Programmable shape-shifting materials can take different physical forms to achieve multifunctionality in a dynamic and controllable manner. By introducing holes and cuts in 2D sheets, we demonstrate dramatic shape change and super-conformability via collapsing or expanding of the hole arrays in the micro- and macroscales. When choosing the cuts and geometry correctly, we show folding into the third dimension, known as kirigami. By programming the geometry of cuts and folding angles, here, I discuss two potential applications.
By programming kirigami metamaterials with controllable local tilting orientations on demand through prescribed notches, we show their potential application as energy-saving building envelopes that can be open and close on demand. By controlling the folding angle, we show centimetric kirigami structures can form quasi-stable counter-rotating vortices that regulate the trajectories of incoming fog clusters and eject extensive droplets to the substrate. Together with gravity-directed gathering by the folds, the kirigami fog collector yields a collection efficiency of 16.1% at a low wind speed of 0.8 m/s and is robust against surface characteristics.
Shu Yang is Joseph Bordogna Professor of Engineering and Applied Science
and Chair of the Department of Materials Science & Engineering, and Professor of Chemical & Biomolecular Engineering at University of Pennsylvania. Her group is interested in synthesis, fabrication, and assembly of soft materials and composites, and use of geometry to create smart and bioinspired materials that are highly stretchable, super-conformable, and shape transformable for potential applications, including coatings, adhesives, structural colors, sensors, actuators for soft robotics, biomedical devices, and energy efficient building components. Yang received her B.S. degree from Fudan University and Ph. D. degree from Cornell University. She worked at Bell Laboratories, Lucent Technologies as a Member of Technical Staff before joining Penn. She received George H. Heilmeier Faculty Award for Excellence in Research from Penn Engineering. She is a Fellow of Materials Research Society (MRS), American Chemical Society (ACS), Division of Soft Matter (DSOFT) from American Physical Society (APS), Division of Polymeric Materials: Science and Engineering from ACS, and National Academy of Inventors. She was elected as Innovators under 35 by MIT's Technology Review.