They discover a material that is manufactured like a plastic but conducts electricity like a metal


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

The research, published in the journal Nature, shows how to make a type of material in which the molecular fragments are mixed up and out of order, but which can still conduct electricity extremely well.

As the researchers explain, this goes against all known rules about conductivity and could be extraordinarily useful.

“In principle, this opens up the design of a whole new class of materials that conduct electricity, are easy to mold, and are very robust under everyday conditions,” explains John Anderson, associate professor of chemistry at the University of Chicago and lead author of the study. study. “Essentially, it suggests new possibilities for a group of materials of great technological importance,” adds Jiaze Xie, a Ph.D. now at Princeton and first author of the work.

Conductive materials are absolutely essential to making any type of electronic device, be it an iPhone, a solar panel, or a television. By far the oldest and largest group of conductors is the metals: copper, gold, and aluminum.

Then, about 50 years ago, scientists managed to create conductors made from organic materials, using a chemical treatment known as “doping,” which sprinkles different atoms, or electrons, through the material. They point out that this is advantageous 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 fundamentally, both these organic and traditional metallic conductors share a common characteristic. They are made up of rows of atoms or molecules that are straight and close together. This means that electrons can easily flow through the material, like cars on a highway. In fact, scientists used to think that a material had to have these neat, straight rows to conduct electricity effectively.

So Xie began experimenting with some materials discovered years ago but largely ignored. He placed nickel atoms like beads on a chain of molecular beads made of carbon and sulfur, and began testing.

To the amazement of scientists, the material conducted electricity easily and strongly. Also, it was very stable. “We heated it, cooled it, exposed it to air and moisture, and even dripped acid and base on it, and nothing happened,” Xie recalls. “This is hugely useful for a device that has to work in the real world.” “.

But for scientists, the most surprising thing is that the molecular structure of the material was disordered. “From a fundamental point of view, that shouldn’t be a metal,” says Anderson. “There’s no solid theory to explain it.”

Xie, Anderson and their lab worked with other scientists at the university to try to understand how the material can conduct electricity. After tests, simulations and theoretical work, they believe that the material forms layers, like lasagna sheets. Although the sheets rotate sideways, no longer forming a neat lasagna stack, the electrons can continue to move horizontally or vertically, as long as the pieces touch.

The end result is unprecedented in a conductive material. “It’s almost like conductive putty: you can squish it into place and it conducts electricity,” says Anderson.

Scientists are excited because the discovery suggests a fundamentally new design principle for electronic technology. Drivers are so important that virtually any new development opens up new avenues for the technology, they explain.

One of the most attractive features of the material is the new processing options. For example, metals often have to be melted down to form a chip or device into the proper shape, which limits what can be done with them, as other device components have to be able to withstand the heat required to process these materials. .

The new material does not have that restriction because it can be manufactured at room temperature. In addition, it can be used where the need for a device or device parts to withstand heat, acid/alkalinity, or moisture has previously limited engineers’ options for developing new technology.

The team is also exploring the different forms and functions the material could have. “We think we can make it two-dimensional or three-dimensional, make it porous, or even introduce other functions by adding different linkers or nodes,” Xie concludes.