage of teeth or of chemical bonds is expected at temperatures up to at least 3,000 K, the gears would not work well at temperatures above a critical range from about 600 to about 1,000 K. Gear temperature could probably be controlled by

  3. CMOS Integrated Carbon Nanotube Sensor

    SciTech Connect

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

    2009-05-23

    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.

  4. Magnetoresistance of multiwall carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Lu, Li; Kang, N.; Kong, W. J.; Hu, J. S.; Pan, Z. W.; Xie, S. S.

    2002-03-01

    We have investigated the magnetoresistance of multiwall carbon nanotubes bundles. At temperatures above 15 K, the magnetoresistance was found to follow exactly a scaling law as predicted by the theory of two-dimensional (2D) weak localization. Below 15 K, the 2D weak localization behavior is modified due to the formation of a Coulomb gap. This modification does not fit to those theories which treat electron-electron interaction as a perturbation. Altshular-Aronov-Spivak (AAS) resistance oscillation was observed in milli-Kelvin temperature range. The results will be discussed in terms of the interplay between electron-electron interaction and disorder scattering in multiwall carbon nanotube.

  5. Modified carbon nanotubes and methods of forming carbon nanotubes

    DOEpatents

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

    2016-06-14

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

  6. Effect of Carbon Nanotubes on Mammalian Cells

    NASA Astrophysics Data System (ADS)

    Chen, Michelle; Ahmed, Asma; Black, Melanie; Kawamoto, Nicole; Lucas, Jessica; Pagala, Armie; Pham, Tram; Stankiewicz, Sara; Chen, Howard

    2010-03-01

    Carbon Nanotubes possess extraordinary electrical, mechanical, and thermal properties. Research on applying the carbon nanotubes for ultrasensitive detection, disease diagnosis, and drug delivery is rapidly developing. While the fundamental and technological findings on carbon nanotubes show great promise, it is extremely important to investigate the effect of the carbon nanotubes on human health. In our experiments, we introduce purified carbon nanotubes in suspension to ovary cells cultured from Hamsters. These cells are chosen since they show robust morphological changes associated with cytotoxicity that can easily be observed under a light microscope. We will discuss the toxicity of carbon nanotubes by characterizing the cell morphology and viability as a function of time and the concentration of carbon nanotube suspension.

  7. Carbon Nanotube Material Quality Assessment

    NASA Technical Reports Server (NTRS)

    Yowell, Leonard; Arepalli, Sivaram; Sosa, Edward; Niolaev, Pavel; Gorelik, Olga

    2006-01-01

    The nanomaterial activities at NASA Johnson Space Center focus on carbon nanotube production, characterization and their applications for aerospace systems. Single wall carbon nanotubes are produced by arc and laser methods. Characterization of the nanotube material is performed using the NASA JSC protocol developed by combining analytical techniques of SEM, TEM, UV-VIS-NIR absorption, Raman, and TGA. A possible addition of other techniques such as XPS, and ICP to the existing protocol will be discussed. Changes in the quality of the material collected in different regions of the arc and laser production chambers is assessed using the original JSC protocol. The observed variations indicate different growth conditions in different regions of the production chambers.

  8. Carbon nanotube electronics--moving forward.

    PubMed

    Wang, Chuan; Takei, Kuniharu; Takahashi, Toshitake; Javey, Ali

    2013-04-07

    Single-walled carbon nanotubes (SWNTs) possess fascinating electrical properties and offer new entries into a wide range of novel electronic applications that are unattainable with conventional Si-based devices. The field initially focused on the use of individual or parallel arrays of nanotubes as the channel material for ultra-scaled nanoelectronic devices. However, the challenge in the deterministic assembly has proven to be a major technological barrier. In recent years, solution deposition of semiconductor-enriched SWNT networks has been actively explored for high performance and uniform thin-film transistors (TFTs) on mechanically rigid and flexible substrates. This presents a unique niche for nanotube electronics by overcoming their limitations and taking full advantage of their superb chemical and physical properties. This review focuses on the large-area processing and electronic properties of SWNT TFTs. A wide range of applications in conformal integrated circuits, radio-frequency electronics, artificial skin sensors, and displays are discussed--with emphasis on large-area systems where nm-scale accuracy in the assembly of nanotubes is not required. The demonstrations show SWNTs' immense promise as a low-cost and scalable TFT technology for nonconventional electronic systems with excellent device performances.

  9. Conductance Oscillations in Squashed Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Mehrez, H.; Anantram, M. P.; Svizhenko, A.

    2003-01-01

    A combination of molecular dynamics and electrical conductance calculations are used to probe the electromechanical properties of squashed metallic carbon nanotubes. We find that the conductance and bandgap of armchair nanotubes show oscillations upon squashing. The physical origin of these oscillations is attributed to interaction of carbon atoms with a fourth neighbor. Squashing of armchair and zigzag nanotubes ultimately leads to metallic behavior.

  10. Supported lipid bilayer/carbon nanotube hybrids

    NASA Astrophysics Data System (ADS)

    Zhou, Xinjian; Moran-Mirabal, Jose M.; Craighead, Harold G.; McEuen, Paul L.

    2007-03-01

    Carbon nanotube transistors combine molecular-scale dimensions with excellent electronic properties, offering unique opportunities for chemical and biological sensing. Here, we form supported lipid bilayers over single-walled carbon nanotube transistors. We first study the physical properties of the nanotube/supported lipid bilayer structure using fluorescence techniques. Whereas lipid molecules can diffuse freely across the nanotube, a membrane-bound protein (tetanus toxin) sees the nanotube as a barrier. Moreover, the size of the barrier depends on the diameter of the nanotube-with larger nanotubes presenting bigger obstacles to diffusion. We then demonstrate detection of protein binding (streptavidin) to the supported lipid bilayer using the nanotube transistor as a charge sensor. This system can be used as a platform to examine the interactions of single molecules with carbon nanotubes and has many potential applications for the study of molecular recognition and other biological processes occurring at cell membranes.

  11. Terahertz detection and carbon nanotubes

    SciTech Connect

    Leonard, Francois

    2014-06-11

    Researchers at Sandia National Laboratories, along with collaborators from Rice University and the Tokyo Institute of Technology, are developing new terahertz detectors based on carbon nanotubes that could lead to significant improvements in medical imaging, airport passenger screening, food inspection and other applications.

  12. Terahertz detection and carbon nanotubes

    ScienceCinema

    Leonard, Francois

    2016-07-12

    Researchers at Sandia National Laboratories, along with collaborators from Rice University and the Tokyo Institute of Technology, are developing new terahertz detectors based on carbon nanotubes that could lead to significant improvements in medical imaging, airport passenger screening, food inspection and other applications.

  13. Carbon Nanotubes and Human Cells?

    ERIC Educational Resources Information Center

    King, G. Angela

    2005-01-01

    Single-walled carbon nanotubes that were chemically altered to be water soluble are shown to enter fibroblasts, T cells, and HL60 cells. Nanoparticles adversely affect immortalized HaCaT human keratinocyte cultures, indicating that they may enter cells.

  14. Thermoelectrics: Carbon nanotubes get high

    NASA Astrophysics Data System (ADS)

    Crispin, Xavier

    2016-04-01

    Waste heat can be converted to electricity by thermoelectric generators, but their development is hindered by the lack of cheap materials with good thermoelectric properties. Now, carbon-nanotube-based materials are shown to have improved properties when purified to contain only semiconducting species and then doped.

  15. Conductance of Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Datta, Supriyo; Anatram, M. P.

    1998-01-01

    The recent report of quantized conductance in a 4 m long multiwalled nanotube (MWNT) raises the exciting possibility of ballistic transport at room temperature over relatively long distances. We argue that this is made possible by the special symmetry of the eigenstates of the lowest propagating modes in metallic nanotubes which suppresses backscattering. This unusual effect is absent for the higher propagating modes so that transport is not ballistic once the bias exceeds the cut-off energy for the higher modes, which is estimated to be approximately 75 meV for nanotubes of diameter approximately 15 nm. Also, we show that the symmetry of the eigenstates can significantly affect their coupling to the reservoir and hence the contact resistance. A simple model is presented that can be used to understand the observed conductance-voltage characteristics.

  16. Nitrated carbon nanoblisters for high-performance glucose dehydrogenase bioanodes.

    PubMed

    de Souza, João C P; Iost, Rodrigo M; Crespilho, Frank N

    2016-03-15

    Recently, many strategies are being explored for efficiently wiring glucose dehydrogenase (GDh) enzymes capable of glucose (fuel) oxidation. For instance, the use of GDh NAD(+)-dependent for glucose oxidation is of great interest in biofuel cell technology because the enzyme are unaffected by the presence of molecular oxygen commonly present in electrolyte. Here we present the fabrication of flexible carbon fibers modified with nitrated carbon nanoblisters and their application as high-performance GDh bioanodes. These bioelectrodes could electro-oxidize glucose at -360 mV (vs. Ag/AgClsat) in the presence of a molecular oxygen saturated electrolyte with current densities higher than 1.0 mAcm(-2) at 0.0 V. It is corroborated by open circuit potential, where a potential stabilization occurs at -150 mV in a long term stability current-transient experiment. This value is in agreement with the quasi-steady current obtained at very low scan rate (0.1 mVs(-1)), where the onset potential for glucose oxidation is -180 mV. X-ray photoelectron spectroscopy and scanning electron microscopy revealed that the nitrated blisters and edge-like carbon structures, enabling highly efficient enzyme immobilization and low overpotential for electron transfer, allowing for glucose oxidation with potential values close to the thermodynamic cofactor.

  17. Peel test of spinnable carbon nanotube webs

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

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

  18. Carbon nanotubes by the metallocene route

    NASA Astrophysics Data System (ADS)

    Sen, Rahul; Govindaraj, A.; Rao, C. N. R.

    1997-03-01

    Pyrolysis of metallocenes such as ferrocene, cobaltocene and nickelocene, is shown to yield carbon nanotubes and metal-filled onion-like structures. Pyrolysis of benzene in the presence of a metallocene gives high yields of nanotubes, the wall thickness of the nanotubes depending on the metallocene content. Pyrolysis of benzene in the absence of any metal however gives monodispersed nanospheres of carbon rather than nanotubes.

  19. Carbon-Nanotube Schottky Diodes

    NASA Technical Reports Server (NTRS)

    Manohara, Harish; Wong, Eric; Schlecht, Erich; Hunt, Brian; Siegel, Peter

    2006-01-01

    Schottky diodes based on semiconducting single-walled carbon nanotubes are being developed as essential components of the next generation of submillimeter-wave sensors and sources. Initial performance predictions have shown that the performance characteristics of these devices can exceed those of the state-of-the-art solid-state Schottky diodes that have been the components of choice for room-temperature submillimeter-wave sensors for more than 50 years. For state-of-the-art Schottky diodes used as detectors at frequencies above a few hundred gigahertz, the inherent parasitic capacitances associated with their semiconductor junction areas and the resistances associated with low electron mobilities limit achievable sensitivity. The performance of such a detector falls off approximately exponentially with frequency above 500 GHz. Moreover, when used as frequency multipliers for generating signals, state-of-the-art solid-state Schottky diodes exhibit extremely low efficiencies, generally putting out only micro-watts of power at frequencies up to 1.5 THz. The shortcomings of the state-of-the-art solid-state Schottky diodes can be overcome by exploiting the unique electronic properties of semiconducting carbon nanotubes. A single-walled carbon nanotube can be metallic or semiconducting, depending on its chirality, and exhibits high electron mobility (recently reported to be approx.= 2x10(exp 5)sq cm/V-s) and low parasitic capacitance. Because of the narrowness of nanotubes, Schottky diodes based on carbon nanotubes have ultra-small junction areas (of the order of a few square nanometers) and consequent junction capacitances of the order of 10(exp -18) F, which translates to cutoff frequency >5 THz. Because the turn-on power levels of these devices are very low (of the order of nano-watts), the input power levels needed for pumping local oscillators containing these devices should be lower than those needed for local oscillators containing state-of-the-art solid

  20. Quantum transport in carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Laird, Edward A.; Kuemmeth, Ferdinand; Steele, Gary A.; Grove-Rasmussen, Kasper; Nygârd, Jesper; Flensberg, Karsten; Kouwenhoven, Leo P.

    2015-07-01

    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 review describes the modern understanding of transport through nanotube devices. Unlike in conventional semiconductors, electrons in nanotubes have two angular momentum quantum numbers, arising from spin and valley freedom. The interplay between the two is the focus of this review. The energy levels associated with each degree of freedom, and the spin-orbit coupling between them, are explained, together with their consequences for transport measurements through nanotube quantum dots. In double quantum dots, the combination of quantum numbers modifies the selection rules of Pauli 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 modifies their transport behavior. Interaction between electrons inside and outside a quantum dot is manifested in SU(4) Kondo behavior and level renormalization. Interaction within a dot leads to Wigner molecules and more complex correlated states. This review takes an experimental perspective informed by recent advances in theory. As well as the well-understood overall picture, open questions for the field are also clearly stated. These advances position nanotubes as a leading system for the study of spin and valley physics in one dimension where electronic disorder and hyperfine interaction can both be reduced to a low level.

  1. Carbon nanotube coatings as chemical absorbers

    DOEpatents

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

    2004-06-15

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

  2. High nitrogen-containing cotton derived 3D porous carbon frameworks for high-performance supercapacitors

    NASA Astrophysics Data System (ADS)

    Fan, Li-Zhen; Chen, Tian-Tian; Song, Wei-Li; Li, Xiaogang; Zhang, Shichao

    2015-10-01

    Supercapacitors fabricated by 3D porous carbon frameworks, such as graphene- and carbon nanotube (CNT)-based aerogels, have been highly attractive due to their various advantages. However, their high cost along with insufficient yield has inhibited their large-scale applications. Here we have demonstrated a facile and easily scalable approach for large-scale preparing novel 3D nitrogen-containing porous carbon frameworks using ultralow-cost commercial cotton. Electrochemical performance suggests that the optimal nitrogen-containing cotton-derived carbon frameworks with a high nitrogen content (12.1 mol%) along with low surface area 285 m2 g-1 present high specific capacities of the 308 and 200 F g-1 in KOH electrolyte at current densities of 0.1 and 10 A g-1, respectively, with very limited capacitance loss upon 10,000 cycles in both aqueous and gel electrolytes. Moreover, the electrode exhibits the highest capacitance up to 220 F g-1 at 0.1 A g-1 and excellent flexibility (with negligible capacitance loss under different bending angles) in the polyvinyl alcohol/KOH gel electrolyte. The observed excellent performance competes well with that found in the electrodes of similar 3D frameworks formed by graphene or CNTs. Therefore, the ultralow-cost and simply strategy here demonstrates great potential for scalable producing high-performance carbon-based supercapacitors in the industry.

  3. High nitrogen-containing cotton derived 3D porous carbon frameworks for high-performance supercapacitors

    PubMed Central

    Fan, Li-Zhen; Chen, Tian-Tian; Song, Wei-Li; Li, Xiaogang; Zhang, Shichao

    2015-01-01

    Supercapacitors fabricated by 3D porous carbon frameworks, such as graphene- and carbon nanotube (CNT)-based aerogels, have been highly attractive due to their various advantages. However, their high cost along with insufficient yield has inhibited their large-scale applications. Here we have demonstrated a facile and easily scalable approach for large-scale preparing novel 3D nitrogen-containing porous carbon frameworks using ultralow-cost commercial cotton. Electrochemical performance suggests that the optimal nitrogen-containing cotton-derived carbon frameworks with a high nitrogen content (12.1 mol%) along with low surface area 285 m2 g−1 present high specific capacities of the 308 and 200 F g−1 in KOH electrolyte at current densities of 0.1 and 10 A g−1, respectively, with very limited capacitance loss upon 10,000 cycles in both aqueous and gel electrolytes. Moreover, the electrode exhibits the highest capacitance up to 220 F g−1 at 0.1 A g−1 and excellent flexibility (with negligible capacitance loss under different bending angles) in the polyvinyl alcohol/KOH gel electrolyte. The observed excellent performance competes well with that found in the electrodes of similar 3D frameworks formed by graphene or CNTs. Therefore, the ultralow-cost and simply strategy here demonstrates great potential for scalable producing high-performance carbon-based supercapacitors in the industry. PMID:26472144

  4. Synthesis, assembly, and applications of single-walled carbon nanotube

    NASA Astrophysics Data System (ADS)

    Ryu, Koungmin

    This dissertation presents the synthesis and assembly of aligned carbon nanotubes, and their applications in both nano-electronics such as transistor and integrated circuits and macro-electronics in energy conversion devices as transparent conducting electrodes. Also, the high performance chemical sensor using metal oxide nanowire has been demonstrated. Chapter 1 presents a brief introduction of carbon nanotube, followed by discussion of a new synthesis technique using nanosphere lithography to grow highly aligned single-walled carbon nanotubes atop quartz and sapphire substrates. This method offers great potential to produce carbon nanotube arrays with simultaneous control over the nanotube orientation, position, density, diameter and even chirality. Chapter 3 introduces the wafer-scale integration and assembly of aligned carbon nanotubes, including full-wafer scale synthesis and transfer of massively aligned carbon nanotube arrays, and nanotube device fabrication on 4 inch Si/SiO2 wafer to yield submicron channel transistors with high on-current density ˜ 20 muA/mum and good on/off ratio and CMOS integrated circuits. In addition, various chemical doping methods for n-type nanotube transistors are studied to fabricate CMOS integrated nanotube circuits such as inverter, NAND and NOR logic devices. Furthermore, defect-tolerant circuit design for NAND and NOR is proposed and demonstrated to guarantee the correct operation of logic circuit, regardless of the presence of mis-aligned or mis-positioned nanotubes. Carbon nanotube flexible electronics and smart textiles for ubiquitous computing and sensing are demonstrated in chapter 4. A facile transfer printing technique has been introduced to transfer massively aligned single-walled carbon nanotubes from the original sapphire/quartz substrates to virtually any other substrates, including glass, silicon, polymer sheets, and even fabrics. The characterization of transferred nanotubes reveals that the transferred

  5. Method of making carbon nanotube composite materials

    DOEpatents

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

    2014-05-20

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

  6. Carbon Nanotube Array for Infrared Detection

    DTIC Science & Technology

    2011-09-28

    REPORT Carbon Nanotube Array for Infrared Detection 14. ABSTRACT 16. SECURITY CLASSIFICATION OF: The core effort of this project has been the electrical...transport and infrared photoresponse properties of carbon nanotube (CNT) systems. 1. REPORT DATE (DD-MM-YYYY) 4. TITLE AND SUBTITLE 13-06-2012 13...DATES COVERED (From - To) 1-Jul-2008 Standard Form 298 (Rev 8/98) Prescribed by ANSI Std. Z39.18 - 30-Jun-2011 Carbon Nanotube Array for Infrared

  7. High Performance Palladium Supported on Nanoporous Carbon under Anhydrous Condition

    NASA Astrophysics Data System (ADS)

    Yang, Zehui; Ling, Ying; Zhang, Yunfeng; Xu, Guodong

    2016-11-01

    Due to the high cost of polymer electrolyte fuel cells (PEFCs), replacing platinum (Pt) with some inexpensive metal was carried out. Here, we deposited palladium nanoparticles (Pd-NPs) on nanoporous carbon (NC) after wrapping by poly[2,2‧-(2,6-pyridine)-5,5‧-bibenzimidazole] (PyPBI) doped with phosphoric acid (PA) and the Pd-NPs size was successfully controlled by varying the weight ratio between Pd precursor and carbon support doped with PA. The membrane electrode assembly (MEA) fabricated from the optimized electrocatalyst with 0.05 mgPd cm‑2 for both anode and cathode sides showed a power density of 76 mW cm‑2 under 120 °C without any humidification, which was comparable to the commercial CB/Pt, 89 mW cm‑2 with 0.45 mgPt cm‑2 loaded in both anode and cathode. Meanwhile, the power density of hybrid MEA with 0.45 mgPt cm‑2 in cathode and 0.05 mgPd cm‑2 in anode reached 188 mW cm‑2. The high performance of the Pt-free electrocatalyst was attributed to the porous structure enhancing the gas diffusion and the PyPBI-PA facilitating the proton conductivity in catalyst layer. Meanwhile, the durability of Pd electrocatalyst was enhanced by coating with acidic polymer. The newly fabricated Pt-free electrocatalyst is extremely promising for reducing the cost in the high-temperature PEFCs.

