Surface hydrolysis-anchored eugenol self-polishing marine antifouling coating.

Traditional self-polishing antifouling coatings kill surface organisms by releasing toxic substances, which are damaging to the ecosystem. As a natural antimicrobial substance, eugenol is environmentally friendly and has been proven by different research teams to be effective in enhancing the anti-fouling effect of coatings in the real sea. While in these previous research works, the eugenol was released directly into the seawater thus cannot further serve as surface antifouling effect, leading to a limited antifouling effect of the coating. In this work, the quaternary ammonium component was introduced into the butyl ester-based resin - poly (eugenol methacrylate - acryloyloxyethyltrimethyl ammonium chloride - hexafluorobutyl methacrylate - methyl methacrylate - butyl methacrylate - ethylene glycol methyl ether acrylate) (EMQFP) coating for the first time by simple one-step free radical polymerization method. On the one hand, the eugenol produced by hydrolysis is anchored to the quaternary ammonium on the coating surface for a period of time due to the cationic-π interaction, instead of being released into seawater immediately after hydrolysis, thus increasing the utilization rate of eugenol; on the other hand, the negatively charged carboxylate groups generated after hydrolysis in the coating are mutually attracted to quaternary ammonium through electrostatic effect, so the resin chain segment conformation on the coating surface adjusted to produce zwitterionic-like structure, and the hydration of zwitterionic inhibits primary fouling adhesion.

Three-dimensional flower-like shaped Bi5O7I particles incorporation zwitterionic fluorinated polymers with synergistic hydration-photocatalytic for enhanced marine antifouling performance.

Herein, several novel composite films consisting of three-dimensional (3D) Bi5O7I flower-like shaped microsphere and zwitterionic fluorinated polymer (ZFP) were successfully fabricated with the aim of achieving high anti-fouling performance. The prepared Bi5O7I flower-like shaped microsphere particles with diameters in the range of 2∼3 µm were uniformly distributed on the surface and in the internal of ZFP. Benefiting from the hydration layer formed by the ZFP and the efficient photocatalytic performance of Bi5O7I flower-like microsphere, the resultant optimized Bi5O7I/ZFP composite film exhibited an excellent diatom anti-settling performance and a high antibacterial rate of 99.09% and 99.66% towards Escherichia coli and Staphylococcus aureus. In addition, the composite films possessed the strengthened visible light absorption, the effectively separation and transfer of the photo-induced electrons and holes, the large number of hydroxyl (OH) radicals and superoxide radicals (O2-) all in Bi5O7I/ZFP systems, all of which were beneficial for the photocatalytic antifouling activity. More importantly, the synergistic hydration-photocatalytic effect of the Bi5O7I/ZFP composite films are answerable for the improvement of the antifouling property compared to the control. Thus, the synergistic hydration-photocatalytic contribution of Bi5O7I/ZFP composite film will shows promise for potential application in marine antifouling.