One-pass separation of single-wall carbon nanotubes by gel chromatography with a gradient of surfactant concentration

Abstract

We have investigated the diameter-selective separation of carbon nanotubes by one-pass gel chromatography with a gradient of surfactant concentration. The formation of surfactant gradient in a column was successfully measured and is explained by a simple diffusion process even in the gel. We found that the diameter of eluted nanotubes is inversely proportional to the surfactant concentration of eluate. The detailed analysis of the movement of the nanotubes in the gel revealed that the separation mechanism was qualitatively explained by a model based on the trapping and de-trapping events of the nanotube–surfactant micelle on the gel surface,where the probability of the trapping and de-trapping events is proportional to the product of the diameter of the nanotubes and the surfactant concentration.

The role of sodium dodecyl sulfate concentration in the separation of carbon nanotubes using gel chromatography

“…Fig. 5B shows that a correlation between increasing SDS concentration and decreasing nanotube diameter exists, which concurs with previously reported results for elution using a surfactant gradient [15], although it is weak and has considerable scatter. As seen in Fig.…”

“…Similarly, in gel based separations, the concentration of DOC in the eluent has been observed to alter the population of semiconducting species that desorbs from the gel [5,6], and this parameter also influences the adsorption properties of metallic species [14]. However, despite the expected influence of dispersant concentration, with the exception of one study of surfactant gradient effects in a chromatographic column separation [15], the influence of SDS concentration on gel-based separations has been somewhat overlooked in previous reports.…”

Gel Chromatography for Separation of Single-Walled Carbon Nanotubes

“…However, different types of SWNTs can be eluted from the gel when the surfactant concentrations of the two solutions were different. Due to the fact that when different concentrations of the surfactant solutions meet in the gel, the resulting diffusion of surfactants causes local changes in the surfactant concentration on SWNTs, and the adsorption strength of SWNT onto the gel changes according to the surfactant concentration, which leads to the SWNT separation[95].In addition to m/s-SWNT separation, some researchers have analyzed the length distribution of s-SWNTs according to the elution time. In general, shorter s-SWNTs are eluted later.…”

Effect of methanol on surfactants and surfactant–PEO mixtures

“…The aggregation, thermodynamic parameters, and carrier properties of surfactants can be adjusted through inclusion of organic solvents and allows tailoring of surfactant‐based systems for industrial and pharmaceutical applications 6–8 . Mixed surfactants and polymer systems have gained much interest from theoretical as well as practical perspectives due to its diverse applications in different processes such as in separation, dispersion, and solubilization 9–13 . The properties of such kind of systems can be enhanced by the addition of modifiers such as cosurfactants, cosolvents, electrolyte, and ionic liquids 14,15 .…”