  8. High Performance Palladium Supported on Nanoporous Carbon under Anhydrous Condition

    PubMed Central

    Yang, Zehui; Ling, Ying; Zhang, Yunfeng; Xu, Guodong

    2016-01-01

    Due to the high cost of polymer electrolyte fuel cells (PEFCs), replacing platinum (Pt) with some inexpensive metal was carried out. Here, we deposited palladium nanoparticles (Pd-NPs) on nanoporous carbon (NC) after wrapping by poly[2,2′-(2,6-pyridine)-5,5′-bibenzimidazole] (PyPBI) doped with phosphoric acid (PA) and the Pd-NPs size was successfully controlled by varying the weight ratio between Pd precursor and carbon support doped with PA. The membrane electrode assembly (MEA) fabricated from the optimized electrocatalyst with 0.05 mgPd cm−2 for both anode and cathode sides showed a power density of 76 mW cm−2 under 120 °C without any humidification, which was comparable to the commercial CB/Pt, 89 mW cm−2 with 0.45 mgPt cm−2 loaded in both anode and cathode. Meanwhile, the power density of hybrid MEA with 0.45 mgPt cm−2 in cathode and 0.05 mgPd cm−2 in anode reached 188 mW cm−2. The high performance of the Pt-free electrocatalyst was attributed to the porous structure enhancing the gas diffusion and the PyPBI-PA facilitating the proton conductivity in catalyst layer. Meanwhile, the durability of Pd electrocatalyst was enhanced by coating with acidic polymer. The newly fabricated Pt-free electrocatalyst is extremely promising for reducing the cost in the high-temperature PEFCs. PMID:27811971

  9. Carbon Nanotube Thermoelectric Coolers

    DTIC Science & Technology

    2015-02-06

    The cooling cycle : The electric current pulls out the electron and hole excitations from the central region of the nanotube. (c) The heating cycle ...thermoelectric heating and cooling cycles . The sharp features in the  eG V curve corresponding to energy levels EC localized in the active region...liquid nitrogen temperature 77T  K up to hot 134 8T  K, or decreases from 77T  K down to about cold 20 6T  K, thus evidencing a strong

  10. Torsional carbon nanotube artificial muscles.

    PubMed

    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.

  11. Ballistic Fracturing of Carbon Nanotubes.

    PubMed

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

    2016-09-21

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

  12. Carbon Nanotubes: Molecular Electronic Components

    NASA Technical Reports Server (NTRS)

    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.

  13. Torsional Carbon Nanotube Artificial Muscles

    NASA Astrophysics Data System (ADS)

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

    2011-10-01

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

  14. Multilayer Film Assembly of Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Cassell, Alan M.; Meyyappan, M.; Han, Jie; Arnold, J. (Technical Monitor)

    2000-01-01

    An approach to assemble multilayers of carbon nanotubes on a substrate is presented. Chemical vapor deposition using a transition metal catalyst formulation is used to grow the nanotubes. Results show a bilayer assembly of nanotubes each with a different density of tubes.

  15. Use of nanoparticles and nanotubes for the development of high-performance nanoresins and nanocomposites

    NASA Astrophysics Data System (ADS)

    Gudapati, Vamshi

    2011-12-01

    In this study, a brittle epoxy polymer resin has successfully been toughened and strengthened by very small concentrations of diamond and SiC nanoparticles as well as Nanodiamonds (collectively called "nanoparticles" here). The tensile stress-strain response (based on the ASTM tensile tests for polymers) and the fracture energy release rate, GIC, (based on the ASTM Single-Edge-Notched-Bending, SENB, tests for polymers) of neat and nano-reinforced epoxy polymer were characterized over a range of "nanoparticle" concentrations. In addition to the large-scale improvements in mechanical properties, the nanoresins developed in this work also showed other superior multifunctional performances such as structural damping and acoustic properties. In the later part of this study, horizontally (in-plane, i.e., completely parallel to the surface) aligned multi-walled carbon nanotube (MWCNT with diameters of less than 100 nm) nanocarpet-nanotapes are developed as reinforcements to enhance the overall performance of resins, adhesives, and composites, globally (when it is interleaved within the composites to cover or "carpet" the entire surface of the parts) or locally (when it is used to locally reinforce the locations of joints, cut-outs, holes, etc, where stress concentrations exist). In addition to large scale improvements in mechanical properties, the nanocomposites developed in this work also showed enhanced multifunctional performance such as damping, electro-magnetic interference shielding (EMI), coefficient of thermal expansion (CTE), and Thermal Conductivity. Finally, we report the use of chemically modified vertically aligned carbon nanotube nanoforest nanofilm directly assembled on carbon paper as Gas Diffusion Layers (GDLs) for fuel cells. GDLs enhance the delivery of gases to the catalyst layers by controlling the water in the pore channels while simultaneously completing the electrical and electronic circuits needed to deliver the power generated by the Proton

  16. Carbon Nanotube Field Emission Arrays

    DTIC Science & Technology

    2011-06-01

    deposition (PE-CVD), which is a hybrid of plasma based and thermal based synthesis, and silicon carbide ( SiC ) surface decomposition which, though a true...fabrication method. 2.4.3.2. Surface Decomposition The fabrication of carbon nanotubes by surface decomposition of silicon carbide offers some unique...CNTs are vertically aligned and attached to the remaining silicon carbide substrate. Surface decomposition is achieved through high temperatures in a

  17. Nanospot welding of carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Hirayama, H.; Kawamoto, Y.; Ohshima, Y.; Takayanagi, K.

    2001-08-01

    Single wall carbon nanotube (SWNT) bundles protruding from the SWNT layers on self-aligned Sn apexes were brought to a distance of 30 nm by a scanning tunneling microscope inside a transmission electron microscope. A straight bundle on the tip could be observed in situ in contact electrostatically with a looped bundle on the sample by applying tip bias voltages above 2.0 V. The bundles were welded at the nanometer size contact area by local Joule heating.

  18. From carbon nanobells to nickel nanotubes

    NASA Astrophysics Data System (ADS)

    Ma, S.; Srikanth, V. V. S. S.; Maik, D.; Zhang, G. Y.; Staedler, T.; Jiang, X.

    2009-01-01

    A generic strategy is proposed to prepare one dimensional (1D) metallic nanotubes by using 1D carbon nanostructures as the initial templates. Following the strategy, nickel (Ni) nanotubes are prepared by using carbon nanobells (CNBs) as the initial templates. CNBs are first prepared by microwave plasma enhanced chemical vapor deposition technique. Carbon/nickel core/shell structures are then prepared by electroplating the CNBs in a nickel-Watts electrolytic cell. In the final step, the carbon core is selectively removed by employing hydrogen plasma etching to obtain Ni nanotubes. The mechanism leading to Ni nanotubes is briefly discussed.

  19. Thermal conductivity of deformed carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Zhong, Wei-Rong; Zhang, Mao-Ping; Zheng, Dong-Qin; Ai, Bao-Quan

    2011-04-01

    We investigate the thermal conductivity of four types of deformed carbon nanotubes by using the nonequilibrium molecular dynamics method. It is reported that various deformations have different influences on the thermal properties of carbon nanotubes. For bending carbon nanotubes, the thermal conductivity is independent of the bending angle. However, the thermal conductivity increases lightly with xy-distortion and decreases rapidly with z-distortion. The thermal conductivity does not change with the screw ratio before the breaking of carbon nanotubes, but it decreases sharply after the critical screw ratio.

  20. A Thermal Model for Carbon Nanotube Interconnects

    PubMed Central

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

    2013-01-01

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

  1. Carbon nanotubes - curse or blessing.

    PubMed

    Kaiser, J-P; Roesslein, M; Buerki-Thurnherr, T; Wick, P

    2011-01-01

    Although nanotechnology is a relatively new scientific field, quite many different products are already introduced in the market containing nanosized particles. A special class of nanosized materials namely the carbon nanotubes (CNT) possesses outstanding new properties and extraordinary potential for creating new products. Carbon nanotubes are already used in various consumer products, industrial applications and science. It is not as this time clear how CNT are able to affect human health since most types of CNTs differ significantly in terms of structural characteristics (morphology, size, shape and length), surface properties (surface chemistry and surface charge) and chemical composition. This review provides an overview about contradicting reports that are found in the literature. We summarize the studies that report about nontoxic as well as toxic effects of CNT in-vitro and in-vivo. We describe how carbon nanotubes can readily be degraded under certain conditions. Another phenomenon is that despite the observed toxic effects which may occur to cells, organs and animals after uptake of CNT, intensive research investigations were undertaken in order to use these outstanding materials in medical applications. The second part of this review starts with a short description of the main principles in metrology. Observed conflicts were discussed in CNT toxicity assays into terms of measurement science or metrology issues. It was demonstrated that any specification of a measurand is only valid within the given framework. This means that many of the published results are within their measurement framework correct, but there are no means to compare them outside this framework.

  2. Torsional electromechanical quantum oscillations in carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Cohen-Karni, Tzahi; Segev, Lior; Srur-Lavi, Onit; Cohen, Sidney R.; Joselevich, Ernesto

    2006-10-01

    Carbon nanotubes can be distinctly metallic or semiconducting depending on their diameter and chirality. Here we show that continuously varying the chirality by mechanical torsion can induce conductance oscillations, which can be attributed to metal-semiconductor periodic transitions. The phenomenon is observed in multiwalled carbon nanotubes, where both the torque and the current are shown to be carried predominantly by the outermost wall. The oscillation period with torsion is consistent with the theoretical shifting of the corners of the first Brillouin zone of graphene across different sub-bands allowed in the nanotube. Beyond a critical torsion, the conductance irreversibly drops due to torsional failure, allowing us to determine the torsional strength of carbon nanotubes. Carbon nanotubes could be ideal torsional springs for nanoscopic pendulums, because electromechanical detection of motion could replace the microscopic detection techniques used at present. Our experiments indicate that carbon nanotubes could be used as electronic sensors of torsional motion in nanoelectromechanical systems.

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

    PubMed

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

    2001-04-27

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

  4. Improved Process for Fabricating Carbon Nanotube Probes

    NASA Technical Reports Server (NTRS)

    Stevens, R.; Nguyen, C.; Cassell, A.; Delzeit, L.; Meyyappan, M.; Han, Jie

    2003-01-01

    An improved process has been developed for the efficient fabrication of carbon nanotube probes for use in atomic-force microscopes (AFMs) and nanomanipulators. Relative to prior nanotube tip production processes, this process offers advantages in alignment of the nanotube on the cantilever and stability of the nanotube's attachment. A procedure has also been developed at Ames that effectively sharpens the multiwalled nanotube, which improves the resolution of the multiwalled nanotube probes and, combined with the greater stability of multiwalled nanotube probes, increases the effective resolution of these probes, making them comparable in resolution to single-walled carbon nanotube probes. The robust attachment derived from this improved fabrication method and the natural strength and resiliency of the nanotube itself produces an AFM probe with an extremely long imaging lifetime. In a longevity test, a nanotube tip imaged a silicon nitride surface for 15 hours without measurable loss of resolution. In contrast, the resolution of conventional silicon probes noticeably begins to degrade within minutes. These carbon nanotube probes have many possible applications in the semiconductor industry, particularly as devices are approaching the nanometer scale and new atomic layer deposition techniques necessitate a higher resolution characterization technique. Previously at Ames, the use of nanotube probes has been demonstrated for imaging photoresist patterns with high aspect ratio. In addition, these tips have been used to analyze Mars simulant dust grains, extremophile protein crystals, and DNA structure.

  5. Zirconium oxide nanotube-Nafion composite as high performance membrane for all vanadium redox flow battery

    NASA Astrophysics Data System (ADS)

    Aziz, Md. Abdul; Shanmugam, Sangaraju

    2017-01-01

    A high-performance composite membrane for vanadium redox flow battery (VRB) consisting of ZrO2 nanotubes (ZrNT) and perfluorosulfonic acid (Nafion) was fabricated. The VRB operated with a composite (Nafion-ZrNT) membrane showed the improved ion-selectivity (ratio of proton conductivity to permeability), low self-discharge rate, high discharge capacity and high energy efficiency in comparison with a pristine commercial Nafion-117 membrane. The incorporation of zirconium oxide nanotubes in the Nafion matrix exhibits high proton conductivity (95.2 mS cm-1) and high oxidative stability (99.9%). The Nafion-ZrNT composite membrane exhibited low vanadium ion permeability (3.2 × 10-9 cm2 min-1) and superior ion selectivity (2.95 × 107 S min cm-3). The VRB constructed with a Nafion-ZrNT composite membrane has lower self-discharge rate maintaining an open-circuit voltage of 1.3 V for 330 h relative to a pristine Nafion membrane (29 h). The discharge capacity of Nafion-ZrNT membrane (987 mAh) was 3.5-times higher than Nafion-117 membrane (280 mAh) after 100 charge-discharge cycles. These superior properties resulted in higher coulombic and voltage efficiencies with Nafion-ZrNT membranes compared to VRB with Nafion-117 membrane at a 40 mA cm-2 current density.

  6. Strong, light, multifunctional fibers of carbon nanotubes with ultrahigh conductivity.

    PubMed

    Behabtu, Natnael; Young, Colin C; Tsentalovich, Dmitri E; Kleinerman, Olga; Wang, Xuan; Ma, Anson W K; Bengio, E Amram; ter Waarbeek, Ron F; de Jong, Jorrit J; Hoogerwerf, Ron E; Fairchild, Steven B; Ferguson, John B; Maruyama, Benji; Kono, Junichiro; Talmon, Yeshayahu; Cohen, Yachin; Otto, Marcin J; Pasquali, Matteo

    2013-01-11

    Broader applications of carbon nanotubes to real-world problems have largely gone unfulfilled because of difficult material synthesis and laborious processing. We report high-performance multifunctional carbon nanotube (CNT) fibers that combine the specific strength, stiffness, and thermal conductivity of carbon fibers with the specific electrical conductivity of metals. These fibers consist of bulk-grown CNTs and are produced by high-throughput wet spinning, the same process used to produce high-performance industrial fibers. These scalable CNT fibers are positioned for high-value applications, such as aerospace electronics and field emission, and can evolve into engineered materials with broad long-term impact, from consumer electronics to long-range power transmission.

  7. Lipid bilayers covalently anchored to carbon nanotubes.

    PubMed

    Dayani, Yasaman; Malmstadt, Noah

    2012-05-29

    The unique physical and electrical properties of carbon nanotubes make them an exciting material for applications in various fields such as bioelectronics and biosensing. Due to the poor water solubility of carbon nanotubes, functionalization for such applications has been a challenge. Of particular need are functionalization methods for integrating carbon nanotubes with biomolecules and constructing novel hybrid nanostructures for bionanoelectronic applications. We present a novel method for the fabrication of dispersible, biocompatible carbon nanotube-based materials. Multiwalled carbon nanotubes (MWCNTs) are covalently modified with primary amine-bearing phospholipids in a carbodiimide-activated reaction. These modified carbon nanotubes have good dispersibility in nonpolar solvents. Fourier transform infrared (FTIR) spectroscopy shows peaks attributable to the formation of amide bonds between lipids and the nanotube surface. Simple sonication of lipid-modified nanotubes with other lipid molecules leads to the formation of a uniform lipid bilayer coating the nanotubes. These bilayer-coated nanotubes are highly dispersible and stable in aqueous solution. Confocal fluorescence microscopy shows labeled lipids on the surface of bilayer-modified nanotubes. Transmission electron microscopy (TEM) shows the morphology of dispersed bilayer-coated MWCNTs. Fluorescence quenching of lipid-coated MWCNTs confirms the bilayer configuration of the lipids on the nanotube surface, and fluorescence anisotropy measurements show that the bilayer is fluid above the gel-to-liquid transition temperature. The membrane protein α-hemolysin spontaneously inserts into the MWCNT-supported bilayer, confirming the biomimetic membrane structure. These biomimetic nanostructures are a promising platform for the integration of carbon nanotube-based materials with biomolecules.

  8. Plasticity and Kinky Chemistry of Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Srivastava, Deepak; Dzegilenko, Fedor

    2000-01-01

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

  9. CARBON NANOTUBES: PROPERTIES AND APPLICATIONS

    SciTech Connect

    Fischer, John, E.

    2009-07-24

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

  10. Carbon nanotube integrated multifunctional multiscale composites

    NASA Astrophysics Data System (ADS)

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

    2007-07-01

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

  11. Fully printed flexible carbon nanotube photodetectors

    NASA Astrophysics Data System (ADS)

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

    2017-03-01

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

  12. Covalent Sidewall Functionalization of Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Chiang, I.W.; Saini, R. K.; Mickelson, E. T.; Billups, W. E.; Hauge, R. H.; Margrave, J. L.

    2001-01-01

    Progress of fluorination of single-wall carbon nanotubes is being reported. Covalent attachment of alkyl groups including methyl, n-butyl and n-hexyl groups to the sidewalls of single wall carbon nanotubes (SWNTs) has been achieved. Quantitative measurement of the alkylation was done by thermal gravimetric analysis. FTIR, Raman and UV-Vis-NIR were used to characterize these alkylated SWNTs. Application of these nanotubes are being investigated-fibers, composites, batteries, lubricants, etc.

  13. Amorphous Carbon-Boron Nitride Nanotube Hybrids

    NASA Technical Reports Server (NTRS)

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

    2016-01-01

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

  14. A Tunable Carbon Nanotube Oscillator

    NASA Astrophysics Data System (ADS)

    Sazonova, Vera

    2005-03-01

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

  15. Hydrogen Storage in Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

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

    2004-10-01

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

  16. Multiscale Simulations of Carbon Nanotubes and Liquids

    NASA Astrophysics Data System (ADS)

    Koumoutsakos, Petros

    2005-11-01

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

  17. Carbon nanotube electrodes in organic transistors.

    PubMed

    Valitova, Irina; Amato, Michele; Mahvash, Farzaneh; Cantele, Giovanni; Maffucci, Antonio; Santato, Clara; Martel, Richard; Cicoira, Fabio

    2013-06-07

    The scope of this Minireview is to provide an overview of the recent progress on carbon nanotube electrodes applied to organic thin film transistors. After an introduction on the general aspects of the charge injection processes at various electrode-semiconductor interfaces, we discuss the great potential of carbon nanotube electrodes for organic thin film transistors and the recent achievements in the field.

  18. Ophthalmologial Applications of Carbon Nanotube Nanotechology

    NASA Technical Reports Server (NTRS)

    Loftus, David; Girten, Beverly (Technical Monitor)

    2002-01-01

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

  19. Understanding Charge Transport in Mixed Networks of Semiconducting Carbon Nanotubes

    PubMed Central

    2016-01-01

    The ability to select and enrich semiconducting single-walled carbon nanotubes (SWNT) with high purity has led to a fast rise of solution-processed nanotube network field-effect transistors (FETs) with high carrier mobilities and on/off current ratios. However, it remains an open question whether it is best to use a network of only one nanotube species (monochiral) or whether a mix of purely semiconducting nanotubes but with different bandgaps is sufficient for high performance FETs. For a range of different polymer-sorted semiconducting SWNT networks, we demonstrate that a very small amount of narrow bandgap nanotubes within a dense network of large bandgap nanotubes can dominate the transport and thus severely limit on-currents and effective carrier mobility. Using gate-voltage-dependent electroluminescence, we spatially and spectrally reveal preferential charge transport that does not depend on nominal network density but on the energy level distribution within the network and carrier density. On the basis of these results, we outline rational guidelines for the use of mixed SWNT networks to obtain high performance FETs while reducing the cost for purification. PMID:26867006

  20. Nanocapillarity and chemistry in carbon nanotubes

    SciTech Connect

    Ugarte, D.; Chatelain, A.; Heer, W.A. de

    1996-12-13

    Open carbon nanotubes were filled with molten silver nitrate by capillary forces. Only those tubes with inner diameters of 4 nanometers or more were filled, suggesting a capillarity size dependence as a result of the lowering of the nanotube-salt interface energy with increasing curvature of the nanotube walls. Nanotube cavities should also be less chemically reactive than graphite and may serve as nanosize test tubes. This property has been illustrated by monitoring the decomposition of silver nitrate within nanotubes in situ in an electron microscope, which produced chains of silver nanobeads separated by high-pressure gas pockets. 32 refs., 3 figs.

  1. Supported Lipid Bilayer/Carbon Nanotube Hybrids

    NASA Astrophysics Data System (ADS)

    Zhou, Xinjian; Moran-Mirabal, Jose; Craighead, Harold; McEuen, Paul

    2007-03-01

    We form supported lipid bilayers on single-walled carbon nanotubes and use this hybrid structure to probe the properties of lipid membranes and their functional constituents. We first demonstrate membrane continuity and lipid diffusion over the nanotube. A membrane-bound tetanus toxin protein, on the other hand, sees the nanotube as a diffusion barrier whose strength depends on the diameter of the nanotube. Finally, we present results on the electrical detection of specific binding of streptavidin to biotinylated lipids with nanotube field effect transistors. Possible techniques to extract dynamic information about the protein binding events will also be discussed.

  2. Epitaxial Approaches to Carbon Nanotube Organization

    NASA Astrophysics Data System (ADS)

    Ismach, Ariel

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

  3. Carbon nanotube growth density control

    NASA Technical Reports Server (NTRS)

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

    2010-01-01

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

  4. Carbon nanotube interaction with DNA.

    PubMed

    Lu, Gang; Maragakis, Paul; Kaxiras, Efthimios

    2005-05-01

    We investigate a system consisting of B-DNA and an array of (10,0) carbon nanotubes periodically arranged to fit into the major groove of the DNA. We obtain an accurate electronic structure of the combined system, which reveals that it is semiconducting and that the bands on either end of the gap are derived exclusively from one of the two components. We discuss in detail how this system can be used as either an electronic switch involving transport through both components, or as a device for ultrafast DNA sequencing.

  5. Computer generated holograms for carbon nanotube arrays

    NASA Astrophysics Data System (ADS)

    Montelongo, Yunuen; Butt, Haider; Butler, Tim; Wilkinson, Timothy D.; Amaratunga, Gehan A. J.

