Viscoelastic characterization of polymers using instrumented indentation. II. Dynamic testing

Abstract

Dynamic nanoindentation was performed on a cured epoxy, a poly(methyl methacrylate) (PMMA), and two poly(dimethyl siloxane) (PDMS) samples of different crosslink densities. These samples were used to compare dynamic nanoindentation with classical rheological measurements on polymeric samples in the glassy and rubbery plateau regions. Excellent agreement between bulk rheological data and dynamic nanoindentation data was observed for the two glassy materials (epoxy and PMMA) and the less compliant PDMS sample. More divergent results were observed for the more compliant PDMS sample. The theoretical foundation and historical development of the working equations for these two types of instrumentation are presented and discussed. The major difference between nanoindentation and the more classical rheological results is in the treatment of the instrument-sample interface. © 2005 Wiley Periodicals, Inc.