Switchable imbibition in nanoporous gold

Spontaneous imbibition enables the elegant propelling of nano-flows because of the dominance of capillarity at small length scales. The imbibition kinetics are, however, solely determined by the static host geometry, the capillarity, and the fluidity of the imbibed liquid. This makes active control particularly challenging. Here we show for aqueous electrolyte imbibition in nanoporous gold that the fluid flow can be reversibly switched on and off through electric potential control of the solid-liquid interfacial tension, that is, we can accelerate the imbibition front, stop it, and have it proceed at will. Simultaneous measurements of the mass flux and the electrical current allow us to document simple scaling laws for the imbibition kinetics, and to explore the charge transport in the metallic nanopores. Our findings demonstrate that the high electric conductivity along with the pathways for fluid/ionic transport render nanoporous gold a versatile, accurately controllable electrocapillary pump and flow sensor for minute amounts of liquids with exceptionally low operating voltages.

Subjects

fluid dynamics

materials Science

soft condensed matter

chemical physics

DDC Class

530: Physik

Funding(s)

SFB 986: Teilprojekt B2 - Feste und leichte Hybridwerkstoffe auf Basis nanoporöser Metalle

Publication version

publishedVersion

Lizenz

https://creativecommons.org/licenses/by-nc-sa/4.0/

Name

ncomms5237.pdf

Size

1023.81 KB

Format

Adobe PDF

Options

Switchable imbibition in nanoporous gold