Plasma polymerization of TEOS for QCM-based VOC vapor sensing

¹ Université Mentouri de Constantine, Laboratoire des Études de Matériaux Électroniques pour Applications Médicales (LEMEAMED), Faculté des Sciences de l’Ingénieur, Constantine 25000, Algeria
² Université Mentouri de Constantine, Laboratoire de Microsystèmes et Instrumentation (LMI), Faculté des Science de l’Ingénieur, Constantine 25000, Algeria
³ Universités de Toulouse, Laboratoire Plasma et Conversion de l’Énergie (LAPLACE), CNRS, INPT, Université Paul Sabatier, 118 Route de Narbonne, 31062 Toulouse Cedex, France

^a e-mail: azzedine.bellel@gmail.com

Received: 11 April 2011
Revised: 16 July 2011
Accepted: 13 September 2011
Published online: 28 October 2011

Abstract

Plasma polymerized tetraethoxysilane (ppTEOS) thin films deposited on quartz crystal microbalance (QCM) electrode were used as sensitive layer for the detection of a number of volatile organic compounds (VOCs) such as methanol, ethanol, acetone and chloroform molecules. Their sensing properties were examined by measuring the resonance frequency shifts (∆f) of QCM which are due to additional mass loading. The results showed that ∆f of QCM were found to be linearly correlated with different vapor pressure of analyte. The sensor showed good reproducibility and reversibility. The ppTEOS film is found to be highly sensitive to methanol vapor than other vapors. Fourier transform infrared spectroscopy (FTIR) analysis showed the presence of CH_x peaks around 2962 cm⁻¹ making the elaborated layer more porous and low dense, resulting in the promotion of VOC vapor diffusion into the film.