Dispersing carbon nanotubes using surfactants

We review the recent advances in dispersing single-wall carbon nanotubes (SWNTs) using amphiphilic surfactants in aqueous solutions. Three aspects are discussed. (1) On the organization of surfactant molecules with SWNTs, new insights at the microscopic level arise from electron microscopy and detailed computer simulation studies. (2) Quantitative measurements, such as molecular interactions between functional groups and SWNTs, the coverage of surfactant on SWNTs in solution, the charge state of the SWNT/surfactant complex, and the degree of dispersion are critical for better understanding dispersion mechanisms and for the further development of dispersion strategies. (3) The thermodynamic driving forces and the role of metastability in the structure of surfactant dispersed SWNT suspensions are analyzed. An outlook on practical and fundamental issues is also presented.