Supramolecular modification of single-walled carbon nanotubes with a water-soluble triptycene derivative

Supramolecular surface modification of single-walled carbon nanotubes (SWCNTs) using an amphiphilic molecule containing a bent triptycene moiety and a hydrophilic oligo(ethylene glycol) chain is described. The surface modification was realized through the binding of the triptycene moiety onto the sidewall of SWCNTs through a π–π stacking interaction, and the oligo(ethylene glycol) chains extend into the water and act as dispersing agents, thus yielding an aqueous SWCNT dispersion. This dispersion is stable for more than six months and contains a high concentration of SWCNTs. The dispersion was characterized by absorption, fluorescence, and Raman spectroscopy. Based on shape-fitting of SWCNTs and the triptycene moiety, the stacking of triptycene moieties on the SWCNT sidewall shows a nice selectivity for SWCNTs with a diameter of 1.0 nm.