Abstract
A quartz crystal microbalance (QCM) sensor coated with a thin film of polyaniline was used as a sensitive
method for the determination of a number of following vapours: Ether, Chloroform, Carbon tetrachloride and
Ethyl acetate. The detection was based on the absorption of the vapours of these organic compounds into the film
by using gas cell chamber. The detection of these vapours can be obtained in part per million (ppm). The work
includes the use of polyaniline films with different thickness (55, 82, 102 and 153) nm where thickness of the
PANI films was controlled by the spin coating process.
Results show that increasing of sensitivity with increase of the concentration of injected analyte when the PANIfilm-coated QCM was exposed to the vapours of ethanol, propanol hexane and benzene. Best sensitivity to
ethanol and hexane were obtained with film thicknesses 93nm while in the case of propanol best results were
obtained with thickness of 118 and 93 nm. Thickness of 93 and 176 nm gave good sensitivity to benzene.
Keywords: QCM, Polyaniline, Vapors, Sensor, Thickness .
1. Introduction
Since the quartz crystal microbalance (QCM), was first introduced by Sauerbrey in 1959, it has become a largely
used instrument for small mass measurements in vacuum, gas, and liquid phase. On the other hand, the quartz
crystal microbalance (QCM), which became a largely used instrument during the last decades, can detect up to
10-16 kg (Mecea 2005). Many years ago, the chemical sensors have made great advances and have taken root in
human life and industry as a feature of modern technology. In recent years, polymers have found an increasing
role in sensorics due to their unique characteristics, and a number of new sensors have been developed (Hosseini
et al.