Marine biofouling is the process in which organisms such as barnacles problematically colonize underwater surfaces. When it happens to the hulls of ships, the vessels become less hydrodynamic, having to burn more fuel in order to move through the water. Although hulls can be coated with paint that kills the offending organisms, that paint also releases toxic substances into the surrounding water. Now, however, scientists from Germany’s Fraunhofer Institute for Mechanics of Materials have developed a more environmentally-friendly paint, that uses electrolysis to control biofouling.
The paint contains nanoscale electrically-conductive particles, and is applied over a non-conductive primer to isolate it from the ship’s steel hull. When the ship is docked (which is when most biofouling occurs), a weak electrical current is run through the paint. That electricity could come from a source such as an onboard photovoltaic panel, or land-based mains power.
Software is used to continuously interrupt the current or change its amplitude, the result being that the pH value of the paint’s outer surface is constantly changing – which the biofouling-causing organisms don’t like. In shipyard tests of the technology, hull patches coated with the paint reportedly remained much less colonized than untreated patches.
The researchers are now working on improving the technology, and hope that the paint could ultimately stand up to three to five years of use once applied.