Enhancement of Poly(vinyl chloride) Electrolyte Membrane by Its Exposure to an Atmospheric Dielectric Barrier Discharge Followed by Grafting with Polyacrylic Acid

A poly(vinyl chloride) (PVC) membrane was exposed to atmospheric-pressure dielectric barrier discharge and subsequently wet-chemically grafted with poly(acrylic acid) (PAA) and then consumed with poly(ethyleneimine) (PEI). The thus modified membrane was characterized by measurement of the static water contact angle, by scanning electron microscopy, infrared spectroscopy (ATR-FTIR), thermogravimetry (TGA) and electrolytic responses. The TGA favors a thermally stable grafted PVC membrane. The ATR-FTIR revealed the existence of an ultra-thin PAA layer grafted onto the surface of the plasma-modified PVC membrane. The ion exchange capacity measurement of the grafted poly(vinyl chloride) (PVC–PAA) sample was close to that of additionally wet-chemically aminated with PEI for 12 h or more (PVC–PAA–PEI). It means that PVC–PAA membranes do not need necessarily further modifications. As concomitant helpful effect, it was observed that the swelling degree of the PVC membrane was reduced after plasma exposure due to plasma-induced crosslinking.