    2013-05-01

    Multiwalled carbon nanotubes are highly diffractive structures in the optical regime. Their metallic character and large scattering cross-section allow their usage as diffractive elements in Fraunhofer holograms. This work elaborates some important features of the far field diffraction patterns produced from periodic arrays of nanotubes. A theoretical approach for the interaction of arrays of nanotubes with light is presented and a computer generated hologram is calculated by means of periodical patterns. Based on the results, fabrication of carbon nanotube arrays (in holographic patterns) was performed. Experimentally measured diffraction patterns were in good agreement with the calculations.

  6. Computer generated holograms for carbon nanotube arrays.

    PubMed

    Montelongo, Yunuen; Butt, Haider; Butler, Tim; Wilkinson, Timothy D; Amaratunga, Gehan A J

    2013-05-21

    Multiwalled carbon nanotubes are highly diffractive structures in the optical regime. Their metallic character and large scattering cross-section allow their usage as diffractive elements in Fraunhofer holograms. This work elaborates some important features of the far field diffraction patterns produced from periodic arrays of nanotubes. A theoretical approach for the interaction of arrays of nanotubes with light is presented and a computer generated hologram is calculated by means of periodical patterns. Based on the results, fabrication of carbon nanotube arrays (in holographic patterns) was performed. Experimentally measured diffraction patterns were in good agreement with the calculations.

  7. Electrical Switching in Metallic Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Son, Young-Woo; Ihm, Jisoon; Cohen, Marvin L.; Louie, Steven G.; Choi, Hyoung Joon

    2005-11-01

    We present first-principles calculations of quantum transport which show that the resistance of metallic carbon nanotubes can be changed dramatically with homogeneous transverse electric fields if the nanotubes have impurities or defects. The change of the resistance is predicted to range over more than 2 orders of magnitude with experimentally attainable electric fields. This novel property has its origin that backscattering of conduction electrons by impurities or defects in the nanotubes is strongly dependent on the strength and/or direction of the applied electric fields. We expect this property to open a path to new device applications of metallic carbon nanotubes.

  8. Carbon nanotube materials characterization and devices design

    NASA Astrophysics Data System (ADS)

    Li, Weifeng

    The objective of this research is to characterize the electrical and mechanical properties of Carbon Nanotube (CNT) materials, and explore possible device applications for these materials. In order to achieve this goal, different forms of Carbon Nanotube materials---including Carbon Nanotubes, Carbon Nanotube Arrays, Carbon Nanotube Ribbon, Carbon Nanotube Thread, and sub-micrometer Carbon Nanotube Thread---were tested under a Scanning Electron Microscope (SEM) using a Micromanipulator (MM). Video and sound recording of the testing in the microscope provided new understanding how thread is formed and how nanotube materials fail. As-produced and thermally treated nanotubes were also tested. The main electrical parameters measured were electrical resistivity and maximum current density. The main mechanical property measured was strength. Together, these parameters are helping to determine the strongest and most conductive forms of CNT material. Putting nanotube materials into application is the ultimate goal of this continuing research. Several aggressive application ideas were investigated in a preliminary way in this work. In biomedical applications, a bundle of CNTs was formed for use as an electrode for accurate biosensing. A simple robot was designed using CNT electrical fiber. The robot was powered by two solenoids and could act as an in-body sensor and actuator to perform some impossible tasks from the viewpoint of current medical technology. In aerospace engineering, CNT materials could replace copper wire to reduce the weight of aircraft. Based on the excellent mechanical properties of CNT materials, a challenging idea is to use CNT material to build elevators to move payloads to outer space without using rockets. This dissertation makes contributions in the characterization of nanotube materials and in the design of miniature electromagnetic devices.

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

    NASA Astrophysics Data System (ADS)

    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

  10. Functionalization of carbon nanotubes: Characterization, modeling and composite applications

    NASA Astrophysics Data System (ADS)

    Wang, Shiren

    Carbon nanotubes have demonstrated exceptional mechanical, thermal and electrical properties, and are regarded as one of the most promising reinforcement materials for the next generation of high performance structural and multifunctional composites. However, to date, most application attempts have been hindered by several technical roadblocks, such as poor dispersion and weak interfacial bonding. In this dissertation, several innovative functionalization methods were proposed, studied to overcome these technical issues in order to realize the full potential of nanotubes as reinforcement. These functionalization methods included precision sectioning of nanotubes using an ultra-microtome, electron-beam irradiation, amino and epoxide group grafting. The characterization results of atomic force microscope, transmission electronic microscope and Raman suggested that aligned carbon nanotubes can be precisely sectioned with controlled length and minimum sidewall damage. This study also designed and demonstrated new covalent functionalization approaches through unique epoxy-grafting and one-step amino-grafting, which have potential of scale-up for composite applications. In addition, the dissertation also successfully tailored the structure and properties of the thin nanotube film through electron beam irradiation. Significant improvement of both mechanical and electrical conducting properties of the irradiated nanotube films or buckypapers was achieved. All these methods demonstrated effectiveness in improving dispersion and interfacial bonding in the epoxy resin, resulting in considerable improvements in composite mechanical properties. Modeling of functionalization methods also provided further understanding and offered the reasonable explanations of SWNTs length distribution as well as carbon nanostructure transformation upon electron-beam irradiation. Both experimental and modeling results provide important foundations for the further comprehensively investigation of

  11. Development of Carbon-Nanotube/Polymer Composites

    NASA Technical Reports Server (NTRS)

    Reynolds, Thomas A.

    2005-01-01

    A report presents a short discussion of one company's effort to develop composites of carbon nanotubes in epoxy and other polymer matrices. The focus of the discussion is on the desirability of chemically modifying carbon nanotubes to overcome their inherent chemical nonreactivity and thereby enable the formation of strong chemical bonds between nanotubes and epoxies (or other polymeric matrix materials or their monomeric precursors). The chemical modification is effected in a process in which discrete functional groups are covalently attached to the nanotube surfaces. The functionalization process was proposed by the company and demonstrated in practice for the first time during this development effort. The covalently attached functional groups are capable of reacting with the epoxy or other matrix resin to form covalent bonds. Furthermore, the company uses this process to chemically modify the nanotube surfaces, affording tunable adhesion to polymers and solubility in select solvents. Flat-sheet composites containing functionalized nanotubes demonstrate significantly improved mechanical, thermal, and electrical properties.

  12. Stress Calculations for Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Halicioglu, Timur; Langhoff, Stephen R. (Technical Monitor)

    1996-01-01

    Atomic stresses were calculated for carbon nanotubes under strain conditions. Graphitic tubules with radii ranging from approximately 2 to 11 Angstroms and two different tubule structures with varying atomic orientations were included in the calculations. Elongations and contractions were applied in the axial direction and atomic stress values were calculated for infinitely long tubules. The calculations were carried out using Brenner's function which was developed for carbon species. Results indicate that the stress is tensile in the radial direction while it is compressive in the tangential direction. Variations in stress values in the direction of the cylindrical aids were investigated as a function of applied strain. Furthermore, using the stress-strain curve (calculated based on atomic considerations), the values of Young's modulus and Poisson's ratio for nanotubules were also estimated.

  13. Au-decorated sodium titanate nanotubes as high-performance selective photocatalysts for pollutant degradation

    NASA Astrophysics Data System (ADS)

    El Rouby, Waleed M. A.; Comesaña-Hermo, Miguel; Testa-Anta, Martín; Carbó-Argibay, Enrique; Salgueiriño, Verónica; Pérez-Lorenzo, Moisés; Correa-Duarte, Miguel A.

    2017-04-01

    The bioaccumulation of polycyclic aromatic compounds originating from textile processing industries is nowadays a major environmental problem worldwide. In order to tackle this situation, several inorganic semiconductors have been tested as photocatalysts for the degradation of these harmful pollutants in the search of sustainable and cost-effective solutions. Nevertheless, these semiconductor materials often involve important limitations, such as poor efficiency and selectivity, which, in the end, substantially restrict their implementation at the industrial scale. As an alternative, we herein report the fabrication and application of Au-decorated titanate nanotubes (TNTs) as high-performance architectures for the selective degradation of organic contaminants. This synthetic strategy is intended to establish a synergetic integration of the physicochemical and photocatalytic features of these hybrid nanostructures, by combining the remarkable adsorption capabilities of TNTs with the enhanced light-harvesting efficiency provided by the incorporation of a noble metal component. The obtained results evidence the great potential that rationally designed plasmonic composites may have for the development of selective environmental remediation technologies and in particular on the current challenges faced by the wastewater treatment sector.

  14. A Tester for Carbon Nanotube Mode Lockers

    NASA Astrophysics Data System (ADS)

    Song, Yong-Won; Yamashita, Shinji

    2007-05-01

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

  15. Pointwise plucking of suspended carbon nanotubes.

    PubMed

    Luo, Jun; Ouyang, Wengen; Li, Xiaopei; Jin, Zhong; Yang, Leijing; Chen, Changqing; Zhang, Jin; Li, Yan; Warner, Jamie H; Peng, Lian-Mao; Zheng, Quanshui; Zhu, Jing

    2012-07-11

    Vibration of nanotubes/wires is significant for fundamental and applied researches. However, it remains challenging to control the vibration with point-level precision. Herein, individual suspended carbon nanotubes are plucked point by point to vibrate in scanning electron microscope with the electron beam as a nanoscale pointer. The vibration is directly imaged, and its images fit well with simulations from the plucking mechanism. This demonstrates a new way to manipulate the nanotube vibration with unprecedented precision.

  16. Enzymatic degradation of multiwalled carbon nanotubes.

    PubMed

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

    2011-09-01

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

  17. Methods for producing reinforced carbon nanotubes

    DOEpatents

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

    2008-10-28

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

  18. Characterization of Carbon Nanotube Reinforced Nickel

    NASA Technical Reports Server (NTRS)

    Gill, Hansel; Hudson, Steve; Bhat, Biliyar; Munafo, Paul M. (Technical Monitor)

    2002-01-01

    Carbon nanotubes are cylindrical molecules composed of carbon atoms in a regular hexagonal arrangement. If nanotubes can be uniformly dispersed in a supporting matrix to form structural materials, the resulting structures could be significantly lighter and stronger than current aerospace materials. Work is currently being done to develop an electrolyte-based self-assembly process that produces a Carbon Nanotube/Nickel composite material with high specific strength. This process is expected to produce a lightweight metal matrix composite material, which maintains it's thermal and electrical conductivities, and is potentially suitable for applications such as advanced structures, space based optics, and cryogenic tanks.

  19. Carbon nanotube fiber spun from wetted ribbon

    DOEpatents

    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.

  20. A single carbon fiber microelectrode with branching carbon nanotubes for bioelectrochemical processes.

    PubMed

    Zhao, Xueyan; Lu, Xin; Tze, William T Y; Wang, Ping

    2010-06-15

    Carbon fiber electrodes are greatly promising for microelectronic applications including high performance biosensors, miniaturized transmitters, and energy storage and generation devices. For biosensor applications, one drawback of using carbon fiber microelectrodes, especially single fiber electrodes, is the weak electronic signals, a consequence of low surface area of fibers, which ultimately limit the sensitivity of the sensors. In this paper, we report a novel single fiber microelectrode with branched carbon nanotubes for enhanced sensing performance. The fiber microelectrode was prepared from carbonization of cellulose fibers. Upon introduction of carbon nanotubes, the carbon fibers exhibited a significant increase in the specific surface area from <10 to 36.4 m(2)/g (determined by the BET method). A single fiber electrode with such a hierarchical structure was examined for redox reactions of coenzyme NAD(H) which is useful to mediate the assays and transformations of a broad range of biochemicals. Experimental results showed that carbon nanotubes enhanced the redox reactions on surfaces of the electrode by reducing the oxidation potential of NAD(H) from 0.8 to 0.55 V. The single carbon fiber with branched nanotubes was also examined for the detection of glycerol, and the results showed linear responding signals in a concentration range of 40-250 microM. These results are comparable to the properties of fossil-based carbon materials, and thus our cellulose-based carbon electrodes provide a potentially sustainable alternative in bioelectrochemical applications.

  1. Carbon Nanotubes for Human Space Flight

    NASA Technical Reports Server (NTRS)

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

    2003-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2011-05-01

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

  3. Applications and production of carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Hafner, Jason Howard

    Carbon nanotubes, a recently discovered form of carbon fiber with structural perfection similar to that of a fullerene molecule, have interesting electronic, chemical and mechanical properties due to their size and structure. Nanotubes have great potential as a bulk material for strong, lightweight composite materials, and as individual nano-scale tools or devices. Initial work on applications with individual multiwalled nanotubes as field emission sources and scanning force microscopy tips is described. The nanotubes display intriguing field emission behavior interpreted as the nanotube unraveling under the influence of the electric field. The unraveling process is believed to result in facile field emission from linear atomic carbon chains at the end of the nanotube. Such atomic wires represent an excellent field emitter. The work on multiwalled nanotube SFM tips was equally encouraging. The high aspect ratio of the nanotube allows it to image deep trenches inaccessible to commercially available Si pyramidal tips, and it reduces the interaction with the ambient water layer on the sample which perturbs image quality. The most remarkable advantage of nanotube SFM tips is a result of their mechanical properties. It was found that the nanotubes will remain rigid during normal imaging, but conveniently buckle to the side if circumstances arise which create large forces known to damage the tip and sample. This feature makes the tip more durable than Si tips, and is especially important for soft biological samples. In these two applications, as well as others, and in the measurements of novel nanotube properties, high quality, small diameter (0.5 to 2 nm) diameter single-walled nanotubes are most interesting. Such material can be produced slowly and in small amounts by catalytic arc vaporization and catalytic laser vaporization of graphite. It is well known that nanotubes can be mass produced by catalytic chemical vapor deposition (CCVD), but the product consists only

  4. Flightweight Carbon Nanotube Magnet Technology

    NASA Technical Reports Server (NTRS)

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

    2003-01-01

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

  5. Electrically engineered polymer-carbon hybrid heterojunction for high-performance printed transistors

    NASA Astrophysics Data System (ADS)

    Kim, Do Hwan; Kang, Gyu Won; Shin, Hyeon-Jin; Kim, Woo-Jae

    2014-10-01

    Molecularly hybridized materials composed of polymer semiconductors (PSCs) and single-walled carbon nanotubes (SWNTs) may provide a new platform to exploit an advantageous combination of semiconductors, which yields electrical properties that are not available in a single component system. In this talk, we demonstrate high-performance ink-jet printed hybrid transistors with an electrically engineered heterostructure by using specially designed PSCs and semiconducting SWNTs (sc-SWNTs) whose system achieved a high mobility of 0.23 cm2V-1s-1, no Von shift, a low off-current, and good bias-stability. We also revealed that binding energy between PSCs and sc-SWNT was strongly affected by side-chain length of PSCs, leading to the formation of homogeneous nanohybrid film. Eventually, understanding of electrostatic interactions in the heterostructure and experimental results suggest criteria for the design of nanohybrid heterostructures. Acknowledgement. This work was supported by a grant (Code No. 2011-0031628) from the Center for Advanced Soft Electronics under the Global Frontier Research Program of the Ministry of Science, ICT and Future Planning, Korea. The authors acknowledge Prof. Kilwon Cho for collaboration on the analysis of x-ray diffraction.

  6. Deconvoluting hepatic processing of carbon nanotubes

    NASA Astrophysics Data System (ADS)

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

    2016-07-01

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

  7. Carbon Nanotube Composites: Strongest Engineering Material Ever?

    NASA Technical Reports Server (NTRS)

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

    1999-01-01

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

  8. Double-walled carbon nanotube solar cells.

    PubMed

    Wei, Jinquan; Jia, Yi; Shu, Qinke; Gu, Zhiyi; Wang, Kunlin; Zhuang, Daming; Zhang, Gong; Wang, Zhicheng; Luo, Jianbin; Cao, Anyuan; Wu, Dehai

    2007-08-01

    We directly configured double-walled carbon nanotubes as energy conversion materials to fabricate thin-film solar cells, with nanotubes serving as both photogeneration sites and a charge carriers collecting/transport layer. The solar cells consist of a semitransparent thin film of nanotubes conformally coated on a n-type crystalline silicon substrate to create high-density p-n heterojunctions between nanotubes and n-Si to favor charge separation and extract electrons (through n-Si) and holes (through nanotubes). Initial tests have shown a power conversion efficiency of >1%, proving that DWNTs-on-Si is a potentially suitable configuration for making solar cells. Our devices are distinct from previously reported organic solar cells based on blends of polymers and nanomaterials, where conjugate polymers generate excitons and nanotubes only serve as a transport path.

  9. Carbon nanotubes as field emitter.

    PubMed

    Zou, Rujia; Hu, Junqing; Song, Yuelin; Wang, Na; Chen, Huihui; Chen, Haihua; Wu, Jianghong; Sun, Yangang; Chen, Zhigang

    2010-12-01

    Carbon nanotubes (CNTs) have recently emerged as a promising material of electron field emitters. They exhibit extraordinary field emission properties because of their high electrical conductivity, high aspect ratio "needle like" shape for optimum geometrical field enhancement, and remarkable thermal stability. In this Review, we emphasize the estimation and influencing factors of CNTs' emission properties, and discuss in detail the emission properties of macroscopic CNT cathodes, especially fabricated by transplant methods, and describe recent progress on understanding of CNT field emitters and analyze issues related to applications of CNT based cold cathodes in field emission display (FED). We foresee that CNT-FED will take an important place in display technologies in the near future.

  10. Carbon Nanotube Based Light Sensor

    NASA Technical Reports Server (NTRS)

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

    2006-01-01

    A light sensor substrate comprises a base made from a semi-conductive material and topped with a layer of an electrically non-conductive material. A first electrode and a plurality of carbon nanotube (CNT)-based conductors are positioned on the layer of electrically non-conductive material with the CNT-based conductors being distributed in a spaced apart fashion about a periphery of the first electrode. Each CNT-based conductor is coupled on one end thereof to the first electrode and extends away from the first electrode to terminate at a second free end. A second or gate electrode is positioned on the non-conductive material layer and is spaced apart from the second free end of each CNT-based conductor. Coupled to the first and second electrode is a device for detecting electron transfer along the CNT-based conductors resulting from light impinging on the CNT-based conductors.

  11. Photonics based on carbon nanotubes

    PubMed Central

    2013-01-01

    Among direct-bandgap semiconducting nanomaterials, single-walled carbon nanotubes (SWCNT) exhibit strong quasi-one-dimensional excitonic optical properties, which confer them a great potential for their integration in future photonics devices as an alternative solution to conventional inorganic semiconductors. In this paper, we will highlight SWCNT optical properties for passive as well as active applications in future optical networking. For passive applications, we directly compare the efficiency and power consumption of saturable absorbers (SAs) based on SWCNT with SA based on conventional multiple quantum wells. For active applications, exceptional photoluminescence properties of SWCNT, such as excellent light-emission stabilities with temperature and excitation power, hold these nanometer-scale materials as prime candidates for future active photonics devices with superior performances. PMID:23803293

  12. Functionalized carbon nanotubes: biomedical applications

    PubMed Central

    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

  13. Functionalized carbon nanotubes: biomedical applications.

    PubMed

    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.

  14. Carbon Nanotube Tape Vibrating Gyroscope

    NASA Technical Reports Server (NTRS)

    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.

  15. Carbon nanotube polymer composition and devices

    DOEpatents

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

    2011-06-14

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

  16. Carbon nanotube heat-exchange systems

    DOEpatents

    Hendricks, Terry Joseph; Heben, Michael J.

    2008-11-11

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

  17. Fabrication of porous carbon nanotube network.

    PubMed

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

    2008-11-21

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

  18. Lateral force microscopy of multiwalled carbon nanotubes.

    PubMed

    Lievonen, J; Ahlskog, M

    2009-06-01

    Carbon nanotubes are usually imaged with the atomic force microscope (AFM) in non-contact mode. However, in many applications, such as mechanical manipulation or elasticity measurements, contact mode is used. The forces affecting the nanotube are then considerable and not fully understood. In this work lateral forces were measured during contact mode imaging with an AFM across a carbon nanotube. We found that, qualitatively, both magnitude and sign of the lateral forces to the AFM tip were independent of scan direction and can be concluded to arise from the tip slipping on the round edges of the nanotube. The dependence on the normal force applied to the tip and on the ratio between nanotube diameter and tip radius was studied. We show that for small values of this ratio, the lateral force signal can be explained with a simple geometrical model.

  19. The Molecular Design of High-Performance Carbon Materials

    DTIC Science & Technology

    2008-06-30

    with respect to molecular weight, with the dominant species present being methylated derivatives of the polycyclic aromatic hydrocarbons ( PAH ...carbon products. 3. Synthesize pure alkylated polycyclic aromatic hydrocarbons ( PAHs ) with molecular weights (mol wts) in the range of 300-2000. These...response of matrix-assisted, laser desorption ionization time-of- flight mass spectrometry (MALDI-TOF-MS) to alkylated PAH compounds. 4. With MALDI

  20. [Hygienic evaluation of multilayer carbon nanotubes].

    PubMed

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

    2015-01-01

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

  1. Controlled Deposition and Alignment of Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

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

    2009-01-01

    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 carver 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.

  2. Controlled Deposition and Alignment of Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    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.

