Chemical Protection of Polycarbonate Surfaces by Atomic Layer Deposition of Alumina with Oxygen Plasma Pretreatment

This study reports the effect of an O₂ plasma pretreatment of polycarbonate (PC) films for the enhanced integration of Al₂O₃ films prepared by atomic layer deposition (ALD) on the PC substrate. It is revealed that the plasma treatment produces functional groups on the PC surface, which are essential for the ALD of Al₂O₃. Specifically, it is revealed that a significant amount of carbonyl groups, essential for the chemisorption of the precursors and covalent binding with the Al₂O₃ surface protection layer, are present in the plasma‐treated PC surface. To evaluate the chemical resistivity of the PC‐ALD alumina film, an acetone immersion test is conducted. As a result, a severe degradation occurs in the plasma‐untreated PCs, even with a sufficiently thick ALD alumina protection layer. In contrast, the PCs that are plasma‐treated and coated with the ALD alumina exhibit a significantly improved stability against acetone etching. Light transmittance and surface morphology analysis support this improvement.