MIT researchers have created a new type of polymer film that is so tightly sealed it can stop even the smallest gas molecules from passing through.
This breakthrough could make it possible to protect solar panels, electronics, buildings, vehicles, and even packaged food and medicines from damage caused by air and moisture.
The new material is extremely lightweight—only a few nanometers thick—yet it forms a barrier as strong and impermeable as graphene, one of the most famous materials in science.
Typically, polymers such as plastics allow small amounts of gas to sneak through because their long, spaghetti-like molecular chains leave tiny gaps.
But the new polymer behaves very differently. It forms flat, disk-like molecules that layer tightly on top of each other. These layers are held firmly together by hydrogen bonds, leaving no space for gas molecules to slip through.
“It’s a surprising material,” said Michael Strano, an MIT chemical engineering professor and senior author of the study, which appears in Nature.
“It looks nothing like a perfect crystal, but it acts like one.” The structure is so airtight that even highly penetrating gases like helium and nitrogen cannot pass through it in the laboratory.
This new film is based on a material Strano’s team first introduced in 2022, called 2DPA-1. It is a two-dimensional polyaramid—a type of polymer that forms sheet-like layers rather than tangled chains.
The material is incredibly strong, stronger than steel while being much lighter, and now researchers have shown it is also remarkably impermeable.
The impermeability was discovered almost by accident. The team created tiny polymer “bubbles” filled with gas to measure how quickly the gas escaped—a standard test for polymer films. To their surprise, the bubbles never deflated.
Bubbles made in 2021 were still fully inflated years later. This prompted researchers to run long, careful experiments showing that nitrogen and other gases simply could not pass through the polymer.
Tests revealed that the film blocks helium, argon, oxygen, methane, and sulfur hexafluoride at levels at least 10,000 times better than any conventional polymer. Its performance is nearly equal to graphene, which is considered perfectly impermeable—but graphene is difficult and expensive to apply to large surfaces.
That is where 2DPA-1 stands out. It can be made in large quantities and easily applied as a coating. Just a 60-nanometer layer—about 1,000 times thinner than a human hair—extended the life of perovskite solar-cell material by several weeks. With a thicker coating, the protection could last much longer. That kind of durability could help solar panels resist corrosion and extend their usable life.
Beyond solar cells, the new polymer could protect bridges, buildings, vehicles, ships, and any structure exposed to air, moisture, and harsh conditions. It could also keep food and medicines fresh for longer by preventing oxygen from seeping in.
The team also demonstrated a completely different application: making tiny vibrating “resonators,” which help smartphones tune in to communication signals. Because the polymer is strong and impermeable, it can be used to create the first polymer-based resonators at nanoscale sizes.
As Strano explains, “This material could change the way we protect infrastructure and build future electronics.” The work was supported by the U.S. Department of Energy and the National Science Foundation and conducted partly at the MIT.nano facilities.
