“Nanostitches” enable lighter and tougher composite materials

Researchers from the Massachusetts Institute of Technology, Universitat de Girona in Spain, and Universidade do Porto in Portugal have shown that they can prevent cracks from spreading between layers in a composite material by depositing chemically grown forests of carbon nanotubes between the composite layers. The tiny, densely packed fibers grip and hold the layers together, like ultrastrong Velcro, preventing the layers from peeling or shearing apart. In experiments with an advanced composite, known as a thin-ply carbon fiber laminate, the team showed that layers bonded that way improved the material's resistance to cracks by up to 60% compared with composites with conventional polymers.