  3. Nanoparticle Decoration of Carbon Nanotubes by Sputtering

    DTIC Science & Technology

    2013-02-01

    R E N C E S [1] Claussen JC, Franklin AD, Haque AU, Porterfield DM, Fisher TS. Electrochemical biosensor of nanocube-augmented carbon nanotube...applications. Often nanoparti- cles are deposited by electrochemical methods, which gener- ally require time consuming treatments with strong acid for surface...techniques as scalable alternatives to electrochemical treatment for growth of metal nanoparticles on the sidewalls of multi-wall carbon nanotubes (MWCNTs

  4. Carbon nanotube temperature and pressure sensors

    DOEpatents

    Ivanov, Ilia N.; Geohegan, David B.

    2016-12-13

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

  5. Carbon nanotube temperature and pressure sensors

    DOEpatents

    Ivanov, Ilia N.; Geohegan, David B.

    2016-11-15

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

  6. Carbon nanotube temperature and pressure sensors

    DOEpatents

    Ivanov, Ilia N.; Geohegan, David B.

    2016-10-25

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

  7. Carbon nanotube temperature and pressure sensors

    DOEpatents

    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.

  8. Physically unclonable cryptographic primitives using self-assembled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Hu, Zhaoying; Comeras, Jose Miguel M. Lobez; Park, Hongsik; Tang, Jianshi; Afzali, Ali; Tulevski, George S.; Hannon, James B.; Liehr, Michael; Han, Shu-Jen

    2016-06-01

    Information security underpins many aspects of modern society. However, silicon chips are vulnerable to hazards such as counterfeiting, tampering and information leakage through side-channel attacks (for example, by measuring power consumption, timing or electromagnetic radiation). Single-walled carbon nanotubes are a potential replacement for silicon as the channel material of transistors due to their superb electrical properties and intrinsic ultrathin body, but problems such as limited semiconducting purity and non-ideal assembly still need to be addressed before they can deliver high-performance electronics. Here, we show that by using these inherent imperfections, an unclonable electronic random structure can be constructed at low cost from carbon nanotubes. The nanotubes are self-assembled into patterned HfO2 trenches using ion-exchange chemistry, and the width of the trench is optimized to maximize the randomness of the nanotube placement. With this approach, two-dimensional (2D) random bit arrays are created that can offer ternary-bit architecture by determining the connection yield and switching type of the nanotube devices. As a result, our cryptographic keys provide a significantly higher level of security than conventional binary-bit architecture with the same key size.

  9. Physically unclonable cryptographic primitives using self-assembled carbon nanotubes.

    PubMed

    Hu, Zhaoying; Comeras, Jose Miguel M Lobez; Park, Hongsik; Tang, Jianshi; Afzali, Ali; Tulevski, George S; Hannon, James B; Liehr, Michael; Han, Shu-Jen

    2016-06-01

    Information security underpins many aspects of modern society. However, silicon chips are vulnerable to hazards such as counterfeiting, tampering and information leakage through side-channel attacks (for example, by measuring power consumption, timing or electromagnetic radiation). Single-walled carbon nanotubes are a potential replacement for silicon as the channel material of transistors due to their superb electrical properties and intrinsic ultrathin body, but problems such as limited semiconducting purity and non-ideal assembly still need to be addressed before they can deliver high-performance electronics. Here, we show that by using these inherent imperfections, an unclonable electronic random structure can be constructed at low cost from carbon nanotubes. The nanotubes are self-assembled into patterned HfO2 trenches using ion-exchange chemistry, and the width of the trench is optimized to maximize the randomness of the nanotube placement. With this approach, two-dimensional (2D) random bit arrays are created that can offer ternary-bit architecture by determining the connection yield and switching type of the nanotube devices. As a result, our cryptographic keys provide a significantly higher level of security than conventional binary-bit architecture with the same key size.

  10. Analysis of Carbon Nanotube Field-Effect-Transistors (FETs)

    NASA Technical Reports Server (NTRS)

    Yamada, Toshishige

    1999-01-01

    This five page presentation is grouped into 11 numbered viewgraphs, most of which contain one or more diagrams. Some of the diagrams are accompanied by captions, including: 2) Nanotube FET by Delft, IBM; 3) Nanotube FET/Standard MOSFET; 5) Saturation with carrier-carrier; 7) Electronic properties of carbon nanotube; 8) Theoretical nanotube FET characteristics; 11) Summary: Delft and IBM nanotube FET analysis.

  11. Filling of carbon nanotubes and nanofibres

    PubMed Central

    Gately, Reece D

    2015-01-01

    Summary The reliable production of carbon nanotubes and nanofibres is a relatively new development, and due to their unique structure, there has been much interest in filling their hollow interiors. In this review, we provide an overview of the most common approaches for filling these carbon nanostructures. We highlight that filled carbon nanostructures are an emerging material for biomedical applications. PMID:25821693

  12. A monolithic functional film of nanotubes/cellulose/ionic liquid for high performance supercapacitors

    NASA Astrophysics Data System (ADS)

    Basiricò, Lucia; Lanzara, Giulia

    2014-12-01

    A novel monolithic, pre-fabricated, fully functional film made of a nanostructured free-standing layer is presented for a new and competitive class of easy-to-assemble flexible supercapacitors whose design is in-between the all solid state and the traditional liquid electrolyte. The film is made of two vertically aligned multi-walled carbon nanotube (VANT) electrodes that store ions, embedded-in, and monolithically interspaced by a solution of microcrystalline cellulose in a room temperature ionic liquid (RTIL) electrolyte (1-ethyl-3-methylimidazolium acetate-EMIM Ac). The fine tuning of VANTs length and electrolyte/cellulose amount leads, in a sole and continuous block, to ions storage and physical separation between the electrodes without the need of the additional separator layer that is typically used in supercapacitors. Thus, physical discontinuities that can induce disturbances to ions mobility, are fully eliminated significantly reducing the equivalent series resistance and increasing the knee frequency, hence outclassing the best supercapacitors based on VANTs and non-aqueous electrolytes. The excellent electrochemical response can also be addressed to the chosen electrolyte that, not only has the advantage of leading to a significantly simpler and more affordable fabrication procedure, but has higher ionic conductivity, lower viscosity and higher ions mobility than other electrolytes capable of dissolving cellulose.

  13. Method for manufacturing high quality carbon nanotubes

    NASA Technical Reports Server (NTRS)

    Benavides, Jeanette M. (Inventor)

    2006-01-01

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

  14. Nitrogen-doped mesoporous carbons for high performance supercapacitors

    NASA Astrophysics Data System (ADS)

    Wu, Kai; Liu, Qiming

    2016-08-01

    The mesoporous carbons have been synthesized by using α-D(+)-Glucose, D-Glucosamine hydrochloride or their mixture as carbon precursors and mesoporous silicas (SBA-15 or MCF) as hard templates. The as-prepared products show a large pore volume (0.59-0.97 cm3 g-1), high surface areas (352.72-1152.67 m2 g-1) and rational nitrogen content (ca. 2.5-3.9 wt.%). The results of electrochemical tests demonstrate that both heteroatom doping and suitable pore structure play a decisive role in the performance of supercapacitors. The representative sample of SBA-15 replica obtained using D-Glucosamine hydrochloride only exhibits high specific capacitance (212.8 F g-1 at 0.5 A g-1) and good cycle durability (86.1% of the initial capacitance after 2000 cycles) in 6 M KOH aqueous electrolyte, which is attributed to the contribution of double layer capacitance and pseudo-capacitance. The excellent electrochemical performance makes it a promising electrode material for supercapacitors.

  15. Method for nano-pumping using carbon nanotubes

    DOEpatents

    Insepov, Zeke; Hassanein, Ahmed

    2009-12-15

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

  16. Fast readout of carbon nanotube mechanical resonators

    NASA Astrophysics Data System (ADS)

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

    2013-03-01

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

  17. Carbon nanotubes/TiO2 nanotubes hybrid supercapacitor.

    PubMed

    Wang, Qiang; Wen, Zhenhai; Li, Jinghong

    2007-09-01

    The rational selection and assembly of materials are central issues in the development of energy conversion and storage applications. Incorporating the utilization of carbon nanotubes cathode and TiO2 nanotubes anode in energy storage, a nonaqueous hybrid supercapacitor was developed in order to significantly increase the energy density of the supercapacitor. The electrochemical performance of the hybrid supercapacitor is characterized by charge/discharge test and cyclic voltam-mograms. According to the voltage value, the energy density of the asymmetric supercapacitor, by applying a potential varying from 0 to 2.8 V, is found to be 14.4 Wh/kg at upwards of 10 C, which is twice more than for the conventional symmetric supercapacitor utilizing carbon nanotubes, while maintaining desirable cycling stability and rate capability.

  18. Carbon Nanotube Based Microfluidic Elements for Filtration and Concentration

    SciTech Connect

    Bakajin, O; Ben-Barak, N; Peng, J; Noy, A

    2003-06-25

    We have developed a method for integration of patterned arrays of carbon nanotubes or the ''nanotube mesh'' into microfabricated channels. The method includes standard lithographic methods for patterning and etching the substrate, followed by catalyst patterning, CVD deposition of nanotubes, and anodic bonding of coverslip top. We will describe a carbon nanotube filtering device fabricated using this method and discuss the use of carbon nanotube arrays as molecular concentration and separation media.

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

    PubMed

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

    2004-05-07

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

  20. Optical properties of carbon nanotubes

    NASA Astrophysics Data System (ADS)

    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 < 1 nm) tubes. The energy of optical transitions between van Hove singularities in the electronic density of states computed from the "zone-folding" model (with gamma0 = 2.9 eV) agree well with the resonant conditions for Raman scattering. Small diameter tubes were found to exhibit additional sharp Raman bands in the frequency range 500-1200 cm-1 with an, as yet, undetermined origin. The Raman spectrum of a DWNT was found to be well described by a superposition of the Raman spectra expected for inner and outer tubes, i.e., no charge transfer occurs and the weak van der Waals (vdW) interaction between tubes does not have significant impact on the phonons. A ˜7 cm-1 downshift of the small diameter, inner-tube tangential mode frequency was observed, however, but attributed to a tube wall curvature 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

  1. Polymerization initated at sidewalls of carbon nanotubes

    NASA Technical Reports Server (NTRS)

    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.

  2. Nanoprocessing and nanomeasurements of carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Lin, Xiwei

    A piezoelectric nanomanipulator inside a Transmission Electron Microscope (TEM) specimen holder has been developed, which is capable of manipulating a probe three-dimensionally in translation ranges wider than 40 mum with a positional control precision better than 0.4 nm, and meanwhile allows applying electrical potential across the probe and a sample. The nanomanipulator in TEM permits handling objects of small size with nanometer resolution under real-time TEM inspection, measuring the mechanical and electrical properties of the sample at specified locations, and, at the same time, analyzing the structures of the sample using various TEM techniques. The nanomanipulator in TEM was exploited as an effective tool to measure the electron transport properties of individual carbon nanotubes in contact with a copper probe, and to process multi-walled carbon nanotubes precisely by varieties of approaches, such as nano-welding, nano-cutting, peeling off the outer shells of multi-walled nanotubes. These approaches provide a controllable and reliable method to tailor carbon nanotubes into highly desirable geometry with an ideal number of the shells for many practical applications. The nanomanipulator in TEM was also used to study the field emission of carbon nanotubes by mounting single characterized nanotubes on the probe as the field emitters. It was found that the effective energy barrier for emitting electrons from nanotube tips is lower than the work function of graphite, which is responsible for the good field emission characteristics of carbon nanotubes as well as their high aspect ratio. The strong attractive interaction between carbon nanotube tips and in-situ carbon nanowire growth induced by a high electrical field were first observed using the nanomanipulator in TEM. Electron holography was employed to investigate the nanoscale features of carbon nanotubes and their particulate derivatives. Reconstructed phase images of holograms offer a quantitative means to

  3. Lysozyme binds onto functionalized carbon nanotubes.

    PubMed

    Bomboi, Francesca; Tardani, Franco; Gazzoli, Delia; Bonincontro, Adalberto; La Mesa, Camillo

    2013-08-01

    Single walled carbon nanotubes have singular physicochemical properties making them attractive in a wide range of applications. Studies on carbon nanotubes and biological macromolecules exist in literature. However, ad hoc investigations are helpful to better understand the interaction mechanisms. We report on a system consisting of single walled carbon nanotubes and lysozyme. The phenomenology of nanotube-protein interactions and its effects on protein conformation were determined. We investigated the formation of oxidized nanotube-lysozyme conjugates, by studying the effect of both protein concentration and pH. Electrophoretic mobility, dielectric spectroscopy and dynamic light scattering were used to determine the interaction pathways, monitoring the surface charge density and the size of the complexes. The results allowed identifying the conditions of surface saturation at different pH values. The secondary structure of nanotube-adsorbed protein was controlled by circular dichroism; it was observed that it substantially retains its native conformation. Interestingly, we found that the interactions among oxidized nanotubes and lysozyme molecules are mainly of electrostatic nature and easily tunable by varying the pH of the solutions.

  4. Modeling of carbon nanotubes and carbon nanotube-polymer composites

    NASA Astrophysics Data System (ADS)

    Pal, G.; Kumar, S.

    2016-01-01

    In order to meet stringent environmental, safety and performance requirements from respective regulatory bodies, various technology-based industries are promoting the use of advanced carbon nanotube (CNT) reinforced lightweight and high strength polymer nanocomposites (PNCs) as a substitute to conventional materials both in structural and non-structural applications. The superior mechanical properties of PNCs made up of CNTs or bundles of CNTs can be attributed to the interfacial interaction between the CNTs and matrix, CNT's morphologies and to their uniform dispersion in the matrix. In PNCs, CNTs physically bond with polymeric matrix at a level where the assumption of continuum level interactions is not applicable. Modeling and prediction of mechanical response and failure behavior of CNTs and their composites becomes a complex task and is dealt with the help of up-scale modeling strategies involving multiple spatial and temporal scales in hierarchical or concurrent manner. Firstly, the article offers an insight into various modeling techniques in studying the mechanical response of CNTs; namely, equivalent continuum approach, quasi-continuum approach and molecular dynamics (MD) simulation. In the subsequent steps, these approaches are combined with analytical and numerical micromechanics models in a multiscale framework to predict the average macroscopic response of PNCs. The review also discusses the implementation aspects of these computational approaches, their current status and associated challenges with a future outlook.

  5. Oscillatory characteristics of carbon nanotubes inside carbon nanotube bundles

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

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

  6. Carbon Nanotube Thin Film Transistors for Flat Panel Display Application.

    PubMed

    Liang, Xuelei; Xia, Jiye; Dong, Guodong; Tian, Boyuan; Peng, Lianmao

    2016-12-01

    Carbon nanotubes (CNTs) are promising materials for both high performance transistors for high speed computing and thin film transistors for macroelectronics, which can provide more functions at low cost. Among macroelectronics applications, carbon nanotube thin film transistors (CNT-TFT) are expected to be used soon for backplanes in flat panel displays (FPDs) due to their superior performance. In this paper, we review the challenges of CNT-TFT technology for FPD applications. The device performance of state-of-the-art CNT-TFTs are compared with the requirements of TFTs for FPDs. Compatibility of the fabrication processes of CNT-TFTs and current TFT technologies are critically examined. Though CNT-TFT technology is not yet ready for backplane production line of FPDs, the challenges can be overcome by close collaboration between research institutes and FPD manufacturers in the short term.

  7. Flexible symmetric supercapacitors based on vertical TiO2 and carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Chien, C. J.; Chang, Pai-Chun; Lu, Jia G.

    2010-03-01

    Highly conducting and porous carbon nanotubes are widely used as electrodes in double-layer-effect supercapacitors. In this presentation, vertical TiO2 nanotube array is fabricated by anodization process and used as supercapacitor electrode utilizing its compact density, high surface area and porous structure. By spin coating carbon nanotube networks on vertical TiO2 nanotube array as electrodes with 1M H2SO4 electrolyte in between, the specific capacitance can be enhanced by 30% compared to using pure carbon nanotube network alone because of the combination of double layer effect and redox reaction from metal oxide materials. Based on cyclic voltammetry and galvanostatic charge-discharge measurements, this type of hybrid electrode has proven to be suitable for high performance supercapacitor application and maintain desirable cycling stability. The electrochemical impedance spectroscopy technique shows that the electrode has good electrical conductivity. Furthermore, we will discuss the prospect of extending this energy storage approach in flexible electronics.

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

    PubMed

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

    2010-08-01

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

  9. Carbon Nanotube Suspensions: some underlying issues

    NASA Astrophysics Data System (ADS)

    Windle, Alan

    2006-03-01

    Entropy of mixing of rigid particles in a suspending medium is determined on a per-particle basis and thus, for a given weight fraction will decrease with increasing particle size. In the case of carbon nanotubes, the entropy contribution to mixing will thus be small compared with the interparticle forces which comprise the enthalpic energy contribution to any thermodynamic equilibrium. These forces will generally be short range with the exception of electrostatic forces in the cases that the particles carry a charge. The ability to form carbon nanotube suspensions depends on both the chemical affinity between the medium and the tubes and, it appears, the size of the medium molecules. Surface treatments of the nanotubes have been developed both using covalently attached functional groups and surfactants, and each strategy has been successfully applied to both multi and single wall CNTs. Because carbon nanotubes are long, thin, rigid and comparatively straight, they have been shown to self assemble into liquid crystalline phases showing all the attributes of conventional systems. The relationship between such CNT systems and the conventional ‘Flory’ phase diagram will be described, as will the exploitation of these phase equilibria to fractionate nanotubes on the basis of mesogenicity. The use of liquid crystalline phases as a basis for the processing of carbon nanotubes into aligned assemblies such as fibres will also be outlined.

  10. Carbon Nanotube-Based Synthetic Gecko Tapes

    NASA Astrophysics Data System (ADS)

    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.

  11. Carbon nanotubes: Synthesis, integration and properties

    NASA Astrophysics Data System (ADS)

    Kong, Jing

    Ever since their discovery in 1991, carbon nanotubes have captured the attention of researchers worldwide due to their remarkable structural, electrical and mechanical properties. They not only offer an ideal playground for fundamental research but also render great potential for all kinds of applications, including future electronic devices, sensors, exceptionally strong materials, flat-panel displays, hydrogen fuel cells, and so on. This thesis reports the study of nanotube properties and some of its applications. It is divided into three parts: (1) The chemical synthesis of individual single-walled nanotubes (SWNTs) via chemical vapor deposition of methane; (2) the integration of individual SWNT into electronic circuits; (3) The studies on the electrical properties of these nanotubes, and the exploration of their potential applications. In order to facilitate the studies and applications of nanotubes, great efforts have been made towards their synthesis and production. Our approach is the chemical vapor deposition (CVD) method, through which we can produce individual SWNTs with high quality and high yield. However, the nanotubes produced directly using CVD (and other methods like laser ablation and arc discharge) are always tangled and bundled up together, and buried inside the graphitized bulk catalyst, which renders the manipulation and characterization a difficult task. We solved this problem by combining the chemical synthesis and conventional nanofabrication techniques together with selectively growing nanotubes at specific sites. Therefore, individual carbon nanotubes can be easily integrated into electrical circuits. Theoretical studies have shown nanotubes possess unique electronic properties; a SWNT be metallic, semiconducting or semi-metallic depending on its helicity. In our experimental studies we have observed all the 3 types of behaviors and confirmed the theoretical predictions. We also investigated the realization of various nanotube functional

  12. Selective Functionalization of Carbon Nanotubes: Part II

    NASA Technical Reports Server (NTRS)

    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

  13. Three-dimensional nanotube electrode arrays for hierarchical tubular structured high-performance pseudocapacitors

    NASA Astrophysics Data System (ADS)

    Gao, Yuan; Lin, Yuanjing; Chen, Jiaqi; Lin, Qingfeng; Wu, Yue; Su, Wenjun; Wang, Wenli; Fan, Zhiyong

    2016-07-01

    Ordered three-dimensional (3-D) tubular arrays are highly attractive candidates for high performance pseudocapacitor electrodes. Here, we report 3-D fluorine doped tin oxide (FTO) tubular arrays fabricated by a cost-effective ultrasonic spray pyrolysis (USP) method in anodic aluminum oxide (AAO) channels with high uniformity. The large surface area of such a structure leads to remarkable surface area enhancement up to 51.8 times compared to a planar structure. Combining with electrochemically deposited manganese dioxide (MnO2) nanoflakes on the inner side wall of the FTO nanotubes, the unique hierarchical tubular structured pseudocapacitor electrode demonstrated the highest areal capacitance of 193.8 mF cm-2 at the scan rate of 5 mV s-1 and 184 mF cm-2 at the discharge current density of 0.6 mA cm-2, which is 18.5 times that of a planar electrode. And it also showed a volumetric capacitance of 112.6 F cm-3 at the scan rate of 5 mV s-1 and 108.8 F cm-3 at the discharge current density of 0.6 mA cm-2. In addition, the cyclic stability test also indicated that a nanostructured pseudocapacitive electrode has a much larger capacitance retention after 3000 cycles of the charge-discharge process compared with a planar electrode, primarily due to the mechanical stability of the nanostructure. Moreover, pseudocapacitor device fabrication based on such electrodes shows the volumetric capacitance of 17.5 F cm-3, and the highest specific energy of 1.56 × 10-3 Wh cm-3. With the merit of facile fabrication procedures and largely enhanced electrochemical performance, such a 3-D structure has high potency for energy storage systems for a wide range of practical applications.Ordered three-dimensional (3-D) tubular arrays are highly attractive candidates for high performance pseudocapacitor electrodes. Here, we report 3-D fluorine doped tin oxide (FTO) tubular arrays fabricated by a cost-effective ultrasonic spray pyrolysis (USP) method in anodic aluminum oxide (AAO) channels with

  14. Carbon Nanotube Reinforced Polymers for Radiation Shielding Applications

    NASA Technical Reports Server (NTRS)

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

    2004-01-01

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

  15. A carbon nanotube wall membrane for water treatment.

    PubMed

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

    2015-05-14

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

  16. Release characteristics of selected carbon nanotube polymer composites

    EPA Science Inventory

    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 ...

