Material that mimics squid skin is invisible to military NIR cameras

A team at the University of California Irvine, USA, led by Alon Gorodetsky has produced reflectin (a structural protein essential in the squid’s ability to change colour and reflect light) in common bacteria and used it to make thin, optically active films that mimic the skin of a squid. With the appropriate chemical stimuli, the films’ colouration and reflectance can shift back and forth, giving them a dynamic configurability that allows the films to disappear and reappear when visualised with an infrared camera.

Infrared detection equipment is employed extensively by military forces for night vision, navigation, surveillance and targeting. The novelty of this coating lies in its functionality within the NIR region, approximately between 700 nm and 1200 nm, which matches the standard imaging range of most infrared visualisation equipment. This region is not usually accessible to biologically derived reflective materials.

“Our approach is simple and compatible with a wide array of surfaces, potentially allowing many simple objects to acquire camouflage capabilities,” said Gorodetsky, whose work has possible applications in infrared stealth camouflage, energy-efficient reflective coatings and biologically inspired optics. This is just the first step in developing a material that will self-reconfigure in response to an external signal, he added. The researchers are currently formulating alternative, non-chemical strategies for triggering colouration changes in the reflectin coating.

“Our long-term goal is to create fabrics that can dynamically alter their texture and colour to adapt to their environments,” Gorodetsky said.

The work was published in Advanced Materials (doi: 10.1002/adma.201301472).