Nanometer-Thick Fluorinated Ionic Liquid Films as Lubricants in Data-Storage Devices

Media lubricants are critical to the reliability of hard disc drives (HDDs). Ideally, the lubricant should have high thermal stability and low monolayer (ML) thickness. Unfortunately, the state-of-the-art lubricant perfluoropolyether (PFPE) only has limited thermal stability, and its ML is relatively thick due to the polymeric chain structure. In this study, we showed that an ionic liquid (IL) with imidazolium cations and fluorinated anions, [Bmim][FAP], has higher thermal stability than PFPE Z-tetraol based on thermogravimetric analysis (TGA). Moreover, both AFM and friction test results demonstrated that the ML thickness of [Bmim][FAP] is only ∼50% of that of PFPE Z-tetraol, which can be attributed to the smaller molecular size of [Bmim][FAP]. These findings suggest that ILs are promising candidates for the next-generation media lubricants.