Understanding the partitioning behavior of single-walled carbon nanotubes using an aqueous two-phase extraction system composed of non-ionic surfactants and polymers

In this work, a Pluronic/Dextran system was developed to discover the mechanism of the aqueous two-phase extraction (ATPE) technique, which is widely employed for the sorting of single-walled carbon nanotubes (SWCNTs) and other types of nanomaterials. The role of the phase-forming components and partitioning modulators was comprehensively investigated to gain greater insights into the differentiation process. The obtained results revealed that sodium dodecyl sulfate and sodium dodecylbenzene sulfonate operated as excellent partitioning modulators, enabling the diameter-based sorting of SWCNTs. Additionally, the data strongly suggested that different densities of various SWCNT species drove the movement of SWCNTs in the ATPE system. Consequently, the largest diameter SWCNTs were first influenced by surfactants and, thus, the nanotubes migrated towards a lower density top phase in the following order (7,5) > (8,3) > (6,5) > (6,4). Based on the in-depth analysis of the partitioning system, a mechanism was proposed that described the method in which the popular ATPE separation technique operates.

Automated summary

In this study, a Pluronic/Dextran system was developed to investigate the mechanism of the aqueous two-phase extraction (ATPE) technique for sorting SWCNTs and other nanomaterials. The role of phase-forming components and partitioning modulators was comprehensively studied to gain insights into the differentiation process. The results revealed the effectiveness of sodium dodecyl sulfate and sodium dodecylbenzene sulfonate as partitioning modulators for diameter-based sorting of SWCNTs. Additionally, the study suggested that the density differences of SWCNT species drive their movement in the ATPE system, resulting in a specific order of migration.