Poly(poly(ethylene glycol) methyl ether acrylate) micelles for highly CO2 permeable membranes

Abstract

Herein, we report highly CO2-permeable membranes obtained by blending in situ self-assembled micellar-structured poly(poly(ethylene glycol) methyl ether acrylate) (PPEGMEA) with poly(ether-block-amide) (Pebax). PPEGMEA with different molecular weights were prepared by varying the concentration of benzoyl peroxide (BPO) in a Pebax/PEGMEA/BPO mixture during radical polymerization. Significantly, the Pebax/PPEGMEA (30/70 w/w) blend membrane comprised highly CO2-philic PPEGMEA micelles, which appreciably increased the d-spacing of the Pebax matrix. Consequently, the blend membrane containing a high molecular weight of PPEGMEA exhibited an unprecedented CO2 permeability enhancement of 1054% compared to the pristine Pebax membrane while maintaining good CO2 selectivity relative to H2, O2, N2, CO, and CH4 because of the enriched polyethylene glycol moieties. This excellent separation performance was maintained for 100 h, validating the good long-term separation performance of the membrane. Furthermore, the membrane exhibited good mechanical strength and plasticization tolerance, resulting in excellent CO2 separation performance under equimolar CO2/N2 or CO2/CH4 mixed gas conditions (CO2 permeability of 1250 Barrer and CO2/N2 and CO2/CH4 selectivity of 31.5 and 12.7, respectively), up to a CO2 partial pressure of 10 atm. Our simple but effective in situ micelle-induced blending approach is a significant step toward realizing high-performance CO2 separation membranes.