Static Electricity in Rain May Damage Protective Coatings on Metal Structures

On August 26, a study in Nature highlighted how electrically charged raindrops can harm protective metal coatings via micro-discharges. Conducted by researchers at the Max Planck Institute for Polymer Research, led by Hans-Jürgen Butt and Zhongyuan Ni, the investigation revealed that Teflon-coated copper was compromised after being struck by 3,000 electrified droplets, resulting in pitting, while plain water caused no damage. The droplets, carrying charges between 0.2 and 2.0 nanocoulombs, exhibited potential differences surpassing 1,000 volts. This occurrence, termed triboelectric charging, contradicts earlier assumptions about liquids. Although thicker coatings on ships and cars offer better protection, this may shed light on the deterioration of historical structures. Corrosion incurs over $2 trillion in annual costs for the U.S.