POLYMER FUNCTIONALIZED SINGLE-WALLED CARBON NANOTUBE COMPOSITES AND SEMI-FLUORINATED QUATERNARY AMMONIUM POLYMER COLLOIDS AND COATINGS By ABHIJIT PAUL Bachelor of Science in Chemistry Assam University Silchar, Assam 2001 Master of Science in Polymer Science Tezpur University Tezpur, Assam 2003 Submitted to the Faculty of the Graduate College of the Oklahoma State University in partial fulfillment of the requirements for the Degree of DOCTOR OF PHILOSOPHY July, 2012ii POLYMER FUNCTIONALIZED SINGLE-WALLED CARBON NANOTUBE COMPOSITES AND SEMI-FLUORINATED QUATERNARY AMMONIUM POLYMER COLLOIDS AND COATINGS Dissertation Approved: Dr. Warren T. Ford Dissertation Adviser Dr. Kenneth D. Berlin Dr. Jeffery L. White Dr. Kevin D. Ausman Dr. James P. Wicksted Dr. Sheryl A. Tucker Dean of the Graduate Collegeiii PREFACE In my Ph.D. research I have studied single-walled carbon nanotube (SWCNT) polymer composites that potentially have unique combination of excellent mechanical strength, electrical conductivity, ...

Page contains details about osmium clusters inside single walled carbon nanotubes . It has composition images, properties, Characterization methods, synthesis, applications and reference articles : nano.nature.com

Page contains details about hematoporphyrin monomethyl ether hyaluronic acid-derivatized single walled carbon nanotubes . It has composition images, properties, Characterization methods, synthesis, applications and reference articles : nano.nature.com

Polymer nanocomposites reinforced with carbon nanotubes have attracted recently. The properties of nanocomposites depend greatly on the chemistry of polymer matrices, nature of nanofillers and the way in which they are prepared. Properties of epoxy resin have a significant influence on the mechanical properties of the nanocomposites. Effect of matrix hardness on the mechanical properties of the carbon nanotubes reinforced epoxy composite has been reported. In this study, epon-828 and jeffamine-D400 were used. Multiwall carbon nanotubes/epoxy resin composites have been fabricated. The mechanical properties of the composite with different weight percentages of nanotubes have been investigated. A sonication technique was used to disperse nanotubes in epoxy matrix. Viscosity of the polymer nanocomposite has been investigated, too. These results are very important in fabrication of composite material such as VRTM method and etc. Particular attention is paid on the structure property relationship of such

TY - JOUR. T1 - Inhibitory effects of multiwall carbon nanotubes with high iron impurity on viability and neuronal differentiation in cultured PC12 cells. AU - Meng, Li. AU - Jiang, Aihua. AU - Chen, Rui. AU - Li, Chen zhong. AU - Wang, Liming. AU - Qu, Ying. AU - Wang, Peng. AU - Zhao, Yuliang. AU - Chen, Chunying. PY - 2013/11/8. Y1 - 2013/11/8. N2 - The increasing use of carbon nanotubes (CNTs) in biomedical applications has garnered a great concern on their potential negative effects to human health. CNTs have been reported to potentially disrupt normal neuronal function and they were speculated to accumulate and cause brain damage, although a lot of distinct and exceptional properties and potential wide applications have been associated with this material in neurobiology. Fe impurities strapped inside the CNTs may be partially responsible for neurotoxicity generation. In the present study, we selected rat pheochromocytoma (PC12) cells to investigate and compare the effects of two kinds of ...

Hybrid electronics. Using a new method for precisely controlling the deposition of carbon, researchers have demonstrated a technique for connecting multi-walled carbon nanotubes to the metallic pads of integrated circuits without the high interface resistance produced by traditional fabrication techniques.. Based on electron beam-induced deposition (EBID), the work is believed to be the first to connect multiple shells of a multi-walled carbon nanotube to metal terminals on a semiconducting substrate, which is relevant to integrated circuit fabrication. Using this three-dimensional fabrication technique, researchers at the Georgia Institute of Technology developed graphitic nanojoints on both ends of the multi-walled carbon nanotubes, which yielded a 10-fold decrease in resistivity in its connection to metal junctions.. The technique could facilitate the integration of carbon nanotubes as interconnects in next-generation integrated circuits that use both silicon and carbon components. The ...

The size dependent colloidal behavior of aqueous dispersions of carboxylated multiwall carbon nanotubes (c-MWCNTs) is presented. The presence of carboxylic groups provided electrostatic stabilization in water, where the size affected agglomeration. While aspect ratio did not show any definite correlation, th

In this paper, we directly measured the temperature dependence of Thermal Boundary Resistances (TBRs) between multiwall carbon nanotubes (MWCNTs) and different materials at elevated temperatures. Using the steady-state heat flow and the non-contacted

Molecular dynamic calculations of pullout in multiwall carbon nanotubes (CNTs) demonstrate that inner walls with fractured ends have pullout forces similar to3-4 times larger than those for capped ends, due to deformation of the fractured end, quantitatively accounting for experiments. Under pressure, Amontons law applies to an area of contact at the fractured end, with mu=0.13-0.33. Defects in the CNT walls affect the force, suggesting a mechanism for the observed stick-slip behavior and an increase of pullout force with decreasing embedded length. The results have implications for CNT composite strength and toughness. Xia, Z.; Curtin, W. A.

Multiwall carbon nanotubes represent a low-dimensional material that could serve as building blocks for future carbon-based nanoelectronics. The understand

High Pt loading on functionalized multiwall carbon nanotubes as a highly efficient cathode electrocatalyst for proton exchange membrane fuel cells

The small internal length scales of nanomaterials/nano-devices may call the direct application of classical continuum models into question. In this research, a nonlocal elastic shell model, which takes the small scale effects into account, is developed to study the thermal buckling behavior of multi-walled carbon nanotubes. The multi-walled carbon nanotubes are considered as concentric thin shells coupled with the van der Waals forces between adjacent nanotubes. Closed form solutions are formulated for two types of thermal buckling of a double-walled carbon nanotube: Radial thermal buckling (as in a shell under external pressure) and axial thermal buckling. The effects of small scale effects are demonstrated, and a significant influence of internal characteristic parameters such as the length of the ...

Article Removal of tetracycline antibiotic from contaminated water media by multi-walled carbon nanotubes: operational variables, kinetics, and equilibrium studies. Multi-walled carbon nanotubes (MWCNTs) were purified and oxidized by a 4 mol L−1 mixt...

TY - JOUR. T1 - Mouse pulmonary dose- and time course-responses induced by exposure to nitrogen-doped multi-walled carbon nanotubes. AU - Porter, Dale W.. AU - Orandle, Marlene. AU - Zheng, Peng. AU - Wu, Nianqiang. AU - Hamilton, Raymond F.. AU - Holian, Andrij. AU - Chen, Bean T.. AU - Andrew, Michael. AU - Wolfarth, Michael G.. AU - Battelli, Lori. AU - Tsuruoka, Shuji. AU - Terrones, Mauricio. AU - Castranova, Vince. N1 - Funding Information: The authors would like to thank Phillip Brown (NIOSH) for the editorial review of the manuscript. Publisher Copyright: ©, This work was authored as part of the Contributors official duties as an Employee of the United States Government and is therefore a work of the United States Government. In accordance with 17 U.S.C. 105, no copyright protection is available for such works under U.S. Law.. PY - 2020/1/2. Y1 - 2020/1/2. N2 - Objective: In this study, we compared in vitro and in vivo bioactivity of nitrogen-doped multi-walled carbon nanotubes ...

