title: Surface-chemistry-driven actuation in nanoporous gold.
abstract: Although actuation in biological systems is exclusively powered by chemical energy, this concept has not been realized in man-made actuator technologies, as these rely on generating heat or electricity first. Here, we demonstrate that surface-chemistry-driven actuation can be realized in high-surface-area materials such as nanoporous gold. For example, we achieve reversible strain amplitudes of the order of a few tenths of a per cent by alternating exposure of nanoporous Au to ozone and carbon monoxide. The effect can be explained by adsorbate-induced changes of the surface stress, and can be used to convert chemical energy directly into a mechanical response, thus opening the door to surface-chemistry-driven actuator and sensor technologies.
authors.affiliation: Nanoscale Synthesis and Characterization Laboratory, Lawrence Livermore National Laboratory, Livermore, California 94550, USA. biener2@llnl.gov
authors.forename: J
authors.initials: J
authors.lastname: Biener
authors.forename: A
authors.initials: A
authors.lastname: Wittstock
authors.forename: L A
authors.initials: LA
authors.lastname: Zepeda-Ruiz
authors.forename: M M
authors.initials: MM
authors.lastname: Biener
authors.forename: V
authors.initials: V
authors.lastname: Zielasek
authors.forename: D
authors.initials: D
authors.lastname: Kramer
authors.forename: R N
authors.initials: RN
authors.lastname: Viswanath
authors.forename: J
authors.initials: J
authors.lastname: Weissmüller
authors.forename: M
authors.initials: M
authors.lastname: Bäumer
authors.forename: A V
authors.initials: AV
authors.lastname: Hamza