▎ 摘　　要

Graphene oxide (GO) is a unique 2D material that can form nanochannels between adjacent nanosheets, and has attracted concentrated interests in the field of molecule sieving. However, the size of the nanochannels is fixed and hard to change, which is undesirable when using GO-based membranes for separation. Herein, a strategy for controllable adjusting the microstructure of GO nanosheets and size of nanochannels by grafting polydopamine (PDA) on GO is reported. A series of PDA-g-GO composite membranes with different PDA loading are successfully fabricated by simple vacuum filtration. The composite membranes are used to separate 70 wt% ethanol-H2O mixture and 70 wt% isopropyl alcohol-H2O mixture by pervaporation, respectively. The results demonstrate that by grafting PDA on GO, the size of nanochannels can be adjusted effectively. Compared with the original GO membrane, the PDA-g-GO composite membranes show markedly different separation performance. This strategy may significantly extend the applications of GO membranes with fine-tuned nanochannels in various separation fields.