Stretchable Silicon Could Make Sports Apparel Smarter
Reebok will collaborate with startup MC10 on wearable electronics to monitor athletic performance.
Stretchable silicon electronics that offer the computing power of rigid chips could make their way into Reebok’s athletic apparel in the coming years. The company will work with MC10, a startup maker of flexible electronics, to develop sportswear that incorporates electronics to monitor athletes’ health and performance during training and rehabilitation.
Reebok and MC10, which is based in Cambridge, Massachusetts, would not provide specifics about what products are under development. Representatives say the goal of the project is to make the interface between people and their electronics disappear. “We want to bring more information to the athlete, using the [conformable electronics] technology in a way that makes the electronics invisible to the user,” says Paul Litchfield, head of Reebok Advanced Concepts.
Textiles incorporating electronics are already available today, for example in sports bras that use conductive textiles to register a woman’s heart rate. But today’s devices connect to a box containing the heart of the electronics, which are built on rigid chips. In the bra, a removable plastic box beams a signal to a watch.
Clothing incorporating high-performance conformable electronics could have many advantages over these systems, says MC10 CEO David Icke. First, the electronics could be totally incorporated into the inside of a shirt, or into a decal placed directly on the skin, without the need for a casing. They could conform to the body, and their increased level of contact with the skin could lead to higher-quality measurements. And by incorporating transistors that can amplify and process signals for better sensitivity, the flexible electronics would deliver more-valuable information. “It’s not like wearing a device with hard segments attached to the body,” says Litchfield.
The athletic-apparel devices might incorporate sensors and a microprocessor to monitor many indicators of an athlete’s health, such as impacts on the body, electrical information from the heart and nervous system, sweat pH, blood pressure, gait, and strain on joints. Such devices could process the data to generate information about metabolism and athletic performance and broadcast it to another device. MC10 says the products could be out within a year or two.
The researcher who cofounded MC10, University of Illinois materials science professor John Rogers, has prototyped sensors, processors, and light-emitting diodes based on silicon and built on thin, lightweight, flexible, and even stretchy materials. Like conventional silicon chips, these flexible electronics are fast and power-efficient. Other flexible electronics, based on organic semiconductors rather than silicon, tend to be slower and more power-hungry. Working with organic materials, researchers at Xerox’s PARC have made printed sensor tape for the U.S. military that’s mounted inside helmets to record blast strength, temperature, and other data, and includes transistors to process the data.
MC10’s devices are made by etching out very thin strips of silicon and printing them onto flexible substrates. This lets them conform to uneven surfaces such as human skin. Rogers notes that other products under development by MC10 include electronics for interfacing between the body’s delicate inner tissues and surgical instruments such as balloon catheters. “From the standpoint of mechanics and materials design, there are many foundational issues common to use inside and outside the body,” he says.
As the performance gap between rigid chips and conformable electronics begins to close, the idea of a wearable computer begins to seem less speculative, says Juan Hinestroza, who heads the Textiles Nanotechnology Laboratory at Cornell University in Ithaca, New York. “Those were impossible dreams, but now we can produce high-performance electronics on flexible substrates,” says Hinestroza, who is not affiliated with Reebok or MC10. “The interface between electronics and garments will disappear,” he predicts.