Breaking The Permeance-Selectivity Tradeoff for Post-Combustion Carbon Capture: A Bio-Inspired Strategy to Form Ultrathin Hollow Fiber Membranes.

Thin film composite (TFC) hollow fiber membranes with ultrathin selective layer are desirable to maximize the gas permeance for practical applications. Herein we propose a bio-inspired strategy to fabricate sub-100-nm membranes via a tree-mimicking polymer network, term as PDMS-PEG, with amphipathic components featuring multi-functionalities. The hydrophobic polydimethylsiloxane (PDMS) brushes act as the roots that can strongly cling to the gutter layer, the PDMS crosslinkers function as the xylems to enable fast gas transport, and the hydrophilic ethylene-oxide moieties (brushes and mobile molecules) resemble tree leaves that selectively attract CO 2 molecules. As a result, a ∼ 27 nm-thick PDMS-PEG selective layer can be attached onto the hollow fiber supported PDMS gutter layer through simple dip-coating method without any modification. Furthermore, a CO 2 permeance of ∼ 2700 GPU and a CO 2 /N 2 selectivity of ∼ 21 that is beyond the permeance-selectivity upper bound for hollow fiber membranes is achieved. Our bio-inspired concept can potentially open the possibility of scalable hollow fiber membranes production for commercial applications in post-combustion carbon capture and beyond. This article is protected by copyright. All rights reserved.