Robert G. Spahn

Salt bath test for assessing the adhesion of silver to poly(ethylene terephthalate) web

A time-resolved salt bath technique was employed for assessing the adhesion of silver coatings on poly(ethylene terephthalate) (PET) web. Furthermore, a basis for quantitative comparisons of adhesion was developed. The salt bath test was applied to samples of silver on PET web, made with a variety of web surface treatments. The results of the salt bath test demonstrate that the technique is capable of distinguishing levels of adhesion and, therefore, levels of treatment. It is thus shown that the salt bath test can be used to study the effects of treatment and coating process parameters on the adhesion of silver coatings to PET substrates. Although the test is specifically applied to the case of silver on PET, the concepts of a time-resolved soak test are generally applicable to systems that are known to exhibit delamination when exposed to certian chemical agents or harsh environments.

Investigation of the locus and mechanism of adhesion failure during peel tests on copper-chromium coated polyimide systems

Auger depth profiling and X-ray photoelectron spectroscopy (XPS) techniques were used to elucidate the adhesion process in copper-chromium coated polyimide. Metal layers were sputter-deposited on polyimide, which was modified by glow discharge under various conditions. The results showed that glow discharge could increase the chromium coverage on polyimide, improve or deteriorate adhesion at various interfaces, and change the locus of adhesion failure. Auger depth profiles could explain the various failure modes by revealing the chemistry at each interface. Additional information was provided by XPS results obtained from surfaces generated by failure. The effects of accelerated aging on this metal-polymer system were also studied.