Self-assembling gears to make way for nanomachines
Published 24 July, 2009, 13:20
Material scientists have devised a technique that allows micro and nanoscale gears to assemble themselves, which will be a cheaper alternative to microlithography.
The trick used by Xi Chen and his team at Columbia University in New York City utilises the way a thin copper film coating a polymeric substrate bends as both cool down and shrink, reports New Scientist magazine.
The two materials expand and shrink with the change of temperature at different rates, so the disc-shaped metal film wrinkles into a highly regular pattern, forming the polymer substrate into a gear. Adding a gardening agent afterwards makes it firm enough for practical application.
By controlling the temperature and curvature of the substrate and using different film material, scientists can alter the number, depth and shape of gear teeth. Theoretically, the same principle allows for the production of complex 3D parts.
“As long as one can create a preferred wrinkle direction, all kinds of teeth patterns are possible,” says Chen. “For example, complicated gears with zigzag-shaped teeth.”
So far the team managed to create self-assembling gears at the microscale – 6 to 25 millimeters across, but Chen believes they can be easily made smaller.
Self-assembling nanoscale machines are among the promising fields of material science research today. It is seen as a potentially more flexible approach than etching techniques, like nanoscale lithography, which are widely used currently.
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