Block copolymer ultrafiltration membranes by spray coating coupled with selective swelling
Block copolymer ultrafiltration membranes by spray coating coupled with selective swelling
复制标题
喷涂结合选择性溶胀的嵌段共聚物超滤膜
DOI：
10.1016/j.memsci.2019.117656
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发表时间：
2020-03-15
影响因子：
9.5
通讯作者：
Wang, Yong
中科院分区：
文献类型：
--
作者：
Ma, Dongwei;Zhou, Jiemei;Wang, Yong
嵌段共聚物（bcp）已被证明是制备具有良好孔隙度的超滤膜的前驱体。为了最大限度地提高BCP的分离性能，BCP通常以薄膜复合膜的形式使用，在大孔基底的顶部有纳米孔BCP分离层。然而，如何高效、可控地制备这种复合材料结构仍然是一个挑战。在此，我们证明了在大孔基底上喷涂BCP溶液然后选择性膨胀是一种简单且高度可控的制备BCP复合膜的策略。首先，将BCP溶液喷涂在大孔尼龙支架上。通过改变聚合物浓度和不同的喷涂条件，获得了无缺陷、均匀致密的BCP层。通过改变喷涂的步宽，可以将BCP层的厚度控制在几微米的范围内。在喷涂过程中，既不需要预先填充大孔支架以防止溶液渗透，也不需要后处理以加强两层的附着力。然后将BCP包覆的载体浸泡在热乙醇中，在BCP层中形成纳米孔隙，遵循选择性膨胀诱导孔隙生成的机制。由此制备的复合膜具有优异的超滤性能。同时，通过改变膨胀条件，可以方便地调节膜的孔径、表面亲水性和分离性能。我们期望这种喷雾涂层加上选择性膨胀可以大规模生产bcp基复合膜，用于工业生产。
Block copolymers (BCPs) have been demonstrated to be promising precursors in the fabrication of ultrafiltration membranes with well-defined porosities. To maximize the separation performance, BCPs are usually used in the forms of thin-film composite membranes with nanoporous BCP separation layers on the top of macroporous substrates. However, it remains a challenge to prepare such composite structures in an efficient and controllable way. Herein, we demonstrate that spray coating of BCP solutions on macroporous substrates followed by selective swelling is a facile and highly controllable strategy to produce BCP composite membranes. First, the BCP solution was spray-coated on a macroporous nylon support. By changing polymer concentrations as well as various spray conditions, a defect-free and uniform dense BCP layer was obtained. The thickness of the BCP layer can be controlled within the scope of a few micrometers simply by altering the step width of spray coating. Neither pre-filling of the macroporous supports to prevent solution permeation nor post-treatment to strengthen the adhesion of the two layers is required during the spray coating process. The BCP-coated support was then soaked in hot ethanol to create nanoporosity in the BCP layer following the mechanism of selective swelling-induced pore generation. Thus-produced composite membranes exhibit excellent ultrafiltration performances. Meanwhile, the pore sizes, surface hydrophilicity and consequently separation performances of the membranes can be conveniently tuned by changing swelling conditions. We expect this spray coating coupled with selective swelling to produce BCP-based composite membranes at large scale for industrial production.