One-step sorting of single-walled carbon nanotubes using aqueous two-phase extraction in the presence of basic salts

We demonstrate a simple one-step approach to separate (6,5) CNTs from raw material by using the aqueous two-phase extraction method. To reach this goal, stable and inexpensive K₂CO₃, Na₂CO₃, Li₂CO_3, and K₃PO₄ basic salts are used as modulators of the differentiation process. Under the appropriate parameters, near monochiral fractions become available for straightforward harvesting. In parallel, we show that the isolation process is strongly affected not only by pH but by the inherent nature of the introduced chemical species as well. The results of our study also reveal that the commonly used ingredients of the biphasic system make a strong contribution to the course of the separation by having far from neutral pH values themselves.