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

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

Automated summary

This study utilizes the host-guest recognition properties of CB[7] to protect viologen derivatives and assemble them into a smart nanofiltration membrane. The resulting membrane shows improved rejection performance, recovery accuracy, and anti-fouling properties.