A close up the new smart skin (Image credit: ACS Nano)
Scientists have been making strides in creating color-changing smart skin that can be applied to various applications, but it hasn’t been easy. Current smart skin isn’t very strong and changes its size after being exposed to different temperatures. Now, a group of researchers has made a breakthrough in smart skin. Khalid Salaita and his colleagues have created a new smart skin that changes color but doesn’t change size. How did they make the discovery? By studying videos of chameleons.
"Watching a chameleon change colors gave me the idea for the breakthrough," study author Yixiao Dong, a doctoral candidate in chemistry at Emory University, said in a news release. "We've developed a new concept for a color-changing smart skin, based on observations of how nature does it."
Chameleons are able to change their color because of the photonic crystals in their skin. When they tense and relax their muscles, light reflects in a different pattern which changes their color. Scientists have been trying to recreate this process, but synthetic color-changing skin often shrinks because of the hydrogel that the photonic crystals are housed in.
The team watched videos of chameleons changing color and noticed how parts of the lizard’s skin are covered by patterns of photonic crystals. This gave them the idea to pack fewer photonic crystals into the hydrogel layer and then place that on a larger layer of colorless hydrogel. They also designed a second hydrogel to accommodate the movement of the crystal arrays. By doing this, the smart skin was able to expand and contract without issue. The smart skin was cut into fish and leaf shapes and was placed outside where they change from orange to green in the sunlight without changing size.
The study was published in ACS Nano, a peer-reviewed journal based on nanotechnology. The journal notes that this new skin can be used for many applications, such as camouflage, signaling, anti-counterfeiting tags, and chemical sensing. It could even be applied to smart devices giving you the ability to change the color of gadgets whenever you want. Still, the team has more work to do on the smart skin before it’s ready to be used in the real world.
"We've provided a general framework to guide the future design of artificial smart skins," Dong said. "There is still a long way to go for real-life applications, but it's exciting to push the field another step further.”
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