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Chemistry, Chimie, Energy, Énergie, Chemical industry parachemical industry, Industrie chimique et parachimique, Nanotechnologies, nanostructures, nanoobjects, Nanotechnologies, nanostructures, nanoobjets, Physics, Physique, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Matériaux particuliers, Specific materials, Fullerènes et matériaux apparentés; diamants, graphite, Fullerenes and related materials; diamonds, graphite, Graphite, Graphène, Graphene, Modification chimique, Chemical modification, Modificación química, Oxyde, Oxides, Spectrométrie Auger, AES, Spectrométrie Raman, Raman spectroscopy, 8105T, and 8105U

The tetracyanoethylene oxide (TCNEO) functionalization of chemical vapor deposition grown large area graphene and graphite was performed using reaction of TCNEO with carbon surface in chlorobenzene. The successful functionalization has been confirmed by Raman and Auger spectroscopy, and by numerical modeling of the structure and vibrational modes of TCNEO-functionalized graphene. Raman spectra of TCNEO-functionalized graphene and graphite show several groups of lines corresponding to vibrations of attached carbonyl ylide. One of key signatures of TCNEO attachment is the high intensity Raman band at ~1450 cm―1, which represents the C―C=C in plane vibrations in functionalization-distorted graphene. Raman spectra indicate the existence of central (pristine) attachment of TCNEO to graphene surface.

Chemistry, Chimie, Energy, Énergie, Chemical industry parachemical industry, Industrie chimique et parachimique, Nanotechnologies, nanostructures, nanoobjects, Nanotechnologies, nanostructures, nanoobjets, Physics, Physique, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Matériaux particuliers, Specific materials, Fullerènes et matériaux apparentés; diamants, graphite, Fullerenes and related materials; diamonds, graphite, Composé binaire, Binary compounds, Graphène, Graphene, Haute performance, High performance, Alto rendimiento, Lithium, Oxyde de silicium, Silicon oxides, Silice, Silica, Silicium Oxyde, Silicon Oxides, Stockage, Storage, 8105T, 8105U, O Si, and SiO2

In this work, a novel strategy to fabricate ternary MoS2/SiO2/graphene hybrids (MSGs) was developed by incorporating amorphous SiO2 with MoS2 and graphene nanosheets. Serving as anode material in lithium ion batteries, the inert silica component can effectively prevent the pulverization caused by the inner-plane volume expansion of MoS2. It turns out that MSGs with ~40 wt% of SiO2 and ~42 wt% of MoS2 manifest the capacity stabilized at 1060 mAh g―1 for more than 100 cycles at the current density of 0.1 A g―1. Further, this MSG electrode maintains the specific capacity of 580 mAh g 1 at an ultrahigh current density of 8 Ag―1, which outperforms those of the reported MoS2 and MoS2/graphene hybrids.

Chemistry, Chimie, Energy, Énergie, Chemical industry parachemical industry, Industrie chimique et parachimique, Nanotechnologies, nanostructures, nanoobjects, Nanotechnologies, nanostructures, nanoobjets, Physics, Physique, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Matériaux particuliers, Specific materials, Fullerènes et matériaux apparentés; diamants, graphite, Fullerenes and related materials; diamonds, graphite, Méthodes de dépôt de films et de revêtements; croissance de films et épitaxie, Methods of deposition of films and coatings; film growth and epitaxy, Dépôt chimique en phase vapeur (incluant le cvd activé par plasma, mocvd, etc.), Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.), Addition azote, Nitrogen additions, Azote, Nitrogen, Dopage, Doping, Dépendance température, Temperature dependence, Dépôt chimique phase vapeur, CVD, Effet température, Temperature effects, Graphène, Graphene, Matériau dopé, Doped materials, 8105T, 8105U, and 8115G

The N-doped graphene domain is synthesized through co-growth of ammonia and methane by chemical vapor deposition (CVD). Results showed that the nitrogen concentration, defect density, and doping level increased with the decrease in growth temperature. Notably, the position of N1s main peak from X-ray photoelectron spectroscopy (XPS) showed a significant linear blueshift as the temperature decreased, indicating that the main doping nitrogen configuration gradually evolved from pyridinic N to pyrrolic N consistent with the theoretical explanation. In addition, the nitrogen configuration was not influenced by the NH3 flow rate, which was mainly pyridinic N at the high temperature. With increasing NH3 flow rate the redshift of the Raman peak was caused by the elongation of the C―C bonds. This work presented a process to control the predominant bonding configuration of doping nitrogen by mainly choosing the growth temperature through CVD.

