ELECTROANALYSIS, Issue 12 2010
Hyun Yoon
Abstract Mesoporous films of platinized carbon nanotube,zirconia,Nafion composite have been used for the immobilization of tris(2,2,-bipyridyl)ruthenium (II) (Ru(bpy)32+) on an electrode surface to yield a solid-state electrogenerated chemiluminescence (ECL) sensor. The composite films of Pt,CNT,zirconia,Nafion exhibit much larger pore diameter (3.55,nm) than that of Nafion (2.82,nm) and thus leading to much larger ECL response for tripropylamine (TPA) because of the fast diffusion of the analyte within the films. Due to the conducting and electrocatalytic features of CNTs and Pt nanoparticles, their incorporation into the zirconia,Nafion composite films resulted in the decreased electron transfer resistance within the films. The present ECL sensor based on the Pt,CNT,zirconia,Nafion gave a linear response (R2=0.999) for TPA concentration from 3.0,nM to 1.0,mM with a remarkable detection limit (S/N=3) of 1.0,nM, which is much lower compared to those obtained with the ECL sensors based on other types of sol-gel ceramic,Nafion composite films such as silica,Nafion and titania,Nafion. [source]

Improved Detection Limit and Stability of Amperometric Carbon Nanotube-Based Immunosensors by Crosslinking Antibodies with Polylysine

ELECTROANALYSIS, Issue 2 2008
Vito Cataldo
Abstract Amperometric immunosensor configurations featuring covalently bound anti-biotin antibodies (Ab) embedded into a polylysine (PLL)-single walled carbon nanotube (SWCNT) composite layer were evaluated. Assemblies were made by first oxidizing pyrolytic graphite (PG) electrodes to form surface carboxylic acid groups, to which PLL, SWCNTs and anti-biotin were covalently linked. Incorporating SWCNT into PLL-antibody assemblies improved the amperometric detection limit for biotin (Ag) labeled with horseradish peroxidase to 10,fmol mL,1. Anti-biotin embedded into the PLL matrix had improved thermal stability and retained its binding ability for biotin after exposure to temperatures of 42,°C for up to 3 hours, while the noncrosslinked antibody was inactivated at this temperature in several minutes. [source]

Integrated Multifunctional Nanosystems for Medical Diagnosis and Treatment

ADVANCED FUNCTIONAL MATERIALS, Issue 21 2009
*Article first published online: 9 OCT 200, Donglu Shi
Abstract This article provides an overview on the development of integrated multifunctional nanosystems for medical diagnosis and treatment. In particular, a novel system is developed specifically for achieving simultaneous diagnosis and treatment of cancer. Critical issues are addressed on the architecture and assembly of nanocomponents based on medical requirements: targeted in vivo imaging, controlled drug release, localized hyperthermia, and toxicity. Nanotube-based carriers are summarized with surface functionalized properties. Other types of nanocarriers are also included such as super paramagnetic composite nanospheres and biodegradable hydroxylapatite nanoparticles. In addition, polymeric-based nanosystems are introduced with several novel features: they can be bio-dissolved due to environmental pH and temperature fluctuations. The nanocarriers are surface tailored with key functionalities: surface antibodies for cell targeting, anti-cancer drug loading, and magnetic nanoparticles for both hyperthermia and MRI. Future requirements, aims, and trends in the development of multifunctional nanosystems, particularly with intelligent functionalities for fundamental studies, are also provided. [source]

Boron Nanotube,Polymer Composites: Towards Thermoconductive, Electrically Insulating Polymeric Composites with Boron Nitride Nanotubes as Fillers (Adv. Funct.

