Bio-inspired pneumatic shape-morphing elastomers

Abstract

Shape-morphing structures are at the core of future applications in aeronautics¹, minimally invasive surgery², tissue engineering³ and smart materials⁴. However, current engineering technologies, based on inhomogeneous actuation across the thickness of slender structures, are intrinsically limited to one-directional bending⁵. Here, we describe a strategy where mesostructured elastomer plates undergo fast, controllable and complex shape transformations under applied pressure. Similar to pioneering techniques based on soft hydrogel swelling^6-10, these pneumatic shape-morphing elastomers, termed here as 'baromorphs', are inspired by the morphogenesis of biological structures^11-15. Geometric restrictions are overcome by controlling precisely the local growth rate and direction through a specific network of airways embedded inside the rubber plate. We show how arbitrary three-dimensional shapes can be programmed using an analytic theoretical model, propose a direct geometric solution to the inverse problem, and illustrate the versatility of the technique with a collection of configurations.