Highly selective filler–polymer gaps in situ fabricated in mixed matrix membranes for gas separation

Abstract

We proposed an interface self-assembly strategy to build high speed gas transport channels throughout mixed matrix membranes (MMMs) in situ using the gaps between hydrophilic polymers and hydrophobic fillers that are normally considered as defects that reduce the gas separation performance of MMMs. Herein, a series of hydrophobic halogen-induced metal polymer (HMP) fillers were synthesized in situ on a hydrophilic organic interface layer, and hydrophilic polymer PVAm was further coated on the filler particles to form regular gaps between the PAVm matrix and the HMP particles. The gap sizes were tuned from 0.76 nm to 1.20 nm by regulating the electronegativity differences between the fillers and PVAm. The designed gaps with a thickness of ∼270–300 nm can act as high speed gas transport channels, showing excellent CO₂/N₂ separation performance. This work provides a promising strategy to utilize the defects in MMMs to fabricate high performance MMMs.