ADVANCED FUNCTIONAL MATERIALS, Issue 12 2009
Mater.
Composites formed through embedding of high-concentration boron nitride nanotubes in polymers are reported by C. Y. Zhi et al. on page 1857. The composites possess high thermal conductivity, high break-over voltage, low coefficient of thermal expansion, and other favorable properties. These polymeric composites are promising highly thermoconductive electrically insulating materials for a range of applications. [source]

Nanotube,Polymer Composites for Ultrafast Photonics

ADVANCED MATERIALS, Issue 38-39 2009
Tawfique Hasan
Abstract Polymer composites are one of the most attractive near-term means to exploit the unique properties of carbon nanotubes and graphene. This is particularly true for composites aimed at electronics and photonics, where a number of promising applications have already been demonstrated. One such example is nanotube-based saturable absorbers. These can be used as all-optical switches, optical amplifier noise suppressors, or mode-lockers to generate ultrashort laser pulses. Here, we review various aspects of fabrication, characterization, device implementation and operation of nanotube-polymer composites to be used in photonic applications. We also summarize recent results on graphene-based saturable absorbers for ultrafast lasers. [source]

Arrays of Parallel Connected Coaxial Multiwall-Carbon- Nanotube,Amorphous-Silicon Solar Cells

ADVANCED MATERIALS, Issue 38-39 2009
Hang Zhou
Arrays of parallel connected coaxial multiwall-carbon-nanotube,amorphous-silicon solar cells are fabricated. In this configuration, orthogonalization of the directions of light absorption and charge-carrier collection is realized. Under simulated solar illumination (AM 1.5,G), the short-circuit current of our carbon-nanotube enhanced solar cell is ,25% higher than that of the planar cell. [source]

Micropatterned Carbon Nanotube,Gel Composite as Photothermal Material

ADVANCED MATERIALS, Issue 27 2009
Eijiro Miyako
Micropatterned carbon nanotube (CNT),gel composites are prepared using a new and simple method. A micropatterned CNT,gel composite is capable of fast thermal control in microspaces of this composite by an NIR laser. [source]

A Combined Process of In Situ Functionalization and Microwave Treatment to Achieve Ultrasmall Thermal Expansion of Aligned Carbon Nanotube,Polymer Nanocomposites: Toward Applications as Thermal Interface Materials

ADVANCED MATERIALS, Issue 23 2009
Wei Lin
Ultrasmall thermal expansion of aligned carbon nanotube,epoxy composites at temperatures below and above the glass transition is achieved by a novel combined process of in situ functionalization and microwave treatment. Carbon nanotube,polymer interfacial bonding is the key to the reduced thermal expansion, enhanced storage modulus, and improved thermal conductivity. [source]

Reversible Infrared Actuation of Carbon Nanotube,Liquid Crystalline Elastomer Nanocomposites,

ADVANCED MATERIALS, Issue 12 2008
Liqiang Yang
Nanocomposite films comprising polymer-functionalized single-walled carbon-nanotubes (SWNTs) and liquid crystal elastomers (LCEs) show a reversible IR-induced strain (,,30%) at very low SWNT loading levels (,0.2 wt%). SWNTs can efficiently transform absorbed IR light into thermal energy, thereby serving as a nanoscale heat-source and thermal- conduction pathway. The absorbed thermal-energy induced a nematic, isotropic phase-transition, generating a shape change in the nanocomposite film. [source]

Actuating Single Wall Carbon Nanotube,Polymer Composites: Intrinsic Unimorphs,

ADVANCED MATERIALS, Issue 11 2008
Cheol Park
A novel actuating single wall carbon nanotube (SWNT)/polymer composite is reported. It exhibits a large strain (2.6%) at a low driving voltage (<1 MV m,1) while possessing excellent mechanical and thermal properties. The strain energy density is at least an order of magnitude greater than any state-of-the-art polymeric materials reported. The actuating characteristic mainly originates from the electrostrictive contribution, presumably due to interfacial polarization. [source]

A Catalytic Reaction Inside a Single-Walled Carbon Nanotube,

ADVANCED MATERIALS, Issue 8 2008
Hidetsugu Shiozawa
A catalytic reaction inside a single-walled carbon nanotube is demonstrated by using encapsulated ferrocene molecules as precursors. A combined spectroscopic and microscopic study unravels the mechanism of catalytic inner tube growth. This confined process provides for the controlled iron growing of double-walled carbon nanotubes and represents a new route for materials design. [source]

