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Pittsburgh engineering team proposes composites that can regenerate when damaged

News International-French

27 Nov 2013

Researchers at the University of Pittsburgh Swanson School of Engineering have developed computational models to design a hybrid material of nanorods embedded in a polymer gel that would enable complex materials to regenerate themselves.

When a chair leg breaks or a cell phone shatters, either must be repaired or replaced. But what if these materials could be programmed to regenerate-themselves, replenishing the damaged or missing components, and thereby extend their lifetime and reduce the need for costly repairs?

That potential is now possible according to researchers at the University of Pittsburgh Swanson School of Engineering, who have developed computational models to design a new polymer gel that would enable complex materials to regenerate themselves. The article, “Harnessing Interfacially-Active Nanorods to Regenerate Severed Polymer Gels” (DOI: 10.1021/nl403855k), was published November 19 in the American Chemical Society journal Nano Letters.

Principal investigator is Anna C. Balazs, PhD, the Swanson School’s Distinguished Robert v. d. Luft Professor of chemical and petroleum engineering, and co-authors are Xin Yong, PhD, postdoctoral associate, who is the article’s lead author; Olga Kuksenok, PhD, research associate professor; and Krzysztof Matyjaszewski, PhD, J.C. Warner University Professor of Natural Sciences, department of chemistry at Carnegie Mellon University.

The research team was inspired by biological processes in species such as amphibians, which can regenerate severed limbs. This type of tissue regeneration is guided by three critical instruction sets – initiation, propagation, and termination.

The team developed a hybrid material of nanorods embedded in a polymer gel, which is surrounded by a solution containing monomers and cross-linkers (molecules that link one polymer chain to another) in order to replicate the dynamic cascade. When part of the gel is severed, the nanorods near the cut act as sensors and migrate to the new interface. The functionalized chains or “skirts” on one end of these nanorods keeps them localized at the interface and the sites (or “initiators”) along the rod’s surface trigger a polymerization reaction with the monomer and cross-linkers in the outer solution. Drs. Yong and Kuksenok developed the computational models, and thereby established guidelines to control the process so that the new gel behaves and appears like the gel it replaced, and to terminate the reaction so that the material would not grow out of control.

The next generation of research would further optimize the process to grow multiple layers, creating more complex materials with multiple functions.

More information: www.engineering.pitt.edu