In late June, a chemical engineer from the University of Delaware filed a patent that described a new generation of microchips. The patent proposes to replace silicon -- which has long served as the basis for microchips -- with another material. And what might this mystery component be? Chicken feathers.
Richard Wool understands that nonspecialists will find this strange. But he's used to it. Wool and his colleagues at the university's ACRES project (Affordable Composites from Renewable Sources) have been developing new uses for plant fibers, oils and resins. Using such raw materials as the humble soybean, Wool and his colleagues are designing prototypes for everything from simple adhesives to hurricane-proof roofs.
The idea of using natural and waste materials in other ways is not new. Henry Ford grew soybeans around his Dearborn, Mich., headquarters, Wool notes, to find a variety he could use to fabricate auto parts. But when World War II broke out, the work was shelved.
In recent years, environmental concerns have spurred broad efforts to use waste materials, said Brian Love, an associate professor of materials science and engineering at Virginia Tech. These efforts have been bolstered by advances in such fields as engineering, materials science, biotechnology and genetic engineering.
Wool's approach is unusual, said Peter Preuss, a plant physiologist and biochemist who directs the EPA's National Center for Environmental Research -- one of the agencies that has funded Wool's work. Unlike many other researchers who start with a waste product and then decide what it might be used for, Preuss said, Wool looks at existing products and tries to find a waste product or an easy-to-grow crop that could be used to fabricate it.
"This is going to lead to sustainable technologies that are very environmentally friendly," Wool said. "They can help ease the global warming situation in at least two ways. Growing the plants will suck carbon dioxide out of the atmosphere, and reducing the amount of petrochemicals that need to be burned will mean less atmospheric carbon in the first place."
Moreover, Wool said, his raw materials -- soybeans, olives, flax -- can be grown easily and cheaply. And by substituting for petroleum-based plastics, renewable products could reduce the nation's dependence on foreign and domestic oil.
The chicken-feather microchip is not as weird as it sounds. A microchip is basically a wafer of silicon inscribed with a dense maze of transistors. For the chip to do its computational magic, electric signals have to travel across these transistors.
These signals travel faster in the presence of some materials than others. Air, for instance, allows the fastest movement of all, because it provides essentially no resistance. When traveling near solids, however, the movement tends to kick up opposing positive charges. These charges can distract the signal from completing its appointed rounds.
Though these signals move more slowly in the presence of silicon than they do in air, silicon offers less resistance than many other materials do. That's why it has been used in microchips for so long. But engineers are always looking for ways to turbocharge their chips. Historically, they have been able to do this by inscribing more transistors into ever-tinier spaces. But some worry that a physical limit may be approaching.
One possible alternative for increasing a chip's speed is finding a quicker material than silicon. So Wool turned to the chicken feather. He knew that feathers contain lots of air; because birds need to fly, their feathers are strong but light, mainly due to their high air content. Perhaps, Wool figured, the presence of air would make electrons travel faster.
Wool's team took chicken feathers and plant oils and molded them into a composite material that approximates the shape and feel of silicon. When the researchers tested it for speed, they found that the composite allowed movement at about twice the rate of silicon. Though that's still slower than the speed in air, Wool said, "I was jumping up and down."
Energy Department chemical engineer Mark Paster noted that Wool's results are "preliminary" and "a long way from going commercial." But he added that "if they hold up, they are very intriguing."
Wool acknowledged that the future of the chicken-feather chip technology is very much a "wild card." Not only would the microchip industry have to change its production methods, but other alternatives may also exist. Wool said researchers have been trying to introduce "micro-bubbles" into silicon to achieve the same effect as his chicken feathers. Wool speculates that those bubbles "should work fine -- maybe as well as our own composite does."
Even if the chicken-feather chips don't catch on, Wool has lots of other ideas. About five years ago, his team began to develop a soybean-based composite for use in John Deere harvesters. Deere & Co. made its first prototypes three years ago and began full-blown production last year.
Wool is also working with a carmaker -- he won't name which one -- to replace petroleum-based components, such as those made of plastic, with renewable materials. In a similar vein, he's collaborating with Tyson Foods Inc. to make renewable-based replacement parts for the company's fleet of 3,000 Mack trucks. In an effort to use "every part of the bird," Tyson is working with a number of scientists, including Wool, to develop alternative products made from chicken feathers, said spokesman Barry Griffith.
Vehicle parts are a natural focus for such research, Wool said. "The greatest thing for a truck or a car from an environmental point of view is to make it lightweight, because you'll make a significant impact on fuel consumption," he said. "You wouldn't build a truck out of feathers -- it sounds outrageous -- but you could build non-load-bearing parts from them. You'd even get great sound damping."
Historically, the market for alternative technologies has been something of a Catch-22. A new product's price tag inevitably drops as production levels increase -- but those production levels can be hard to achieve early on, when market prices are relatively high. For the moment, "green" marketing is helping Wool sell the idea to early adapters such as Deere and Tyson.
But Wool said he knows that full utilization will require more than that. Corporate manufacturing processes tend to be static, because managers prefer to stick with techniques they know well, rather than chance it with new methods. EPA's Preuss added that creating an infrastructure to collect waste or biomass materials has sometimes proved costly.
"In the end, the only thing private industry is interested in is making money, so the question is whether systems he's developing will be cost-competitive with the systems they're replacing," said the Energy Department's Paster. "The answer, we believe, is that there's a very good chance. That's why we're funding his work."
