Hyperbranched antibacterials show much more potential performances than their small molecules due to unique structure. Polyhexamethylene biguanide (PHMB) functionalized hyperbranched poly(amide-PHMB)s (DPBs) were prepared and their antibacterial properties were investigated using several techniques. The results showed that Gram-positive organisms were more susceptible than Gram-negative bacteria for DPBs, N1, N3, N5-tris(2-aminoethyl)benzene-1,3,5-tricarboxamide (DT) and PHMB. DPBs had better comprehensive properties than DT and PHMB, and the best one was DPB1. SEM and AFM were utilized to investigate the interactions between DPB1 and bacterial membranes of E. coli. The mode of action of DPB1 was revealed by the morphological images, which was consistent with bactericidal mechanism of cationic antibacterial agents.

Keywords: hyperbranched polymer; polyhexamethylene biguanide; antimicrobial activity; antimicrobial mechanism