Enhanced Sensitivity of a Gas Sensor Incorporating Single-Walled Carbon Nanotube,Polypyrrole Nanocomposites,

ADVANCED MATERIALS, Issue 12 2004
H. An
A nanocomposite of polypyrrole/carbon nanotubes prepared by in situ chemical polymerization shows improved conductivity of the polypyrrole as compared with its pure form. Its application as a chemical sensor, made using a simple spin-casting technique, shows a drastically increased sensitivity. The Figure shows a field-emission scanning electron microscopy (FE-SEM) image of the SWNT/Ppy nanocomposite. [source]

Modification of Electronic Structures of a Carbon Nanotube by Hydrogen Functionalization

ADVANCED MATERIALS, Issue 24 2002
K.S. Kim
A rigorous method to engineer the electronic structure of carbon nanotubes from metallic to semiconducting is reported (see inside front cover). An intramolecular junction in carbon nanotube is fabricated, where half of the nanotube is masked by a silicon oxide thin film. Functionalization of the nanotube by atomic hydrogen leads to the formation of an intramolecular junction, resulting in clear rectifying behavior at room temperature. This represents an important step towards the practical realization of nanotube-based nanotransistors. [source]

Reinforcement of Calcium Phosphate Cement by Bio-Mineralized Carbon Nanotube

JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 3 2007
Xiupeng Wang
Bio-mineralized carbon natotubes (CNTs) were prepared by soaking carboxyl functionalized CNTs in a simulating body fluid (SBF). A uniform hydroxyapatite layer was precipitated on the outer walls of CNTs after 7 days of soaking. The results showed that, by addition of the as-received CNTs and bio-mineralized CNTs, the compressive strength of the calcium phosphate cement (CPC) increased by 24% and 120%, respectively. The modified interfacial bonding between the bio-mineralized CNTs and CPC accounted for the significant improvement in the mechanical property by addition of the bio-mineralized CNTs as compared with the as-received CNTs. [source]

Crack Toughness Behaviour of Multiwalled Carbon Nanotube (MWNT)/Polycarbonate Nanocomposites

MACROMOLECULAR RAPID COMMUNICATIONS, Issue 15 2005
Bhabani K. Satapathy
Abstract Summary: The morphology and fracture behaviour of polycarbonate (PC)/multiwalled carbon nanotube (MWNT) composites have been studied by AFM and post-yield fracture mechanics. The essential work of fracture (EWF) method has been used to distinguish between two terms representing the resistance to crack initiation and crack propagation. A maximum in the non-essential work of fracture was observed at 2 wt.-% MWNT, demonstrating enhanced resistance to crack propagation compared to pure PC. At 4 wt.-% MWNT, a tough-to-brittle transition has been observed. The time-resolved in-situ strain field analysis revealed that the onset of crack initiation was shifted to a shorter time for nanocomposites with 4 wt.-% MWNT compared to that with 2 wt.-%, and thus explained the existence of a tough-to-brittle transition in these nanocomposites. [source]

Glass Transition Temperature Depression at the Percolation Threshold in Carbon Nanotube,Epoxy Resin and Polypyrrole,Epoxy Resin Composites

MACROMOLECULAR RAPID COMMUNICATIONS, Issue 5 2005
Sophie Barrau
Abstract Summary: The glass transition temperatures of conducting composites, obtained by blending carbon nanotubes (CNTs) or polypyrrole (PPy) particles with epoxy resin, were investigated by using both differential scanning calorimetry (DSC) and dynamical mechanical thermal analysis (DMTA). For both composites, dc and ac conductivity measurements revealed an electrical percolation threshold at which the glass transition temperature and mechanical modulus of the composites pass through a minimum. DC conductivity, ,dc, as a function of the conducting filler concentration of the CNT, (,) and PPy, (,) epoxy resin composites. [source]

Monte Carlo Simulation of ABA Triblock Copolymer Melts Confined in a Cylindrical Nanotube

