Single carbon nanotube membranes: A well-defined model for studying mass transport through nanoporous materials

This work represents the first study of mass transport phenomena within a n anotube and thus holds promise as; a means of probing the properties of nan otube interiors. Multiwall carbon nanotubes are used as templates to fabric ate single-pore membranes. These membranes are better experimental models f or testing specific predictions of mass transport theories than arrays of n anopores because they require fewer adjustable parameters and they have wel l-defined geometry and chemical structures. Using polystyrene particles as probes, we demonstrate that quantitative information about fundamental mode s of transport, such as hydrodynamic and electrophoretic flow, can be obtai ned using these single-pore membranes. Furthermore, time-resolved mass tran sport measurements can be achieved when the method of Coulter counting is u sed.