Liquid metal paddle motor demonstration: https://youtu.be/KfX9ABh4dH4
UNSW researchers create the world’s first motor that spins using a droplet of liquid metal, opening new possibilities for soft robotics and flexible machines.
Researchers at UNSW have developed a new type of motor that spins, not with rigid components, but with a droplet of liquid metal.
The breakthrough could transform soft robotics, flexible electronics, and medical devices.
The tiny motor, called a liquid metal droplet rotary paddle motor, works in a completely new way. Instead of traditional, rigid components like coils or magnets, the motor produces rotation by using swirling flows inside a droplet of liquid metal that is embedded in a salt solution and exposed to an electric field.
A small copper paddle placed within the swirling metal is carried along by these internal flows, creating rotation.
“This is a completely new way to create motion,” said Dr Priyank Kumar, who supervised the project and corresponding author of a paper published in npj Flexible Electronics.
“We’re harnessing the flow of liquid metal itself to produce rotation, without any traditional moving parts. It’s simple, compact, and inherently flexible.
“Reaching speeds of 320 revolutions per minute, our motor sets a new benchmark for liquid metal actuators. It proves that simple, flowing metals can drive rotation and opens the door to an entirely new class of motors.”
For many people, motors are part of daily life, often without us noticing. They make our phones vibrate, spin the cooling fans in our laptops, and adjust the focus in cameras.
These rotary motors convert energy, whether electricity or mechanical flow, into torque, which keeps shafts turning and powers everything from washing machines to drones.
Since so many devices rely on spinning motion, any new approach to making motors could reshape machines in our homes, in industry, and even in medicine.
The liquid motor could be especially valuable in applications where traditional rigid components are unsuitable. Soft robotics, for instance, often require machines that can bend, stretch, or squeeze into confined spaces.
Rigid gears and shafts make this difficult, but a motor that is itself soft and adaptable could open up entirely new ways to design robots.
“Imagine a tiny robot that can move through narrow, irregular spaces inside the human body, powered by motors that are soft and flexible rather than hard and fragile,” said University of Sydney Professor Kourosh Kalantar-Zadeh, a collaborator on the project. “That’s the kind of future this technology points to.”
PhD student Richard Fuchs, who developed the motor, said: “The beauty of this design is its simplicity, it’s like a miniature waterwheel. Similar to how flowing water pushes the blades of the wheel, the swirling liquid metal pushes the copper paddles.”
Beyond robotics, liquid metal motors could be used in flexible electronics, microfluidic devices, and biomedical implants, where compact, self-contained motion is required in confined or delicate environments.
Their simplicity and adaptability could allow engineers to build machines that were previously impossible.
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