Interface elasticity effects in polymer-filled nanoporous metals

A continuum formulation for electroactive composites made from nanoporous gold and ion conducting polymer is proposed. A novel extension of surface elasticity theory is developed to account for the high surface-to-volume ratio of nanoporous gold, and to capture the chemoelectromechanical coupling that occurs on the interface between the metal and the polymer. This continuum formulation accounts for the fully non-linear behaviour exhibited by the composite. The balance of linear momentum, Galas flux theorem and a relation for the transport of charge carriers are introduced in the bulk material as well as on the interface to describe the non-linear multiphysics and highly coupled response of the actuator. The resulting system of nonlinear equations is solved using the finite element method. A series of numerical examples is presented to elucidate the theory.