C.M. Sims, T. Hicks, J.A. Fagan
National Institute of Standards and Technology,
United States
Keywords: carbon nanotube, CNT, fluorescence, automation, separation, metrology
Summary:
The exceptional optical, thermal, and electronic properties of single-wall carbon nanotubes (SWCNTs) have enabled their use across a broad range of applications, including sensing, photonics, and digital logic. However, the full realization of these properties, and thus, SWCNT technology development, requires the separation of each (n,m) species from commercially synthesized SWCNT mixtures. One effective and scalable approach to isolating these individual (n,m) species, and their handed enantiomers, is surfactant-controlled aqueous two-phase extraction (ATPE), which operates by manipulating differences in solvation energies to isolate target SWCNT species. Despite the utility of the ATPE method for these SWCNT isolations, its vast parameter space, and the multitude of SWCNT (n,m) species, complicates its development and optimization. Towards this, we recently developed an automated fluorescence-based spectroscopy titration method that offers significant advances in the throughput and resolution in determining extraction conditions for specific (n,m) SWCNTs and their (m,n) enantiomers using the ATPE method. Here, we demonstrate the utility of this automated method in rapidly quantifying the effects of various ATPE parameters, such as temperature, surfactant identity and concentration, additive compounds, and combinations of these variables. In addition, we describe how these parameters can be precisely modulated to design new and unique ATPE systems capable of rapidly processing complex, difficult to isolate, multi-specie SWCNT mixtures into their individualized (n,m) components.