The surface stress of a metallic solid-body immersed in an electrolyte can be modified by variation of an applied electrical potential. The stress at the surface is transferred to the underlying bulk material, where it leads to strain and, hence, electrochemical actuation. For massive bodies, which exhibit a small ratio of surface to volume atoms, this effect is sparsely pronounced and not usable. Nanoporous metals on the other hand exhibit a high intrinsic, externally accessible surface area and are therefore suitable as functional materials such as sensors or actuators. Another class of chemo-mechanical actuators are electrically conductive polymers, which swell or shrink through the potential-controlled incorporation or removal of anions. Fast ion exchange is possible with thin layers, yet the stiffness of supporting substrates limits their effect for actuation. The combination of both approaches via coating of the inner surface of nanoporous gold with polypyrrole results in a hybrid material with significantly improved electrochemical and actuatoric properties.

This contribution focuses on the manufacturing of hybrid materials consisting of nanoporous gold and electrically conductive polymers, its chemo-mechanical properties as well as the underlying electro-chemo-mechanical coupling mechanisms.