Top: A printed electrode pattern of the new polymer being stretched to several times of its original length. Bottom: A transparent, highly stretchy “electronic skin” patch forming an intimate interface with the human skin to potentially measure various biomarkers. Photograph courtesy of the Bao Lab and Stanford University.
Zhenan Bao, PhD, a professor of chemical engineering and material science and engineering at Stanford University, is one of five women from around the world who was awarded the 2017 L’Oréal-UNESCO For Women in Science Awards in the physical sciences. Bao was recognized for “inventing skin-inspired electronic material,” which would improve the quality of life of people who use prostheses. She and her team have spent over a decade creating soft and flexible electronics that feel and operate almost like a second skin, including artificial skin that is touch-sensitive and self-healing, and artificial skin that detects pressure.
On March 10, Bao and a team of colleagues published a paper in Science Advances that describes their latest work, which involves using a soup-thickening additive to create a stretchable, plastic electrode that stretches like rubber but carries electricity like wires, paving the way for flexible electronics. The team took brittle plastic and modified it chemically to make it as bendable as a rubber band, while slightly enhancing its electrical conductivity. The result is a soft, flexible electrode that is compatible with supple and sensitive nerves.
“This flexible electrode opens up many new, exciting possibilities down the road for brain interfaces and other implantable electronics,” said Bao. “Here, we have a new material with uncompromised electrical performance and high stretchability.”
The plastic in this experiment was made of two polymers that were tightly wound together. One was the electrical conductor and the other was essential to the process of making the plastic. When the polymers were combined, they created a plastic with a string of brittle, sphere-like structures. It was conductive, but not flexible. By adding a molecule similar to the additives used to thicken soups in industrial kitchens, it transformed the plastic’s chunky and brittle molecular structure into a fishnet pattern with holes in the strands to allow the material to stretch and deform. Testing showed that the new material’s elasticity became slightly more conductive when stretched to twice its original length and the plastic remained very conductive even when stretched 800 percent its original length.
Bao’s stretchable plastic is designed to make a more seamless connection between the world of stiff electronics and the flexible organic electrodes in our bodies. The material is still a laboratory prototype, but the team hopes to develop it as part of their long-term focus on creating flexible materials that interface with the human body.
The L’Oréal-UNESCO For Women in Science Awards are presented every year to five women, one from each world region (Africa and the Arab States, Asia-Pacific, Europe, Latin America, and North America) in recognition of their scientific accomplishments. Each scientist has had a unique career path combining exceptional talent, a deep commitment to her profession, and remarkable courage in a field still largely dominated by men. The winners were proposed by an international community of more than 2,000 leading scientists, and were selected by an independent international jury. Each award winner received a prize of ?100,000 to reward their contribution to science.
Editor’s note: This story was adapted from materials provided by Stanford University.