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 39.6: Vortrag
Mittwoch, 14. März 2018, 16:30–16:45, H 0107
Self-assembled monolayers of alkanethiols strengthen nanoporous metal — •Nadiia Mameka1, Hartmut Gliemann2, Jörg Weissmüller1,3, and Christof Wöll2 — 1Helmholtz-Zentrum Geesthacht, Geesthacht, Germany — 2Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany — 3Hamburg University of Technology, Hamburg, Germany
As one of the consequences of the large specific surface area of nanoporous metals, their mechanical behavior is sensitive to the surface chemistry. Studies on nanoporous gold (NPG) modified by a molecular monolayer of OH− ions exemplify this, finding two-fold increase of strength [1] and 8% increase of stiffness [2].
Here, we employ self-assembled monolayers (SAMs) of alkanethiols to modify NPG surface. Alkanethiol molecules, consisting of a sulfur headgroup that strongly interact with a metal substrate, a hydrocarbon chain and end-group, are known to spontaneously self-organize into well-ordered, dense two-dimensional molecular films. Alkanethiols with various chain lengths and terminal groups were used to prepare SAMs on bulk NPG and compression tests were performed on the SAM-modified and non-modified macroscopic samples. Our experiments reveal the substantial strengthening of the material due to the thiol adsorption that can reach up to 40%. This talk will discuss possible strengthening mechanisms mediated by the metal-sulfur interaction.
[1] Jin, Weissmüller, Science, 332 (2011) 1179. [2] Mameka et al, Acta Materialia, 76 (2014) 272.