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

    NASA Technical Reports Server (NTRS)

    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.

  18. A carbon nanotube wall membrane for water treatment

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

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

  19. Building robust architectures of carbon and metal oxide nanocrystals toward high-performance anodes for lithium-ion batteries.

    PubMed

    Jia, Xilai; Chen, Zheng; Cui, Xia; Peng, Yiting; Wang, Xiaolei; Wang, Ge; Wei, Fei; Lu, Yunfeng

    2012-11-27

    Design and fabrication of effective electrode structure is essential but is still a challenge for current lithium-ion battery technology. Herein we report the design and fabrication of a class of high-performance robust nanocomposites based on iron oxide spheres and carbon nanotubes (CNTs). An efficient aerosol spray process combined with vacuum filtration was used to synthesize such composite architecture, where oxide nanocrystals were assembled into a continuous carbon skeleton and entangled in porous CNT networks. This material architecture offers many critical features that are required for high-performance anodes, including efficient ion transport, high conductivity, and structure durability, therefore enabling an electrode with outstanding lithium storage performance. For example, such an electrode with a thickness of ∼35 μm could deliver a specific capacity of 994 mA h g(-1) (based on total electrode weight) and high recharging rates. This effective strategy can be extended to construct many other composite electrodes for high-performance lithium-ion batteries.

  20. Carbon Nanotube-Based Permeable Membranes

    SciTech Connect

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

    2004-04-06

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

  1. Carbon Nanotube Tower-Based Supercapacitor

    NASA Technical Reports Server (NTRS)

    Meyyappan, Meyya (Inventor)

    2012-01-01

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

  2. Electrical Switching in Metallic Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Choi, Hyoung Joon; Son, Young-Woo; Ihm, Jisoon; Cohen, Marvin L.; Louie, Steven G.

    2006-03-01

    We present first-principles calculations of quantum transport which show that the resistance of metallic carbon nanotubes can be changed dramatically with homogeneous transverse electric fields if the nanotubes have impurities or defects. The change of the resistance is predicted to range over more than two orders of magnitude with experimentally attainable electric fields. This novel property has its origin that backscattering of conduction electrons by impurities or defects in the nanotubes is strongly dependent on the strength and/or direction of the applied electric fields. We expect that this property will open a path to new device applications of metallic carbon nanotubes. Ref.) Young-Woo Son et al., Phys. Rev. Lett. 95, 216602 (2005).

  3. Functionalized carbon nanotubes for potential medicinal applications.

    PubMed

    Zhang, Yi; Bai, Yuhong; Yan, Bing

    2010-06-01

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

  4. Carbon Nanotubes and Chronic Granulomatous Disease

    PubMed Central

    Barna, Barbara P.; Judson, Marc A.; Thomassen, Mary Jane

    2014-01-01

    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. PMID:25525507

  5. Carbon nanotube filaments in household light bulbs

    NASA Astrophysics Data System (ADS)

    Wei, Jinquan; Zhu, Hongwei; Wu, Dehai; Wei, Bingqing

    2004-06-01

    Household light bulbs made from macroscopic single-walled and double-walled carbon nanotube filaments were fabricated and tested. The nanotube bulbs are found to possess several interesting features when compared to a conventional tungsten filament in safelight (36 V, 40 W), such as lower threshold voltage for light emission and higher brightness at high voltages. Electrically induced excited peaks at 407, 417, 655 nm were identified to be an intrinsic property of nanotubes and these peaks are observed to become stronger in the light emission spectra at high temperatures which cannot be explained easily with the concept of blackbody emission.

  6. Magnetic Susceptibility of Collapsed Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Ando, Tsuneya

    2017-02-01

    The orbital magnetic susceptibility is calculated in collapsed carbon nanotubes within an effective-mass scheme for two magnetic-field configurations, perpendicular and parallel to the flattened plane. The response is diamagnetic in both directions and is much larger for the perpendicular configuration, with some rare exceptions. In chiral nanotubes, calculated results show small and almost negligible effects of collapsing except for some modification due to change in the effective magnetic field. In nonchiral zigzag and armchair nanotubes, the susceptibility is strongly modified, depending on relative displacement of two layers in the flattened region.

  7. Extraordinary improvement of the graphitic structure of continuous carbon nanofibers templated with double wall carbon nanotubes.

    PubMed

    Papkov, Dimitry; Beese, Allison M; Goponenko, Alexander; Zou, Yan; Naraghi, Mohammad; Espinosa, Horacio D; Saha, Biswajit; Schatz, George C; Moravsky, Alexander; Loutfy, Raouf; Nguyen, Sonbinh T; Dzenis, Yuris

    2013-01-22

    Carbon nanotubes are being widely studied as a reinforcing element in high-performance composites and fibers at high volume fractions. However, problems with nanotube processing, alignment, and non-optimal stress transfer between the nanotubes and surrounding matrix have so far prevented full utilization of their superb mechanical properties in composites. Here, we present an alternative use of carbon nanotubes, at a very small concentration, as a templating agent for the formation of graphitic structure in fibers. Continuous carbon nanofibers (CNF) were manufactured by electrospinning from polyacrylonitrile (PAN) with 1.2% of double wall nanotubes (DWNT). Nanofibers were oxidized and carbonized at temperatures from 600 °C to 1850 °C. Structural analyses revealed significant improvements in graphitic structure and crystal orientation in the templated CNFs, with the largest improvements observed at lower carbonization temperatures. In situ pull-out experiments showed good interfacial bonding between the DWNT bundles and the surrounding templated carbon matrix. Molecular Dynamics (MD) simulations of templated carbonization confirmed oriented graphitic growth and provided insight into mechanisms of carbonization initiation. The obtained results indicate that global templating of the graphitic structure in fine CNFs can be achieved at very small concentrations of well-dispersed DWNTs. The outcomes reveal a simple and inexpensive route to manufacture continuous CNFs with improved structure and properties for a variety of mechanical and functional applications. The demonstrated improvement of graphitic order at low carbonization temperatures in the absence of stretch shows potential as a promising new manufacturing technology for next generation carbon fibers.

  8. Carbon nanotube polymer composites for photonic devices

    NASA Astrophysics Data System (ADS)

    Scardaci, V.; Rozhin, A. G.; Hennrich, F.; Milne, W. I.; Ferrari, A. C.

    2007-03-01

    We report the fabrication of high optical quality single wall carbon nanotube polyvinyl alcohol composites and their application in nanotube based photonic devices. These show a broad absorption of semiconductor tubes centred at ∼1.55 μm, the spectral range of interest for optical communications. The films are used as mode-lockers in an erbium doped fibre laser, achieving ∼700 fs mode-locked pulses. Raman spectroscopy shows no damage after a long time continuous laser operation.

  9. Does water dope carbon nanotubes?

    SciTech Connect

    Bell, Robert A.; Payne, Michael C.; Mostofi, Arash A.

    2014-10-28

    We calculate the long-range perturbation to the electronic charge density of carbon nanotubes (CNTs) as a result of the physisorption of a water molecule. We find that the dominant effect is a charge redistribution in the CNT due to polarisation caused by the dipole moment of the water molecule. The charge redistribution is found to occur over a length-scale greater than 30 Å, highlighting the need for large-scale simulations. By comparing our fully first-principles calculations to ones in which the perturbation due to a water molecule is treated using a classical electrostatic model, we estimate that the charge transfer between CNT and water is negligible (no more than 10{sup −4} e per water molecule). We therefore conclude that water does not significantly dope CNTs, a conclusion that is consistent with the poor alignment of the relevant energy levels of the water molecule and CNT. Previous calculations that suggest water n-dopes CNTs are likely due to the misinterpretation of Mulliken charge partitioning in small supercells.

  10. Carbon nanotube fiber terahertz polarizer

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

    Conventional, commercially available terahertz (THz) polarizers are made of uniformly and precisely spaced metallic wires. They are fragile and expensive, with performance characteristics highly reliant on wire diameters and spacings. Here, we report a simple and highly error-tolerant method for fabricating a freestanding THz polarizer with nearly ideal performance, reliant on the intrinsically one-dimensional character of conduction electrons in well-aligned carbon nanotubes (CNTs). The polarizer was constructed on a mechanical frame over which we manually wound acid-doped CNT fibers with ultrahigh electrical conductivity. We demonstrated that the polarizer has an extinction ratio of ˜-30 dB with a low insertion loss (<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.

  11. Elastomer Reinforced with Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    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.

  12. Thermal Transport in Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Christman, Jeremy; Moore, Andrew; Khatun, Mahfuza

    2011-10-01

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

  13. Different Technical Applications of Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

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

    2015-09-01

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

  14. Chemical reactions confined within carbon nanotubes.

    PubMed

    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.

  15. Different Technical Applications of Carbon Nanotubes.

    PubMed

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

    2015-12-01

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

  16. Measurement Challenges for Carbon Nanotube Material

    NASA Technical Reports Server (NTRS)

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

    2006-01-01

    The advances in large scale applications of carbon nanotubes demand a reliable supply of raw and processed materials. It is imperative to have a consistent quality control of these nanomaterials to distinguish material inconsistency from the modifications induced by processing of nanotubes for any application. NASA Johnson Space Center realized this need five years back and started a program to standardize the characterization methods. The JSC team conducted two workshops (2003 and 2005) in collaboration with NIST focusing on purity and dispersion measurement issues of carbon nanotubes [1]. In 2004, the NASA-JSC protocol was developed by combining analytical techniques of SEM, TEM, UV-VIS-NIR absorption, Raman, and TGA [2]. This protocol is routinely used by several researchers across the world as a first step in characterizing raw and purified carbon nanotubes. A suggested practice guide consisting of detailed chapters on TGA, Raman, electron microscopy and NIR absorption is in the final stages and is undergoing revisions with input from the nanotube community [3]. The possible addition of other techniques such as XPS, and ICP to the existing protocol will be presented. Recent activities at ANSI and ISO towards implementing these protocols as nanotube characterization standards will be discussed.

  17. Recent advances in molecular electronics based on carbon nanotubes.

    PubMed

    Bourgoin, Jean-Philippe; Campidelli, Stéphane; Chenevier, Pascale; Derycke, Vincent; Filoramo, Arianna; Goffman, Marcelo F

    2010-01-01

    Carbon nanotubes (CNTs) have exceptional physical properties that make them one of the most promising building blocks for future nanotechnologies. They may in particular play an important role in the development of innovative electronic devices in the fields of flexible electronics, ultra-high sensitivity sensors, high frequency electronics, opto-electronics, energy sources and nano-electromechanical systems (NEMS). Proofs of concept of several high performance devices already exist, usually at the single device level, but there remain many serious scientific issues to be solved before the viability of such routes can be evaluated. In particular, the main concern regards the controlled synthesis and positioning of nanotubes. In our opinion, truly innovative use of these nano-objects will come from: (i) the combination of some of their complementary physical properties, such as combining their electrical and mechanical properties, (ii) the combination of their properties with additional benefits coming from other molecules grafted on the nanotubes, and (iii) the use of chemically- or bio-directed self-assembly processes to allow the efficient combination of several devices into functional arrays or circuits. In this article, we outline the main issues concerning the development of carbon nanotubes based electronics applications and review our recent results in the field.

  18. Purification Procedures for Single-Wall Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Gorelik, Olga P.; Nikolaev, Pavel; Arepalli, Sivaram

    2001-01-01

    This report summarizes the comparison of a variety of procedures used to purify carbon nanotubes. Carbon nanotube material is produced by the arc process and laser oven process. Most of the procedures are tested using laser-grown, single-wall nanotube (SWNT) material. The material is characterized at each step of the purification procedures by using different techniques including scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), Raman, X-ray diffractometry (XRD), thermogravimetric analysis (TGA), nuclear magnetic resonance (NMR), and high-performance liquid chromatography (HPLC). The identified impurities are amorphous and graphitic carbon, catalyst particle aggregates, fullerenes, and hydrocarbons. Solvent extraction and low-temperature annealing are used to reduce the amount of volatile hydrocarbons and dissolve fullerenes. Metal catalysts and amorphous as well as graphitic carbon are oxidized by reflux in acids including HCl, HNO3 and HF and other oxidizers such as H2O2. High-temperature annealing in vacuum and in inert atmosphere helps to improve the quality of SWNTs by increasing crystallinity and reducing intercalation.

  19. Bulk Cutting of Carbon Nanotubes Using Electron Beam Irradiation

    NASA Technical Reports Server (NTRS)

    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.

  20. Carbon nanotubes for thermal interface materials in microelectronic packaging

    NASA Astrophysics Data System (ADS)

    Lin, Wei

    As the integration scale of transistors/devices in a chip/system keeps increasing, effective cooling has become more and more important in microelectronics. To address the thermal dissipation issue, one important solution is to develop thermal interface materials with higher performance. Carbon nanotubes, given their high intrinsic thermal and mechanical properties, and their high thermal and chemical stabilities, have received extensive attention from both academia and industry as a candidate for high-performance thermal interface materials. The thesis is devoted to addressing some challenges related to the potential application of carbon nanotubes as thermal interface materials in microelectronics. These challenges include: 1) controlled synthesis of vertically aligned carbon nanotubes on various bulk substrates via chemical vapor deposition and the fundamental understanding involved; 2) development of a scalable annealing process to improve the intrinsic properties of synthesized carbon nanotubes; 3) development of a state-of-art assembling process to effectively implement high-quality vertically aligned carbon nanotubes into a flip-chip assembly; 4) a reliable thermal measurement of intrinsic thermal transport property of vertically aligned carbon nanotube films; 5) improvement of interfacial thermal transport between carbon nanotubes and other materials. The major achievements are summarized. 1. Based on the fundamental understanding of catalytic chemical vapor deposition processes and the growth mechanism of carbon nanotube, fast synthesis of high-quality vertically aligned carbon nanotubes on various bulk substrates (e.g., copper, quartz, silicon, aluminum oxide, etc.) has been successfully achieved. The synthesis of vertically aligned carbon nanotubes on the bulk copper substrate by the thermal chemical vapor deposition process has set a world record. In order to functionalize the synthesized carbon nanotubes while maintaining their good vertical alignment

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

    PubMed

    Tardani, Franco; La Mesa, Camillo

    2014-09-01

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

  2. Formation of Carbon Nanotubes in a Microgravity Environment

    NASA Technical Reports Server (NTRS)

    Alford, J. M.; Mason, G. R.; Feikema, D. A.

    2001-01-01

    Even though nanotube science has become one of the worlds most rapidly advancing areas of research, very little is known about the processes involved in nanotube synthesis. To study the formation of carbon nanotubes in an environment unhindered by the buoyancy induced flows generated by the high temperatures necessary to vaporize carbon and grow nanotubes, we have designed a miniature carbon arc apparatus that can produce carbon nanotubes under microgravity conditions. During the first phase of this project, we designed, built, and successfully tested the mini carbon arc in both 1g and 2.2 sec drop tower microgravity conditions. We have demonstrated that microgravity can eliminate the strong convective flows from the carbon arc and we have successfully produced single-walled carbon nanotubes in microgravity. We believe that microgravity processing will allow us to better understand the nanotube formation process and eventually allow us to grow nanotubes that are superior to ground-based production.

  3. Mechanics of Carbon Nanotubes and their Polymer Composites

    NASA Technical Reports Server (NTRS)

    Wei, Chenyu; Cho, K. J.; Srivastava, Deepak; Tang, Harry (Technical Monitor)

    2002-01-01

    Contents include the folloving: carbon nanotube (CNT): structures, application of carbon nanotubes, simulation method, Elastic properties of carbon nanotubes, yield strain of CNT, yielding under tensile stress, yielding: strain-rate and temperature dependence, yield strain under tension, yielding at realistic conditions, nano fibers, polymer CNT composite, force field, density dependency on temperature, diffusion coefficients, young modulus, and conclusions.

  4. Proton Damage Effects on Carbon Nanotube Field-Effect Transistors

    DTIC Science & Technology

    2014-06-19

    PROTON DAMAGE EFFECTS ON CARBON NANOTUBE FIELD-EFFECT TRANSISTORS THESIS Evan R. Kemp, Ctr...United States. AFIT-ENP-T-14-J-39 PROTON DAMAGE EFFECTS ON CARBON NANOTUBE FIELD-EFFECT TRANSISTORS THESIS Presented to...PROTON DAMAGE EFFECTS ON CARBON NANOTUBE FIELD-EFFECT TRANSISTORS Evan R. Kemp, BS Ctr, USAF Approved: // Signed

  5. Carbon Nanotube/Graphene Supercapacitors Containing Manganese Oxide Nanoparticles

    DTIC Science & Technology

    2012-12-01

    Carbon Nanotube/Graphene Supercapacitors Containing Manganese Oxide Nanoparticles by Matthew Ervin, Vinay Raju, Mary Hendrickson, and...Laboratory Adelphi, MD 20783-1197 ARL-TR-6289 December 2012 Carbon Nanotube/Graphene Supercapacitors Containing Manganese Oxide...From - To) October 2011 to September 2012 4. TITLE AND SUBTITLE Carbon Nanotube/Graphene Supercapacitors Containing Manganese Oxide Nanoparticles

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

    PubMed

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

    2013-10-10

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

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

    DOEpatents

    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.

  8. Electrical, Mechanical, and Capacity Percolation Leads to High-Performance MoS2/Nanotube Composite Lithium Ion Battery Electrodes.

    PubMed

    Liu, Yuping; He, Xiaoyun; Hanlon, Damien; Harvey, Andrew; Khan, Umar; Li, Yanguang; Coleman, Jonathan N

    2016-06-28

    Advances in lithium ion batteries would facilitate technological developments in areas from electrical vehicles to mobile communications. While two-dimensional systems like MoS2 are promising electrode materials due to their potentially high capacity, their poor rate capability and low cycle stability are severe handicaps. Here, we study the electrical, mechanical, and lithium storage properties of solution-processed MoS2/carbon nanotube anodes. Nanotube addition gives up to 10(10)-fold and 40-fold increases in electrical conductivity and mechanical toughness, respectively. The increased conductivity results in up to a 100× capacity enhancement to ∼1200 mAh/g (∼3000 mAh/cm(3)) at 0.1 A/g, while the improved toughness significantly boosts cycle stability. Composites with 20 wt % nanotubes combine high reversible capacity with excellent cycling stability (e.g., ∼950 mAh/g after 500 cycles at 2 A/g) and high rate capability (∼600 mAh/g at 20 A/g). The conductivity, toughness, and capacity scale with nanotube content according to percolation theory, while the stability increases sharply at the mechanical percolation threshold. We believe that the improvements in conductivity and toughness obtained after addition of nanotubes can be transferred to other electrode materials, such as silicon nanoparticles.

  9. Single Nanotube Spectral Imaging To Determine Molar Concentrations of Isolated Carbon Nanotube Species.

    PubMed

    Galassi, Thomas V; Jena, Prakrit V; Roxbury, Daniel; Heller, Daniel A

    2017-01-17

    Electronic and biological applications of carbon nanotubes can be highly dependent on the species (chirality) of nanotube, purity, and concentration. Existing bulk methods, such as absorbance spectroscopy, can quantify sp(2) carbon based on spectral bands, but nanotube length distribution, defects, and carbonaceous impurities can complicate quantification of individual particles. We present a general method to relate the optical density of a photoluminescent nanotube sample to the number of individual nanotubes. By acquiring 3-dimensional images of nanotubes embedded in a gel matrix with a reducing environment, we quantified all emissive nanotubes in a volume. Via spectral imaging, we assessed structural impurities and precisely determined molar concentrations of the (8,6) and (9,4) nanotube species. We developed an approach to obtain the molarity of any structurally enriched semiconducting single-walled carbon nanotube preparation on a per-nanotube basis.

  10. Carbon nanotubes in neuroregeneration and repair.

    PubMed

    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.

  11. Carbon Nanotube Bolometer for Absolute FTIR Spectroscopy

    NASA Astrophysics Data System (ADS)

    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.

