Carbon nanotubule formation through polyyne-containing carbon

 
Ayumu Yasuda, Noboru Kawase, and Takeo Matsui
 
Materials Assembling Laboratory,
Kansai Research Institute,
17 Cyudoji-Minami, Shimogyo, Kyoto 600-8813, Japan
 
Polyyne-containing carbon has attracted attention as a new type of carbon material for its unique riple-bond linear structure. It is recognized not only as a new carbon but also as a precursor for the preparation of new types of carbon materials. The polyyne-containing carbon was prepared by electrochemical reduction of a polytetrafluoroethylene (PTFE) film with a reactive anode 1).

 The reduction was carried out by the two-electrode method (anode: Mg, cathode: stainless steel) in tetrahydrofuran, where lithium chloride and iron (II) chloride were dissolved as supporting salts. The PTFE film turned black and the product showed bands at 2100 - 2200 cm-1, which is assigned to the polyyne structure, in the IR and Raman spectrograms. The analysis indicates that the product partially contains the polyyne structure, though it is not a perfect polyyne.

 The cross-section of the film (100 nm thick), which was embedded in an epoxy resin, was heated (800C) and irradiated with electrons (accelerating voltage: 100 kV) in a transmission electron microscope. The electron irradiation lead to the formation of carbon nanotubules 2-4). The obtained nanotubules were a few mm in length, 10 - 50 nm in outer diameter. The number of the graphine layer in the wall was more than 2. This result suggests that the polyyne-containing carbon can be a precursor to form the carbon nanotubules.

 
References

1.    N. Kawase et al., Carbon 36, 1234 - 1235, 1998.
2.    N. Kawase et al., Carbon, in press
3.    N. Kawase et al., Carbon, in press
4.    A. Yasdua et al., Reactive and Functional Polymers, in press.