Self-Healing Paint Is Full of Magical Tiny Caulk Crystals

Autonomic Materials plans to bring self-healing paint to market in less than four months. The paint is designed to protect cars, bridges, and boats from corrosion, but don’t get too excited just yet:

The paint is unfortunately too rough to be used to stop those darn kids from keying your car because you won’t give them their frisbee back. It contains tons of tiny microcapsules of two types: one with polymer building blocks and the other with a catalyst. The capsules themselves are made of polyurethane to keep the chemicals isolated, and can be used in all kinds of paints, but each microcapsule is about 10 to 100 micrometers in diameter, which leaves the paint containing them rough to the touch and not suitable for locations where aesthetics are important.

When the paint is scratched, the microcapsules burst and spill out their chemical guts, which combine to form a material called siloxane, which the inventor describes as similar to bathroom caulk. This siloxane fills in the crack that created it, and thus we have self-healing paint. Its potential uses are widespread, from aeroplane wings (to stop fractures) to buildings and bridges. The paint is apparently ready to go commercial right now, and the inventors are just ironing out the financial details. They expect it to come to market in under four months. [Technology Review, photo credit: Paul Braun]