Molecular recognition at the nanoscale interface within carbon nanotube bundles

Molecular adsorption onto carbon nanotube surfaces is one of the important topics in the science and technology of carbon nanotubes due to their specific 1D structures with very high aspect ratios. In order to reveal the effect of bundles of single-walled carbon nanotubes (SWNTs) on molecular adsorption at the molecular level, we introduce an HPLC system; namely, we fabricated HPLC columns coated with bundled-SWNTs, isolated-SWNTs or graphene as the stationary HPLC phase, and discovered that polycyclic aromatic hydrocarbons having a one-dimensional shape, such as p-terphenyl and anthracene, exhibit an unusually high affinity to the bundled SWNTs compared to that of the isolated SWNTs. In contrast, no such notable specificity was obtained on a graphene-coated HPLC column. These results indicated that grooves with one-dimensional structures formed by the SWNT-bundles provide a favorable spatial geometry for the specific molecular recognition of aromatic hydrocarbons.