Effect of surfactants on the degree of dispersion of MWNTs in ethanol solvent

Abstract

The poor dispersibility of multiwalled carbon nanotubes (MWNTs) in organic solvents is a serious obstacle towards development of novel nanomaterials devices. Therefore, the addition of tertiary phase became necessary to promote such dispersion. In the present work, five surfactants were tested to evaluate the degree of dispersion of MWCNTs in Ethanol: Sodium Dodecyl Sulfate (SDS), Triton X-100, Span-60, Pluronic F-127 and Cetyl trimethyl Ammonium Bromide (CTAB). The concentration of MWNTs was kept constant to be around 1 g/l. Dispersion degree of surfactant coated MWNTs has been characterized with UV–vis spectroscopy, Zeta Potential (ξ-potential) and Transmission Electron Microscopy (TEM). According to ξ-potential, the SDS was found to enhance the MWNTs dispersibility in ethanol solvent compared to the other surfactants. The degree of dispersion was found in ascending order as follows: CTAB < Pluronic < Triton X-100< Span-60< SDS. The mechanism of the degree dispersion of MWNTs will be explained and proposed according to the functional groups and the geometry of such surfactant. The FTIR analysis and SEM observations are in good concordance with ξ-potential results.