What if a piece of armour not only withstood the sharpest attacks from enemies but also flexibly responded to any challenge, light yet powerful, like a finely crafted "chainmail" tightly wrapped around the body? Researchers at an American university have recently created an entirely new material whose structure resembles a finely woven chainmail- layered and interlaced, incredibly strong. This new type of two-dimensional mechanical interlocking material (MIM) is, on a microscopic level, akin to a "molecular chainmail", offering unprecedented protective performance.

When you think of "chainmail", you might imagine the shiny armour worn by knights in ancient times. This armour is made up of metal rings linked together, tightly interlocking, not only sturdy and durable but also flexible enough to adapt to various complex combat situations. Professor Fraser Stoddart proposed a similar concept a long time ago: he dreamed of connecting molecules like rings to enhance the mechanical properties of polymers. Today, the research team at Northwestern University has finally overcome this challenge and successfully developed a material with a very high microscopic mechanical key density, as strong and flexible as chainmail.

Unlike many other technological breakthroughs, this innovation didn't come from a team that had been dedicated to researching it for years but rather emerged from a failed experiment. Originally, the researchers were trying to use a new crystal growth method to make polymers when they unexpectedly discovered a uniquely shaped monomer that resembled the letter "X". In this material, there are more than a trillion molecular rings interlocked within one square centimetre, forming an intricate "network" structure. Each molecule acts like a "lock ring" interwoven with one another. This unique structure allows it to quickly change shape when impacted. This means it has dual performance: when gently pulled, it's as soft as silk, offering almost no resistance; but when subjected to a strong impact, it can quickly harden, like a solid piece of metal. This is exactly the characteristic that bulletproof vests have been dreaming of - lightweight yet able to provide powerful protection at critical moments.

Wearing an ultra-light bulletproof vest under the scorching sun, you feel almost no burden. But as soon as you enter a tense situation, it instantly turns into an impenetrable wall, blocking all impacts. This is the magic of this new 2D mechanical interlocking material, like a magical "invisible shield" for your body. Let's first take a look at traditional bulletproof vests. Imagine wearing a suit made of 15 to 30 layers of Kevlar fibres, like a puzzle where each piece serves a protective function. However, wearing such a bulletproof vest still greatly restricts your movements not only is it heavy, but its flexibility is poor as if several layers of heavy armour have been strapped onto you, making your movements awkward. While protection is strong, the cost is high. However, with the addition of 2D MIM material, the situation changes dramatically, This material, like a magical "molecular chainmail", completely lightens the structure of traditional bulletproof vests, as though you're wearing an ultra-thin "invisible armour". Although its thickness and weight are greatly reduced, it can instantly become incredibly hard at crucial moments, almost like a "Transformers" of the protective world.

In the future, bulletproof vests will not only be as light as a layer of thin gauze but also be able to intelligently adjust hardness like a protective shield, providing wearers with unparalleled comfort and protection. This is not just about making bulletproof vests lighter, it's a "bulletproof revolution". For military and police personnel, this material means they will have more efficient and comfortable protective gear. For athletes and construction workers, this material can also become their "invisible shield", helping them withstand the impacts of extreme sports and protecting them from dangers they might encounter at work. It's like putting the human body into a "future battle suit" that's both light and strong. Whether on the battlefield or in daily life, it will become our invisible guardian, always ready to face any external challenges.

（Writer：Matti）