Tribological performance of a surfactant derived from its structure of molecular aggregates in water

Surfactants are promising additives for water-based lubricant surfaces due to their ability to adsorb on metal surfaces and reduce friction under boundary lubrication. In this study, the aggregation behavior of surfactants in aqueous solutions and their effects on friction and anti-wear properties were investigated using sodium 2-hexyldecanoate (2HDNa) as an example. The results revealed that 2HDNa forms vesicles at low concentrations and transits to micelles at higher concentrations. The presence of vesicles led to a significant reduction in friction coefficient and improved anti-wear properties by forming an absorbed film, which was confirmed by neutron reflectometry (NR). The findings of this study emphasize the lubrication and anti-wear performance of vesicles and the importance of surfactant concentration control in water-based lubrication.