Chemical sensor based on percolation principle -humidity sensor behavior of carbon-montmorillonite composite

Abstract

In the percolation process, the resistivity changes abruptly at a certain mixing ratio of conductor to insulator. In this study, we first applied this percolation principle to chemical sensor. By using montmorillonite as insulator and carbon as conductor, we successfully fabricated a humidity sensor whose resistivity increases in a humid atmosphere and decreases in a dry atmosphere. The resistivity change is due to the volume change of montmorillonite by water adsorption and desorption. A new type of chemical sensor based on the percolation principle is proposed.