Influence of low-temperature plasma and γ radiation on the surface properties of PET track membranes

Resumo

Physical and chemical properties of the surfaces of polyethylene-terephthalate (PET) track membranes (TMs) exposed to low-temperature atmospheric plasma and to γ radiation produced by ⁶⁰Co isotopes are studied. It is established that the exposure to plasma leads to changes in the chemical composition of the surface and increases the number of polar (carbonyl and carboxyl) functional groups in a thin near-surface layer of a TM. The surface energy is also shown to grow owing to its polar component and surface reconstruction. The reconstruction consists in the growth of surface roughness owing to oxidation-reduction reactions, followed by the appearance of destructive areas. These changes promote a lyophilic behavior of the track-membrane surface. Subsequent γ irradiation of the surface is shown to reduce the plasma-modified TM undulation, while decreasing the number of destructive areas and bringing the material into a more equilibrium state.