Dispersion of single-walled carbon nanotubes in aqueous and organic solvents through a polymer wrapping functionalization

The processing and application of single-walled carbon nanotubes (SWNTs) is limited by their purity and dispersion in most common solvents. Non-covalent polymer wrapping functionalization of SWNTs provides an excellent route to improve their property and thus the dispersion in aqueous and organic solvents occurred simultaneously. This paper reports the purification and a methodology for obtaining dispersion of SWNTs, obtained by arc-discharge, using a biocompatible water soluble polymer which, presumably, wraps around nanotubes. Scanning electron microscope (SEM) and high resolution transmission electron microscope (HR-TEM) were employed to examine the dispersion. UV-Vis-NIR spectroscopy further substantiates the presence of dispersed SWNTs in aqueous solution. Raman spectroscopy reveals the impact of chemical and ultrasonic processing on the structural order of the nanotubes. No trace for structural damage has been observed from the Raman studies and so, our treatment is considered as a physical rather chemical process. The polymer treated tubes become more hydrophilic which was confirmed by contact angle measurement.