The Geometry of Multishell Nanotubes

Abstract

The main features of the model for carbon nanotubes, prepared by the arc-discharge method, as proposed by Iijima [1], seems to be generally accepted. It is, in particular, unambiguously established that single shell nanotubes consist of a single rolled up graphene sheet forming a seamless cylinder [2– 4], which may be either achiral or chiral. However, the structure of multishell nanotubes is still a matter of some debate, not least because the structure seems to depend on details of the preparation [5] and some variations in struc-ture occur even within the same batch, suggesting that stochastic events may play a role in determining the final structure. It is nevertheless established beyond doubt that the multishell nanotubes are formed by rolled up graphene sheets, some with and others without a chiral component, forming either in part or completely coaxial seamless cylinders [1,6]. In the latter paper it was, moreover, proposed that the cylinders would be faceted by polygonization.