Side-Chain-Dependent Functional Intercalations in Graphene Oxide Membranes for Selective Water and Ion Transport

Subnanometer interlayer space in graphene oxide (GO)laminatesis desirable for use as permselective membrane nanochannels. Althoughthe facile modification of the local structure of GO enables variousnanochannel functionalizations, precisely controlling nanochannelspace is still a challenge, and the roles of confined nanochannelchemistry in selective water/ion separation have not been clearlydefined. In this study, macrocyclic molecules with consistent basalplane but varying side groups were used to conjunct with GO for modifiednanochannels in laminates. We demonstrated the side-group dependenceof both the angstrom-precision tunability for channel free space andthe energy barrier setting for ion transport, which challenges thepermeability-selectivity trade-off with a slightly decreasedpermeance from 1.1 to 0.9 L m(-2) h(-1) bar(-1) but an increased salt rejection from 85%to 95%. This study provides insights into the functional-group-dependentintercalation modifications of GO laminates for understanding laminatestructural control and nanochannel design.

Automated summary

Subnanometer interlayer space in graphene oxide (GO) laminates is important for permselective membrane nanochannels. The precise control of nanochannel space and the role of confined nanochannel chemistry in selective water/ion separation are still challenging. This study used macrocyclic molecules with consistent basal plane but varying side groups to modify nanochannels in GO laminates, and demonstrated the side-group dependence of angstrom-precision tunability for channel free space and the energy barrier setting for ion transport. The study provides insights into functional-group-dependent intercalation modifications of GO laminates for structural control and nanochannel design.