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Miniaturization to the Max: Nanotech Pioneer Lauded

John Roach
for National Geographic News
October 10, 2003
 
Machines, medicines, and materials a mere fraction the width of a human hair may one day store trillions of bits of information, detect the onset of cancer, and restore a paralyzed limb.

But before the promise of nanotechnology is even modestly met, scientists must first learn how to make three-dimensional structures and tools at a scale much too small for even the deftest robots or nimblest human hands to manipulate.


George Whitesides, a chemist at Harvard University in Cambridge, Massachusetts, is on the job. On November 10 he will be awarded the 2003 Kyoto Prize for Lifetime Achievement in Advanced Technology for, among a myriad of accomplishments, laying the foundation for building nanostructures.

Nanotechnology gets its name from a unit of measurement known as the nanometer, which is one billionth of a meter. To put the dimension in perspective, a human hair is about 100,000 nanometers thick.

Whitesides is being recognized for pioneering advances in material sciences that increased understanding of how molecules can assemble themselves and how such assembly can be applied to building devices that are measured in nanometers.

"Materials are very important—they are the stuff out of which everything is made—but they are often invisible to the user. So they are a foundation for technology, not the visible part," said Whitesides.

The Kyoto Prize, one of three to be awarded in Japan for significant contributions to the scientific, cultural, and spiritual development of humankind, comes with a gold medallion and check worth about U.S. $400,000.

"[I'm] pleased, of course, what else?" said Whitesides about the honor. "But for the research group—this is an award that [goes] to a substantial number of people."

The nod is to about 50 graduate students, postdoctoral researchers, and visitors that work in his laboratory at Harvard, which is one of the largest and best funded nanotechnology-related labs in the U.S., according to Mihail Roco, the senior advisor of nanotechnology at the National Science Foundation in Arlington, Virginia, and leader of the National Nanotechnology Initiative.

Multidisciplinary Area

Roco oversees the more than U.S. $700 million the U.S. government now spends on nanotechnology research each year. He said part of Whitesides' success in obtaining a hefty slice of the pie is the ease with which he moves between the various disciplines that make up nanotechnology.

"He is certainly good in chemistry—his original interest—but he moves very easily to fluidic devices, systems engineering, electronics, and many other fields," said Roco. "This is part of his success and recognition."

Whitesides received his bachelor's degree in chemistry from Harvard in 1960 and his Ph.D. in 1964 from the California Institute of Technology. Prior to joining Harvard's chemistry department in 1982, he was a member of the faculty at the Massachusetts Institute of Technology.

While a chemist by training, Whitesides said success in nanotechnology requires a solid grasp of all the core sciences. For example, he said that biology is a master at making nanomachines such as the light-harvesting apparatus of green plants, and thus it is important to understand biology so as to understand nature's designs.

"I would say that we need chemistry to make things, biology to teach lessons about what to make, materials science to use the materials, and physics to measure the properties," he said. "It's a multidisciplinary area."

Self Assembly

One of Whitesides' seminal works is a 1989 paper published in the Journal of the American Chemical Society in which he describes how to control the self-assembly of a single layer of molecules, called a monolayer.

"The reason it is important and recognized is that it is a foundation of more complex systems," said Roco. For example, in theory three dimensional structures could be built in layers like rows of bricks stacked on one another to build a house.

The self-assembled monolayer (SAM) process allows scientists to choose the chemical composition of the monolayer, thus choosing the properties of the surface it creates, and control how the molecules self-arrange.

"Self-assembled monolayers are highly ordered monolayers—the molecules are arranged in a pattern with each, at least within a region, in the same orientation. That is, they are crystalline or close to it," said Whitesides. "Because they are regular and because they are very easily made they are essentially ideal as a system with which to study surfaces."

The science of surfaces is central to Whitesides' work. He considers them a form of matter distinct from liquids, solids, and gases. They are what give everything shape and determine properties such as whether or not an object is resistant to water.

"Surfaces are very important in many technologies, especially in the technologies of small things [like] microsystems and nanosystems," said Whitesides.

Whitesides recently advanced his self-assembled monolayer (SAM) technology to develop soft lithography, which is a set of techniques based on the same principles as a mold for an automobile or a rubber "confidential" stamp for an envelope, to make micro and nanostructures.

The technique produces structures similar to those made by photolithography, which is the basic technology for making microelectric devices such as semiconductors.

"Soft lithography is just beginning its development and I do not think it will take over from photolith for high performance microelectronics. But it is much less expensive than photolith and it can handle a larger range of classes of materials," said Whitesides.

The drug industry, for example, is using soft lithography to make tools that will help in the development of new drugs. Researchers are also adapting the technique to make a new class of organic microelectronics.

In the meantime, Whitesides will continue to pioneer advances in materials science. "I like discovery and I like problem solving," he said. "It's fun and sometimes useful."
 

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