(484e) Replacing Perfluoropolyether Media Lubricants in Hard-Disk Drives with Nanometer-Thick Ionic Liquid Coatings

Media lubricants are essential to the reliability and function of hard disk drives (HDDs). A good media lubricant has a low coefficient of friction (CoF), low surface tension for uniform surface coverage and self-healing, and can bond with the media surface to promote load-carrying capabilities. Additionally, data storage density can be increased if the lubricant has high thermal stability for heat-assisted magnetic recording (HAMR), and a low monolayer thickness to minimize head media spacing (HMS). However, the traditional HDD lubricants have been functionalized perfluoropolyethers (PFPEs) that lack the thermal stability required to fully enable HAMR technology, and the bulky molecular size of these polymers is a limiting factor in the reduction of the HMS. Ionic liquids (ILs) are promising candidates for this application due to their customizable nature that allows them to be designed with strong tribological properties, as well as their high thermal stabilities and relatively small size. Previous research in our lab has shown that while commercial ILs benefit from the aforementioned characteristics, they struggle to match the bonded thickness, low surface tension, and low CoF that the state-of-the-art PFPEs have achieved. Instead, we demonstrate the successful synthesis of a novel functionalized ionic liquid with highly fluorinated alkyl segments. In addition to the benefits of commercial ILs, our lubricant displays a comparable CoF to the PFPE Ztetraol, but has a lower surface tension and a shorter HMS. These results demonstrate that this novel IL has strong potential to be the next-generation lubricant that enables higher storage-capacity HDDs.