Single-walled carbon nanotubes (SWCNT), nano-cylinders with an extremely small diameter (1-2 nm) and high aspect ratio, have unique physico-chemical, electronic and mechanical properties and may exhibit unusual interactions with cells and tissues, thus necessitating studies of their toxicity and health effects. Manufactured SWCNT usually contain significant amounts of iron that may act as a cataly

The interaction between some heavy metal ions such as of Pb(II), Cd(II) and Cu(II) ions from aqueous solution adsorbed by single walled carbon nanotube (SWCNTs) and carboxylate group functionalized single walled carbon nanotube (SWCNT-COOH) surfaces were studied by atomic absorption spectroscopy. The effect of contact time, pH, initial concentration of ion, ionic strength and temperature on the adsorption of ion were investigated. The results indicated that Langmuir model fits adsorption isotherm data better than the Freundlich model. The results also demonstrated that SWCNT-COOH surfaces can more effectively adsorb mentioned ions than a SWCNTs surface. Maximum adsorption capacities (qm) for Pb(II), Cu(II) and Cd(II) ions onto SWCNT-COOH were obtained as 96.02, 77.00 and 55.89 mg/g, respectively and by SWCNTs, as 33.55, 24.29 and 24.07 mg/g, respectively. Thermodynamic parameters values showed that the adsorption of ions on SWCNT-COOH and SWCNTs at 283-313 K is spontaneous and endothermic.

This invention relates generally to a forming an array of single-wall carbon nanotubes (SWNT) in an electric field and compositions thereof. In one embodiment, a purified bucky paper of single-wall carbon nanotubes is used as the starting material. Upon oxidative treatment of the bucky paper surface, many tube and/or rope ends protrude up from the surface of the paper. Disposing the resulting bucky paper in an electric field results in the protruding tubes and or ropes of single-wall carbon nanotubes aligning in a direction substantially perpendicular to the paper surface. These tubes tend to coalesce to form a molecular array. In another embodiment, a molecular array of SWNTs can be made by combing the purified bucky paper starting material with a sharp microscopic tip to align the nanotubes ...

This invention is directed to making chemical derivatives of carbon nanotubes and to uses for the derivatized nanotubes, including making arrays as a basis for synthesis of carbon fibers. In one embodiment, this invention also provides a method for preparing single wall carbon nanotubes having substituents attached to the side wall of the nanotube by reacting single wall carbon nanotubes with fluorine gas and recovering fluorine derivatized carbon nanotubes, then reacting fluorine derivatized carbon nanotubes with a nucleophile. Some of the fluorine substituents are replaced by nucleophilic substitution. If desired, the remaining fluorine can be completely or partially eliminated to produce single wall carbon nanotubes having substituents attached to the side wall of the nanotube. The substituents will, of course, be dependent on the nucleophile, and preferred nucleophiles include alkyl lithium species such as methyl lithium. Alternatively, fluorine may be fully or partially removed from fluorine

This invention is directed to making chemical derivatives of carbon nanotubes and to uses for the derivatized nanotubes, including making arrays as a basis for synthesis of carbon fibers. In one embodiment, this invention also provides a method for preparing single wall carbon nanotubes having substituents attached to the side wall of the nanotube by reacting single wall carbon nanotubes with fluorine gas and recovering fluorine derivatized carbon nanotubes, then reacting fluorine derivatized carbon nanotubes with a nucleophile. Some of the fluorine substituents are replaced by nucleophilic substitution. If desired, the remaining fluorine can be completely or partially eliminated to produce single wall carbon nanotubes having substituents attached to the side wall of the nanotube. The substituents will, of course, be dependent on the nucleophile, and preferred nucleophiles include alkyl lithium species such as methyl lithium. Alternatively, fluorine may be fully or partially removed from fluorine

Multi-walled carbon nanotubes are of great interest - primarily based upon their electrical and mechanical properties. The main application is in polymer composites - where at low concentrations they provide substantial improvements in electrical and mechanical performance. They also are very effective pigments and UV stabilizers. Discussed are the performance and applications of thermoplastic, thermoset, and elastomer composites comprising Arkema Graphistrength® multi-walled carbon nanotube products, with emphasis on the effect of proper dispersion, and the excellent utility of masterbatches.

The work presented in this thesis is concerned with organic photovoltaic devices (OPVs), in particular with the use of multi-wall carbon nanotubes (MWCNT) to improve device performance. The initial chapters introduce the subject areas of OPVs, carbon nanotubes (CNT) and experimental techniques. Within the thesis, it is demonstrated that MWCNT can be utilised as an interpenetrating, work function tuneable, electrode in bi-layer OPVs. A remarkably low concentration of MWCNT (~1 wt.%) uniformly distributed within the donor layer is shown to greatly increase the cell fill factor (FF) without complicating the process of device fabrication. Furthermore, functionalising the MWCNT with polar surface groups is shown to be an effective means of modifying the open circuit voltage (Voc). This study clearly demonstrates the potential of this approach to significantly increase the power conversion efficiency of bi-layer OPVs. We also introduce, a water soluble acid oxidised multi-wall carbon nanotube ...

Template-guided growth of carbon nanotubes using anodized aluminum oxide nanopore templates provides vertically aligned, untangled planarized arrays of multiwall carbon nanotubes with Ohmic back contacts. Growth by catalytic chemical vapor deposition results in multiwall carbon nanotubes with uniform diameters and crystalline quality, but varying lengths. The nanotube lengths can be trimmed to uniform heights above the template surface using ultrasonic cutting, for example. The carbon nanotube site density can be controlled by controlling the catalyst site density. Control of the carbon nanotube site density enables various applications. For example, the highest possible site density is preferred for thermal interface materials, whereas, for field emission, significantly lower site densities are preferable.

LONDON - The global carbon nanotubes market is dominated by the Asia-Pacific region, followed by the USA and Europe. The growth of the Chinese, Korean and Indian markets and the technological breakthroughs in the field of carbon nanotubes are the main factors contributing to the growth of the Asia-Pacific market for carbon nanotubes. The Europe market for carbon nanotubes is the fastest growing market due to the financial support of the local authorities.. The global market for carbon nanotubes is ruled by several players such as Arkema, Showa Denko K.K, Bayer MaterialScience AG, Hanwha Nanotech Corporation, Shenzhen Nanotech Port Co. Ltd., amidst others. By 2016, the carbon nanotubes industry is likely to outnumber USD 1 billion. The prices for carbon nanotubes are predicted to decrease by around 15% in the nearest future.. New report The Global Market For Carbon Nanotubes To 2020 created by Future Markets analyzes the global carbon nanotubes market. The study offers comprehensive data on the ...

A technique to deterministically manipulate individual Carbon Nanotubes (CNT) has been the brick-wall for the boom of CNT based devices. Here we demonstrate dielectrophoresis as an efficient technique to trap individual Single Walled Carbon Nanotubes (SWCNT) and Multi Walled Carbon Nanotubes (MWCNT). A coarse control on the number of nanotubes deposited was achieved by controlling the applied voltage and duration of deposition; additionally, a circuit that cuts off the electric field necessary for further CNT deposition after one single CNT deposition has been used. By using an external series resistance during dielectrophoresis, higher than the contact resistance of the carbon nanotube obtained after dielectrophoresis, we are able to limit the deposition to individual nanotubes. The contact resistance of a single SWCNT obtained by the coarse technique was found to be 80 MΩ. Hence we chose a limiting series resistance of 1 GΩ. P-type silicon substrate with resistivity of 0.1-0.5 Ωcm with ...

TY - JOUR. T1 - Instillation versus inhalation of multiwalled carbon nanotubes. T2 - Exposure-related health effects, clearance, and the role of particle characteristics. AU - Silva, Rona M.. AU - Doudrick, Kyle. AU - Franzi, Lisa M.. AU - Teesy, Christel. AU - Anderson, Donald S.. AU - Wu, Zheqiong. AU - Mitra, Somenath. AU - Vu, Vincent. AU - Dutrow, Gavin. AU - Evans, James E.. AU - Westerhoff, Paul. AU - Van Winkle, Laura S.. AU - Raabe, Otto G.. AU - Pinkerton, Kent E. PY - 2014/9/23. Y1 - 2014/9/23. N2 - Inhaled multiwalled carbon nanotubes (MWCNTs) may cause adverse pulmonary responses due to their nanoscale, fibrous morphology and/or biopersistance. This study tested multiple factors (dose, time, physicochemical characteristics, and administration method) shown to affect MWCNT toxicity with the hypothesis that these factors will influence significantly different responses upon MWCNT exposure. The study is unique in that (1) multiple administration methods were tested using particles from ...

