Researchers have shown material benefits to randomly arranged carbon atoms.
Carbon has become one of our most important engineering materials. Carbon fiber for example, needs no introduction. By combining light weight with steel-like strength, carbon fiber can today be found in cars, aircraft, and all manner of other devices and structures. Carbon nanotubes, graphene, and other configurations of the element will likely change engineering even more in the future. Carbon-based materials like carbon fiber are made by baking naturally occurring hydrocarbons at high temperature. However, one problem has been in determining whether chaotically ordered carbon atoms made for stronger or weaker materials, and this in turn, has made it difficult to assess what the ideal baking temperature should be.
Now, scientists have made a breakthrough. MIT researchers have reported to the journal Carbon that fewer, more randomly ordered carbon atoms make for lighter and stronger materials. They have found a link that directly relates the random ordering of the atoms to the density and strength of a graphite-like material called SU-8, that they built in a laboratory. SU-8 is commonly used in the electronics industry. By comparing different baking temperatures, the researchers were also able to find a sweet spot of 1,000 degrees Celsius.
“These materials we’re working with, which are commonly found in SU-8 and other hydrocarbons that can be hardened using ultraviolet [UV] light, are really promising for making strong and light lattices of beams and struts on the nanoscale, which only recently became possible due to advances in 3-D printing,” says MIT postdoc Itai Stein. “But up to now, nobody really knew what happens when you’re changing the manufacturing temperature, that is, how the structure affects the properties. There was a lot of work on structure and a lot of work on properties, but there was no connection between the two. … We hope that our study will help to shed some light on the governing physical mechanisms that are at play.”