Manipulating central intermolecular interaction in confined nanochannels for fast transport

Abstract

The study of molecule transport within confined nanochannels is crucial to developing high-performance membranes. Previous studies mainly focus on the interfacial molecule transport; however, the central molecule transport, equally crucial, has been disregarded. Herein, vertically aligned vermiculite-based (Vr-based) membranes with long-range nanochannels are engineered to ensure a stable flow. Meanwhile, the channel surfaces are functionalized (–CH₃, –NH₂, and –CF₃ groups) to tune the interaction with interfacial molecules, thus affecting the intermolecular interaction of central molecules. We demonstrate that strong channel-molecule interaction between polar walls and protonic solvents can impede the formation of hydrogen-bond networks in central molecules, thus reducing the central intermolecular interaction and enabling fast transport. For instance, the Vr-CF₃ membrane displays a 69% improvement in water permeance in comparison to the Vr-CH₃ membrane, achieving 13.0 LMH bar⁻¹. Nevertheless, nonpolar walls with weak channel-molecule interaction show uninfluenced intermolecular interaction, giving comparable transport ability for both protonic and non-protonic solvents.