Settlement behavior and mechanism of Navicula sp. on WLAP/PDMS composite coating under simulative diurnal alternation, constant light and dark conditions

Abstract

Marine biological fouling is a persistent issue facing the marine industries, which not only causes damage to the underwater facilities but also results in substantial financial losses. Diatoms are one of the most harmful polluters in the ocean. In this paper, novel antifouling coatings inspired by fluorescent coral were reported. Waterproof long afterglow phosphors (WLAP) were introduced into the cross-linked network of polydimethylsiloxane (PDMS). WLAP can absorb and store light energy during the day and emit weak fluorescence at night, which affects the normal physiological activities of diatoms. Through the synergistic mechanism of low surface energy and fluorescence antifouling, excellent antifouling performance is achieved throughout the day. The settlement behavior of Navicula sp. on WLAP/PDMS composite coatings was studied under simulative diurnal alternation, continuous light, and dark conditions. The results demonstrated that the adhesion of diatoms on WLAP/PDMS composite coatings decreased significantly under simulative diurnal alternation. The inhibition effect of the sky-blue composite coating was the most obvious. The attachment reduction rate (ARR) was 35.4% compared with the blank control coating, and the diatom removal rate (DRR) after washing was 42.3%. Constant light conditions also affect the normal physiological activities of diatoms, while the feeble light of coatings is covered. In continuous dark condition, the antifouling abilities of coatings mainly depend on their low surface energy. The composite waterborne coatings prepared in this research is non-toxic and eco-friendly and can recycle solar energy, which supply a new direction for enhancing the static antifouling ability of coatings and an environmentally friendly antifouling strategy, and becomes an important step for sustainable development.