Owing to their unusual properties, carbon nanostructures such as nanotubes and fullerenes have caused many new nanomechanical devices to be proposed. One such application is that of nanoscale oscillators which operate in the gigahertz range, the so-called gigahertz oscillators. Such devices have potential applications as ultrafast optical filters and nano-antennae. While there are difficulties in producing micromechanical oscillators which operate in the gigahertz range, molecular dynamical simulations indicate that nanoscale devices constructed of multi-walled carbon nanotubes or single-walled carbon nanotubes and C60 fullerenes could feasibly operate at these high frequencies. This paper investigates the suction force experienced by either an atom or a C60 fullerene molecule located in the vicinity of an open end of a single-walled carbon nanotube. The atom is modelled as a point mass, the fullerene as an averaged atomic mass distributed over the surface of a sphere. In both cases, the carbon ...

Carbon nanotubes (CNTs) have been one of the most studied nanoparticles and incorporated into various consumer products. It has been reported that CNTs can enter groundwater systems by accidental or intentional release into the subsurface. As transport mechanisms of CNTs are not well understood, investigation on mobility of CNTs in the subsurface will be helpful to define disposal regulations of CNTs. The objective in this study is to investigate the effect of solution chemistry (pH and ionic strength) and physical factors (collector grain size and flow rate) on the transport of multi-walled carbon nanotubes (MWCNTs). One-dimensional convection-dispersion model incorporated with collector efficiency for cylindrical nanoparticles was used to simulate the transport of MWCNTs in porous media. It was observed that higher pH led to increase in mobility of MWCNTs. The critical point of ionic strength for MWCNTs getting mobilized was narrowed down in the range of 2 to 5 mM. It was observed that the ...

TY - JOUR. T1 - Mechanism of induction of binucleated cells by multiwalled carbon nanotubes as revealed by live-cell imaging analysis. AU - Yasui, Manabu. AU - Kamoshita, Nagisa. AU - Nishimura, Tetsuji. AU - Honma, Masamitsu. N1 - Publisher Copyright: © 2015 Yasui et al.. PY - 2015. Y1 - 2015. N2 - Introduction: Asbestos-induced formation of mesothelioma has been attributed to phenotypic and morphological changes in cells caused by polyploidization and aneuploidization, and multiwalled carbon nanotubes (MWCNTs) are suspected to have similar adverse effects due to the similarity in their physical form. MWCNTs and crocidolite, a kind of asbestos, show similar genotoxicity characteristics in vitro, including induction of binucleated cells. We here focused on the mechanisms underlying polyploidization during cell division on exposure to MWCNTs and conducted confocal live-cell imaging analysis using MDA-435 human breast cancer cells in which chromosomes and centromeres were visualized using ...

He ion irradiation effects on multiwalled carbon nanotubes structure / E. M. Elsehly, N. G. Chechenin, A. V. Makunin et al. // European Physical Journal D. - 2017. - Vol. 71, no. 4. - P. 71-79. Samples of multi-walled carbon nanotubes (MWNTs) were irradiated with 80 keV He ions. Scanning electron microscopy (SEM) inspection showed that the average outer diameters of the tube decreased as a result of ion irradiation. The samples were also characterized using Raman spectrometry by analysis of the intensity of main bands in the spectra of virgin and irradiated MWNT samples. Modifications of the disorder mode (D-band) and the tangential mode (G-band) were studied as a function of irradiation fluences. Raman spectra showed that as the fluence increases, the MWNTs first show disorder due to the produced defects, and then amorphization under still higher fluence of ion irradiation. Thermal and athermal mechanisms of the radiation induced MWNTs modifications are discussed. [ DOI ...

COOH Functionalized Multi-Walled Carbon Nanotubes, Multi-Walled Carbon, MWCNTs, MWCNTs powders Suppliers, Manufacturers, Exporters, HONGWU INTERNATIONAL GROUP LTD - Code 1167

Recently alcohols and ketones have been employed to sensitize CNT by CVD. A study has shown the importance of the chemical nature of those carbon precursors on the characteristics of the CNT (carbon nanotubes) obtained. In the present work we show the influence of the catalyst employed on the synthesis of functionalized multiwall carbon nanotubes (MWCNTs) utilizing acetone as carbon source and cobalt nitrate Co(NO|sub|3|/sub|)|sub|2|/sub| as catalyst.

Experimental procedures have been developed to prepare carbon nanotubes (CNTs) decorated by metal oxides nanoparticles for gas sensing applications. For decoration of carbon nanotubes with Sn and Cu oxides, the concentration of precursors and time of sonication were found to be crucial parameters, to control the size and density of nanoparticles on the nanotubes surface. In the case of CNTs decorated with Ti oxides, the pH value of the solution was found to play a key role in the final size of the nanoparticles. The material decorated with SnO2 was tested with H2S and changes in the conductivity showed the potential of this material for gas sensing application. © The Electrochemical Society ...

A group of researchers from several institutions in Japan has observed superconductivity a phenomenon in which electrons flow with no resistance in billionth-of-a-meter sized cylindrical carbon molecules known as multi-walled carbon nanotubes. The nanotubes ability to superconduct adds to their many intriguing electrical and physical characteristics. Moreover, it increases the likelihood that carbon nanotubes will one day drastically improve electronics, building materials, and many other products ...

Shape memory polymers (SMPs) are expected to play more and more important roles in space-deployable structures, smart actuators, and other high-tech areas. Nevertheless, because of the difficulties in fabrication and the programmability of temporary shape recovery, SMPs have not yet been widely applied in real fields. It is ideal to incorporate the different independent functional building blocks into a material. Herein, we designed a simple method to incorporate four functional building blocks: a neat epoxy-based shape memory (neat SMEP) resin, an SMEP composited with Fe3O4 (SMEP-Fe3O4), an SMEP composited with multiwalled carbon nanotubes, and an SMEP composited with p-aminodiphenylimide into a multicomposite, in which the four region surfaces could be programmed with different language code patterns according to a preset command by imprint lithography ...

According to some embodiments, a method for separating a first fraction of a single wall carbon nanotubes and a second fraction of single wall carbon nanotubes includes, but is not limited to: flowing a solution comprising the nanotubes into a dielectrophoresis chamber; applying a DC voltage, in combination with an AC voltage, to the dielectrophoresis chamber; and collecting a first eluent from the dielectrophoresis chamber, wherein the first eluent comprises the first fraction and is depleted of the second fraction, wherein the first and second fractions differ by at least one of conductivity, diameter, length, and combinations thereof.

