“We’ve designed a 3-D, thin-walled structure that can be used to make foldable and reprogrammable objects of arbitrary architecture, whose shape, volume, and stiffness can be dramatically altered and continuously tuned and controlled,” said Johannes TB Overvelde, a graduate student in Bertoldi’s lab and first author of the paper. In a way similar to origami, the cube can be easily folded along its edges for shape alteration. The researchers fixed pneumatic actuators in the structure, which can be set to deform particular hinges, altering the shape and size of the cube, and won’t need external input. The researchers linked up 64 of such individual cells for creating a 4x4x4 cube that can grow, shrink, alter its shape globally, transform the orientation of its microstructure, and fold entirely flat. When the structure changes its shape, its stiffness also gets changed, which means one may come up with a material that is quite flexible or very stiff, with the help of the same design. The actuated alterations in material properties make the material four dimensional. You can fix this material with any type of actuator, like thermal, dielectric or even water. The material can be embedded with any kind of actuator (a system which can move or control it), including thermal, dielectric, or even water. “We do not only understand how the material deforms, but also have an actuation approach that harnesses this understanding,” said Bertoldi. “We know exactly what we need to actuate in order to get the shape we want.” “The opportunities to move all of the control systems onboard combined with new actuation systems already being developed for similar origami-like structures really opens up the design space for these easily deployable transformable structures,” said Weaver. “This structural system has fascinating implications for dynamic architecture, including portable shelters, adaptive building facades, and retractable roofs,” said Hoberman. “Whereas current approaches to these applications rely on standard mechanics, this technology offers unique advantages such as how it integrates surface and structure, its inherent simplicity of manufacture, and its ability to fold flat.” “This research demonstrates a new class of foldable material that is also completely scalable,” Overvelde said, “It works from the nanoscale to the metre-scale and could be used to make anything from surgical stents to portable pop-up domes for disaster relief.” This paper was coauthored by Twan A. de Jong, Yanina Shevchenko, Sergio A. Becerra, and George Whitesides. The research was supported by the Materials Research Science and Engineering Centers, the National Science Foundation and the Wyss institute through the Seed Grant Program. The research has been published in Nature Communications.
