An automated gradient titration fluorescence methodology for high-resolution identification of aqueous two-polymer phase extraction conditions for single-wall carbon nanotubes

Published

January 11, 2024

Author(s)

Christopher Sims, Jeffrey Fagan

Abstract

A significant advance in rate and precision of identifying the co-surfactant concentrations leading to differential extraction of specific single-wall carbon nanotube (SWCNT) species in aqueous two-polymer phase extraction (ATPE) experiments is reported. These gains are achieved through continuous titration of co-surfactant and other solution components during automated fluorescence measurements on SWCNT dispersions. The resulting fluorescence versus concentration curves display intensity and wavelength shift transitions traceable to the nature of the adsorbed surfactant layer on specific SWCNT structures at the (n,m) species and enantiomer level at high resolution. The increased precision and speed of the titration method resolve previously invisible complexity in the SWCNT fluorescence during the transition from one surfactant dominating the SWCNT interface to the other, offering insight into the fine details of the competitive exchange process. For the first time, we additionally demonstrate that the competitive process of the surfactant switch is direction independent (reversible) and hysteresis-free; the latter data effectively specifies an upper bound for the time scale of the exchange process. Titration curves are compared to literature results and initial advanced parameter variation is conducted for previously unreasonable to investigate solution conditions.

Citation

Carbon

Volume

219

Pub Type

Journals

Download Paper

https://doi.org/10.1016/j.carbon.2024.118813

Local Download

Keywords

Single-wall carbon nanotube, SWCNT, aqueous two-phase extraction, separation, automation

Citation

Sims, C. and Fagan, J. (2024), An automated gradient titration fluorescence methodology for high-resolution identification of aqueous two-polymer phase extraction conditions for single-wall carbon nanotubes, Carbon, [online], https://doi.org/10.1016/j.carbon.2024.118813, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=956620 (Accessed October 17, 2025)