I’ve always been a sucker for color-shifting items. As a kid, I thought there was some magic behind it. And now, as an adult, I bought a bunch of “chameleon” pigments for the jewelry I make. It looks pretty and it makes my inner child happy.
Thanks to a team of researchers at MIT, we now have color-shifting stretchy material. It doesn’t only look cool, but it could have many practical applications too. And you know what makes it extra fun for us photographers? It was made relying on a photography technique from the 19th century!
In a paper and a YouTube video, scientist Benjamin Harvey Miller describes the material and how it was made. The material he designed with his team changes color in response to mechanical stimuli, aka stretching. So far, the main barrier to widespread adoption of materials like this has been a lack of manufacturing techniques and the price. Miller and his team wanted to overcome these problems.
The researchers used an adapted Lippmann photography process. While above all a physicist, photographers may know Gabriel Lippmann as the inventor of a color photography method using a single emulsion. His method for reproducing colors is based on the interference phenomenon.
Relying on just a digital projector and commercially available photosensitive elastomers, the MIT team used a modified Lippmann method to create their “chameleon” material. They would stick holographic recording material (the one uses for passport holographs, for example). They would stick it to a reflective surface like a mirror and expose it to light from a desktop projector. After that, they would bond the holographic film onto other materials like textiles or thin sheets of black silicone. And now, when the material is stretched, you can see the color shift.
“Our approach is fast, scalable, affordable and relevant for a wide range of manufacturing settings,” the research team notes. They see the application in various industries, including healthcare, human–computer interaction, and robotics.
The first application the team is looking at is to develop compression bandages. The color shift would help healthcare workers know how much pressure they’ve applied. Similarly, the visual indicator can give you the same information if you apply the bandage yourself. A YouTube commenter suggested another application I find great is strain identification in architecture.