Bio-inspired, soft 'invisibility cloak' developed

Inspired by real-life shy squid, scientists have developed soft 'invisibility cloaks' that can change how they reflect heat, making them undetectable to night vision tools.

The thin swatches can quickly smoothen or wrinkle their surfaces in under a second after being stretched or electrically triggered.

This makes them invisible to infrared night vision tools or lets them modulate their temperatures.

"We've invented a soft material that can reflect heat in similar ways to how squid skin can reflect light," said Alon Gorodetsky, a professor at University of California, Irvine in the US.

"It goes from wrinkled and dull to smooth and shiny, essentially changing the way it reflects the heat," said Gorodetsky.

Potential uses include better camouflage for troops and insulation for spacecraft, storage containers, emergency shelters, clinical care, and building heating and cooling systems.

"We were inspired both by science fiction and science fact - seeing dinosaurs disappear and reappear under an infrared camera in 'Jurassic World' and seeing squid filmed underwater do similar things," said Gorodetsky.

"So we decided to merge those concepts to design a really unique technology," he said.

Made of sandwiches of aluminium, plastic, and sticky tape, the material transforms from a wrinkled grey to a glossy surface when it is either pulled manually or zapped with voltage.

Products that reflect heat, such as emergency blankets, have existed for decades. However, in the past several years, inventors in Gorodetsky's lab and others have pushed to create dramatically improved versions via bio-inspired engineering.

One focus has been to imitate how squid and other cephalopods can nearly instantaneously change their skin to blend into their surrounding environment.

Researchers have successfully created prototypes that can next be scaled up into large sheets of commercially usable material.

"It was hard, especially the first phase when we were learning how to work with the sticky material," said Chengyi Xu, lead author of the study published in the journal Science.

After trial-and-error processes involving thousands of attempts, researchers finally saw the mirror-like coating change when they pulled it sideways.