Miniaturised mechanical testing

Usually, samples of macroscopic size are used to study the mechanical behavior of polymers in the solid state, e.g. elasticity, yielding, and strain hardening. While this is a viable route for commodity polymers, the availability of material becomes increasingly limited the more special the polymers under consideration. Particularly, at the forefront of research, where chemists developed small amounts of specialty polymers, the classical approach to mechanical testing fails. To that end, we develop a novel technique for mechanical testing of small column-shape pillars with diameters ranging from 20 µm to 60 µm, and aspect ratios from 1 to 1.5. In order to prepare the column-shape samples, focused ion beams are used. The so-produced sample are then tested under compression with a diamond flat punch of 100 µm in diameter, using the Nanoidenter XP (MTS Instruments), that permits force and displacement measurements with resolutions of 1 µN and 30 nm, respectively. The goal of this study is twofold. On the one hand, we strive to perform small-sample tests that are representative of the behavior of macroscopic samples. On the other hand, we also consider aspects in mechanical behavior that is characteristic for small scales, but absent on macroscopic scales.

Research type: Experimental