In his cramped cubicle at Nanomix, a nanotechnology company in Emeryville, CA, just across the bay from San Francisco, theoretical physicist Seung-Hoon Jhi peers at a computer model of a hydrogen fuel tank, carefully tracking the movement of individual molecules. As he raises the temperature of a simulated sheet of boron and nitrogen atoms from a frigid 50 Kelvin to a slightly less chilly 80 Kelvin, he watches the reaction of a handful of hydrogen molecules dotting its surface. The boron nitride sheet undulates, yet the hydrogen molecules hold fast. It’s an encouraging sign in a virtual experiment that may have just saved weeks or months of painstaking experimental testing in Nanomix’s effort to develop more efficient hydrogen storage materials for fuel cell cars.It’s cyberdreaming, of course. But Jhi and his Nanomix colleagues are so confident in the veracity of this computerized modeling, pieced together from precise calculations of the behavior of individual atoms, that they are using the simulations to design and test materials that have never been made before-materials whose ordering at the nanometer scale (a nanometer is a billionth of a meter) can produce properties useful in applications ranging from ultrasensitive sensors to flat-panel displays to stealthy coatings for war planes. Down the hall, less than 15 meters from Jhi’s cubicle, the company’s experimentalists are busy working in the lab to synthesize the most promising results of the modeling.
While Nanomix is just one of several recent startups hoping to exploit nano materials, the company is betting it has an edge: the skill to both virtually design the materials-without so much as stirring a beaker-and then go into the lab and make them. Its cofounders-theoretical physicist Marvin Cohen and experimental physicist Alex Zettl, both from the University of California, Berkeley-have been collaborating on such alchemy for over a decade. Now they are hoping to leverage that expertise as the basis for a nanotech business. “Our goal is to have the first working nano components on the market,” says Nanomix CEO Charles Janac.
Designing materials on computers has tempted industrial researchers for more than a decade. In theory, at least, the idea is simple enough: using the rules of quantum mechanics it is possible to calculate the behavior of the electrons that swirl around an atom. Given enough computing power, one should be able to use such calculations to design a material atom by atom, building in desirable properties by adjusting the electronic profile. The problem is, the properties of materials result from the interactions of a huge number of atoms. And even today’s most powerful supercomputers struggle with quantum calculations involving more than five or six hundred atoms, severely limiting the ability to design new materials.
But nano materials, which are often isolated molecules-or molecules whose properties arise from limited interactions -make a far easier target for computers. Indeed, in many ways, quantum modeling is turning out to be an ideal way to explore the nano world. The “predictive power” of nano modeling, says James Tour, a chemist and leading nanotech researcher at Rice University in Houston, “is turning out to be tremendous.”
Nanomix believes it is just this predictive power that will allow it to revolutionize the discovery of nano materials. Thanks to a head start from its computer simulations, the company, which started up in 2000, is already engineering tiny gas sensors that use carbon nanotubes-molecules just a few nanometers wide, with walls an atom thick-to detect dangerous gases. By the end of next year, Nanomix plans to begin selling these nanotube-based sensors to detect gasoline vapors-protecting refineries, chemical plants and pipeline stations from leaks. Each sensor should cost 10 times less than a conventional leak detector and operate for a year on a watch battery. Linked to wireless transmitters no bigger than postage stamps, they could be scattered by the tens of thousands, blanketing an industrial facility-or squeezed into leak-prone valves to ferret out failing seals, something not possible with far larger and more expensive conventional sensors.
At the same time, Nanomix is drafting designs for novel nano materials for hydrogen fuel storage-materials with an even greater ability to store hydrogen than the boron nitride sheets on Jhi’s screen. If these materials become reality, they could dramatically increase the performance of fuel cell cars, finally making automobiles that run on hydrogen fuel commercially practical. The company has also begun to ponder how novel nano materials like nanotubes could be used in tiny computing devices.
Nano materials for fuel cells and nano computers will likely take years to develop. But Nanomix believes its plan to begin selling sensors and other early applications of nanotech will make it a viable business long before then. “People keep saying nanotechnology is a long way out, and it is in the sense that it’s a long-term trend that’s going to have a huge impact on the world economy. But some of the early applications are just 18 months away,” predicts Janac.