Multi-walled carbon nanotubes (MWCNTs) are new manufactured nanomaterials with a wide spectrum of commercial applications. To address the hypothesis that MWCNTs cause persistent pulmonary pathology, C57BL/6J mice were exposed by pharyngeal aspiration to 10, 20, 40 or 80 μg of MWCNTs (mean dimensions of 3.9 μm × 49 nm) or vehicle. Lungs were preserved at 1, 7, 28 and 56 days post- exposure to determine the potential regions and target cells for impact by MWCNT lung burden. Morphometric measurement of Sirius Red staining was used to assess the connective tissue response. At 56 days post-exposure, 68.7 ± 3.9, 7.5 ± 1.9 and 22.0 ± 5.1 percent (mean ± SE, N = 8) of the MWCNT lung burden were in alveolar macrophages, alveolar tissue and granulomatous lesions, respectively. The subpleural tissues contained 1.6% of the MWCNT lung burden. No MWCNTs were found in the airways at 7, 28 or 56 days after aspiration The connective tissue in the alveolar interstitium demonstrated a progressive increase in

This technology uses polymer adsorbed to single walled carbon nanotubes as molecular recognition molecules. Single walled carbon nanotubes (SWNTs) are composed of single layers of graphene rolled into nanometer-scale cylinders. SWNTs have well defined optical properties, including non-photobleachable near IR fluorescence. When polymer is adsorbed onto the surface of the SWNTs, a complex 3D structure is formed that allows specific binding of different molecules. Changing the identity of the polymer allows different molecular binding specificity and slight modifications to the polymer tunes the binding affinity to the molecule. When molecules bind to the polymer-SWNT complex the photoluminescent properties of the complex change, which allows detection of bound molecule. The polymer-SWNT complex therefore provides a new way of detecting molecular analytes by binding specifically to the analyte molecule and simultaneously producing an optical readout of analyte presence. The inventors performed ...

Multiwall carbon nanotubes are produced by decomposition of acetylene at 600 degreesC on metal catalysts supported on NaY zeolite. The support and the metal are eliminated by dissolving them in aqueous hydrofluoric acid (HF). Two methods were used to eliminate the pyrolitic carbon: oxidation in air at 500 degreesC and oxidation by potassium permanganate in acidic solution at 70 degreesC. The progress and efficacy of the purification methods are verified by TEM. The properties of the purified multiwalled carbon nanotubes are probed using C-13 and Xe-129 NMR spectroscopy under continuous-flow optical-pumping conditions. Xenon is shown to penetrate the interior of the nanotubes. A distribution of inner tube diameters gives rise to chemical shift dispersion. When the temperature is lowered, an increasing fraction of xenon resides inside the nanotubes and is not capable of exchanging with xenon in the interparticle space. In the case of the permanganate-oxidized sample, rapid xenon relaxation is ...

TY - JOUR. T1 - Electrocatalyzed O 2 response of myoglobin immobilized on multi-walled carbon nanotube forest electrodes. AU - Pacios, M.. AU - Del Valle, M.. AU - Bartroli, J.. AU - Esplandiu, M. J.. PY - 2009/10. Y1 - 2009/10. N2 - Direct electrochemistry and activity of myoglobin (Mb) immobilized on carbon nanotube (CNT) forest electrodes were investigated by probing mainly its electrocatalytical response towards oxygen. The protein was anchored on the CNT electrodes through carbodiimide coupling, which was shown to provide long term stability. The electrochemical response was monitored as a function of oxygen concentration and pH. Conformational changes together with the consequent loss of oxygen affinity were recorded at low pH, which delimits the operative range of the Mb/CNT electrodes for sensing purposes. In general, it can be concluded that CNT forests constitute suitable platforms for Mb attachment without compromising the protein bioactivity and by keeping at the same time the direct ...

1. Introduction. Carbon nanotubes (CNTs) have been proposed as the ideal metal catalyst support for electrocatalytic and sensing applications because of their unique electrical properties, high chemical stability and high surface-to-volume ratios.1 Decoration of the walls of carbon nanotubes (CNTs)2 with functional groups3 and/or nanoparticles has been performed to add additional functionality to CNTs. In recent years, decoration of CNTs has been used to improve performance of their various applications4 such as making nanotubes magnetic,5 to grow secondary structures inside the nanotubes to increase the available surface for catalysis6 or in electronics.7 Modern electronics devices based on carbon nanotubes (CNTs) have shown that their performance is influenced by a potential barrier existing at the metal-CNT contact that governs the electron injection into the carbon nanotubes.7. To functionalize the CNTs with metal nanoparticles, an ionic adsorption followed by a direct heating can be ...

TY - JOUR. T1 - Electron spin resonance study of single-walled carbon nanotubes. AU - Abiad Monge, Aida. AU - Ferrer-Anglada, N. AU - Lloveras, V. AU - Vidal-Gancedo, J. AU - Roth, S.. N1 - NO DATA USED. PY - 2011. Y1 - 2011. N2 - Studies of electron spin resonance (esr) are reported on several types of single-walled carbon nanotubes (swcnts) synthesized by different methods. We work both with the obtained samples, which contained randomly distributed semiconducting and metallic swcnts, and with selected 99% semiconducting or metallic swcnts. Our aim is to use esr spectroscopy in order to assess the quality of carbon nanotubes. We analyze the temperature dependence of esr spectra in the range 4-300?k and report the temperature dependence of the linewidth, the intensity and the asymmetry factor (i+/i-) of the esr lines. The esr response from the arc discharge swcnts produced using non-magnetic pt/rh catalyst and from the selected semiconducting tubes exhibits an asymmetric line with an intensity ...

TY - JOUR. T1 - Effects of Multiwalled Carbon Nanotube Surface Modification and Purification on Bovine Serum Albumin Binding and Biological Responses. AU - Bai, Wei. AU - Wu, Zheqiong. AU - Mitra, Somenath. AU - Brown, Jared M.. N1 - Funding Information: This work was supported by grants from the National Institutes of Health (R01 ES019311, R01 ES023209, and R03 ES023036). Publisher Copyright: © 2016 Wei Bai et al.. PY - 2016. Y1 - 2016. N2 - Carboxylation of multiwalled carbon nanotubes (MWCNTs) has been used to improve solubility in aqueous systems and for further functionalization with biologically active moieties for biomedical uses. An important consideration is that oxidation debris is generated during the process of carboxylation, which can be removed by base washing. We hypothesized that surface modification as well as purification by debris removal may alter physicochemical properties of MWCNTs and their ability to bind proteins. We utilized pristine MWCNT, carboxylated MWCNTs ...

We have measured the current induced voltage drop along an individual multiwall carbon nanotube as a function of the distance to the current injecting electrode. The measurements have been performed at room temperature using scanning probe potentiometry combined with scanning electron microscopy. For a nanotube with an incomplete outer shell, a sharp potential jump was observed at the end of the outermost shell. The electric potential variation along the carbon nanotube has been used to determine the contact resistance between metal electrodes and the tube, the intrashell resistance, and the intershell conductance. ...

Dr. Karl Gross, of Hy-Energy LLC, kindly suggested that high-quality carbon nanotube arrays are needed for research and development of high-sensitivity gas sensors. We are pleased to offer highly aligned arrays of multiwall carbon nanotubes (MWCNTs) as new products in our catalog. These arrays, available on silicone (Aldrich Product No. 687804) or copper (Aldrich Product No. 687812) substrates, can provide a unique platform for a wide range of materials research and development, including gas adsorption sensor and sensor substrates,1 catalysts, electron emission sources,2 and battery and capacitor development.3. ...

Un-modified and modified multi-walled carbon nanotubes (MWCNTs) produced and optimized by King Fahd University of Petroleum and Minerals (KFUPM) in Dhahran, Saudi Arabia were utilized in this study to remove trivalent Arsenic As (III) and divalent Mercury Hg (II) from water. The effect of solution conditions such as initial solution pH, initial metal ions concentration, dosage of the adsorbent i.e. CNT, contact time and mixing rate were investigated. Generally the percentage uptake increased with an increase in pH from pH 4 to 8. The optimum pH found in this study was 8 which showed 100 % removal of 0.1 ppm Hg (II) ions using 200 ppm of un-modified MWCNTs and 87.8 % of 10 ppm As (III) ions using 400 ppm of Iron-Impregnated MWCNTs from aqueous solution. The adsorption capacity gradually increased with the increase in agitation rate from 50 to 150 rpm, in which higher removal of Hg (II) and As (III) was observed at 150 rpm. The removal of Hg (II) and As (III) was optimal for higher dosage of CNTs, ...

