Bc. Satishkumar et al., NOVEL EXPERIMENTS WITH CARBON NANOTUBES - OPENING, FILLING, CLOSING AND FUNCTIONALIZING NANOTUBES, Journal of physics. B, Atomic molecular and optical physics, 29(21), 1996, pp. 4925-4934
Carbon nanotubes have been opened using a variety of oxidants includin
g HF/BF3 and OsO4 at room temperature. The opened nanotubes have been
filled with metals such as Ag, Au, Pd and Pt by simple chemical means.
The opened nanotubes, containing a high concentration of acidic funct
ional groups, get covered or closed by reaction with reagents such as
ethylene glycol. The opened nanotubes can also be closed by treatment
with benzene vapour in a reducing atmosphere of argon and hydrogen at
high temperatures. Refluxing carbon nanotubes in a H2SO4-HNO3 mixture
results in a clear colourless solution, which on removal of the Solven
t and excess acid gives a white solid containing functionalized nanotu
bes. Neutralization of the acidic solution by alkali results in the pr
ecipitation of a brown solid containing nanotubes.