Preparation and performance characterization of block cross-linked copolymers PCaPE(Br) and PCaPE(I) via RAFT polymerization and quaternization reaction

Abstract

Reversible addition–fragmentation chain transfer (RAFT) polymerization enables precise regulation of polymer chain growth and active center distribution. This study adopted a two-step approach with RAFT polymerization followed by quaternization to synthesize antibacterial materials, specifically tunable porous polymers PCaPE(Br) and PCaPE(I). The work focused on the structure–activity relationship between RAFT-derived block structures and the antibacterial properties of these materials. RAFT-mediated polymerization precisely controlled the block copolymer precursor PE-PDE, which is PEMA-b-P(DMAEA-co-EGDMA), and this control facilitated the subsequent formation of ordered porous structures. When the molar ratio of poly(ethyl methacrylate) (PEMA) to ethylene glycol dimethacrylate (EGDMA) was set to 1 : 6, the final quaternized products PCaPE₂(Br) and PCaPE₂(I) exhibited porous and fluffy microstructures. These microstructures were characterized by large specific surface area and high porosity. This structure, combined with uniformly distributed quaternary ammonium salt groups from the quaternization of N,N-dimethylaminoethyl acrylate (DMAEA) tertiary amine groups, enhanced the contact between antibacterial active sites and bacteria as well as antibacterial efficacy. PCaPE(Br) and PCaPE(I) showed excellent broad-spectrum antibacterial activity against E. coli and S. aureus. They also maintained good reusability with over 95% activity retention after five cycles. Such advantages support their prospects in biomedicine, agricultural antibacterials and wastewater treatment.