Surface-attached brush-type CO2-philic poly(PEGMA)/PSf composite membranes by UV/ozone-induced graft polymerization: Fabrication, characterization, and gas separation properties

Abstract

CO2-philic brush-type poly(poly(ethylene glycol) methyl ether methacrylate)(poly(PEGMA)) was fabricated onto microporous polysulfone (PSf) substrates by ultraviolet (UV)/ozone induced graft polymerization. The PSf substrates were first exposed under UV/ozone to form peroxide groups, which were thermally decomposed to form peroxide radical groups. The substrates were then soaked in aqueous PEGMA solutions to form thin brush-type poly(PEGMA)/PSf composite membranes. The concentration of peroxide was measured by ATR-FTIR and 1,1-diphenyl-2-picrylhydrazyl (DPPH) methods and increased up to 113.75 nM/cm2 at 6min. ATR-FTIR, XPS, and FE-SEM confirmed poly(PEGMA) selective layers without defects were attached well onto the substrate surface and had a thickness of about 750 nm. The optimized composite membranes exhibited noteworthy separation performance; high selectivities of αCO2/H2=13.36, αCO2/CO=43.4, and αCO2/N2=59.41, respectively, and CO2 permeance of 85.47 GPU at 35 oC. This study suggests a facile and effective way to develop composite membranes suitable for CO2 separation and has remarkable potential for other membrane applications.