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Carbon nanomaterials have attracted enormous attention due to the ever-growing demand for nanoelectronics, energy conversion and storage, and nanosensors. Since the breakthrough in quantitative C 60 synthesis using arc discharge method, low-dimensional allotropes known as carbon nanomaterials, such as carbon nanotubes (CNTs), graphene, etc., have been produced effectively via the arc discharge...
The exfoliation of graphite was investigated in aqueous solutions containing sodium dodecyl sulfate (SDS) as a surfactant. The exfoliation was greatly enhanced near the surface aggregation concentration (SAC) of SDS, 2.6mM, and then decreased for higher SDS contents. However, the flakes exfoliated near the SAC were graphite, whereas graphene was obtained above the critical micelle concentration (CMC)...
A practical approach to bulk-scale graphene-based materials is critically important for their use in the industrial applications. Here, we describe a facile method to prepare graphite oxide (GO) using a Couette–Taylor flow reactor for the oxidation of bulk graphite flakes. We found that the turbulent Couette–Taylor flow in the reactor could be engineered to result in the efficient mixing and mass...
Plasma-based methods were used to graft nitrogen atoms to the hexagonal lattice of vertically aligned carbon nanotubes (v-CNTs). The nitrogen grafting (as pyridinic, pyrrolic and graphitic) was mediated by the creation of defects induced by energetic species present in the nitrogen plasma. We investigated the effect of adding nitrogen atoms via plasma treatment on the electronic properties of both...
In this work, graphene is facilely prepared by direct exfoliation of graphite in aqueous media with the assistance of alkali lignin (AL). The graphite is successfully exfoliated into single- and multi-layer graphene, with about 20% monolayer ones, and the concentration of graphene in the aqueous dispersions can reach 0.65±0.03mgmL −1 . The nanosheets are stabilized in the dispersions owing...
Graphene oxide (GO) and thermally reduced graphene oxide (TRGO) were covalently modified with imidazolium salts through their hydroxyl surface groups. The selective reaction of the –OH groups with p-nitrophenylchloroformate produced labile intermediate organic carbonate functions which were used for the covalent anchoring of a hydroxy-functionalized imidazolium salt. Nanohybrid materials containing...
Microwave heating of an aqueous solution of citric acid, boric acid and urea affords boron-doped carbon dots (C-dots) with ultrafine size (2–6nm) and quasi-spherical shape. The new dots are freely dispersible in water providing stable, optically transparent dispersions with olive-green color. The optical properties of the dots were studied in respect to their photoluminescence and nonlinear optical...
Mesenchymal stem cells (MSCs) preferentially differentiate to osteogenic lineage when cultured on mechanically stiff substrates. However, collagen sponges, clinically approved scaffolds for bone regeneration, provide soft microenvironment to MSCs. Here, we demonstrate that the covalent conjugation of mechanically stiff graphene oxide (GO) flakes to three-dimensional (3D) collagen scaffolds improves...
N-doped carbon aerogels were synthesized by the polycondensation of resorcinol–formaldehyde–melamine mixtures. The prepolymerization of the precursors was determinant for the preparation of meso/macroporous aerogels with varied nitrogen content, regardless the solution pH and M/R molar ratio. The effect was more pronounced at pH 6, as the hydrogels prepared by the one-step route displayed essentially...
We explore different multi-stage and multi-constraint modeling strategies using the Hybrid Reverse Monte Carlo (HRMC) technique to develop realistic models for the amorphous structure of silicon carbide derived-carbon, and investigate the effect of modeling parameters on the development of nano-structural features of the constructed models. It is shown that application of long simulations with slow...
Understanding the nature of phonon transport is of both fundamental and technological importance. In this paper, we demonstrate unambiguous coherent and incoherent phonon transport in 12 C/ 13 C graphene superlattices using large-scale molecular dynamics simulations. Coherent phonon modes preserve their phases as they propagate through multiple interfaces. For these phonons, the superlattice...
The ordered three-dimensional arrays conjugative polyaniline–graphene composites were fabricated through in-situ chemical oxidative polymerization of aniline in the presence of amino-functionalized graphene sheets (AFG), in which polyaniline (PANI) polymerization is initiated by those amino groups on graphene. Therefore, the resulting PANI nanorod arrays are integrated into a large conjugative frame...
First principles calculation reveals that the density functional dispersion correction (DFT-D2) method, instead of generalized gradient approximation (GGA) and local density approximation (LDA), should be appropriate to reflect various properties of W–C interfaces, and that the C/W interface (deposition of C on W) possesses higher interface strength and lower interface energy than the W/C interface...
In this study, we introduce a method for large-area and substrate-independent synthesis of the big-inner-diameter carbon nanotube (BIDI-CNT) thin films by utilizing polydopamine (PDA) as carbon source and ZnO nanorods (NRs) as sacrificing template for the first time. ZnO NRs with hexagonal morphology were coated with PDA films via the ammonium persulfate-induced polymerization of dopamine at neutral...
We report ellipsometric measurement on single walled carbon nanotube (SWCNT) films performed in a large spectral range from 0.07 to 4.97eV. The complex dielectric functions of SWCNTs are correlated to their diameter distribution extracted from transmission electron microscopy. Here we show that the transition energies between Van Hove singularities are directly related to the strong one dimensional...
Progress in the development of carbon nanotubes (CNTs) has stimulated great interest among industries providing new applications. Meanwhile, toxicological evaluations on nanomaterials are advancing leading to a predictive exposure limit for CNTs, which implies the possibility of designing safer CNTs. To pursue safety by design, the redox potential in reactions with CNTs has been contemplated recently...
We demonstrate the direct dry transfer of large area chemical vapor deposition graphene to several polymers (low density polyethylene, high density polyethylene, polystyrene, polylactide acid and poly(vinylidenefluoride-co-trifluoroethylene) by means of only moderate heat and pressure, and the later mechanical peeling of the original graphene substrate. Simulations of the graphene–polymer interactions,...
A cathodic electrochemical method for the exfoliation of graphite to produce hydrogenated graphenic flakes is introduced. The resulting solutions consist of micrometer-sized and predominantly 1–4 layers thick hydrogenated graphenic flakes. In contrast to oxygenation, chemisorption of hydrogen avoids the formation of structural vacancy defects in the exfoliated flakes. Thermal desorption of hydrogen...
We demonstrate the fabrication of flexible micro-supercapacitors based on laser carbonization of polyimide sheets. Localized pulsed laser irradiation rapidly converts the pristine polyimide surface into an electrically conductive porous carbon structure in ambient conditions. Thus, the polyimide sheet acts as both a precursor for the carbonization and a flexible substrate. Effects of various laser...
Hollow carbon nanospheres with uniform morphology and diameter of ∼20nm are synthesized in one step using mannose as the carbon source in non-coordinating solvent. The hollow carbon nanospheres obtained have disordered carbon structure and are rich in oxygenous residues as characterized by Fourier transform infrared spectroscopy, Raman and X-ray photoelectron spectroscopy, and also show multicolor...
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