After observing the mechanisms of color-changing cephalopods like squid and zebrafish, the team was able to create its own brand of camouflaging artificial muscles. The squid-inspired technology could even someday lead to “smart clothing,” allowing humans a greater ability to blend into the background.
To develop their artificial muscles, the team studied the processes by which squid and zebrafish change color to blend into the ocean’s floor. Both species have unique cells called chromatophores that contain small sacs filled with pigment. When a squid’s muscles surrounding the cell contract, the pressure causes the pigment-filled sacs to squeeze and become larger, making it seem as if the cephalopod has changed color.
Unlike in the cells of squid, the pigment contained in the chromatophores of zebrafish is liquid. The zebrafish change color by pumping the pigmented liquid from under the skin to the surface.
Scientists recreated these two processes by using dielectric elastomers, or malleable polymers that expand when activated by an electric current. To mimic the squid, the team applied the current to the elastomers, which caused them to expand—just like the cephalopod’s pigment.
To recreate the zebrafish’s color-changing mechanisms, the group used elastomer-activated tubes to pump different colored liquids into a small silicone bladder.
"These artificial muscles can replicate the [natural] muscular action… and can have strong visual effects," study author Jonathan Rossiter told the BBC. "This could help us create a whole host of new technologies, ranging from active-camouflage and clothes that change colour and pattern, to a smart second-skin that can cool you when you are hot and keep you warm when you are cold."