Durable superhydrophilic coatings formed for anti-biofouling and oil–water separation

• PCTE membrane with superhydrophilic coating was prepared for oil–water separation.
• Superhydrophilic coating showed enhanced stability and anti-biofouling properties.
• More than 99.5% oil–water separation efficiency was obtained by modified membrane.
• Pore size of membrane can be controlled for future oil–water emulsion separation.

Building up unique interfaces by means of layer-by-layer (LbL) assembly is of interest for a variety of practical applications, particularly those that require the advantages of special wettability. Herein, a UV-cured superhydrophilic coating with high stability was constructed in the form of a hydrogen-bonding-based LbL multilayer incorporating silica nanoparticles (SNPs). In our present work, hydrophilic branched poly(ethylenimine) (BPEI) and SNPs were assembled into LbL multilayers in the presence of UV-curable poly(urethane acrylate) (PUA), which is described herein as (PUA–SNPs/BPEI)n. The as-prepared architectures showed good acid, thermal, and mechanical stability following crosslinking by UV exposure. Crosslinking is of great importance for LbL film, considering the weak interactions among polyelectrolytes. Owing to the superhydrophilicity of the coating, the anti-biofouling properties were enhanced to some extent for gram-positive Staphylococcus aureus and gram-negative Pseudomonas aeruginosa contamination. Furthermore, the superhydrophilic polycarbonate track-etched (PCTE) membrane coated with (PUA–SNPs/BPEI)n coatings with different numbers of LbL deposition cycles were also investigated for oil–water separation. To the best of our knowledge, this is the first demonstration of rough structures created on a straight pore PCTE membrane. Commercial PCTE membranes with robust coatings, which allow water to penetrate the membrane while oily substance are intercepted, have been developed for regular oil–water separation with more than 99% efficiency.

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