(272e) Simulation of Corona Formation on Single-Walled Carbon Nanotubes: Ionic Vs. Anionic Surfactants

Single-walled carbon nanotubes (SWCNTs) present a range of properties depending on the specific arrangement of the carbon atoms around the tube axis. This means that any specific application may require a specific structural configuration before widespread use becomes practical. While there have been numerous approaches to synthesize or purify particular nanotube structures, one method has shown has shown a broad range of success. Aqueous two phase partitioning (ATPE) relies on the dispersion of the SWCNTs using various surfactants prior to their introduction to a two-phase system consisting of different polymer solutions. Despite the success exhibited by this approach, the complex interactions between the surfactant corona assembled on the SWCNT and the different solutions are not yet well understood. We use molecular dynamics simulations to examine the assembly of various surfactant molecules on the surface of SWCNTs presenting different diameters. Umbrella sampling simulations shed light on the cooperative nature of surfactant adsorption and allow for the comparison of corona phases consisting of ionic and anionic surfactants. We hope that a better understanding of the corona structure and its dependence on the underlying SWCNT lattice will enable experimentalists to design separation protocols that allow for the sequential extraction of specific SWCNT chiralities.