High‐performance thin film composite membranes with well‐defined poly(dimethylsiloxane)‐<i>b</i>‐poly(ethylene glycol) copolymer additives for CO₂ separation

Abstract

ABSTRACT A series of well‐defined diblock copolymers (BCPs) consisting of poly(ethylene glycol) (PEG) and poly(dimethylsiloxane) (PDMS) were synthesized and blended with commercially available PEBAX® 2533 to form the active layer of thin‐film composite (TFC) membranes, via spin‐coating. BCPs with a PEG component ranging from 1 to 10 kDa and a PDMS component ranging from 1 to 10 kDa were synthesized by a facile condensation reaction of hydroxyl terminated PEG and carboxylic acid functionalized PDMS. The BCP/PEBAX® 2533 blends up to 50 wt % on cross‐linked PDMS gutter layers were tested at 35 °C and 350 kPa. TFC membranes containing BCPs of 1 kDa PEG and 1–5 kDa PDMS produced optimal results with CO 2 permeances of approximately 1000 GPU which is an increase up to 250% of the permeance of pure PEBAX® 2533 composite membranes, while maintaining a CO 2 /N 2 selectivity of 21. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53 , 1500–1511