ZnS:Cu/PDMS Composite Coating for Combating Marine Biofouling

Biofouling is a major concern in marine industries. The use of traditional toxic antifouling coatings is forbidden or severely restricted. This study aimed to provide a green and effective antifouling coating. The coating was prepared using a polydimethylsiloxane (PDMS) matrix and Cu-doped zinc sulfide (ZnS:Cu). Four samples with different ZnS:Cu contents (1, 10, 20, and 50 wt%) were prepared. Pristine PDMS (0 wt%) was used as the control. The results showed that all coatings had hydrophobic surfaces conducive to combating biofouling. In tests against B. Subtilis, the 1, 10, 20, and 50 wt% samples showed enhanced antifouling capabilities compared to the 0 wt% sample. In static and dynamic tests against Chlorella, the antifouling capability increased with increasing ZnS:Cu content and the 50 wt% sample showed the best antifouling capability. The possible antifouling mechanisms of these coatings include the release of ions (Zn2+ and Cu+), induction of deformation, and fluorescence emission. This study provides a reference for the application of Zn2+/Cu+ combinations to combat marine biofouling.