Plasma induced graft polymerization of hydrophilic monomers on polysulfone gas separation membrane surfaces

•AA and PEG were completely grafted on the surface of PSF membranes.•Hydrophilicity of PSF membranes was permanently improved over 120 days by the Ar/O2 plasma induced graft polymerization of AA and PEG.•Grafting yield increased with increasing of plasma treatment and grafting times.•Ideal CO2/CH4 separation performance was slightly enhanced.

Active groups were induced on the surface of polysulfone (PSF) membranes by DC Ar/O2-plasma and hydrophilic monomers, acrylic acid (AA) and polyethylene glycol (PEG), were post-grafted. Membrane samples were characterized by several techniques to confirm the tailoring of membrane surfaces. Hydrophilic properties were evaluated in terms of water contact angle in sessile drop mode measurement. Morphological structures were analyzed through SEM and AFM images. Creation of functional groups was determined by ATR-FTIR while grafting yield was estimated by weighing of membrane both before and after grafting. Permeation of CO2 and CH4 gases through membrane was also measured. Results showed that the hydrophilic property of PSF membrane surface grafted by PEG was permanently improved over 120 days. The CO2/CH4 separation performance was slightly enhanced from 54.06 to 60.05.

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