A Model for Solventless PMDA/ODA Polyamic Acid: Consequences for the Reactivity of Polyamic Acid with Metals

In this article we discuss the core level spectra of solventless prepared polyN,N-p,p-oxydiphenylene pyromellitamic acid or PMDAODA polyamic acid PAA films with particular emphasis on the chemical composition and on the 01s and c1s shake up transitions. Both vapor deposited polyamic acid and the resulting polyimide films show an excess of oxydianiline ODA and a deficiency of carbonyl groups. A qualitative analysis of the shake up transitions on the 01s and C1s core holes indicate that polyamic acid is in a non-planar conformation. A shoulder in the N1s band at higher binding energy was assigned to positively charged nitrogen and we concluded that a proton is transferred from the amic acid group onto the nitrogen and we concluded that a proton is transferred from the amic acid group onto the nitrogen atom of unreacted oxydianiline. The amic group of the molecule is the primary site of interaction with evaporated gold atoms and with bulk silver surfaces. In the case of polyamic acid and polyimide films on polycrystalline silver the interfacial bonding is achieved via silver carboxylate linkages. JS