MIT Develops New Wet Suits Inspired by Otter Pelts
Researchers from the Massachusetts Institute of Technology have developed a new type of wetsuit inspired by the mechanism behind otters and beavers insulating pelts.
According to a study published in the journal Physical Review Fluids, the ability of otters and beavers to withstand cold waters is made possible by its fur. These semi-aquatic mammals have two types of furs, the long thin "guard" hairs and the shorter, denser "underfur." The guard hairs acts as shield that protect the underfur, preventing water from penetrating. By doing so, warm air is trapped against the animal's skin.
"Air is about 20 times less thermally conductive than water, which means it is an excellent insulator," explained Alice Nasto, a graduate student at MIT and lead author of the study, in a report from Christian Science Monitor. "When a layer of air is trapped between skin and cold water, it provides protection against the cold."
To test out if the mechanism behind otters insulating ability could be applied in wetsuits, the researchers fabricated precise, fur-like surface of various dimensions and plunged them into silicone oil.
The researchers observed a clear boundary between liquid and air within the hairs as they push the surface down. The air formed a thicker layer in hairs closer to the surface, but progressively thinned out as the surface sank further.
Additionally, the researchers also found that the surface with denser furs retained thicker air layer within its hairs when submerged at higher speeds.
"Basically we found that the weight of the water is pushing air in, but the viscosity of the liquid is resisting flow (through the tubes)," said Anette (Peko) Hosoi, a professor of mechanical engineering and associate head of the department at MIT, in a statement. "The water sticks to these hairs, which prevents water from penetrating all the way to their base."
With their experiments, the researchers noted that the spacing of individual hairs and the speed they were submerged played a large role in determining how much air a surface could trap.