Charge-induced actuation of nanofoams

Nanofoams are large atomic structures with interconnected networks and different porosities. The nanometer-sized subunits combined with the tunable architectural morphology allow this new class of materials to find application in actuators, catalysts and supercapacitors. The use of nanofoams as electrochemical actuator is especially interesting since strain amplitudes can be generated that are comparable to those of piezoelectric ceramics, but at much lower voltages (1V compared to 100 V). In this work we aim at studying the actuation and mechanical properties of metal nanofoams[1] and graphene honeycomb networks[2]. With the aid of in-house developed theoretical and atomistic models we have studied the actuation and mechanical properties of gold nanowires, gold nanofoams and graphene nanoribbons. Next, we will study graphene honeycomb networks with struts made of stacked graphene layers. To capture the actuation mechanism, we use molecular dynamics to study the charge-induced response of graphene structures. The intermolecular reactive bond order potential (AIREBO) is modified to account for the excess charge.So far, the actuation properties of individual graphene ribbons have been studied. In the next phase, we plan to study the effect of relative density and size of individual struts on the actuation and mechanical properties of honeycomb networks. However, in case of honeycombs the large number of atoms coupled with the large interaction distance of the Van der Waals interactions (approx. 10 Å) demands a considerable amount of computational resources.