Self healing polymers have a micro-encapsulated healing agent that is embedded in a structural composite matrix. A crack ruptures the microcapsules, releasing the healing agent into the crack plane through capillary action. The healing agent contacts a catalyst, triggering polymerization that bonds the crack faces closed.

Polymerization of the healing agent is triggered by contact with the embedded catalyst, bonding the crack faces. The damage-induced triggering mechanism provides site-specific autonomic control of repair. An additional unique feature of the healing concept is the utilization of living polymerization (that is, having un-terminated chain-ends) catalysts, thus enabling multiple healing events. Fracture experiments yield more than 90% recovery in toughness.

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