Functional Covalent Chemistry of Carbon Nanotube Surfaces

Peng, Xiaohui; Wong, Stanislaus S.

doi:10.1002/adma.200801464

Cited by 235 publications

(129 citation statements)

References 214 publications

(215 reference statements)

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“…[1][2][3] In the field of biotechnology, CNTs-based biomaterials have also proved quite versatile with applications as diverse as prosthesis, biomolecular recognition and drug delivery systems. 4 Nonetheless, strong intermolecular π-π interactions between the nanotube walls and their high aspect ratio lead to a bundle-like arrangement, which represents a major drawback for their processability and application.…”

Section: Introductionmentioning

confidence: 99%

Poly(ethylene oxide)-b-poly(l-lactide) Diblock Copolymer/Carbon Nanotube-Based Nanocomposites: LiCl as Supramolecular Structure-Directing Agent

et al. 2011

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(2011). Poly(ethylene oxide)-b-poly(l-lactide) Diblock Copolymer/Carbon Nanotube-Based Nanocomposites: LiCl as Supramolecular Structure-Directing Agent. Biomacromolecules, 12 (11),[4086][4087][4088][4089][4090][4091][4092][4093][4094] ABSTRACT: This work relies on the CNT dispersion in either solution or a polymer matrix through the formation of a three component supramolecular system composed of PEO-b-PLLA diblock copolymer, carbon nanotubes (CNTs) and lithium chloride. According to a one-pot procedure in solution, the "self-assembly" concept has demonstrated its efficiency using suspension tests of CNTs.Characterizations of the supramolecular system by photon correlation spectroscopy, raman spectroscopy and molecular dynamics simulations highlight the charge transfer interaction from the CNTs towards the PEO-b-PLLA/LiCl complex. Finally, this concept was successfully extended in bulk (absence of solvent) via melt-processing techniques by dispersing these complexes in a poly(L-Lactide) (PLA) matrix. Electrical conductivity measurements and transmission electron microscopy attested for the remarkable dispersion of CNTs, leading to high-performance PLA-based materials.KEYWORDS: carbon nanotubes, polylactide, poly(ethylene oxide), supramolecular interactions, reactive extrusion, nanocomposites, molecular dynamics simulations Intr oductionOver the last two decades, carbon nanotubes (CNTs) have attracted a special attention to design new nanocomposites due to a unique combination of mechanical, thermal, structural and electrical properties. [1][2][3] In the field of biotechnology, CNTs-based biomaterials have also proved quite versatile with applications as diverse as prosthesis, biomolecular recognition and drug delivery systems. 4 Nonetheless, strong intermolecular π-π interactions between the nanotube walls and their high aspect ratio lead to a bundle-like arrangement, which represents a major drawback for their processability and application. 5 Different strategies aiming at the dispersion of the CNTs in solution or in a polymer matrix have thus been developed. Most of them lie in the non-covalent and covalent functionalizations of CNT surface. 6 However, the supramolecular approach is emerging as a very appealing pathway since it takes advantage of the preservation of the unsaturated conjugated structure. [7][8] This is also supported by a wide range of non-covalent interactions, performed in a reliable and cost-effective manner. For instance, these 3 non-covalently coated CNTs maintain their intrinsic features, namely a robust mechanical behavior, a high electronic conductivity, and their potential biosensing properties.Poly(ethylene oxide) (PEO) belongs to the class of polyethers, exhibiting good solubility in water and organic solvents. As far as their applications are concerned, PEO-containing compounds are used as excipients or as carriers in different biological materials, foods and cosmetics. Moreover, these polymers can develop a specific behavior under varied stimuli such as temperature and salt conce...

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Section: Introductionmentioning

confidence: 99%

Poly(ethylene oxide)-b-poly(l-lactide) Diblock Copolymer/Carbon Nanotube-Based Nanocomposites: LiCl as Supramolecular Structure-Directing Agent

et al. 2011

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“…Carbon nanotubes (CNTs) in their pristine or functionalized forms have been extensively studied due to their remarkable electronic and structural properties, [1][2][3][4] and are widely used in different applications including biomedical sensing, electronics, and charge transport. 5,6 According to tight-binding models, the electronic nature of CNTs is determined by their chirality index (n,m), which defines the folding vector along which a graphite sheet is rolled up in order to form CNTs.…”

Section: Introductionmentioning

confidence: 99%

Spectroscopic signatures of topological and diatom-vacancy defects in single-walled carbon nanotubes

Saidi

Norman

2014

Phys. Chem. Chem. Phys.

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The optical properties, including UV-vis spectra and resonance Raman profiles, of pristine and defected single-walled carbon nanotubes (SWCNTs) are computed using state-of-the-art time-dependent density functional theory (TDDFT) as implemented using the Liouville-Lanczos approach to linear-response TDDFT. The CNT defects were of the form of Stone-Wales and diatom-vacancies. Our results are in very good agreement with experimental results where defects were introduced into a part of defect-free CNTs.In particular, we show that the first and second p-p* excitation energies are barely shifted due to the defects and associated with a relatively small reduction in the maxima of the absorption bands. In contrast, the resonance Raman spectra show close to an order of magnitude reduction in intensities, offering a means to distinguish between pristine and defected SWCNTs even at low defect concentrations.

