Working with the MER Corporation and using the corporation's CVD reactor, the team added a polymer to the nanotubes to bind them together, and then spun the resulting material into yarns. Then they tested the strength and failure rates of the material using in-situ SEM testing, which uses a powerful microscope to observe the deformation of materials under a scanning electron beam. This technology, which has only been available in the past few years, allows researchers to have extremely high resolution images of materials as they deform and fail and allows researchers to study materials on several different scales. They can examine individual bundles of nanotubes and the fiber as a whole.
"We learned on multiple scales how this material functions," said Tobin Filleter, a postdoctoral researcher in Espinosa's group. "We're going to need to understand how molecules function at these nanometer scales to engineer stronger and tougher fibers in the future."
The result is a material that is tougher than Kevlar meaning it has a higher ability to absorb energy without breaking. But Kevlar is still stronger meaning it has a higher resistance to failure. Next, researchers hope to continue to study how to engineer the interactions between carbon nanotube bundles and between the nanotubes within the bundle itself.
"Carbon nanotubes, the nanoscale building blocks of the developed yarns, are still 50 times stronger than the material we created," said Mohammad Naraghi, a postdoctoral researcher in Espinosa's group. "If we can better engineer the interactions between bundles, we can make the material stronger."
The group is currently looking at techniques like covalent
|Contact: Kyle Delaney|