MACROMOLECULAR THEORY AND SIMULATIONS, Issue 2 2007
Xingqing Xiao
Abstract Monte Carlo simulations were used to identify the microphase morphologies of ABA triblock copolymer melts confined in a cylindrical nanotube. The influences of the volume fraction of mid-block B (fB), the radius of nanotube (R) and the asymmetry of ABA triblock copolymer chain were discussed in detail. When fB varies, a series of double-continuous, three-layer concentric cylinder barrel, porous net, double helixes and the new multiplex structures were observed under different conditions. In addition, the stacked disk, catenoid-cylinder and multi-layer concentric cylinder barrel structures occur in turns at changing R. The relation between circular lamellae period L and layer number Nlayer of concentric cylinder barrel with the increase of R was investigated to further explain the put-off phenomenon of microphase transition of the multi-layer concentric cylinder barrel structures. As for the increase of the asymmetry of ABA triblock copolymer chain, it was concluded that the short AI segments tend to site at the interface between rich A and B circular lamellae. [source]

Isolation of a Small Carbon Nanotube: The Surprising Appearance of D5h(1)-C90,

ANGEWANDTE CHEMIE, Issue 5 2010
Hua Yang
Vollkommen röhrenförmig: Das bislang nicht nachgewiesene höhere Fulleren D5h(1)-C90 (siehe Struktur) wurde als Haupt-C90 -Isomer isoliert, wenn von Sm2O3 -dotierten Graphitstäbchen ausgegangen wurde, und durch eine Röntgenstrukturanalyse charakterisiert. [source]

Innentitelbild: 1,1,8,8-Tetramethyl[8](2,11)teropyrenophane: Half of an Aromatic Belt and a Segment of an (8,8) Single-Walled Carbon Nanotube (Angew. Chem.

ANGEWANDTE CHEMIE, Issue 30 2009
30/2009)
Große, nichtplanare PAHs (polycyclische aromatische Kohlenwasserstoffe) können als diskrete Teilstrukturen der neueren Allotrope von Kohlenstoffnanoröhren betrachtet werden. G.,J. Bodwell et,al. beschreiben in ihrer Zuschrift auf S.,5595,ff. eine kurze Syntheseroute zu einem (2,11)Teropyrenophan mit einem mehrkernigen aromatischen System aus 36 Kohlenstoffatomen, dessen Struktur einem Segment einer einwandigen (8,8)-Kohlenstoffnanoröhre ähnelt. [source]

Carbon Nanotube and Gold-Based Materials: A Symbiosis

CHEMISTRY - A EUROPEAN JOURNAL, Issue 6 2010
Rajpal Singh Dr.
Abstract Carbon nanotubes constitute a novel class of nanomaterials with potential applications in many areas. The attachment of metal nanoparticles to carbon nanotubes is new way to obtain novel hybrid materials with interesting properties for various applications such as catalysts and gas sensors as well as electronic and magnetic devices. Their unique properties such as excellent electronic properties, a good chemical stability, and a large surface area make carbon nanotubes very useful as a support for gold nanoparticles in many potential applications, ranging from advanced catalytic systems through very sensitive electrochemical sensors and biosensors to highly efficient fuel cells. Here we give an overview on the recent progress in this area by exploring the various synthesis approaches and types of assemblies, in which nanotubes can be decorated with gold nanoparticles and explore the diverse applications of the resulting composites. [source]

Carbon Nanotube,Acridine Nanohybrids: Spectroscopic Characterization of Photoinduced Electron Transfer

CHEMISTRY - A EUROPEAN JOURNAL, Issue 15 2009
Nicolas Mackiewicz Dr.
Abstract Change happens: Acridine,carbon nanotube nanohybrids were built (see figure) and their photoinduced electron-transfer properties investigated, showing variable behaviour depending on the acridine partner. Single-walled carbon nanotubes (NT) were covalently functionalized with either 9-phenyl acridine (PhA) or 10-methyl-9-phenyl acridinium (PhMeA+). Absorption and fluorescence properties of acridine derivatives tethered to the nanotubes were studied in homogeneous dispersions. Exciplex emission was observed for NT functionalized with 9-phenylacridine. This phenomenon was attributed to an "intramolecular" interaction between excited phenyl acridine and carbon nanotubes. Interestingly, reverse photoinduced electron transfer from the nanotube to 10-methyl-9-phenylacridinium was detected for the NT-PhMeA+ nanohybrid. This electron transfer led to a strong quenching of the acridinium fluorescence and to the formation of a metastable acridine radical. Evidence for the formation of this radical was obtained by ESR studies. [source]

