Device: Sharkskin and raisins helped inspire researchers at Massachusetts Institute of Technology to create miniscule, precisely patterned wrinkles, with possible applications ranging from medical devices to light-enhancing technology in photovoltaics.
The project started as a way to design “anti-fouling” materials—surfaces that would inhibit the formation of bacterial biofilms, known as “biofouling.” It’s well known that surfaces with “topology”—such as the tooth-like projections on sharkskin—can prevent biofouling, explained Mary Boyce, head of the mechanical engineering department at MIT, who led the research. But rather than simply etch patterns into a surface, Boyce and her colleagues wanted a material that automatically carried this anti-fouling characteristic.
Enter the raisin. Raisins are wrinkled because the outer skin cannot shrink enough to accommodate its newly down-sized center, which contracts as a result of evaporative water loss. Boyce and her postdoc Jie Yin used two layers of differing elastic properties to get a similar effect.
First, ...