Chemistry, Chimie, Energy, Énergie, Chemical industry parachemical industry, Industrie chimique et parachimique, Nanotechnologies, nanostructures, nanoobjects, Nanotechnologies, nanostructures, nanoobjets, Physics, Physique, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure, proprietes mecaniques et thermiques, Condensed matter: structure, mechanical and thermal properties, Equations d'état, équilibres de phases et transformations de phases, Equations of state, phase equilibria, and phase transitions, Transformations de phases particulières, Specific phase transitions, Transformations solide-liquide, Solid-liquid transitions, Surfaces et interfaces; couches minces et trichites (structure et propriétés non électroniques), Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties), Structures de basse dimensionnalité (superréseaux, puits quantiques, multicouches): structure et propriétés non électroniques, Low-dimensional structures (superlattices, quantum well structures, multilayers): structure, and nonelectronic properties, Charbon, Coal, Diffusion RX, X-ray scattering, Fusion, Melting, Goudron, Tar, Microstructure, Poix, Pitch, and Pez

The generalized Warren―Bodenstein's approach of scattering on turbostratic carbon was used to fit the measured X-ray scattering patterns of high melting coal-tar synthetic pitch. A computer program adopting this approach allowing fitting of whole measured scattering powder patterns was written. The program enables refinement of essential physical parameters of turbostratic carbon materials, i.e. the mean lattice parameters ao, co, the mean cluster sizes parallel and perpendicular to the graphitic planes La and Lc, their distributions as well as the mean square atomic displacements 〈ua2〉 and 〈uc2〉. A series of high melting coal-tar synthetic pitch specimens, annealed at different temperatures, was prepared and investigated. In studied samples we observed the increase of the clusters sizes, changes in the mean lattice parameters ao, co, and decay of disorder with increasing annealing temperature.

Chemistry, Chimie, Energy, Énergie, Chemical industry parachemical industry, Industrie chimique et parachimique, Nanotechnologies, nanostructures, nanoobjects, Nanotechnologies, nanostructures, nanoobjets, Physics, Physique, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Nanomatériaux et nanostructures : fabrication et caractèrisation, Nanoscale materials and structures: fabrication and characterization, Matériaux nanocristallins, Nanocrystalline materials, Nanotubes, Caractérisation, Characterization, Caracterización, Modification chimique, Chemical modification, Modificación química, Nanomatériau, Nanostructured materials, Nanotube carbone, Carbon nanotubes, Synthèse, Synthesis, 8107B, and 8107D

Synthesis, characterization, and stabilization tests of two antioxidant (AO) functionalized multi-walled carbon nanotubes (MWCNTs) are presented. Antioxidizing di-tert-butylphenol groups are covalently bonded via two different linkers to the ends and defect sites of MWCNTs. A 40 wt.% degree of chemical functionalization is realized by oxidizing pristine MWCNTs using acid treatment and subsequent catalyzed coupling with the amine-functionalized AOs. Additionally, preparation and full characterization of both AOs, including a five-step synthesis approach with an overall yield of 35%, is described. We show that MWCNT-grafted AOs compounded with isotactic and amorphous polypropylene have moderate or no stabilizing effect against oxidative stress, depending on the method of stabilizer addition. Further, we examine the reason for this weak effect and prove the mechanism of hindered action experimentally.

