Asymmetric ionic covalent organic framework membranes with tunable Turing patterns prepared via ion regulated strategy
Jingcheng Du, Jian Guan, Ali A. AL-Thuraya, Weiwang Lim, Qian Sun, Ayan Yao, Dong Cao, Ji Ma, Yuting Zhang, Yumo Fan, Pengjia Dou, Jiangtao Liu
Abstract
Advanced self-standing ionic covalent organic framework membranes (ICOFM) with strong mechanical property and high crystallinity are crucial for expanding the applications of COF membrane, yet it remains a significant challenge. Furthermore, ICOFM, which are often fragile and brittle, typically suffer from trade-off limitation between mechanical strength and high crystallinity, limiting their potential in realms such as separation processes, flexible electronics, and optoelectronics. In this work, a synthetic methodology based on an inorganic ion strategy, a previously underexplored approach, is conceived to prepare hypercrystalline and highly durable ICOFM through electrostatic-assisted interfacial monomers aggregation with enhanced diffusion, reactivity and competitive coordination regulation, fulfilling suitable reaction-diffusion conditions for Turing architecture. The effects of four category inorganic ions, containing (ⅰ) strong acid ions, (ⅱ) weak acid ions, (ⅲ) non-metallic salt ions and (ⅳ) metal cations, on the interfacial polymerization (IP) system are systematically studied through MD simulation, DFT calculation and experimental results. The resulting ICOFM, carrying tunable Turing patterns, demonstrate exceptional mechanical property, asymmetric fluid transport, and molecular sieve capability. These advances will promote future developments in the structural design, efficient synthesis, and high-end applications of COF membrane by reasonably manipulating ion types, offering promising prospects for the advancement of membrane-based technologies.