Self-Assembly-Mediated Codeposition versus Terminal Anchoring Strategies: Amphiphilic Copolymer Brushes for Sustainable Antifouling

Abstract

The persistent challenge of treating oily wastewater from industrial effluents and environmental spills demands advanced separation materials with sustainable antifouling capabilities. While superwetting interfaces show promise in oil/water separation, the long-term stability and fabrication complexity of functional coatings remain critical limitations. This study presents a systematic comparison of two surface engineering approaches for stainless-steel meshes (SSMs): (1) terminal anchoring of dopamine-end-functionalized amphiphilic copolymers versus (2) self-assembly mediated codeposition of polymer–dopamine complexes. Through controlled integration of zwitterionic moieties and hydrophobic segments, both strategies create hierarchically structured surfaces combining strong hydrophilicity with oil-repellent characteristics. The results reveal that the codeposited PDA–PMB30 coating achieves superior hydration capacity through three-dimensional polymer networking, while the terminally anchored PMBD70 system demonstrates enhanced hydration stability via covalent grafting density optimization. In practical testing, both modified SSMs maintain exceptional separation efficiencies (96% for PDA–PMB30, 93% for PMBD70) through 20 operational cycles, outperforming all other coating systems in durability metrics. The synergistic combination of bioinspired adhesion mechanisms and amphiphilic balance endows these meshes with unique antifouling resilience, showing >96% separation efficiencies and stable performance in high salinity (1 M NaCl), strong acidity (pH = 1), and strong alkalinity (pH = 14) environments. This work establishes fundamental structure–property relationships between surface grafting architectures and separation performance, providing actionable insights for designing robust oil/water separation systems for petrochemical wastewater treatment and marine spill remediation.