Berlin 2018 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 39: Topical session (Symposium EPS and MM): Mechanical Properties at Small Scales
MM 39.5: Vortrag
Mittwoch, 14. März 2018, 16:15–16:30, H 0107
Effect of Polypyrrole Coating on the Elasticity of Nanoporous Gold — •Jie Li1, Nadiia Mameka1, Jürgen Markmann1,2, and Jörg Weissmüller1,2 — 1Institute of Materials Research, Materials Mechanics, Helmholtz-Zentrum Geesthacht, Geesthacht, Germany — 2Institute of Materials Physics and Technology, Hamburg University of Technology, Hamburg, Germany
Dealloying-derived millimeter-size nanoporous gold (np-Au), consisting of interconnected single nanoligaments network with large surface area, exhibits a switchable elastic modulus when its surface is electrically polarized in aqueous electrolyte [1]. Here, we decorate the surface of np-Au by a conductive polymer polypyrrole (PPy) that is also known to exhibit tunable Young's modulus upon charging in electrolytes [2]. While keeping the original porous structure, we have achieved a uniform PPy coating of various thicknesses in bulk np-Au by electropolymerization. The np-Au/PPy composites are then infiltrated by an aqueous electrolyte and subjected to potential variation in dynamic mechanical analyzer (DMA). The in situ DMA experiments reveal that the stiffness variation reaches the same magnitude as in the oxidation/reduction regime on pure gold without polymer coating. The material softens upon negative charging. We discuss possible mechanisms for the stiffness variation. [1] Mameka et al , Acta Mater. 76 (2014) 272. [2] Shoa et al, Synthetic Mater. 160 (2010) 1280.