Graphene as intermediate phase in fullerene and carbon nanotube growth: A Young-Laplace surface-tension model

Growth mechanism of carbon nanotubes using arc-discharge are not fully understood up to now. Here, I show that the formation of carbon nanotubes and fullerene in a pure carbon arc in helium atmosphere may involve graphene bubbles. Electron microscopy shows the graphene bubbles formation at the anode surface. The growth of fullerene and nanotubes can occur from these bubbles due to a large pressure difference (10³ - 10⁴ bar) at the anode interface and can be understood in terms of Young-Laplace law of surface tension. This model can explain the helium pressure dependence of fullerene and carbon nanotube formation.