Chemistry, Chimie, Energy, Énergie, Chemical industry parachemical industry, Industrie chimique et parachimique, Nanotechnologies, nanostructures, nanoobjects, Nanotechnologies, nanostructures, nanoobjets, Physics, Physique, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Generalites, General, Instruments, appareillage, composants et techniques communs à plusieurs branches de la physique et de l'astronomie, Instruments, apparatus, components and techniques common to several branches of physics and astronomy, Techniques, équipements et instruments mécaniques, Mechanical instruments, equipment and techniques, Systèmes et dispositifs micromécaniques, Micromechanical devices and systems, Etat condense: structure, proprietes mecaniques et thermiques, Condensed matter: structure, mechanical and thermal properties, Propriétés thermiques, Thermal properties of condensed matter, Propriétés thermiques des particules fines, nanocristaux et nanotubes, Thermal properties of small particles, nanocrystals, nanotubes, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Nanomatériaux et nanostructures : fabrication et caractèrisation, Nanoscale materials and structures: fabrication and characterization, Nanotubes, Conductivité thermique, Thermal conductivity, Dispositif microélectromécanique, Microelectromechanical device, Dispositivo microelectromecánico, Forêt, Forests, Nanotube carbone, Carbon nanotubes, Nanotube monofeuillet, Singlewalled nanotube, and 8107D

We perform classical molecular dynamics simulations to investigate the mechanical compression effect on the thermal conductivity of the single-walled carbon nanotube (SWCNT) forest, in which SWCNTs are closely aligned and parallel with each other. We find that the thermal conductivity can be linearly enhanced by increasing compression before the buckling of SWCNT forests, but the thermal conductivity decreases quickly with further increasing compression after the forest is buckled. Our phonon mode analysis reveals that, before buckling, the smoothness of the inter-tube interface is maintained during compression, and the inter-tube van der Waals interaction is strengthened by the compression. Consequently, the twisting-like mode (good heat carrier) is well preserved and its group velocity is increased by increasing compression, resulting in the enhancement of the thermal conductivity. The buckling phenomenon changes the circular cross section of the SWCNT into ellipse, which causes effective roughness at the inter-tube interface for the twisting motion. As a result, in ellipse SWCNTs, the radial breathing mode (poor heat carrier) becomes the most favorable motion instead of the twisting-like mode and the group velocity of the twisting-like mode drops considerably, both of which lead to the quick decrease of the thermal conductivity with further increasing compression after buckling.

Chemistry, Chimie, Energy, Énergie, Chemical industry parachemical industry, Industrie chimique et parachimique, Nanotechnologies, nanostructures, nanoobjects, Nanotechnologies, nanostructures, nanoobjets, Physics, Physique, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Matériaux particuliers, Specific materials, Fullerènes et matériaux apparentés; diamants, graphite, Fullerenes and related materials; diamonds, graphite, Effet rayonnement, Radiation effects, Endommagement, Damage, Graphite, and 8105U

Molecular dynamics simulation is used to study radiation damage cascades in graphite. High statistical precision is obtained by sampling a wide energy range (100―2500 eV) and a large number of initial directions of the primary knock-on atom. Chemical bonding is described using the Environment Dependent Interaction Potential for carbon. Graphite is found to exhibit a radiation response distinct from metals and oxides primarily due to the absence of a thermal spike which results in point defects and disconnected regions of damage. Other unique attributes include exceedingly short cascade lifetimes and fractal-like atomic trajectories. Unusually for a solid, the binary collision approximation is useful across a wide energy range, and as a consequence residual damage is consistent with the Kinchin-Pease model. The simulations are in agreement with known experimental data and help to clarify substantial uncertainty in the literature regarding the extent of the cascade and the associated damage.

Chemistry, Chimie, Energy, Énergie, Chemical industry parachemical industry, Industrie chimique et parachimique, Nanotechnologies, nanostructures, nanoobjects, Nanotechnologies, nanostructures, nanoobjets, Physics, Physique, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Etat colloïdal et états dispersés, Colloidal state and disperse state, Etudes physiques et chimiques. Granulométrie. Phénomènes électrocinétiques, Physical and chemical studies. Granulometry. Electrokinetic phenomena, Matériaux poreux, Porous materials, Carbone, Carbon, Carbono, Ion lithium, Lithium ion, Litio ión, Matériau poreux, Porous material, Material poroso, Microparticule, Microparticle, Micropartícula, Microsphère, Microsphere, Microsfera, Particule sphérique, Spherical particle, Partícula esférica, Synthèse, Synthesis, and Síntesis

