Environmental QCM sensors coated with polypyrrole

Polypyrrole (PPy) was investigated as an active material for relative humidity and SO2 gas sensors. PPy films of different thickness were deposited on the both sides of quartz crystal microbalance (QCM) disks. The dependence of resonant frequency of those QCM-based sensors on relative humidity was investigated. Also, the dependence on SO2 was measured in the atmosphere of nitrogen at room temperature in the concentration range from 0 to 100%. Very good sensitivity of PPy coated QCM disks to atmospheric humidity and concentration of SO2 gives a possibility for the preparation of highly effective environmental and chemical gas sensors.