Atomic oxygen effects on silvered polyimide films and their surface modification by poly(siloxane amic acid) ammonium salts.

The tolerance of silvered polyimide films synthesized by an self-metalization method against atomic oxygen (AO) was evaluated. The results showed that the mass loss of R-Ag/PI was markedly increased as the AO fluence increased; Ag/PI showed an identical trend. SEM data showed that the silver particles on the surfaces of R-Ag/PI and Ag/PI disappeared. The surfaces achieved a "carpet condition" that was more obvious as the AO fluence increased. Poly(siloxane amic acid) ammonium salt was synthesized and made imidization to produce a flexible organic coating that was characterized by ATR-FTIR, HNMR, TGA, and XPS. This could be used to improve the tolerance of silvered polyimide films against AO. The AO resistance and the impacts on mass loss, surface morphology, and surface compositions were also evaluated after surface modification by poly(siloxane amic acid) ammonium salts. 20 wt% Foc/Ag/PI had a lower mass loss and smoother surface than the others due to the formation of a compact surface-SiO-type layer. This flexible organic coating can be produced an environmentally-friendly method, and it maintains the inherent thermal stability of the polyimide which cannot be achieved by other anti-AO coatings.