Voltage-Gated Membranes Incorporating Cucurbit[n]uril Molecular Containers for Molecular Nanofiltration

• Published in: Journal of the American Chemical Society 2022-04, Vol.144 (14), p.6483-6492
• Main Authors: Wang, Yue, Liang, Rong-Zu, Jia, Tian-Zhi, Cao, Xue-Li, Wang, Qian, Cao, Jing-Rong, Li, Shuo, Shi, Qixun, Isaacs, Lyle, Sun, Shi-Peng
• Format: Article
• Language: English
• Subjects: Bridged-Ring Compounds - chemistry; Dimerization; Imidazoles - chemistry; Viologens
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/jacs.2c01263

Smart voltage-gated nanofiltration membranes have enormous potential for on-demand and precise separation of similar molecules, which is an essential element of sustainable water purification and resource recovery. However, the existing voltage-gated membranes are hampered by limited selectivity, stability, and scalability due to electroactive monomer dimerization. Here, for the first time, the host–guest recognition properties of cucurbit[7]­uril (CB[7]) are used to protect the viologen derivatives and promote their assembly into the membrane by interfacial polymerization. Viologen functions as a voltage switch, whereas CB[7] complexation prevents its dimerization and improves its redox stability. The inhibited diffusion of the CB[7]-viologen complex enables the precise patterning of the surface structure. The resultant voltage-gated membrane displays 80% improved rejection performance, excellent recovery accuracy for similar molecules, and anti-fouling properties. This work not only provides an innovative strategy for the preparation of voltage-gated smart nanofiltration membranes but also opens up new avenues for ion-selective transmission in water treatment, bionic ion channels, and energy conversion.