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MM: Fachverband Metall- und Materialphysik
MM 1: Topical Session Nanoporous Functional Materials I
MM 1.4: Talk
Monday, March 23, 2009, 11:30–11:45, IFW A
A light-weight, large strain nanoporous actuator material that can be used in compression — •Lihua Shao1, Jürgen Biener2, Dominik Kramer1, Viswanath Raghavan Nadar1, Theodore F. Baumann2, and Jörg Weissmüller1 — 1Forschungszentrum Karlsruhe, Institut für Nanotechnologie, Karlsruhe, Germany — 2Lawrence Livermore National Laboratory, Livermore, California, USA
Considerable progress has been made about the charge induced strain of nanoporous materials. Possible actuator applications have been suggested for noble metals and carbon nanotubes. The high costs of such materials are an impediment to application, as the fact that carbon nanotube arrays cannot be loaded in compression. It is therefore of interest to search for alternative materials which combine mechanical and chemical stability with low cost. We will report first results on the mechanical and electrochemical properties of a light-weight, bulk material with extremely large surface area that can be used in compression, and that achieves a reversible strain of 0.45%. Besides actuation applications, nanoporous solids impregnated by electrolyte are also of interest with regards to the measurement of a fundamental parameter, namely the potential of zero charge (pzc). For liquid metals the pzc coincides with the maximum of the surface tension, from which it can be measured. However, the strain of solids is governed by the surface stress, which is not a maximum at the pzc. We measured the pzc and the charge-dependent strain in various electrolytes and excluded an agreement between pzc and the potential of length minimum.