ADSORPTION-INDUCED ELECTRICAL-CONDUCTIVITY OF FERROCENE - RATES OF ADSORPTION AND DESORPTION OF VAPORS

This paper deals with the change in the dark conductivity (proportional to the current) of ferrocene in a sandwich-type of cell configuration upon adsorption of some organic vapors at different cell temperatures. Rates of the adsorption and desorption processes were studied by the measurement of the adsorption/desorption-induced electrical current in ferrocene cells. On adsorption of vapors an appreciable enhancement in the current is observed. Enhancement depends on the vapor pressure of the adsorbed vapor, sample cell temperature and also on the chemical nature of the solvent. Enhancements are smaller for lower cell temperatures, which is unusual. The adsorption process is physical and the observed desorption in general is slower than that of the adsorption. Both the adsorption and desorption rates follow the modified Roginsky-Zeldovich equation. The temperature-dependence and the nature of the interaction of the vapor molecules with the solid material were deduced by rate data analysis. Some interesting results were obtained.