Larger diameter selection of carbon nanotubes by two phase extraction using amphiphilic polymeric surfactant.

[Display omitted] • The synthesized POBE-BzE has capability to disperse SWNT in water and p -xylene. • POBE-BzE/SWNT can be extracted to p -xylene from water in diameter selective manner. • Partition coefficients are obtained to explain those diameter selective extractions. Aqueous two-phase extraction is instrumental for obtaining single-walled carbon nanotubes (SWNT) with uniform physical properties. This study reports that a nonionic amphiphilic poly(2-ethyloxazoline)-benzyl ether derivative (POBE-BzE) not only efficiently disperses SWNT in both water and p -xylene, but can also be utilized as a single-surfactant for partitioning SWNT in a water/ p -xylene two-phase extraction in a diameter (d t) selective manner. While individual POBE-BzE/SWNT dispersions exhibit similar photoluminescence positions from the SWNT, d t -dependency occurs according to the solvent. Upon two-phase extraction, a d t SWNT >0.9 nm was mainly extracted to the p -xylene layer, and its partition coefficient was investigated by varying the phase transfer catalyst or sodium chloride amounts, where sodium chloride served as a better transfer agent. The d t selective behavior and its partition coefficient were rationalized by the tight and loose configurations of the BzE moiety in each medium. This novel amphiphilic polymeric surfactant and two-phase extraction may be useful for sorting SWNT and other nanomaterials according to their size. [ABSTRACT FROM AUTHOR]