Carbon nanostructure formation by a reduction of PTFE

Polyyne-containing carbon has been shown to be converted to carbon nanotubes (CNTs) and carbon onions by irradiating an electron beam. The carbon, which is prepared by a reduction of poly (tetrafluoroethylene) (PTFE), is unstable, reactive, and it is used as a precursor to form carbon nanostructrues. A precise transmission-electron-microscope (TEM) observation reveals that some nanostructures, fibrous and spherical, are already formed in the carbon before the irradiation. The nanostructures are assumed to be formed during the reduction of PTFE. The spherical carbon is well graphitized, whereas the fibrous is not. The reduction is carried out at 0 degreesC, which is not enough for the fibrous carbon to be well graphitized. The findings suggest a possibility to form a CNT without an electron beam via a reactive polyyne precursor, and are expected to lead an as-designed CNT synthesis. (C) 2003 Elsevier Science B.V. All rights reserved.