Influence of Solvent Affinity on Transport through Cross-Linked Copolymer Membranes for Organic Solvent Nanofiltration
Influence of Solvent Affinity on Transport through Cross-Linked Copolymer Membranes for Organic Solvent Nanofiltration
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DOI：
10.1021/acsapm.3c00460
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发表时间：
2023-08
影响因子：
5
通讯作者：
M. Dugas;Shukun Zhong;Bumjun Park;Jizhou Jiang;J. A. Ouimet;Jialing Xu;J. Schaefer;W. Phillip
中科院分区：
文献类型：
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作者：
M. Dugas;Shukun Zhong;Bumjun Park;Jizhou Jiang;J. A. Ouimet;Jialing Xu;J. Schaefer;W. Phillip
基于微相分离共聚物的膜提供了解决可用于有机溶剂基过滤的弹性材料的需求的机会。具体地，可以选择共聚物重复单元化学，以赋予溶剂相容性，定制膜纳米结构，并使合成后改性成为可能。在这项研究中，一个聚（三氟乙基甲基丙烯酸酯-co-寡（乙二醇）甲基醚甲基丙烯酸酯-co-甲基丙烯酸缩水甘油酯）[P（TFEMA-OEGMA-GMA）]共聚物的合成和制造成平板和中空纤维膜使用非溶剂诱导相分离铸造技术。GMA重复单元具有环氧基团，其用于通过与从二氨基乙烷到二氨基辛烷的二胺的开环反应来交联共聚物。在水、甲醇、乙醇、四氢呋喃、二甲基甲酰胺和甲苯中的传输实验表明，膜与较长的二胺如二氨基己烷反应，得到稳定的膜。相反，膜与较短的二胺反应，在暴露于有机溶剂时降解。由于它们在有机溶剂中的稳定性，通过二氨基己烷官能化的膜的传输，其特征在于更详细地使用水力渗透性和中性溶质截留实验。这些实验的结果沿着体积溶胀和小角X-射线散射（SAXS）分析揭示了组成共聚物域的溶剂亲和力在确定渗透途径中是关键的。对于P（TFEMA-OEGMA-GMA）膜在质子溶剂，如乙醇，通过OEGMA的亲水性侧链的运输是有利的，而在非质子溶剂，如甲苯，通过疏水性基质的运输占主导地位的膜。在中性溶质排斥实验中，2000克摩尔-1聚丙二醇分子（溶剂化大小<$2 nm）渗透通过疏水域不受阻碍，但完全拒绝时，发生渗透通过亲水区域。这些差异突出了需要了解的共聚物域和溶剂之间的相互作用时，开发的有机溶剂过滤的溶剂弹性膜。
Membranes based on microphase-separated copolymers offer an opportunity to address the need for resilient materials that can be used in organic solvent-based filtration. Specifically, copolymer repeat unit chemistries can be chosen to impart solvent compatibility, to tailor membrane nanostructure, and to enable postsynthetic modification. In this study, a poly(trifluoroethyl methacrylate-co-oligo(ethylene glycol) methyl ether methacrylate-co-glycidyl methacrylate) [P(TFEMA-OEGMA-GMA)] copolymer was synthesized and fabricated into flat sheet and hollow fiber membranes using a non-solvent-induced phase separation casting technique. The GMA repeat units possess epoxide groups that were used to cross-link the copolymer through a ring-opening reaction with diamines ranging from diaminoethane to diaminooctane. Transport experiments in water, methanol, ethanol, tetrahydrofuran, dimethylformamide, and toluene demonstrated that films reacted with longer diamines, such as diaminohexane, result in stable membranes. Conversely, the films reacted with shorter diamines degraded upon exposure to organic solvents. Because of their stability in organic solvents, transport through the diaminohexane-functionalized membranes was characterized in more detail using hydraulic permeability and neutral solute rejection experiments. The results of these experiments along with volumetric swelling and small-angle X-ray scattering (SAXS) analysis revealed that the solvent affinity for the constituent copolymer domains is critical in determining the permeation pathway. For P(TFEMA-OEGMA-GMA) membranes in protic solvents, such as ethanol, transport through the hydrophilic side chains of OEGMA was favored, while for membranes in aprotic solvents, such as toluene, transport through the hydrophobic matrix dominated. In neutral solute rejection experiments, 2000 g mol–1polypropylene glycol molecules (solvated size ∼2 nm) permeated through the hydrophobic domain unhindered but were fully rejected when permeation occurred through the hydrophilic region. These differences highlight the need to understand the interactions between the copolymer domains and solvent when solvent-resilient membranes are developed for organic solvent filtration.