Characteristics, antibacterial activity, and antibiofilm performance of a polysiloxane coating filled with organically modified Cu 2 O

The effects of Cu 2 O nanoparticles (Cu 2 O NPs) modified with 3-(trimethoxysilyl)propyl methacrylate (TMSPM) (m-Cu 2 O NPs) on the properties of a polysiloxane (PS) coating were investigated. The organic surface modifications improved the antimicrobial activity of the Cu 2 O NPs and their dispersion in a PS matrix. Due to the broad dispersion of the m-Cu 2 O NPs, the PS/m-Cu 2 O coating exhibited better mechanical properties and better thermal stability than unmodified Cu 2 O (u-Cu 2 O) coatings. The onset temperature of PS/m-Cu 2 O was 24 °C higher than that of the neat PS coating and 11 °C higher than that of the PS/u-Cu 2 O coating. The PS/m-Cu 2 O coating exhibited high antibacterial activity for sulfate-reducing bacterial strains, but the PS/m-Cu 2 O coating showed slight bacterial inhibition of Pseudomonas stutzeri B27 bacteria (which were isolated under seawater at Phu Quoc Island, Kien Giang Province, Vietnam). Biofilm inhibition by the PS coatings with and without the m-Cu 2 O NPs was also tested with a natural seawater immersion test. After a 60-day test, the biofilm formed on the PS coating surface was ten times thicker than that on the PS/m-Cu 2 O coating. Fourier transform infrared spectroscopy (FTIR) data and the surface properties of the coating indicated that immersion in natural seawater insignificantly affected the functional groups of the coating but had a substantial influence on the smoothness of the coating, which made the surface of the coating more hydrophilic. These results suggested that the PS/m-Cu 2 O could be used as an antifouling coating for the marine industry.