The silk of the humble spider has some pretty impressive properties. It’s one of the sturdiest materials founsd in nature, stronger than steel and tougher than Kevlar. It can be stretched several times its length before it breaks. For these reasons, replicating spider silk in the lab has been a bit of an obsession among materials scientists for decades.
Now, researchers at the University of Cambridge have created a new material that mimics spider silk’s strength, stretchiness and energy-absorbing capacity. This material offers the possibility of improving on products from bike helmets to parachutes to bulletproof jackets to airplane wings. Perhaps its most impressive property? It’s 98 percent water.
The lab-made fibers are created from a material called a hydrogel, which is 98 percent water and 2 percent silica and cellulose, the latter two held together by cucurbiturils, molecules that serve as “handcuffs.” The silica and cellulose fibers can be pulled from the hydrogel. After 30 seconds or so, the water evaporates, leaving behind only the strong, stretchy thread.
The fibers are extremely strong – though not quite as strong as the strongest spider silks – and, significantly, they can be made at room temperature without chemical solvents. This means that if they can be produced at scale, they have an advantage over other synthetic fibers such as nylon, which require extremely high temperatures for spinning, making textile production one of the world’s dirtiest industries. The artificial spider silk is also completely biodegradable. And since it’s made from common, easily accessible materials – mainly water, silica and cellulose – it has the potential to be affordable.
Because the material can absorb so much energy, it could potentially be used as a protective fabric. “Spiders need that absorption capacity because when a bird or a fly hits their web, it needs to be able to absorb that, otherwise it’s going to break,” says Darshil Shah, an engineer at Cambridge’s Centre for Natural Material Innovation.
Other potential applications include sail cloth, parachute fabric, hot air balloon material, and bike or skateboard helmets. The material is biocompatible, which means it could be used inside the human body for things like stitches.
“Currently we make around a few tens of milligrams of these materials and then pull fibers from them,” Shay says, “but we want to try and do this at a much larger scale.”
To do so, the team is working on a robotic device to pull and spin fibers more quickly and at a larger scale than previously. They’ve had some success, Shah says, and continue to explore the process. “We’re still in the early stages of research,” he says.