AD: What is the artificial muscle made of?
JM: It's composed of an unusual set of polymers that are electronically conductive. Some kinds have the same conductivity as copper.
AD: How strong is this muscle?
JM: If I had a biceps muscle made of conducting polymer, it would be 100 times stronger than a natural biceps muscle of the same dimension, and capable of lifting a peak weight of 220 pounds.
AD: What's revolutionary about the technology behind this artificial muscle?
JM: The first generation of conducting polymers or actuators were based on swelling, much like spaghetti expands as it cooks. Typically, they could grow 2 percent in length. In the new materials, we're looking at how we can make the molecules themselves change shape and we're seeing a 20 percent change in length. They can act like an accordion. When you remove electrons from the polymer's molecular chain, it tends to contract like a more compact accordion. When you put those electrons back in, it expands again, like an extended accordion. It's similar to muscle, which also makes use of small molecular displacements to move.
AD: What could we do with this technology?
JM: Let's say we look at robotics or prosthetics. You don't typically imagine putting an engine like your car's on your arm to make your arm move. Electrical motors can be used, but they tend not to generate a lot of force or torque. Electrical motors are currently used, because until now there has been no other option, but they're not optimal. If we could have something like muscle in those cases, that would be a great advantage.
AD: What are some medical applications?
JM: Let's say we wanted to replace some intestine to help propulse food along. We're working on an artificial urinary sphincter so men who have had their prostates and urinary sphincters removed are not incontinent for life.
AD: What are the consumer applications?
JM: Dispensers for toothpaste or eye shadow or deodorizer are possibilities. When using cosmetics, it's important to control the quantities that are being excreted. At the moment, we don't have motors small enough or cheap enough to do that. There is a large potential for these new materials, as they're lower in cost. Here's another possible application: The motor for your car could be entirely encapsulated in your tire. You could just attach the tire to your car, and that would be where all the forces are generated. That could certainly be possible in 15 or 20 years. This would be a neat way to drive a car â€” through its tires.
AD: How might artificial muscle change the way we live?
JM: An exoskeleton muscle replacement could help the elderly get up out of bed or off the toilet or out of the bath. They would be like Monty Python's super-grannies, who acted like Hell's Angels. If anyone had to move something, such as a washing machine, or carry a heavy load of groceries, this could assist them.
AD: Where might artificial muscle first show up?
JM: In five to six years, it will be in microscale applications or microelectric mechanical systems. The artificial muscle could help pump and mix and control the flow of fluids. It could be used to develop artificial organs or help run labs on a chip. The advantage is that these polymers respond quicker. They also require lower voltage and produce larger forces than what is used now.
Imagine strapping on an outer shell of extra muscle that makes you 100 times stronger. Scientists at Massachusetts Institute of Technology (MIT) are developing a new class of polymers that can be formed into artificial muscle to give ordinary folk super-human strength. This new muscle material could help people lug suitcases, lift groceries from the car trunk or just get out of bed. â€œAnywhere you've got muscle, whether it be skeletal, cardiac or smooth muscle, there's the potential to replace it or enhance it,â€? says John Madden, research scientist and co-director of MIT's bio-instrumentation lab, which is developing this new material.
The artificial muscle is composed of a special type of plastic that conducts electricity. This electrical conductivity can be switched on and off: As electrical charges are added to or removed from the polymer, it changes in dimension, and can then generate force. This material can be adapted to a number of product categories â€” from strap-on muscles to cosmetics dispensers. Madden's lab, for instance, is designing support socks that will massage the leg to prevent blood clots in people at high risk. In the future, artificial muscle could even be used to create underwear to shape the bodies of flabby Boomers.
In 2001, Madden co-founded Molecular Mechanisms, a Cambridge, Mass.-based company, to develop and commercialize the technology. He recently spoke with American Demographics' Sandra Yin about artificial muscle's market potential.