The Navy SEALs are getting an apparel upgrade. And it's inspired by actual seals.
Members of the elite military special operations force told MIT researchers they needed a way to survive in frigid water longer without losing any mobility. After two years, the researchers came up with a solution: a wetsuit treatment that increases survival time by a factor of three without adding any bulkiness.
They published a study on this material on Monday in the journal RSC Advances.
In the wild, animals typically have one of three natural defenses against the cold. Some, such as great white sharks, generate heat internally. Others, like penguins, have trapped pockets of air in their fur or feathers that act as a buffer from the cold. Finally, some critters are covered with a layer of natural insulation, such as the blubber that protects seals from the cold.
The MIT team combined the latter two defenses to create an artificial blubber that met the Navy SEALs' needs.
The material used to construct most standard wetsuits is neoprene, a synthetic rubber that resembles a dense foam with lots of little air pockets. These air pockets help slow the transfer of heat from your body into the colder water surrounding you.
The MIT researchers realized that replacing the air in the neoprene holes with a heavy inert gas, specifically xenon or krypton, slowed the transfer even more. Instead of surviving less than one hour in 10 degree Celsius (50 degree Fahrenheit) water, a person could survive two to three hours.
“We set a world record for the world’s lowest thermal conductivity garment,” study author Michael Strano said in a news release. “It’s like wearing a coat of air.”
To make the switch from air to xenon or krypton, all the researchers had to do was place a standard neoprene wetsuit into a sealed container about the size of a beer keg. They pumped the container full of the heavy, inert gas of their choosing until the pressure within it reached 20 psi (pound-force per square inch).
The wetsuit retained its greater insulating properties for 20 hours after treatment. If the wetsuit was placed in a sealed bag right after the gas transfer, that 20 hour countdown wouldn't start until someone removed it.
This artificial blubber treatment isn't only good for longer stints in frigid water. Wetsuit users told the MIT team that they often struggled to move around in their wetsuits, and also to get in and out of them. MIT's insulation method could produce wetsuits that are half as thick as traditional ones, but with the same amount of thermal insulation, according to study author Jeffrey Moran.
This feature could be particularly useful for the Navy SEALs, athletes, or people involved in rescue missions, such as those attempting to save people who've fallen through ice.
Next, the MIT team plans to look into ways to permanently inject xenon or krypton into the neoprene, perhaps by adding another layer to the material. For now, their artificial blubber should still provide the Navy SEALs with plenty of time for any planned operations — after all, even actual seals don't spend 20 hours straight in frigid water.