Novel hierarchical porous carbon microspheres (HPCM) with quantities of micropores and mesopores have been prepared by an alcohol-in-oil emulsion technique using thermoplastic phenolic formaldehyde resin (PF) as the carbon source and copper nitrate (CN) as the template precursor. The effects of CN loading content on the morphology and structure of HPCM were investigated. The results showed that, when the mass ratio of PF and CN is 1:4, the HPCM not only can maintain hierarchical porous microsphere structure, but also display high electrochemical performance with a reversible capacity of 585 mA h g―1 at a current density of 50 mA g―1 and favorable high-rate performance when used as the anode materials for lithium-ion batteries.

Chemistry, Chimie, Energy, Énergie, Chemical industry parachemical industry, Industrie chimique et parachimique, Nanotechnologies, nanostructures, nanoobjects, Nanotechnologies, nanostructures, nanoobjets, Physics, Physique, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Nanomatériaux et nanostructures : fabrication et caractèrisation, Nanoscale materials and structures: fabrication and characterization, Matériaux nanocristallins, Nanocrystalline materials, Nanotubes, Densité, Density, Nanomatériau, Nanostructured materials, Nanotube carbone, Carbon nanotubes, Réseau(arrangement), Arrays, 8107B, and 8107D

A simple process is presented that realizes carbon nanotube (CNT) arrays that meet the process and structure requirements for use in large-scale integrated circuits. Ni particles are formed densely on a conductive TiN layer on SiO2/Si substrates through nucleation and growth by sputtering, which was stopped prior to percolation of the Ni particles. Ni particles as dense as 2.8 × 1012 cm―2 were formed after annealing at 400 °C and chemical vapor deposition (CVD) was carried out at 400 °C by feeding C2H2 at partial pressures as low as 0.13―1.3 Pa so as not to kill the catalyst. Scanning electron microscopy with energy dispersive X-ray spectroscopy revealed the mass density of the arrays to be as high as 1.1 g cm―3. High resolution transmission electron microscopy showed the densely packed CNTs with an average wall number of eight. Atomic force microscopy of the root of the CNT arrays transferred to a SiO2/Si substrate enabled direct counting of individual CNTs, revealing areal densities of CNTs and CNT walls as high as 1.5 × 1012 and 1.2 × 1013 cm―2, respectively. The simple process, using conventional sputtering and CVD apparatus, with carefully engineered conditions offers a route for practical application of CNTs.

Chemistry, Chimie, Energy, Énergie, Chemical industry parachemical industry, Industrie chimique et parachimique, Nanotechnologies, nanostructures, nanoobjects, Nanotechnologies, nanostructures, nanoobjets, Physics, Physique, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure, proprietes mecaniques et thermiques, Condensed matter: structure, mechanical and thermal properties, Structure des liquides et des solides; cristallographie, Structure of solids and liquids; crystallography, Microscopies électronique, ionique et en champ proche, Electron, ion, and scanning probe microscopy, Microscopies en champ proche: microscopies tunnel, à force atomique, optique, à force magnétique, etc, Scanning probe microscopy: scanning tunneling, atomic force, scanning optical, magnetic force, etc, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Matériaux particuliers, Specific materials, Fullerènes et matériaux apparentés; diamants, graphite, Fullerenes and related materials; diamonds, graphite, Epaisseur, Thickness, Graphène, Graphene, Microscopie force atomique, Atomic force microscopy, Rotation, 6837P, 8105T, and 8105U

A precise measurement of graphene thickness is required for the design and development of nano-devices based on the material. Many factors affect this measurement when using scanning tunneling microscope (STM) and atomic force microscope (AFM), including the interaction between the scanning tip and ripples on graphene; such effects have not previously been explored. To investigate this, we measure the sample rotation angle dependence of graphene thickness as determined by contact mode and tapping mode AFM. The graphene thickness as determined by contact mode AFM follows a cosine modulus function of sample rotation angle, while tapping mode AFM reveals a constant graphene thickness, independent of sample rotation angle. For comparison, the AFM torsion signal is measured and follows a sine function of the sample rotation angle. All the measured sample rotation angle dependences can be explained by the interaction between linearly aligned ripples on graphene and the AFM tip in contact with the graphene.

