Achieving high permeability and enhanced selectivity for Angstrom-scale separations using artificial water channel membranes

• Published in: Nature communications Vol. 9; no. 1; pp. 2294 - 11
• Main Authors: Shen, Yue-xiao, Song, Woochul, Barden, D. Ryan, Ren, Tingwei, Lang, Chao, Feroz, Hasin, Henderson, Codey B., Saboe, Patrick O., Tsai, Daniel, Yan, Hengjing, Butler, Peter J., Bazan, Guillermo C., Phillip, William A., Hickey, Robert J., Cremer, Paul S., Vashisth, Harish, Kumar, Manish
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 12.06.2018; Nature Publishing Group; Nature Portfolio
• Subjects: 140/146; 147/135; 147/28; 639/301/357/1018; 639/301/357/341; 639/638/541/966; Aquaporins; Aquaporins - chemistry; Biological membranes; Block copolymers; Channel pores; Computer Simulation; Detergents - chemistry; Energy efficiency; Humanities and Social Sciences; Lipid Bilayers - chemistry; Liposomes - chemistry; Membrane permeability; Membranes; Membranes, Artificial; Microscopy, Confocal; Microscopy, Electron, Transmission; Molecular chains; Molecular Dynamics Simulation; Molecular Weight; multidisciplinary; Permeability; Polymers; Polymers - chemistry; Pore size; Porosity; Salts - chemistry; Science; Science (multidisciplinary); Selectivity; Tradeoffs; Water - chemistry
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-018-04604-y

Synthetic polymer membranes, critical to diverse energy-efficient separations, are subject to permeability-selectivity trade-offs that decrease their overall efficacy. These trade-offs are due to structural variations (e.g., broad pore size distributions) in both nonporous membranes used for Angstrom-scale separations and porous membranes used for nano to micron-scale separations. Biological membranes utilize well-defined Angstrom-scale pores to provide exceptional transport properties and can be used as inspiration to overcome this trade-off. Here, we present a comprehensive demonstration of such a bioinspired approach based on pillar[5]arene artificial water channels, resulting in artificial water channel-based block copolymer membranes. These membranes have a sharp selectivity profile with a molecular weight cutoff of ~ 500 Da, a size range challenging to achieve with current membranes, while achieving a large improvement in permeability (~65 L m −2  h −1  bar −1  compared with 4–7 L m −2  h −1  bar −1 ) over similarly rated commercial membranes. Synthetic polymeric membranes used for separations suffer from permeability-selectivity trade-offs. Here the authors demonstrate how a bioinspired pillar[5]arene artificial water channel embedded in a copolymer membrane can improve selectivity while still achieving high permeability.