B. D. Silverman

Chemical bonding and reaction at metal/polymer interfaces

A combination of surface spectroscopy and microanalytical techniques have been used to investigate the chemical and material characteristics of interfaces formed between metal and a high temperature polymer, polyimide. Results reveal significant chemical reactivity at the interface, as manifested by intermixing and cluster formation. The extent of the material reaction is strongly influenced by the bonding characteristics between metal and the polyimide. Results on Cu and Al are reviewed to illustrate the chemical trend due to increasing reactivity.

The microstructure of metal–polyimide interfaces

We used cross‐sectional transmission electron microscopy techniques to investigate the microstructure of metal/polyimide interfaces. By comparing our results with previously obtained spectroscopy data, we show that the microstructure of these interfaces is strongly related to the tendency of the metal to chemically react with the polyimide at the interface. Cu and Ni do not react with the polyimide and are seen to diffuse inside of the films and form metallic precipitates in the films. Cr reacts with the polyimide at the interface and is thus bounded at the surface, forming a continuous layer on top of the polyimide. Computer simulations are presented that explain the experiment in terms of the different metal–metal and metal–polymer interactions.

Interaction of metals with model polymer surfaces: Core level photoemission studies

Core level photoemission studies have been performed on the in situ interactions of Cr and Cu on two model systems which are related to the pyromellitic dianhydride (PMDA) and oxydianiline (ODA) parts of PMDA–ODA polymide. The model compound which is related to the PMDA constituent is N,N’‐diphenylpyromellitimide and the model polymer which is related to the ODA constituent is poly(2,6‐dimethylphenylene oxide) (PMPO). Cr evaporation on the PMDA model compound changes the PMDA‐related features of the C 1s spectrum, whereas Cu evaporation has comparatively little effect on the PMDA‐related features. The results are consistent with Cr bonding with the PMDA part of the related model compound, or fracturing of the carbonyl bonds and/or other bonds contained in the PMDA structure. Cr evaporation on PMPO results in a new peak at lower binding energy without appreciable changes in the shape of the original bands. Cu predominantly affects the peak in the C 1s spectrum of PMPO which originates from carbons in ether...