•Dominik Kramer¹, Raghavan Nadar Viswanath¹, Jörg Weissmüller^1,2 und Herbert Gleiter^1
1Forschungszentrum Karlsruhe, Institut für Nanotechnologie, Karlsruhe, Germany
²Universität des Saarlandes, Fachrichtung Technische Physik, Saarbrücken, Germany

It has been suggested that it should be possible to tune electron-density dependent structural and physical properties of systems with a high surface-to-volume-ratio, especially nanocrystalline materials, by changing the charge density at the surface [1]. One example of such a property is the lattice constant and the dimension of nanocrystalline porous metal samples. Here we show that the strain in a metal can be reversibly changed by charging the nanoporous sample in an electrolyte impregnating the pores. We present in-situ dilatometer and X-ray measurements of nanoporous gold that was prepared by dealloying a gold-silver alloy in perchloric acid. Reversible changes of the length of the samples were observed in various electrolytes, dependent on the potential vs. a reference electrode. It is suggested to exploit this effect to construct nanoporous metallic actuators. They need larger currents than piezoelectric materials, but have the advantage to work with small voltages.