(163f) The Application and Modeling of Nano-Structured Polymeric Liquid Films in Head-Disk Interface

Chen, H., Carnegie Mellon University
Guo, Q., Carnegie Mellon University
Jhon, M. S., Carnegie Mellon University

Molecularly thin polymeric liquid films, which have been used in high-density data storage devices, are one of the most successful applications of nanoscale confined polymeric liquids. To attain the ultrahigh recording density, the head-disk interface (HDI) spacing is forced to minimize. Improving the lifetime and reliability of hard disk drives with such drastic reductions in the HDI spacing is a great challenge. Above the protective overcoat, perfluoropolyether (PFPE) films are commonly used as lubricants due to their high chemical and thermal stability, low surface tension, and low vapor pressure. The understanding of the static (nanostructure, molecular conformation, and surface morphology, etc.) and dynamic (diffusion, spreading, relaxation, and viscosity, etc.) properties of PFPE nanofilms at the molecular level is critical for optimizing the slider/air/lubricant/overcoat system.

In this poster, the state-of-art study of nano-structured polymeric liquid films from both experimental and simulation will be presented. In the experimental approach, the surface energy, spreading, humidity effect, and relaxation of PFPE films will be covered. Molecular dynamics with a bead-spring model were employed to study the nano-structure, conformation, morphology, self-diffusion coefficient, relaxation time, steady shear viscosity, and complex modulus of molecularly thin polymeric liquid films. Lattice Boltzmann method, was also used to simulate the non-Newtonian flow of polymeric liquid undergoing extremely high shear rate in a confined geometry to model the nearly contact recording in HDI.