This Hair-Thin Film Blocks More Than 99.9999999% of Radar-Band Electromagnetic Waves and Hides Heat From Infrared Cameras

Carbon nanotubes and MXene combine shielding, strength and thermal camouflage in a hair-thin film.

A new material barely thicker than kitchen cling film can block more than 99.9999999 percent of electromagnetic waves in frequencies used by radar and communications. Yet it is flexible, exceptionally strong and difficult to see with an infrared camera.

That unusual combination could make the film useful in military aircraft, drones and spacecraft, where engineers want to protect sensitive electronics without adding heavy metal shielding. It could also find its way into phones, wearable devices and future foldable electronics.

Researchers in South Korea created the film from two materials with very different strengths: carbon nanotube fibers, which are light and extraordinarily tough, and a sheet-like material called MXene, which conducts electricity well and gives off relatively little infrared radiation.

The result is just 17.5 micrometers thick — roughly one-fifth the thickness of a human hair — but can withstand pulling forces comparable to high-strength steel.

A brick wall too small to see

The problem the researchers faced was that neither material worked particularly well alone.

Carbon nanotube fibers are essentially threads made from microscopic tubes of carbon. They are light, flexible and strong, and electricity moves through them easily. But making those threads into a large, solid sheet is challenging in both lab and industrial settings. The fibers can slip past one another, weakening the material. They also radiate heat strongly enough to stand out to infrared cameras.

MXene has almost the opposite strengths and weaknesses. It can form thin conductive sheets and emits relatively little infrared radiation, making it attractive for thermal camouflage. But MXene films can be fragile and can deteriorate over time.

The engineering solution eventually came up when one of the South Korean researchers thought of bricklaying.

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They lined up the carbon nanotube fibers as the “bricks” and filled the spaces between them with MXene “mortar.” They first chemically treated the fibers so the MXene would stick to them more evenly. That stopped the fibers from sliding around and created an interconnected network through which electricity could flow.

“The key to this technology is combining nanomaterials with different characteristics like bricks and mortar, preserving the strengths of each material while compensating for their respective weaknesses,” Taehoon Kim of the Korea Institute of Materials Science, who led the research, said in the institute’s press release.

The finished material reached a tensile strength of 1.02 gigapascals, about twice that of a film made only from the nanotube fibers in the researchers’ tests. It also kept working after repeated bending and exposure to demanding environmental conditions, according to the study.

Hiding from more than one kind of detector

The electromagnetic shielding was particularly striking.

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Across radar and communication frequency bands, the film achieved around 90 decibels or more of shielding, which the researchers translate to blocking more than 99.9999999 percent of incoming electromagnetic waves. Tests covered frequencies used in radar as well as some emerging high-frequency 5G and 6G systems.

Important caveat time: the film’s extraordinary performance refers to electromagnetic shielding, not radar invisibility. It stopped radar-frequency waves from passing through the material, which could help protect sensitive electronics from interference, jamming or electromagnetic pulses. But conventional radar stealth requires reducing the signal reflected back toward a radar receiver, and the researchers did not test the film for that purpose.

At the same time, the MXene coating reduced how much infrared energy escaped from the surface. A thermal camera therefore sees a much weaker heat signal than it would from the carbon nanotubes alone. The researchers found that this effect continued from room temperature up to 300 degrees Celsius.

Scientists have been pursuing this combination for several years. In 2024, another team reported a 15-micrometer MXene and carbon-nanotube film that combined electromagnetic shielding with infrared camouflage. That material reached 72 decibels of shielding and a tensile strength of 77 megapascals. The new design reaches more than 90 decibels while being more than 10 times stronger, although the studies used somewhat different designs and tests.

For now, the film remains a laboratory material rather than something ready to wrap around a sixth-gen fighter jet. The team still needs to manufacture much larger sheets and show that they can survive years of real-world use.

“We expect this multifunctional material to find broad applications not only in future defense systems and aerospace technologies but also in addressing electromagnetic interference issues in next-generation communication devices and wearable electronics,” Kim said in the KIMS release.

The findings were reported in the journal Advanced Composites and Hybrid Materials.