Zwitterionic Copolymer-Regulated Interfacial Polymerization for Highly Permselective Nanofiltration Membrane

• Published in: Nano letters 2021-08, Vol.21 (15), p.6525-6532
• Main Authors: Lin, Yuqing, Yao, Xuesong, Shen, Qin, Ueda, Takafumi, Kawabata, Yuki, Segawa, Jumpei, Guan, Kecheng, Istirokhatun, Titik, Song, Qiangqiang, Yoshioka, Tomohisa, Matsuyama, Hideto
• Format: Article
• Language: English
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/acs.nanolett.1c01711

A highly permselective nanofiltration membrane was engineered via zwitterionic copolymer assembly regulated interfacial polymerization (IP). The copolymer was molecularly synthesized using single-step free-radical polymerization between 2-methacryloyloxyethyl phosphorylcholine (MPC) and 2-aminoethyl methacrylate hydrochloride (AEMA) (P­[MPC-co-AEMA]). The dynamic network of P­[MPC-co-AEMA] served as a regulator to precisely control the kinetics of the reaction by decelerating the transport of piperazine toward the water/hexane interface, forming a polyamide (PA) membrane with ultralow thickness of 70 nm, compared to that of the pristine PA (230 nm). Concomitantly, manipulating the phosphate moieties of P­[MPC-co-AEMA] integrated into the PA matrix enabled the formation of ridge-shaped nanofilms with loose internal architecture exhibiting enhanced inner-pore interconnectivity. The resultant P­[MPC-co-AEMA]-incorporated PA membrane exhibited a high water permeance of 15.7 L·m–2·h–1·bar–1 (more than 3-fold higher than that of the pristine PA [4.4 L·m–2·h–1·bar–1]), high divalent salt rejection of 98.3%, and competitive mono-/divalent ion selectivity of 52.9 among the state-of-the-art desalination membranes.