An ESCA study of the surface ozonation of polystyrene film

Polystyrene film was treated with 0.27 mol % ozone in oxygen at room temperature. Changes in the surface were monitored by ESCA. Reaction occurred uniformly in at least the outermost 60 Å of the film. Reaction was rapid, giving a surface composition that corresponded to C1.8O after about 8 h, with no apparent yellowing or embrittlement of the polymer. Ether, ketone, and carboxyl groups were formed at uniform, but not equal, rates in the outer 60 Å of the polymer. With short reaction times the less highly oxidized groups were the main oxidation product, but after about 4 h the highly oxidized groups predominated. The aromatic rings underwent reaction as indicated by the rapid disappearance of the C1s shake‐up satellites on ozonation.