EVIDENCE AND MECHANISMS OF FILLING POLYMERIZATION BY PLASMA-INDUCED GRAFT-POLYMERIZATION

Using a plasma-induced graft polymerization technique, which is well k nown as a surface modification method, the grafted polymer was formed in pores of the porous material. This study examined the filling mecha nism. Five thin porous films were sandwiched together, and employed as the substrate. The substrate was treated by plasma, and the change in surface tension and radical formation was measured for each sheet aft er the sheet were separated. The only surface on which surface-tension change was detected, was that of the sheet directly exposed to the pl asma. Although plasma treatment made polymer radicals primarily on the outer surface of the sheet, the treatment also formed a few radicals inside the sheets. The radicals inside the sheets reacted with methyla crylate and grafted polymer formed in the pores. The location of graft ed polymer depended on the balance between monomer diffusivity and rea ctivity. The grafting rate depended on which monomer solvent was used for the polymerization. Thus, the grafted membrane morphology could be controlled by varying the grating solvent composition. (C) 1996 John Wiley & Sons, Inc.