Engineering Tunable Macrocyclic Subnanometer Pores as Biomimetic Channels for Ångstrom-Precision Separation

Efficient and selective membranes are essential for advancing sustainable water treatment processes, with the potential to address the separation of problematic contaminants and reduce environmental waste. The present landscape of conventional membrane fabrication techniques falls short in achieving the required solute-solute selectivity at the molecular level. Traditional approaches, such as interfacial polymerization for thin-film composite (TFC) membranes, were developed to enhance water-solute selectivity but lack precise control over local pore structures and chemical properties.<br/>Herein we demonstrate by using triangular macrocyclic hosts as biomimetic channels, offering a remarkable degree of tunability. By merely substituting the bridging groups, we can directly influence local pore size and structure, resulting in enhanced selectivity and efficiency. This innovation offers the possibility of a bottom-up approach to membrane fabrication that can be customized for specific separation needs, providing an array of advantages. These include precise control over sub-nanometer pore structures, size, and chemical environments through subcomponent modifications, excellent processability, and simplified assembly of subcomponents, thus offering a promising solution for advanced membrane fabrication.