具有定制功能的共价有机框架（COF）膜在各种应用中有着巨大的前景，但实现其高度有序孔结构优势的关键是膜制造方法的发展。
该文中，研究人员报道了一种电位差调制的双相策略，用于在环境条件下制备大面积的自支撑COF膜。在极化水/1,2-二氯乙烷（水/DCE）界面上进行制造，其中HCl溶解在水中作为催化剂，并向DCE中添加单体（胺和醛）。通过循环伏安法对水/DCE界面进行外极化，可以连续地将H+从水中泵入DCE，从而促进单体的希夫碱反应和COF膜的生长。
此外，通过界面双电层电容测量可以实时监测COF膜的生长过程，通过非均相离子转移伏安法可以原位检测COF膜的渗透性。由于水/DCE界面上的电位差也可以通过在两相中溶解适当的电解质离子来轻松调节，因此可以在烧杯中制备大面积COF膜。利用该策略和不同的单体，制备了三种具有可调孔径和表面功能性的厘米级独立式COF膜，并通过分子渗透和超滤实验验证了其无缺陷结构。
该双相策略为制备COF膜提供了一种可控且可扩展的方法，并为开发具有独特功能的新型自支撑膜提供了思路。
附：英文原文
Title: Potential Difference-Modulated Synthesis of Self-Standing Covalent Organic Framework Membranes at Liquid/Liquid Interfaces
Author: Rongjie Yang, Shanshan Liu, Qi Sun, Qiaobo Liao, Kai Xi, Bin Su
Issue&Volume: June 22, 2022
Abstract: Covalent organic framework (COF) membranes with tailored functionalities hold great promise in diverse applications, but the key to realize their full advantages of highly ordered pore structures is the development of membrane fabrication approaches. In this work, we report a potential difference-modulated biphasic strategy to fabricate large-area, self-standing COF membranes under ambient conditions. The fabrication was conducted at the polarized water/1,2-dichloroethane (water/DCE) interface, where HCl was dissolved in water as a catalyst and monomers (both amine and aldehyde) were added to DCE. The external polarization of the water/DCE interface by cyclic voltammetry can continuously pump H+ from water to DCE to boost the Schiff base reaction of monomers and the growth of COF membranes. Moreover, the growth process can be real-time-monitored by interfacial double-layer capacitance measurement, and the permeability of COF membranes can be in situ-examined by heterogeneous ion transfer voltammetry. Given that the potential difference across the water/DCE interface can be also facilely modulated by dissolving proper electrolyte ions in two phases, the fabrication of large-area COF membranes is made possible in beakers. Using this strategy and different monomers, three types of centimeter-scale, free-standing COF membranes with tunable pore size and surface functionality were prepared, and their defect-free structure was proved by the molecular permeance and ultrafiltration test. We believe that this biphasic strategy offers a controllable and scalable way to fabricate COF membranes and sheds light on development of novel self-supporting membranes with unique functions.
DOI: 10.1021/jacs.2c03864
Source: https://pubs.acs.org/doi/10.1021/jacs.2c03864
