In many situations, we want to hold gases within a container or keep them out. Achieving this is harder than you may think though, as many materials are permeable to gas molecules, including many plastics. Researchers at Rice University, and in Hungary, Slovenia, and India though have managed to combine a polymer and graphene nanoribbons to make a nearly impermeable barrier.
Graphene is an atom-thick sheet of carbon that is capable of blocking gas molecules, but it is difficult to produce, so the researchers had to look elsewhere. In this case they went to graphene nanoribbons, which are actually made by unzipping carbon nanotubes. The nanoribbons are then solution cast into a polymer, where they disperse enough to mimic a full sheet of graphene. When the composite material, containing just 0.5% nanoribbons by weight, was used to separate a vacuum from a chamber full of nitrogen, the pressure did not change after 1000 seconds, and barely dropped over 18 hours.
Potentially this composite material could be used for preserving food, drinks, beer, and storing compressed natural gas for cars. As the 0.5% mixture also provided optimal strength for the polymer, that latter possibility could become quite real, as the polymer could be a lot lighter than an all metal tank.
Source: Rice University