We simulate the generation of an adsorbed layer of C18 fatty acids on iron-based surfaces.

In situ adsorption followed by XPS analysis is performed to validate the model.

When the degree of oxidation or hydroxylation increases, the reactivity between C18 fatty acids and the surface decreases.

Steric effects induced by unsaturation prevent the formation of a well-arranged monolayer.

Tribotests and molecular dynamic simulation show that stearic acid has the best tribological behavior on iron oxide surface.