2D Copper MOF Membranes with Precise Pores for Ionic Memory

Biological ion channels play a critical role in the complex physiological processes of living organisms. Inspired by these natural systems, we demonstrate the fabrication of ultrathin 2D copper-based metal-organic framework (CuMOF) films and their application to mimic key functionalities of biological membranes. Using a liquid-air interface synthesis technique, we synthesized CuMOF films with tunable thicknesses ranging from 1.4 nm to 20 nm over centimeter-scale areas. These membranes exhibit well-defined nanoporous structures of pore diameter 1.5 nm that facilitate nanofluidic ion transport. The ionic conductance of the CuMOF films strongly depends on both film thickness and electrolyte concentration, demonstrating surface-charge-dominated transport and Na⁺ selective ion conduction at low ionic strengths. Moreover, this selective ion transport enables osmotic energy generation under a concentration gradient. Additionally, the CuMOF films exhibit ionic memristive behavior, including reversible synaptic potentiation and depression, closely resembling synaptic plasticity. This study presents a scalable, tunable platform for developing bioinspired ionic devices with potential applications in selective ion transport, nanofluidic energy harvesting, and neuromorphic computing.