Dynamic simulation of nanoscale lubricant films

Abstract

The nanoscale lubricant film on the disk surface of hard disk drive systems is crucial to the durability of the head–disk interface. In an effort to better understand the performance of these lubricant films, the dynamic behavior of nanoscale, perfluoropolyether lubricant films is analyzed via kinetic Monte Carlo techniques. The lattice-based model, which represents lubricant molecules as simple reactive spheres, specifically includes long-range van der Waals, molecule–surface; interlayer, polar endgroup–endgroup coupling; and polar endgroup–surface coupling interactions. The full-blown three dimensional capabilities of the model allow for a detailed nanostructure analysis of the lubricant films. The model is used to investigate the steady-state surface structure of lubricant films, which describes the dewetting phenomenon and is examined via a function of the interaction parameters, surface loading, and initial surface structure. The evolution of the surface structures is monitored to better understand the mechanism for dewetting or “mogul” dynamics. This modeling effort initializes the groundwork for future research with heterogeneous, polar films. Critical endgroup–endgroup and endgroup–surface interaction energies are identified in terms of film dewetting. A layer-by-layer endgroup orientation analysis provides insight into the surface structure and dewetting.