Aqueous suspension of carbon nanotubes via non-covalent functionalization with oligothiophene-terminated poly(ethylene glycol)

A new polymeric amphiphilic molecule for dispersing carbon nanotubes (CNTs) in water, oligothiophene-terminated poly(ethylene glycol) (TN-PEG), was synthesized and its ability to stabilize aqueous CNT dispersions was examined by UV–Vis spectroscopy and transmission electron microscopy. It was observed that the TN-PEGs were strongly adsorbed onto the nanotube surface via a strong π–π interaction, and thus only gentle sonication causes exfoliation of CNT ropes and bundles into well-separated individual objects and small bundles comprising 2–10 tubes. The dispersion ability of the TN-PEGs and the long-term stability of their resulting dispersions were much better than commercial surfactants.