Semiordered hierarchical metallic network for fast and large charge-induced strain

Nanoporous metallic actuators for artificial muscle applications are distinguished by combining the low operating voltage, which is otherwise reserved for polymer-based actuators with interesting values of strain amplitude, strength, and stiffness that are comparable of those of piezoceramics. We report a nanoporous metal actuator with enhanced strain amplitude and accelerated switching. Our 3D macroscopic metallic muscle has semiordered and hierarchical nanoporous structure, in which μm-sized tubes align perpendicular with the sample surface, while nm-sized ligaments consist of the tube walls. This nanoarchitecture combines channels for fast ion transportation with large surface area for charge storage and strain generation. The result is a record reversible strain amplitude of 1.59% with a strain rate of 8.83 × 10-6 s-1 in the field of metallic based actuators. A passive hydroxide layer is self-grown on the metal surface, which not only contributes a supercapacitive layer, but also stabilizes the nanoporous structure against coarsening, which guarantees sustainable actuation beyond ten-thousand cycles.

Subjects

Artificial muscle

charge-induced strain

electrochemical actuation

hierarchical nanoporous structure

nanoporous metal

DDC Class

530: Physik

600: Technik

Funding(s)

SFB 986: Zentralprojekt Z3 - Elektronenmikroskopie an multiskaligen Materialsystemen

More Funding Information

the financial support by DFG via SFB “M3”, subproject B2.

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Semiordered hierarchical metallic network for fast and large charge-induced strain