Superlubricity behavior of surfactant micelles at the nanoscale

Abstract

Attaching appropriate molecular layers on the two sliding surfaces is one of the most effective methods to achieve liquid superlubricity at the nanoscale. In this paper, the recent advances in the nanoscale superlubricity achieved by using surfactant micelles in our group was reviewed and discussed. First, the superlubricity conditions for surfactant micelles is established by using atomic force microscopy (AFM), which are the adsorption of surfactant micelles on the two friction surfaces and the formation of the hydration on the exposed headgroups. Second, the nonlinear behavior of dissipation of frictional energy in the superlubricity regime of surfactant micelles is observed and discussed, which is attributed to the elastic deformation of the adsorbed surfactant micelle layer. Third, the fluorinated cationic surfactant micelle layer exhibits the self-recovery behavior after a rupture caused by high normal pressure, and the difference between the rupture and recovery pressures leads to the hysteresis of friction force. Fourth, the superlubricity of layered materials is achieved through attaching sodium dodecyl sulfate micelles on the friction surfaces, which is attributed to the extremely low shear strength between the carbon chain and layered materials. Finally, the problems and future on the superlubricity of surfactant micelles at the nanoscale are discussed.

Keywords

• Superlubricity
• Surfactant micelles
• Nanotribology
• Hydration lubrication
• AFM