Upgrading polysulfone ultrafiltration membranes by blending with amphiphilic block copolymers: Beyond surface segregation
Upgrading polysulfone ultrafiltration membranes by blending with amphiphilic block copolymers: Beyond surface segregation
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DOI：
10.1016/j.memsci.2016.01.030
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发表时间：
2016-05-01
影响因子：
9.5
通讯作者：
Wang, Yong
中科院分区：
文献类型：
--
作者：
Chen, Yuqing;Wei, Mingjie;Wang, Yong
两亲性共聚物在相转化过程中的表面分离长期以来被用于改善膜的亲水性。通常，将共聚物作为添加剂稀疏地加入到浇铸溶液中。本文通过增加两亲性共聚物的用量，除了表面分离效应外，还利用共聚物的额外渗透增强效应，获得了性能协同提升的共混超滤膜。我们共混两亲性嵌段共聚物，聚砜-嵌段-聚乙二醇（PSf-b-PEG），与聚砜基础聚合物在不同的百分比高达70%。PSf和PSf-b-PEG之间不存在相容性问题，因为它们在任何共混比下都是可混溶的。红外光谱和X射线光电子能谱证实了PEG块的表面偏析。此外，PSf-b-PEG通过减慢聚合物溶液的沉淀速率而明显影响相分离过程，从而产生具有较厚皮层的膜。有趣的是，增加共聚物的百分比导致在共混物膜中的更多的水可渗透的PEG微区，从而提高水渗透性。共混膜同时表现出提高的渗透性，亲水性，耐污染性，以及性能稳定性。当共聚物含量为40%时，膜的最高渗透率可达400 L/（m（2）h bar），远高于其他文献中制备的聚砜膜。通过与PEG均聚物的比较，我们发现PSf-bPEG共聚物的上级性能除了表面分离的作用外，还源于PEG微区额外的水渗透性。(C)2016爱思唯尔B. V.保留所有权利。
Surface segregation of amphiphilic copolymers in the phase inversion process has long been used to improve membrane hydrophilicity. Typically, the copolymer is sparsely dosed into the casting solutions as additives. Herein we substantially increase the dosages of amphiphilic copolymers, and obtain blend ultrafiltration membranes with synergetically upgraded performances because of extra permeability enhancing effect of the copolymer in addition to the surface segregation effect. We blend amphiphilic block copolymer, polysulfone-block-polyethylene glycol (PSf-b-PEG), with polysulfone base polymer at various percentages up to 70%. There is no compatible issue between the PSf and PSf-b-PEG as they are miscible at any blend ratio. Infrared spectroscopy and X-ray photoelectron spectroscopy confirm the surface segregation of PEG blocks. Moreover, PSf-b-PEG evidently influences the phase separation process by slowing down the precipitation rate of the polymer solutions, thus producing membranes with thicker skin layers. Interestingly, increasing copolymer percentages result in more water-permeable PEG microdomains in the blend membranes and consequently enhanced water permeance. The blend membranes exhibit simultaneously upgraded permeance, hydrophilicity, fouling resistance, and also performance stability. The highest permeance reaches nearly 400 L/(m(2) h bar) at a copolymer percentage of 40%, which is much higher than those of PSf membranes prepared in other works. By comparing with PEG homopolymer, we identify that the superior performances are originated also from the additional water permeability through PEG microdomains in addition to the effect of surface segregation of PSf-bPEG copolymers. (C) 2016 Elsevier B.V. All rights reserved.