Simultaneous low friction and ultra-low wear enabled by a 2,5-Furandicarboxylic acid derived bio-based ionic liquid

Bio-based protic ionic liquids (bio-PILs) based on 2,5-Furandicarboxylic acid and polyetheramine was synthesized, which was explored as a neat lubricant and lubricant additive for different alcohols that has different hydroxyl numbers under varied test conditions. Long-term service performance testing showed that the bio-PILs could achieve ultra-low coefficient of friction and wear simultaneously, which decreased coefficient of friction of 95.94% and wear rate of 99.87% compared to dry friction under Si3N4-to-steel tribo-pairs. The distinguished tribological performance is contributed to the bio-PILs can absorb on the rubbing surface and form a lubricating protective film to avoid direct contact of super hard upper Si3N4 ball against lower steel plate. This work presents a facile approach to synthesize high-performance bio-based protic ionic liquids using biomass as bridging agent and provides new insight into the underlying lubricating mechanism, which might help guide the development of novel bio-based lubricants in the future.