MIT engineers turned to an unlikely source in their efforts to keep surfers warm.
Culling inspiration from aquatic mammals, including beavers and sea otters, the engineers fabricated fur-like rubbery pelts and used them to help identify a mechanism that will trap air between individual hairs when they are submerged into liquid.
The experiment’s results were published in science journal Physical Review Fluids and they provide a detailed analysis of mammal’s insulation abilities in oceans. It is possible that these results will be used by wetsuit manufacturers in the future.
“We are particularly interested in wetsuits for surfing, where the athlete moves frequently between air and water environments,” said Anette (Peko) Hosoi, professor of mechanical engineering and associate head of the department at MIT. “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.”
Original research for the experiment was inspired by a 2015 trip to Taiwan. Hosoi, who also leads MIT’s sports technology and education program, brought a group of students to Taiwan to speak with sporting goods makers about new technologies, including wetsuit manufacturer Sheico Group.
“They are interested in sustainability and asked us, ‘Is there a bioinspired solution for wetsuits?’” Hosoi said. “Surfers, who go in and out of the water, want to be nimble and shed water as quickly as possible when out of the water, but retain the thermal management properties to stay warm when they are submerged.”
After returning to the U.S., the MIT engineers group developed a plan to fabricate fur-like surfaces, submerge them in liquid at various speeds and utilize video imaging to measure the fur’s trapped air during dives.
For the experiment, each fur-like surface was mounted to a motorized stage and plunged into silicone oil. Researches observed a clear boundary between air and liquid. Out of all fur-like surfaces, those with denser fur retained the thickest layer of air within their hairs.
“We have now quantified the design space and can say, ‘If you have this kind of hair density and length and are diving at these speeds, these designs will trap air, and these will not,” Hosoi said. “Which is the information you need if you’re going to design a wetsuit.”