Effects of SiO2 Contaminant on Thermo-Mechanical/Chemical Properties and Lubricity of PFPE Lubricants

Abstract

Using the molecular dynamics (MD) simulations with ReaxFF potential, two different types of PFPE lubricants (Ztetraol and ZTMD) are prepared on a-C film, and SiO₂ particles are adsorbed onto the lubricants at room temperature. From the simulation results, it is observed that the adsorbed SiO₂ particles increase the stiffness of PFPE lubricants leading to less airshear displacement. Since Ztetraol has higher mobility with lower viscosity than ZTMD, the adsorbed SiO₂ particles penetrate deeper into the Ztetraol lubricants. Accordingly, the effect of SiO₂ on the airshear displacement is more obvious to Ztetraol than ZTMD. In addition, the adsorbed SiO₂ particles increase the friction force and the amount of lubricant pick-up during the sliding contact with a nanosized a-C tip.