Grazing incidence x-ray scattering studies of thin films of an aromatic polyimide

Abstract

Grazing incidence X-ray scattering measurement of the near surface structure of poly(pyromellitic dianhydride-oxydianiline) (PMDA-ODA) are reported. The structure parallel to the film surface was investigated as a function of thermal treatment and film thickness. The PMDA-ODA structure was studied as a function of the X-ray penetration depth. For thick films (≃2500 A), it was found that near the air surface the PMDA-ODA was more ordered than in the bulk of the specimen, and for thermal treatment above 300°C, a crystalline-like ordering was observed; In the near surface region the PMDA-ODA molecules locally assumed a more planar zigzag conformation. However, the interchain packing, i.e. the coherence of order normal to the chain axis was markedly improved