Sit back and prepare for a journey into the incredible world of “camouflage” ink, where imaginative scientists have drawn inspiration from octopuses to invent extraordinary technology.
A team of researchers from the University of Hong Kong and Xiamen University took inspiration from this complex natural mechanics to create the new iridescent ink. Did I write well? Yes, it is indeed an innovative ink that can change color on request, thanks to the use of microspheres that respond to different wavelengths of light. Like a cybernetic chameleon, its surface can display any color. A real revolution is looming for electronic displays or even for active camouflage systems.
The lesson of the octopuses
I said it, I repeat it, I will always repeat it: blessed be there biomimetics! This brilliant idea also comes from nature. To be precise, from our friends octopuses and squids. These crafty ocean dwellers are famous for their ability to change color thanks to organs called chromatophores: “bags” of pigment that can expand or contract at will. Depending on which color pigments are visible or hidden at any given time, the animal's skin takes on a specific color or pattern. It is from this complex natural mechanism to create the new iridescent ink that scientists took inspiration for their research published in Nature (I link it to you here).
“Camouflage” ink: like a printer. But better!
The ink, which can change on demand, contains titanium dioxide microspheres and cyan, magenta and yellow dyes. This trio will be familiar to you if you have ever changed the ink in your printer, since they are the basic colors used to reproduce other colors through various combinations (together with black they form the CMYK combination dear to many of my colleagues).
In our case, the microspheres are mixed in equal quantities and designed so that the different colors “rise to the surface” or “sink” in response to light. Depending on the wavelengths and intensity of the light, the surface can be induced to show various colors through the same combined effect, producing designs and even images.
What's the catch?
The titanium dioxide in the microspheres creates a redox reaction in response to light sending the microspheres in different directions. For example, green light will bring yellow and cyan beads to the surface to make the surface look green, while magenta beads will sink.
Although there are still some aspects to improve, such as color reproduction and brightness, and the speed of image and color change, these are all areas that will be explored in future works. If successful, this technology could prove useful for new types of displays, e-ink devices and even active optical mimicry. Obrigado, octopuses.
