On the mechanism of marine fouling-prevention performance of oil-containing silicone elastomers: A comprehensive laboratory, field and theoretical study

For many decades, silicone elastomers with oil incorporated have served as fouling-release coating for marine applications. In a comprehensive study involving a series of laboratory-based marine fouling assays and extensive global field studies of up to 2-year duration, we compare polydimethylsiloxane (PDMS) coatings of the same composition loaded with oil. Methods using a traditional, one-pot pre-cure oil addition approach (o-PDMS) and a newer post-cure infusion approach (i-PDMS) were evaluated. The latter display a substantial increase in biofouling prevention performance that exceeds an established commercial silicone-based fouling-release coating standard. We interpret the differences in performance between one-pot and infused PDMS by developing a mechanistic model based on the Flory-Rehner theory of swollen polymer networks. Using this model, we propose that the chemical potential of the incorporated oil is a key consideration for the design of future fouling-release coatings, as the improved performance is driven by the formation and stabilization of an anti-adhesion oil overlayer on the polymer surface.