Emerging innovations in rubbery polymeric membranes for CO2 separation: A review

Abstract

Membrane separation technology is gaining increasing prominence, particularly for CO₂ removal in natural gas upgrading and flue gas treatment. Rubbery polymers feature soft, flexible segments that allow unrestricted rotation around the main chain, exhibit molecular flexibility that increases fractional free volume, leading to enhanced gas permeability. This review provides a comprehensive summary of recent innovations in state-of-the-art rubbery polymers for high-performance CO₂ separation membranes, which are advancing this technology toward its theoretical limits, with a focus on developments over the past five years. It emphasizes polymer modifications such as blending, cross-linking, and surface functionalization. Although these strategies remain underexplored, promising results have emerged in CO₂-selective mixed matrix membranes incorporating fillers such as Zeolitic Imidazolate Frameworks (ZIFs), University of Oslo (UiOs), Materials of Institute Lavoisier (MILs), emerging MOF-based and 2D fillers. The common challenges associated with 2D and 3D-based fillers have been systematically summarized. Additionally, the scalability of these technologies from flat sheet to thin film composite hollow fiber membranes which provides energy efficiency suitable for large-scale integration have been discussed. In conclusion, this review identifies key research gaps and future directions to drive innovation in rubbery polymer membranes for CO₂ capture.