Healing the iPhone's wounds

In a paper published on Jan. 10, in Nature Nanotechnology, a team of researchers from the University of Pittsburgh and the University of Massachusetts Amherst (UMass) propose a "repair-and-go" approach to fixing malfunctions caused by small-surface cracks on any digital device or part before it hits store shelves.

"Anything that's a machine with a surface is affected by these small-scale cracks," said Anna Balazs, Distinguished Professor of Chemical and Petroleum Engineering in Pitt's Swanson School of Engineering and coinvestigator on the project. "These are surfaces that play a role in almost anything, especially functionality."

The Pitt-UMass research team approach was inspired by the ability of white blood cells in the body to heal wounds on-site. Balazs and Pitt colleagues first came up with a theoretical "repair-and-go" method: A flexible microcapsule filled with a solution of nanoparticles would be applied to a damaged surface; it would then repair defects by releasing nanoparticles into them. Using nanoparticles and droplets of oil stabilized with a polymer surfactant -- compounds that lower the surface tension of a liquid -- the UMass team actualized the theory, showing that these microcapsules found the cracks and delivered the nanoparticle contents into them. Balazs proposes that manufacturers use this method as a last step in the building process.

"The repair-and-go method can extend the lifetime of any system or device," she said. "Additionally, it could be used as a repair method after a crack has been found."

Original research by Balazs and her team was published in ACS Nano and then reported on in Nature Nanotechnology's "News and Views" section in September 2010.