Phosphonium-organophosphate modified graphene gel towards lubrication applications.

Graphene oil as an emerging lubricant usually did not achieve the desired lubricity due to the poor interface compatibility of graphene and base oil, especially at harsh friction conditions. Herein, a simple mechanical grinding method was first carried out to fabricate trihexyltetradecylphosphonium bis(2-ethylhexyl) phosphate modified graphene gel ([P 66614 [DEHP]-G) for high-performance additive. The as-prepared [P 66614 [DEHP]-G gel shows the extraordinary thermostability, dispersity and tribological properties even at high load and temperature conditions. TOF-SIMS and Raman analysis on the friction interface reveal the existence of multi-film structure which presents good synergistic lubricating effect thereby improving the tribological behaviors. This paper provides a good strategy to fabricate high-performance oil-miscible graphene composites for reducing the friction and wear under harsh conditions. Image 1 • Trihexyltetradecylphosphonium bis(2-ethylhexyl) phosphate modified graphene gel ([P 66614 [DEHP]-G) was successfully prepared with a simple mechanical grinding method. • The [P 66614 [DEHP]-G displays good thermostability and dispersity in nonpolar hydrocarbon oil (150 N). • The [P 66614 [DEHP]-G significantly enhances the load-carrying capacity of base oil and avoids getting stuck of tribo-pairs under high load and temperature conditions. • The excellent lubricity of [P 66614 [DEHP]-G is ascribed to the formation of multi-film structure (tribo-chemical film and graphene deposition film) which displays high thermostability and synergistic lubricating effect. [ABSTRACT FROM AUTHOR]