Aperture-in-Interlayer Engineering of 2D Graphene Oxide Nanochannels via Structural Locking and Macrocyclic Cavity Reorganization

Abstract

Selective transport in nanoconfined channels depends not only on channel size, but also on the dynamic stability and local physicochemical environment of the transport pathway under operation. In two-dimensional (2D) graphene oxide (GO) membranes, however, hydration-induced swelling and pressure-driven laminar deformation often destabilize the interlayer spaces, limiting precise water/salt separation. Here, we report a hierarchical nanochannel aperture-in-interlayer engineering strategy that integrates structural locking of GO laminates with macrocyclic cavity-mediated microenvironment reorganization. Controlled chemical conversion suppresses interlayer swelling and stabilizes the operative slit-like channels, thereby enhancing channel integrity and sieving capability. Subsequent participation of macrocycles introduces a localized cavity-bearing transport regulator into the locked interlayer channels, partially reconstructing the confined transport topology and tailoring local interactions with water molecules and ions. This slit-cavity coupled architecture differentiates water and salt transport by balancing channel confinement, cavity accessibility, and interfacial microenvironment. Among the macrocycles examined, the optimum matched cavity shows the best overall separation performance, with Na2SO4 and NaCl rejections of ∼99.8% and ∼95%, respectively. More broadly, this work establishes a general route for reorganizing transport in 2D laminar membranes through the integration of structural stabilization and molecular cavity regulation.