Scanning electron microscopy of carbon nanotubes dispersed in ionic liquid: Solvent influence study

In this work we present the results from the use of ionic liquids (ILs) for the sample preparation of carbon nanotubes prior to their characterization by scanning electron microscopy (SEM). Their use implies some advantages such as no damage of the surface of CNTs, the aggregation of the nanoparticles decreases while the number of CNTs individually dispersed increases, therefore, the sample is more representive. The use of ILs avoids the gold sputtering of the sample prior to analysis owing to the conductivity of the ionic liquid medium while increasing the contrast and brightness of the image. A comparative study of the feasibility of three different solvents — namely methanol, surfactant Triton X-100 solution, and imidazolium-based ionic liquid – for the dispersion of MWNTs prior to SEM analysis was carried out. Complementarily, Raman spectroscopy was employed to follow the solubilization of carbon nanotubes within the ionic liquid medium, demonstrating the excellent features of ILs for their use as solvent of CNTs.