Numerous　antimicrobial　coatings　have　been　developed　for　biomedical　devices/implants,　but　few　can　simultaneously　fulfill　the　requirements　for　antimicrobial　and　antifouling　ability　and　biocompatibility.　In　this　study,　to　develop　an　antimicrobial　and　antibiofilm　surface　coating,　diblock　amphiphilic　molecules　with　antimicrobial　and　antifouling　segments　in　a　single　chain　were　rationally　designed　and　synthesized.　Cationic　antimicrobial　polypeptides　(AMP)　were　first　synthesized　by　N-carboxyanhydride　ring-opening　polymerization　(NCA-ROP).　Heterofunctionalized　poly(ethylene　glycol)　with　different　lengths　(methacrylate-PEG(n)-tosyl,　n　=　10/45/90)　was　synthesized　and　site-specifically　conjugated　with　polypeptides　to　form　diblock　amphiphiles.　Along　with　increased　PEG　chain　length,　hemolytic　activity　was　considerably　improved,　and　broad-spectrum　antimicrobial　activity　is　retained.　Three　MA-PEGSb-AMP　copolymers　were　further　grafted　onto　the　surface　of　silicone　rubber　(a　commonly　used　catheter　material)　via　plasma/UV-induced　surface　polymerizations　to　form　a　bottlebrush-like　coating　with　excellent　antimicrobial　activity　against　several　pathogenic　bacteria　(Escherichia　coli,　Pseudomonas　aeruginosa,　and　Staphylococcus　aureus),　and　effectively　prevent　biofilm　formation.　This　bottlebrush　coating　also　greatly　reduced　protein　adsorption　and　platelet　adhesion,　indicating　its　excellent　antifouling　ability.　An　in　vitro　cytotoxicity　study　also　demonstrated　that　this　coating　is　biocompatible　with　mammalian　cells.　After　subcutaneous　implantation　of　the　materials　in　rats,　we　demonstrated　that　the　g-PEG(45)-b-AMP　bottlebrush　coating　exhibits　significant　anti-infective　activity　in　vivo.　Thus,　this　facilely　synthesized　PEGylated　AMP　bottlebrush　coating　is　a　feasible　method　to　prevent　biomedical　devices-associated　infections.　Statement　of　Significance　Current　antimicrobial　coatings　are　often　associated　with　concerns　such　as　antibiotic　resistance,　environmental　pollution,　short-time　antimicrobial　activity,　biofouling,　poor　blood　compatibility　and　cytotoxicity,　etc.　To　overcome　these　drawbacks,　a　robust　PEGylated　cationic　amphiphilic　peptides-based　bottlebrushlike　surface　coating　is　demonstrated　here,　which　fulfil　the　requirements　of　antimicrobial　and　antifouling　as　well　as　biocompatibility　in　the　meantime.　Briefly,　the　rational　designed　g-PEG(n)-b-AMP　block　copolymers　(n　=　10/45/90)　were　synthesized　and　grafted　on　silicone　surface.　This　bottlebrush-like　coating　efficiently　kill　the　contacted　bacteria　and　prevent　the　biofilm　formation,　greatly　reduced　protein　and　platelet　adhesion.　It　also　exhibits　excellent　blood　compatibility　and　low　cytotoxicity　in　vitro.　In　particular,　gPEG(45)-b-AMP　coating　exhibits　significant　anti-infection　effect　in　vivo.　This　coating　offering　an　effective　strategy　for　combating　biomedical　devices-associated　infections.　(c)　2017　Acta　Materialia　Inc.　Published　by　Elsevier　Ltd.　All　rights　reserved.