Co-Casting Highly Selective Dual-Layer Membranes with Disordered Block Polymer Selective Layers
Co-Casting Highly Selective Dual-Layer Membranes with Disordered Block Polymer Selective Layers
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DOI：
10.1021/acsami.0c13726
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发表时间：
2020-10-07
影响因子：
9.5
通讯作者：
Hillmyer, Marc A.
中科院分区：
文献类型：
--
作者：
Hampu, Nicholas;Werber, Jay R.;Hillmyer, Marc A.
采用共铸技术制备了具有高选择性和透水性的双层超滤膜，该超滤膜由无序的聚（甲基丙烯酸甲酯-静态-苯乙烯）-嵌段-聚（丙交酯）选择层和聚砜（PSF）支撑层组成。将二嵌段聚合物的稀溶液旋涂到溶剂溶胀的PSF层上，快速加热以干燥和无序化嵌段聚合物层，随后浸入冰水凝固浴中以动力学捕获嵌段聚合物选择性层中的无序状态并通过非溶剂诱导的相分离沉淀支撑层。随后除去聚丙交酯块，产生适用于UF的多孔膜。这些双层膜的渗透性通过调节PSF铸膜溶液的浓度来调节，同时由于自组装嵌段聚合物选择性层的窄孔径分布而保持尺寸选择性。热退火步骤的消除导致水渗透性的显著增加，而不会不利地影响尺寸选择性，因为浓缩的浇铸溶液中存在的无序纳米结构在快速干燥时被动力学捕获。在这项工作中概述的共铸策略可以使具有高渗透性和高选择性的嵌段聚合物膜的可扩展制造。
Highly selective and water permeable dual-layer ultrafiltration (UF) membranes comprising a disordered poly(methyl methacrylate-stat-styrene)-block-poly(lactide) selective layer and a polysulfone (PSF) support layer were fabricated using a co-casting technique. A dilute solution of diblock polymer was spin coated onto a solvent-swollen PSF layer, rapidly heated to dry and disorder the block polymer layer, and subsequently immersed into an ice water coagulation bath to kinetically trap the disordered state in the block polymer selective layer and precipitate the support layer by nonsolvent-induced phase separation. Subsequent removal of the polylactide block generated porous membranes suitable for UF. The permeability of these dual-layer membranes was modulated by tuning the concentration of the PSF casting solution, while the size-selectivity was maintained because of the narrow pore size distribution of the self-assembled block polymer selective layer. Elimination of the thermal annealing step resulted in a dramatic increase in the water permeability without adversely impacting the size-selectivity, as the disordered nanostructure present in the concentrated casting solution was kinetically trapped upon rapid drying. The co-casting strategy outlined in this work may enable the scalable fabrication of block polymer membranes with both high permeability and high selectivity.