Now, composite materials that can self-heal repeatedly

Researchers have created a 3D vascular system that allows for high-performance composite materials such as fiberglass to heal autonomously, and repeatedly.

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 created 3D vascular networks-patterns of microchannels filled with healing chemistries-that thread through a fiber-reinforced composite.

White, aerospace engineering professor and co-corresponding author, said this is the first demonstration of repeated healing in a fiber-reinforced composite system.

He said 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.

The vasculature within the system integrates dual networks that are isolated from one other. Two liquid healing agents (an epoxy resin and hardener) are sequestered in two different microchannel networks.

Fiber-composite laminates are constructed by weaving and stacking multiple layers of reinforcing fabric, which are then co-infused with a binding polymer resin. Using that same process, the researchers stitched in a sort of fishing line, made from a bio-friendly polymer and coined "sacrificial fiber," within the composite. Once the composite was fabricated, the entire system was heated to melt and evaporate the sacrificial fibers, leaving behind hollow microchannels, which became the vasculature for the self-healing system.

The results have been published in the journal Advanced Materials.