Poly(3,4-ethylenedioxxythiophene) (PEDOT), polyaniline (PANI) and polythiophene (PTh) based multi-walled carbon nanotube (MWCNT) composites were successfully prepared using RF-rotating plasma grafting method. Morphological characterizations of composites were determined using scanning electron microscopy (SEM), which showed that conducting polymers (CPs) of PEDOT, PANI and PTh were coated on the surface of CNTs. The surface properties of the Carbon Nanotube (CNT) composites were also determined by using Infrared Spectra (FT-IR), X-ray Photon Spectra (XPS), and Scanning Electron Microscopy-Energy Dispersive X-ray Spectra (SEM-EDX) analysis. X-ray photon spectra results confirmed the formation of the composites. Composites of MWCNT were used in dye-sensitized solar cells (DSSCs) as counter electrodes and exhibited short-circuit photocurrent densities of 11.19, 10.70 and 8.54mA/cm(2) for PANI/MWCNT, PTh/MWCNT and PEDOT/CNT, respectively. ...

Normal Raman scattering (NRS) and surface-enhanced Raman scattering (SERS) have been performed on single-walled and multi-walled carbon nanotubes to observe fine vibrational structures at the low- and intermediate-frequency regions. Following surface enhancement with silver particles, it is observed that the radial breathing mode, tangential mode, the overtone phonon peaks and coupling phonon peaks are suppressed. In contrast, the Z-breathing phonons, which correspond to vibration along the nanotube axis, and which are usually weak or non-existent in NRS, become enhanced in the SERS of both SWNTs and MWNTs. © 2003 Elsevier Science B.V. All rights reserved ...

Green biosynthesis of silver - functionalized multiwalled carbon nanotube (Ag/FMWCNT) nanohybride from silver nitrate solution using water extract of Satureja hortensis L as reducing agent and FMWCNT as anchoring agent at room condition was succesfully carried out. Water-soluble organics present in the plant materials were mainly responsible for the reduction of silver ions to nano-sized Ag particles The synthesized nanocomposite were characterized using ultraviolet-visible spectroscopy (UV-Vis), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and powder X-ray diffraction (XRD). The UV-Vis spectra of the Ag/FMWCNT nanocomposite showed absorption peak at around 401 nm. SEM and TEM studies showed that the average particles size of Ag/FMWCNT nanocomposite were about 16.05 nm and also XRD patterns indicated that the structure of the nanocomposite is face-centered cubic. The antibacterial effects of Ag/FMWCNT on Gram positive and Gram negative bacteria were also performed.

In the present work, three junctions were fabricated on textile fabric as an alternative substrate for harvesting piezoelectric potential. First junction was formed on ordinary textile as (textile/multi-walled carbon nanotube film/zinc oxide nanowires (S1: T/CNTs/ZnO NWs)) and the other two were formed on conductive textile with the following layer sequence: conductive textile/zinc oxide nanowires (S2: CT/ZnO NWs) and conductive textile/multi-walled carbon nanotubes film/zinc oxide nanowires (S3: CT/CNTs/ZnO NWs). Piezoelectric potential was harvested by using atomic force microscopy in contact mode for the comparative analysis of the generated piezoelectric potential. ZnO NWs were synthesized by using the aqueous chemical growth method. Surface analysis of the grown nanostructures was performed by using scanning electron microscopy and transmission electron microscopy. The growth orientation and crystalline size were studied by using X-ray diffraction technique. This study reveals that textile ...

In this study, the structure-property relationships in thermoplastic polyurethane (TPU) filled with multi-walled carbon nanotubes (MWCNTs) were investigated. Firstly, the contribution of MWCNTs to the melt shear viscosity and the pressure-volume-temperature (pVT) behavior was investigated. Secondly, injection-molded samples and 2 mm diameter filaments of TPU/MWCNT composites were fabricated and their mechanical and electrical properties analyzed. It was found that the melt processability of TPU/MWCNT composites is not affected by the addition of a small amount (1-5 wt.%) of MWCNTs, all composites displaying shear-thinning at high shear rates. The mechanical and electrical properties of the TPU/MWCNT composites were substantially enhanced with the addition of MWCNTs. However, the conductivity values of composites processed by injection molding were two and three orders of magnitude lower than those of composites processed by extrusion, highlighting the role of melt shear viscosity on the ...

High frequency S parameters characterization up to 10 GHz for back-gate carbon nanotube field-effect transistors (CNFETs) was carried for the first time. T

TY - JOUR. T1 - Mechanics of hydrogen storage in carbon nanotubes. AU - Chen, Y. L.. AU - Liu, B.. AU - Wu, J.. AU - Huang, Y.. AU - Jiang, Hanqing. AU - Hwang, K. C.. PY - 2008/11. Y1 - 2008/11. N2 - A continuum mechanics model is established for hydrogen storage in single- and multi-wall carbon nanotubes (CNTs) and the bundle of single-wall CNTs. The model accounts for the deformation of CNTs, and van der Waals interactions among hydrogen molecules and between hydrogen and carbon atoms. The analytical expressions of hydrogen storage (number of hydrogen molecules per unit volume) in CNTs are obtained, and are validated by atomistic simulations. CNTs are categorized as tiny, small, medium and large CNTs; tiny CNTs cannot achieve the goals of hydrogen storage (62 kg/m3 and 6.5 wt% of hydrogen set by the US Department of Energy) without fracture; small CNTs are strained during hydrogen storage; medium CNTs can achieve the above goals without the strain and do not self collapse; and large CNTs may ...

The present work considers an adsorptive removal of Indigo carmine (IC) dye onto nanotube carbon (CNTs). The pure CNTs were prepared via chemical vapor deposition (CVD) method utilizing methane gas...

Carbon nanotubes and graphene have many interesting properties. To exploit the properties in applications their synthesis and incorporation in devices has to be understood and controlled. This thesis is based on experimental studies on synthesis of carbon nanotubes and fabrication of nanoelectromechanical systems from carbon nanotubes and graphene. Vertically aligned nanotube arrays with heights over 800 µm have been grown using acetylene with iron as catalyst on alumina support using thermal chemical vapor deposition. By varying the partial pressure of acetylene it was found that the addition-rate of carbon was proportional to the coverage of acetylene molecules on the catalyst nanoparticle. In certain conditions the macroscopic pattern of the catalyst areas influenced the microscopic properties of the carbon nanotubes. It was shown that the initial carbon-precursor flow conditions could determine the number of walls produced. The amount of carbon incorporated into nanotubes was constant but ...

Understanding how electrons and phonons relax in energy and momentum is one of the current goals in carbon nanotube spectroscopy as well as an important step toward developing novel electronic and optoelectronic devices based on carbon nanotubes. Here, we investigate the polarization anisotropy of coherent phonon (CP) dynamics of radial breathing mode (REM) phonons in highly-aligned single-walled carbon nanotubes (SWNTs). Using CP spectroscopy, we measure REM CPs as a function of angle for two different geometries and in both cases, we observe quenching of the RBM when polarization is perpendicular to the nanotubes. We also make progress in understanding the role of dark excitons in SWNTs at ultralow temperatures. Measuring the magnetic field dependence to 5 T, we obtained an unexpected zero-field photoluminescence (PL) and PL brightening at 50 mK. To explain this contradiction with current theory, we introduced a non-thermal distribution of excitons into current theory ...

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Electrical circuits are made with several basic parts, such as transistors and diodes. Researchers at other organisations have demonstrated preliminary transistors and diodes built from carbon nanotubes, but GEs device performs about as well as a conventional silicon diode, unlike earlier efforts, Lee said.. Chip designers have been able to increase performance and decrease transistor size for years using CMOS (complementary metal-oxide semiconductor) silicon technology, but are starting to run into problems stemming from current leakage. The dimensions of modern semiconductors are growing so small that electrons can leak through the structures on a chip and escape as heat.. Carbon nanotubes are under intense scrutiny as a possible successor to silicon technology over the next decade or so. A carbon nanotube is simply a cylinder made from carbon atoms that is about 10,000 times thinner than a human hair.. The nanotubes are strong and exhibit many thermal and electrical properties desirable to ...

