Symmetrical Permeable Membranes Consisting of Overlapped Block Copolymer Cylindrical Micelles for Nanoparticle Size Fractionation

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• 作者：Zhuan Yi ; Pei-Bin Zhang ; Cui-Jing Liu ; Li-Ping Zhu
• 刊名：Macromolecules
• 出版年：2016
• 出版时间：May 10, 2016
• 年：2016
• 卷：49
• 期：9
• 页码：3343-3351
• 全文大小：586K
• 年卷期：0
• ISSN：1520-5835

文摘

Free-standing symmetrical porous membranes consisting of uniform cylindrical micelles were prepared from a polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP) diblock copolymer following a process combining self-assembly and nonsolvent-induced phase separation (SNIPS). The fabricated membranes displayed an impressive ultrastructure by the overlapping of the cylindrical micelles throughout the whole membrane profile (∼65 μm). The effects of copolymer molecular weight and membrane-formation condition on membrane morphology were investigated and discussed in detail. It was concluded that the cylindrical micellar membranes could be obtained in a wide window of fabrication conditions as low molecular weight of PS-b-P4VP was used as the raw material. The permeation tests indicated that the water permeability of the symmetrical membranes reached 400 L/(h m² bar) in neutral condition, which was comparable to that of the block copolymer (BCP) isoporous membrane reported in the literature. Significantly, the permeation and separation properties of the symmetrical membranes exhibiting a strongly pH-dependent character as the pH of feed solution varied between 1 and 6. This phenomenon was attributed to the pH-responsive conformational change of P4VP corona in the micellar aggregates of BCP. The potential application of the developed membranes in the size fractionation of nanoparticles with a wide size distribution was demonstrated.