Think big: overcoming gravity in large scale shape morphing structures.*

Nature is ripe with shape morphing structures – plant leaves, organs – whose transformations are driven by differential growth. In the laboratory, these mechanisms have inspired numerous shape-shifting structures, typically relying on a change of the metrics following the application of a stimulus, e.g. temperature, UV-light, electric field, or pressure, in some carefully crafted soft materials; or else strategies to change the apparent metric, e.g. origami folds and kirigami cuts.  While the later heavily rely on craftsmanship for fabrication – think of the difficulty to fold an origami – and are thereby limited in scale, the former are usually restricted to small settings (tenth of centimeters or less), where gravity is negligible or is made negligible (neutrally buoyant conditions). These limitations are an impediment to the translation of these approaches to larger length scales, where necessary stiffness competes with the ability to deform largely. Here we present preliminary results obtained in identifying strategies to overcome the aforementioned challenges. Particular attention is given to combining existing techniques, e.g. origami-like structures and pneumatic actuations, and exploring new avenues of research, e.g. the jamming of granular media enclosed in elastic structures.