Stable poly(St-co-BA) nanoemulsion polymerization for high performance antibacterial coatings in the presence of dioctyldimethylammonium chloride

• Stable poly(St-co-BA) nanoemulsions and high-performance coatings were prepared.
• These polymerizations were in the presence of D821–CTAB mixed surfactant systems.
• Novel bis-unsaturated comonomer, GMAP-6-MAP was added into these polymerizations.
• MBCs of this nanoemulsion were lower than 16 μg·mL− 1 against S. aureus or E. coli.
• Sterilization rates of the coatings were more than 98% against S. aureus or E. coli.

In this study, a stable antibacterial poly(styrene-co-butyl acrylate) (poly(St-co-BA)) nano-latex was prepared in the presence of a dioctyldimethylammonium chloride (D821)-CTAB mixed surfactant and a novel bis-unsaturated Gemini comonomer (i.e., α,ω-hexanediyl bis(dimethyl methacrylamidopropyl ammonium bromide) (GMAP-6-MAP)) using a feasible and mild semicontinuous technology. The effects of the emulsifiers and GMAP-6-MAP on the properties and antibacterial activities of poly(St-co-BA) coatings were systematically investigated. The results indicate that an optimal monodispersed stable nanoemulsion was obtained with Dw = 58.24 nm and PDI = 0.026, the emulsifier amount was 3.75% (D821/CTAB = 4:1), and the GMAP-6-MAP amount was 1.5%. CTAB improved the stabilities and antibacterial activities of the poly(St-co-BA) nanoemulsions. The incorporation of GMAP-6-MAP into poly(St-co-BA) can enhance the antibacterial activity, improve the thermal stability of latex films, as well as the consistency among the chain segments, and decrease the roughness of latex films. This nanoemulsion exhibits effective antibacterial activity with MBCs of 2 μg·mL− 1 against Staphylococcus aureus and 16 μg·mL− 1 against Escherichia coli. The sterilization rates of the optimized latex film reached 100% against S. aureus and 98.74% against E. coli, which indicated that this latex film could be utilized as an outstanding antibacterial coating.

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