•VISWANATH RAGHAVAN NADAR¹, JÖRG WEISSMÜLLER^1,2, DOMINIK KRAMER¹, ROLAND WÜRSCHUM³ und HERBERT GLEITER^1
1Institut für Nanotechnologie, Forschungszentrum Karlsruhe, Karlsruhe, Germany
²Universität des Saarlandes, Fachrichtung Technische Physik, Saarbrücken, Germany
³Technische Universität Graz, Institut für Technische Physik, Graz, Austria

We present the results of our recent findings that the lattice constant and the dimension of a metal can be changed reversibly by the strain induced by varying the electric charge density of the surface. The results presented here represent an experimental evidence in support of the suggestion that a wider range of properties of metals may be reversibly tuned by simply adding or withdrawing charges at surfaces or internal interfaces by means of an applied electric potential. A reversible strain amplitude in excess of 0.1% has been obtained by charging inter-connected nm sized three dimensional porous structured nanocrystalline platinum immersed in aqueous and non-aqueous electrolytes at different external applied potentials. The experimental techniques, in-situ dilatometry and in-situ X-ray diffraction, have been used to estimate the crystal strain. The variation of the strain obtained from the platinum metal is remarkable since analogous findings have previously only been observed for ionic and covalently bonded materials such as carbon nanotubes or conducting polymers.