This work is focused on the room temperature sensitivities and response times analysis against aromatic volatile organic compounds of both silica optical fiber and quartz crystal microbalance sensors, coated by Single-walled Carbon Nanotubes Langmuir-Blodgett multilayers as highly sensitive nanomaterials. The fabricated samples have been characterized by means of X-ray diffraction, high-resolution transmission electron microscopy and scanning electron microscopy, SOF and QCM transducers have been simultaneously exposed at room temperature to toluene and xylene individual vapors in the ppm range. For each transducer type, a time division multiplexing approach has been carried out, enabling the simultaneous interrogation of up to 8 optical and 6 acoustic probes, respectively. The results obtained indicate that both optical and acoustic sensors provide very high reproducibility and sensitivity either towards toluene or xylene, with a resolution of few hundreds of ppb. Furthermore, sensitivities and response times have been found to be dependent on the particular analytes used for the vapors testing. Both transducer types demonstrate a similar response time, while with regard the recovery time, the optical detection seems to be significantly faster than the electrical counterpart. The effect of the SWCNTs monolayers number on sensors sensitivity and response time has been also investigated, demonstrating the possibility to enhance the performances of the proposed transducers by tailoring the geometric properties of the sensitive nanomaterial.

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