Gas marbles

MARBLES of encapsulated gas that endure tenfold changes in pressure could be used to design new aerated materials or imprison valuable gases, according to French researchers.

Recently, a lot of research has been undertaken on “liquid marbles”, which are liquid drops coated with micro- or nanoscale hydrophobic particles. They have unusual physical and chemical properties, and can be used in several applications, including microreactors and water storage.

Now, a team of researchers from Université Paris-Est have described a new alternative capable of encapsulating gases, that they call the “gas marble”.

The team created the marbles by dipping a solid horizontal frame into a soap solution. The solution contains SDS as a surfactant, with a raft of floating polystyrene beads. On removing the frame, a particulate film was detached by gravity and then closed over itself to form a bubble. The beads within the bubble were held together as a group by a liquid meniscus, due to surface tension.

While characterising the marbles, the researchers discovered that they could insert a syringe into the marbles without popping them, allowing for loading or removal of gas. They found that marbles did not change in size with loading or gas removal. Tests also showed that they could withstand pressures up to 10 times greater or lower than their initial formation pressure at formation before bursting.

The team believe the gas marbles could be used to stabilise foams and store gases.

They are currently planning experiments designed to better understand the permeability of the marbles, to determine which gases they could potentially hold. They also intend to investigate how long the marbles will last under various conditions before the water in the film holding them together evaporates.

Physical Review Letters: http://doi.org/b8d7