Nanotech has fashioned from graphene a one atom-thick membrane impermeable even to helium gas. From “World’s Thinnest Balloon Developed: Just One Atom Thick“:
Researchers in New York are reporting development of the world’s thinnest balloon, made of a single layer of graphite just one atom thick. This so-called graphene sealed microchamber is impermeable to even the tiniest airborne molecules, including helium.
It has a range of applications in sensors, filters, and imaging of materials at the atomic level.
Paul L. McEuen and colleagues note that membranes are fundamental components of a wide variety of physical, chemical and biological systems, found in everything from cellular compartments to mechanical pressure sensing. Graphene, a single layer of graphite, is the upper limit: A chemically stable and electrically conducting membrane just one atom thick. The researchers wanted to answer whether such an atomic membrane would be impermeable to gas molecules and easily incorporated into other devices.
Their data showed that graphene membranes were impermeable to even the smallest gas molecules. These results show that single atomic sheets can be integrated with microfabricated structures to create a new class of atomic scale membrane-based devices.
The research was published in Nano Letters (abstract)