Scientists discover a material that can be made like plastic but conducts like metal

A group of scientists at the University of Chicago have found a way to create a material that can be made like plastic but conducts electricity more like metal. Above, members of the Anderson Lab at work. Credit: John Zich/University of Chicago

Scientists at the University of Chicago have discovered a way to create a material that can be made like plastic but conducts electricity more like metal.

The study, published on October 26 in nature, shows how to make a kind of material in which the molecular fragments are jumbled and disordered, but which can still conduct electricity extremely well.

This goes against all the rules we know about conduction – for a scientist it’s like seeing a car moving on water and still going 70 miles an hour. But discovery can also be extremely useful; if you want to invent something revolutionary, the process often first begins with the discovery of an entirely new material.

“Fundamentally, this opens up the design of a whole new class of materials that conduct electricity, are easily shaped, and are very robust in everyday conditions,” said John Anderson, associate professor of chemistry at the University of Chicago and senior author of the study. “Essentially, this offers new opportunities for a very important technological group of materials,” said Jiaze Xie (Ph.D. ’22, now at Princeton), first author of the paper.

“There is no solid theory to explain this”

Conductive materials are absolutely essential if you’re making any kind of electronic device, whether it’s an iPhone, a solar panel, or a TV. The oldest and largest group of conductors are metals: copper, gold, aluminum. Then, about 50 years ago, scientists were able to create wires made from organic materials using a chemical treatment known as “doping,” which injects different atoms or electrons through the material.

This is an advantage because these materials are more flexible and easier to process than traditional metals, but the problem is that they are not very stable; they can lose their conductivity if exposed to moisture or if the temperature gets too high.

But essentially, both organic and traditional metallic conductors share a common characteristic. They are made up of straight, closely packed rows of atoms or molecules. This means that electrons can easily flow through the material, much like cars on a freeway. In fact, scientists believe that material there was to have these straight, ordered rows to conduct electricity efficiently.

Xie then began experimenting with some materials discovered years ago but largely ignored. He strung nickel atoms like pearls on a string of molecular beads made of carbon and sulfur and began testing.

To the amazement of scientists, the material easily and strongly conducts electricity. Moreover, it was very stable. “We heated it, cooled it, exposed it to air and moisture, and even dropped acid and base on it, and nothing happened,” Xie said. This is extremely useful for a device that needs to function in the real world.

But for the scientists, the most striking thing was that the molecular structure of the material was disturbed. “From a fundamental picture, it shouldn’t be a metal,” Anderson said. “There is no solid theory to explain this.”

Xie, Anderson and their lab worked with other scientists at the university to try to understand how the material could conduct electricity. After tests, simulations and theoretical work, they believe the material forms layers, like sheets in lasagna. Even if the sheets rotate sideways, no longer forming a neat pile of lasagna, the electrons can still move horizontally or vertically—as long as the pieces are touching.

The end result is unprecedented for a conductive material. “It’s almost like conductive Play-Doh—you can smear it on a spot and it conducts electricity,” Anderson said.

Scientists are excited because the discovery suggests a fundamentally new design principle for electronic technology. Wires are so important that virtually every new development opens up new lines for technology, they explained.

One of the attractive features of the material is the new processing possibilities. For example, metals usually have to be melted down to be made into the right shape for a chip or device, which limits what you can do with them because the other components of the device must be able to withstand the heat required to process these materials.

The new material has no such limitation because it can be made at room temperature. It can also be used when the need for a device or parts of a device to withstand heat, acid or alkali, or humidity has previously limited the ability of engineers to develop new technology.

The team is also exploring the different forms and functions the material can take. “We think we can make it 2D or 3D, make it porous, or even introduce other features by adding different linkers or nodes,” Xie said.

An unusual material could improve the reliability of electronics and other devices

More info:
John Anderson, Intrinsic Glass-Metal Transport in an Amorphous Coordination Polymer, Nature (2022). DOI: 10.1038/s41586-022-05261-4.

Courtesy of the University of Chicago

Quote: Scientists discover material that can be made like plastic but conducts like metal (2022, October 26) retrieved October 26, 2022 from -plastic-metal.html

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