MSE 298 Seminar (Zoom): Programming Intelligence through Geometry, Topology and Anisotropy

Zoom: Meeting ID 842 506 6501, Passcode 587901

Abstract: Programmable shape-shifting materials can take different physical forms to achieve multifunctionality in a dynamic and controllable manner. Geometry is concerned with the configurations of points, lines and circles, while topology is concerned with space, dimension and transformation. By introducing holes and cuts in 2D sheets macroscopically, we demonstrate dramatic shape change and super-conformability via expanding or collapsing of the hole arrays without deforming individual lattice units. When choosing the cuts and geometry correctly, we show folding into the third dimension, known as kirigami. The kirigami structures can be rendered pluripotent, that is changing into different 3D structures from the same 2D sheet. We explore their potential applications in energy efficient building facade, super-stretchable and shape-conformable energy storage devices and medical devices, as well as bioinspired robotics. We then take geometry in both nano- and microscales by programming anisotropy in liquid crystal elastomers (LCEs) to direct folding of the 2D sheets into 3D shapes, which can be triggered by heat, light and electric field. Taking this knowledge of guided inhomogeneous local deformations in LCEs, we tackle the inverse problem – pre-programming geometry on a flat sheet to take an arbitrary desired 3D shape, as well as reprogramming of LCE sheets.

Bio: Shu Yang is a professor in the Departments of Materials Science and Engineering, and Chemical and Biomolecular Engineering at University of Pennsylvania. Her group is interested in synthesis, fabrication and assembly of soft materials including polymers, liquid crystals and colloids and their hybrids with precisely controlled size, shape and geometry; investigation of the dynamic tuning of their sizes and structures, and use of geometry to create highly flexible, stretchable, super-conformable and foldable devices. Her lab explores potential applications of including self-cleaning coatings, dry adhesives, smart windows, sensors, actuators for robotics and biomedical devices. Yang received her bachelor's degree from Fudan University, China in 1992, and a doctorate in chemistry and chemical biology while researching in the Department of Materials Science and Engineering at Cornell University in 1999. She worked at Bell Laboratories, Lucent Technologies as a member of the technical staff before joining Penn in 2004. She received the George H. Heilmeier Faculty Award for Excellence in Research from Penn Engineering (2015-2016). She is a fellow of the Division of Soft Matter (DSOFT) from the American Physical Society, the Division of Polymeric Materials: Science and Engineering from American Chemical Society (ACS) (2018), the Royal Chemical Society (2017) and the National Academy of Inventors (2014). In 2004, she was selected as one of the world’s top 100 young innovators under age 35 by MIT's Technology Review.