Synthetic rubbers are elastic, which means they return to their original shape after having been bent or stretched. However, the force these synthetics can take is limited. On the other hand, there are extremely strong synthetics, but those aren’t elastic. Right now, for rubber tires that issue is being tackled by adding soot particles, but that’s harmful to the environment, among other downsides.

For a while now, experiments involving the interweaving of several polymer types with distinct qualities, where the one type provides elasticity and another polymer a sturdy network that strengthens the material. Sijbesma’s contribution to the article that was published in Science mostly involves the implementation of crosslinkers: molecules that connect polymer chains. The crosslinker that’s been used is called BADOBA and emits a tiny flash of light if it breaks. It’s a way for the scientist to see where the material breaks under mechanical loads.

“The light that’s emitted shows us exactly where the chains break”, Sijbesma explains. “In multiple networks breaks occur in a much larger area than in a single network. And that’s the reason it takes a lot more energy to break the material.” And it’s why the material is stronger by definition. Still, in time more and more of the chains in the stiff component will break, so the material will show signs of aging eventually. With the help of the crosslinkers, it’s possible to search for materials with the right qualities for particular uses, including car tires, elastic gloves, or dampers.