A popular polymer can remember what shape it was in.
Nafion is a useful material that has been around since the 1960s, but don’t be surprised if you’ve never heard of it. It was first made by a chemist at DuPont, a company that makes chemicals, and it is a common ingredient in fuel cells. (Fuel cells, which are sometimes used to power satellites, produce energy from hydrogen.)
Now, a scientist in Michigan has shown that Nafion has another nifty purpose: It can “remember” three different shapes. If you were to twist some Nafion into, say, a donut shape, it would be able to form into a donut again later.
Don’t go quizzing your nearest Nafion just yet. Its memory isn’t of the usual kind: Nafion’s memory is based on temperature. Nafion is a synthetic polymer, which means it’s a manmade material of thousands of molecules linked together like a chain. Polymers come in many shapes and sizes — in fact, Silly Putty is a familiar polymer.
This image represents how a certain material would look if you could see the way its atoms get together. The green, blue, red and yellow circles are atoms lined up in long chains that create the polymer Nafion.