Mechanically robust antifouling coating with dual-functional antifouling strategy by infiltrating PDMS into plasma-sprayed porous Al2O3-Cu coating

Marine biofouling is a worldwide challenge that needs to be solved urgently. Poly(dimethylsiloxane) (PDMS)-based fouling release coatings with low surface free energy (SFE) could effectively inhibit biofouling. Nevertheless, their poor mechanical durability, adhesive strength, and antifouling performance under static conditions significantly limit their applications. Herein, a novel mechanically robust Al2O3-PDMS-Cu composite coating with strong adhesive strength and remarkable antifouling performance was developed. The Al2O3-PDMS-Cu coating loaded with a small amount of Cu was fabricated by infiltrating PDMS into plasma-sprayed micro/nano-scaled porous Al2O3-Cu coating. Results showed that the fabrication of this Al2O3-PDMS-Cu coating did not alter the surface hydrophobicity and SFE of PDMS significantly, thus presenting little influence on its inherent fouling release property. After rigorous abrasion test, the Al2O3-PDMS-Cu coating presented remarkably improved surface hydrophobicity due to the exposure of micro/nano structure, rather than falling off as that of PDMS coating. The combination of excellent abrasion resistance and one order of magnitude higher adhesive strength and hardness than PDMS coating contributed to the outstanding mechanical robustness of Al2O3-PDMS-Cu coating. Additionally, the antifouling assays against marine bacteria adhesion (95% reduction rate for Escherichia coli. (E. coli)) and algae attachment (96% and 94% reduction rates for Chlorella and Phaeodactylum tricornutum (P. tricornutum), respectively after 21 days of incubation) demonstrated the superior antifouling performance of the Al2O3-PDMS-Cu coating. Thus, a high-performance Al2O3-PDMS-Cu antifouling coating with excellent mechanical robustness and long-term antifouling performance was achieved via the combination of mechanical durability of Al2O3 skeleton and the dual-functional antifouling strategy, i.e., the fouling release property of PDMS and fouling resistance of Cu.