Direct Measurement of Plowing Friction and Wear of a Polymer Thin Film Using the Atomic Force Microscope.
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).
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899