Metrology Development Towards Optimizing Single-wall Carbon Nanotube Separations
Speaker: Dr. Christopher Sims, NIST
Host: NOBCChE
Abstract: Full realization of the optical, thermal, or electronic properties of specific single-wall carbon nanotube (SWCNT) (n,m) species requires the isolation of each specie from commercially synthesized mixtures, which contain multiple individual species. Aqueous two-phase extraction (ATPE) is an effective, yet still developing, liquid-phase processing method for these isolations, with control usually achieved by competing two or more surfactants against the nanotube surface. However, evaluating SWCNT extraction conditions has previously required extensive empirical separation experiments. To overcome this barrier, we recently advanced a fluorescence-based spectroscopy method for determining extraction conditions for specific (n,m) species SWCNTs and their enantiomers that does not rely on the performance of separations. This methodology also enables swifter investigation of complicating factors, which are shown to strongly shift the amount of surfactant necessary to cause specific (n,m) extractions. Finally, analytical ultracentrifugation (AUC) measurements are used to probe the surfactant layer compositions on the SWCNTs under extraction conditions. These results provide additional insight into the underlying mechanisms behind ATPE-based SWCNT separations, towards further development and optimization of the ATPE method for isolating individual (n,m) species and their handed enantiomers.
Organic/Inorganic Seminar