Facile
methods for detecting and repairing damaged regions of materials are critically
important in numerous structural and functional materials, from airplane wings
to fabrics to microelectronics to biological implant materials. Emrick,
Crosby, and Russell,
working in the Materials Research Science and Engineering Center (MRSEC) on
Polymers at UMass Amherst, demonstrated that microcapsules can carry
nanoparticles across a damaged substrate, sense the damaged regions, and
deposit nanoparticles
selectively into the damaged areas, leaving the rest of the surface
unaffected. The work represents an
experimental realization of a theoretical challenge described by Balazs (U
Pittsburgh), termed “repair-and-go”. The
success of “repair-and-go” hinges on microencapsulation with polymer
surfactants, as the thin polymer capsule wall (the polymer structure of the
capsules is shown in the figure) allows nanoparticles to
pass out of the capsule and into the crack.
Moreover, the polymer is anti-fouling, preventing irreversible
absorption of the capsule on the substrate or in the damaged region.
