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​This Next-Gen Cloaking Material Is Made of Synthetic Octopus Skin

It's not exactly field ready, but it does offer a great glimpse into the future.
The mimic octopus. Image: Klaus Stiefel/Flickr

Nature perfected the cloaking device long ago in marine animals like octopi and cuttlefish, which can change skin colour in order to blend into their surroundings. Inspired by these denizens of the sea, an interdisciplinary team of researchers have designed a new heat-sensitive synthetic material that changes colour when exposed to light.

The device consists of a flexible skin that the researchers describe as being similar to a sheet of pixels laid out in a grid. The "pixels" are black at room temperature, but change to white and shades of grey as light crosses them, triggering diodes that raise the pixels' temperature slightly.

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It's not exactly field ready—the material is just one inch square in size right now—but it does offer a peek into how a future cloaking device might work. The researchers say it could be scaled up and wrapped around larger objects as the technology develops.

"This is by no means a deployable camouflage system but it's a pretty good starting point," John Rogers, one of the lead authors of the research paper published this week in the Proceedings of the National Academy of Sciences told National Geographic.

Attempting to understand how undersea cephalopods like octopi and cuttlefish blend into their surroundings has been of some recent interest to scientists. Researchers at the Harvard School of Engineering and Applied Sciences found that the cuttlefish—like other cephalopods—uses a complex system of leucophores, iridophores, and chromatophores to respectively scatter light, reflect it, and produce pigment, which in sum allows the animal to blend into its surroundings.

According to the researchers, their camouflage replicates key elements of cephalopod skin, save for the iridophores and ocular organs. The top layer of the synthetic skin is comprised of cells filled with heat-sensitive dye, which mimics the chromatophores. A lower layer uses a thin piece of silver to create a white background, much like the leucophores.

Light detectors in the pixels tell electrical diodes in the panels illuminated by the silver to heat up, which causes the dye to turn from black to transparent, making them appear white. The device reacts to stimulus remarkably quickly, changing colour in just a matter of seconds, but it's still nowhere near as fast as cephalopod skin.

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Octopi really set the bar high.

Other recent approaches to building invisibility cloaks have involved refracting certain spectrums of light. Though these methods have proven effective enough to be scaled up to larger swaths of material—still only four by four inch squares—they have some issues. For example, by only cancelling out a narrow band of the electromagnetic spectrum, the cumulative effect of all the uncloaked bands could actually make an object appear brighter.

The use of heat-sensitive dye to match an object's surroundings could conceivably resolve these problems, but the possibility is still distant. For one, researchers still have to figure out how to produce more colours than just white, black, and grey—not to mention the fact that this thing can only cloak objects smaller than an inch in size right now.

It's definitely too early to get really excited by the notion of being able to avoid an annoying ex by blending into the walls like some kind of neurotic squid (already a pretty accurate description of myself). But when it seems like one researcher or another is designing a new way to become invisible every couple months—as of last year, China was researching no fewer than 40—one can't help but have their interest piqued by the possibility.