Designing Nanofluidic Diode from a Hybrid‐Bilayer Covalent Organic Framework: Molecular Simulation Investigation

Abstract

Nanofluidic diodes are potentially useful in many important applications such as sensing, electronics, and energy conversion. However, the manufacturing of controllable nanopores for nanofluidic diodes is technically challenging. Herein, a nanofluidic diode is designed from a highly programmatic covalent organic framework (COF). Through molecular simulation, remarkable diode behavior is observed in a hybrid‐bilayer COF but not in its constituent single‐layer COFs. The rectification effect of ion current in the hybrid‐bilayer COF is attributed to an asymmetric electrostatic potential across the COF nanopore. Furthermore, a synergistic effect of counterion is unraveled in the hybrid‐bilayer COF, and the presence of counterion is found to reduce the entry barrier and facilitate ion transport. The performance of the hybrid‐bilayer COF as a nanofluidic diode is comprehensively investigated by varying salt concentration, layer number, interlayer spacing, and slipping. This proof‐of‐concept simulation study demonstrates the feasibility of the hybrid‐bilayer COF as a nanofluidic diode and the finding may stimulate the development of new nanofluidic platforms.

Nanochannel‐Based Ion Transport and Its Application in Osmotic Energy Conversion: A Critical Review

“…Figure 13b demonstrates a nanofluidic system in which a 1 m KCl aqueous solution is separated by different types of COF membranes with sub-nanometer pore sizes. [120] The ionic currents at different electric field intensities across the system (I-V curves) are recorded. A linear I-V relationship emerges in the singlelayer COF, indicating the behavior of electronic resistors without an ionic rectification effect.…”

“…Copyright 2023, American Chemical Society. b) Reproduced with permission [120]. Copyright 2023, Wiley-VCH.…”