Chemistry, Chimie, Energy, Énergie, Chemical industry parachemical industry, Industrie chimique et parachimique, Nanotechnologies, nanostructures, nanoobjects, Nanotechnologies, nanostructures, nanoobjets, Physics, Physique, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Nanomatériaux et nanostructures : fabrication et caractèrisation, Nanoscale materials and structures: fabrication and characterization, Matériaux nanocristallins, Nanocrystalline materials, Nanotubes, Nanomatériau, Nanostructured materials, Nanotube carbone, Carbon nanotubes, Oxygène, Oxygen, Réduction chimique, Chemical reduction, 8107B, and 8107D

Carbon-based electrocatalysts without metal or with trace metals are potentially effective in delivering robust and efficient oxygen reduction if the active sites are covalently located on a conductive support. In this report, we demonstrate that active sites on carbon nanotubes are created upon oxidation for efficient oxygen reduction to peroxide, whereas the saturation of oxygen groups at graphitic basal planes leads to the loss of electron conduction thereby deteriorates the electrocatalytic activity. Importantly, oxygen groups at different locations (basal/edge sites) and with different structures (C=O, C-OH, COOH, epoxide, etc.) have a significant impact on the oxygen reduction activity. In particular, epoxide bound oxidized carbon shows superior activity among other oxidized carbon nanotubes.

Chemistry, Chimie, Energy, Énergie, Chemical industry parachemical industry, Industrie chimique et parachimique, Nanotechnologies, nanostructures, nanoobjects, Nanotechnologies, nanostructures, nanoobjets, Physics, Physique, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure, proprietes mecaniques et thermiques, Condensed matter: structure, mechanical and thermal properties, Propriétés mécaniques et acoustiques de l'état condensé, Mechanical and acoustical properties of condensed matter, Propriétés mécaniques des solides, Mechanical properties of solids, Fatigue, fragilisation, rupture et fissures, Fatigue, brittleness, fracture, and cracks, Métal transition, Transition elements, Carbone, Carbon, Contrainte résiduelle, Residual stresses, Contrainte thermique, Thermal stresses, Effet contrainte, Stress effects, Fracture, Fractures, Matériau composite, Composite materials, Rupture, Ruptures, Titane, and Titanium

Carbon/carbon(C/C)―Zr―Ti―C composites were fabricated using chemical vapor infiltration and liquid metal infiltration processes. The residual thermal stress (RTS) distribution in the C/C―Zr―Ti―C composites was analyzed by Raman spectroscopy and finite element (FE) calculation. The mechanical behaviors of C/C―Zr―Ti―C composites with three types of carbon fiber preforms were tested. The results showed that there was very high compressive RTS in the fibers and high tensile RTS in the pyrocarbon (PyC) in the marginal region near the carbide. However, in the central region away from the carbide, relatively low compressive stress and tensile RTS were found in the fibers and PyC, respectively. The FE analysis showed that the introduction of carbide into the C/C composites caused a significant increase of the RTS in the PyC near the carbide, indicating that the carbide could change the RTS distribution in C/C composites. Moreover, the distribution of the RTS and its release combined with the carbide distribution and fiber architecture led to variations in the mechanical performance of composites with different preforms.

Chemistry, Chimie, Energy, Énergie, Chemical industry parachemical industry, Industrie chimique et parachimique, Nanotechnologies, nanostructures, nanoobjects, Nanotechnologies, nanostructures, nanoobjets, Physics, Physique, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Nanomatériaux et nanostructures : fabrication et caractèrisation, Nanoscale materials and structures: fabrication and characterization, Matériaux nanocristallins, Nanocrystalline materials, Composé III-V, III-V compound, Compuesto III-V, Fibre carbone, Carbon fibers, Nanomatériau, Nanostructured materials, Nanopointe, Nanotip, Nanopunta, 8107B, and AlN

