Electric-Field-Assisted Dip Coating Process of Ultrathin PFPE Lubricant Film for Magnetic Disks

In this paper, the influence of the electric field on the dip-coating process was studied by using lubricants Z-tetraol and TA-30. The electric field assisted the adsorption of both lubricant molecules on the disk surface. This electric field also resulted in an increase in the lubricant film thickness. A positive electric field increased the bonded ratio of the lubricant film. The surface-free energy, step height, and head-disk clearance of the Z-tetraol lubricant film were not affected by the electric field; however, those of the TA-30 lubricant film were improved by the electric field. By molecular dynamics simulation, we confirmed that the molecular mobility of the solution increased by applying the electric field. The lubricant molecules in the solution, which show higher mobility, should have more opportunity to adsorb onto a disk surface. These results show the possibility of reducing the head flying height by the electric-field-assisted dip (EFAD) coating process.