Self-Assembly and Host,Guest Chemistry of a 3.5-nm Coordination Nanotube

CHEMISTRY - AN ASIAN JOURNAL, Issue 4 2007
Takumi Yamaguchi
Abstract Upon complexation with PdII ions, precisely designed strandlike ligands with two tris(3,5-pyridine) units at both terminals were assembled, with the aid of a linear template molecule, into a discrete tubular complex with a length of 3.5,nm. The high stability and the well-defined structure of the coordination nanotube were revealed by NMR spectroscopy, cold-spray ionization MS, and single-crystal X-ray analysis. Guest lengths were discriminated by the tube: When the association of strandlike guest molecules, in which two biphenylene units are linked with an (OCH2CH2)n linker, were compared, the tube selectively recognized an appropriate guest whose length was comparable to that of the tube. Tetrathiafulvalene (TTF)-terminated linear guests were directly oxidized to TTF2+ in the tube, but reduced stepwise via TTF+, outside the tube. [source]

A New Class of Boron Nanotube

CHEMPHYSCHEM, Issue 17 2009
Jing Wang Dr.
Abstract The configurations, stability and electronic structures of a new class of boron sheet and related boron nanotubes are predicted within the framework of density functional theory. This boron sheet is sparser than those of recent proposals. Our theoretic results show that the stable boron sheet remains flat and is metallic. There are bands similar to the , - bands in graphite near the Fermi level. Stable nanotubes with various diameters and chiral vectors can be rolled from the sheet. Within our study, only the thin (8, 0) nanotube with a band gap of 0.44 eV is semiconducting, while all the other thicker boron nanotubes are metallic, independent of their chirality. It indicates the possibility, in the design of nanodevices, to control the electronic transport properties of the boron nanotube through the diameter. [source]

Light-Driven Thermoelectric Conversion Based on a Carbon Nanotube,Ionic Liquid Gel Composite

CHEMSUSCHEM CHEMISTRY AND SUSTAINABILITY, ENERGY & MATERIALS, Issue 8 2009
Eijiro Miyako Dr.
A photoinduced thermoelectric conversion system based on single-walled carbon nanotube,room temperature ionic liquid composite gels is reported. These new types of gel-based near-infrared laser-driven thermoelectric convertors generate high electrical energy. [source]

Amino Acids Analysis by MALDI Mass Spectrometry Using Carbon Nanotube as Matrix

CHINESE JOURNAL OF CHEMISTRY, Issue 2 2005
Zhang Jing
Abstract Twenty common amino acids have been analyzed successfully by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) using carbon nanotubes as matrix. From the spectra, little or no background interference or fragmentation of the analytes has been observed. This method was also applied to the analysis of amino acid mixture successfully. Carbon nanotubes have some features such as large surface area to disperse the analyte molecules sufficiently and prevent the sample aggregation and strong ultraviolet absorption to transfer energy easily to the analyte molecules. The present method has potential application for the rapid and sensitive analysis of amino acids and their mixture [source]

Tris(2,2,-bipyridyl)ruthenium(II) Electrogenerated Chemiluminescence Sensor Based on Platinized Carbon Nanotube,Zirconia,Nafion Composite Films

Simultaneous Determination of Ascorbic Acid, Dopamine and Uric Acid at Pt Nanoparticles Decorated Multiwall Carbon Nanotubes Modified GCE