A facile catalyst-free approach using a simple thermal transport method has been developed to fabricate high-density AlN nanotips on flexible carbon cloth at large scales for use as field emission (FE) emitters. The AlN nanotips exhibit good performance as flexible cold-cathode electron emitters, with a very low turn-on electric field of 1.1―2.3 V μm-1, a low threshold electric field of 1.5―2.5 V μm―1, and a high emission current density. The excellent field emission properties of the AlN nanotips are attributed to the large field enhancement factor of 6895 as well as the combined effect of the tip profile of the AlN nanostructures and the excellent electron transport path of the conductive carbon cloth substrate.

Chemistry, Chimie, Energy, Énergie, Chemical industry parachemical industry, Industrie chimique et parachimique, Nanotechnologies, nanostructures, nanoobjects, Nanotechnologies, nanostructures, nanoobjets, Physics, Physique, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Matériaux particuliers, Specific materials, Fullerènes et matériaux apparentés; diamants, graphite, Fullerenes and related materials; diamonds, graphite, Délaminage, Delamination, Graphite, and 8105U

Surfactant-free Few-Layer-Graphene (FLG) suspensions were prepared by wet media delamination of unmodified isostatic graphite in organic solvents using a shaking plate for fast screening of favorable process parameters and a stirred media mill as a delamination tool. The achieved FLG-concentration was determined by a combination of UV/Vis and Raman spectroscopy. A study of wet delamination for different solvents reveals an analogue behavior as for ultrasound-assisted delaminated samples. In N-methylpyrrolidone as dispersing medium the influence of delamination process parameters on FLG concentration was studied and an optimal set of parameters was found. A comparison between various delamination methods shows that delamination by enhanced shear leads to largest flake structures. The highest value for the FLG production rate (produced mass/time) is obtained in a stirred media mill. The formation of FLG was also proved by measuring the flake thickness by atomic force microscopy (AFM). The FLG percentage derived from AFM agrees well with the results determined by statistical Raman spectroscopic analyses.

Chemistry, Chimie, Energy, Énergie, Chemical industry parachemical industry, Industrie chimique et parachimique, Nanotechnologies, nanostructures, nanoobjects, Nanotechnologies, nanostructures, nanoobjets, Physics, Physique, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure electronique, proprietes electriques, magnetiques et optiques, Condensed matter: electronic structure, electrical, magnetic, and optical properties, Propriétés et matériaux diélectriques, piézoélectriques et ferroélectriques, Dielectrics, piezoelectrics, and ferroelectrics and their properties, Propriétés diélectriques des solides et des liquides, Dielectric properties of solids and liquids, Permittivité (fonction diélectrique), Permittivity (dielectric function), Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Nanomatériaux et nanostructures : fabrication et caractèrisation, Nanoscale materials and structures: fabrication and characterization, Matériaux nanocristallins, Nanocrystalline materials, Nanotubes, Constante diélectrique, Permittivity, Hyperfréquence, Microwave radiation, Mesure hyperfréquence, Microwave measurement, Nanomatériau, Nanostructured materials, Nanotube carbone, Carbon nanotubes, 8107B, and 8107D

Due to their nanoscale, morphology, and chemical composition, the tracking and the quantitative analysis of carbon nanotubes (CNTs) in biological samples still represent huge challenges. A new technique for the quantitative and accurate detection of CNTs in various biological samples at different scales (whole organisms to organs) was developed using amphibian larvae exposed to double-walled CNTs (DWCNTs). This technique is based on the dielectric relaxation of ultra-low volume suspensions under a microwave electromagnetic field. CNT concentrations were consequently extracted from complex permittivity measurements at 5 GHz, making possible to quantitatively assess the animal exposure to CNTs. Our results indicate a detection threshold of 0.02 μg of DWCNTs, which is the lowest achieved in the literature to date.

