Role of surfactant head group and chain length in aqueous lubrication: Steel−steel contact

Abstract

Surfactants are important molecules to decide the lubricating characteristics in aqueous lubrication. In metal working fluids, stabilization of oil droplets in continuous water phase is aided by repulsive force created by surfactants at oil−water interface. Present study explores the possibility of participation of surfactants molecules in lubrication process. Effect of surfactant hydrocarbon chain length and type of head group in aqueous lubrication is explored. Aqueous solutions were prepared using Oleic acid, Tween 20 and Tween 80 surfactants. Goniometer was used for recording surface and interfacial effects of surfactants in water and on steel substrate. Lubricating response of aqueous solutions of surfactants was recorded using Tribometer. Ability of a surfactant to adsorb the steel surface along with longer hydrocarbon chain length is well suited for aqueous lubrication. Solubility of surfactant in water is another important parameter.