Lehrstuhl für Technische Chemie II, Universität Duisburg-Essen , 45117 Essen, Germany.
Center for Nanointegration Duisburg-Essen , 47057 Duisburg, Germany.
ACS Appl Mater Interfaces. 2016 Oct 26;8(42):29001-29014. doi: 10.1021/acsami.6b09369. Epub 2016 Oct 11.
Stimuli-responsive membranes that can adjust mass transfer and interfacial properties "on demand" have drawn large interest over the last few decades. Here, we designed and prepared a novel magnetoresponsive separation membrane with remote switchable molecular sieving effect by simple one-step and scalable nonsolvent induced phase separation (NIPS) process. Specifically, poly(ether sulfone) (PES) as matrix for an anisotropic membrane, prefabricated poly(N-isopropylacrylamide) (PNIPAAm) nanogel (NG) particles as functional gates, and iron oxide magnetic nanoparticles (MNP) as localized heaters were combined in a synergistic way. Before membrane casting, the properties of the building blocks, including swelling property and size distribution for NG, and magnetic property and heating efficiency for MNP, were investigated. Further, to identify optimal film casting conditions for membrane preparation by NIPS, in-depth rheological study of the effects of composition and temperature on blend dope solutions was performed. At last, a composite membrane with 10% MNP and 10% NG blended in a porous PES matrix was obtained, which showed a large, reversible, and stable magneto-responsivity. It had 9 times higher water permeability at the "on" state of alternating magnetic field (AMF) than at the "off"-state. Moreover, the molecular weight cutoff of such membrane could be reversibly shifted from ∼70 to 1750 kDa by switching off or on the external AMF, as demonstrated in dextran ultrafiltration tests. Overall, it has been proved that the molecular sieving performance of the novel mixed matrix composite membrane can be controlled by the swollen/shrunken state of PNIPAAm NG embedded in the nanoporous barrier layer of a PES-based anisotropic porous matrix, via the heat generation of nearby MNP. And the structure of such membrane can be tailored by the NIPS process conditions. Such membrane has potential as enabling material for remote-controlled drug release systems or devices for tunable fractionations of biomacromolecule/-particle mixtures.
在过去的几十年中，能够“按需”调节传质和界面性质的响应性膜引起了人们的极大兴趣。在这里，我们通过简单的一步法和可扩展的非溶剂致相分离（NIPS）工艺设计并制备了一种具有远程开关分子筛效应的新型磁响应分离膜。具体而言，将具有各向异性的膜用聚醚砜（PES）作为基质，将预制的聚（N-异丙基丙烯酰胺）（PNIPAAm）纳米凝胶（NG）颗粒作为功能门，将氧化铁磁性纳米颗粒（MNP）作为局部加热器以协同方式组合在一起。在膜铸造之前，研究了构建块的性能，包括 NG 的溶胀性能和粒径分布，以及 MNP 的磁性和加热效率。此外，为了通过 NIPS 确定用于膜制备的最佳膜铸造条件，对组成和温度对共混纺丝溶液的影响进行了深入的流变学研究。最后，获得了一种在多孔 PES 基质中混合 10%的 MNP 和 10%的 NG 的复合膜，该复合膜表现出大、可逆和稳定的磁响应性。在交变磁场（AMF）的“开”状态下，其水透过率比“关”状态下高 9 倍。此外，通过关闭或打开外部 AMF，这种膜的分子量截止值可以从约 70 到 1750 kDa 可逆切换，在葡聚糖超滤测试中得到了证明。总的来说，已经证明了新型混合基质复合膜的分子筛性能可以通过嵌入基于 PES 的各向异性多孔基质的纳米多孔阻隔层中的 PNIPAAm NG 的溶胀/收缩状态来控制，通过附近 MNP 的发热来实现。并且可以通过 NIPS 工艺条件来调整这种膜的结构。这种膜有望成为用于远程控制药物释放系统或用于生物大分子/颗粒混合物可调分级的设备的有效材料。
