Molecular dynamics simulations of the filling and decorating of carbon nanotubules

Carbon nanotubes (CNTs) have been proposed as excellent materials for the construction of new, precisely tailored ultrafiltration membranes and as promising fibres for the construction of new, stronger composite materials. In this paper classical molecular dynamics simulations are used to investigate the potential use of CNTs in these applications. Functional groups have been covalently attached to the walls of CNTs to provide more extensive interactions between these new fibres and a polymer matrix. We examine the effects of these attachments on the mechanical properties of the tubules. The diffusive molecular flow of methane, ethane and ethylene through single tubules at room temperature are also studied. The simulations predict normal-mode molecular diffusion for methane. However, diffusion that is intermediate between normal-mode and single-file diffusion is predicted for ethane and ethylene. These diffusion results are found to be similar to results predicted for molecular diffusion in zeolites.