Polymerization-Induced Self-Assembled Micelles in Oil as Lubricant Additives with Enhanced Tribological Properties

Lubricant additives (LAs) play a crucial role in enhancing the
lubrication performance and durability of oils. However, inorganic nanoparticle
(INP) LAs often encounter challenges related to poor dispersion stability. Here,
polymer micelles were investigated as potential LAs to evaluate their effect on the
lubricating properties of base oils and to explore their friction reduction mechanism.
Through the polymerization-induced self-assembly (PISA) approach, spherical
micelles of the block copolymer poly(lauryl methacrylate)−poly(benzyl methacry-
late) (PLMAx−PBzMAy) were synthesized in oil. These micelles, prepared in situ,
exhibited exceptional dispersion stability surpassing that of inorganic nanoparticles
(SiO2) for over 300 days. Tribological testing revealed that the self-assembled
micelles could disentangle to form a robust layer of a polymeric tribofilm, effectively
preventing wear on the contacting surfaces during friction. Consequently, the load-
bearing capacity was significantly enhanced to 1000 N while maintaining a stable low
coefficient of friction (COF) and low wear rate. This work presents a design protocol for LAs distinguished by their superb
dispersion stability, antifriction, and antiwear characteristics.