Environmental QCM sensors coated with polypyrrole

Abstract Polypyrrole (PPy) was investigated as an active material for relative humidity and SO 2 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 SO 2 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 SO 2 gives a possibility for the preparation of highly effective environmental and chemical gas sensors.