A new method of creating microscopic structures and machines from plastic opens a vast world of applications

Recent Engineering Science PhD Dan Sameoto holds up a CD with his new dry adhesive film based on the same principle as gecko feet.



October 23, 2008

Everyone remembers the scene in the 1967 movie "The Graduate" when Mr. McGuire takes young Ben aside and says, "I just want to say one word to you...Plastics." Forty years later SFU engineering science graduate Dan Sameoto has brought the amazing potential of plastics to the world of microelectronics.

Micro-electro-mechanical systems (MEMS) are microscopic machines that reside on silicon microchips. Combining gears and actuators as small as a millionth of a meter with electronic components, they sense and interact with the outside world. At this small scale the standard rules of physics do not always hold true. Sameoto’s breakthrough doctoral research into polymer (plastic) MEMS processing has opened a doorway to a host of potential applications in disposable, biological and underwater MEMS.

Plastic MEMS do not corrode like traditional silicon microchips. They are also much cheaper and faster to produce. They are flexible and being plastic, they allow applications beyond anything seen before in microelectronics. For instance, Sameoto has created "dry adhesives" that mimic the stickiness of gecko feet, which allow the creature to walk upside down on ceilings. He uses a plastic mold to form microscopic "mushrooms" on the surface of a silicone rubber sheet. Each mushroom is only about a micron in size, a millionth of a meter (see image at right). The European Space agency contracted Sameoto to develop these adhesives for a climbing robot destined to explore the planet Mars. “Right now it’s better than a Post-it note,” says Sameoto. “We get about half the adhesion pressure of a gecko at this point.”

Originally from Dartmouth, Nova Scotia, Sameoto's research was inspired by the need to create a generalized full plastic MEMS process for teaching. He and his supervisor Ash Parameswaran wanted to solve the biggest problem in teaching MEMS design. Students’ silicon-based chip designs had to be sent away to conventional chip foundries for fabrication. Results took months to return, often beyond the end of the course. Sameoto’s plastic MEMS process creates chips right here at SFU in just days. It’s now used in two electrical engineering courses.

Plastic MEMS are cheap enough that single-use disposable plastic MEMS devices become possible for medical and other biological applications. Sameoto says, "We are taking MEMS out of the sterile environment and bringing them out into the world to make useful real products that we can see and touch and feel." Consider how much has been accomplished with plastics on the macro scale. Sameoto's technology has already led to a patent for a self-assembling microscopic 3D radio antenna.