Impact of capillarity on mechanical behavior of solids in contact with a fluid

Abstract

This contribution summarizes results of in situ experiments with nanoporous metals prepared by dealloying and impregnated with fluid electrolyte that reveal a strong impact of capillary forces—surface tension and surface stress—on the mechanical behavior of nanomaterials. The relevant phenomena include actuation, quasi-piezoelectric response, switchable elastic modulus, strength, and plastic Poisson's ratio. A reversible switching of these properties is realized via electric potentials imposed to the large metal-electrolyte interface of the materials, and consequent control of the surface state through electrical polarization and adsorption. Analysis of the mechanics of the electrified high-surface area solids and its link to the electrocapillary response of surface electrodes allowed to identify a governing capillary parameter for the specific mechanical property.