Chemistry, Chimie, Energy, Énergie, Chemical industry parachemical industry, Industrie chimique et parachimique, Nanotechnologies, nanostructures, nanoobjects, Nanotechnologies, nanostructures, nanoobjets, Physics, Physique, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure electronique, proprietes electriques, magnetiques et optiques, Condensed matter: electronic structure, electrical, magnetic, and optical properties, Propriétés optiques, spectroscopie et autres interactions de la matière condensée avec les particules et le rayonnement, Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation, Emission stimulée, Stimulated emission, Carbone, Carbon, Dégradation, Degradation, Emission gaz, Gas emission, Emisión gas, Emission stimulée, Stimulated emission, Matériau amorphe hydrogéné, and Amorphous hydrogenated material

Mechanically Stimulated Gas Emission (MSGE) spectroscopy was used for investigation into tribochemical reactions and gas emission for four types of amorphous hydrogenated carbon (a-C:H) coatings, which were obtained by either ion beam deposition (IBD) or plasma enhanced chemical vapour deposition (PECVD). The results of statistical analysis, which was employed to identify the components of the emitted gases from the mass-spectrometry data, argue against the hypothesis that considerable amount of CH3 could be present in the emitted gases. For the IBD coatings the main components of the emitted gases were methane and/or argon, whereas for the PECVD coatings they were mainly methane and hydrogen. Noticeable emission of ethane, propane, carbon mono- and dioxides was also detected under sliding of PECVD coatings deposited with the lowest ion energy. While frictional heating has been definitely ruled out as the driving mechanism for MSGE, there are experimental evidences that MSGE has to be associated with structural degradation of the coating.

Chemistry, Chimie, Energy, Énergie, Chemical industry parachemical industry, Industrie chimique et parachimique, Nanotechnologies, nanostructures, nanoobjects, Nanotechnologies, nanostructures, nanoobjets, Physics, Physique, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Matériaux particuliers, Specific materials, Fullerènes et matériaux apparentés; diamants, graphite, Fullerenes and related materials; diamonds, graphite, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Physicochimie de surface, Surface physical chemistry, Graphite, Grafito, Graphène, Graphene, Interface, Interfase, Piégeage, Trapping, Captura, Préparation, Preparation, Preparación, Toile, Fabric, Tela, 8105T, and 8105U

Conductive fabrics are central to smart textiles, a concept that has been gaining attention for applications such as wearable electronics or biosensors. However, current approaches for creating electrically conductive fabrics struggle with issues ranging from low conductivity to skin irritation. The use of graphitic carbon has been investigated as a possible way to impart conductivity to fabrics, yet low loadings, required post-infusion reductions, or the need to remove additives, has limited the application of these materials. In this paper, we introduce an approach that infuses fabric with pristine few layer graphene (FLG)/graphite from natural bulk graphite using an interfacial trapping method. No additives or chemical modification of the graphite is required, and electrical conductivities an order of magnitude higher than previous approaches are achieved.

Chemistry, Chimie, Energy, Énergie, Chemical industry parachemical industry, Industrie chimique et parachimique, Nanotechnologies, nanostructures, nanoobjects, Nanotechnologies, nanostructures, nanoobjets, Physics, Physique, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Nanomatériaux et nanostructures : fabrication et caractèrisation, Nanoscale materials and structures: fabrication and characterization, Matériaux nanocristallins, Nanocrystalline materials, Nanotubes, Points quantiques, Quantum dots, Méthodes de dépôt de films et de revêtements; croissance de films et épitaxie, Methods of deposition of films and coatings; film growth and epitaxy, Electrodépôt, Electrodeposition, electroplating, Graphène, Graphene, Liaison, Binding, Nanomatériau, Nanostructured materials, Nanotube, Nanotubes, Oxyde de titane, Titanium oxide, Titanio óxido, Point quantique, Quantum dots, Préparation, Preparation, Preparación, Réseau(arrangement), Arrays, Titane Oxyde, Titanium Oxides, 8105T, 8105U, 8107B, 8107D, 8107T, 8535B, O Ti, and TiO2

Coaxial heterogeneous graphene quantum dot-sensitized TiO2 nanotube arrays (GQDs/ TNTs) are prepared by a coupling technique of linker molecule binding and electrophoretic deposition (EPD). The silane linker molecules act as a superb medium for integrating GQDs and TNTs by covalent amide linkage, thus preventing GQDs from clogging the tube entrances and forming a uniform GQD layer tightly attached to the inside tube walls during the following EPD process. By adjusting the time of EPD, appropriate thickness of the deposited GQDs in the internal tube walls of TNTs can be controlled. Compared to the pristine TNTs and GQDs/TNTs prepared by the conventional impregnation-precipitation method, the hybrids fabricated by EPD exhibit significantly enhanced photoelectrochemical water-splitting activity and photocatalytic organic dye decomposition performance for their broad photo-absorption range, fast separation of photogenerated charge, and stability.