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“…Two types of competitive interactions influence the dispersibility of the nanotubes: van der Waals forces between CNTs and interactions between CNTs and their surroundings. 8 Several approaches have been taken to improve the stability of a CNT dispersion, for example sonication, 9 functionalization, [10][11][12] use of surfactants, 13-15 among many others. 16,17 The quality of these dispersions are usually quantified by techniques such as absorption, fluorescence and Raman spectroscopies, 18 as well as techniques like transmission electron microscopy (TEM), scanning electron microscopy (SEM) and atomic force microscopy (AFM).…”

Section: Introductionmentioning

confidence: 99%

The effect of different chemical treatments on the structure and stability of aqueous dispersion of iron- and iron oxide-filled multi-walled carbon nanotubes

Moraes¹,

Matos²,

Castro³

et al. 2011

J. Braz. Chem. Soc.

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O efeito de cinco diferentes tratamentos químicos (HNO 3 , H 2 SO 4 , H 2 O 2 , HNO 3 + H 2 SO 4 e HNO 3 + HCl) na homogeneidade, superfície, estrutura e dispersabilidade em água de nanotubos de carbono do tipo multi-paredes preenchidos com ferro ou óxido de ferro foi estudado através de difratometria de raios X (XRD), espectroscopias Raman, UV-Visível e fotoeletrônica de raios X (XPS), análise termogravimétrica (TG) e microscopia eletrônica de varredura (MEV). Os resultados indicaram que os tratamentos são efetivos na remoção de espécies carbonáceas diferentes de nanotubos, presentes na amostra. Com exceção do tratamento com H 2 O 2 , uma boa remoção das espécies contendo metal também foi observada. Além de aumentar a homogeneidade das amostras, os tratamentos também criam grupos carboxílicos e hidroxílicos superficiais, que afetam diretamente a dispersabilidade destas espécies em água. Dispersões estáveis de 2,24 × 10 -1 g L -1 de nanotubos em água foram obtidas após o tratamento com mistura de ácido sulfúrico e ácido nítrico.The effect of five different chemical treatments (HNO 3 , H 2 SO 4 , H 2 O 2 , HNO 3 + H 2 SO 4 and HNO 3 + HCl) on the homogeneity, surface chemistry, structure and dispersibility in water of ironand iron oxide-filled multi-walled carbon nanotube samples was evaluated by X-ray diffractometry (XRD), Raman, UV-Visible and X-ray photoelectron (XPS) spectroscopies, thermogravimetric analysis (TG) and scanning electron microscopy (SEM). The results indicate that the chemical treatments are generally effective in removing non-nanotube carbonaceous species present in the sample. With the exception of the H 2 O 2 treatment, the chemical treatments also offer good removal of free iron-species. Besides the increase in the sample homogeneity, the chemical treatments promoted an increase in the carboxyl and hydroxyl groups at the carbon nanotube surface, what directly affects the dispersibility of these carbon nanotubes in water. Dispersions of 2.24 × 10 -1 g L -1were obtained for the treated samples with a mixture of nitric and sulfuric acid. Keywords: carbon nanotubes, chemical treatment, CVD, nanostructures, nanomaterials IntroductionCarbon nanotubes (CNTs) have received much attention in the last years due to their extraordinary chemical and physical properties, arising from the combination of their typical morphology, structure and size.1 Many different processes have been described for the synthesis of CNTs. Among them, one of the most versatile is the catalytic chemical vapor deposition (CVD), which is based on the decomposition of a carbon source (usually a hydrocarbon) over metal nanocatalysts.2 Usually, the resulting samples are a mixture of CNTs and some impurities, such as other carbonaceous materials (graphite, amorphous carbon, fullerenes, carbon nano-structures, etc.) and the catalyst metal particles.3 These impurities are undesirable for a variety of applications, and different physical and/or chemical treatments are usually performed to remove them. 4 However, it should be noted th...

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Functional Covalent Chemistry of Carbon Nanotube Surfaces

Cited by 235 publications

References 214 publications

Poly(ethylene oxide)-b-poly(l-lactide) Diblock Copolymer/Carbon Nanotube-Based Nanocomposites: LiCl as Supramolecular Structure-Directing Agent

Poly(ethylene oxide)-b-poly(l-lactide) Diblock Copolymer/Carbon Nanotube-Based Nanocomposites: LiCl as Supramolecular Structure-Directing Agent

Spectroscopic signatures of topological and diatom-vacancy defects in single-walled carbon nanotubes

The effect of different chemical treatments on the structure and stability of aqueous dispersion of iron- and iron oxide-filled multi-walled carbon nanotubes

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