New type of metallic plastic can be sprayed on and made from chains of polymers

Scientists at the Anderson Laboratory at the University of Chicago have discovered a metallopolymer that can be made into various shapes, and remains stable in almost any environment.

It's a plastic material

A plastic material has been discovered that has metallic properties and remains stable when chilled, heated, left out in the air, or exposed to acid. Researchers are saying it could prove valuable in medical devices that are wearable, or other kinds of wearable electronics.

“It’s a dark black powder. However, when we put it on a surface as a film, or press it like Play-Doh, it becomes iridescent and shiny,” said Dr. John Anderson, senior author of the research from the University of Chicago.

“From what we can tell, it’s stable up to [about] 250 degrees Celsius,” he added, and did make a note of mentioning the material has conductive properties similar to graphite.

Conductivity

Electrical conductivity is present in materials where electrons move freely. This has been seen traditionally as a key feature of solid conductive materials in an ordered structure.

In this new substance, a metallopolymer formed of chains of molecules made of sulfur, carboxin and hydrogen that carry nickel at regular intervals, has been shown to be highly conductive, although it is amorphous.

Questions remain

The research team was unable to find one solid theory on why this occurs in this material, but they hypothesize that chains of polymers form a disordered stack. This could be likened to a messy pile of playing cards.

The stacks pack together in a disordered fashion creating a material that is amorphous, but allows free flow of electrons both vertically and horizontally.

“While we don’t have a really clear picture yet, we think that the molecular design of the chains enables strong overlap and metallic character, even when it’s disordered and amorphous,” said Anderson.

The researchers have said there are a number of applications for the material.

“We envision that these materials can be more robust electrical conductors, and they may be easily sprayed or painted onto surfaces or other devices,” said Anderson.

Abstract

Nature | www.nature.com | 1ArticleIntrinsic glassy-metallic transport in an amorphous coordination polymer. Jiaze Xie1, Simon Ewing1,2, Jan-Niklas Boyn1,2, Alexander S. Filatov1, Baorui Cheng1, Tengzhou Ma3, Garrett L. Grocke3, Norman Zhao1, Ram Itani1, Xiaotong Sun4, Himchan Cho1,5, Zhihengyu Chen6, Karena W. Chapman6, Shrayesh N. Patel3, Dmitri V. Talapin1,2,3,7, Jiwoong Park1,2,3, David A. Mazziotti1,2 & John S. Anderson1 ✉Conducting organic materials, such as doped organic polymers1, molecular conductors2,3 and emerging coordination polymers4, underpin technologies ranging from displays to flexible electronics5. Realizing high electrical conductivity in traditionally insulating organic materials necessitates tuning their electronic structure through chemical doping6. Furthermore, even organic materials that are intrinsically conductive, such as single-component molecular conductors 7,8, require crystallinity for metallic behaviors. However, conducting polymers are often amorphous to aid durability and processability9. Using molecular design to produce high conductivity in undoped amorphous materials would enable tunable and robust conductivity in many applications10, but there are no intrinsically conducting organic materials that maintain high conductivity when disordered. Here we report an amorphous coordination polymer, Ni tetrathiafulvalene tetrathiolate, which displays markedly high electronic conductivity (up to 1,200Scm−1) and intrinsic glassy-metallic behaviors. Theory shows that these properties are enabled by molecular overlap that is robust to structural perturbations. This unusual set of features results in high conductivity that is stable to humid air for weeks, pH 0–14 and temperatures up to 140°C. These findings demonstrate that molecular design can enable metallic conductivity even in heavily disordered materials, raising fundamental questions about how metallic transport can exist without periodic structure and indicating exciting new applications for these materials.