In Situ Observation of Wetting Ionic Liquid on a Carbon Nanotube

The wetting behavior of an ionic liquid (IL) on individual carbon nanotubes (CNTs) was experimentally investigated using in situ electron microscopy. The tip of a single CNT was brought into contact with the surface of the IL using a nanomanipulator. The formation of a meniscus was observed immediately at the contact point. A thin layer of IL also formed simultaneously across the entire CNT surface. The force because of wetting was measured using the Wilhelmy method. After correcting the macroscale classical equations by considering an “apparent” diameter that corresponds well with the thickness of the IL layer on individual CNTs, the experimental data indicated that the wettability of single CNTs with diameters of over 10 nm was subjected to classical laws at the macroscale.