STUDY OF s-CNTs AND PANI/CNTs NANOCOMPOSITES FOR GAS SENSORS DEVELOPMENT

Implementation of feasible technical solutions to be applied in manufacturing of sensible, selective and stable sensing devices, used for the detection/measurement of different gases and chemical compounds, its nowadays a technological high demand due to the widespread of application areas and the critical issues that can support. Regardless of the transduction mechanism used by a specific sensor, the parameter that pinpoints the differentiation of chemical compounds or gases, to which the sensors active layers are sensitive, is the modification of electrical conductivity. In this paper, preparation methods and characterization of different active mixture form of sulfonated CNTs (s-CNTs) and also a mixture form of carbon nanotubes (CNTs) with polyaniline (PANI) used as active layer for chemiresistive sensors are reported. Aspects regarding detection mechanisms for both type of active layers and also data analysis were presented in the paper. Considering as a great advantage their unique electronic, chemical, and mechanical properties, carbon nanotubes (CNTs) were chosen to prepare both of the mixture. Polyaniline (PANI) is characterized as a conducting polymer identified as an oxidation state of aniline, also largely used in gas sensing applications due to its ease of synthesis and selectivity capability for various gases. Depending on the doping level of the CNTs, estimated by relative carbon content, for both mixture of sulfonated CNT (s-CNTs) and also mixture of CNTs/PANI an analogy based on the obtain results was also presented in this work. As a main conclusion, the obtained microsensors structures, for both s-CNTs and CNTs/PANI active mixture, act like resistive sensors and are viable solutions for different gases (CO, CO2 and NH3) detection. The results exposed in this paper concluded that the active mixtures are characterized by high electrochemical activity and improved stability regardless of their different equimolar proportions synthetization by chemical polymerization or oxidative doping.