Self‐Reinforcing Gradient Antifouling Coating with High Adhesion, On‐Demand Peelability, and Superior Recyclability

Abstract On‐demand peelable antifouling coatings can address the issue of coating failure due to high biofouling pressure through simple removal and meet the temporary antifouling needs of underwater equipment. However, such materials are rare due to the challenge of simultaneously fulfilling the requirements for high adhesion, on‐demand peelability, recyclability, and surface antifouling functionality. Herein, a novel strategy is presented for preparing a gradient antifouling coating with high adhesion, on‐demand peelability, and superior recyclability that involves the modular construction of three components that work together synergistically. Self‐reinforcing thiol‐capped polysilsesquioxane (POSS‐SH, module 1) reacts with isocyanate‐terminated polyurethane (NCO‐PU, module 2) to form a cross–linked network with strong cohesion, and reactive amphiphilic polymer (RAP, module 3) self‐enriches on the coating surface to exert fouling resistance against proteins, bacteria, diatoms, and biofilms. Meanwhile, the coating achieves strong adhesion to a substrate by hydrogen bonds and high recyclability owing to dynamic thiourethane bonds. By leveraging the synergies between modules, the gradient coatings showcase superior antifouling ability, high adhesion strength (≈3.5−9.0 MPa), easy peelability (≈1.5−5.5 N·cm ⁻¹ ), high transparency (>85% transmittance), and recyclability. It is expected to be useful as a temporary or durable antifouling coating in marine applications such as underwater sensors and robots.