Soft polymeric nanoparticle additives for next generation gas separation membranes†
Abstract
This article highlights a new approach of fabricating a gas separation membrane through the addition of well-defined soft polymeric nanoparticles into the existing polymeric structure. Well-defined soft polymeric nanoparticles based on novel poly(ethylene glycol) (PEG) and poly(ethylene glycol)-b-poly(dimethylsiloxane) (PEG-b-PDMS) grafted star polymers were synthesized via atom transfer radical polymerization (ATRP) and the ‘core-first’ approach in high conversions and high yields. Thin film composite (TFC) membranes with selective layers prepared from commercially available poly(amide-b-ether) (Pebax® 2533) blended with a series of these PEG and PEG-b-PDMS nanoparticles are prepared. Their ability to selectively separate carbon dioxide (CO2) from nitrogen (N2) was studied at 35 °C and an upstream pressure of 3.4 bar. The fabricated TFC membranes exhibited greatly improved flux. These results demonstrate the ability of soft polymeric nanoparticles to form localized, high flux, CO2 permeable domains within a selective matrix, which in turn leads to an increase in the gas separation performance.