THE SURFACE RELAXATION OF GLOW DISCHARGE-TREATED SILICONE POLYMER

The samples of radiationally linked vinyl (1%) methylsilicone elastome r (silicone) were modified in glow-discharge air plasma. Surface relax ation was studied by the data on equilibrium contact angles. The degre e of relaxation is shown to increase with increasing plasma treatment duration, probably due to the increase in the destruction degree of th e spatial network of chemical bonds in the silicone surface layer. The changes in the chemical com position of the surface were controlled u sing attenuated total reflectance-infrared spectroscopy. Plasma treatm ent leads to increase of the polar component of the polymer surface en ergy and increase of the absorption bands of carboxyl and hydroxyl gro ups in its spectra. These characteristics disappear when the samples a re kept in the open air and can be recovered by putting them into wate r. Such behavior can be explained by the fact that the polar oxygen-co ntaining groups, forming on the surface due to plasma treatment, pass inside the polymer. Considering the adhesion properties of modified si licone, its biocompatibility was predicted. (C) 1995 John Wiley and So ns, Inc.