Probing and repairing damaged surfaces with nanoparticle-containing microcapsules.
Nanoparticles have useful properties, but it is often important that they only start working after they are placed in a desired location. The encapsulation of nanoparticles allows their function to be preserved until they are released at a specific time or location, and this has been exploited in the development of self-healing materials and in applications such as drug delivery. Encapsulation has also been used to stabilize and control the release of substances, including flavours, fragrances and pesticides. We recently proposed a new technique for the repair of surfaces called 'repair-and-go'. In this approach, a flexible microcapsule filled with a solution of nanoparticles rolls across a surface that has been damaged, stopping to repair any defects it encounters by releasing nanoparticles into them, then moving on to the next defect. Here, we experimentally demonstrate the repair-and-go approach using droplets of oil that are stabilized with a polymer surfactant and contain CdSe nanoparticles. We show that these microcapsules can find the cracks on a surface and selectively deliver the nanoparticle contents into the crack, before moving on to find the next crack. Although the microcapsules are too large to enter the cracks, their flexible walls allow them to probe and adhere temporarily to the interior of the cracks. The release of nanoparticles is made possible by the thin microcapsule wall (comparable to the diameter of the nanoparticles) and by the favourable (hydrophobic-hydrophobic) interactions between the nanoparticle and the cracked surface.
Polymer Science and Engineering Department, University of Massachusetts, 120 Governors Drive, Conte Center for Polymer Research, Amherst, Massachusetts                 01003, USA.
Katrina
K
Kratz
Amrit
A
Narasimhan
Ravisubhash
R
Tangirala
SungCheal
S
Moon
Ravindra
R
Revanur
Santanu
S
Kundu
Hyun Suk
HS
Kim
Alfred J
AJ
Crosby
Thomas P
TP
Russell
Todd
T
Emrick
German
G
Kolmakov
Anna C
AC
Balazs
D019187:Cadmium Compounds / Q000737:chemistry*; D002214:Capsules / Q000737:chemistry; D016503:Drug Delivery Systems; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D053758:Nanoparticles / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry; D018036:Selenium Compounds / Q000737:chemistry*; D013499:Surface Properties; D013501:Surface-Active Agents / Q000737:chemistry
D019187:Cadmium Compounds; D002214:Capsules; D011108:Polymers; D018036:Selenium Compounds; D013501:Surface-Active Agents; C058667:cadmium selenide