We developed a tip-enhanced Raman spectrometer (TERS) with reflection mode. The instrument, with a scanning shear-force microscope (ShFM) and a side-illumination Raman spectroscope, can overcome the diffraction limit and has high sensitivity. A chemical method to fabricate optical fiber probes with Ag coating is proposed. The local electromagnetic responses of the silver-coated optical fiber probe are numerically analyzed by the finite-difference time-domain method, and the excitation wavelength is optimized to resonate with the localized surface plasmons (LSP) of the probe tip. The instrument is applied to investigate a single multiwall carbon nanotube. The experiment results indicate that our TERS instrument has a spatial resolution better than ...

iii 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 zonefolding model (with ?0 ...

Abstract: The thermal conductivity of individual multiwalled carbon nanotubes was measured by utilizing the four-point-probe third-harmonic method, based on the fact that the third harmonic amplitude and phase as a response to applied alternate current at fundamental frequency, ω, can be expressed in terms of thermal conductivity and diffusivity. To this end, a microfabricated device composed of four metal electrodes was modified to manufacture nanometer-sized wires by using a focused ion beam source. A carbon nanotube could then be suspended over a deep trench milled by the focused ion beam, preventing heat loss to the substrate. Compared with the two-point-probe technique, a significant improvement in accuracy is assured by using four probes, because the contact contribution to the determination of the thermal conductivity is eliminated, making it possible to measure the correct signals of first and third harmonics. The multiwalled carbon nanotube was modeled as a one-dimensional diffusive ...

The main objective of the thesis is to propose the methods of determining vibration behavior of carbon nanotubes (CNTs) using continuum models and finite element models. Secondary objective is to find the effect of van der Waals force on vibration of multiwalled carbon nanotubes . The study of vibration behavior of CNTs is important because of their potential engineering applications such as nano-mechanical resonators and tips of scanning probe instruments where they are subjected to mechanical vibrations. Continuum modeling is based on an elastic beam model. The interlayer van der Waals interactions are represented by Lennard-Jones potential. In finite element modeling, single walled nanotubes (SWNTs) are modeled as finite beam elements and multi-walled nanotubes (MWNTs) as finite solid elements. The interlayer van der Waals interactions are simulated by distributed springs. The proposed finite element approach and continuum approach for vibration analysis of CNTs are verified by comparing the results

A novel electrochemical sensor for sensitive detection of doxepin was prepared, which was based on a glassy carbon electrode modified with poly(4-aminobenzoic acid)/multi-walled carbon nanotubes composite film [poly(4-ABA)/MWNTs/GCE]. The sensor was characterized by scanning electron microscopy and electrochemical methods. It was observed that poly(4-ABA)/MWNTs/GCE showed excellent preconcentration function and electrocatalytic activities towards doxepin. Under the selected conditions, the anodic peak current was linear to the logarithm of doxepin concentration in the range from 1.0 ´ 10−9 to 1.0 ´ 10−6 M, and the detection limit obtained was 1.0 × 10−10 M. The poly(4-ABA)/MWNTs/GCE was successfully applied in the measurement of doxepin in commercial pharmaceutical formulations, and the analytical accuracy was confirmed by comparison with a conventional ultraviolet spectrophotometry assay.

Carbon nanotubes (CNTs) have been regarded as a promising material for highly sensitive gas sensors due to their excellent material properties combined with their one-dimensional structural advantages, i.e., a high surface-to-volume ratio. Here we demonstrate a CNT-based gas sensor based on assembling highly purified, solution-processed 99.9% semiconducting CNT networks bridged by palladium source/drain electrodes in a field-effect transistor (FET) configuration with a local back-gate electrode. We investigated the gas responses of the CNT-FETs under different controlled operating regimes for the enhanced detection of H-2 and NO2 gases using sensors with various physical dimensions. With the aid of the CNTs with high semiconducting purity (99.9%), we achieved excellent electrical properties and gas responses in the sensors and clearly determined that the operating regimes and physical dimensions of the sensors should be appropriately adjusted for enhanced sensing performance, depending on the ...

Dumee, Ludovic F., Sears, Kallista, Schutz, Jurg A., Finn, Niall, Duke, Mikel, Mudie, Stephen, Kirby, Nigel and Gray, Stephen 2013, Small angle X-ray scattering study of carbon nanotube forests densified into long range patterns by controlled solvent evaporation, Journal of colloid and interface science, vol. 407, pp. 556-560, doi: 10.1016/j.jcis.2013.06.018. ...

Aligned carbon naotubes are very desirable for carbon based electronic devices and integrated circuits owing to their advantages of registration-free fabrication, high device yield, and small device-to-device variation. For the aligned nanotubes, one of the most important technology components is to increase the nanotube density. High density aligned nanotubes can be extremely helpful to improve the current driving capability, transconductance, and cut-off frequency of the devices. Here in this talk, we report low-pressure chemical vapor deposition (LPCVD) ethanol synthesis of high density aligned nanotubes with density as high as 30 tubes/µm. Then a facile stacking multiple transfer technique was used to further increase the nanotube density to | 55 tubes/µm. Furthermore, high-performance back-gated carbon nanotube field-effect transistors were fabricated on these ultra high density aligned nanotubes and the devices exhibit on-current density of 92.4 µA/µm, normalized transconductance of 13.3 µS

That is, theyre looking for an electronics material that both conducts electricity better and allows for smaller transistors. One key material being researched for that purpose is carbon, in the form of carbon nanotubes. Carbon nanotubes are molecules of carbon that are structured as cylinders on the nanoscale. For the past few years, researchers have been using carbon nanotubes to make transistors instead of silicon. Now a team at USC has created a carbon nanotube transistor that has an extrinsic frequency (which defines its practical performance limit) of 25 GHz - 40% faster than the current record holder, which operates at 15 GHz. That makes the teams nanotube transistor the fastest in the world. ...

In order for carbon nanotube (CNT) electrical devices to be fabricated, it is necessary to obtain modifiable operation characteristics. Developing parametric equations to achieve this controllability in the vertical field-effect transistor (FET) design is an important first step toward fabrication. The capacitances associated with the physical geometry of the porous anodic alumina (PAA)-based CNTFET are explored and developed into a parametric equation for the unity current gain frequency (fT) ...

In order for carbon nanotube (CNT) electrical devices to be fabricated, it is necessary to obtain modifiable operation characteristics. Developing parametric equations to achieve this controllability in the vertical field-effect transistor (FET) design is an important first step toward fabrication. The capacitances associated with the physical geometry of the porous anodic alumina (PAA)-based CNTFET are explored and developed into a parametric equation for the unity current gain frequency (fT) ...

Graphene nanoribbons (GNRs, also called nano-graphene ribbons or nano-graphite ribbons) are strips of graphene with width less than 50 nm. Graphene ribbons were introduced as a theoretical model by Mitsutaka Fujita and coauthors to examine the edge and nanoscale size effect in graphene. Large quantities of width-controlled GNRs can be produced via graphite nanotomy, where applying a sharp diamond knife on graphite produces graphite nanoblocks, which can then be exfoliated to produce GNRs. GNRs can also be produced by unzipping or axially cutting nanotubes. In one such method multi-walled carbon nanotubes were unzipped in solution by action of potassium permanganate and sulfuric acid. In another method GNRs were produced by plasma etching of nanotubes partly embedded in a polymer film. More recently, graphene nanoribbons were grown onto silicon carbide (SiC) substrates using ion implantation followed by vacuum or laser annealing. The latter technique allows any pattern to be written on SiC ...

