Dispersion Stability of Single-Walled Carbon Nanotubes Using Nafion in Bisolvent

We have investigated the effect of Nafion and its resulting interaction with single-walled carbon nanotubes (SWCNTs) on the solubility and dispersion properties of SWCNTs in bisolvent. Nafion was used as a polymeric dispersant, providing both electrostatic and steric stabilization in the preparation of a stable and homogeneous suspension of SWCNTs. A correlation was made between solubility and nanodispersion of SWCNTs. Optical spectroscopy showed that the solubility and nanodispersion of SWCNTs increased with the addition of 1-propanol and were greatest at a volume mixture of water/1-propanol of 80/20. We propose a mechanism of improved solubility and nanodispersion of SWCNTs, which is strongly correlated with the adsorption behavior of Nafion on SWCNTs, the surface potential of SWCNTs, and the solubility of Nafion in a liquid medium; amphiphilic Nafion enhances the dispersion of SWCNTs in the mixture of hydrophilic water and relatively hydrophobic 1-propanol.