COLL 351 |
| T.E. Karis1, B. Marchon1, M.D. Carter1, P.R. Fitzpatrick2, and J. P. Oberhauser2. (1) Hitachi Global Storage Technologies, K74/C1, 650 Harry Rd, San Jose, CA 95120, (2) Department of Chemical Engineering, University of Virginia, 102 Engineers' Way, P.O. Box 400741, Charlottesville, CA 22904 |
| Hydroxyl end groups on perfluoropolyether lubricants physi- and chemi-sorb to the carbon overlayers, thereby preventing spinning off due to centrifugal force and air shear, and are less prone to desorb and accumulate on the magnetic recording slider. However, the otherwise hydrophobic perfluoropolyether is now amphiphilic. This study characterizes the effect of dissolved water on the dielectric and rheological properties of the widely used perfluoropolyether Ztetraol with molecular weight 2000. Up to 10% water dissolved in the polymer, resulting in a transformation from a thick viscous liquid to a transparent viscoelastic gel. The low frequency dielectric loss factor and relative permittivity both increased by an order of magnitude. The implications are that thick films of Ztetraol are subject to variations with environmental relative humidity. Thin films on carbon overcoats may be less susceptible because their end groups are already associated with polar groups on the carbon overcoat. |
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Friction, Lubrication, and Adhesion in Micro- and Nano-Scale Devices
2:00 PM-5:10 PM, Tuesday, March 30, 2004 Marriott -- Orange County 5, Oral
Division of Colloid and Surface Chemistry |