[TheForge] New hope for Outdoor Ironwork

[Rob Fertner]

New polymer coatings prevent corrosion
by Staff Writers
Champaign, Ill. (UPI) Dec 17, 2008 
U.S. scientists say they are developing new polymer coatings that will not
only protect materials, but also help tiny scratches "heal" themselves. 
University of Illinois researchers said applications for the coatings range
from automotive paints and marine varnishes to the thick, rubbery coatings
on patio furniture and park benches. 
"Starting from our earlier work on self-healing materials Â
 we have now
created self-healing coatings that automatically repair themselves and
prevent corrosion of the underlying substrate," said Professor Paul Braun,
corresponding author of the study. 
The scientists said they first encapsulate a catalyst into spheres less than
100 microns in diameter -- a micron is 1 millionth of a meter. They also
encapsulate a healing agent into similarly sized microcapsules. The
microcapsules are then dispersed within the desired coating material and
applied to the substrate. 
"By encapsulating both the catalyst and the healing agent, we have created a
dual capsule system that can be added to virtually any liquid coating
material," said Braun. When the coating is scratched, some capsules break,
spilling their contents into the damaged region. The catalyst and healing
agent react, repairing the damage within minutes or hours, depending upon
environmental conditions. 
A paper detailing the research has been accepted for publication in the
journal Advanced Materials.