Evaluation of poly(2-hydroxyethyl methacrylate) and poly(methyl methacrylate)-grafted poly(vinylidene fluoride)-poly(dimethylsiloxane) bilayers for gas separation

Thin film composites (TFCs) of poly(2-hydroxyethyl methacrylate) (PHEMA) and poly(methyl methacrylate) (PMMA) chain-tethered poly(vinylidene fluoride)-poly(dimethylsiloxane) (PVDF-PDMS) were prepared as a gas separation membrane. PDMS was coated on the PVDF support using a dip coating method. PHEMA and PMMA were then grafted on PVDF-PDMS substrate by atom transfer radical polymerization. The PVDF-PDMS-PHEMA and PVDF-PDMS-PMMA trilayer membranes were studied by attenuated total reflection Fourier transform infrared spectroscopy, scanning electron microscopy, atomic force microscopy, water contact angle measurement, and X-ray photoelectron spectroscopy. The results of separation tests indicated that the CO 2 /N 2 selectivity of PVDF-PDMS-PHEMA and PVDF-PDMS-PMMA TFCs increased by ∼2 and ∼3 times, respectively, compared to the solvent-extracted PVDF-PDMS support.