An American Chemical Society video surprises everyone with an exciting prospect: Terminator-like liquid metals that can change shape, stretch, and move.
The study conducted by researchers from the universities in Beijing, China, can play a vital role in enhancing soft robotics technology.
Soft robotics is a subfield that takes inspiration from nature. It uses materials that are elastic or non-rigid. Some studies showed it can have multiple applications. These included the capability to work like plant tendrils and gently interact with humans and the environment.
The flexibility of this robot may also be useful in healthcare. In 2017, Harvard University and Boston Children’s Hospital developed a proof of concept, showing a soft robot acting like a normal beating heart.
For the experiment, the scientists didn’t rely on a new concept. Instead, they applied their knowledge in material science and became more creative.
Some metals such as gallium and other alloys are liquid when exposed to room temperature. They are also highly conductive and easily deformed. They also possess a low melting point, making them ideal as materials for electronics.
When one combines magnetic particles, it becomes possible to manipulate the liquid metal. The problem was it could only stretch horizontally because of the high surface tension. The material could also change into paste unless submerged into a fluid.
To get past these challenges, the researchers decided to use hydrochloric acid as the submersible liquid. They then worked on the droplet of three liquid metals: tin alloy, indium, and gallium.
They created an oxide layer on the droplet’s surface by adding the iron particles. The layer helped reduce the surface tension, making the liquid metal more “flexible.” The researchers used a pair of magnets placed on each end to move the metal.
Moving, Walking Liquid Metal
With manipulation, the scientists were able to connect two submerged horizontal electrodes and even light a bulb because the metal has high conductivity. It also stretched horizontally and vertically, extending its resting length almost up to four times.
Even amazing, when the liquid metal was vertically stretched, it still moved horizontally. Half of it was in hydrochloric acid while the other was already exposed to air. It’s similar to an amphibian walking on water.
“With all the appealing properties, this MLMD presents a fundamental and promising platform for the liquid metals to further develop the multi-freedom actuation in free space and eventually lead to the dynamically reconfigurable intelligent and biomimetic soft robots in the future,” said the study now published in Applied Materials & Interfaces.
Soft robotics still has a long way to go to become as efficient as their strong counterparts. Who knows, though, it may not be that long.
Watch the Terminator-like liquid metal move in this YouTube video from the American Chemical Society: