Controlling assembly behaviors of laminar GO membranes in organic solvents by altering GO-solvent interactions

Two-dimensional graphene oxide (GO) membranes are promising for molecular-scale separations. Laminar GO membranes usually involve liquid phase fabrications in aqueous solvents, whereas their assembly behaviors in organic solvents remain unexplored. Herein, we report a simple methodology for controlling assembly behaviors of laminar GO membranes in organic solvents by altering GO-solvent interactions. We experimentally and theoretically demonstrated that, governed by the competition between GO-solvent intermolecular interaction and GO intramolecular interaction, GO nanosheets displayed deverse disperse properties in different organic solvents, thereby determining their distinct assembly behaviors. Moreover, the membrane formation and structure and their relations to transport properties were studied through detailed investigations of laminar GO membranes assembled in selected organic solvents. The uniform and intact GO membranes built up by good solvents assistant assembly featured competitive organic solvent nanofiltration (OSN) performances. For example, the GODMSO membrane exhibited permeance of 66–76 L m−2 h−1 bar−1 of methanol and rejection of more than 95% of dyes with molecular weights >600 g mol−1, and the GODMF membrane achieved permeance of 26–32 L m−2 h−1 bar−1 of methanol and rejection of more than 95% of dyes with molecular weights >400 g mol−1. This work elucidates the property-structure-performance relationships of laminar GO membranes assembled in organic solvents, offering a straightforward paradigm for controllable assembly of laminar 2D-material membranes via facile solvents selection.