Preparation, characterization, and antibacterial activity of cationic nanopolystyrenes

Cationic nanopolystyrenes (CNPSs) were prepared by the polymerization of styrene with a cationic polymerizable emulsifier, N-(2-(methacryloyloxy)ethyl)-N,N-dimethyltetradecane-1-ammonium bromide (MDTB), in the presence of 2,2 '-azobis(2-methylpropionamidine) dihydrochloride (APPH). The polymerization kinetics was investigated through monomer conversion versus polymerization time. H-1 NMR spectra and FTIR spectra were used to confirm the structures of MDTB and nanopolymers. The particle size, zeta-potential, molecular weight, and thermal stability were also investigated by Zetasizer, gel permeation chromatography, and thermogravimetric analysis, respectively. The antibacterial activities of the obtained products were evaluated by minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against Staphylococcus aureus ATCC 29913 (S. aureus, a Gram-positive bacterium) and Escherichia coli ATCC 25922 (E. coli, a Gram-negative bacterium). The results indicated that the polymerization has the characteristics of microemulsion polymerization, all nanopolystyrenes are cationic and can be stored in the form of a microemulsion in aqueous phase, CNPSs present stable chemical structure at 190 degrees C, and their MIC and MBC reach 0.0625 and 0.125 mg mL(-1) for E. coli, 0.0325 and 0.0625 mg mL(-1) for S. aureus, respectively. Therefore, CNPSs are a promising new type of polymer antimicrobial agent, which can be used in the development of antimicrobial polymer materials and their products. (c) 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 48405.