Interlayer-Shifting and Functionalization of 2D COF Membranes for Controlled Transport

2D COF membrane is a versatile platform for the understanding and control of ion/molecular transport with its microporosity, interlayer spacing and rich space of chemistry.<br/> <br/>In the first part of our work, we attempted to regulate the interlayer alignment of 2D COF membranes by the use of different catalyst. In contrast to traditional acid, the Lewis acid is able to accelerate the polymerization of imine-based COF and drives the interlayer shifting between adjacent layers, thereby resulting in pore redistribution and reduced pore size. The membrane exhibits high permeance and reasonable selectivity for H2/CO2 separation.In the 2^nd part of our work, we functionalized the COF with sulfonate groups and observed interesting coordination-facilitated ion transport in the mixed ion environment. While single ion tests do not show much selectivity towards divalent and monovalent ions, the ion transport is much accelerated in the mixed ion solution, enabling high Mg2+/Li+ selectivity.