Raindrops can damage paint with microscopic “lightning”

Scientists discovered that charged water droplets can damage protective coatings by releasing tiny electrical discharges when they hit a surface. The hidden effect could help explain weathering and lead to tougher coatings for cars, bridges, buildings, and more. Raindrops can damage paint with microscopic “lightning”.

Raindrops can damage paint with microscopic “lightning” Science News from research organizations Raindrops can damage paint with microscopic “lightning” Rain droplets may be quietly damaging paint and protective coatings with microscopic flashes of electricity. If they then fall onto a coating—such as on a car—the coating can be corroded by the drop’s electrical discharge and permanently damaged. A garden fence may need a fresh coat after only a few years because weather has gradually worn the surface down.

The same basic problem affects far larger structures, including the Eiffel Tower and the Golden Gate Bridge, which require extensive repainting to keep their protective coatings in good condition. Scientists have traditionally attributed this type of deterioration to two major processes. One is mechanical stress, in which repeated contact with water droplets creates friction that slowly erodes a coating or causes pieces of it to peel away.

The other is chemical damage, especially when the water contains substances such as acids or salts.