John Rogers’s Bendable Microprocessors
John Rogers was in his lab at the University of Illinois at Urbana-Champaign six years ago, testing new ways to make electronic circuits, when one of his team members made a mistake. The researcher accidentally pulled a piece of rubber taut as he placed it underneath a circuit; when he released the stretched rubber, it sprang back and the circuit became a wavy, buckled mess. Rogers, a materials scientist, took a look at the results under a microscope and saw what he characterizes as “an accordion made of silicon.” He realized he had hit pay dirt. “This is not a problem,” Rogers recalls thinking at the time. “This is an opportunity.”
Working off this discovery, the 2009 MacArthur “genius” award winner has developed a way to make microprocessors so bendable and thin that they look like electronic skin. The company he co-founded in 2008, MC10, is now manufacturing electronic circuits that can be woven into fabrics, molded onto flexible devices, or even adhered to body parts. The Cambridge (Mass.) startup plans to introduce its first product, electronic sportswear capable of measuring heart rate, joint strain, and other physical data, next year in a partnership with Reebok. That’s just the “lower-hanging fruit” of several products in development, says Rogers.
After earning a PhD from the Massachusetts Institute of Technology in 1995 and doing post-doctoral work at Harvard, Rogers moved to Bell Labs and started hunting for a way to make flexible electronic circuits. Eventually he left for the University of Illinois, where he assembled the research team that “stumbled into the solution,” Rogers says. The process for creating his bendable electronics starts with making ribbons of ultrathin silicon, each 100 nanometers thick, or about 1,000 times thinner than human hair. At that scale, the silicon’s physical properties differ from those of a conventional wafer, allowing it to bend and stretch. The ribbons are assembled into a lattice and then transferred onto a layer of rubber. The result is a flexible, durable semiconductor. Rogers and his team have spent the years since their 2005 discovery refining the circuit creation process to make it suitable for high-volume, low-cost production.
Rogers isn’t the first to develop flexible electronics, but his method produces circuits that can process data as fast as conventional computer chips and are 1,000 times faster than other flexible microprocessors, he says. Most of the alternatives don’t contain silicon, so they “don’t have the kind of functionality he can incorporate,” says Zhenan Bao, associate professor of chemical engineering at Stanford University. Earlier this year, Rogers was awarded the $500,000 Lemelson-MIT Prize, which is administered by MIT’s School of Engineering and considered the Oscar for inventors.
Rogers says MC10—the name stands for Materials Company 10, a reference to the number of companies Rogers and his four co-founders have worked at—has contracts with the U.S. military to adapt its technology for use as photovoltaic “skin” that could power an unmanned aerial vehicle. The company is also exploring health-care applications. It’s working with Massachusetts General Hospital to put the stretchy microprocessors on the tips of cardiac catheters, which are threaded through arteries into the heart. The smart catheters will at first monitor electrical activity and help doctors pinpoint the location of irregular heartbeats, and could eventually help treat such arrhythmias by zapping malfunctioning tissue. That and other medical applications “could really change the way you think about electronics and biology and how you bring those two things together,” says Rogers.