TY - JOUR
T1 - Effect of the tube diameter distribution on the high-temperature structural modification of bundled single-walled carbon nanotubes
AU - Kim, U. J.
AU - Gutiérrez, H. R.
AU - Kim, J. P.
AU - Eklund, P. C.
PY - 2005/12/15
Y1 - 2005/12/15
N2 - We present results of a systematic high-resolution transmission electron microscopy study of the thermal evolution of bundled single-walled carbon nanotubes (SWNTs) subjected to ∼4-h high-temperature heat treatment (HTT) in a vacuum at successively higher temperatures up to 2200°C. We have examined purified SWNT material derived from the HiPCO and ARC processes. These samples were found to thermally evolve along very different pathways that we propose depend on three factors: (1) initial diameter distribution, (2) concomitant tightness of the packing of the tubes in a bundle, and (3) the bundle size. Graphitic nanoribbons (GNR) were found to be the dominant high-temperature filament in ARC material after HTT = 2000°C; they were not observed in any heat-treated HiPCO material. The first two major steps in the thermal evolution of HiPCO and ARC material agree with the literature, i.e., coalescence followed by the formation of multiwall carbon nanotubes (MWNTs). However, ARC material evolves to bundled MWNTs, while HiPCO evolves to isolated MWNTs. In ARC material, we find that the MWNTs collapse into multishell GNRs. The thermal evolution of these carbon systems is discussed in terms of the diameter distribution, nanotube coalescence pathways, C-C bond rearrangement, diffusion of carbon and subsequent island formation, as well as the nanotube collapse driven by van der Waals forces. $ 2005 American Chemical Society.
AB - We present results of a systematic high-resolution transmission electron microscopy study of the thermal evolution of bundled single-walled carbon nanotubes (SWNTs) subjected to ∼4-h high-temperature heat treatment (HTT) in a vacuum at successively higher temperatures up to 2200°C. We have examined purified SWNT material derived from the HiPCO and ARC processes. These samples were found to thermally evolve along very different pathways that we propose depend on three factors: (1) initial diameter distribution, (2) concomitant tightness of the packing of the tubes in a bundle, and (3) the bundle size. Graphitic nanoribbons (GNR) were found to be the dominant high-temperature filament in ARC material after HTT = 2000°C; they were not observed in any heat-treated HiPCO material. The first two major steps in the thermal evolution of HiPCO and ARC material agree with the literature, i.e., coalescence followed by the formation of multiwall carbon nanotubes (MWNTs). However, ARC material evolves to bundled MWNTs, while HiPCO evolves to isolated MWNTs. In ARC material, we find that the MWNTs collapse into multishell GNRs. The thermal evolution of these carbon systems is discussed in terms of the diameter distribution, nanotube coalescence pathways, C-C bond rearrangement, diffusion of carbon and subsequent island formation, as well as the nanotube collapse driven by van der Waals forces. $ 2005 American Chemical Society.
UR - http://www.scopus.com/inward/record.url?scp=30544448341&partnerID=8YFLogxK
U2 - 10.1021/jp0541009
DO - 10.1021/jp0541009
M3 - Article
AN - SCOPUS:30544448341
SN - 1520-6106
VL - 109
SP - 23358
EP - 23365
JO - Journal of Physical Chemistry B
JF - Journal of Physical Chemistry B
IS - 49
ER -