Microanotribological behaviors of ionic liquid nanofilms with different functional cations

摘要

Four kinds of molecularly thin films of room temperature ionic liquids (RTILs) with different functional cations were prepared on silicon substrates by dip-coating method. Thermal stability of the RTILs was evaluated using Mettler thermal gravity analysis (TGA) in a nitrogen atmosphere. Chemical compositions of the RTIL nanofilms were examined by means of multifunctional XPS. Nanoscaled adhesion and friction forces between the films and AFM tip were measured by FFM whereas the morphologies of the films were also investigated. Microscaled friction and wear behaviors between the films and Si_3N_4 ball were further measured by the microtribometer. The microanotribological behaviors of different RTIL films were comparatively investigated and discussed in terms of functional cations of the RTILs molecules. Results in this paper revealed that the functional cations of the RTIL films significantly affected their tribological behaviors both in micro- and nanoscales. The corresponding microanotribological mechanism of the tested ultrathin RTIL films under the test conditions was consequently proposed based on the experimental results.