Biomedical device-related infections have been a great concern over the past decades. In this work, cationic macromolecules poly(1-vinyl-3-allylimidazolium iodide) (PAVI) with antibactericidal ability were prepared and grafted on nose clips by surface-initiated polymerization via plasma/autoclaving method. The precursor poly(1-vinylimidazole) was synthesized by surface-initiated polymerization and then quaternarized to form polymeric quaternary ammonia salts which have been commonly used as bactericidal materials. We first synthesized a series of different formulations of cationic PAVI and hydrophilic poly(ethylene glycol) dimethyl acrylate graftings onto nose clips by thermal-initiating polymerization with covalent bonds for antimicrobial surface modification. Antibacterial test results showed that the cationic-hydrophilic coatings exhibited excellent antibacterial behaviors for multidrug-resistant bacteria such as vancomycin-resistant Enterococcus and methicillin-resistant Staphylococcus aureus. The in vitro log reduction value for could reach 6.0 and 8.6, respectively, and the in vivo log reduction value could reach 1.3 and 2.0, respectively. In vitro cytotoxicity indicated that PAVI coatings were non-leachable and exhibited no toxicity toward mammal cells. This rationally designed polycationic antimicrobial coating displayed great potential application in combating implant-associated infections on biomedical devices. [GRAPHICS] .