Molecular motions of proteins and their flexibility induce conformational states required for enzyme catalysis, signal transduction, and protein-protein interactions. However, the mechanisms for protein transitions between conformational states are often poorly understood, especially in the millisecond to microsecond range where conventional optical techniques and computational modeling are most limited. To investigate the microsecond dynamics of enzymes, single-walled carbon nanotube - field-effect transistors (SWCNT-FETs) were used as single-molecule biosensors. The SWCNT-FETs have sufficient sensitivity and bandwidth to monitor the conformational motions and processivity of an individual cAMP-dependent protein kinase A (PKA) molecule. Protein attachment is accomplished by functionalizing a SWCNT-FET device with a single protein and measuring the conductance versus time through the device as it is submerged in an electrolyte solution. PKA-functionalized nanocircuits elucidated the time PKA ...

Theres a lot more in the article, but the bottom line is that the current sate of the science indicates that, if exposure to carbon nanotubes can occur, care needs to be taken.. As a side note, back in 2007 I questioned wisdom of assuming carbon nanotubes were just as safe as any other form of carbon. At the time, suppliers like Cheap Tubes classified them in Material Safety Data Sheets (MSDS) as Synthetic Graphite, with safe exposure levels of between 2 mg/m3 - 5 mg/3 (essentially treating carbon nanotubes as a nuisance dust).. In 2013, the National Institute for Occupational Safety and Health recommended an occupational exposure limit of 1 µg/m3 - a thousand times lower than what manufacturers and distributers were using at the time.. To see whats changed, I checked Cheap Tubes current MSDS. The exposure limit for carbon nanotubes is still listed as between 2 mg/m3 and 5 mg/3 for respirable particles, and up to 15 mg/m3 for inhalable particles. So still just a nuisance dust.. Clearly, ...

The application of hyaluronic acid-derivatized carbon nanotubes in hematoporphyrin monomethyl ether-based photodynamic therapy for in vivo and in vitro cancer treatment Jinjin Shi,* Rourou Ma,* Lei Wang, Jing Zhang, Ruiyuan Liu, Lulu Li, Yan Liu, Lin Hou, Xiaoyuan Yu, Jun Gao, Zhenzhong Zhang School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, Henan, People's Republic of China*These authors contributed equally to this workAbstract: Carbon nanotubes (CNTs) have shown great potential in both photothermal therapy and drug delivery. In this study, a CNT derivative, hyaluronic acid-derivatized CNTs (HA-CNTs) with high aqueous solubility, neutral pH, and tumor-targeting activity, were synthesized and characterized, and then a new photodynamic therapy agent, hematoporphyrin monomethyl ether (HMME), was adsorbed onto the functionalized CNTs to develop HMME-HA-CNTs. Tumor growth inhibition was investigated both in vivo and in vitro by a combination of photothermal therapy and

TY - JOUR. T1 - Removal of sulfamethoxazole and sulfapyridine by carbon nanotubes in fixed-bed columns. AU - Tian, Yuan. AU - Gao, Bin. AU - Morales, Veronica L.. AU - Chen, Hao. AU - Wang, Yu. AU - Li, Hui. PY - 2013/3. Y1 - 2013/3. N2 - Sulfamethoxazole (SMX) and sulfapyridine (SPY), two representative sulfonamide antibiotics, have gained increasing attention because of the ecological risks these substances pose to plants, animals, and humans. This work systematically investigated the removal of SMX and SPY by carbon nanotubes (CNTs) in fixed-bed columns under a broad range of conditions including: CNT incorporation method, solution pH, bed depth, adsorbent dosage, adsorbate initial concentration, and flow rate. Fixed-bed experiments showed that pH is a key factor that affects the adsorption capacity of antibiotics to CNTs. The Bed Depth Service Time model describes well the relationship between service time and bed depth and can be used to design appropriate column parameters. During ...

A new two-step purification method of carbon nanotubes (CNTs) involving a microwave treatment followed by a gas-phase chlorination process is reported. The significant advantage of this method over conventional cleaning carbon nanotubes procedures is that under microwave treatment in air, the carbon shells that enc

Electron beam irradiation induced, bending of Iron filled, multiwalled carbon nanotubes is reported. Bending of both the carbon nanotube and the Iron contained within the core was achieved using two approaches with the aid of a high resolution electron microscope (HRTEM). In the first approach, bending of the nanotube structure results in response to the irradiation of a pristine kink defect site, while in the second approach, disordered sites induce bending by focusing the electron beam on the graphite walls. The HRTEM based in situ observations demonstrate the potential for using electron beam irradiation to investigate and manipulate the physical properties of confined nanoscale structures. Copyright 2012 Author(s). This article is distributed under a Creative Commons Attribution 3.0 Unported License. doi:10.1063/1.3688083]. ...

Cognitive deficits and decreased locomotor activity induced by single-walled carbon nanotubes and neuroprotective effects of ascorbic acid Xudong Liu,1,* Yuchao Zhang,1,* Jinquan Li,1 Dong Wang,1 Yang Wu,1 Yan Li,2 Zhisong Lu,3 Samuel CT Yu,4 Rui Li,1 Xu Yang1 1Laboratory of Environmental Biomedicine, Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Science, Central China Normal University, Wuhan, People's Republic of China; 2Chemical and Biomolecular Engineering Department, Hong Kong University of Science and Technology, Hong Kong Special Administrative Region; 3Institute for Clean Energy and Advanced Materials, Southwest University, Chongqing, People's Republic of China; 4Division of Environment, Hong Kong University of Science and Technology, Hong Kong Special Administrative Region *These authors contributed equally to this work Abstract: Single-walled carbon nanotubes (SWCNTs) have shown increasing promise in the field of biomedicine, especially in

Scientists from Tohoku University in Japan have created a new type of energy-efficient flat light source. The light source, which employs carbon nanotubes, has a very low power consumption of around 0.1 Watt for every hours operation.

A 0.4 μm long semiconducting single-walled carbon nanotube is doped into n type by potassium (K) vapor. Electrical measurements of the doped nanotube reveal single-electron charging at temperatures up to 160 K. The K-doped sample manifests as a single quantum dot or multiple quantum dots in series depending on the range of applied gate voltage. This is explained by an inhomogeneous doping profile along the nanotube length. Similarities between K-doped nanotubes and silicon-based quantum dots and the possibility of room-temperature nanotube single-electron transistors are discussed. © 2000 American Institute of Physics ...

This is Erics logbook for Nano Japan project from 2012.6.3-2012.7.27. #contents * Daily schedule [#daily] - 09:00-10:00 Discussion (1) - 10:00-12:00 Solve the problem and write the progress on pukiwiki - 12:00-13:30 Lunch - 13:30-14:30 Discussion (2) - 14:30-16:30 Solve the problem and write the progress on pukiwiki - 16:30-17:30 e-mail report and problems * Goal of the project. [#goal] - Consider the time evolution of a special vibration (radial breathing mode RBM) of a single wall carbon nanotube after applying the local force at t=0 whose functional shape is a Gaussian in the real space. The time evolution is given by differential equations and solution should be given by animation gif generated by Povray and Giam software. (by R. Saito 2012.5.18) - Keywords: Coherent phonon, radial breathing mode, carbon nanotubes, Differential equation, Fourier Transform, Povray and Giam, Mathematica * Schedule for discussion [#discussion] ,Time and Day,Mon,Tue,Wed,Thu,Fri,h ...

This is Erics logbook for Nano Japan project from 2012.6.3-2012.7.27. updated 2012.6.1 by Nugraha #contents * Daily schedule [#daily] - 09:00-10:00 Discussion (1) - 10:00-12:00 Solve the problem and write the progress on pukiwiki - 12:00-13:30 Lunch - 13:30-14:30 Discussion (2) - 14:30-16:30 Solve the problem and write the progress on pukiwiki - 16:30-17:30 e-mail report and problems * Goal of the project. [#goal] - Consider the time evolution of a special vibration (radial breathing mode RBM) of a single wall carbon nanotube after applying the local force at t=0 whose functional shape is a Gaussian in the real space. The time evolution is given by differential equations and solution should be given by animation gif generated by Povray and Giam software. (by R. Saito 2012.5.18) - Keywords: Coherent phonon, radial breathing mode, carbon nanotubes, Differential equation, Fourier Transform, Povray and Giam, Mathematica * Schedule for discussion [#discussion] ,Time and Day,Mon,Tue,Wed,Thu,Fri,h ...

