Charged Rain Breaks Through Coatings, Sparking Hidden Corrosion
New research shows raindrops carry enough electrical charge to electrostatically punch through insulating coatings, causing dielectric breakdown and exposing metal to corrosion. In experiments with charged drops hitting a thin Teflon layer over copper, thousands of impacts produced nanometer-scale pits and accelerated degradation, while uncharged drops left surfaces intact. The finding suggests rain-driven electrostatic damage could affect paints, plastics, composites, outdoor electronics, and historic structures, and that thicker or field-tolerant coatings may be needed to mitigate the effect.