Abstract
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.
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Waltman, R., Khurshudov, A. & Tyndall, G. Autophobic Dewetting of Perfluoropolyether Films on Amorphous-Nitrogenated Carbon Surfaces. Tribology Letters 12, 163–169 (2002). https://doi.org/10.1023/A:1014707207255
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DOI: https://doi.org/10.1023/A:1014707207255