July 1, 2008 Chemists created a paint embedded with pressure-sensitive capsules that contain a contrastingly colored dye. Violent scratches, dents, or strikes cause the capsules to burst. Visual inspections for changes in the color of the paint allow inspectors to pinpoint potentially damaged areas.
Airplanes are visually inspected everyday, but tiny cracks and flaws on planes can be easily missed. Now, a new kind of paint could expose hidden damage on planes.
Flying a plane is a lifelong passion for Doug Juanarena. "And just the freedom and you're alone up there … its got that element of excitement," Juanarena told Ivanhoe.
Whether you're a passenger or a pilot, on a private plane or a commercial jetliner, the excitement of flying can turn dangerous if the aircraft is damaged. "My airplane for example was pulled into a hanger door by the ground crew, they didn't report the damage … had I not caught it, it could have again caused a potentially bad situation in the air," Juanarena said.
Undetected damage, like tiny cracks, flaws or weak points, is a big problem on airplanes. Now, chemists are testing a new paint that changes color to instantly reveal damage on planes.
"So, it's tuned to be able to release a dye to be able to change different color based on the level of impact," Bryan Koene, Ph.D., chemist at Luna Innovations told Ivanhoe.
Microcapsules containing a colored dye are mixed together with aircraft paint. If the paint is scratched, dented, or struck the capsules break, releasing the dye. The change in color pinpoints damage. Visual inspections are easier and more accurate.
"This technology is important to be able to detect damage very simply and cheaply," Dr. Koene said.
The new paint is being developed first for the military.
Next, it will be used on commercial and private planes. Until then, Juanarena will rely on his own eyes for damage control. "In my case I have a pretty good eye for detail, and just saw it, and when I did find it, of course the ground crew owned up to it," said Juanarena. Another potential use for the color changing paint -- tamper resistant packaging.
SENSITIVE PAINT: Capsules of dye that can be included in paint make safety inspections of airplane exteriors easier. Collisions or other stresses break apart the capsules, releasing a contrastingly colored dye, bringing attention to areas which may be weakened structurally. This is especially important with modern aircraft exteriors made of polymer composites which do not absorb damage in the same way as metal exteriors. Color changes will alert inspectors to inspect damage that could otherwise prove easy to skip over.
ALL ABOUT PAINT: The technical definition of paint is any liquid substance that converts into an opaque solid film after being applied to a surface in a thin layer. We think of paint as being used for decorative purposes, such as adding color to the walls and trim in a room. But paint can also be used to protect a surface, such using it to slow the corrosion process of metal. It can also have added functions, such as improving the light reflection or heat radiation of a surface. Paint has three primary components: pigments (for color), binder, and a “vehicle,” also called solvent. The solvent is critical to determining the thickness and flow of the paint. The solvent also serves as a carrier for the binder and pigments. Many paints also contain surfactants: agents that allow more space between the molecules of a liquid. This means it can be more easily spread onto a surface. Extra additives can also give the liquid properties like antifreeze, long-lasting color, or antimicrobial capability.
The Materials Research Society contributed to the information contained in the TV portion of this report.