Nanofiber-interwoven gel membranes with tunable 3D-interconnected transport channels for efficient CO₂ separation

Mixed matrix membranes (MMMs) capable of breaking the permeability-selectivity trade-off suffer from the inefficient and disconnected bulky transport channels as well as inferior interfacial compatibility between nanomaterials and polymers. Herein, we propose an original photothermal-triggered in-situ gelation approach to elaborate an original class of MMMs, termed nanofiber-interwoven gel membranes (NIGMs) that feature tunable 3D-interconnected ultrafast transport channels and highly-selective CO₂-philic gel for boosting CO₂ separation performance. The key design of NIGMs lies in leveraging dual functions of CNT-interwoven skeleton: (1) serving as a photothermal confined reactor that rapidly triggers in-situ gelation of highly-selective CO₂-philic gel without phase separation-induced interfacial defects to construct defect-free and thickness-controllable NIGMs; (2) functioning as a 3D-interconnected continuous skeleton for providing ultrafast CO₂ transport channels. By orchestrating the distribution and configuration of interwoven nanofibers, the NIGMs possess a boosted CO₂ permeance of 211.0 GPU increased by 1558% over polymeric gel counterparts and an ultrahigh CO₂/N₂ and CO₂/CH₄ selectivity of up to 151 and 47 respectively. Our work offers a paradigm shift in developing advanced MMMs beyond gas separation.