Berlin 2018 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 38: Nanomaterials

MM 38.4: Talk

Wednesday, March 14, 2018, 16:00–16:15, H 0106

Hybrid Materials Made From Nanoporous Metals and Electrically Conductive Polymers for Electrochemical Actuation — •Benedikt Roschning¹ and Jörg Weissmüller^{1, 2} — ¹Institute of Materials Physics and Technology, Hamburg University of Technology, Hamburg, Germany — ²Institute of Materials Research, Materials Mechanics, Helmholtz-Zentrum Geesthacht, Geesthacht, Germany

The variation of an applied electrical potential modifies the surface stress of solid metals immersed in electrolyte. This variation of surface stress is transferred to the underlying bulk material, where it causes compensating stresses. The associated strain strain may be exploited for electrochemical actuation. The effect is small in conventional macroscopic bodies, due to their small surface to volume ratio. By contrast, nanoporous metals have a high internal surface area; these materials may be suitable as functional materials like sensors or actuators. Electrically conductive polymers, such as polypyrrole, swell or shrink through the potential-controlled incorporation or removal of anions. They constitute another class of chemo-mechanical actuators. Fast ion exchange is possible within thin polymer layers on planar conductive substrates, but the stiffness of the substrate limits the actuation amplitude. Combining the two mentioned approaches we investigate the actuation with nanoporous gold functionalized by coating the internal surface with polypyrrole. We show that these hybrid materials exhibit significantly enhanced actuation. The presentation also addresses the underlying coupling mechanisms.