Dynamically tunable IR reflector could adaptively cloak thermally emitting objects
Electrically actuated IR Bragg reflector has tunable spectral range, fast response, stability to repeated cycling.
Inspired by the adaptive skin of squids, Researchers at the University of California, Irvine have created a Bragg-reflector-based surface that changes IR properties when electrically stimulated.1 The thin swatches can quickly change how they reflect heat, smoothing or wrinkling their surfaces in under a second after being stretched or electrically triggered. This can potentially make them invisible to infrared night vision tools or lets them modulate their IR emission temperatures.
"It goes from wrinkled and dull to smooth and shiny, essentially changing the way it reflects the heat," says researcher Alon Gorodetsky. Potential uses include better camouflage for troops and insulation for spacecraft, storage containers, emergency shelters, clinical care, and building heating and cooling systems.
Made of sandwiches of aluminum, plastic, and sticky tape, the material transforms from a wrinkled grey to a glossy surface when it is either pulled manually or biased with a voltage. Patents are pending.
“It was hard, especially the first phase when we were learning how to work with the sticky material,” says doctoral student Chengyi Xu. After trial-and-error processes involving thousands of attempts, he and postdoctoral scholar George Stiubianu finally saw the mirror-like coating change when they pulled it sideways.
The researchers say the material will be straightforward to manufacture.
1. Chengyi Xu, George T. Stiubianu, and Alon A. Gorodetsky, Science (2018); doi: 10.1126/science.aar5191.