A silicone with one quaternary ammonium salt and three N-halamine sites in the repeating unit for improved antibiotic ability on submicrospheres

A silicone containing one cationic quaternary ammonium salt (QAS) and three N-halamine sites in the repeating unit was developed on SiO₂ submicron spheres for better antibacterial performance, larger bactericidal area and easier recyclability. Briefly, a precursor (NDAM) with high content of N-halamine was prepared by the amidation reaction. Then, a SiO₂@NDA nanocomposite was synthesized. Chlorination of the three imide NH bonds in the repeat unit finalized the synthesis of the bactericidal silicone (SiO₂@NDA-Cl). The synthetic steps and products were characterized and the effect of the contents of NDAM in copolymer on antibacterial activity were systematically assayed. The SiO₂@NDA-Cl showed higher deactivation abilities against both E. coli and S. aureus compared with their counterparts that contained only one cationic center or one N-halamine. This study has theoretical and practical application value for the development of new antibacterial materials.