The Yang lab and collaborators transform a two-dimension sheets made from liquid crystal elastomers into complex three-dimensional geometries, such as a human face, with heat. This work outlines an explicit protocol for preprogramming any desired 3D shape into a 2D liquid crystal elastomer (LCE) sheet. Namely, given an arbitrary 3D design, we show how to … Read more

Wearable sensors allow for continuous and real-time monitoring of the human health and potential environmental hazards such as ultraviolet (UV) radiation on the daily basis. Here, textile-based wearable UV indicators are fabricated, which can show easily recognizable color patterns depending on UV irradiation intensity over time. The sensors are prepared by templating electrospun polycaprolactone fibers … Read more

Stimulus-responsive soft materials that can enable folding of a 2D sheet into a 3D object have potential significant applications, including wearable electronics, biomimetic machines, soft robotics, drug delivery, biomedical devices, and responsive buildings. The responses can be tuned by the materials chemistry, composition, and type of external stimulus; the direction and magnitude of the deformation … Read more

Commonplace as they are, windows are an important piece of technology. Beyond architectural aesthetics, a building’s ecological footprint depends heavily on how its internal light and heat are managed. With this in mind, the Yang lab develop smart windows by infusing a clear silicone sheet with silica nanoparticles. The composite film is transparent in the … Read more

We often meet with this dilemma: material’s adhesion could be strong but not reversible, or it is reversible but not strong. The Yang lab discovered that hydrogel made from polyhydroxyethylmethacrylate (PHEMA) had unusual adhesive properties akin to that of the snail’s epiphragm: PHEMA was rubbery when wet but rigid when dry.  When wet, PHEMA conforms … Read more

Liquid crystal elastomers (LCEs), known for their reversible and anisotropic deformation, are promising candidates as embedded intelligent actuators in soft robots. Using an extrusion process, meter-long LCE composite filaments that are responsive to both infrared light and electrical fields are fabricated. When a small quantity of cellulose nanocrystals (CNCs) is incorporated to facilitate the alignment … Read more

Liquid crystals are composed of rod- or disc-like molecules called mesogens, and, as a result of the alignment of these mesogens, exhibit remarkable physical properties in between those of a solid and a liquid. The liquid crystals used in this study are made of oligomers, flexible short-chain polymers comprised of smaller rod-like molecular building blocks. … Read more

Inspired by cephalopod’s skin, the Yang lab creates an artificial chromatophore that can change colors instantly—from near-infrared to visible to ultraviolet—on demand, by inflating thin, flexible membranes made from cholesteric liquid crystal elastomers, where the mesogens are arranged in helical shapes. As the membrane is placed on top of a cavity and inflated, the pitch … Read more

Shu Yang of the School of Engineering and Applied Science has developed an artificial chromatophore that can change colors on command by taking inspiration from active camouflage in the animal kingdom. Made from polymer networks of liquid crystals arranged in helical shapes, these membranes require less deformation to change color than previous models, which could lead … Read more

Inspired by biological structural materials, Yang, Liang Feng (Penn Engineering, MSE) and Masoud Akbarzadeh (PennDesign, Architecture) have received $4.6M grant from National Science Foundation (NSF) in collaboration with researchers at Princeton University (Andrej Košmrlj and Pierre-Thomas Brun), Rowan University (Xiao Hu) and Rutgers University Camden (David Salas-de la Cruz) to drive eco-future manufacturing of highly efficient structures and components that are … Read more