Formation of Antifouling Brushes on Various Substrates Using a Melanin-Inspired Initiator Film

In this study, we developed a substrate-independent initiatorfilmthat can undergo surface-initiated polymerization to form an antifoulingbrush. Inspired by the melanogenesis found in nature, we synthesizeda tyrosine-conjugated bromide initiator (Tyr-Br) that contains phenolicamine groups as the dormant coating precursor and alpha-bromoisobutyrylgroups as the initiator. The resultant Tyr-Br was stable under ambientair conditions and underwent melanin-like oxidation only in the presenceof tyrosinase to form an initiator film on various substrates. Subsequently,an antifouling polymer brush was formed using air-tolerant activatorsregenerated by electron transfer for atom transfer radical polymerization(ARGET ATRP) of zwitterionic carboxybetaine. The entire surface coatingprocedure, including the initiator layer formation and ARGET ATRP,occurred under aqueous conditions and did not require organic solventsor chemical oxidants. Therefore, antifouling polymer brushes can befeasibly formed not only on experimentally preferred substrates (e.g.,Au, SiO2, and TiO2) but also on polymeric substratessuch as poly(ethylene terephthalate) (PET), cyclic olefin copolymer(COC), and nylon.

Automated summary

In this study, a substrate-independent initiator film was developed to form an antifouling brush through surface-initiated polymerization. Inspired by melanogenesis, a tyrosine-conjugated bromide initiator (Tyr-Br) containing phenolic amine groups as the coating precursor and alpha-bromoisobutyryl groups as the initiator was synthesized. The Tyr-Br underwent melanin-like oxidation in the presence of tyrosinase to form an initiator film on various substrates, and an antifouling polymer brush was subsequently formed through air-tolerant activators regenerated by electron transfer for atom transfer radical polymerization (ARGET ATRP) of zwitterionic carboxybetaine. The entire surface coating process occurred under aqueous conditions without the need for organic solvents or chemical oxidants, allowing the formation of antifouling polymer brushes on different substrates.