Y-Shaped Fluorinated Metallo-Polyzwitterion from Cobaltocenium: Facile Synthesis and Enhanced Antifouling Performance

A Y-shaped fluorinated metallo-zwitterionic monomer NB-Co⁺-STFSI^– with cobaltocenium as the cationic group and sulfonyl(trifluoromethylsulfonyl) imide anion (STFSI, −SO₂N⁽⁻⁾SO₂CF₃) as the anionic group was synthesized via catalyst-free hydroamination and polymerized via ring-opening metathesis polymerization (ROMP) to give the corresponding fluorinated metallo-polyzwitterion, PNB-Co⁺-STFSI^–. In such a zwitterionic system, the introduction of both the hydrophilic cobaltocenium and hydrophobic fluorocarbon unit of STFSI enables the regulation of hydration properties, leading to distinct solution and surface properties that deviate from those of conventional zwitterionic polyelectrolytes. Although the resulting polymer is water-insoluble, the PNB-Co⁺-STFSI^– coating exhibits strong surface hydrophilicity. Using a simple dip-coating process, the PNB-Co⁺-STFSI^– coatings adhere stably to various substrates and demonstrate exceptional antifouling performance, reducing bacterial adhesion by >95% and suppressing protein adsorption to <5% within 8 h; even after 72 h, protein adsorption remains below 15%. This work not only expands the family of zwitterionic polymers but also opens new avenues for the design of advanced antifouling materials.