In this month’s cover story in the journal Advanced Materials, polymer scientists Todd Emrick, Al Crosby and colleagues describe a new approach using liquids for simultaneously cleaning nanoparticle debris from surfaces and depositing that debris into damaged regions of the same surfaces, a process that quickly and efficiently “heals” them.
As Emrick recently told the editor of the “Spotlight” feature for the online nanotechnology news service Nanowerk, “For many types of structural materials, we wish to rapidly detect damage and discover mechanisms to quickly heal those damaged regions. Ideally a detection and repair system would deploy so rapidly that repair would begin before damage becomes severe. Our approach seeks to move in that direction – autonomous, easily deployed, and efficient transport/delivery/healing systems for materials.”
Applications include any type of structural material,from automotive coatings to microfluidic devices to bio-implants, in which one wants rapid healing immediately after damage, he adds.
For this project supported by the Department of Energy’s Office of Basic Energy Sciences, Division of Materials Science and Engineering, the researchers used oil-in-water droplets stabilized by functional polymer surfactants as “smart droplets,” he explains, that are easy to use and able to recognize, pick up, transport, and drop off the nanoparticles, all in one flow system design. “Biology routinely carries out complicated tasks of recognition, transport, healing and so on, and yet it is challenging to extend such concepts to materials systems. In that sense, our paper represents an exciting step in that direction,” Emrick notes.
In the advance inspired by biological systems, he says, “We can take a material that has debris all over it, and use droplets to selectively move that debris into the damaged (cracked) regions of the structure. One can easily imagine translating this advance to situations where one could massively conserve the amount of material used in healing a damaged structure, that is, rather than applying a new coating on the entire material.”
The researchers acknowledge facing “a long list of future challenges, including how to best integrate our findings with practical systems in a non-laboratory environment,” Emrick adds, “but these challenges are not insurmountable and we have several routes in mind towards reducing our findings to practice.”