Scientists unveil shield thinner than hair

Shielding sounds simple — put a barrier between something fragile and something dangerous. But modern radiation shielding is usually a mess of tradeoffs. One layer handles electromagnetic interference. Another handles neutrons. Then the whole thing gets thick, heavy, rigid, and awkward to use. The news here is that a team at the Korea Institute of Science and Technology, led by Joo Yong-ho, says it built a single film that does both jobs while staying thinner than a human hair. ### What did they actually make? The material is a composite built from two nanotubes with very different talents. Single-walled carbon nanotubes handle electromagnetic waves because they conduct well and can absorb or reflect that energy. Boron nitride nanotubes handle neutrons because boron is good at capturing them. The team combined both inside a stretchable PDMS polymer, turning the result into a flexible film and also a printable ink for more complex shapes. ### Why is doing both in one layer hard? Because these hazards are not the same problem. Electromagnetic interference is basically stray energy that can scramble electronics. Neutron radiation is particle damage — bad for both devices and living tissue. Materials that work well for one often are not the best answer for the other, so engineers usually stack separate shields. That adds mass and thickness, which is especially painful in spacecraft and wearable gear. ### What is the key trick? Turns out the interesting part is not just the ingredient list. The nanotubes form a kind of shell-like structure, with one wrapping around the other. That helps the film create a continuous network for electromagnetic shielding while keeping boron-rich regions available to catch neutrons. Basically, instead of forcing two incompatible materials into separate layers, the team got them to self-organize into one cooperative structure. ### How good is the shielding? The headline numbers are strong. At a thickness thinner than a human hair, the film blocked 99.999% of electromagnetic waves and reduced neutrons by about 72%. Those are lab results, not a finished product spec sheet, but they are the reason this work is getting attention. Thin shields usually make you give something up. Here the pitch is that you keep performance while shedding bulk. ### Why does stretchiness matter? A rigid shield is fine if you are lining a box. It is much less useful if you need to wrap curved electronics, fit odd spacecraft geometries, or build wearable protection. The PDMS matrix makes the composite rubbery, and the team says it can be processed with direct ink writing, including freestanding honeycomb lattices. That opens the door to shields shaped for the object instead of forcing the object to fit the shield. ### Where could this show up first? Space is the obvious pitch because every gram matters and spacecraft carry sensitive electronics. But the same logic applies to semiconductor tools, nuclear settings, and some medical devices. The catch is that “could be used” is not the same as “ready to deploy.” Real adoption means durability testing, manufacturing at scale, and proving performance under the exact radiation environments those systems face. ### So what is the bottom line? This is a materials advance, not a finished spacesuit. But it is a real one. A single, ultrathin, stretchable film that handles both electromagnetic waves and neutrons attacks one of the oldest shielding headaches — too many layers, too much weight, too little flexibility. If the lab results hold up in real hardware, the biggest win will be simpler protection in places where mass and shape matter most.