A new wetsuit material from MIT traps pockets of air in a fur-like pelt, keeping the wearer warm in the water. It works just like a beaver's fur coat, which was the rubbery material's inspiration.
The results of the research have been published in a new paper, which details the principals behind the fur of small aquatic mammals like beavers. These animals aren't big enough to carry a thick layer of blubber, so they need to keep warm in other ways. They do this by having a specialized kind of fur that traps air, insulating them in cold water. This kind of fur is much lighter and easier to wear than a thick blubber or neoprene suit, making it perfect as a wetsuit replacement. It's particularly suitable for surfers, who are constantly moving between water and air, just like a beaver.
The main factors that affect the faux-fur's ability to trap water bubbles are the spacing between the hairs and the speed at which they are plunged into the water, which were fine-tuned during research simply by casting a whole lot of different-sized furs from laser-cut molds, dipping them into water at different speeds, and measuring the bubbles that formed in them using video. "We can control the length, spacing, and arrangement of hairs, which allows us to design textures to match certain dive speeds and maximize the wetsuit's dry region," MIT professor Anette Hosoi said in a statement.
A regular wetsuit works by trapping a layer of water between the suit and the wearer's skin, which then warms up and keeps the wearer from freezing. Beaver fur, the researchers found, has two layers. The outer "guard" fur, keeps the water away from the short, dense "underfur," which traps warm air against the skin. Imagine that instead of getting wet when plunging into the cold ocean, you could stay dry, only without the bulk of a sealed drysuit, or even of a heavy wetsuit. Further, the water is easily shed when leaving the sea, making it lighter still.
The breakthrough in the MIT research, science-wise, are the equations which allow us to know exactly how much air will be trapped by a given fur density. That's good not only for fine-tuning wetsuit designs, but also for making materials that don't trap air. For instance, when a surface is dipped in a polymer in order to coat it with a protective layer, you want to avoid air bubbles entirely.
So what might a furry beaver suit look like? "You could make a very hairy wetsuit that looks like Cookie Monster and it would probably trap air," says Hosoi, "but that's probably not the best way to go about it."
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