Lubricant Transfer in Disk Drives

For disk drives with Z-tetraol-coated disks, the ingress of airborne solid particulates into the disk drive was found to result in disk-to-head lubricant transfer. In addition, high humidity was found to enhance the transfer process. Water soluble electrolytes such as alkali halides are most ubiquitous airborne solid particulates. Molecular dynamics calculations were performed to examine (a) the condensation process of H₂O, (b) the effect of alkali halide on the process, (c) the difference between the end-groups of Z-dol and Z-tetraol. It was shown that the OH units of Z-tetraol end-groups would embed themselves into facial layer of water?Celectrolyte droplets, thus encapsulating and stabilizing the droplets, while the OH units of Z-dol would not do so. The lubricant transfer observed uniquely for Z-tetraol-coated disks is attributed to inorganic particulates such as NaCl entering the drive interior, landing on the disk surface, attracting water, and forming Z-tetraol encapsulated water?Celectrolyte droplets. These droplets are viscous and are readily picked up by the slider.