Jannis Born, Matteo Manica
ICLR 2022
The dewetting of perfluoropolyether (PFPE) films on amorphous nitrogenated carbon, CNx, is investigated. An optical surface analyzer is used to image perfluoropolyether films on CNx-overcoated magnetic recording disks, An autophobic dewetting transition is observed to result when the PFPE film thickness applied to the disk surface exceeds a critical value. This critical dewetting thickness is linearly dependent on the PFPE molecular weight. Addition of the phosphazine, X-1P, to the PFPE film reduces the critical dewetting thickness compared to that of the neat lubricant. Dewetting in these molecularly-thin PFPE lubricant films is shown to occur at thicknesses where the total disjoining pressure is negative. The impact of this autophobic dewetting on the performance of a head-disk interface is inferred from take-off height measurements conducted as a function of PFPE film thickness. A steep reduction in the slider-disk clearance is observed when the PFPE film is present at thicknesses in excess of the critical dewetting thickness. © 2002 Plenum Publishing Corporation.