A quartz crystal microbalance-based sensor system coated with functional polymers for SO2 and NO2 detection.

Area of Science:

• Materials Science
• Chemical Sensing
• Analytical Chemistry

Background:

• Gas sensing technologies are crucial for environmental monitoring and industrial safety.
• Quartz Crystal Microbalance (QCM) sensors offer high sensitivity and real-time detection capabilities.
• Developing selective and reproducible sensing materials remains a key challenge.

Purpose of the Study:

• To design and fabricate a QCM-based adsorption sensor system for selective detection of SO2 and NO2.
• To evaluate the performance of functional polymers (polypyrrole, PEDOT, polystyrene) as sensing materials.
• To assess the practical applicability of the developed sensor system for gas monitoring.

Main Methods:

• Fabrication of a QCM sensor system using 8 MHz AT-cut quartz crystals.
• Coating quartz crystal surfaces with functional polymers: polypyrrole, poly(3,4-ethylenedioxythiophene) (PEDOT), and polystyrene.
• Characterization of sensing materials using Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM).
• Measurement and analysis of QCM frequency shifts upon gas adsorption and desorption.

Main Results:

• Polypyrrole-coated QCM exhibited high selectivity for SO2 gas.
• PEDOT-coated QCM demonstrated high selectivity for NO2 gas.
• The sensor system showed high sensitivity, selectivity, and reproducibility for both gases.
• Successful monitoring of SO2 and NO2 gases at ppm levels in mixtures was achieved.

Conclusions:

• QCM-based adsorption sensors functionalized with specific polymers can achieve selective gas detection.
• Polypyrrole and PEDOT are promising materials for developing dedicated SO2 and NO2 sensors, respectively.
• The developed sensor system is viable for practical monitoring of SO2 and NO2 in mixed gas environments.