Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST) , Daejeon 34141, Korea.
J Am Chem Soc. 2017 Feb 15;139(6):2329-2337. doi: 10.1021/jacs.6b11349. Epub 2017 Feb 7.
In spite of the huge research interest, ionic polymers could not have been synthesized in the vapor phase because the monomers of ionic polymers contain nonvolatile ionic salts, preventing the monomers from vaporization. Here, we suggest a new, one-step synthetic pathway to form a series of cross-linked ionic polymers (CIPs) in the vapor phase via initiated chemical vapor deposition (iCVD). 2-(Dimethylamino)ethyl methacrylate (DMAEMA) and 4-vinylbenzyl chloride (VBC) monomers are introduced into the iCVD reactor in the vapor phase to form a copolymer film. Simultaneously in the course of the deposition process, the tertiary amine in DMAEMA and benzylic chloride in VBC undergo a Menshutkin nucleophilic substitution reaction to form an ionic ammonium-chloride complex, forming a highly cross-linked ionic copolymer film of p(DMAEMA-co-VBC). To the best of our knowledge, this is the first report on the synthesis of CIP films in the vapor phase. The newly developed CIP thin film is further applied to the surface modification of the membrane for oil/water separation. With the hydrophilic and underwater oleophobic membrane whose surface is modified with the CIP film, excellent separation efficiency (>99%) and unprecedentedly high permeation flux (average 2.32 × 10 L m h) are achieved.
尽管人们对此研究兴趣浓厚，但离子聚合物无法在气相中合成，因为离子聚合物的单体含有非挥发性的离子盐，阻止了单体的蒸发。在这里，我们提出了一种新的一步法气相合成交联离子聚合物（CIP）的途径，通过引发化学气相沉积（iCVD）。将 2-（二甲氨基）乙基甲基丙烯酸酯（DMAEMA）和 4-乙烯基苄基氯（VBC）单体引入气相 iCVD 反应器中形成共聚物薄膜。同时，在沉积过程中，DMAEMA 中的叔胺和 VBC 中的苄基氯发生 Menshutkin 亲核取代反应，形成离子铵-氯化物络合物，形成高度交联的 p(DMAEMA-co-VBC)离子共聚物薄膜。据我们所知，这是气相合成 CIP 薄膜的首次报道。新开发的 CIP 薄膜进一步应用于膜的表面改性以用于油水分离。具有经 CIP 薄膜改性的亲水水下疏油表面的膜，实现了优异的分离效率（>99%）和前所未有的高渗透通量（平均 2.32×10 L m h）。
