Single chain polymer nanoparticles as shear-resilient viscosity modifiers for lubricating oils

Lubricants are crucial to the reduction of erosion and energy loss in systems that include moving surfaces. Two basic requirements for lubricants, viscosity and viscosity-temperature response, are achieved by adding polymers known as viscosity modifiers (VMs). During service, the lubricant's viscosity decreases due to mechanochemically-induced fragmentation of the macromolecules. Herein, we demonstrate how folding the linear polymers into single chain polymer nanoparticles hinders the macromolecule's fragmentation, leading to retention of the lubricant's viscosity properties. Mechanochemical scission in the folded polymer gradually unfolds it, causing the polymer to gain hydrodynamic size and, as a result, these lubricants display permanent viscosity gain. Given the enormous production volume of the lubricant industry, this new class of shear-resilient VMs may lead to considerable financial and environmental benefits.