Ambient Pressure-Driven Actuators and Shape-Morphing Metamaterials
Actuators which change shape in response to ambient pressure have great potential for use in extreme environments, from space to the deep ocean. Bi-layer actuators have so far not been explored to this end, despite their lightness and mechanical simplicity (there is no requirement for a separate power source or pump, for example) making them ideal for applications where transport and maintenance are difficult. In this paper, foam-based bilayer actuators powered by ambient pressure change have been constructed, modelled mathematically, characterised in terms of their actuating force, and built into deployable devices and metamaterial structures to showcase properties such as negative pressure expansivity. Actuators such as these are ideally suited for a range of applications, from deploying solar panels and sensors in space and extra-terrestrial atmospheres, to under-sea expandable structures and sensing.