Phase-Change Camouflage Hides Its Wearer From Thermal Cameras, PIR Sensors Whatever the Weather

Researchers from the University of California San Diego and National University of Singapore have developed an adaptive form of camouflage which successfully masks the wearer from thermal cameras and passive infrared sensors — regardless of environmental temperature.

Thermal sensors, in the form of simple PIR motion sensors all the way through to high-resolution thermal cameras, are popular for security applications: They don't need ambient light to work, they're capable of detecting a person through fog, smoke, and other atmospheric conditions, and are immune to traditional camouflage techniques. They're not, however, immune to a new phase-change camouflage system which is capable of masking the wearer's heat signature even when the ambient temperature changes.

Described by its creators as being in the "proof-of-concept" stage of development, the thermal camouflage works using a phase-change material similar in composition to wax: Melting at the same temperature as emitted by human skin, the material solidifies if the outside temperature is higher and melts if the outside temperature is lower. The result: To the camera, the material appears to be exactly the same temperature as the environment around it — and thus blends in perfectly.

The prototype device is made using the phase-change material and thermoelectric alloys sandwiched between elastomer sheets; a battery provides power under the control of a wirelessly-connected base board. Unfortunately, all that comes at a cost: Scaling up the compact wrist-worn prototype to jacket size would result in a coat weighing an impressive 4.5lbs and capable of running for only an hour — leading the team to seek lighter and thinner materials.

The team's paper has been published in the journal Advanced Functional Materials under a closed-access licence.