Single-walled carbon nanotubes (SWNTs), because of their unique properties, are nearly ideal candidates for components in electronic, optoelectronic and biomedical devices. The fundamental problem of solubilization of SWNTs has been a major impediment for device developments. The hurdle of SWNT solubility, as it relates to development of applications, has been, in principal, overcome by dispersing nanotubes in various solutions through covalent (e.g., organic solvent, polymer or proteins) or noncovalent (e.g., surfactants) bond interactions. However, optimization of solubility is still an on-going activity. Surfactants, including anionic, cationic, nonionic and zwitterionic, are the best choices for avoiding the destruction of SWNTs' electronic properties. This paper reports on a new anionic surfactant agent to solubilize HiPco SWNTs, specifically, sodium bis(2-ethylhexyl) sulfosuccinate (AOT). The amphiphilic nature of AOT, possessing both a hydrophilic head and a hydrophobic double tail, was a key factor in our choice to test its suitability for solubilizing as-prepared suspensions of carbon nanotubes. Two preparative routes, involving purification and non-purification before dispersion, have been exploited. Sonication has been used to disperse SWNTs into AOT aqueous solution. Additionally, high speed centrifugation was performed to remove amorphous and large bundled SWNTs. For characterization of the various carbon nanotube samples, a range of techniques have been utilized, including optical spectroscopy (Raman and UV-Vis-NIR) and AFM and TEM microscopies. We suggest the use of AOT facilitates possible future medical applications in the areas of drug delivery, biosensors and tissue engineering due to its biomimic bilayer lipid membrane architecture.
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