Berkeley Lab reports the creation of a powerful microscale actuator that can deliver three orders of magnitude greater force per weight than human muscles. The tiny actuators are only about 100 microns in size and made from vanadium dioxide. They could potentially replace less-powerful piezoelectric actuators, which are complicated to make and require toxic materials. From the abstract of the researcher's report:
Here we demonstrate a set of microactuators fabricated by a simple microfabrication process, showing simultaneously high performance by these metrics, operated on the structural phase transition in vanadium dioxide responding to diverse stimuli of heat, electric current, and light. In both ambient and aqueous conditions, the actuators bend with exceedingly high displacement-to-length ratios up to 1 in the sub-100 μm length scale, work densities over 0.63 J/cm3, and at frequencies up to 6 kHz. The functionalities of actuation can be further enriched with integrated designs of planar as well as three-dimensional geometries. Combining the superior performance, high durability, diversity in responsive stimuli, versatile working environments, and microscale manufacturability, these actuators offer potential applications in microelectromechanical systems, microfluidics, robotics, drug delivery, and artificial muscles.
More details can be found in the paper, Giant-Amplitude, High-Work Density Microactuators with Phase Transition Activated Nanolayer Bimorphs (PDF format) and the Physical Review Letters report, "Decoupling of Structural and Electronic Phase Transition in VO2" (PDF format). Additional information can be found on the Berkeley Lab's Wu Group webpage. To see some cool video of the microactuators actuating, read on.