'Artificial blubber' t0 protect divers in icy water

Scientists have created wetsuits with 'artificial blubber' that can keep deep sea divers warm in icy cold water.

When rescue teams are diving under ice-covered rivers or ponds, the survival time even in the best wetsuits is very limited - as little as tens of minutes, and the experience can be extremely painful at best.

Researchers from Massachusetts Institute of Technology (MIT) and George Mason University in the US developed a simple treatment that can improve the survival time for a conventional wetsuit by a factor of three.

The process works by simply placing the standard neoprene wetsuit inside a pressure tank autoclave no bigger than a beer keg, filled with a heavy inert gas, for about a day.

The treatment then lasts for about 20 hours, far longer than anyone would spend on a dive, said Jacopo Buongiorno, professor at MIT.

The process could also be done in advance, with the wetsuit placed in a sealed bag to be opened just before use, he said.

Researchers looked at the different strategies that various animals use to survive in these frigid waters, and found three types: air pockets trapped in fur or feathers, as with otters and penguins; internally generated heat, as with some animals and fish; or a layer of insulating material that greatly slows heat loss from the body, as with seals' and whales' blubber.

After simulations and lab tests, they ended up with a combination of two of these - a blubber-like insulating material that also makes use of trapped pockets of gas, although in this case the gas is not air but a heavy inert gas, namely xenon or krypton.

The material that has become standard for wetsuits is neoprene, an inexpensive material that is a mix of synthetic rubber materials processed into a kind of foam, producing a closed-cell structure similar to styrofoam.

Trapped within that structure, occupying more than two-thirds of the volume and accounting for half of the heat that gets transferred through it, are pockets of air.

Researchers found that if the trapped air is replaced with xenon or krypton, the material's insulating properties increase dramatically. The result is a material with the lowest heat transfer of any wetsuit ever made.

"We set a world record for the world's lowest thermal conductivity wetsuit. It's like wearing a coat of air," said Michael Strano, a professor at MIT.

They found this could improve survivability in water colder than 10 degrees Celsius, raising it from less than one hour to two or three hours.

The result could be a boon not just to those in the most extreme environments, but to anyone who uses wetsuits in cold waters, including swimmers, athletes, and surfers, as well as professional divers of all kinds.