Nanoindentation measurement of mechanical properties of soft solid covered by a thin liquid film

Abstract

The presence of a surface-covering liquid film may significantly affect property measurement by nanoindentation on an underlying solid specimen, by causing an artificial drift of the reference point for tip displacement and exerting a surface-tension traction on the tip. The first effect can be corrected for by identifying the hard contact point between the tip and the solid in the load-displacement curve. The second effect can be corrected for by a formula derived in this work, which can also correct for the intrinsic viscoelasticity effects of the solid sample. The correction procedure proposed is validated by experimentation on wet polypropylene.