ELECTROANALYSIS, Issue 10 2010
Zekerya Dursun
Abstract A modified electrode was fabricated by electrochemically deposition of Pt nanoparticles on the multiwall carbon nanotube covered glassy carbon electrode (Pt nanoparticles decorated MWCNT/GCE). A higher catalytic activity was obtained to electrocatalytic oxidation of ascorbic acid, dopamine, and uric acid due to the enhanced peak current and well-defined peak separations compared with both, bare and MWCNT/GCE. The electrode surfaces were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and electrochemical impedance spectroscopy (EIS). Individual and simultaneous determination of AA, DA, and UA were studied by differential pulse voltammetry. The detection limits were individually calculated for ascorbic acid, dopamine, and uric acid as being 1.9×10,5,M, 2.78×10,8,M, and 3.2×10,8,M, respectively. In simultaneous determination, LODs were calculated for AA, DA, and UA, as of 2×10,5,M, 4.83×10,8,M, and 3.5×10,7,M, respectively. [source]

A New Indirect Electroanalytical Method to Monitor the Contamination of Natural Waters with 4-Nitrophenol Using Multiwall Carbon Nanotubes

ELECTROANALYSIS, Issue 9 2009
Cruz Moraes, Fernando
Abstract The electrochemical detection of the hazardous pollutant 4-nitrophenol (4-NP) at low potentials, in order to avoid matrix interferences, is an important research challenge. This study describes the development, electrochemical characterization and utilization of a multiwall carbon nanotube (MWCNT) film electrode for the quantitative determination of 4-NP in natural water. Electrochemical impedance spectroscopy measurements showed that the modified surface exhibits a decrease of ca. 13 times in the charge transfer resistance when compared with a bare glassy carbon (GC) surface. Voltammetric experiments showed the possibility to oxidize a hydroxylamine layer (produced by the electrochemical reduction of 4-NP on the GC/MWNCT surface) in a potential region which is approximately 700,mV less positive than that needed to oxidize 4-NP, thus minimizing the interference of matrix components. The limit of detection for 4-NP obtained using square-wave voltammetry (0.12,,mol L,1) was lower than the value advised by EPA. A natural water sample from a dam located in São Carlos (Brazil) was spiked with 4-NP and analyzed by the standard addition method using the GC/MWCNT electrode, without any further purification step. The recovery procedure yielded a value of 96.5% for such sample, thus confirming the suitability of the developed method to determine 4-NP in natural water samples. The electrochemical determination was compared with that obtained by HPLC with UV-vis detection. [source]

Using Capsaicin Modified Multiwalled Carbon Nanotube Based Electrodes and p -Chloranil Modified Carbon Paste Electrodes for the Determination of Amines: Application to Benzocaine and Lidocaine

ELECTROANALYSIS, Issue 23 2008
Roohollah
Abstract The utilization of the capsaicin modified carbon nanotube modified basal-plane pyrolytic graphite electrode or p -chloranil modified carbon paste electrodes are presented for the determination of pharmaceutical compounds containing amine functionality, such as benzocaine and lidocaine. In detection of benzocaine at a capsaicin modified electrode, the guaiacol functional group is irreversibly electrochemically oxidized to form the o -quinone derivative which then undergoes nucleophilic attack by the aromatic amine group in benzocaine via a 1,4-Michael addition mechanism forming a catechol-amine adduct. The electrochemically initiated formation of the capsaicin-benzocaine adduct causes a linear decrease in the voltammetric signal corresponding to capsaicin which correlates to the added concentration of benzocaine. [source]

Adsorptive Stripping Voltammetric Determination of 4-Hexylresorcinol in Pharmaceutical Products Using Multiwalled Carbon Nanotube Based Electrodes

ELECTROANALYSIS, Issue 15 2008
Roohollah, Torabi Kachoosangi
Abstract A sensitive electroanalytical method is presented for the determination of 4-hexylresorcinol using adsorptive stripping voltammetry (AdsSV) at a multiwalled carbon nanotube modified basal plane pyrolytic graphite electrode (MWCNT-BPPGE). This method is also extended to the use of a MWCNT modified screen-printed electrode (MWCNT-SPE), thereby demonstrating that this approach can easily be incorporated into a facile and inexpensive electrochemical sensor. [source]