University of Illinois researchers said the repair process involves solvent-filled microcapsules embedded in an epoxy matrix. The tiny microcapsules rupture when a crack forms in the plastic. Designed to mimic the human body's ability to repair wounds, the microcapsules release a healing agent into the crack. Then, through chemical and physical processes, the plastic material is restored to its undamaged state.

"While our previous solvent worked well for healing, it was also toxic," said Professor Scott White. "Our new solvent is both non-toxic and less expensive."

He noted the previous solvent allowed the epoxy resins to achieve 82 percent healing efficiency. But combining a non-toxic food additive (ethyl phenylactate) and an unreacted epoxy monomer in the microcapsules produced 100 percent healing efficiency.

"This work helps move self-healing materials from the lab and into everyday applications," research assistant Benjamin Blaiszik said.

The study that included research assistant Mary Caruso and Professors Nancy Sottos and Jeffrey Moore was reported in the journal Advanced Functional Materials.