Molecular dynamics simulations of the interactions between SWNT and surfactants

To explore the effect of surfactant structure and concentration on the dispersibility of SWNTs in aqueous solutions, the molecular dynamics (MD) simulation was employed to investigate the interactions between the single-walled carbon nanotubes (SWNTs) and four surfactants with and without conjugated structure in water. It is confirmed that surfactants with conjugated structure have a stronger interaction with the SWNT. Aggregate morphologies of surfactants with conjugated structure are different from those without conjugated structure. Multi-layers are prone to form in the former system and the latter one appears semi-micelles on the surface of SWNT. Furthermore, the structures of water and counterion layers around the headgroups are also affected by surfactant structure and concentration. All these changes could present the dispersing ability of surfactants for SWNTs and instruct their applications.

► The interactions between SWNT and surfactants with and without conjugated structure were investigated and compared.
► Different aggregate morphologies on the SWNT were observed.
► The structures of water and counterion layers around the headgroups are affected by surfactant structure and concentration.
► This study could present the dispersing ability of surfactants for SWNTs and instruct their applications.