FYI.

This story is over 5 years old.

Tech

These Color-Emitting Metallic Gels Could Automatically Detect Ocean Pollution

These funky materials glow in different colors as they react to various conditions in their environment.
Glowing materials shown under UV light. Image: Tara Fadenrecht

Imagine a submarine with parts that glow bright yellow as it detects pollutants and toxins in the sea. This might be a possibility if researchers behind a bunch of luminescent materials refine their new metallic gels.

In a study published in the Journal of the American Chemical Society, the researchers describe the material in question as a light-emitting metallogel that's made using rare-earth elements.

Advertisement

What's cool about the material is that it can be engineered to glow different colors in response to different stimuli. The material, said Niels Holten-Andersen, the paper's co-author and assistant professor of materials science and engineering at MIT, were ultra sensitive to their environment.

"We tried to make polymer materials that are held together by chemical bonds that emit colors based on their bond state," he told me over the phone.

The materials can be used as as warning system that emits a colored light as soon as it detects something unusual—whether that be in the form of pollutants or toxins—within its environment. Holten-Andersen explained that this would be useful when it came to detecting things like ocean acidity or salt levels.

The researchers turned initially to the ocean for some design inspiration. Holten-Andersen, who works on bio-inspired polymers, spoke of studying the range of "funky organisms" in the ocean. Mussels might not seem all that exciting, but according to Holten-Andersen, they've figured out things that engineers are still struggling with. "We don't have glues that function underwater, but they've figured that out," he said.

"Nature presents us with macromolecular building blocks that can self-assemble into materials with extraordinary physical properties"

Bio-inspired engineering is a well-established field with well-known examples including octopuses inspiring materials for camouflage suits and squid skin inspiring the possibilities for invisible cloaking for soldiers. In a previous paper, Holten-Andersen and another research team describe why the natural world provides such a good source of inspiration.

"As a result of hundreds of millions of years of molecular evolution in aqueous environments, nature today presents us with macromolecular building blocks that in water can self-assemble into materials with extraordinary physical properties," they write.

Elsewhere, Holten-Andersen points out the challenges still faced by materials engineers, saying that man-made polymer materials can still be water intolerant and in some cases environmentally unfriendly. The main aim, however, writes Holten-Andersen, is to "distill the design strategies evolved through biological material adaptation in Nature and use them to expand the material properties of synthetic polymers."

According to the researchers, their light-emitting materials can currently be made in either gel form or as thin solid films. And both their versatile properties and ease with which they can be assembled suggests they'll be great for engineering "multi-stimuli-responsive polymer materials" in the future.