Mochou Liu,Huixia Xu,Limei Liu,Xia Han,Honglai Liu
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.
Poly(N-isopropylacrylamide) (PNIPAM) chain with catechol end group was designed and successfully synthesized by a reversible addition–fragmentation chain transfer (RAFT) procedure, and then, even via a simple one-step soaking method, it could be firmly grafted to many different substrates (e.g., a stainless-steel mesh, a nylon microfiltration membrane, an Al plate, and glass). Moreover, after the end anchoring, the formed thin and uniform coating of PNIPAM onto the surfaces of the stainless-steel mesh and the nylon microfiltration membrane would endow the surfaces with a valuable thermo-driven controllable separation ability for oil–water mixtures and emulsions, respectively. And below PNIPAM’s lower critical solution temperature (LCST) (34 °C), the membranes exhibited hydrophilicity and underwater oleophobicity and thus can be used for the separation of a “light oil”/water mixture and an O/W emulsion through a “removing water” process; meanwhile, above its LCST, the membranes show the opposite properties (hydrophobicity and oleophilicity) and thus are used to separate a “heavy oil”/water mixture and a W/O emulsion through a “removing oil” process. In addition, without changing the morphologies and pore sizes of the substrates, the membranes gave many excellent performances such as excellent recyclability, high separation efficiency and a thermo-driven controllable separation ability. So, the facile and effective strategy presented in this work that is suitable for the coupling of PNIPAM with various substrates would also supply an inspiration to the effect conjunction for heterogeneous materials of other functional polymers and substrates.
危险品化学品经营许可证（带存储）