  12. A review on protein functionalized carbon nanotubes.

    PubMed

    Nagaraju, Kathyayini; Reddy, Roopa; Reddy, Narendra

    2015-12-18

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

  13. Boron-Filled Hybrid Carbon Nanotubes.

    PubMed

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

    2016-07-27

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

  14. Boron-Filled Hybrid Carbon Nanotubes

    PubMed Central

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

    2016-01-01

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

  15. Piezoresistive effect in carbon nanotube fibers.

    PubMed

    Lekawa-Raus, Agnieszka; Koziol, Krzysztof K K; Windle, Alan H

    2014-11-25

    The complex structure of the macroscopic assemblies of carbon nanotubes and variable intrinsic piezoresistivity of nanotubes themselves lead to highly interesting piezoresistive performance of this new type of conductive material. Here, we present an in-depth study of the piezoresistive effect in carbon nanotube fibers, i.e., yarnlike assemblies made purely of aligned carbon nanotubes, which are expected to find applications as electrical and electronic materials. The resistivity changes of carbon nanotube fibers were measured on initial loading, through the elastic/plastic transition, on cyclic loading and on stress relaxation. The various regimes of stress/strain behavior were modeled using a standard linear solid model, which was modified with an additional element in series to account for the observed creep behavior. On the basis of the experimental and modeling results, the origin of piezoresistivity is discussed. An additional effect on the resistivity was found as the fiber was held under load which led to observations of the effect of humidity and the associated water adsorption level on the resistivity. We show that the equilibrium uptake of moisture leads to the decrease in gauge factor of the fiber decrease, i.e., the reduction in the sensitivity of fiber resistivity to loading.

  16. Carbon Nanotubes Synthesis Through Gamma Radiation

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

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

  17. Transport Through Carbon Nanotube Wires

    NASA Technical Reports Server (NTRS)

    Anantram, M. P.; Yan, Jerry (Technical Monitor)

    2000-01-01

    This viewgraph presentation gives an overview of the the current carrying capacity of nanotube wires. Information is given on the motivation for the research, models and assumptions, Bragg reflection and Zener tunneling effects, and the influence of defects. Results show that dI/dv versus V does not increase in a manner commensurate with the increase in the number of subbands; in small diameter nanotubes, Zener tunneling is ineffective; Zener tunneling contributes to current with increase in nanotube diameter; and the increase in dI/dV with bias is much smaller than the increase in the number of subbands.

  18. Single wall carbon nanotubes: Separation and applications to biosensors

    NASA Astrophysics Data System (ADS)

    Kim, Sang Nyon

    Single wall carbon nanotubes uniquely exhibit one-dimensional quantum confined properties by being either semiconducting (sem-) or metallic (met-) depending on their atomic arrangements. The stochastic nature of SWNT growth renders met-:sem- ratio being 1:2 and diameter range being distributed in 0.4-2nm with a close-packed bundle configuration. For many high-performance devices using SWNTs, acquiring well-separated and/or isolated single-diameter, metallicity and/or chirality nanotubes is greatly in demand. Recently, the bulk separation and/or enrichment of single wall carbon nanotubes (SWNTs) according to type (or otherwise termed "metallicity") and diameter (dt) has become possible. This thesis presents a route to probe mechanisms in diameter and metallicity dependent separation of SWNTs. A systematic analysis tool, that enables the quantitative examination of resonance Raman spectra, is established from nanotube samples that have been separated according to metallicity and d t via an octadecylamine mediated protocol. This protocol uses the relative changes in the integrated intensities of the radial-breathing mode region for the quantitative evaluation. By further establishing the physicochemical properties of charge-stabilized SWNT dispersions in polar aprotic media (i.e. N,N-dimethylformide) a more detailed description of the underlying separation mechanism is given. Here, I use resonance Raman spectroscopy (RRS) as a tool to probe SWNT redox chemistry. The Gibbs free energy, modeled by calculating the charge-loss from the (n,m)-dependent integrated density of states across the corresponding jump in the redox potential, is utilized to support the separation mechanism. Additionally, the evaluation of SWNT forest platforms for amperometric protein immunoassays is presented. Horseradish peroxidase is used as the label and the sensing signals are acquired from electrochemical reduction of hydrogen peroxide. Specific studies on human serum albumin and prostate

  19. Carbon Nanotube Spaceframes for Low-Density Aerospace Materials

    DTIC Science & Technology

    2012-01-26

    Functionalization Methods Chemically sculpting carbon nanotubes into nano-objects of the type needed for synthesizing CNT spaceframe materials require two...distinct functionalization chemistries that produce distinct functional structures at the ends of the nanotubes and on the sidewalls of the nanotubes ...which are applied to the nanotubes . In this project, oxidative etching techniques were explored for end selective functionalization . Selective

  20. Carbon Nanotube-Enhanced Carbon-Phenenolic Ablator Material

    NASA Technical Reports Server (NTRS)

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

    2006-01-01

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

  1. A carbon nanotube optical rectenna.

    PubMed

    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.

  2. A carbon nanotube optical rectenna

    NASA Astrophysics Data System (ADS)

    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.

  3. Laser ablative synthesis of carbon nanotubes

    DOEpatents

    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.

  4. High Performance Bulk Thermoelectric Materials

    SciTech Connect

    Ren, Zhifeng

    2013-03-31

    Over 13 plus years, we have carried out research on electron pairing symmetry of superconductors, growth and their field emission property studies on carbon nanotubes and semiconducting nanowires, high performance thermoelectric materials and other interesting materials. As a result of the research, we have published 104 papers, have educated six undergraduate students, twenty graduate students, nine postdocs, nine visitors, and one technician.

  5. A tunable carbon nanotube electromechanical oscillator

    NASA Astrophysics Data System (ADS)

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

    2004-09-01

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

  6. The Use of Plasma Vortexes in Creating Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Leith, Alexander; Alexander Leith Collaboration

    2016-03-01

    Carbon nanotubes have been created in a variety of ways such as arc discharge, laser ablation, and chemical vapor deposition (CVD). Each of these techniques has been proven to produce carbon nanotubes in small quantities in a lab setting. This is the problem that we have been addressing. Over the course of 16 months, we have been working on a new method of carbon nanotube production that is based around fluid dynamics and plasma. We have created the basic components to test this new way to produce carbon nanotubes. This research will ideally provide a new avenue for carbon nanotube production. Worked with Dr. Randal Tagg of the University of Colorado Denver.

  7. Multipurpose organically modified carbon nanotubes: from functionalization to nanotube composites.

    PubMed

    Georgakilas, Vasilios; Bourlinos, Athanasios; Gournis, Dimitrios; Tsoufis, Theodoros; Trapalis, Christos; Mateo-Alonso, Aurelio; Prato, Maurizio

    2008-07-09

    We show that covalent functionalization of carbon nanotubes (CNTs) via 1,3-dipolar cycloaddition is a powerful method for enhancing the ability to process CNTs and facilitating the preparation of hybrid composites, which is achieved solely by mixing. CNTs were functionalized with phenol groups, providing stable dispersions in a range of polar solvents, including water. Additionally, the functionalized CNTs could easily be combined with polymers and layered aluminosilicate clay minerals to give homogeneous, coherent, transparent CNT thin films and gels.

  8. Computational Nanomechanics of Carbon Nanotubes and Composites

    NASA Technical Reports Server (NTRS)

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

    2002-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2017-02-01

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

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

    PubMed

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

    2017-02-17

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

  11. Flexible microdevices based on carbon nanotubes

    NASA Astrophysics Data System (ADS)

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

    2006-12-01

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

  12. Improved Method of Purifying Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Delzeit, Lance D.

    2004-01-01

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

  13. Carbon nanotubes as optical biomedical sensors.

    PubMed

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

    2013-12-01

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

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

    SciTech Connect

    2010-03-01

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

  15. Coupling of carbon and peptide nanotubes.

    PubMed

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

    2014-02-12

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

  16. N- and O-doped carbonaceous nanotubes from polypyrrole for potential application in high-performance capacitance

    NASA Astrophysics Data System (ADS)

    Guo, Chengxin; Li, Na; Ji, Liangliang; Li, Yaowen; Yang, Xiaoming; Lu, Yun; Tu, Yingfeng

    2014-02-01

    By the reactive self-degraded template-directed synthesis and further carbonization, N- and O-doped carbonaceous nanotubes from conducting polymer (polypyrrole) precursor have been prepared. After being chemically activated by KOH, specially, with the weight ratio of KOH to polypyrrole nanotubes of 2 and 4, two samples of activated carbonaceous polypyrrole nanotubes (ACPN-2 and ACPN-4) with an uncapped morphology were obtained. The ACPN-4 possesses high heteroatom content (14.85%) and specific surface area (1226 m2 g-1), and exhibits a reversible capacitance of 470 F g-1 at the current density of 0.2 A g-1, and 280 F g-1 even at a higher current density of 10 A g-1. Moreover, these nanotubular structured materials have also shown excellent cycling performance with no capacitance loss over 10,000 cycles. Furthermore, these carbonaceous nanotubes achieved a high CO2 adsorption uptake of 3.9 mmol g-1 at 273 K and 2.5 mmol g-1 at 298 K.

  17. CARBON NANOTUBES IN MICROWAVE ENVIRONMENT-IGNITION AND RECONSTRUCTION

    EPA Science Inventory

    The unusual property of single-walled carbon nanotubes (SWNT), multi-wall (MWNT) nanotubes and Buckminsterfullerene (C-60) is observed upon exposure to microwave-assisted ignition. Carbon nanotubes known for a range of mechanical and electronic properties because of their unique...

  18. Collective mechanochemical growth of carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Bedewy, Mostafa M. K. M. A.

    Hierarchically ordered carbon nanotubes (CNTs) are promising for integration in high-performance structural composites, electrical interconnects, thermal interfaces, and filtration membranes. These and other applications require CNTs that are monodisperse, well aligned, and densely packed. Moreover, because more than 1 billion CNTs per square centimeter grow simultaneously in a typical chemical vapor deposition (CVD) process, understanding the collective chemical and mechanical effects of growth is key to engineering the properties of CNT-based materials. This dissertation presents tailored synthesis processes, characterization techniques, and mathematical models that enable improved control of the morphology of as-grown CNT "forests.". First, a comprehensive characterization methodology, combining synchrotron X-ray scattering and attenuation with real-time height kinetics, enabled mapping the spatiotemporal evolution of CNT diameter distribution, alignment and density. By this method, the forest mass kinetics were measured and found to follow the S-shaped Gompertz curve of population growth. Dividing a forest into subpopulations revealed size-dependent activation-deactivation competition. Additionally, in situ transmission electron microscopy (TEM) showed that the kinetics of CNT nucleation are S-shaped. Based on these findings, a collective growth model is proposed, wherein randomly oriented CNTs first nucleate then self-organize and lift-off during a crowding stage, followed by a density decay stage until self-termination when the density drops below the self-supporting threshold. Next, further X-ray data analysis enabled modeling the mechanics of entangled CNTs and proved that mechanical coupling is not only responsible for the self-organization into the aligned morphology, but is also an important limiting mechanism as significant forces ensue from diameter-dependent CNT growth rates. A custom-built CVD system was used for mechanical manipulation of growing

  19. Deconvoluting hepatic processing of carbon nanotubes

    PubMed Central

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

    2016-01-01

    Single-wall carbon nanotubes present unique opportunities for drug delivery, but have not advanced into the clinic. Differential nanotube accretion and clearance from critical organs have been observed, but the mechanism not fully elucidated. The liver has a complex cellular composition that regulates a range of metabolic functions and coincidently accumulates most particulate drugs. Here we provide the unexpected details of hepatic processing of covalently functionalized nanotubes including receptor-mediated endocytosis, cellular trafficking and biliary elimination. Ammonium-functionalized fibrillar nanocarbon is found to preferentially localize in the fenestrated sinusoidal endothelium of the liver but not resident macrophages. Stabilin receptors mediate the endocytic clearance of nanotubes. Biocompatibility is evidenced by the absence of cell death and no immune cell infiltration. Towards clinical application of this platform, nanotubes were evaluated for the first time in non-human primates. The pharmacologic profile in cynomolgus monkeys is equivalent to what was reported in mice and suggests that nanotubes should behave similarly in humans. PMID:27468684

  20. Synthesis of Carbon Nanotube (CNT) Composite Membranes

    PubMed Central

    Altalhi, Tariq; Ginic-Markovic, Milena; Han, Ninghui; Clarke, Stephen; Losic, Dusan

    2011-01-01

    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. PMID:24957494

  1. Carbon nanotubes as supports for inulinase immobilization.

    PubMed

    Garlet, Tais B; Weber, Caroline T; Klaic, Rodrigo; Foletto, Edson L; Jahn, Sergio L; Mazutti, Marcio A; Kuhn, Raquel C

    2014-09-15

    The commercial inulinase obtained from Aspergillus niger was non-covalently immobilized on multiwalled carbon nanotubes (MWNT-COOH). The immobilization conditions for the carbon nanotubes were defined by the central composite rotational design (CCRD). The effects of enzyme concentration (0.8%-1.7% v/v) and adsorbent:adsorbate ratio (1:460-1:175) on the enzyme immobilization were studied. The adsorbent:adsorbate ratio variable has positive effect and the enzyme concentration has a negative effect on the inulinase immobilization (U/g) response at the 90% significance level. These results show that the lower the enzyme concentration and the higher the adsorbent:adsorbate ratio, better is the immobilization. According to the results, it is possible to observe that the carbon nanotubes present an effective inulinase adsorption. Fast adsorption in about six minutes and a loading capacity of 51,047 U/g support using a 1.3% (v/v) inulinase concentration and a 1:460 adsorbent:adsorbate ratio was observed. The effects of temperature on the immobilized enzyme activity were evaluated, showing better activity at 50 °C. The immobilized enzyme maintained 100% of its activity during five weeks at room temperature. The immobilization strategy with MWNT-COOH was defined by the experimental design, showing that inulinase immobilization is a promising biotechnological application of carbon nanotubes.

  2. Conductance of AFM Deformed Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

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

    2002-01-01

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

  3. Photothermal effects of immunologically modified carbon nanotubes

    NASA Astrophysics Data System (ADS)

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

    2013-02-01

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

  4. In-line manufacture of carbon nanotubes

    SciTech Connect

    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.

  5. Chemistry of Carbon Nanotubes for Everyone

    ERIC Educational Resources Information Center

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

    2012-01-01

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

  6. Carbon Nanotube Based Electrochemical Supercapacitor Electrodes

    DTIC Science & Technology

    2009-05-30

    solution properties and electrospinning conditions, one can produce particles or fibers with controlled morphology for specific applications...Poly( acrylonitrile) (PAN) based nanofibers were electrospun with controlled diameter . A sacrificial polymer, poly(styrene-co-acrylonitrile) (SAN...has been used to control porosity. Carbon nanotubes (CNT) have been used to increase electrode conductivity and hence power density. The diameter of

  7. Probing Photosensitization by Functionalized Carbon Nanotubes.

    PubMed

    Chen, Chia-Ying; Zepp, Richard G

    2015-12-01

    Carbon nanotubes (CNTs) photosensitize the production of reactive oxygen species that may damage organisms by biomembrane oxidation or mediate environmental transformations of CNTs. Photosensitization by derivatized carbon nanotubes from various synthetic methods, and thus with different intrinsic characteristics (e.g., diameter and electronic properties), has been investigated under environmentally relevant aquatic conditions. We used the CNT-sensitized photoisomerization of sorbic acid ((2E,4E)-hexa-2,4-dienoic acid) and singlet oxygen formation to quantify the triplet states ((3)CNT*) formed upon irradiation of selected single-walled carbon nanotubes (SWCNTs) and multiwalled carbon nanotubes (MWCNTs). The CNTs used in our studies were derivatized by carboxyl groups to facilitate their dispersion in water. Results indicate that high-defect-density (thus well-stabilized), small-diameter, and semiconducting-rich CNTs have higher-measured excited triplet state formation and therefore singlet oxygen ((1)O2) yield. Derivatized SWCNTs were significantly more photoreactive than derivatized MWCNTs. Moreover, addition of sodium chloride resulted in increased aggregation and small increases in (1)O2 production of CNTs. The most photoreactive CNTs exhibited comparable photoreactivity (in terms of (3)CNT* formation and (1)O2 yield) to reference natural organic matter (NOM) under sunlight irradiation with the same mass-based concentration. Selected reference NOM could therefore be useful in evaluating environmental photoreactivity or intended antibacterial applications of CNTs.

  8. Sulfur-Immobilized, Activated Porous Carbon Nanotube Composite Based Cathodes for Lithium-Sulfur Batteries.

    PubMed

    Lee, Jun Seop; Jun, Jaemoon; Jang, Jyongsik; Manthiram, Arumugam

    2017-03-01

    Activated highly porous carbon nanotubes are synthesized with a facile dual-nozzle co-electrospinning and a redox process to apply the framework of a sulfur-immobilized composite as a high-performance cathode in lithium-sulfur batteries.

  9. Heat Transport in Liquid Polyester Resin with Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Vales-Pinzón, C.; Quiñones-Weiss, G.; Alvarado-Gil, J. J.; Medina-Esquivel, R. A.

    2015-11-01

    Carbon nanotubes represent one of the most important materials in nanoscience and nanotechnology, due to their outstanding structural, mechanical, electrical, and thermal properties. It has been shown that when incorporated in a polymeric matrix, carbon nanotubes can improve its physical properties. In this work, thermal-diffusivity measurements of composite materials, prepared by mixing carbon nanotubes in liquid polyester resin, were performed by means of the thermal-wave resonant cavity. The results show an increase of the thermal diffusivity when the volume fraction of carbon nanotubes grows. It is also shown that this increase depends strongly on the diameter of the nanotubes.

  10. Electromechanical transducers based on single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Stampfer, C.; Jungen, A.; Helbling, T.; Durrer, L.; Hierold, C.

    2008-08-01

    Carbon Nanotubes are intensively studied as a new functional material for nanoelectronics and nano electromechanical systems, including nanosensor devices. Single-walled carbon nanotubes (SWNTs) show unique mechanical and electromechanical properties and they change electronic properties by interacting with the environment (this can be e.g. used for chemical and biochemical sensing). Therefore nanotubes are very promising candidates for active elements in future nanoscaled transducers. Concepts for carbon nanotube sensors for mechanical and chemical detection schemes are presented. We focus on single-walled carbon nanotubes as natural macro molecular functional structures with an option for low scale integration in micro and nano electromechanical systems (MEMS and NEMS).

  11. Three dimensional carbon-nanotube polymers.

    PubMed

    Zhao, Zhisheng; Xu, Bo; Wang, Li-Min; Zhou, Xiang-Feng; He, Julong; Liu, Zhongyuan; Wang, Hui-Tian; Tian, Yongjun

    2011-09-27

    Eight fascinating sp(2)- and sp(3)-hybridized carbon allotropes have been uncovered using a newly developed ab initio particle-swarm optimization methodology for crystal structure prediction. These crystalline allotropes can be viewed respectively as three-dimensional (3D) polymers of (4,0), (5,0), (7,0), (8,0), (9,0), (3,3), (4,4), and (6,6) carbon nanotubes, termed 3D-(n, 0) or 3D-(n, n) carbons. The ground-state energy calculations show that the carbons all have lower energies than C(60) fullerene, and some are energetically more stable than the van der Waals packing configurations of their nanotube parents. Owing to their unique configurations, they have distinctive electronic properties, high Young's moduli, high tensile strength, ultrahigh hardness, good ductility, and low density, and may be potentially applied to a variety of needs.

  12. Isotope Engineering of Carbon Nanotube Systems

    NASA Astrophysics Data System (ADS)

    Simon, F.; Kramberger, Ch.; Pfeiffer, R.; Kuzmany, H.; Zólyomi, V.; Kürti, J.; Singer, P. M.; Alloul, H.

    2005-06-01

    The synthesis of a unique isotope engineered system, double-wall carbon nanotubes with natural carbon outer and highly 13C enriched inner walls, is reported from isotope enriched fullerenes encapsulated in single-wall carbon nanotubes (SWCNTs). The material allows the observation of the D line of the highly defect-free inner tubes that can be related to a curvature induced enhancement of the electron-phonon coupling. Ab initio calculations explain the inhomogeneous broadening of inner tube Raman modes due to the distribution of different isotopes. Nuclear magnetic resonance shows a significant contrast of the isotope enriched inner SWCNTs compared to other carbon phases and provides a macroscopic measure of the inner tube mass content. The high curvature of the small diameter inner tubes manifests in an increased distribution of the chemical shift tensor components.

  13. Nanotubes.

    PubMed

    Rao, C N; Satishkumar, B C; Govindaraj, A; Nath, M

    2001-02-16

    Carbon nanotubes were discovered soon after the successful laboratory synthesis of fullerenes. Since their discovery in 1991, there has been intensive research activity in the area of carbon nanotubes, not only because of their fascinating structural features and properties, but also because of their potential technological applications. There is increasing experimental evidence to show that carbon nanotubes may find use in nanoelectronic devices, displays, and in hydrogen storage. In this article, we discuss various important aspects related to the synthesis, structure, characterization, and mechanism of formation of multi-walled and single-walled carbon nanotubes, followed by a presentation of the important electronic, mechanical, hydrogen storage, and other properties of the nanotubes. Doping, as well as other chemical manipulations with boron and nitrogen, bring about significant changes in the properties of the nanotubes. Carbon nanotubes also serve as useful templates to make other nanostructures. Layered metal chalcogenides, boron nitride, and other materials form nanotubes and provide considerable scope for study.

  14. Carbon Nanotubes: From Symmetry to Applications

    NASA Astrophysics Data System (ADS)

    Damnjanović, M.

