Aging Process in Plasma-Polymerized Organosilicon Thin Films

Abstract

The atmospheric aging process in plasma-polymerized organosilicon thin films was studied. The investigations were carried out for plasma polymers produced from methylsilane, methylsilazane, and methylsiloxane, structurally different monomers. ATR-IR spectroscopic examinations revealed the strong effect of aging on the films structure. The formation of [sbnd]OH, >C[dbnd]0, Si[sbnd]O[sbnd]Si, and Si[sbnd]O[sbnd]C groups and the decay of SiH groups were found to be general trends in the structural changes of the plasma polymers investigated that resulted from aging. Mechanisms of the reactions contributing to the aging process were discussed. Kinetic studies indicated that the aging process is controlled by the diffusion of atmospheric oxygen and water into the film. Wettability data showed that aging produces distinct changes in the surface energy components of the films, increasing the dispersion component and decreasing the polar component. This trend was consistent with the structural changes observed for aged films.