A team of researchers from Cambridge-based Massachusetts Institute of Technology (MIT) and visiting scientists from France took inspiration from beavers, a semi-aquatic rodent, to derive a mathematical model that could be used to develop swimsuits and functional coating processes.
Beavers keep themselves dry and warm with the help of fur arranged in two forms with “guard hairs” repelling water and preventing its penetration to the under layer and the skin. The team is working to understand the engineering mechanism behind this natural process in beavers.
The research grew out of an interaction with an international wetsuit maker, Sheico Group. Anette Hosoi, professor of Mechanical Engineering at MIT, led a team of students to Taiwan and, while interacting with Sheico Group, was asked about using biomimetic approaches to find solutions to problems in developing future swimsuits.
Graduate student Alice Nasto fabricated the beaver fur structure using polydimethysiloxane. These fabricated hair structures were plunged into silicone oil so that video images of trapped air can be obtained clearly. This experiment showed that spacing between hairs and speed of plunging played important roles in determining the amount of air trapped. This led to a mathematical model, which can predict the air layers around fur and hair.
According to Hosoi, this model will enable designers to know if the fur structure they are designing will trap air or not. Jose Bico, based in Paris, France, states that understanding the air-trapping mechanism is also important in industrial coating applications, such as dip coating.
Biomimetic and wearable technologies have potential, but their practical applicability and economics aspects need careful study to make commercially successful products.
Seshadri Ramkumar is professor of technical textiles, Texas Tech University. For more, see “Biomimetics and biotextiles” by Dr. Ramkumar.