Adsorption-induced unusual changes in the electrical conductivity of 1,1 '-diacetylferrocene and 1,1 '-ferrocenedicarboxylic acid

The effects of adsorption (at 268 K) of ethanol vapor on the electrical con ductivity of 1,1'-diacetylferrocene and 1,1'-ferrocenedicarboxylic acid in powder form have been studied by sandwich-type cell technique. A peak has b een observed in the current vs. temperature plots in a specific temperature region. The effects of vapor pressure and heating rate on the temperature (T-max) at which the peak appears as well as the magnitude of the peak have been studied in detail. The experiment has indicated two activation energy values of these materials in the vapor-adsorbed state and these values are higher than the values for pure dry state. The unusual changes in the adso rption-induced electrical conductivity of these materials in a specific tem perature range are possibly related to the adsorption-induced phase transit ion in these materials. (C) 1999 Elsevier Science S.A. All rights reserved.