Cationic polyesters with antibacterial properties: Facile and controllable synthesis and antibacterial study

[Display omitted] •The synthesis reaction of cationic polyester is simple and controllable.•The ionic content on the surface and chain length affect the antibacterial properties of cationic polyester.•When the alkyl chain length of is 12, it has good antibacterial activity. In this work, biodegradable antimicrobial cationic copolyesters were prepared via a simple two-step process. Firstly, brominated poly(butylene succinate) (BPBS) was prepared by addition of bromine to carbon–carbon double bonds on the backbone of poly(butylene succinate-co-butylene fumarate) (PBSF). Then, the quaternization of BPBS with series of N,N-dimethyl alkylamines afforded poly(butylene succinate) containing quaternary ammonium cations (QPBS) with various ion contents and alkyl chain lengths. The structures of BPBS and QPBS were systematically characterized by NMR, ATR-FTIR, GPC and XPS. The hydrophilicity and the antibacterial activity have been studied by water contact angle (WCA), inhibition zone method, optical density method and scanning electron microscope (SEM). WCA test indicates that the hydrophilicity of polyester is greatly improved after the introduction of quaternary ammonium cations. The antibacterial study reveals that cationic copolyesters exhibited excellent antibacterial performance for both S. aureus and E. coli when the alkyl chain length was greater than 8, as compared with the ion content and alkyl chain length is a more important factor for the antibacterial performance. Considering the biodegradation, good antibacterial activities and simple process, this kind of material may have great potential to be applied as biomaterials.