Benzisothiazole‐Anchored Aspartic Polyurea Coatings With Synergistic Antifouling and Anticorrosion Properties

Biofouling and corrosion of marine equipment are notable concerns for the offshore industry, and polymeric coatings offer a cost‐effective and practical solution. This study reports the synthesis of benzisothiazole‐anchored polyaspartic polyurea coatings (LBPU _X ), incorporating disulfide bonds with nonleachable benzisothiazole. Disulfide and hydrogen bonds form a dense cross‐linked network within the coating, enhancing its toughness, with a maximum elongation at break of up to 2800%. The introduced benzothiazole group further improves the antifouling performance of coatings, achieving >80% resistance to algae and >96% resistance to mussels. The antifouling efficacy of the prepared LBPU _X is evaluated under real‐world conditions in a marine field test, where trace levels of biofouling is observed on the LBPU ₂₀ coating after 12 months of immersion. In addition, the LBPU _X coatings can chelate with metal substrates to form a passivation layer, enhancing corrosion resistance. After 15 days of immersion in a 3.5 wt% sodium chloride solution, the low‐frequency impedance modulus (|Z| _0.01Hz ) of LBPU _X coatings remains above 10 ⁸  Ω cm ² . This study presents an innovative strategy for developing polyurea‐based marine protective coatings with synergistic antifouling and anticorrosion properties.