Influence of Surface Properties on SEM Observation for Carbon Nanotubes with Pretreatment Using Room Temperature Ionic Liquids

Abstract

In this study, we observed hydrophobic or hydrophilic carbon nanotubes (CNTs) by scanning electron microscopy (SEM); the samples were pretreated with room temperature ionic liquids (RTILs) to impart electrical conductivity to their surfaces. When the amount of RTIL on the sample surface and the affinity between the RTIL and sample surface were tuned, suitable electroconductive thin layers were formed on the sample surfaces. The presence of these layers allowed high-quality SEM images to be observed at the nano level. Suitable pretreatments for CNT were achieved using dilute RTIL/ethanol solutions. By optimizing these conditions, we acquired SEM images that were similar in quality to those of samples subjected to the conventional pretreatment of metal sputtering. The highest resolution of the SEM images was less than 30 nm.