Biocides for Antifouling Marine Coatings – Issues in Reactivity, Performance, and Ecotoxicity

For centuries, owners of private, commercial and military sea vessels have attempted, with varying degrees of success, to surface treat their underwater hulls with coatings to prevent the adhesion and/or growth of large fouling organisms that cause severe drag, reducing vessel speed and maneuverability, and increasing fuel consumption. Two major approaches are currently under development: (1) “easy release” coatings, usually employing silicones or fluoropolymers designed to prevent strong adhesion of foulants, and (2) “ablative/selfpolishing” coatings, which typically contain a rapidly ecodegradable biocide which is toxic to foulants upon release, and is slowly but continuously released from the coating during its ablative process. Critical performance issues currently limit use of the easy release coatings to a relatively small number of vessels. For large commercial and military vessels, the more mature ablative antifouling coatings with biocides are necessary to maintain adequate operability.