EXC 3120 BlueMat - Research Topic A1: Hydrogen-Driven Nanoporous Materials

We will develop a hydrogen-enabled acoustic metamaterial. The key parameter is the wavelength of sound, which needs to be (1) small (in the order of mm to cm) to enable miniaturization and (2) tunable to enable device switching. The wavelength is determined by the ratio of elastic modulus to mass density. As these parameters are usually strongly correlated, mate- rials with the required properties do not currently exist. A promising approach, demonstrated in preliminary research by the members of the RA A team, is np-Pd, which substantially changes its elastic compliance when alloyed with hydrogen. Thus, a metal/water hybrid nanomaterial achieves switching when hydrogen is relocated between its metal and water phases under the control of an electric potential bias. This new effect implies that one and the same metallic body can be reversibly switched between a hard-matter-like elastic response characteristic of metals and a supercompliant characteristic of soft matter, such as polymers or biological tissue. The key scientific questions are: How can the underlying materials design be shaped in terms of base metal composition and microstructure? How can the open-system elastic response in a nanoscale material with complex microstructural geometry be understood? How can processing routes for components that meet the requirements of Topic A4 be established?