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

Polysulfone membranes were modified with acrylic acid using plasma initiated graft polymerization (both in solution and vapor phase) and plasma polymerization. Changes on the surface were monitored by contact angle measurements and FTIR-ATR technique. Pore size and ultrafiltration properties were also evaluated. Grafting in solution gave as a result hydrophobic membranes with pore size diameter signficantly reduced. Such membranes lost their ultrafiltration properties. Grafting in vapor phase seems to give brush-like structure. Membranes possess hydrophilic surface and unique filtration properties in basic environment. Plasma polymerization of acrylic acid on the PSU surface creates a layer of material highly reminding pure poly(acrylic acid). Performance of such membranes was also pH-dependent showing better properties in basic solution.