Transmittance of PDMS film on the fluorescent performance and synergistic antifouling effect of SWLAP/PDMS composite coatings

Abstract

The film-forming substances in waterborne silicone coatings play a crucial role in the properties of coatings. A novel waterborne fluorescent antifouling coating inspired by fluorescent coral was reported in this paper. A series of sky-blue waterproof long afterglow phosphor (SWLAP)/polydimethylsiloxane (PDMS) composite coatings were prepared with different properties of hydroxy‑terminated silicone oil emulsion (HT-SOE). SWLAP is irradiated by sunlight during the day and emits fluorescence at night to interfere with the normal physiological activities of marine organisms. The high transmittance of PDMS films formed by HT-SOE contributes to the high fluorescence intensity of coatings. The adhesion behavior of marine bacteria and Navicula sp. on the coatings was studied under simulated alternative day-night, continuous light, and constant dark conditions. The results showed that the bacterial adhesion rate (BAR) and diatom removal rate (DRR) under simulated alternative day-night conditions of coatings was significantly decreased and increased, respectively. C-S20/5011 had the best static and dynamic antifouling performance. The BAR was only 2.46 % after 24 h and DRR reached 39.9 % after 48 h. Under continuous light or dark conditions, the antifouling abilities of coatings mainly depend on their surface performance and mechanical properties. The fluorescence effect played an important role in the synergistic antifouling mechanism. This study provides a new idea for environmentally friendly antifouling coatings and becomes an important step in the development of green and long-acting marine antifouling coatings.