    In this chapter, we show how the concept of symmetry gives theoretical explanation of the properties, which made carbon nanotubes (NTs) one of the most interesting materials of nanotechnology. First, in Sect. 3.1, we consider basic facts on single-wall carbon nanotubes (SWCNTs), including their configuration and symmetry. Then, we discuss double-wall nanotubes.Next, Sect. 3.2 is devoted to elementary symmetry-based physical properties. More precisely, we explain the energy spectrum of electrons and phonons, showing that as the consequence of the symmetry, energies must be arranged in the so-called bands. Elementary properties of these band structures may be a priory discussed, yielding easily famous conducting law, showing strong dependence of conductivity on the type of nanotube. Conserved quantum numbers enable us to extract selection rules for various physical processes. This way, radial breathing mode appears to be very important for the characterization of the samples by Raman spectroscopy. Also, optical properties are derived.Finally, in Sect. 3.3, mutual interaction between the walls of double-wall nanotubes is discussed. It is explained why this interaction is very weak, which is used to propose nanomachines with almost superslippery parts.

  15. Effective reinforcement in carbon nanotube-polymer composites.

    PubMed

    Wang, W; Ciselli, P; Kuznetsov, E; Peijs, T; Barber, A H

    2008-05-13

    Carbon nanotubes have mechanical properties that are far in excess of conventional fibrous materials used in engineering polymer composites. Effective reinforcement of polymers using carbon nanotubes is difficult due to poor dispersion and alignment of the nanotubes along the same axis as the applied force during composite loading. This paper reviews the mechanical properties of carbon nanotubes and their polymer composites to highlight how many previously prepared composites do not effectively use the excellent mechanical behaviour of the reinforcement. Nanomechanical tests using atomic force microscopy are carried out on simple uniaxially aligned carbon nanotube-reinforced polyvinyl alcohol (PVA) fibres prepared using electrospinning processes. Dispersion of the carbon nanotubes within the polymer is achieved using a surfactant. Young's modulus of these simple composites is shown to approach theoretically predicted values, indicating that the carbon nanotubes are effective reinforcements. However, the use of dispersant is also shown to lower Young's modulus of the electrospun PVA fibres.

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

    PubMed

    Hanus, Monica J; Harris, Andrew T

    2010-04-01

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

  17. Carbon nanotube oscillators for applications as nanothermometers

    NASA Astrophysics Data System (ADS)

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

    2010-10-01

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

  18. Growth of copper oxide nanocrystals in metallic nanotubes for high performance battery anodes.

    PubMed

    Zhao, Yuxin; Mu, Shanjun; Sun, Wanfu; Liu, Quanzhen; Li, Yanpeng; Yan, Zifeng; Huo, Ziyang; Liang, Wenjie

    2016-12-08

    A rational integration of 1D metallic nanotubes and oxide nanoparticles has been demonstrated as a viable strategy for the production of both highly stable and efficient anodes for lithium ion batteries. We encapsulated copper oxide (CuO) nanoparticles in ultra-long metallic copper nanotubes with engineered interspaces, and explored their electrochemical properties. Such a hierarchical architecture provides three important features: (i) a continuous nanoscale metallic Cu shell to minimize electronic/ionic transmitting impedance; (ii) a unique quasi-one-dimensional structure with a large aspect ratio to reduce self-aggregation; (iii) free space for volume expansion of CuO nanoparticles and stable solid-electrolyte interphase (SEI) formation. The anode materials with such hierarchical structures have high specific capacity (around 600 mA h g(-1) at a current density of 0.1 A g(-1)), excellent cycling stability (over 94% capacity retention after 200 cycles) and superb reversible capacity of 175 mA h g(-1) at a high charging rate of 15 A g(-1).

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

    NASA Astrophysics Data System (ADS)

    Yzeiri, Irena; Patra, Niladri; Král, Petr

    2014-03-01

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

  20. A complete carbon counter electrode for high performance quasi solid state dye sensitized solar cell

    NASA Astrophysics Data System (ADS)

    Arbab, Alvira Ayoub; Peerzada, Mazhar Hussain; Sahito, Iftikhar Ali; Jeong, Sung Hoon

    2017-03-01

    The proposed research describes the design and fabrication of a quasi-solid state dye sensitized solar cells (Q-DSSCs) with a complete carbon based counter electrode (CC-CE) and gel infused membrane electrolyte. For CE, the platinized fluorinated tin oxide glass (Pt/FTO) was replaced by the soft cationic functioned multiwall carbon nanotubes (SCF-MWCNT) catalytic layer coated on woven carbon fiber fabric (CFF) prepared on handloom by interlacing of carbon filament tapes. SCF-MWCNT were synthesized by functionalization of cationised lipase from Candida Ragusa. Cationised enzyme solution was prepared at pH ∼3 by using acetic acid. The cationic enzyme functionalization of MWCNT causes the minimum damage to the tubular morphology and assist in fast anchoring of negative iodide ions present in membrane electrolyte. The high electrocatalytic activity and low charge transfer resistance (RCT = 2.12 Ω) of our proposed system of CC-CE shows that the woven CFF coated with cationised lipase treated carbon nanotubes enriched with positive surface ions. The Q-DSSCs fabricated with CC-CE and 5 wt% PEO gel infused PVDF-HFP membrane electrolyte exhibit power conversion efficiency of 8.90% under masking. Our suggested low cost and highly efficient system of CC-CE helps the proposed quasi-solid state DSSCs structure to stand out as sustainable next generation solar cells.

  1. Carbon nanotubes on a spider silk scaffold

    PubMed Central

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

    2013-01-01

    Understanding the compatibility between spider silk and conducting materials is essential to advance the use of spider silk in electronic applications. Spider silk is tough, but becomes soft when exposed to water. Here we report a strong affinity of amine-functionalised multi-walled carbon nanotubes for spider silk, with coating assisted by a water and mechanical shear method. The nanotubes adhere uniformly and bond to the silk fibre surface to produce tough, custom-shaped, flexible and electrically conducting fibres after drying and contraction. The conductivity of coated silk fibres is reversibly sensitive to strain and humidity, leading to proof-of-concept sensor and actuator demonstrations. PMID:24022336

  2. Atomic nanotube welders: boron interstitials triggering connections in double-walled carbon nanotubes.

    PubMed

    Endo, Morinobu; Muramatsu, Hiroyuki; Hayashi, Takuya; Kim, Yoong-Ahm; Van Lier, Gregory; Charlier, Jean-Christophe; Terrones, Humberto; Terrones, Mauricio; Dresselhaus, Mildred S

    2005-06-01

    Here we demonstrate that the incorporation of boron (B) atoms between double-walled carbon nanotubes (DWNTs) during thermal annealing (1400-1600 degrees C) results in covalent nanotube "Y" junctions, DWNT coalescence, and the formation of flattened multiwalled carbon nanotubes (MWNTs). These processes occur via the merging of adjacent tubes, which is triggered by B interstitial atoms. We observe that B atom interstitials between DWNTs are responsible for the rapid establishment of covalent connections between neighboring tubes (polymerization), thereby resulting in the fast annealing of the carbon cylinders with B atoms embedded in the newly created carbon nanotube network. Once B is in the lattice, tube faceting (polygonization) starts to occur, and the electronic properties are expected to change dramatically. Therefore, B atoms indeed act as atomic nanotube fusers (or welders), and this process could now be used in assembling novel electronic nanotube devices, nanotube networks, carbon nanofoams and heterojunctions exhibiting p-type electronic properties.

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

    DTIC Science & Technology

    2009-02-01

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

  4. Functionalization of vertically aligned carbon nanotubes

    PubMed Central

    Snyders, Rony; Colomer, Jean-François

    2013-01-01

    Summary 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. PMID:23504581

  5. Transmission Through Carbon Nanotubes with Polyhedral Caps

    NASA Technical Reports Server (NTRS)

    Anantram, M. P.; Govindan, T. R.

    1999-01-01

    We study electron transport between capped carbon nanotubes and a substrate, and relate this transport to the local density of states in the cap. Our results show that that the transmission probability mimics the behavior of the density of states at all energies except those that correspond to localized states. For a capped carbon nanotube that is not connected to a substrate, the localized states do not couple to the coexisting continuum states. However, close proximity of a substrate causes hybridization between these states. As a result, new transmission paths open from substrate states to nanotube continuum states via the localized states in the cap. We show that the interference between various paths gives rise to transmission antiresonances with the minimum equal to zero at the energy of the localized state. The presence of defects in the tube places close to the cap transforms antiresonances into resonances. Depending on the spatial position of defects, these resonant states are capable of carrying a large current. The results of this paper are of relevance to carbon nanotube based studies on molecular electronics and probe tip applications.

  6. Adsorption of Gases on Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Mbaye, Mamadou Thiao

    2014-01-01

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

  7. Mechanical properties of functionalized carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Zhang, Z. Q.; Liu, B.; Chen, Y. L.; Jiang, H.; Hwang, K. C.; Huang, Y.

    2008-10-01

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

  8. Diffusion through Carbon Nanotube Semipermeable membranes

    SciTech Connect

    Bakajin, O

    2006-02-13

    The goal of this project is to measure transport through CNTs and study effects of confinement at molecular scale. This work is motivated by several simulation papers in high profile journals that predict significantly higher transport rates of gases and liquids through carbon nanotubes as compared with similarly-sized nanomaterials (e.g. zeolites). The predictions are based on the effects of confinement, atomically smooth pore walls and high pore density. Our work will provide the first measurements that would compare to and hopefully validate the simulations. Gas flux is predicted to be >1000X greater for SWNTs versus zeolitesi. A high flux of 6-30 H2O/NT/ns {approx} 8-40 L/min for a 1cm{sup 2} membrane is also predicted. Neutron diffraction measurements indicate existence of a 1D water chain within a cylindrical ice sheet inside carbon nanotubes, which is consistent with the predictions of the simulation. The enabling experimental platform that we are developing is a semipermeable membrane made out of vertically aligned carbon nanotubes with gaps between nanotubes filled so that the transport occurs through the nanotubes. The major challenges of this project included: (1) Growth of CNTs in the suitable vertically aligned configuration, especially the single wall carbon nanotubes; (2) Development of a process for void-free filling gaps between CNTs; and (3) Design of the experiments that will probe the small amounts of analyte that go through. Knowledge of the behavior of water upon nanometer-scale confinement is key to understanding many biological processes. For example, the protein folding process is believed to involve water confined in a hydrophobic environment. In transmembrane proteins such as aquaporins, water transport occurs under similar conditions. And in fields as far removed as oil recovery and catalysis, an understanding of the nanoscale molecular transport occurring within the nanomaterials used (e.g. zeolites) is the key to process optimization

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

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

    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.

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

    PubMed

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

    2016-04-29

    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.

  11. Half-metallic zigzag carbon nanotube dots.

    PubMed

    Hod, Oded; Scuseria, Gustavo E

    2008-11-25

    A comprehensive first-principles theoretical study of the electronic properties and half-metallic nature of finite zigzag carbon nanotubes is presented. Unlike previous reports, we find that all nanotubes studied present a spin-polarized ground state, where opposite spins are localized at the two zigzag edges in a long-range antiferromagnetic-type configuration. Relative stability analysis of the different spin states indicates that, for the shorter segments, spin-ordering should be present even at room temperature. The energy gap between the highest occupied and the lowest unoccupied molecular orbitals of the finite systems is found to be inversely proportional to the nanotube's segment lengths, suggesting a route to control their electronic properties. Similar to the case of zigzag graphene nanoribbons, half-metallic behavior is obtained under the influence of an external axial electric field.

  12. Template-Free Synthesis of Ruthenium Oxide Nanotubes for High-Performance Electrochemical Capacitors.

    PubMed

    Kim, Ji-Young; Kim, Kwang-Heon; Kim, Hyun-Kyung; Park, Sang-Hoon; Roh, Kwang Chul; Kim, Kwang-Bum

    2015-08-05

    One-dimensional, hydrous ruthenium oxide nanotubes (RuO2·1.84H2O) have been successfully achieved using a template-free, microwave-hydrothermal process. These were found to be amorphous in nature and have a large specific surface area of 250 m(2)·g(-1), producing a specific and volumetric capacitance of 511 F·g(-1) and 531 F·cm(-3), respectively, at a discharging current density of 0.5 A·g(-1). When used as an electrode material in an electrochemical capacitor or ultracapacitor, they produced a significant improvement in capacitance, rate capability, and cyclability that can be attributed to the hollow nature of tubes allowing greater contact between the active surface of the electrode and the electrolyte.

  13. Carbon nanotube materials from hydrogen storage

    SciTech Connect

    Dillon, A.C.; Bekkedahl, T.A.; Cahill, A.F.

    1995-09-01

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

  14. Electrochemical Characterization of Carbon Nanotubes for Fuel Cell MEA's

    NASA Technical Reports Server (NTRS)

    Panagaris, Jael; Loyselle, Patricia

    2004-01-01

    Single-walled and multi-walled carbon nanotubes from different sources have been evaluated before and after sonication to identify structural differences and evaluate electrochemical performance. Raman spectral analysis and cyclic voltammetry in situ with QCM were the principle means of evaluating the tubes. The raman data indicates that sonication in toluene modifies the structural properties of the nanotubes. Sonication also affects the electrochemical performance of single-walled nanotubes and the multi-walled tubes differently. The characterization of different types of carbon nanotubes leads up to identifying a potential candidate for incorporating carbon nanotubes for fuel cell MEA structures.

  15. Carbon Nanotubes for Space Photovoltaic Applications

    NASA Technical Reports Server (NTRS)

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

    2007-01-01

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

  16. Multifunctional Carbon Nanotube Fiber Composites

    DTIC Science & Technology

    2007-11-02

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

  17. Mesoscale mechanics of twisting carbon nanotube yarns

    NASA Astrophysics Data System (ADS)

    Mirzaeifar, Reza; Qin, Zhao; Buehler, Markus J.

    2015-03-01

    Fabricating continuous macroscopic carbon nanotube (CNT) yarns with mechanical properties close to individual CNTs remains a major challenge. Spinning CNT fibers and ribbons for enhancing the weak interactions between the nanotubes is a simple and efficient method for fabricating high-strength and tough continuous yarns. Here we investigate the mesoscale mechanics of twisting CNT yarns using full atomistic and coarse grained molecular dynamics simulations, considering concurrent mechanisms at multiple length-scales. To investigate the mechanical response of such a complex structure without losing insights into the molecular mechanism, we applied a multiscale strategy. The full atomistic results are used for training a coarse grained model for studying larger systems consisting of several CNTs. The mesoscopic model parameters are updated as a function of the twist angle, based on the full atomistic results, in order to incorporate the atomistic scale deformation mechanisms in larger scale simulations. By bridging across two length scales, our model is capable of accurately predicting the mechanical behavior of twisted yarns while the atomistic level deformations in individual nanotubes are integrated into the model by updating the parameters. Our results focused on studying a bundle of close packed nanotubes provide novel mechanistic insights into the spinning of CNTs. Our simulations reveal how twisting a bundle of CNTs improves the shear interaction between the nanotubes up to a certain level due to increasing the interaction surface. Furthermore, twisting the bundle weakens the intertube interactions due to excessive deformation in the cross sections of individual CNTs in the bundle.

  18. Spectroscopic study of carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Curran, Seamus; Weldon, Declan N.; Blau, Werner J.; Zandbergen, Henny W.; Kastner, J.; Kuzmany, Hans

    1994-11-01

    We present a comprehensive experimental study of the vibrational spectra of nanotubes. There are two main lines observed in the Raman spectrum, one positioned at 1350 cm-1, the D line, and the other at 1580 cm-1, the G line. Both these lines are very similar to those seen with disordered graphite. The disorder induced D line is very weak compared to the G line which is indicative of high crystalline materials. The position and intensity of the D line strongly depends on the energy of the exciting laser. This dispersion effect was also observed for graphitic particles and may be explained by a photoselective resonance process of nanotubes with different sizes. There are two optically active modes in the Infrared spectrum for highly orientated polycrystalline graphite which are the E1u and A2u modes. The E1u mode is positioned at 1587 cm-1 while the A2u mode is positioned at 868 cm-1. The Infrared spectrum of the nanotubes shows both modes although the E1u mode is downshifted to 1575 cm-1.

  19. Giant Surface Conductivity Enhancement in a Carbon Nanotube Composite by Ultraviolet Light Exposure.

    PubMed

    Long, Christian J; Orloff, Nathan D; Twedt, Kevin A; Lam, Thomas; Vargas-Lara, Fernando; Zhao, Minhua; Natarajan, Bharath; Scott, Keana C; Marksz, Eric; Nguyen, Tinh; Douglas, Jack F; McClelland, Jabez; Garboczi, Edward; Obrzut, Jan; Liddle, J Alexander

    2016-09-07

    Carbon nanotube composites are lightweight, multifunctional materials with readily adjustable mechanical and electrical properties-relevant to the aerospace, automotive, and sporting goods industries as high-performance structural materials. Here, we combine well-established and newly developed characterization techniques to demonstrate that ultraviolet (UV) light exposure provides a controllable means to enhance the electrical conductivity of the surface of a commercial carbon nanotube-epoxy composite by over 5 orders of magnitude. Our observations, combined with theory and simulations, reveal that the increase in conductivity is due to the formation of a concentrated layer of nanotubes on the composite surface. Our model implies that contacts between nanotube-rich microdomains dominate the conductivity of this layer at low UV dose, while tube-tube transport dominates at high UV dose. Further, we use this model to predictably pattern conductive traces with a UV laser, providing a facile approach for direct integration of lightweight conductors on nanocomposite surfaces.

  20. Device study, chemical doping, and logic circuits based on transferred aligned single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Wang, Chuan; Ryu, Koungmin; Badmaev, Alexander; Patil, Nishant; Lin, Albert; Mitra, Subhasish; Wong, H.-S. Philip; Zhou, Chongwu

    2008-07-01

    In this paper, high-performance back-gated carbon nanotube field-effect transistors based on transferred aligned carbon nanotubes were fabricated and studies found that the on/off ratio can reach 107 and the current density can reach 1.6μA/μm after electrical breakdown. In addition, chemical doping with hydrazine was used to convert the p-type aligned nanotube devices into n-type. These devices were further utilized to demonstrate various logic circuits, including p-type metal-oxide-semiconductor inverters, diode-loaded inverters, complementary metal-oxide-semiconductor inverters, NAND, and NOR gates. This approach could work as the platform for future nanotube-based nanoelectronics.

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

    NASA Technical Reports Server (NTRS)

    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.

  2. Carbon nanotube formation by laser direct writing

    SciTech Connect

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

    2008-07-14

    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. Water transport with a carbon nanotube pump.

    PubMed

    Duan, Wen Hui; Wang, Quan

    2010-04-27

    Transportation of water molecules in a carbon nanotube based on an energy pump concept is investigated by molecular dynamics simulations. A small portion of the initially twisted wall of a carbon nanotube is employed to function as an energy pump for possible smooth transportation of water molecules. The momentum and resultant force on a water molecule and the corresponding displacement and velocity of the molecule are particularly studied to disclose the transportation process. The efficiency of the transportation is found to be dependent on the size of the energy pump. Once the process for the transportation of one molecule is elucidated, transportations of 20 water molecules are simulated to investigate the effect of the environmental temperature and fluctuations in the nanotube channel on the transportation. It is revealed that the accelerated period of multiple water molecules is longer than that in the transportation of a single water molecule. In addition, the fluctuations in the nanotube wall due to the buckling propagation and a higher environmental temperature will all lead to obvious decreases in the water velocity and hence retard the transportation process.

  4. Developing Carbon Nanotube Standards at NASA

    NASA Technical Reports Server (NTRS)

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

    2007-01-01

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

  5. Metal-enhanced fluorescence of carbon nanotubes.

    PubMed

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

    2010-11-17

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

  6. Remote Joule heating by a carbon nanotube.

    PubMed

    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.

  7. Developing Carbon Nanotube Standards at NASA

    NASA Technical Reports Server (NTRS)

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

    2007-01-01

    Single wall carbon nanotubes (SWCNTs) are currently being produced and processed by several methods. Many researchers are continuously modifying existing methods and developing new methods to incorporate carbon nanotubes into other materials and utilize the phenomenal properties of SWCNTs. These applications require availability of SWCNTs with known properties and there is a need to characterize these materials in a consistent manner. In order to monitor such progress, it is critical to establish a means by which to define the quality of SWCNT material and develop characterization standards to evaluate of nanotube quality across the board. Such characterization standards should be applicable to as-produced materials as well as processed SWCNT materials. In order to address this issue, NASA Johnson Space Center has developed a protocol for purity and dispersion characterization of SWCNTs (Ref.1). The NASA JSC group is currently working with NIST, ANSI and ISO to establish purity and dispersion standards for SWCNT material. A practice guide for nanotube characterization is being developed in cooperation with NIST (Ref.2). Furthermore, work is in progress to incorporate additional characterization methods for electrical, mechanical, thermal, optical and other properties of SWCNTs.

  8. High-Performance Supercapacitor Electrode Based on Cobalt Oxide-Manganese Dioxide-Nickel Oxide Ternary 1D Hybrid Nanotubes.

