Fabrication, Characterization and Its Growth Mechanism of Helical Carbon Nanotubes

: Helical carbon nanotubes were synthesized by a chemical vapour deposition method from both silica aerogels and silica xerogels containing catalysts. The research result shows that the helical carbon nanotubes prepared from the silica aerogels have the following pecularities compared with those from silica xerogels: (1) more degree of graphitization; (2) smaller diameter; (3) better helical shape, namely, the more identical pitch. The peculiar mesoscopic properties of aerogels are responsible for those above pecularties of helical carbon nanotubes prepared from silica aerogels when compared with those from xerogels. What's more, the anisotropy of catalytic activity of the catalyst particles leads to the growth of helical carbon nanotubes.