A diameter selective fullerene-mediated supramolecular self-assembly motif for single-walled carbon nanotube enrichment

Official URL: https://dx.doi.org/10.1016/j.carbon.2025.120613

Post-synthetic diameter-selective separation of nanotubular structures has relied on exohedral interactions; a diameter-dependent enrichment via endohedral interactions for the purification of bulk single-walled carbon nanotubes (SWCNTs) remains unexplored. This paper describes a novel diameter-selective supramolecular self-assembly motif for nanotube enrichment via fullerene (C60) encapsulation by SWCNTs. C60-grafted silicon wafers and silica particles were used for the diameter-selective self-assembly and enrichment/separation of individualized SWCNTs, respectively. C60 grafting to silica substrates was performed via the addition of azide-terminated silane precursors, followed by the cycloaddition of azides with C60 to azafulleroids. Atomic force microscopy was used to determine the diameter dependency of the method. The diameter-sorted SWCNTs were further characterized via ultraviolet–visible–near-infrared spectroscopy and Raman spectroscopy. The method presented here was found to select SWCNTs with diameters of approximately 1.4–1.7 nm, with a central cavity matched to the diameter of C60. Self-assembly and enrichment/separation of other nanotubular structures are anticipated with this approach.