Here’s what you’ll learn when you read this story:

• Since its invention, Kevlar has saved thousands of lives thanks to the synthetic polymer being both incredibly lightweight and incredibly strong.
• However, Kevlar is far from the last word on ballistic protection, and a new study reports a material woven with carbon nanotubes that’s both three times stronger than Kevlar and only 1.8 millimeters thick.
• Scientists created this material by combing carbon nanotubes with aramid polymers (which are also used in Kevlar) and aligning them in just the right way to protect against slippage under immense impact.

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Since the invention of Kevlar in the 1960s, this extra-strong synthetic fiber woven into rugged body armor has saved the lives of at least 3,000 police officers, according to the National Institute of Justice. In many regards, it’s a wonder of materials science, and while Kevlar’s performance and manufacture has improved over time, scientists have developed a handful of candidates that could be Kevlar’s next-generation replacement—molecular “chainmail,” another polymer-based material called Dyneema, evenspider silk.

Now, scientists may have developed another challenger to the Kevlar crown—a lightweight material that’s three times stronger than Kevlar, only 1.8 millimeters thick, and laced with carbon nanotubes (CNTs).

You’ve likely heard of these nanoscale carbon tubes—they’re known for both exceptional thermal conductivity (which is why scientists are experimenting with using them to replace silicon in computer chips) and incredibly high tensile strength. The latter of those traits was of particular interest to Jin Zhang from the University of Peking, who spent six years developing materials that surpass Kevlar.

“Ultra-high dynamic strength and toughness are crucial for fibrous materials in impact-protective applications. These include bullet-proofing armors, vehicles, and aircraft,” Zhang told New Scientist. “Our new fibre significantly surpasses all reported macroscopic high-performance polymer fibers. Our fabric outperforms Kevlar entirely.”

These aren’t just fighting words, as can be seen in a study introducing the material to the world published in the journal Matter. In the study, Zhang and his colleagues describe how they aligned CNTs with an aramid polymer—a synthetic material also known for its immense strength and heat resistance (and which is also used in the production of Kevlar). Typically, when you try to make these polymers, they become more brittle. But that’s where the CNTs come in.

The carbon nanotubes—technically called treated long single-walled nanotubes (tl-SWNTs)—are extremely strong and are each as thin as a human hair. Researchers first forced the aramid chains and CNTs to be parallel by making aramid chains more flexible and then stretching them to the proper alignment. This nanoscale organization made it possible for the components to essentially lock into place and avoid slipping past each other, which allowed the material to absorb more energy (a.k.a. higher impacts) without failing.

After a series of ballistic tests, Zhang and his team confirmed that their carbon nanotube-reinforced material could absorb 706.1 megajoules per cubic meter, which they say doubles the current record.

“The trade-off between strength and toughness is a persistent challenge in materials science,” the authors wrote. “This work provides a fresh understanding and a feasible route for utilizing the intrinsic mechanical performance of polymer chains at the macroscale.”

Synthetic polymers like Kevlar and Dyneema represent the highest highs that humanity has reached on the innovative slope of ballistic protection, but studies like this one show that there’s still a ways to go before we reach the true pinnacle.

Darren lives in Portland, has a cat, and writes/edits about sci-fi and how our world works. You can find his previous stuff at Gizmodo and Paste if you look hard enough.