Thin and thick films of carbon nanotubes find use in diverse application areas such as electrodes for fuel cells, batteries and other electrochemical processes, electron field emitters for flat panel displays and electron beams, heat sinks, and chemically robust filtering membranes.

Previous approaches typically require a suspension in solution, from which the carbon nanotubes are filtered onto a media to the desired thickness. The difficulty lies in the suspension process since carbon nanotubes readily attract each other through van der Waals forces. The nanotubes are then difficult to separate, resulting in a non-uniform dispersion. Adding functional groups to the surface of the carbon nanotubes is one approach to improving solubility, although this usually entails the use of toxic and hazardous reagents. Surfactants is another approach, however both approaches are then followed by prolonged sonication to ensure dispersion. The dispersion also has a limited shelf life.

Isostatic pressing, both cold and hot, has been used to form composites containing carbon nanotubes. We describe an approach of uniaxial die pressing of thin and thick films of carbon nanotubes alone, that is, without any binder. The problem of adhesion of the compact to the upper and lower compression surfaces cannot be resolved using traditional mold-release materials. Instead, a sacrificial layer, such as a thin cellulose paper film, is used, which is subsequently dissolved away, leaving a free-standing pure carbon nanotube film. Changes in bulk electrical resistance during the compaction process are also described.