It doesn’t take much liquid to fix a single crack, and the internal channels can store relatively large volumes of fluid. So when the next cut or scratch comes along, the process repeats itself. “If the material is damaged in the same spot, you can keep re-healing the same crack over and over again,” Sottos says. As Sottos has refined her technique, she has been able to design plastics that can repair more than 50 cracks in a row. The liquids can also be replenished as they’re depleted. “The other nice thing about vascular networks is that you can recharge them,” Sottos says. “Let’s say your material’s going to sit around for 20 years - in a vascular system you can replace your healing agent kind of the same way you replace your oil.”
So far, Sottos has used her vascular method to create self-healing hard plastics and foams. She has also developed plastic that actively pumps healing fluid to the site of an injury—much as our own circulatory systems do—rather than allowing it to passively ooze into a wound. These self-healing polymers could be used to extend the lives of products large and small, including airplanes, wind turbines, and consumer electronics.
She’s also shown that microvascular networks can be used for more than just healing. In a paper published in 2011, Sottos demonstrated that engineers could reduce a material’s temperature by circulating water through tiny, sub-surface channels. The concept could eventually be used to design computer chips and other electronics—which are susceptible to overheating—that can regulate their own temperatures.
But whatever the eventual application, Sottos is driven by the idea of learning from nature.
“We want to impart this concept of autonomy to a synthetic material—self-heal, self-cool, self-sense, do all these things that we take for granted in natural systems.”