Indentation experiments at the nanometer and micrometer range reported in the
literature have shown that the deformation of polymers is —similarly to metals
—size-dependent. In addition its size dependence, the deformation behavior of
polymers is also known to be rate-dependent. Here silicone rubber is considered. In
order to characterize the relation between size and rate-dependent deformation
indentation tests of silicone at indentation depths of between 30 and 300 microns and
loading times of between 1 and 1000 seconds are performed. In these experiments
the hardness and dissipation increased with decreasing loading time and
decreasing indentation depth. These experimental results are analyzed with a
recently suggested indentation model which incorporates a Frank energy-related
nonlocal deformation work. It is found that the indentation model is in good
agreement with the experimental data. Evaluation of the experimental data
indicates that the rate effects are mostly related to the nonlocal, size-dependent
deformation.