Sustainable eugenol release from cationic nanoparticles via accelerated hydrolysis of the biodegradable, fouling-release polysiloxane-polycaprolactone based antifouling coatings

Eco-friendly antifouling coatings based on biodegradable, fouling-release polycaprolactone-polydimethyl siloxane (PCL-PDMS) materials were developed by incorporating natural antifoulant eugenol releasing nanoparticles, i.e. cationic amphiphilic poly(lauryl methacrylate)-b-poly((dimethylaminoethyl methacrylate-(4-allyl-2-methoxyphenyl 2-chloroacetate)) (PLMA-b-P(DMAEMA-AMPCA)). The synthesized nanoparticles are capable of transforming their core-shell structure in water and immediately releasing eugenol via hydrolysis. The eugenol release kinetics and the structure transformation process of the cationic nanoparticles were monitored by ultraviolet-visible spectroscopy, which indicated that an instant and rapid release of eugenol can be achieved. Results showed that the surface renewal rate of the fabricated marine coating was accelerated by the cationic nanoparticles. Meanwhile, a controlled and sustainable release of eugenol was attained by regulating the content of the cationic segment in the coating. Three consecutive antibacterial tests demonstrated that the cationic structure, the released eugenol, as well as the self-replenishment of PCL-PDMS materials and nanoparticles, exhibited synergistic bactericidal effect. Marine field tests showed that the developed coatings can resist the biofouling of marine microorganisms for up to 120 days.