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Direct Measurement of Plowing Friction and Wear of a Polymer Thin Film Using the Atomic Force Microscope.


pdf icon Direct Measurement of Plowing Friction and Wear of a Polymer Thin Film Using the Atomic Force Microscope. (271 K)
Du, B.; VanLandingham, M. R.; Zhang, Q.; He, T.

Journal of Materials Research, Vol. 16, No. 5, 1487-1492, 2001.

Keywords:

atomic force microscopy; microscopy; diamond-tipped probe; nanoscale mechanics

Abstract:

Nanometer-scale plowing friction and wear of a polycarbonate thin film were directly measured using an atomic force microscope (AFM) with nanoscratching capabilities. During the nanoscratch tests, lateral forces caused discrepancies between the maximum forces for the initial loading prior to the scratch and the unloading after the scratch. In the case of a nanoscratch test performed parallel to the cantilever probe, the plowing friction will add another component to the moment acting at the cantilevered end compared to the case of nanoindentation, resulting in an increased deflection of cantilever. Using free-body diagrams for the cases of nanoindentation and nanoscratch testing, the AFM force curves were analyzed to determine the plowing friction during nanoscratch testing. From the results of this analysis, the plowing friction was found to be proportional to the applied contact force, and the coefficient of plowing friction was measured to be 0.56 + 0.02. Also, by combining nanoscratch and nanoindentation testing, the energetic wear rate of the polycarbonate thin film was measured to be 0.94 + 0.05 mm3/(Nm).