TEM study of the influence of the catalyst composition on the formation and growth of SWNT
ABSTRACT Different TEM techniques have been combined to study the microscopic mechanisms of SWNTs nucleation and growth. Inspection of samples obtained from the different synthesis routes supports a general phenomenological model which is first described. In this model, formation of the nanotubes proceeds via solvation of carbon into liquid metal droplets, followed by precipitation, at the surface of the particles, of excess carbon in the form of nanotubes. The influence of the composition of the catalyst on the nucleation process was then studied in detail in the case of the Ni -RE (RE = Y, La, Ce...) systems, leading to the identification of the respective roles played by Ni and RE.
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Conference Paper: Introduction to Carbon Nanotubes[Show abstract] [Hide abstract]
ABSTRACT: Carbon nanotubes are remarkable objects that look set to revolutionize the technol. landscape in the near future. Tomorrow's society will be shaped by nanotube applications, just as silicon-based technologies dominate society today. Space elevators tethered by the strongest of cables; hydrogen-powered vehicles; artificial muscles: these are just a few of the technol. marvels that may be made possible by the emerging science of carbon nanotubes. Of course, this prediction is still some way from becoming reality; we are still at the stage of evaluating possibilities and potential. Consider the recent example of fullerenes - mols. closely related to nanotubes. The anticipation surrounding these mols., first reported in 1985, resulted in the bestowment of a Nobel Prize for their discovery in 1996. However, a decade later, few applications of fullerenes have reached the market, suggesting that similarly enthusiastic predictions about nanotubes should be approached with caution. There is no denying, h12/2009
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ABSTRACT: The discovery of carbon nanotubes has opened numerous cutting-edge nanoscale research fields, such as microelectronic devices and biomedical applications. Although pure nanotubes suffice for most purposes, highly purified magnetic carbon nanotubes are more suitable for specialized applications such as gene delivery. The conventional methods of purification are too harsh for nanotubes to retain their magnetic properties, hence it requires loading of magnetic nanoparticles inside individual tubes. In this paper, we propose an innovative purification method to directly extract magnetic carbon nanotubes from arc-discharged single-walled carbon nanotubes. The procedure is easy, and atomic force microscope (AFM) force–distance curve analysis combined with transmission electron microscopy (TEM) images are used to monitor the purification process. The AFM force–distance curves present the forces between the AFM tip and different sample surfaces. By comparing the peak values on a series of curves associated with different sample points, we can directly differentiate the carbon nanotubes retaining magnetic characteristics from other nanotubes after the purification process.Graphical abstractHighlights► Nickel particles enabled magnetic characteristics of carbon nanotube. ► Magnetic carbon nanotubes were purified from arc-discharged source. ► AFM force measurements were compared with JKR model simulation. ► AFM force curve analysis was used to track magnetic carbon nanotubes.Separation and Purification Technology 09/2011; 81(2):174-183. DOI:10.1016/j.seppur.2011.07.025 · 3.09 Impact Factor