On the self-stratification mechanism of epoxy/silicone fouling control coatings: Effect of formulation and external parameters

Self-stratifying coatings, coatings spontaneously forming multiple layers in a single step application, hold great potential to bring significant ecological and economic benefits to different industries. The advantages of self-stratifying coatings can be particularly valuable in the commercial shipping sector, where frequent recoating of multilayer coating systems associated with complex application procedures is a substantial challenge. The present study focuses on the production and mechanism of self-stratifying coatings based on a mixture of a thermosetting epoxy and a room-temperature-vulcanizing (RTV) silicone, which could potentially be applied as a ship hull coating. The influence of various parameters arising from the coating formulation, such as the type of organic solvent, and external factors on the final coating morphology were schematically investigated and analyzed using scanning electron microscopy. Self-stratification was primarily influenced by the type of organic solvent used, with negligible effects from gravity and only a marginal influence from the surface tension of the substrate.