Selective self-assembly of single walled carbon nanotubes in long steel tubing for chemical separations

This paper reports the scaled-up self-assembly of single walled carbon nanotubes (SWCNTs) on the inside wall of a long silica-lined steel capillary tubing for applications such as chemical processing and separations. A unique one step self-assembly process has been developed and the effect of the substrate on the morphology of the CVD growth has been studied. With the aerosol spray of an ethanolic solution consisting of dissolved cobalt and molybdenum as metal catalysts and co-catalysts respectively, the catalyst was generated and activated in situ inside the interior of the tubing, in parallel with the synthesis of SWCNTs, thus eliminating the need to coat the substrate with the catalyst prior to the synthesis of the nanotubes. The presence of a silica layer on the steel tubing was found to be critical for the formation of SWCNTs. Gas chromatographic separation of aromatic compounds is demonstrated on the capillary tube.