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Sequential catalytic growth of carbon nanotubes 
Auteur(s): Jourdain V., Kanzow H, Castignolles M, Loiseau A, Bernier P
(Article) Publié:
Chemical Physics Letters, vol. 364 p.27-33 (2002)
Ref HAL: hal-00656974_v1
Exporter : BibTex | endNote
Résumé: Nanofilaments made of repeated units of multiwall carbon nanotubes (MWCNT) with a metal particle encapsulated at one end were synthesized by thermal chemical vapor deposition (CVD) of methane on Ni-Fe catalysts. The nanofilaments were characterized using scanning electron microscopy (SEM), low- and high-resolution transmission electron microscopy (TEM). A mechanism based on a sequential growth is here proposed to explain the structure. Using the structural information from the TEM micrographs, we demonstrate the existence of two different growth regimes depending on the size of the catalyst particle and estimate the critical carbon concentration in the catalyst particle to initiate the growth. (C) 2002 Elsevier Science B.V. All rights reserved.
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Sequentially grown carbon nanotubes
Auteur(s): Jourdain V., Kanzow H, Castignolles M, Loiseau A, Bernier P
Conference: 16th International Winterschool on Electronic Properties of Novel Materials (KIRCHBERG (AUSTRIA), FR, 2002-03-02)
Actes de conférence: STRUCTURAL AND ELECTRONIC PROPERTIES OF MOLECULAR NANOSTRUCTURES, vol. 633 p.178-181 (2002)
Ref HAL: hal-00656971_v1
Exporter : BibTex | endNote
Résumé: Nanofibers consisting of repeated units of multiwall carbon nanotubes (MWCNT) with a metal particle encapsulated at one end were synthesized by thermal chemical vapor deposition (CVD) of methane/hydrogen on Ni-Fe catalysts. The grown structures were studied by scanning electron microscopy (SEM), low and high-resolution transmission electron microscopy (TEM). Sequential growth is proposed to explain the periodicity of the nanofibers. The nanofibers are broken by sonication into single elementary units open at one end.
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Magnetic interactions in carbon nanostructures
Auteur(s): Goze-Bac C., Latil S, Lauginie P, Jourdain V., Conard J, Duclaux L, Rubio A, Bernier P
(Article) Publié:
Carbon, vol. 40 p.1825-1842 (2002)
Résumé: A review is given of local and non-local magnetic interactions in carbon nanotubes as observed by NMR and EPR. Since reference to graphite and graphene is compulsory, an extended review of the NMR and EPR of graphite and related materials, including GIC, is given. Then EPR, and either static or high-resolution NMR experimental results, both in pure and intercalated MWNT or SWNT, are then reviewed. From high-resolution C-13-NMR in association with a theoretical modelization, it is shown how conducting and semiconducting carbon nanotubes might be discriminated. The benefits of high-resolution NMR for the characterization of carbon nanotube functionalization are described. The strong interdependence of all carbon material studies is clearly highlighted throughout the paper. (C) 2002 Published by Elsevier Science Ltd.
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Macroscopic fibers of carbon nanotubes produced by electric arc discharge
Auteur(s): Kanzow H, Almairac R, Pradeau E, Jourdain V., Tahir S., Bernier P
Conference: 15th International Winter School on Electronic Properties on Novel Materials (KIRCHBERG (AUSTRIA), FR, 2001-03-03)
Actes de conférence: ELECTRONIC PROPERTIES OF MOLECULAR NANOSTRUCTURES, vol. 591 p.568-571 (2001)
Ref HAL: hal-00656976_v1
Exporter : BibTex | endNote
Résumé: Macroscopic fibers of single-wall carbon nanotube bundles were generated in an electric arc experiment in carbon monoxide helium mixtures. The fibers have diameters between 0.1 and 0.5 mm and reached length,, up to 2.5 cm. Scanning and transmission electron microscopy shocked that the fibers consist predominantly of bundles of single wall carbon nanotube and metal particles but very little contamination of other carbon products. X-ray diffraction measurements suggest a preferable orientation of the nanotubes along the fiber axis.
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