Analysis of Liquid-Phase Chemical Detection Using Guided Shear Horizontal-Surface Acoustic Wave Sensors

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• 作者：Zhonghui Li ; Yolanda Jones ; Jeanne Hossenlopp ; Richard Cernosek ; and Fabien Josse
• 刊名：Analytical Chemistry
• 出版年：2005
• 出版时间：July 15, 2005
• 年：2005
• 卷：77
• 期：14
• 页码：4595 - 4603
• 全文大小：388K
• 年卷期：v.77,no.14(July 15, 2005)
• ISSN：1520-6882

文摘

Direct chemical sensing in liquid environments usingpolymer-guided shear horizontal surface acoustic wavesensor platforms on 36 rotated Y-cut LiTaO₃ is investigated. Design considerations for optimizing these devicesfor liquid-phase detection are systematically explored.Two different sensor geometries are experimentally andtheoretically analyzed. Dual delay line devices are usedwith a reference line coated with poly (methyl methacrylate) (PMMA) and a sensing line coated with a chemicallysensitive polymer, which acts as both a guiding layer anda sensing layer or with a PMMA waveguide and a chemically sensitive polymer. Results show the three-layermodel provides higher sensitivity than the four-layermodel. Contributions from mass loading and coatingviscoelasticity changes to the sensor response are evaluated, taking into account the added mass, swelling, andplasticization. Chemically sensitive polymers are investigated in the detection of low concentrations (1-60 ppm)of toluene, ethylbenzene, and xylenes in water. A low-ppblevel detection limit is estimated from the present experimental measurements. Sensor properties are investigatedby varying the sensor geometries, coating thicknesscombinations, coating properties, and curing temperaturefor operation in liquid environments. Partition coefficientsfor polymer-aqueous analyte pairs are used to explainthe observed trend in sensitivity for the polymers PMMA,poly(isobutylene), poly(epichlorohydrin), and poly(ethylacrylate) used in this work.