Rational design of poly(ethylene oxide) based membranes for sustainable CO2 capture

Abstract

Membrane processes have been becoming a promising approach for effective CO₂ separation due to their inherent merits such as a small footprint, modifiable separation process, and energy efficiency, while a highly permeable/selective membrane material is the key to achieving excellent CO₂ capture performance of membrane processes. Among current membrane materials for CO₂ capture, poly(ethylene oxide) (PEO) as a CO₂-philic polymer shows great potential because of its inherent dipolar–quadrupolar interaction between ethylene oxide (EO) units and CO₂ molecules, whereas pristine PEO membranes typically exhibit low CO₂ permeability due to the crystallinity of PEO chains which limit gas transportation. Therefore, this critical review provides a systematic and in-depth understanding of solution–diffusion theory to help design highly efficient PEO membranes for CO₂ capture. We have classified various strategies to improve PEO based membrane performance into the following three categories: copolymer membrane, cross-linked membrane, and mixed matrix membrane. Furthermore, a brief perspective on the cruxes of future development and promising directions is presented.