The management of long-term accumulation of bio-foulant growth on submerged surfaces is a perpetual effort of the marine industry. Balancing effectiveness with environmental impact is an essential consideration in the development and implementation of any antifoulant effort. One common avenue for decreasing foulant buildup is the impregnation of an antifoulant agent into polymer materials to discourage any biological growth on a surface. Early iterations of these embedded biocides utilize highly toxic organotin compounds; however, the most common industrially available antifoulant additives today are primarily organocopper and organozinc compounds, as well as select organic biocides.
Our interest in this system is specifically in the diffusion and leaching behavior of those incorporated biocidal materials over their service life, combined with the effect of the eventual buildup of bio-foulant on that diffusion process. The long-term leaching of the antifoulant compounds out of the polymeric materials is important for two reasoned: the reduction in effectiveness as an antifoulant agent, and the environmental impact of the release of the biocides into the marine habitats. We are experimentally collecting data from long-term leeching studies as well as foulant growth experimentation on selected materials. Based on this data, we have developed a 1-dimensional concentration dependent model to predict the diffusion of the antifoulant throughout the system. This concentration dependent model utilizes observed diffusion dependent growth conditions to predict the degree of fouling and depletion of effectiveness of the polymeric antifoulant matrix over time. The work will contribute to improvements to the service life and environmental impacts of polymer based marine antifouling materials and coatings.
