Novel polymeric micro/nano particles (MNPs) containing amide functional groups, poly (styrene-co-N-(t-Bu)-acrylamide) (PSA-NH) MNPs, have been synthesized by a copolymerization of styrene and acrylic acid and then an amination with tert-butylamine. The as-synthesized PSA-NH MNPs were converted to antibacterial polymeric MNPs containing N-halamine groups, poly (styrene-co-N-(t-Bu)-N-chlorine-acryl amide) (PSA-N-Cl) MNPs, by a facile chlorination in diluted NaOCl solution. The as-prepared PSA-N-Cl MNPs were characterized by field emission scanning electron microscopy (FE-SEM), Brunauer-Emmet-Teller (BET) analysis, X-ray photoelectron spectra (XPS), and Fourier Transform infrared spectroscopy (FTIR). Antibacterial tests showed that the as-prepared PSA-N-Cl MNPs possess powerful antibacterial activity against both Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Minimum inhibitory concentration (MIC) values of PSA-N-Cl MNPs against E. coli and S. aureus were 0.20 mu g/mL, whereas minimum bactericidal concentration (MBC) values of them against E. coli and S. aureus were 5.00 and 7.00 mu g/mL, respectively. The storage stability test indicated that PSA-N-Cl MNPs are very stable under common storage conditions. (C) 2014 Elsevier B.V. All rights reserved.