Mass Transport via In-Plane Nanopores in Graphene Oxide Membranes
Résumé
Ångstrom-confined solvents in 2-d laminates can travel through interlayer spacings, gaps between adjacent sheets, and via in-plane pores. Among these, experimental access to investigate the mass transport through in-plane pores is lacking. Our experiments allow understanding of this mass transport via controlled variation of oxygen functionalities, size and density of in-plane pores in graphene oxide membranes. Contrary to expectations, our transport experiments show that higher in-plane pore densities may not necessarily lead to higher water permeability. We observed that membranes with a high in-plane pore density, but low oxygen functionalities exhibit a complete blockage of water. However, upon using water-ethanol mixtures with a weaker hydrogen network, these membranes show an enhanced permeation. Our combined experimental and computational results suggest that the transport mechanism is governed by the attraction of the solvents towards the pores with functional groups and hindered by the strong hydrogen network of water formed under Ångstrom confinement.