Metal-semiconductor sorting of large-diameter single-wall carbon nanotubes by pH-dependent binding to a hydrophobic-interaction adsorbent

A batch adsorption method for sorting large-diameter single-walled carbon nanotubes (SWCNTs) is described that employs a hydrophobic-interaction chromatography (HIC) adsorbent and single nonionic surfactant. The based on the creation of significant differences between metallic semiconductor SWCNTs in their affinity to HIC adsorbent. These are then used efficient separation electronic forms SWCNTs. To gain better understanding mechanism involved, effects various adsorbents under different pH conditions were studied. results obtained demonstrate importance type density hydrophobic functional groups determining relative strength adsorptive interactions also show negatively charged adventitious nanotube hydrophobicity nanotubes. here implemented using widely-available adsorbents, only requires simple titration with HCl or NaOH adjust pH. Furthermore, potentially suitable be performed liquid packed column liquid-phase gradient order achieve high-resolution separations.