The interaction energy between a graphene sheet and a catalytic substrate-supported metal cluster has been studied by classical molecular dynamics simulation, in the wider context of a multi-scale modelling investigation of the growth process of single wall carbon nanotubes (SW-NTs). The contact angle of the metal cluster on the substrate is proportional to the binding energy of the potential function representing the interaction between the metal cluster and the substrate, and the total interaction energy between the metal cluster and the graphene sheet depends on contact angle. However, the interaction energy per unit area was found to be 1.0 eV angstrom(-2) (16.03 j m(-2)), independent of the contact angle, using Ni as catalyst. (c) 2006 Elsevier B.V. All rights reserved.