A synthetic material developed by Danish scientists could someday allow a human to breathe underwater like the comic book character Aquaman, with no need for scuba tanks, the researchers say.
They report creating a synthetic crystal material so oxygen-hungry a spoonful can absorb all of the oxygen present in an average-size room.
It can also attract oxygen from water like a sponge, and the oxygen can then be released by exposing the material to a small amount of heat or to low pressure or a vacuum, the researchers at the University of Southern Denmark said.
The novel material is based on the element cobalt, and binds it within an organic molecule.
"Cobalt gives the new material precisely the molecular and electronic structure that enables it to absorb oxygen from its surroundings," university researcher Christine McKenzie said. "Small amounts of metals are essential for the absorption of oxygen, so actually it is not entirely surprising to see this effect in our new material."
The substance is able to absorb and hold oxygen to a concentration some 160 times greater than in air that surrounds us, which is 21 percent oxygen, the researchers report in the journal Chemical Science.
Although the possibility of legions of scuba-free Aquamen swimming the world's oceans may be some way off, the material suggests some more immediate possibilities, McKenzie says.
"This could be valuable for lung patients who today must carry heavy oxygen tanks with them," she says.
"When the substance is saturated with oxygen, it can be compared to an oxygen tank containing pure oxygen under pressure -- the difference is that this material can hold three times as much oxygen."
Different versions of the substance can absorb and release oxygen at different speeds, the researchers say, suggesting it could be used in devices intended to release and/or absorb oxygen for different purposes.
For example, they say, a facemask with different layers of versions of the material in a certain sequence could conceivable supply a person with oxygen directly from the air without resorting to high-pressure equipment or pumps.
Which takes the technology into Aquaman territory, a use McKenzie sees as entirely possible.
"Divers may one day be able to leave the oxygen tanks at home and instead get oxygen from this material as it 'filters' and concentrates oxygen from surrounding air or water," she says. "A few grains contain enough oxygen for one breath, and as the material can absorb oxygen from the water around the diver and supply the diver with it, the diver will not need to bring more than these few grains."