Change of electrical resistance of carbon films during the adsorption of acetone and other molecules

Carbon films were prepared from polyimide films (Kapton and Upilex-s with thickness of 50 μm) by heat treatment at 750 °C under Ar atmosphere. The electrical resistance of the carbon films was remarkably increased with the adsorption of acetone and decreased with its desorption. The magnitude of the resistance change increased with increasing vapor pressure of acetone and with decreasing temperature. The weight and resistance changes during the adsorption of acetone were simultaneously determined. A linear relationship was confirmed between them. It was also found that similar resistance changes were observed for adsorption of aqueous ammonia and nitric acid.