Arthur Clarke's Third Law. Do you remember her? “Any sufficiently advanced technology is indistinguishable from magic.” This is why researchers are a bit like modern magicians, capable of transforming reality with the "powers" of scientific thought. Their latest magic? Finding ways to apply liquid metal to surfaces such as paper and plastic, transforming these everyday materials into potential "smart devices".
Liquid metal uber alles
The ace in the hole is a technique developed by a team of Chinese scientists, which consists of "tying" the liquid metal to common materials such as paper and plastic. As? without using glues, simply by exerting pressure on the surfaces to be "covered".
The research, published June 9 in the journal Cell Reports Physical Science (I link it to you here), shows how this technique is already thought to work on a large scale and could have applications in wearable devices, flexible accessories and soft robotics.
A surprising discovery
“We thought it was impossible for liquid metal to adhere so easily to non-wetting surfaces,” he says Boyuan, a scientist at Tsinghua University and first author of the study. “We achieved this by simply regulating the pressure, which is very interesting.”
The problem was the very high surface tension of the liquid metal, which prevented it from bonding with most materials, including paper. The solution adopted until now has been to use a method called “transfer printing”, which involves the use of a third material to adhere the metal to the surface.
However, this entailed some disadvantages: more complicated processes and a possible reduction in the electrical, thermal and mechanical performance of the final product.
Overcoming obstacles
To overcome these difficulties, Yuan and his colleagues pioneered an alternative approach. They tried to directly print liquid metal onto various substrates, without sacrificing the properties of the metal. After much trial and error, they managed to find the right parameters to achieve stable and repeatable adhesion. The key? Rub the liquid metal covered stamp onto the surface of the paper or fabric with a little force.
This is just the beginning. The team plans to develop the method further, to apply the liquid metal to a wider range of surfaces, such as ceramic.
“In the future,” Yuan said, “we plan to build intelligent devices using materials treated with this method.”
Apparently the future is already here, and it's coated in liquid metal.
