Effect of the metal on metal/polymer contacts.

Thermally stimulated currents (TSC) of ionomer/polyethylene blends were investigated. Experimental results obtained for aluminum, indium, lead, pressed gold, and evaporated gold electrodes are reported. The peak temperature and peak current observed for the high-temperature α peak was found to vary approximately linearly with the literature value of the work function of the metal. This is ascribed to differences in the ease of electron injection and its microscopic reverse. The lower temperature beta peaks showed differences with different electrode metals. Positive beta peaks were observed using lead electrodes whereas the gold electrodes always produced negative beta peaks. With aluminum electrodes, homopolymers showed negative beta peaks. Variables such as the partial oxidation of the metal and possible morphologic changes of the polymeric sample during the electrode evaporation were considered. After examining the effect on TSC of the various metal electrodes, evaporated gold was chosen as the best electrode material TSC studies.