    PubMed

    Singh, Ashutosh K; Sarkar, Debasish; Karmakar, Keshab; Mandal, Kalyan; Khan, Gobinda Gopal

    2016-08-17

    We report a facile method to design Co3O4-MnO2-NiO ternary hybrid 1D nanotube arrays for their application as active material for high-performance supercapacitor electrodes. This as-prepared novel supercapacitor electrode can store charge as high as ∼2020 C/g (equivalent specific capacitance ∼2525 F/g) for a potential window of 0.8 V and has long cycle stability (nearly 80% specific capacitance retains after successive 5700 charge/discharge cycles), significantly high Coulombic efficiency, and fast response time (∼0.17s). The remarkable electrochemical performance of this unique electrode material is the outcome of its enormous reaction platform provided by its special nanostructure morphology and conglomeration of the electrochemical properties of three highly redox active materials in a single unit.

  9. Graphene nanoribbons production from flat carbon nanotubes

    SciTech Connect

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

    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.

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

    PubMed

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

    2015-05-21

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

  11. Automated manipulation of carbon nanotubes using atomic force microscopy.

    PubMed

    Zhang, Chao; Wu, Sen; Fu, Xing

    2013-01-01

    The manipulation of carbon nanotubes is an important and essential step for carbon-based nanodevice or nanocircuit assembly. However, the conventional push-and-image approach of manipulating carbon nanotubes using atomic force microscopy has low efficiency on account of the reduplicated scanning process during manipulation. In this article, an automated manipulation system is designed and tested. This automated manipulation system, which includes an atomic force microscope platform and a self-developed computer program for one-dimensional manipulation, is capable of automatically moving any assigned individual carbon nanotube to a defined target location without any intermediate scanning procedure. To demonstrate the high-efficiency of this automated manipulation system and its potential applications in nanoassembly, two experiments were conducted. The first experiment used this system to manipulate a carbon nanotube to a defined target location. In the second experiment, this system was used to automatically manipulate several carbon nanotubes for generating and translating a defined pattern of nanotubes.

  12. Automated circuit fabrication and direct characterization of carbon nanotube vibrations

    PubMed Central

    Zeevi, G.; Shlafman, M.; Tabachnik, T.; Rogachevsky, Z.; Rechnitz, S.; Goldshtein, I.; Shlafman, S.; Gordon, N.; Alchanati, G.; Itzhak, M.; Moshe, Y.; Hajaj, E. M.; Nir, H.; Milyutin, Y.; Izraeli, T. Y.; Razin, A.; Shtempluck, O.; Kotchtakov, V.; Yaish, Y. E.

    2016-01-01

    Since their discovery, carbon nanotubes have fascinated many researchers due to their unprecedented properties. However, a major drawback in utilizing carbon nanotubes for practical applications is the difficulty in positioning or growing them at specific locations. Here we present a simple, rapid, non-invasive and scalable technique that enables optical imaging of carbon nanotubes. The carbon nanotube scaffold serves as a seed for nucleation and growth of small size, optically visible nanocrystals. After imaging the molecules can be removed completely, leaving the surface intact, and thus the carbon nanotube electrical and mechanical properties are preserved. The successful and robust optical imaging allowed us to develop a dedicated image processing algorithm through which we are able to demonstrate a fully automated circuit design resulting in field effect transistors and inverters. Moreover, we demonstrate that this imaging method allows not only to locate carbon nanotubes but also, as in the case of suspended ones, to study their dynamic mechanical motion. PMID:27396506

  13. Lipid/Polyelectrolyte coatings to control carbon nanotubes intracellular distribution.

    PubMed

    Romero, G; Estrela-Lopis, I; Rojas, E; Llarena, I; Donath, E; Moya, S E

    2012-06-01

    Carbon Nanotubes have been functionalized with a layer of poly (sulfopropyl methacrylate) synthesized from silane initiators attached to the walls of the Carbon nanotubes. On top of the poly sulfo propyl methacrylate, lipid vesicles composed of 75% 1,2-Dioleoyl-sn-Glycero-3-Phosphocholine and 25% 1,2-Dioleoyl-sn-Glycero-3-[Phospho-L-Serine] were assembled. The surface modification of the Carbon Nanotubes and lipid assembly were followed by TEM. Confocal Raman Microscopy was used to study the uptake and localization of the surface modified Carbon Nanotubes in the HepG2 cell line. The localization of the Carbon Nanotubes in the cells was affected by the surface coating. It was found that poly (sulfopropyl methacrylate) and lipid modified Carbon Nanotubes were present in the region of the lipid bodies in the cytoplasm.

  14. Method of making carbon nanotubes on a substrate

    DOEpatents

    Gao, Yufei; Liu, Jun

    2006-03-14

    The present invention includes carbon nanotubes whose hollow cores are 100% filled with conductive filler. The carbon nanotubes are in uniform arrays on a conductive substrate and are well-aligned and can be densely packed. The uniformity of the carbon nanotube arrays is indicated by the uniform length and diameter of the carbon nanotubes, both which vary from nanotube to nanotube on a given array by no more than about 5%. The alignment of the carbon nanotubes is indicated by the perpendicular growth of the nanotubes from the substrates which is achieved in part by the simultaneous growth of the conductive filler within the hollow core of the nanotube and the densely packed growth of the nanotubes. The present invention provides a densely packed carbon nanotube growth where each nanotube is in contact with at least one nearest-neighbor nanotube. The substrate is a conductive substrate coated with a growth catalyst, and the conductive filler can be single crystals of carbide formed by a solid state reaction between the substrate material and the growth catalyst. The present invention further provides a method for making the filled carbon nanotubes on the conductive substrates. The method includes the steps of depositing a growth catalyst onto the conductive substrate as a prepared substrate, creating a vacuum within a vessel which contains the prepared substrate, flowing H2/inert (e.g. Ar) gas within the vessel to increase and maintain the pressure within the vessel, increasing the temperature of the prepared substrate, and changing the H2/Ar gas to ethylene gas such that the ethylene gas flows within the vessel. Additionally, varying the density and separation of the catalyst particles on the conductive substrate can be used to control the diameter of the nanotubes.

  15. Magnetic configuration dependence of magnetoresistance in a Fe-porphyrin-like carbon nanotube spintronic device

    SciTech Connect

    Zeng, Jing; Chen, Ke-Qiu

    2014-01-20

    By using nonequilibrium Green's functions in combination with the density functional theory, we investigate the spin-dependent transport properties in a Fe-porphyrin-like carbon nanotube spintronic device. The results show that magnetoresistance ratio is strongly dependent on the magnetic configuration of the Fe-porphyrin-like carbon nanotube. Under the application of the external magnetic field, the magnetoresistance ratio of the device can be increased from about 19% to about 1020% by tuning the magnetic configuration in the device. Our results confirm that the magnetic configuration is a key factor for obtaining a high-performance spintronic device.

  16. Process for derivatizing carbon nanotubes with diazonium species

    NASA Technical Reports Server (NTRS)

    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##.

  17. High-performance supercapacitors based on freestanding carbon-based composite paper electrodes

    NASA Astrophysics Data System (ADS)

    Yun, Young Soo; Lee, Min Eui; Joo, Min Jae; Jin, Hyoung-Joon

    2014-01-01

    Using a simple filtration method, we fabricate freestanding carbon-based composite paper electrodes (F-CCPEs), based on acid-treated carbon nanotubes (a-CNTs) and microporous carbon-based nanoplates containing numerous heteroatoms (H-CMNs). The F-CCPEs exhibited a high electrical conductivity of 2.3 × 102 S cm-1 and a high surface area of 1211.7 m2 g-1; moreover, they had numerous electroative heteroatoms and showed mechanical flexibility. Therefore, F-CCPEs without current collectors and binder show a superior electrochemical performance. In particular, the prepared F-CCPEs exhibit high capacitances of 275 and 148 F g-1 in aqueous and organic electrolytes, respectively. In addition, the specific energy density and specific power density of these F-CCPEs were found to be 63 Wh kg-1 and 140 kW kg-1, respectively, with good cyclic stability, even after 20,000 charge/discharge cycles.

  18. Growth of semiconducting single-wall carbon nanotubes with a narrow band-gap distribution

    PubMed Central

    Zhang, Feng; Hou, Peng-Xiang; Liu, Chang; Wang, Bing-Wei; Jiang, Hua; Chen, Mao-Lin; Sun, Dong-Ming; Li, Jin-Cheng; Cong, Hong-Tao; Kauppinen, Esko I.; Cheng, Hui-Ming

    2016-01-01

    The growth of high-quality semiconducting single-wall carbon nanotubes with a narrow band-gap distribution is crucial for the fabrication of high-performance electronic devices. However, the single-wall carbon nanotubes grown from traditional metal catalysts usually have diversified structures and properties. Here we design and prepare an acorn-like, partially carbon-coated cobalt nanoparticle catalyst with a uniform size and structure by the thermal reduction of a [Co(CN)6]3− precursor adsorbed on a self-assembled block copolymer nanodomain. The inner cobalt nanoparticle functions as active catalytic phase for carbon nanotube growth, whereas the outer carbon layer prevents the aggregation of cobalt nanoparticles and ensures a perpendicular growth mode. The grown single-wall carbon nanotubes have a very narrow diameter distribution centred at 1.7 nm and a high semiconducting content of >95%. These semiconducting single-wall carbon nanotubes have a very small band-gap difference of ∼0.08 eV and show excellent thin-film transistor performance. PMID:27025784

  19. Chemically Functionalized Carbon Nanotubes as Substrates for Neuronal Growth

    PubMed Central

    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

  20. Deformation Response of Conformally Coated Carbon Nanotube Forests

    DTIC Science & Technology

    2013-11-05

    SUPPLEMENTARY NOTES 14. ABSTRACT The deformation mechanism and mechanical properties of carbon nanotube (CNT) forests conformally coated with alumina...of conformally coated carbon nanotube forests Parisa Pour Shahid Saeed Abadi1, Matthew R Maschmann2,3, Jeffery W Baur2, Samuel Graham1,4 and Baratunde...stacks.iop.org/Nano/24/475707 Abstract The deformation mechanism and mechanical properties of carbon nanotube (CNT) forests conformally coated with alumina using

  1. Varied morphology carbon nanotubes and method for their manufacture

    DOEpatents

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

    2007-01-02

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

  2. Electron Damage Effects on Carbon Nanotube Thin Films

    DTIC Science & Technology

    2013-03-01

    ELECTRON DAMAGE EFFECTS ON CARBON NANOTUBE THIN FILMS THESIS Jeremy S. Best, Captain, USMC AFIT-ENP-13-M-37 DEPARTMENT OF THE AIR FORCE AIR...Government and is not subject to copyright protection in the United States. AFIT-ENP-13-M-37 ELECTRON DAMAGE EFFECTS ON CARBON NANOTUBE THIN FILMS...M-37 ELECTRON DAMAGE EFFECTS ON CARBON NANOTUBE THIN FILMS Jeremy S. Best, BS Aerospace Engineering Captain, USMC Approved: Dr. John McClory

  3. Engineering of High-Toughness Carbon Nanotubes Hierarchically Laminated Composites

    DTIC Science & Technology

    2012-01-27

    REPORT TYPE Final 3. DATES COVERED (From - To) Jul-10 - Jul-11 4. TITLE AND SUBTITLE Program Title: ENGINEERING OF HIGH-TOUGHNESS CARBON NANOTUBES ...LIMITATION OF ABSTRACT 18. NUMBER OF PAGES 19a. NAME OF RESPONSIBLE PERSON Program Title: ENGINEERING OF HIGH-TOUGHNESS CARBON NANOTUBES ...Ashby plots can be attained (Fig. 2B). 5. New doping method of carbon nanotubes was developed. Funding Profile: (Give the fiscal year funding

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

    DTIC Science & Technology

    2013-05-01

    Application of Conductive Carbon Nanotube Fibers and Composites: Gas Sensor by Padraig G. Moloney and Enrique V. Barrera ARL-CR-0714 May...2013 Application of Conductive Carbon Nanotube Fibers and Composites: Gas Sensor Padraig G. Moloney and Enrique V. Barrera Dept. of...From - To) June 2011 to April 2012 4. TITLE AND SUBTITLE Application of Conductive Carbon Nanotube Fibers and Composites: Gas Sensor 5a

  5. Thermogravimetric Analysis of Single-Wall Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    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.

  6. Lightweight, Durable Army Antennas Using Carbon Nanotube Technology

    DTIC Science & Technology

    2013-01-01

    Chapter 1. Keller, S. D.; Zaghloul, A. I.; Shanov, V.; Schulz, M. J.; Mast, D. B. Carbon Nanotube Yarn and Sheet for Electromagnetics- Antennas...Lightweight, Durable Army Antennas Using Carbon Nanotube Technology (Final Report) by Steven D. Keller and Amir I. Zaghloul ARL-TR-6323...1197 ARL-TR-6323 January 2013 Lightweight, Durable Army Antennas Using Carbon Nanotube Technology (Final Report) Steven D. Keller and

  7. A Carbon Nanotube Cable for a Space Elevator

    ERIC Educational Resources Information Center

    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…

  8. Selective synthesis and device applications of semiconducting single-walled carbon nanotubes using isopropyl alcohol as feedstock.

    PubMed

    Che, Yuchi; Wang, Chuan; Liu, Jia; Liu, Bilu; Lin, Xue; Parker, Jason; Beasley, Cara; Wong, H-S Philip; Zhou, Chongwu

    2012-08-28

    The development of guided chemical vapor deposition (CVD) growth of single-walled carbon nanotubes provides a great platform for wafer-scale integration of aligned nanotubes into circuits and functional electronic systems. However, the coexistence of metallic and semiconducting nanotubes is still a major obstacle for the development of carbon-nanotube-based nanoelectronics. To address this problem, we have developed a method to obtain predominantly semiconducting nanotubes from direct CVD growth. By using isopropyl alcohol (IPA) as the carbon feedstock, a semiconducting nanotube purity of above 90% is achieved, which is unambiguously confirmed by both electrical and micro-Raman measurements. Mass spectrometric study was performed to elucidate the underlying chemical mechanism. Furthermore, high performance thin-film transistors with an on/off ratio above 10(4) and mobility up to 116 cm(2)/(V·s) have been achieved using the IPA-synthesized nanotube networks grown on silicon substrate. The method reported in this contribution is easy to operate and the results are highly reproducible. Therefore, such semiconducting predominated single-walled carbon nanotubes could serve as an important building block for future practical and scalable carbon nanotube electronics.

  9. Carbon Nanotube Flexible and Stretchable Electronics

    NASA Astrophysics Data System (ADS)

    Cai, Le; Wang, Chuan

    2015-08-01

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

  10. Density controlled carbon nanotube array electrodes

    DOEpatents

    Ren, Zhifeng F.; Tu, Yi

    2008-12-16

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

  11. Carbon Nanotube Flexible and Stretchable Electronics.

    PubMed

    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.

  12. Electrical properties of carbon nanotube FETs

    NASA Astrophysics Data System (ADS)

    Mizutani, T.; Ohno, Y.; Kishimoto, S.

    2008-08-01

    The electrical properties of carbon nanotube FETs (CNTFETs) have been studied in detail. The conduction type of the CNTFETs was dependent on the work function of the contact metal, which suggests that Fermi level pinning at the metal/nanotube interface is not strong. Based on the two-probe and four-probe resistance measurements, it has been shown that the carrier transport at the contact is explained by the edge contact model even in the diffusive regime. The chemical doping using F4TCNQ was effective in reducing not only the channel resistance but also the contact resistance. In the CNTFETs fabricated using plasma-enhanced (PE) CVD-grown nanotubes, the drain current of the most of the devices could be modulated by the gate voltage with small OFF current suggesting the preferential growth of the nanotubes with semiconducting behavior. Multichannel top-gate CNTFETs with horizontally-aligned nanotubes as channels have been successfully fabricated using CNT growth on the ST-cut quartz substrate, arc-discharge plasma deposition of the catalyst metal, and ALD gate insulator deposition. The devices show normally-on and n-type conduction property with a relatively-high ON current of 13 mA/mm. CNTFETs with nanotube network have also been fabricated by direct growth on the SiO2/Si substrate using grid-inserted PECVD and using catalyst formed on the channel area of the FETs. The uniformity of the electrical properties of the network channel CNTFETs were very good. Finally, it has been shown that the surface potential profile measurement based on the electrostatic force detection in the scanning probe microscopy was effective in studying the behavior of the CNTFETs such as the transient behavior and the effect of the defects.

  13. Excited State Dynamics in Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Miyamoto, Yoshiyuki

    2004-03-01

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

  14. High-Performance Field-Emission Properties of Boron Nitride Nanotube Field Emitters.

    PubMed

    Yun, Ki Nam; Sun, Yuning; Han, Jun Soo; Song, Yoon-Ho; Lee, Cheol Jin

    2017-01-18

    Boron nitride nanotubes (BNNTs) have attracted considerable attention as a field emission material because of their high mechanical strength, high negative electron affinity, and high oxidation resistance. Nevertheless, the obtained field-emission properties of BNNTs have indicated poor emission performance, which is a very high turn-on electric field with a low emission current. We fabricated BNNT field emitters and investigated their field-emission properties. The field-emission properties of the BNNT field emitters were considerably enhanced compared to those of other BN nanomaterial-based field emitters. The turn-on and the threshold electric fields of the BNNT field emitter were 3.1 and 5.4 V/μm at the gap distance of 750 μm, respectively. Both the turn-on and the threshold electric fields of the BNNT field emitters were decreased by increasing the gap distance between the emitter tip and the anode electrode. Degradation of the emission current during field emission operation for 20 h showed no significant difference according to the gap distance. Emission current fluctuation of the BNNT field emitters showed that the smaller gap was more unstable than the larger gap. The enhanced emission properties are mainly attributed to the small diameter, high-quality, and straight structure of BNNTs as well as the stable network formation of the BNNT film with good mechanical and electrical contact between the BNNTs and the cathode electrode. The remarkable emission performance of the BNNT field emitters might have promising applications for various field-emission devices.

  15. Carbon Nanotubes by CVD and Applications

    NASA Technical Reports Server (NTRS)

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

    2001-01-01

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

  16. Postgrowth Microwave Treatment to Align Carbon Nanotubes

    DTIC Science & Technology

    2013-03-01

    pp. 8671–8675. [47] Chen, C. M., Chen, M., Peng, Y. W., Yu, H. W., and Chen, C. F., 2006, “High Efficiency Microwave Digestion Purification of Multi...Y. W., Lin, C. H., Chang, L. W., and Chen, C. F., 2005, “ Microwave Digestion and Acidic Treatment Procedures for the Purification of Multi-Walled...Postgrowth Microwave Treatment to Align Carbon Nanotubes J. J. Nguyen T. L. Bougher P. Pour Shahid Saeed Abadi A. Sharma George W. Woodruff School of

  17. Carbon Nanotube Membranes for Water Purification

    NASA Astrophysics Data System (ADS)

    Bakajin, Olgica

    2009-03-01

    Carbon nanotubes are an excellent platform for the fundamental studies of transport through channels commensurate with molecular size. Water transport through carbon nanotubes is also believed to be similar to transport in biological channels such as aquaporins. I will discuss the transport of gas, water and ions through microfabricated membranes with sub-2 nanometer aligned carbon nanotubes as ideal atomically-smooth pores. The measured gas flow through carbon nanotubes exceeded predictions of the Knudsen diffusion model by more than an order of magnitude. The measured water flow exceeded values calculated from continuum hydrodynamics models by more than three orders of magnitude and is comparable to flow rates extrapolated from molecular dynamics simulations and measured for aquaporins. More recent reverse osmosis experiments reveal ion rejection by our membranes. Based on our experimental findings, the current understanding of the fundamentals of water and gas transport and of ion rejection will be discussed. The potential application space that exploits these unique nanofluidic phenomena will be explored. The extremely high permeabilities of these membranes, combined with their small pore size will enable energy efficient filtration and eventually decrease the cost of water purification.[4pt] In collaboration with Francesco Fornasiero, Biosciences and Biotechnology Division, PLS, LLNL, Livermore, CA 94550; Sangil Kim, NSF Center for Biophotonics Science & Technology, University of California at Davis, Sacramento CA 95817; Jung Bin In, Mechanical Engineering Department, UC Berkeley, Berkeley CA 94720; Hyung Gyu Park, Jason K Holt, and Michael Stadermann, Biosciences and Biotechnology Division, PLS, LLNL; Costas P. Grigoropoulos, Mechanical Engineering Department, UC Berkeley; Aleksandr Noy, Biosciences and Biotechnology Division, PLS, LLNL and School of Natural Sciences, University of California at Merced.

  18. Octagonal Defects at Carbon Nanotube Junctions

    PubMed Central

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

    2013-01-01

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

  19. Torsional electromechanical systems based on carbon nanotubes.

    PubMed

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

    2012-11-01

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

  20. Super-tough carbon-nanotube fibres

    NASA Astrophysics Data System (ADS)

    Dalton, Alan B.; Collins, Steve; Muñoz, Edgar; Razal, Joselito M.; Ebron, Von Howard; Ferraris, John P.; Coleman, Jonathan N.; Kim, Bog G.; Baughman, Ray H.

    2003-06-01

    The energy needed to rupture a fibre (its toughness) is five times higher for spider silk than for the same mass of steel wire, which has inspired efforts to produce spider silk commercially. Here we spin 100-metre-long carbon-nanotube composite fibres that are tougher than any natural or synthetic organic fibre described so far, and use these to make fibre supercapacitors that are suitable for weaving into textiles.