Cristian Viespe and Dana Miu
Sensors 2018, 18(7), 2401; https://doi.org/10.3390/s18072401
Abstract
Surface Acoustic Wave (SAW) sensors with several types of polymer sensing films, containing embedded Fe3O4 nanoparticles (NPs) with various dimensions and concentrations, were studied. A sensor with a sensing film consisting of the polymer alone was used for comparison. NPs with a mean diameter of 7nm were produced by laser ablation with 5ns pulse durations, and NPs with 13 nm diameters were obtained with a laser having 10 ps pulse durations. The properties of the Surface Acoustic Wave sensors with such sensing films were analyzed. Their response (frequency shift, sensitivity, noise and response time) to three different volatile organic components at various concentrations were compared with one another. The frequency shift and sensitivity increased with increasing NP concentration in the polymer for a given NP dimension and with decreasing NP diameter for a given concentration. The best results were obtained for the smallest NPs used. The SAW sensor containing 7 nm NPs had a limit of detection of 65 ppm (almost five times better than the sensor with polymer alone), and a response time of about 9 s for ethanol.
SAW sensor; polymer nanocomposite; nanoparticle; VOC detection; pulsed laser ablation
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