Surface modification of polystyrene by photoinitiated introduction of cyano groups

Abstract

The surface of polystyrene was modified by the introduction of CN groups. This was achieved by irradiating the polymer with UV light (254 nm) in the presence of gaseous cyanogen bromide (BrCN). X-ray photoelectron spectroscopy (XPS) and FTIR analysis showed that after irradiation both Br and CN groups were covalently bound to the polymer surface. Quantitative XPS analysis revealed that upon prolonged irradiation every second monomer unit at the surface was modified with a CN group. It was demonstrated that photochemical techniques can be employed to attach specific functional groups onto polymer surfaces.