A method for testing the viscoelastic property of polymer micro-pillars, based on
open-loop flat punch indentation, is presented. The difficulties in performing a
conventional creep or stress relaxation test using a nanoindentation apparatus
with a leaf-spring structure are described and the advantages of our method
explained. An analytic model for the test was devised and a simple formula for
measuring creep compliance provided. As an example, polymer micro-pillars were
fabricated on a glass substrate using nano-stereolithography (NSL) and their
creep compliance measured. Experimental details are presented, including testing
procedure, processing of raw data and analysis of test results, plus some issues,
related to measurement uncertainty, are discussed, such as sensor resolution,
parallelism, thermal drift and damping force.