Thought of using protein powder or creatine to get stronger? Try vanadium dioxide (actually, don’t). A team of researchers with the U.S. Department of Energy (DOE)’s Lawrence Berkeley National Laboratory (Berkeley Lab) has demonstrated a micro-sized robotic torsional muscle/motor made from vanadium dioxide that for its size is a thousand times more powerful than a human muscle, able to catapult objects 50 times heavier than itself over a distance five times its length within 60 milliseconds. That’s faster than you can say “spot me, bro.”

For comparison purposes, that would be like a human tossing a small school bus nearly 30 feet. An impressive party trick, to be sure.

“We’ve created a micro-bimorph dual coil that functions as a powerful torsional muscle, driven thermally or electro-thermally by the phase transition of vanadium dioxide,” says Junqiao Wu, a physicist who holds joint appointments with Berkeley Lab’s Materials Sciences Division and the University of California-Berkeley’s Department of Materials Science and Engineering. “Using a simple design and inorganic materials, we achieve superior performance in power density and speed over the motors and actuators now used in integrated micro-systems.”

Vanadium oxide is a uniquely attractive material for artificial muscles and motors because of its physical properties. When heated rapidly, it contracts along one dimension while expanding along the other two.

“The power density of our micro-muscle in combination with its multi-functionality distinguishes it from all current macro- or micro-torsional actuators/motors,” Wu said.

It also acts as an insulator when cold yet becomes a conductor when hot, which scientists hope will eventually lead to breakthroughs in more efficient electronic and optical devices.

Unlike our organic muscles, which degrade with use, the vanadium dioxide micro-muscles demonstrated reversible  torsional motion over one million cycles with no degradation. They also showed a rotational speed of up to approximately 200,000 rpm, amplitude of 500 to 2,000 degrees per millimeters in length, and an energy power density up to approximately 39 kilowatts/kilogram.

“These metrics are all orders of magnitudes higher than existing torsional motors based on electrostatics, magnetics, carbon nanotubes or piezoelectrics,” Wu says.

“With its combination of power and multi-functionality, our micro-muscle shows great potential for applications that require a high level of functionality integration in a small space,” Wu says.

Let’s hope they resist the urge to scale up the operation and provide it with sentience.