Tyrosine‐conjugated diethylene glycol (Tyr‐<scp>EG₂</scp>) as a small‐molecule material for universal antifouling surface coatings

Abstract This paper reports the development of a universal antifouling coating based on a small molecule, tyrosine‐conjugated diethylene glycol (Tyr‐EG 2 ). Tyrosine, a natural precursor in melanin biosynthesis, undergoes tyrosinase‐catalyzed oxidation to initiate film formation on various surfaces. Building on this principle, Tyr‐EG 2 was designed to form a melanin‐mimetic poly(Tyr‐EG 2 ) film through enzymatic oxidation under mild aqueous conditions (pH 7.4). In contrast to polymeric systems composed of repeating ethylene glycol and catechol units, which often suffer from batch‐to‐batch variations owing to their high molecular weight and structural complexity, Tyr‐EG 2 exhibits a well‐defined, low molecular weight, which enables consistent synthesis. Moreover, compared with catechol, the phenol‐based structure of Tyr‐EG 2 provides enhanced resistance to auto‐oxidation under ambient conditions. The resulting poly(Tyr‐EG 2 ) films exhibited excellent coating capabilities on a wide range of substrates, as well as antifouling properties, reducing nonspecific protein adsorption and marine organism adhesion. This simple, mild, and versatile strategy offers a practical platform for achieving antifouling coatings, which are required in the fields of biosensors, marine equipment, and medical devices.