Internal damage in fiber-reinforced composites, materials used in structures of modern airplanes and automobiles, is difficult to detect and nearly impossible to repair by conventional methods. A small, internal crack can quickly develop into irreversible damage from delamination, a process in which the layers separate. This remains one of the most significant factors limiting more widespread use of composite materials.
However, fiber-composite materials can now heal autonomously through a new self-healing system, developed by researchers in the Beckman Institute's Autonomous Materials Systems (AMS) Group at the University of Illinois at Urbana-Champaign, led by professors Nancy Sottos, Scott White, and Jeff Moore.
Sottos, White, Moore, and their team created 3D vascular networks—patterns of microchannels filled with healing chemistries—that thread through a fiber-reinforced composite. When damage occurs, the networks within the material break apart and allow the healing chemistries to mix and polymerize, autonomously healing the material, over multiple cycles. These results were detailed in a paper titled "Continuous self-healing life cycle in vascularized structural composites," published in Advanced Materials.
"This is the first demonstration of repeated healing in a fiber-reinforced composite system," said Scott White, aerospace engineering professor and co-corresponding author. "Self-healing has been done before in polymers with different techniques and networks, but they couldn't be translated to fiber-reinforced composites. The missing link was the development of the vascularization technique."
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