Nanotech: How to Play with Atoms

Chris Wood August 21 2000

Nanotech: How to Play with Atoms

Chris Wood August 21 2000

Nanotech: How to Play with Atoms

Chris Wood

There is small stuff. There is tiny stuff. After that comes microscopic. Then, there is nanostuff: stuff so small it has to be measured in billionths of a metre— nanometres. Four individual atoms of copper, for instance, laid side by side, would measure about one nanometre.

Were talking really small here. Yet researchers around the world are increasingly certain that in this sub-microscopic world lurks technology’s next Really Big Idea. “Over the next decade, nanotechnology is going to have an enormous economic impact,” asserts Martin Moskovits, a professor of physical chemistry at the University of Toronto. “I’m just not sure what.”

That nicely sums up what is fast becoming one of the hottest topics in sci-

ence. In principle, nanoscience and nanotechnology refer to any activity dealing with objects measured in nanometres. In practice, they embrace half a dozen disciplines, and an expanding laboratory tool kit with dazzling potential to manipulate individual atoms and create designer molecules.

The field’s near-term potential lies in great leaps downward in miniaturization, begetting huge gains in efficiency. Sarny Mahmoud, dean of engineering and design at Carleton University in Ottawa, envisages chemical sensors, computers and radio transmitters, together with batteries, in packages the size of sugar cubes that could be dropped into wells to detect contaminants in water at the earliest stage. Longer-term expectations begin to resemble those for the fabled Philosopher’s Stone, sought after by alchemists of the Middle Ages. It was said to turn lead into gold. Nanotechnology won’t quite transform elements. But Honolulu-based NanoTechnology Magazine does predict that “nano-bots” will one day be able to build pretty much anything else we might want, by assembling molecules one atom at a time. “If you wanted to build something out of steel,” the magazine speculates, “you could release nano’ machines into a junkyard to scavenge iron and steel and build your desired structure atom by atom. You want wood? Which do you prefer: mahogany, teak, cherry? Just whip out software for the wood of your choice and press go.”

The alchemists never did find their stone, and most serious

The science of small could create an economic revolution

researchers think it will be a long time—if ever—before nanobots are running up Chippendale chairs from table scraps. But more modest revolutions may well be possible. Incorporating super-strong, nano-engineered molecules in materials used for wings and engine parts, for instance, could make aircraft far stronger and lighter—as well as more powerful and fuel efficient. Paints created with nanotechnology might change colour by altering molecules on their surface. Moskovits foresees nano-devices within a decade, “not assembling a ham sandwich one molecule at a time, but perhaps running through your artery and chipping away plaque.”

Novel as it seems, that is no new idea. It was first floated by Nobel physicist Richard Feynman in a 1959 lecture regarded as the genesis of nano-theory. Feynman asserted that nothing prevented humanity from learning to engineer individual molecules. The 1981 invention of the scanning, tunneling microscope gave research a huge boost. Emitting a stream of electrons from a tip a few atoms wide, the microscope is able to map the bumps and valleys of individual atoms in a molecule. Scientists soon found the electron stream could also be used to push atoms around. In the last decade, chemists, biologists and engineers have joined physicists in an intensifying race to transform Feynman’s ideas into reality.

The results have fuelled broad enthusiasm. Researchers at the University of Toronto are among those worldwide using nanotechnology to create prototype components for new forms of computing based on light instead of electricity (page 30). Scientists are also tackling the mammoth problems raised by teensy weensy components. At Queens University in Kingston, Ont., physicist Alastair McLean fabricates wires only two atoms wide. Such wires might one day be part of minute electronic devices. But mastering nanotechnology is more complicated than merely scaling down existing ideas about electronics. “When you start making things very, very small,” McLean says, “there is no guarantee they behave in the same way they do when you have a lump of them.” Much research is aimed at understanding those differences. Assembling working nano-machines is something else again. “Were a very long way from that point,” says McLean.

‘Vou could release ‘nano’ machines into a junkyard to scauenge iron, and build your structure atom by atom’

Or perhaps not so far. Wielding tools like the tunnelling microscope, scientists are mining many disciplines for clues to nano-advances. Electrical engineers working with organic chemists have created molecules which change shape when exposed to an electric current. That could be used to create molecular equivalents of present-day transistors, diodes or memory chips—with a dramatic difference in size. “If the conventional transistor were scaled up so that it occupied the printed page you are reading,” researchers Mark Reed and James Tour wrote recently in Scientific American, “a molecular device would be the period at the end of this sentence.”

So-called Buckytubes, named after inventor Buckminster Fuller, are nano-scale fibres of carbon stronger than diamonds. Used to reinforce other materials or spun into fibres on their own, they could produce a new generation of super-strong, super-light materials. Meanwhile, University of Toronto chemist Eugenia Kumacheva is developing nano-scale nuggets of latex which can store vast amounts of computer data—or embed secret security codes in paint.

With nanotechnology’s potential growing, funding agencies are ratcheting up support. U.S. President Bill Clinton, earlier this year, announced $750 million for

nanotech research. Ottawa has no matching initiative, but the public-private Canadian Institute for Advanced Research launched a program last year to co-ordinate research from Vancouver to Halifax. The federal and Ontario governments, meanwhile, are investing $8 million to build the country’s first micro-machining laboratory at Carleton University.

There are nano-nightmares, too. Theorists assume building nano-scale devices

one by one will be prohibitively slow and expensive. Instead, an early goal will be one able to reproduce itself into numbers large enough to transform old steel into new Fords. The dark side emerges when someone fails to include an “off” switch. Relentlessly self-replicating nano-bots could transform everything on earth into themselves: a desert of nano-dust.

But nightmare visions more often remain only that. Researchers believe nanotech’s practical promise is far more imminent, and likely to prove irresistible. “It is going to be a major technology,” says McLean. “As big as electronics. We’re all just looking for the first functional device. That will open the door.” Big benefits, in brief, will come in the very smallest of packages. E3