Discriminated structural behaviour of C60 and C70 peapods under extreme conditions
Résumé
We studied structural changes in C60 and C70 peapods - i.e. C60 and C70 chains inserted inside single-walled carbon nanotubes - when submitted to high pressure and temperature conditions. X-ray diffraction experiments showed that while C60 molecules polymerize inside nanotubes at pressures and temperatures consistent with polymerization in bulk C60 phases, no polymerization is observed in C70 peapods, even at pressures and temperatures above the threshold for polymerization in bulk C70. Tubular confinement in the nanotube container prevents the monomers to rearrange in the way needed for polymerization. This result testifies for the strong influence of confinement on the behaviour of C70.