Let's face it. We've all dreamed of rocking an invisibility cloak, but so far scientists just haven't delivered. Well, now, with the help of some biomimicry, we could see something similar in the not too distant future.
Scientists at the University of Bristol are taking inspiration from two of the best camouflage artists in nature, the squid and the zebrafish, to create color-changing technology that could lead to smart clothing and other fabrics that can instantly change to match the color of their background.
Many cephalopods like squid and cuttlefish are able to quickly blend in with their surroundings by changing color. This process is made possible by chromatophores, cells that contain a sac filled with pigment. When the squid's muscles surrounding a cell contract, the sac is squeezed to appear larger, creating an optical effect that makes the squid look like it's changing color.
Zebrafish, on the other hand, also have chromatophores, but theirs contain liquid pigment that when activated comes to the surface and spreads out like spilled ink. The dark spots on zebrafish appear to become larger, altering its appearance.
The Bristol team was able to replicate both of these amazing processes by using dielectric elastomers, stretchy polymers that expand when hit with an electric current. To mimic the squid's color-changing muscles, the scientists applied electric current to the elastomers, causing them to expand just like the squid's pigment-filled sacs. When the current stops, the elastomers return to their normal size.
To mimic the zebrafish, the team had to be a little more creative. They sandwiched a silicone bladder between two glass microscope slides with dielectric elastomers connected on each side of the bladder with silicon tubes. The dielectric elastomers acted as pumps for either an opaque white liquid or water tinted with black ink. Each pump can be activated with electric current to send its colored liquid into the bladder and displace the other color, creating a color-changing effect.
Other than being a really cool science experiment, this biomimetic artificial muscle technology could have some neat applications. Project lead Jonathan Rossiter said “Our artificial chromatophores are both scalable and adaptable and can be made into an artificial compliant skin which can stretch and deform, yet still operate effectively. This means they can be used in many environments where conventional 'hard' technologies would be dangerous, for example at the physical interface with humans, such as smart clothing.”
If you've ever just wanted to blend in with the wall, you may have your chance soon.