Fans of Spider-Man know all about the strength of spider webs. It turns out, though, that spider-strings are good not only for jumping between buildings. According to new research, they are also fantastic conductors of heat. Who cares? Well, that means spider webs could become an important part of our electronics, among other human-made products.
Xinwei Wang, and two colleagues at Iowa State University, found that spider silk is a better conductor than aluminum, iron, and silicon, and transfers heat 800 times better than other organic tissues, and 1,000 times better than silkworm silk. Even better, conductivity improves even when you stretch the strings, in contrast to other materials.
Xinwei Wang, an associate professor of mechanical engineering, says he had an idea that spider silk could be a good conductor because of its strength, and perfect molecular structure. Wang ordered eight Nephila clavipes, or Golden Orbweavers, from California. Measuring about the size of a human hand, the spiders are non-poisonous, and often kept as pets. He put the creatures in a cage inside a greenhouse, and then waited for the silk to appear.
Wang says the silks could be used in several practical ways–notably to dissipate heat away from high-performance computer processors. “Spider silk has a very high conductivity that you can use for this type of electronics cooling,” he says. “It’s lightweight. It’s very flexible. And it’s easy to transfer the heat away from the CPU,” he says. Soon your computer may be filled with spider webs.
The difficulty is to mass-produce the spider silks. So, Wang says it’s more likely researchers will look to transfer spider genes to silk worms, to produce silk with spider strength. “You can genetically modify silkworm silk, and get something very close to spider silk, and you hope you will have properties as good as spider silk,” he says.
Wang, who goes by the name of “Spiderman” around campus, is now looking at whether other spider types–including black widows––produce silks with other useful properties. His team will announce its findings soon. “With different silks, the elasticity can be different, but they are very promising for thermal transport,” Wang says. “It’s very interesting to us.”