Molecular dynamics study on lubricant perfluoropolyether in hard disk driver

The structure of nanoscale lubricant films perfluoropolyether (PFPE) and its mobility on a solid surface are important for the service durability and reliability of the computer head-disk device. Molecular dynamic simulations based on a coarse-grained bead-spring model are adopted to investigate the static properties such as molecular conformation, bead density, end bead density and the dynamic properties such as self-diffusion coefficient as a function of the wall effect and the functionality effect of PFPE films. The simulation results of static properties show that there is a monolayer in surface layer for nonpolar PFPE, while there is a complex layered structure for polar PFPE. While the simulation results of dynamic properties show that the diffusivity of PFPE films is enhanced by wall effect but decreased by the functionality effect.