Glycerol‐Based Polyurethane Nanoparticles Reduce Friction and Wear of Lubricant Formulations

Abstract

AbstractThe relative motion of two surfaces in direct contact results in friction and wear. This affects every moving surface, contributing to a quarter of the worldwide energy consumption. The addition of lubricant can reduce friction by separating the surfaces, making more energy‐efficient systems. Lubricants are composed of a base oil and a series of additives. Molecules like glycerol can improve the efficiency of a lubricant system. However, the direct addition of hydrophilic molecules to hydrophobic lubricant oils is challenging due to their poor miscibility. The encapsulation of glycerol, or other hydrophilic additives, in nanocarriers will enable the design of additive systems delivering poorly miscible molecules to the lubricant. Here, glycerol is encapsulated in cross‐linked glycerol nanocapsules. The nanocarrier is dispersed in a lubricant oil and placed between two metal surfaces. The release of the additive, from the nanocarriers, is triggered by the force applied on the nanocarriers by the metal surfaces in contact. The release observed is dependent on the applied force and mechanical properties of the nanocarrier, which can be controlled during the synthesis. The addition of those mechanoresponsive nanocarriers improved the long‐term performance of the lubricant and represents a step toward the reduction of friction between metal–metal contacts.