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This paper reports a new hybrid approach toward achieving high volumetric energy and power densities in an electrochemical flow capacitor for grid energy storage. The electrochemical flow capacitor suffers from high self-discharge and low energy density because charge storage is limited to the available surface area (electric double layer charge storage). Here, we examine two carbon materials as conducting particles in a flow battery electrolyte containing the VO 2+/VO 2 + redox couple. Highly porous activated carbon spheres (CSs) and multi-walled carbon nanotubes (MWCNTs) are investigated as conducting particle networks that facilitate both faradaic and electric double layer charge storage. Charge storage contributions (electric double layer and faradaic) are distinguished for flow-electrodes composed of MWCNTs and activated CSs. A MWCNT flow-electrode based in a redox-active electrolyte containing the VO 2+/VO 2 + redox couple demonstrates 18% less self-discharge, 10 X more energy density, and ...

Single Wall Carbon Nanohorns (SWCNHs) are tiny graphene sheets, wrapped to form horn-shaped cones with a half fullerene cap, having 30-50 nm length and 2-5 nm diameter.. Their key characteristic is the tendency to group together and form aggregates (spherical clusters or bundles) like dahlia flowers or buds, having an overall diameter of tens/hundred nm.. Having a basic structure similar to tiny carbon nanotubes, SWCNHs maintain most of the typical properties of nanotubes: high electrical conductivity, high thermal conductivity and easiness of functionalization.. In 2007 Carbonium srl started the successfully production of SWCNHs in a pilot plant, and since January 2013 a new and innovative high yield plant is able to ensure very high production rate and top quality material. With the new plant a fine morphology-selective preparation of single-wall carbon nanohorn is now possible by driving the synthesis condition, so obtaining preponderant seed, dahlia or petal dahlia types or even ...

Temperature dependant electrical behaviors of cellulose based flexible paper transistor were studied. Due to the covalently bonded single walled carbon nanotube into cellulose structure (SCBC), the conduction current of SCBC paper transistor shows two different slopes which is related to the measurement temperature and gate bias voltage of transistor. The electron hopping mechanism among the covalently bonded carbon nanotube in the regenerated cellulose is discussed by increasing measurement temperature of SCBC paper transistor ...

The effect of hybrid carbon fillers of multi-walled carbon nanotubes (CNT) and carbon black (CB) on the electrical and morphological properties of polystyrene (PS) nanocomposites were systematically investigated in microinjection molding (μIM). The polymer nanocomposites with three different filler concentrations (i.e. 3, 5 and 10 wt%) at various weight ratios of CNT/CB (100/0, 30/70, 50/50, 70/30, 0/100) were prepared by melt blending, then followed by μIM under a defined set of processing conditions. A rectangular mold insert which has three consecutive zones with decreasing thickness along the flow direction was adopted to study abrupt changes in mold geometry on the properties of resultant microparts. The distribution of carbon fillers within microparts was observed by scanning electron microscope, which was correlated with electrical conductivity measurements. Results indicated that there is a flow-induced orientation of incorporated carbon fillers and this orientation increased with

As part of the EU SmartVista project to develop a multi-modal wearable sensor for health diagnostics, field-effect transistor (FET) based biosensors were explored, with glucose as the analyte, and carbon nanotubes (CNTs) or monolayer MoS2 as the semiconducting sensing layer. Numerous arrays of CNT-FETs and MoS2-FETs were fabricated by photolithographic methods and packaged as integrated circuits. Functionalization of the sensing layer using linkers and enzymes was performed, and the samples were characterized by atomic force microscopy, scanning electron microscopy, optical microscopy, and electrical measurements. ON/OFF ratios of 102 p-type and , 102 n-type were acheived, respectively, and the work helped survey the viability of realizing such sensors in a wearable device.. ...

Yang, an assistant professor of chemistry at UC Berkeley and a faculty scientist at Lawrence Berkeley National Laboratory (LBNL), chemistry graduate student Joshua Goldberger and their colleagues will publish details of their synthesis in the April 10 issue of Nature. Unlike many other inorganic nanotubes created to date, these nanotubes are perfect single crystals with interesting optical properties carbon nanotubes dont have. And because it is easy to attach organic molecules to gallium nitride surfaces, the hollow tubes hold promise as chemical sensors. Gallium nitride also is a material well known in the semiconductor industry, and is used in many optical, high-temperature and high-voltage electronic circuits. Industrys ability to manipulate gallium nitride means that Yangs development paves the way for relatively inexpensive, large-scale production of high-quality, uniform nanotubes.. The molecular structure of a carbon nanotube is often depicted as rolled chicken wire, though, in fact, ...

BACKGROUND: carbon nanotubes (CNT) can have adverse effects on health. Therefore, minimizing the risk associated with CNT exposure is of crucial importance. The aim of this work was to evaluate if coating multi-walled CNT (MWCNT) with polymers could modify their toxicity, thus representing a useful strategy to decrease adverse health effects of CNT. We used industrially-produced MWCNT uncoated (NT1) or coated (50/50 wt%) with acid-based (NT2) or polystyrene-based (NT3) polymer, and exposed murine macrophages (RAW 264.7 cell line) or Balb/c mice by intratracheal administration. Biological experiments were performed both in vitro and in vivo, examining time- and dose-dependent effects of CNT, in terms of cytotoxicity, expression of genes and proteins related to oxidative stress, inflammation and tissue remodeling, cell and lung tissue morphology (optical and transmission electron microscopy), and bronchoalveolar lavage fluid content analysis. RESULTS: extensive physico-chemical characterization of MWCNT

A molecularly imprinted sol-gel is reported for selective and sensitive electrochemical determination of the drug naloxone (NLX). The sensor was developed by combining molecular imprinting and sol-gel techniques and electrochemically grafting the sol solution onto a functionalized multiwall carbon nanotube modified indium-tin oxide (ITO) electrode. The sol-gel layer was obtained from acid catalyzed hydrolysis and condensation of a solution composed of triethoxyphenylsilane (TEPS) and tetraethoxysilane (TES). The fabrication, structure and properties of the sensing material were characterized via scanning electron microscopy, spectroscopy and electrochemical techniques. Parameters affecting the sensors performance were evaluated and optimized. A sensor fabricated under the optimized conditions responded linearly between 0.0 µM and 12 µM NLX, with a detection limit of 0.02 µM. The sensor also showed good run-to-run repeatability and batch-to-batch performance reproducibility with relative standard

A new potentiometric anionic surfactant sensor was prepared based on multi-walled carbon nanotubes (MWCNTs) used for immobilisation of 1,3-didecyl-2-methylimidazolium tetraphenylborate (DMI-TPB) ion pair as ionophore in the membrane. The investigated sensor showed a Nernstian response for both dodecylbenzenesulphonate and dodecyl sulphate. It responded in 8-10 seconds for each ten-fold concentration change in the range of 1 x 10-7 M to 1 x 10-3 M. The detection limits for DBS and DS were 1 x 10-6 and 2 x 10-7 M, respectively. The sensor revealed a stable potentiometric response and exhibited satisfactory selectivity for DS. The main application of the sensor was in the end-point detection in potentiometric titrations of anionic surfactants. Hyamine 1622, hexadecyltrimethylammonium bromide and cetylpyridinium chloride were tested as potential cationic titrants, and all exhibited analytically usable titration curves with well-defined equivalence point. The operational life time of the sensor ...