This achievement could pave the way for a revolution in the fields of flexible robotics, foldable electronics, and medical devices.
Researchers described a rotating vane motor powered by a droplet of liquid metal in the journal npj Flexible Electronics, asserting that it is based on an entirely new principle. Instead of relying on traditional solid components such as coils or magnets, the rotation is generated by eddy currents within a droplet of liquid metal , placed in an electrolyte solution through which pulses of electric current pass.
A droplet, formed from a gallium-indium alloy, acts as the working element of the motor. The electric field within it generates a Marangoni effect, which consists of vortices that rotate the copper rotor. The voltage is periodically switched off to allow the alkaline solution to dissolve the oxide layer that has formed.
Chemical engineer Priyank Kumar from the University of New South Wales, who oversaw the project, confirmed that this method is completely new for generating motion, saying:
"We use liquid metal flows to achieve rotation without relying on any conventional moving parts. The design is simple, compact, and inherently flexible, providing speeds of up to 320 rpm, and our motor sets a new standard for liquid metal motors. It proves that liquid metals are capable of generating rotation and opens the door to a whole new class of motors."
A liquid metal drive could be particularly useful in applications where traditional rigid components are unsuitable. For example, flexible robots often require machines that can bend, extend, or retract to access tight spaces, something that rigid gears and shafts struggle to achieve. A drive with flexibility and adaptability could open up new possibilities in the design of such robots.
In addition to robotics, liquid metal actuators could find applications in foldable electronics, precision instruments, and biomedical implants, where autonomous and compact movement is required in confined or sensitive environments. The simplicity and adaptability of these actuators could allow engineers to develop machines that previously seemed impossible.
