NEAR-SURFACE STRUCTURE OF AROMATIC POLYIMIDES - THE EFFECT OF PRECURSOR ISOMERS

The near-surface structure of an aromatic polyimide has been investiga ted as a function of the isomeric form of the precursor alkyl ester. U sing grazing-incidence X-ray scattering, enhanced ordering was observe d within 10 nm of the air surface for films prepared from both the met a- and para-isomers of the precursor. However, the extent of ordering is much less for the polyimide prepared from the meta-alkyl ester. Thi s is consistent with the extent of ordering observed in the bulk mater ial. The results suggest a correlation between the extent of ordering near the surface and the persistence length of the polymer.