Scientists have discovered plastic composites that mimic the self-healing abilities of living beings.
Researchers at the University of Illinois at Urbana-Champaign created epoxy composites that can repair deep, hidden, small cracks in parts made of the composites. Such self-healing materials could solve problems in industries ranging from aerospace to electronics.
Boeing Co. and Motorola Inc. are among the funders of the UI project. Aircraft firms extensively use thermoset composites and electronics companies rely on such materials for high-density circuits. The materials often are brittle.
The scientists created an epoxy composite that contains microspheres of dicyclopentadiene monomer. When a crack starts, it tends to impinge on a microsphere, breaking it open. The DCPD monomer polymerizes into a tough polymer as it contacts Grubb's catalyst, a ruthenium-based chemical, that is present in the composite.
The research team, led by Scott White of UI's Department of Aeronautical and Astronautical Engineering, has been going on for about six years, according to Nancy Sottos, one of the researchers. Past supporters included the U.S. Air Force.
The eight-member team reported its results in the Feb. 15 issue of the scientific periodical Nature. Since then it has been deluged with requests for information, said Sottos, a professor at UI's Department of Theoretical and Applied Mechanics. She hopes the publicity will help garner support for a research center on autonomously healing materials.
Sottos said in a telephone interview that she and the other researchers will expand the project. So far it has encompassed low-temperature-curing epoxies common to commodity applications. The group will look at high-temperature curing polymers, thermoplastics and other catalyst and monomer systems. Its published paper described the monomer's encapsulation in a urea-formaldehyde coating in a small-scale experiment. Industrial applications could require a tougher coating that would withstand pressures of typical mixing and compounding equipment.