Graphitic structures: From planar to spheres, toroids and helices

Following the discovery of C⁶⁰ (Buckminsterfullerene), nanotubes and graphitic onions, new graphitic-type carbon structures, possessing great stability were predicted theoretically and identified experimentally. The chief characteristic associated with many of these new structures is the presence of pentagons and heptagons in the predominantly hexagonal network leading to positive and/or negative curvature. In this paper, we discuss a range of fullerene-related graphitic sheet structures (e.g. corkscrew-like nanotubes, toroids, round giant fullerenes, etc.) and show that molecular simulation studies based on such curved graphene surfaces are in good agreement with experimental high-resolution transmission electron microscopy (HRTEM) observations. New production methods and possible ways of evaluating nanoscale graphitic structures (surfaces) are discussed. The novel materials may have applications in nanoscale engineering.