Multinanosensors based on MWCNTs and biopolymer matrix-production and characterization

This study presents the results of the design and characterization of a gas sensor with PMMA/CNTs chemiresistor as sensing element for detection of organic vapors. Multi wall carbon nanotubes (MWCNTs) produced at our lab (by method of pyrolysis, outer diameter d = 10 ÷ 40 nm, purity ? 94%) were incorporated into biocompatible polymer matrix. Poly(methyl methacrylate) - PMMA - and nanocomposite films were obtained using casting solution technique. Produced nanocomposite films were investigated with thermogravimetric analysis, differential scanning calorimetry, X-ray analysis, scanning electron microscopy, and Fourier transform infrared, while the sensors activity was determined by the changes in electrical resistance of the nanocomposite films due to acetone and chloroform exposure. The response to these vapors was evaluated and it was shown that PMMA/MWCNTs composites exhibit changes in electroresistivity. Sensitivity was calculated to be in 0.58-54.6 range (30 min exposed to acetone) and 0.53-10.35 (30 min exposed to chloroform). The results presented in this paper show that CNTs are able to improve the overall performances of polymer based sensors.