MIT Stumbles on a Way to Print Flexible Coatings Made of Micromachines

A plastic skin impregnated with printed sensors could be wrapped around an airplane wing, for instance

Microelectromechanical devices (MEMS) have the potential to enable a wide range of nanomachines. Unfortunately, MEMS suffer from the critical drawbacks of an expensive manufacturing process, a high rigidity that restricts their use, and a limited pool of suitable materials for construction. Now, it seems that MIT scientists have accidentally solved all those problems by stamping gold MEMS into a sheet of plastic.

The happy accident occurred while the researchers tried to develop a new method of printing circuits onto plastic. However, after repeated failures, the scientists realized that the metallic spots they hoped would carry a signal were actually small machines.

“The first couple times we did this, we were like, ‘Ah! Bummer, man,'” said Vladimir Bulovi, a professor of electrical engineering at MIT. “And then a light bulb went off, and we said, ‘Well, but we just made the world’s first printed MEM.'”

MEMS Sheet

Plastic sheet with gold MEMS.

By printing a conductive metal onto a sheet of ridged plastic, the MIT researchers created a mechanical actuator that bends when in contact with an electric charge. Conversely, if the material is bent the right way, then the sheet of plastic becomes conductive.

With both conductive and mechanical properties, the flexibility of the plastic substrate, and the ease of manufacturing inherent in the printing process, the MIT scientists created an incredibly versatile product.

For instance, the plastic skin could be wrapped around airplane wings or bridge pylons and send a signal when faced with integrity-jeopardizing deformation. Or, the actuator could serve as a base for more complex nanomachines that sort, build, or transport materials at a tiny scale. In fact, the gold MEMS are so small that sound waves can deform them, opening up the possibility of nano-microphones.

Really, it’s not fair. Even when MIT scientists make a mistake, they end up inventing amazing machines.