Chemical sensor based on a novel capacitive microwave flexible transducer with polymer nanocomposite-carbon nanotube sensitive film
Résumé
This study presents the results on the feasibility of a resonant planar chemical capacitive sensor in the microwave frequency range suitable for gas detection and wireless communication applications. The final aim is to develop a low cost ultra-sensitive sensor that can be integrated into a real time multi-sensing platform. The sensors presented in this article are dedicated to the detection of gases such as volatile organic compounds (VOCs) in order to monitor environmental pollution. Experiments were conducted on two devices D1 and D2 which have different geometries notably on the coupling part between electrodes and the position of the sensitive layer based on nanocomposite material PEDOT: PSS-MWCNTs. The preliminary results have shown a large influence of ethanol vapor concentrations on the electrical properties of the passive resonators that constitute each device in the frequency range from 2 to 4 GHz. The sensors sensitivity to ethanol vapor exposition has been estimated to - 0.2 and - 2.2 kHz/ppm for D1 and D2, respectively, according to the resonant frequency shifts for 500–2000 ppm concentrations. The high sensitive surface of the sensor (D2), with possible further functionalization based on various sensitive materials in a large range of electrical conductivity, make it especially interesting for the development of chemical gas sensors for different applications requiring passive and autonomous components at low cost.