Chemistry, Chimie, Energy, Énergie, Chemical industry parachemical industry, Industrie chimique et parachimique, Nanotechnologies, nanostructures, nanoobjects, Nanotechnologies, nanostructures, nanoobjets, Physics, Physique, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Nanomatériaux et nanostructures : fabrication et caractèrisation, Nanoscale materials and structures: fabrication and characterization, Nanotubes, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Physicochimie des réactions induites par rayonnements, particules et ultrasons, Physical chemistry of induced reactions (with radiations, particles and ultrasonics), Photochimie, Photochemistry, Matériau composite, Composite material, Material compuesto, Modification chimique, Chemical modification, Modificación química, Nanotube carbone, Carbon nanotubes, Nanotube monofeuillet, Singlewalled nanotube, Nanotubo pared única, Photochimie, Photochemistry, Fotoquímica, and 8107D

The electrochemical polymerization of diphenylamine (DPA) onto electrodes of Pt coated with highly separated metallic (98%) or semiconducting (99%) single-walled carbon nanotubes (SWCNTs) in the presence of H3PW12O40 was performed by cyclic voltammetry in order to obtain composite materials based on polydiphenylamine (PDPA) doped with heteropolyanions of H3PW12O40 and carbon nanotubes. Our data demonstrate that the photoluminescence quenching effect of the PDPA doped with H3PW12O40 heteropolyanions in the presence of SWCNTs is due to the metallic component. Under UV irradiation of SWCNTs highly separated in metallic and semiconducting tubes functionalized with PDPA doped with heteropolyanions of H3PW12O40 new photochemical reactions are evidenced by photoluminescence studies. These reactions lead to a shortening of the macromolecular chain of PDPA. The photochemical process is more intense in the case semiconducting SWCNTs functionalized with PDPA doped with heteropolyanions in comparison to metallic SWCNTs functionalized with PDPA in doped state, it being a consequence of an additional chemical interaction between the DPA dimer doped with H3PW12O40 heteropolyanions and semiconducting SWCNTs.

Chemistry, Chimie, Energy, Énergie, Chemical industry parachemical industry, Industrie chimique et parachimique, Nanotechnologies, nanostructures, nanoobjects, Nanotechnologies, nanostructures, nanoobjets, Physics, Physique, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Nanomatériaux et nanostructures : fabrication et caractèrisation, Nanoscale materials and structures: fabrication and characterization, Matériaux nanocristallins, Nanocrystalline materials, Nanotubes, Nanomatériau, Nanostructured materials, Nanotube carbone, Carbon nanotubes, Nanotube multifeuillet, Multiwalled nanotube, Nanotubo pared múltiple, Nanotube multifeuillets, Oxydation, Oxidation, 8107B, 8107D, Oxyde de graphène, and Graphene oxide

Multiwall carbon nanotubes (MWCNT), generated by catalytic decomposition of methane using a Fe―Mo/MgO catalyst, were subjected to oxidation and exfoliation obtaining aqueous suspensions of few-layer graphene oxides (FLGO). FLGO with different oxidation ratios were obtained using a modified Hummers method by varying the amount of oxidizing agent (KMnO4), followed by ultrasonic exfoliation. The exhaustive characterization of the resulting materials clearly showed surface functional groups evolution during oxidation and structural and morphological changes. Oxidation caused expansion and separation of the graphene layers by oxygenated groups formation and water intercalation. The full opening of the MWCNT resulted in FLGO as carbon nanoribbons and sheets from a KMnO4/ MWCNT ratio of 6.