Carbon nanotubes-coated multi-transducing sensors for VOCs detection

Langmuir-B lodgett (LB) films consisting of tangled bundles of single-walled carbon nanotubes (SWCNTs) have been used as sensing nanomaterials onto three different types of sensory systems using complementary transducing principles as surface acoustic waves (SAWs), quartz crystal microbalance (QCM) and standard silica optical fiber (SOF) for volatile organic compounds (VOCs) detection, at room temperature. The multi-transducing probes have been configured as 433 MHz SAW oscillator, 10 MHz QCM oscillator, and SOF reflectometry-based system at a wavelength of 1310 nm. A nanocomposite film of SWCNTs embedded in a cadmium arachidate (CdA) matrix was deposited by LB methodics onto SAW sensors. A LB multilayer of SWCNTs-onto-CdA buffer material was deposited onto QCM and SOF sensors. Highly sensitive, repeatable and reversible responses of the SWCNTs sensors indicate feasible VOCs detection in a wide mmHg vapor pressures range. The VOCs sensing performance of the SWCNTs-based multi-transducing sensors will be discussed. (c) 2005 Elsevier B.V. All rights reserved.