Description:

Foldable and Responsive Soft Metamaterials

By: Shu Yang

Abstract: Materials that can expand and collapse, fold, and transform into a variety shapes have attracted significant interest and have obvious applications in flexible electronics, color displays, smart windows, actuators, sensors, and both photonic and phononic devices. But how can we render a rigid device super-flexible so that it can wrap around a sphere without bending and stretching? How can flat surfaces be transformed into any desired 3D structure without disruptive stretching and deformation?
In my talk, I will show several examples how we introduce holes and cuts in periodically structured materials, so called metamaterials, exhibiting dramatic shape change (e.g. ~800% areal expansion) and super-conformability via expanding or collapsing of the periodic 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 then pre-program the buckling direction and curvatures by introducing notches on existing kirigami structures or by embedding cues in surface patterns of liquid crystal elastomers with internal strains. Lastly, I will show our initial success in additive manufacturing toward textile based self-folding devices.

Bio: Shu Yang is a Professor in the Departments of Materials Science & Engineering, and Chemical & Biomolecular Engineering at University of Pennsylvania, and Director of Center for Analyzing Evolved Structures as Optimized Products (AESOP): Science and Engineering for the Human Habitat. Her group is interested in synthesis, fabrication and assembly of polymers, liquid crystals, and colloids with precisely controlled size, shape, and geometry; investigating the dynamic tuning of their sizes and structures, and the resulting unique optical, mechanical and surface/interface properties. Yang received her B.S. degree from Fudan University, China in 1992, and Ph. D. degree from 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 Technical Staff before joining Penn in 2004. She received George H. Heilmeier Faculty Award for Excellence in Research from Penn Engineering (2015-2016). She is elected as Fellow of National Academy of Inventors (2014) and TR100 as one of the world’s top 100 young innovators under age of 35 by MIT's Technology Review (2004). She was a recipient of ICI (1999) and Unilever (2001) student awards from American Chemical Society (ACS) for outstanding research in polymer science and engineering.