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NotSanguine [soylentnews.org] writes:

Ars Technica is reporting [arstechnica.com] on recently published research [sciencedirect.com] on "smart" materials using liquid metal.

From the Ars Technica article [arstechnica.com]:

While paper isn’t exactly a smart material, it someday could be if it is covered in a new type of liquid metal. This liquid alloy has the potential to turn paper and other materials into gadgets that can do some things on their own.

Liquid metal is already used in smart objects like circuits and wearable sensors—but not as a coating. Inspired by origami [arstechnica.com], a team of scientists led by Bo Yuan of Tsinghua University in China has figured out a way to formulate liquid metal and apply it with a stamp so it sticks to paper without an adhesive, which has never been possible before. In a study [cell.com] recently published in Cell Reports Physical Science, the scientists showed that paper coated in the metal can be crafted into origami shapes and re-fold itself. The metal coating also conducts heat and electricity. It’s like magic. Almost.

Because the particles in liquid metal tend to stay so close together, it is difficult to get it to adhere to any surface without something that acts as glue. But these adhesives usually have a negative effect on the metal’s properties, such as its conductivity [arstechnica.com]. Yuan and his team wanted a liquid metal that could stick to paper without an adhesive. They used an alloy of bismuth, indium, and tin oxide (BiInSn) and tested how well it performed next to an indium/gallium alloy (eGaIn).

BiInSn turned out to be more effective. Unlike eGaIn, it doesn’t oxidize when exposed to air, so how well it sticks to a surface does not depend on the oxide film that forms on the metal. BiInSn is a solid at room temperature and has a higher melting point, so there is no risk of it liquefying at temperatures under 62° Celsius (about 144° Fahrenheit). It is also capable of stronger adhesion. However, getting optimal adhesion out of BiInSn required trial and error.

“We needed to ensure the adhesion of liquid metal to be uniform in large scale on different paper, and to maintain the stability of the coating,” Yuan told Ars Technica in an email interview. “To solve these problems, we changed pressure applied on the stamp as well as the rubbing speed used in the experiments and finally found the most suitable parameters, which finally achieved fast, large-scale, and stable adhesion.”
[...]
This substance could possibly be an asset to soft robots in alien environments. Some soft robots can already explore [mdpi.com] the deepest reaches of the ocean where the pressure is too high for humans and the cracks and crevices too small for larger machines. Soft robots are being designed with an eye for subsurface tunnels on Mars [wiley.com] and other bodies in space [wiley.com]. Autonomous soft robots that are thin and flexible would be able [nasa.gov] to venture into places where larger rovers are unable to fit or navigate safely, and the self-adhesion of the liquid metal coating would allow them to fold and unfold on their own.

Are we going back to physical newspapers, then? With the "subscription" being the purchase of a single "smart" newspaper that resets every day with the next edition?

DOI: 10.1016/j.xcrp.2023.101419 [doi.org]

Original Submission