For Shu Yang, ideas are everywhere. Sometimes nature provokes inspiration. Other times, a problem causes Yang to see a solution that already exists in the natural world. While trying to create a “building envelope” that could reflect sunlight and collect water to passively heat and cool buildings, she looked to tornado vortices for a new structure for perforated window covers. The dry, grooved skin of the African elephant helped her envision a new kind of stucco that would keep temperatures down in regions experiencing life-threatening heat waves. Yang also developed an adhesive that’s strong enough to hold shelving on walls yet porous enough to be removed if the glue is remoistened. Snail secretion gave her a model to perfect the design.
Yang, a materials scientist at the University of Pennsylvania, consults the natural world when looking to solve humanity’s problems. Pharmaceutical companies mine biology to develop drugs and vaccines, Yang once told herself. Could she do the same thing with engineering? She employs what’s called biomimicry: studying organically occurring structures and rethinking them to inspire new and often more sustainable solutions that meet human needs.
Growing up in China, Yang says her family didn’t have a lot of money. So by necessity she looked outside for entertainment. “There’s not too many things to explore other than nature,” Yang says. Her father was an English professor, and her mother was a physical education teacher. “That’s why I’m also a sprinter,” Yang says of her prolific pace.
While many scientists are wary of speaking about developing theories or unpublished work, Yang isn’t precious. “I have tons of ideas,” she says. Being open during the iterative process also allows her to collaborate with people who have expertise in other fields; she works with biologists, material scientists, and textile engineers.
Once again, the environment provides help: “Penn is really the melting pot,” Yang says. “Because everything is within five to 10 minutes’ walking [distance]—medical school, art and science, design school, and dental school.” She learned to love geometry from Randall Kamien, a colleague in the physics department who showed her that the same geometry can take on different forms across different materials and scales, and how a rigid material can become ultrasoft and expandable simply by introducing cuts. By working with architects, she developed those geometric forms for real-world applications, such as improving building energy efficiency but at a larger scale with low-cost materials. Plastic surgeons’ desire for breast cancer patients’ speedy recovery following a mastectomy led to a medical innovation on a smaller scale: kirigami wrappers to support breast implants. Now Yang is working with a pediatric neurosurgeon to adjust the adhesive she developed as a more gentle and easier to apply alternative to sutures or superglue.
“I don’t think I’m the supersmart person, but I bring the smart people together,” she says. “And any new idea, after a year or two, becomes an old idea.” In the meantime, Yang can focus on her next idea, while her partners take what they’ve worked on together to a place she might never have imagined. One recent collaboration, which originated with the U.S. Department of Energy, is 3D-printed concrete. The technique significantly reduces the environmental impact of producing concrete and cement, which is responsible for about 8 percent of all human-made carbon emissions. Yang’s concrete is made in part from a siliceous skeleton that absorbs carbon dioxide throughout the life of the material. “It’s really a wonderful choice,” Yang says with a smile. An organically occurring structure with a similar strength and porosity: honeycombs.