Metal ions ‘sewing’ isoporous membranes with polystyrene-block-poly (acrylic acid) block copolymer

As a representative amphiphilic block copolymer, polystyrene-block-poly (acrylic acid) (PS-b-PAA) has great potential in biomedical applications owing to its pH-responsiveness, antibacterial property and biocompatibility. Self-assembly of PS-b-PAA has been widely investigated with regard to micelles and thin films. Whereas, it is difficult to precipitate PS-b-PAA in water to make membrane due to the high hydrophilicity of PAA blocks. Herein, a process is described to fabricate PS-b-PAA isoporous membranes by combining self-assembly of metal-block copolymer complexes and non-solvent induced phase separation. Different antibacterial metal ions were doped in PS-b-PAA casting solution, which not only enhanced the mechanical property significantly, but also adjusted the pore size of the membranes. The membranes exhibited a pH-responsive release property and excellent separation performance based on size or charge differences. Moreover, the antifouling property was significantly enhanced through the synergistic effect of antibacterial metal ions and PAA segments.