This work is focused on the performances anal. of silica optical fiber (SOF) and quartz crystal microbalance (QCM) volatile org. compds. (VOCs) sensors, coated by single-walled carbon nanotubes (SWCNTs) multilayers, towards toluene and xylene vapors, at room temp. The Langmuir-Blodgett (LB) technique was used for the deposition of carbon nanotubes directly onto the optical and acoustic sensors substrates. A time division multiplexing approach was used to simultaneously test up to eight SOF and six QCM chem. sensors in the same test chamber. The results obtained demonstrate good sensitivity, fast response and high repeatability provided by the proposed sensors even at very low concns. Resolns. in the ppm and sub-ppm range were found towards the tested VOCs, for both optical and acoustic transducers. The effects of the SWCNTs film thickness and even of a cadmium arachidate (CdA) buffer multilayer, exploited in the past to improve the adhesion of nanotubes onto the sensors substrates, on the performances of SOF and QCM transducers were studied. To the aim, several optical and acoustic sensors with a different no. of SWCNTs LB layers, directly deposited onto optical fibers and quartz surfaces and buffered by a CdA linker material, were fabricated and simultaneously exposed, at room temp., to different concn. pulses of toluene and xylene. The results obtained demonstrate the possibility to use the data coming from carbon nanotubes SOF and QCM sensors to improve the VOC discrimination by the hybrid system based on these two complementary transducers by pattern recognition methods.
Carbon nanotubes thin films fiber optic and acoustic VOCs sensors: Performances analysis.
Giordano Michele;
2006
Abstract
This work is focused on the performances anal. of silica optical fiber (SOF) and quartz crystal microbalance (QCM) volatile org. compds. (VOCs) sensors, coated by single-walled carbon nanotubes (SWCNTs) multilayers, towards toluene and xylene vapors, at room temp. The Langmuir-Blodgett (LB) technique was used for the deposition of carbon nanotubes directly onto the optical and acoustic sensors substrates. A time division multiplexing approach was used to simultaneously test up to eight SOF and six QCM chem. sensors in the same test chamber. The results obtained demonstrate good sensitivity, fast response and high repeatability provided by the proposed sensors even at very low concns. Resolns. in the ppm and sub-ppm range were found towards the tested VOCs, for both optical and acoustic transducers. The effects of the SWCNTs film thickness and even of a cadmium arachidate (CdA) buffer multilayer, exploited in the past to improve the adhesion of nanotubes onto the sensors substrates, on the performances of SOF and QCM transducers were studied. To the aim, several optical and acoustic sensors with a different no. of SWCNTs LB layers, directly deposited onto optical fibers and quartz surfaces and buffered by a CdA linker material, were fabricated and simultaneously exposed, at room temp., to different concn. pulses of toluene and xylene. The results obtained demonstrate the possibility to use the data coming from carbon nanotubes SOF and QCM sensors to improve the VOC discrimination by the hybrid system based on these two complementary transducers by pattern recognition methods.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.