Impact of Sodium Dodecyl Sulfate Sonochemical Byproducts on the Gel-Based Purification of Single-Walled Carbon Nanotubes

The chirality-specific study of single-walled carbon nanotubes (SWCNTs) necessitates their solution-phase processing with tip-horn sonication in the presence of a stabilizing surfactant such as sodium dodecyl sulfate (SDS), a process that has been shown to introduce sonochemical side-products such as dodecanol, dodecanal, and dodecene. This work employs single-column interactions within the overloading regime to quantitatively assess the impacts of dodecanol, dodecanal, and dodecene on the ability to purify SWCNTs using Sephacryl S-200 hydrogel. Increasing concentrations of each additive caused a corresponding decrease in the number of SWCNTs adsorbed to the gel, with a 50% reduction in SWCNT uptake realized at 0.75–1.00 mM for all three additives. Per-chirality adsorption selectivity was unaffected by relatively low additive concentration, but it was significantly hindered nearer the solubility limit of each additive. Elution efficiency from each gel was independent of additives, additive concentration, and SWCNT chirality. Mechanistically, these findings suggest the integration of each additive within the micelle structure of SDS. While the concentration of each additive introduced during tip-horn sonication is insufficient to impact gel-based SWCNT purification, the presence of dodecanol impurities within as-purchased SDS have the potential to significantly impact the purification outcome, suggesting that future studies of gel-based SWCNT purification should be carried out with SDS purified by recrystallization.