Characterizing the Effect of Salt and Surfactant Concentration on the Counter-ion Atmosphere around Surfactant Stabilized SWCNTs using Analytical Ultracentrifugation
Stephanie Lam, Ming Zheng, Jeffrey Fagan
Accurate characterization of dispersed-phase nanoparticle properties such as density, size, solvation, and charge is necessary for their utilization in applications such as medicine, energy and materials. Herein, analytical ultracentrifugation is used to quantify bile salt surfactant adsorption on length sorted (7,6) single-walled carbon nanotubes as a function of bulk surfactant concentration and in the presence of varying quantities of a monovalent salt - sodium chloride. We show that AUC with density contrast variation can be used to measure the size of the counter-ion cloud around the surfactant-stabilized SWCNTs through measurement of the interfacial layer of bound surfactant with and without contributions from hydration. The results from these measurements are compared with the trend expected from the change in Debye length as a function of solution ionic strength, and our data is found to agree well with theory above total ionic strengths of approximately 30 mM.
, Zheng, M.
and Fagan, J.
Characterizing the Effect of Salt and Surfactant Concentration on the Counter-ion Atmosphere around Surfactant Stabilized SWCNTs using Analytical Ultracentrifugation, Langmuir, [online], https://doi.org/10.1021/acs.langmuir.6b00605
(Accessed December 4, 2023)