Polymer coated quartz crystal microbalance sensors for the detection of volatile organic compounds

Abstract

In this work, plasma polymerization of tetraethoxysilane (TEOS) has been used for producing QCM chemical sensors. The sensor was exposed towards the methanol and chloroform molecules. The measured isotherms on modified QCM electrode showed a good reproducibility and reversibility. Generally, the frequency shift (∆f) of QCM increases linearly with the vapor concentration. The evolution of sensor response showed clearly an improvement of the QCM sensibility. However, the film elaborated from 50% of TEOS and 50% of O2 was found to be significantly more sensitive than film deposited from high proportion of oxygen due to dense structure. Concerning the selectivity, the results revealed a good affinity of the layer to methanol molecules. Fourier transform infrared spectroscopy (FTIR) analysis showed that VOCs molecules interact via hydrogen bonding due to the presence of the –OH group in the elaborated layers.