Multiscale modeling of charge-induced deformation of nanoporous gold structures

Recent experimental studies have shown that nanoporous metals undergo dimensional changes when a potential difference is applied in an electrochemical environment. The primary actuation mechanism is the electric-double layer charging of the internal surface in combination with a large surface-to-volume-ratio. To account for the excess charge we have developed an atomistic model that is calibrated to density functional theory. To make a scale transition from the atomistic to the continuum scale, we propose a surface layer model that is informed by atomistic simulations. We use this multiscale approach to study the charge-induced actuation response of ordered (cubic lattices and gyroids) and disordered nanoporous gold (npg) architectures. Results are presented in terms of the charge-induced actuation strain and work density as a function of relative density, ligament size and architectural morphology. The differences between ordered and disordered structures are critically addressed.