Analysis of the Antifouling Mechanism of Self-Polishing Antifouling Coatings Containing Zinc Pyrithione during Service

Abstract

In order to explore the composition, pH and concentration changes of the antifouling agent zinc pyrithione (ZPT) during the service process of zinc pyrithione-containing self-polishing antifouling coating (ZPT-SPC), and clarify the antifouling mechanism of ZPT-SPC during service, SEM/EDS were employed to explore the changes in cross-sectional micromorphology and composition of coatings before and after polishing. Moreover, the open circuit potential-pH experiment was used to measure the changes in the micro-potential-pH information of paint scratches. The changes in ZPT composition and content on the paint surface during service were explored through Raman spectroscopy. SEM/EDS results showed that the surface became denser, and the Zn element content decreased after polishing. Notably, the Zn content was much greater than the Cu content, which indicated that he ZPT content was much greater than the Cu2O content. In addition, the open circuit potential-pH measurement results showed that the pH value of the ZPT-SPC scratch interface generally exhibited a trend of first decreasing and then increasing, and eventually approached the original pH value. Raman results showed that the ZPT slowly diffused to the outside, which reduced the internal concentration, and the ZPT component transfer occurred inside the antifouling coating, resulting in a more uniform distribution of components. Furthermore, this process could be characterized macroscopically by antifouling agent concentration-color gray correlation model.

Keywords

• self-polishing antifouling coating|zinc pyrithione|sem/eds|potential-ph|raman spectroscopy