Activation of polyimide by oxygen plasma for atomic layer deposition of highly compact titanium oxide coating.

Titanium oxide (TiO) coated polyimide has broad application prospects under extreme conditions. In order to obtain a high-quality ultra-thin TiOcoating on polyimide by atomic layer deposition (ALD), the polyimide was activated byoxygen plasma. It was found that a large number of polar oxygen functional groups, such as carboxyl, were generated on the surface of the activated polyimide, which can significantly promote the preparation of TiOcoating by ALD. The nucleation and growth of TiOwere studied by x-ray photoelectron spectroscopy monitoring and scanning electron microscopy observation. On the polyimide activated by oxygen plasma, the size of TiOnuclei decreased and the quantity of TiOnuclei increased, resulting in the growth of a highly uniform and dense TiOcoating. This coating exhibited excellent resistance to atomic oxygen. When exposed to 3.5 × 10atom cmatomic oxygen flux, the erosion yield of the polyimide coated with 100 ALD cycles of TiOwas as low as 3.0 × 10cm/atom, which is one order less than that of the standard POLYIMIDE-ref Kaptonfilm.