Modification of polysulfone membranes. 2. Plasma grafting and plasma polymerization of acrylic acid

Polysulfone membranes were modified with acrylic acid using plasma initiate d graft polymerization (both in solution and vapor phase) and plasma polyme rization. Changes on the surface were monitored by contact angle measuremen ts and FTIR-ATR technique. Pore size and ultrafiltration properties were al so evaluated. Grafting in solution gave as a result hydrophobic membranes w ith pore size diameter significantly reduced. Such membranes lost their ult rafiltration properties. Grafting in vapor phase seems to give brush-like s tructure. Membranes possess hydrophilic surface and unique filtration prope rties in basic environment. Plasma polymerization of acrylic acid on the PS U surface creates a layer of material highly reminding pure poly(acrylic ac id). Performance of such membranes was also pH-dependent showing better pro perties in basic solution.