Development of bio-based and sustainable amphiphilic polymers for marine environmental application

Marine biofouling remains a major challenge for the shipping industry and marine infrastructure, causing economic losses, ecological risks, and safety concerns worldwide, and making the search for effective and sustainable antifouling strategies particularly urgent. In this project, bio-based platform chemicals derived from renewable resources such as sugars, fatty acids, or fermentation products, have been polymerized to form innovative amphiphilic systems incorporating hydrophilic monomers (acrylic acid, methacrylic acid, and the zwitterionic sulfobetaine methacrylate) and hydrophobic monomers (lauryl acrylate, lauryl methacrylate), with the hydrophilic–hydrophobic balance used as a design strategy to improve antifouling properties. Crosslinking in the coatings selected for performance testing was achieved through glycidyl methacrylate units cured with diethylenetriamine. Beyond synthesis, the research has evaluated the environmental sustainability of these systems by considering renewable sourcing of monomers, the avoidance of hazardous solvents, energy efficiency during free-radical polymerization, and the design of coatings that are non-toxic but effective. Antifouling potential was tested both in vitro, under controlled laboratory conditions, and in the field, in a touristic marina. Complementarily, questionnaires were conducted to evaluate the awareness of boaters regarding the issue of biofouling and the use of different coatings. In-vitro assays revealed almost complete inhibition of diatom adhesion for hydrophobic coatings, while amphiphilic systems showed moderate or formulation-dependent efficacy. In contrast, field tests on static PVC panels showed no antifouling effect, suggesting that the experimental setup was unsuitable for surface-active coatings requiring hydrodynamic shear. Overall, the study highlights promising coating candidates and identifies methodological improvements needed for a reliable assessment of their commercial use.